Part 4: Vessel Systems and Machinery

RULES FOR BUILDING AND CLASSING

STEEL VESSELS UNDER 90 METERS (295 FEET) IN

LENGTH
2011

PART 4
VESSEL SYSTEMS AND MACHINERY

American Bureau of Shipping

Incorporated by Act of Legislature of
the State of New York 1862

Copyright © 2010
American Bureau of Shipping
ABS Plaza
16855 Northchase Drive
Houston, TX 77060 USA
R u l e C h a n g e N o t i c e ( 2 0 0 6 )

Rule Change Notice (2011)

The effective date of each technical change since 1993 is shown in parenthesis at the end of the
subsection/paragraph titles within the text of each Part. Unless a particular date and month are shown, the
years in parentheses refer to the following effective dates:
(2000) and after 1 January 2000 (and subsequent years) (1996) 9 May 1996
(1999) 12 May 1999 (1995) 15 May 1995
(1998) 13 May 1998 (1994) 9 May 1994
(1997) 19 May 1997 (1993) 11 May 1993

Listing by Effective Dates of Changes from the 2006 Rules

EFFECTIVE DATE 1 January 2011 – shown as (2011)

(based on the contract date for new construction between builder and Owner)
Part/Para. No. Title/Subject Status/Remarks
4-1-1/37 Materials Containing Asbestos To align the requirements with IMO Res. MSC.282(86), adopting
SOLAS Reg II-1/3-5.2, which prohibits installation of materials
containing asbestos on all ships (both new construction and existing
vessels) after 1 January 2011.
4-2-1/7.3.3 High Pressure Common Rail System To provide design requirements and safety arrangements for high
(New) pressure common rail systems.
4-3-2/7 Materials and Testing To align the requirements with the Rules for Building and Classing
Steel Vessels.
4-4-1/9.11 Collision Bulkhead Penetrations To align the requirements with SOLAS Reg. II-1/12.5.1 and II-1/12.5.2
and limit the piping penetrations of the collision bulkhead to those
pipes which are for the exclusive purpose of dealing with the
contents of spaces/tanks located forward of the bulkhead.
4-4-2/1.1 General To require certification of the emergency fire pumps in alignment
with the Rules for Building and Classing Steel Vessels. To require
certification of pumps used in fixed water-based, or equivalent, local
application fire-fighting systems and the sprinkler system pump.
4-4-3/1 General Requirements of Bilge To align the requirements with the Rules for Building and Classing
Systems Steel Vessels.
4-4-3/7 Direct and Emergency Bilge Suctions To align the requirements with the Rules for Building and Classing
for Main Machinery Spaces Steel Vessels and the ABS Guidance Notes for the Application of
Ergonomics to Marine Systems.
4-4-3/9.1 General To clarify the requirements for shutoff valves or closing devices in
vent piping.
4-4-4/1.1.1 Tanks To incorporate requirements of IMO MSC.1/Circ.1322, which
requires that boundary area of a fuel oil tank that is common with
machinery spaces of category A be kept to a minimum and with the
Rules for Building and Classing Steel Vessels requiring that fuel oil
tanks not be exposed to direct flame contact from underneath.
4-4-4/Figure 1 Acceptable Fuel Oil Tanks To incorporate requirements of IMO MSC.1/Circ.1322, which
Arrangements Inside Category A requires that boundary area of a fuel oil tank that is common with
Machinery Spaces machinery spaces of category A be kept to a minimum and with the
Rules for Building and Classing Steel Vessels requiring that fuel oil
tanks not be exposed to direct flame contact from underneath.
4-4-8/1.5.1(a) General To clarify that only high pressure oxygen and acetylene piping is to
be certified as Group I piping.
4-5-2/37 Release of Smoke from Machinery To require arrangements to permit the release of smoke, in the event of
(New) Space fire, from a machinery space of Category A. To incorporate SOLAS
Reg. II-2/8.3.

ii ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 Part/Para. No. Title/Subject Status/Remarks
4-6-2/9.1.4 Back-up Protection To clarify the specific requirements for back-up fuse arrangements
and cascade protection. To align the requirements with the Rules for
Building and Classing Steel Vessels.
4-6-2/9.13.5 Undervoltage Protection and To clarify that motors provided with undervoltage protection (UVP)
Undervoltage Release will not automatically restart upon restoration of normal voltage,
after a stoppage due to a low voltage condition or voltage failure
condition. To clarify which motors are required to be provided with
undervoltage release.
4-7-4/Table 2 Control Station in Navigation Bridge To clarify the requirements for displays.
4-7-4/Table 3 Centralized Control and Monitoring To clarify the requirements for displays.
Station
4-7-4/Table 4A Monitoring of Propulsion Machinery To clarify the requirements for displays.
– Slow Speed (Crosshead) Diesel
Engines
4-7-4/Table 4B Monitoring of Propulsion Machinery To clarify the requirements for displays.
– Medium/High (Trunk Piston) Speed
Diesel Engines
4-7-4/Table 5 Monitoring of Propulsion Machinery To clarify the requirements for displays.
– Gas Turbine
4-7-4/Table 6A Monitoring of Propulsion Machinery To clarify the requirements for displays.
– Electric
4-7-4/Table 6B Instrumentation and Safety System To clarify the requirements for displays.
Functions in Centralized Control
Station – Generator Prime Mover for
Electric Propulsion
4-7-4/Table 7 Monitoring of Auxiliary Prime- To clarify the requirements for displays.
movers and Electric Generators

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 iii
PART Table of Contents

4
Vessel Systems and Machinery

CONTENTS
CHAPTER 1 General .................................................................................................... 1
Section 1 Classification of Machinery ....................................................3

CHAPTER 2 Prime Movers ........................................................................................ 14

Section 1 Internal Combustion Engines and Reduction Gears ...........16

CHAPTER 3 Propulsion and Maneuvering Machinery............................................ 25

Section 1 Propulsion Shafting..............................................................29
Section 2 Propellers .............................................................................38
Section 3 Steering Gear.......................................................................50
Section 4 Waterjets ..............................................................................62
Section 5 Propulsion Redundancy.......................................................64

CHAPTER 4 Pumps and Piping Systems ................................................................ 72

Section 1 General ................................................................................79
Section 2 Pumps, Pipes, Valves and Fittings ......................................87
Section 3 Bilge and Ballast Systems and Tanks ...............................114
Section 4 Fuel Oil and Lubricating Oil Systems and Tanks...............124
Section 5 Internal Combustion Engine Systems................................131
Section 6 Hydraulic and Pneumatic Systems ....................................132
Section 7 Cargo Systems ..................................................................136
Section 8 Other Piping Systems and Tanks ......................................142

CHAPTER 5 Fire Extinguishing Systems .............................................................. 147

Section 1 All Vessels .........................................................................150
Section 2 Requirements for Vessels 500 Gross Tons and Over .......157
Section 3 Requirements for Vessels Under 500 Gross Tons ............167

CHAPTER 6 Electrical Installations........................................................................ 169

Section 1 General ..............................................................................177
Section 2 Shipboard Systems............................................................186
Section 3 Shipboard Installation ........................................................212
Section 4 Machinery and Equipment .................................................235
Section 5 Specialized Installations.....................................................266
Section 6 Specialized Vessels and Services .....................................284

iv ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 CHAPTER 7 Shipboard Automatic or Remote Control and Monitoring
Systems .............................................................................................. 295
Section 1 General ..............................................................................300
Section 2 General Systems Design and Arrangement
Requirements.....................................................................305
Section 3 Automatic or Remote Propulsion Control and Monitoring
Systems .............................................................................320
Section 4 Vessels Classed with ACCU Notation ...............................323
Section 5 Vessels Classed with ABCU Notation ...............................347
Section 6 Vessels Less than 500 GT Having a Length Equal or
Greater than 20 m (65 ft) ...................................................348

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 v
This Page Intentionally Left Blank
PART Chapter 1: General

4
CHAPTER 1 General

CONTENTS
SECTION 1 Conditions of Classification of Machinery........................................... 3
1 General ...............................................................................................3
3 Certification of Machinery ...................................................................3
3.1 Basic Requirements ........................................................................ 3
3.3 Type Approval Program................................................................... 3
3.5 Non-mass Produced Machinery ...................................................... 4
3.7 Details of Certification of Some Representative Products ............... 4
5 Shipboard Automatic or Remote Control and Monitoring Systems ....4
7 Machinery Plans and Data..................................................................4
7.1 General............................................................................................ 4
7.3 Automation and Remote Control Systems....................................... 4
7.5 Boilers, Pressure Vessels and Heat Exchangers ............................ 5
7.7 Electrical Systems ........................................................................... 5
7.9 Fire Safety ....................................................................................... 6
7.11 Internal Combustion Engines .......................................................... 6
7.13 Piping Systems................................................................................ 7
7.15 Propellers ........................................................................................ 7
7.17 Reduction Gears ............................................................................. 8
7.19 Shafting ........................................................................................... 8
7.21 Steering Gears ................................................................................ 8
7.23 Thrusters (Steerable, Athwartship).................................................. 8
7.25 Waterjets ......................................................................................... 8
7.27 Windlass or Winch........................................................................... 8
9 Machinery ...........................................................................................9
11 Machinery Spaces ..............................................................................9
13 Definitions ...........................................................................................9
13.1 Category A Machinery Spaces ........................................................ 9
13.3 Machinery Spaces ........................................................................... 9
13.5 Oil Fuel Unit..................................................................................... 9
13.7 Accommodation Spaces.................................................................. 9
13.9 Public Spaces.................................................................................. 9
13.11 Service Spaces ............................................................................... 9
13.13 Cargo Spaces.................................................................................. 9
13.15 Special Category Spaces ................................................................ 9
13.17 Sources of Ignition......................................................................... 10
13.19 Vital Systems................................................................................. 10
13.21 Dead Ship Condition ..................................................................... 10
13.23 Blackout......................................................................................... 10

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 1
 15 Astern Propulsion Power ..................................................................11
15.1 General..........................................................................................11
15.3 Steam Turbine Propulsion .............................................................11
17 Inclinations ........................................................................................11
19 Dead Ship Start.................................................................................11
21 Machinery Equations ........................................................................11
23 Machinery Space Ventilation ............................................................11
25 Engineers’ Alarm...............................................................................11
27 Automatic Trips .................................................................................11
29 Thrusters and Dynamic Positioning Systems ...................................11
31 Boilers, Pressure Vessels and Turbines...........................................12
33 Sea Trial............................................................................................12
33.1 General..........................................................................................12
33.3 Residual Fuel.................................................................................12
35 Units ..................................................................................................12
37 Materials Containing Asbestos .........................................................12
39 Ambient Temperature .......................................................................12

TABLE 1 Machine Installations – Inclinations ........................................13

TABLE 2 Ambient Temperatures for Unrestricted Service.....................13

2 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 1: Conditions of Classification of Machinery

4
CHAPTER 1 General

SECTION 1 Conditions of Classification of Machinery

1 General
The provisions of Part 1, Chapter 1, “Scope and Conditions of Classification,” are applicable to the classification
of machinery.

3 Certification of Machinery (2003)

3.1 Basic Requirements

The Rules define, to varying degrees, the extent of evaluation required for products, machinery, equipment
and their components based on the level of criticality of each of those items. There are three basic evaluation
constituents:
• Design review; prototype testing;
• Survey during construction and testing at the plant of manufacture; and
• Survey during installation onboard the vessel and at trials.
Where design review is required by the Rules, a letter will be issued by ABS upon satisfactory review of
the plans to evidence the acceptance of the design. In addition to, or independent of, design review, ABS may
require survey and testing of forgings, castings and component parts at the various manufacturers’ plants as
well as survey and testing of the finished product. A certificate or report will be issued upon satisfactory
completion of each survey to evidence acceptance of the forging, casting, component or finished product.
Design review, survey and the issuance of reports or certificates constitute the certification of machinery.
Based on the intended service and application, some products do not require certification because they are
not directly related to the scope of classification or because normal practices for their construction within
the industry are considered adequate. Such products may be accepted based on the manufacturers’
documentation on design and quality.
In general, surveys during installation onboard the vessel and at trials are required for all items of machinery.
This is not considered a part of the product certification process. There may be instances, however, where
letters or certificates issued for items of machinery contain conditions which must be verified during
installation, tests or trials.

3.3 Type Approval Program

Products that can be consistently manufactured to the same design and specification may be Type
Approved under the ABS Type Approval Program. The ABS Type Approval Program is a voluntary option
for the demonstration of the compliance of a product with the Rules or other recognized standards. It may
be applied at the request of the designer or manufacturer. The ABS Type Approval Program generally
covers Product Type Approval (1-1-4/7.7.3 of the ABS Rules for Conditions of Classification (Part 1)), but
is also applicable for a more expeditious procedure towards Unit-Certification, as specified in 1-1-4/7.7.2 of
the above-referenced Part 1.
See the ABS Type Approval Program in Appendix 1-1-A3 of the ABS Rules for Conditions of
Classification (Part 1). The ABS Type Approval Program and the indicated references are available for
download from the ABS website at http://www.eagle.org.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 3
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

3.5 Non-mass Produced Machinery

Non-mass produced critical machinery, such as propulsion boilers, slow speed diesel engines, turbines,
steering gears and similar critical items are to be individually unit certified in accordance with the
procedure described in 4-1-1/3.1. However, consideration will be given to granting Type Approval to such
machinery in the categories of Acceptable Quality System (AQS) and Recognized Quality System (RQS).
The category of Product Quality Assurance (PQA) will not normally be available for all products, and such
limitations will be indicated in 4-1-1/Table 1 through 4-1-1/Table 6 of the ABS Rules for Building and
Classing Steel Vessels (Steel Vessel Rules). In each instant where Type Approval is granted, in addition to
quality assurance and quality control assessment of the manufacturing facilities, ABS will require some
degree of product-specific survey during manufacture.

3.7 Details of Certification of Some Representative Products

4-1-1/Tables 1 through 6 of the Steel Vessel Rules provide abbreviated certification requirements of
representative machinery based on the basic requirements of the Rules for machinery. The tables also provide
the applicability of the Type Approval Program for each of these machinery items.
For easy reference, the tables contain six product categories, as follows:
• Prime movers
• Propulsion, maneuvering and mooring machinery
• Electrical and control equipment
• Fire safety equipment
• Boilers, pressure vessels, fired equipment
• Piping system components

5 Shipboard Automatic or Remote Control and Monitoring Systems

(1998)
Automatic or remote control and monitoring systems associated with propulsion machinery and monitoring
systems of propulsion-machinery space installed onboard classed vessels are to comply with the requirements
in Section 4-7-1 through Section 4-7-3 or Section 4-7-6, as applicable. Additionally, where requested by
the Owner and provided that compliance with Section 4-7-4 or Section 4-7-5 is met, the aforementioned
systems will be assigned the optional notations ACCU or ABCU, respectively. See Section 4-7-1.

7 Machinery Plans and Data

The following plans and data, as applicable for each vessel to be built under survey, are to be submitted
and approved before construction is commenced, in accordance with Section 1-1-4 of the Supplement to
the ABS Rules for Conditions of Classification (Part 1). The sizes, dimensions, welding and other details,
make and size of standard approved appliances are to be shown on the plans as clearly and fully as possible.

7.1 General
Details of dead ship start arrangements (see 4-1-1/25).
Description of all automatic trips that may affect the vessel’s propulsion system

7.3 Automation and Remote Control Systems

A list of electrical, pneumatic or hydraulic equipment associated with the particular systems, including the
data listed in 4-7-1/7.1.
A list of all major components installed within the particular equipment (i.e., control console, etc.) and the
data as required in 4-7-1/7.1.

4 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

Certificates or test reports attesting to the suitability of the particular equipment in compliance with the
environmental criteria set forth in 4-7-2/15 and 4-7-2/17, as applicable. For equipment that have been
already certified by ABS and provided their certification remains valid, the submission of a copy of pertinent
certificate will suffice (see 4-7-2/17.3).
Plans showing the location of control and monitoring stations, controlled equipment and piping/cable runs,
etc.
Arrangements and details of the control consoles and panels, including plan views and elevation details,
installation details and wiring data as listed in 4-7-1/7.9.
A list of all cables connecting equipment associated with the systems (see 4-7-1/7.11).
A complete operational description of the automatic or remote control and monitoring systems (see 4-7-1/7.13).
A simplified one-line diagram (electrical and piping) of all power and automatic or remote control and
monitoring systems (see 4-7-1/7.15).
A schematic diagram of all control, alarm, display and safety systems.
For computer-based systems, the following is to be included:
• Overall description and specification of the systems and equipment.
• Block diagrams for the computer hardware showing interfacing between the work stations, input/output
(I/O) units, local controllers, traffic controllers, data highways, etc.
• Logic flow chart or ladder diagrams.
• Description of the alarm system indicating the ways it is acknowledged, displayed on the monitor or
mimic display board, etc.
• Description of the system redundancy and back-up equipment, if any.
• Description of the data communication protocol, including anticipated data process response delays.
• Description of the system’s security protocol to prevent unauthorized program changes which may
compromise the integrity of the automatic or remote systems.
• Description of the system with regard to the degree of independence or redundancy provided for the
control systems, alarm/display systems and safety systems.
• Description of system’s task priorities.
• Where applicable, description of UPS (uninterruptible power supply) and their capacities, including
system’s power consumption.
• Equipment ratings and environmental parameters.
Installation methods (electrical, pneumatic and hydraulic) (see 4-7-1/7.21).
A matrix chart for each of the systems indicating the information listed in 4-7-1/7.23 upon activation of a
given alarm or safety action.

7.5 Boilers, Pressure Vessels and Heat Exchangers

Arrangements and details of boilers, pressure vessels and heat exchangers required by Part 4, Chapter 4 of
the Steel Vessel Rules.
Plans and data for hydraulic and pneumatic power cylinders, as required by 4-4-6/3.

7.7 Electrical Systems

One line diagrams for the following electrical systems containing the information specified in 4-6-2/1.1.2.
• Power supply and distribution
• Lighting including navigation lights

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 5
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

• Internal communication
• General emergency alarm
• Fire detection and alarm
• Steering gear control
• Intrinsically-safe equipment
• Emergency generator starting
• Inert gas control, monitoring and alarm
• Semiconductor converters for propulsion
Short-circuit data (see 4-6-2/1.3)
Protective device coordination study (see 4-6-2/1.5)
Electric-plant load analysis (see 4-6-2/1.7)
Booklet of standard wiring practices and details (see 4-6-3/1.1)
General arrangement plan of electrical equipment showing the location of the equipment listed in 4-6-3/1.3
Location of splices and cable boxes together with information of their services
Hazardous area plan (see 4-6-3/1.5)
List of all equipment in hazardous areas (see 4-6-3/1.5)
Details of electrical components, as required by 4-6-4/1

7.9 Fire Safety (2010)

Arrangement and details of control station for emergency closing of openings and stopping machinery
Details and location of fireman’s outfits
Details of fire extinguishing appliances
Fire control plans (see 4-5-1/1.9)
Plans of the following systems:
• Fire main system
• Foam smothering system
• Fire detection systems
• Fixed gas extinguishing system
• Fixed water spraying system
Other fire extinguishing arrangements
For vessels 500 GRT and over, the most severe service condition for the operation of the emergency fire
pump (e.g., lightest draft as shown in Trim and Stability Booklet, etc.),
For vessels 500 GRT and over, calculations and pump data demonstrating that the emergency fire pump
system can meet the operational requirements specified in 4-5-2/5.3.3 and 4-5-2/5.3.6 with the proposed
pump location and piping arrangements (e.g., adequate suction lift, discharge pressure, capacity, etc.) at the
most severe service condition.

7.11 Internal Combustion Engines

Plans and particulars as required by Section 4-2-1 of the Steel Vessel Rules.

6 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

7.13 Piping Systems

Diagrammatic plans, as applicable, of the following piping systems containing the information specified in
4-4-1/3.3:
• Ballast system
• Bilge system
• Cargo systems
• Compressed air systems (including starting air systems and control systems)
• Cooling water systems
• Crude oil washing system
• Deck drains and scuppers
• Exhaust gas systems
• Essential fresh water service systems
• Fuel oil filling, transfer and service systems
• Hydraulic power piping systems
• Inert gas systems
• Lubricating oil systems
• Potable water system
• Sanitary system
• Essential Sea water service systems
• Steam system
• Vent, sounding and overflow piping
• Systems conveying toxic liquids, liquids with a flash point below 60°C (140°F), or flammable gases
• All Group I piping systems not covered above unless it is part of an independently manufactured unit
(such as air conditioning or refrigeration) that does not form part of a vessel’s piping system
A booklet of standard piping practices and details (see 4-4-1/3.5)
Plans of molded or built-up flexible expansion joints in seawater piping systems over 150 mm (6 in.),
including details of the reinforcement arrangements (see 4-4-1/9.7)
Specifications for plastic pipes and components, including thermal and mechanical properties and chemical
resistance (see 4-4-2/7, 4-4-2/9.11 and 4-4-2/17.7)
Drawings of non-standard valves and fittings showing details of construction, materials and basis for
pressure rating (see 4-4-2/11.1.2 and 4-4-2/13.5)
Valve operating systems for all remote-controlled valves

7.15 Propellers
For all propellers, a propeller plan giving design data and characteristics of the material
For skewed propellers or propeller blades of unusual design, a detailed stress analysis, as required by 4-3-2/9.3
or 4-3-2/11.3.
For controllable pitch propellers, plans of the propeller hub, propeller blade flange and bolts, internal
mechanisms, hydraulic piping control systems, and instrumentation and alarm systems; also strength
calculations for the internal mechanism
Detailed stress calculations and fitting instructions for keyless propeller connections

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 7
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

7.17 Reduction Gears

Arrangements, details and data as required by Section 4-3-1 of the Steel Vessel Rules.

7.19 Shafting (2008)

Detailed plans with material specifications of the propulsion shafting, couplings, coupling bolts*, propulsion
shafting arrangement, tailshaft bearings and lubrication system, if oil-lubricated
Calculations for flexible couplings and demountable couplings (see 4-2-1/17 and 4-3-1/19.7)
Shaft alignment and vibration calculations, if required by 4-3-1/21
Detailed preloading and stress calculations and fitting instructions for non-fitted coupling bolts (see 4-3-1/19.3)
* Note: Specific details regarding the interference fit of the coupling bolts are to be submitted. In addition, calculations
and detail design basis for the sizing of the fitted bolts are to be submitted if the sizing of the bolts as per 4-3-
1/19.1 of the Rules is not based on as-built line shaft diameter “D”.

7.21 Steering Gears

General arrangements of the main and auxiliary steering gears and steering compartment
Assembly of upper rudder stock, tiller, tie rod, rudder actuators, etc.
Construction details of all torque-transmitting components such as tiller, tiller pin, tiller/rudder stock
interference fit mechanism, tie rod, rudder actuator, etc., including bill of materials, welding procedures
and nondestructive testing, as applicable
Control system incorporating schematic electrical control logic diagram, instrumentation, alarm devices,
etc., and including bill of materials
Design calculations for torque-transmitting components such as tiller, tie rod, rudder actuator, etc.
Details of electrical power supply to power units and to steering gear control, including schematic diagram
of motor controllers, feeder cables and feeder cable electrical protection
Rated torque of main steering gear
Schematic hydraulic piping plan incorporating hydraulic logic diagram and including bill of materials,
typical pipe to pipe joint details, pipe to valve joint details, pipe to equipment joint details, pressure rating
of valves and pipe fittings and pressure relief valve settings

7.23 Thrusters (Steerable, Athwartship)

Drawings and data as per 4-3-5/1.7 of the Steel Vessel Rules.

7.25 Waterjets
Details and material specifications of force transmitting parts
Design basis stress calculations for the impellers, shafting, steering mechanism and reversing mechanism
(see 4-3-4/1.3)
Calculations or test results to substantiate the suitability and strength of the pressure and suction housing
(see 4-3-4/1.5)

7.27 Windlass or Winch

Arrangements, details and stress calculations for the windlass or winch, drums, brakes, shaft, gears,
coupling bolts, wildcat, sheaves, pulleys and foundation.
Control arrangements
Electric one-line diagram, including power ratings and cable specifications
Piping system diagram, including working pressures, welding details, material specifications and pipe
specifications

8 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

9 Machinery
Rotating machinery of 100 kilowatts (135 horsepower) and over is to be in accordance with the requirements
of Part 4, Chapters 1 through 6, as applicable. Machinery of less than 100 kilowatts (135 horsepower) is to
be designed, constructed and equipped in accordance with good commercial practice, and will be accepted
subject to a satisfactory performance test conducted to the satisfaction of the Surveyor after installation.

11 Machinery Spaces
Machinery spaces are to be arranged so as to provide access to all machinery and controls as necessary for
operation or maintenance.

13 Definitions
For the purpose of machinery installations, electrical installations, periodically unattended machinery
spaces, fire protection, fire detection and fire extinction, the following terms are defined:

13.1 Category A Machinery Spaces

Machinery spaces of Category A are those spaces and trunks to such spaces that contain: internal combustion
machinery used for main propulsion; internal combustion machinery used for purposes other than main
propulsion, where such machinery has an aggregate total power output of not less than 375 kW (500 HP);
oil fired equipment such as an inert gas generator, incinerator, waste disposal unit, etc.; or any oil fuel units.

13.3 Machinery Spaces

Machinery spaces are Category A spaces and all other spaces containing propelling machinery, internal
combustion engines, boilers, generators, major electrical equipment, refrigerating, stabilizing, ventilation
and air conditioning machinery, similar spaces and trunks to such spaces.

13.5 Oil Fuel Unit

An oil-fuel unit is any equipment, such as pumps, filters and heaters, used for the preparation and delivery
of fuel oil to oil-fired boilers (including incinerators and inert gas generators), internal combustion engines
or gas turbines at a pressure of more than 1.8 bar (1.8 kgf/cm2, 26 psi).

13.7 Accommodation Spaces

Accommodation spaces are those spaces used for public spaces, corridors, lavatories, cabins, offices, hospitals,
cinemas, games and hobbies rooms, barber shops, pantries containing no cooking appliances and similar
spaces.

13.9 Public Spaces

Public spaces are those portions of the accommodations which are used for meeting halls, dining rooms,
lounges and similar permanently enclosed spaces.

13.11 Service Spaces

Service spaces are those spaces used for galleys, pantries containing cooking appliances, lockers, mail and
specie rooms, storerooms, workshops other than those forming part of the machinery spaces, similar spaces
and trunks to such spaces.

13.13 Cargo Spaces

Cargo spaces are all spaces used for cargo (including cargo oil tanks) and trunks to such spaces.

13.15 Special Category Spaces

Special category spaces are those enclosed spaces above or below the bulkhead deck intended for the
carriage of motor vehicles with fuel in their tanks for their own propulsion, into and from which such
vehicles can be driven and to which passengers have access.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 9
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

13.17 Sources of Ignition

Sources of ignition are considered to include a flame, arc, spark and electrical equipment, machinery and
other equipment having hot surfaces with the potential of causing a non-intentional explosion or fire when
exposed to an explosive or flammable atmosphere or material.

13.19 Vital Systems

Vital systems are those systems necessary for the vessel’s survivability and safety, including:
i) Systems for fill, transfer and service of fuel oil.
ii) Fire-main systems, including emergency fire pump.
iii) Other required fire-extinguishing and detection systems.
iv) Bilge systems, including emergency bilge suction.
v) Ballast systems.
vi) Steering systems and steering control systems.
vii) Propulsion systems and their necessary auxiliaries (fuel oil, lube oil, cooling water, starting system,
etc.) and control systems.
viii) Systems for transfer and control of cargo.
ix) Ship’s service and emergency electrical generation systems and their auxiliaries (fuel oil, lube oil,
cooling water, starting system, etc.) and control systems.
x) Venting and sounding systems.
xi) Engine room ventilation systems.
xii) Other required ventilation systems.
xiii) Controllable pitch propeller systems, including controls.
xiv) Electrical power and lighting systems.
xv) Systems used for navigation.
xvi) Required communication and alarm systems.
xvii) Hydraulic systems for anchor windlass/winch.
xviii) Systems necessary due to special characteristics or special service of a vessel.
xix) Any other system identified by ABS as crucial to the survival of the vessel or to the protection of
the personnel aboard.

13.21 Dead Ship Condition (2004)

Dead ship condition means a condition under which:
i) The main propulsion plant, boilers and auxiliary machinery are not in operation due to the loss of
the main source of electrical power, and
ii) In restoring propulsion, the stored energy for starting the propulsion plant, the main source of
electrical power and other essential auxiliary machinery is assumed to be not available.

13.23 Blackout (2004)

Blackout situation means the loss of the main source of electrical power resulting in the main and auxiliary
machinery to be out of operation.

10 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

15 Astern Propulsion Power (2005)

15.1 General
Sufficient power for going astern is to be provided to secure proper control of the vessel in all normal
circumstances. The astern power of the main propelling machinery is to be capable of maintaining in free
route astern at least 70% of the ahead rpm corresponding to the maximum continuous ahead power. For
main propulsion systems with reversing gears, controllable pitch propellers or electric propulsion drive,
running astern is not to lead to overload of the propulsion machinery. The ability of the machinery to
reverse the direction of thrust of the propeller in sufficient time, and so to bring the vessel to rest within a
reasonable distance from maximum ahead service speed, is to be demonstrated and recorded during trials.

15.3 Steam Turbine Propulsion

Where steam turbines are used for main propulsion, they are to be capable of maintaining in free route
astern at least 70% of the ahead revolutions for a period of at least 15 minutes. The astern trial is to be
limited to 30 minutes or is to be in accordance with manufacturer’s recommendation to avoid overheating
of the turbine due to the effects of “windage” and friction.

17 Inclinations
Machinery installations are to be designed to operate under the conditions as shown in 4-1-1/Table 1.

19 Dead Ship Start (2005)

Means are to be provided to bring the machinery into operation from a “dead ship” condition as defined in
4-1-1/13.21. See 4-6-2/3.1.3 and 4-6-3/3.27 for the required starting arrangements.

21 Machinery Equations
The equations for rotating parts of the machinery in the following sections are based upon strength
considerations only. Their application does not relieve the manufacturer from responsibility for the
presence of dangerous vibrations in the installation at speeds within the operating range. See also 4-3-1/21.

23 Machinery Space Ventilation

Machinery spaces are to be ventilated so as to ensure that when machinery is operating at full power in all
weather conditions, including heavy weather, an adequate supply of air is maintained for operation of the
machinery and safety of the personnel.

25 Engineers’ Alarm (1998)

See 4-6-2/17.3.

27 Automatic Trips
A description of all automatic trips that may affect the vessel’s propulsion system is to be submitted for review.

29 Thrusters and Dynamic Positioning Systems

Compliance with Section 4-3-5 of the Steel Vessel Rules is required as a condition for Class for main
propulsion thrusters and is optional for propulsion-assist thrusters, athwartship thrusters and dynamic
positioning systems, including their thrusters.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 11
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

31 Boilers, Pressure Vessels and Turbines

When fitted, boilers and pressure vessels are to be designed and constructed in accordance with Part 4,
Chapter 4 of the Steel Vessel Rules. Turbines are to comply with Sections 4-2-3 and 4-2-4 of the Steel
Vessel Rules.

33 Sea Trial

33.1 General
A final underway trial is to be made of all machinery, including the steering gear, anchor windlass and
ground tackle. The entire installation is to be operated in the presence of the Surveyor to demonstrate its
reliability and capability to function satisfactorily under operating conditions and its freedom from harmful
vibrations within the operating range. The ability of the machinery to reverse the direction of thrust of the
propeller from maximum ahead speed and to bring the vessel to rest is to be demonstrated on sea trials to
the satisfaction of the Surveyor.
All automatic controls, including trips which may affect the vessel’s propulsion system, are to be tested
underway or alongside the pier to the satisfaction of the Surveyor.
See also 4-3-3/15.3, 4-2-1/19 and 4-2-1/21.

33.3 Residual Fuel

The viscosity of the fuel used on the sea trial will be entered in the classification report.

35 Units
These Rules are written in three systems of units, i.e., SI units, MKS units and US customary units. Each
system is to be used independently of any other system. Unless indicated otherwise, the format presentation
in the Rules of the three systems of units is as follows:
SI units (MKS units, US customary units).

37 Materials Containing Asbestos (2011)

Installation of materials which contain asbestos is prohibited.

39 Ambient Temperature (2008)

For vessels of unrestricted service, ambient temperature, as indicated in 4-1-1/Table 2, is to be considered
in the selection and installation of machinery, equipment and appliances. For vessels of restricted or special
service, the ambient temperature appropriate to the special nature is to be considered.

12 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 1 General
Section 1 Conditions of Classification of Machinery 4-1-1

TABLE 1
Machine Installations – Inclinations
Angle of Inclination, Degrees (1)
Athwartships Fore & Aft
Installations, Components Static Dynamic Static Dynamic
Main and auxiliary machinery 15 22.5 5 7.5
Safety Equipment
emergency power installations (3) 22.5 22.5 10 10
emergency fire pumps and their drives 22.5 22.5 10 10
Switchgear
electrical and electronic appliances 22.5 (2) 22.5 (2) 10 10
and remote control systems
Notes:
1 Athwartships and fore-aft inclinations occur simultaneously.
2 Up to an angle of inclination of 45 degrees, switches and controls are to remain in their last set
position.
3 In vessels designed for the carriage of liquefied gases and of chemicals, the emergency power
installation is to remain operable with the vessel flooded to its permissible athwartships inclination
up to a maximum of 30 degrees.

TABLE 2
Ambient Temperatures for Unrestricted Service (2008)
Location Temperature Range (°C)
(1, 2)
Air Enclosed spaces 0 to 45
Open deck (1) –25 to 45

Temperature (°C)
Seawater 32
Notes:
1 Electronic equipment is to be suitable for operations even with an air temperature of 55°C. See also 4-6-1/17.3.
For automatic or remote control and monitoring systems required to meet 4-7-2/Table 1 or 4-9-7/Table 9 of the
Steel Vessel Rules, see test 3 of 4-7-2/Table 1, or test 3 of 4-9-7/Table 9 of the Steel Vessel Rules.
2 Electrical equipment in machinery spaces is to be designed for 45°C, except that electric generators and motors are
to be designed for 50°C. Electrical equipment outside machinery space may be designed for 40°C.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 13
PART Chapter 2: Prime Movers

4
CHAPTER 2 Prime Movers

CONTENTS
SECTION 1 Internal Combustion Engines and Reduction Gears......................... 16
1 General .............................................................................................16
1.1 Construction and Installation .........................................................16
1.3 Piping Systems ..............................................................................16
1.5 Pressure Vessels and Heat Exchangers .......................................16
1.7 Torsional Vibration Stresses..........................................................16
1.9 Strengthening for Navigation in Ice................................................16
1.11 Crankcase Ventilation....................................................................16
1.13 Warning Notices ............................................................................17
1.15 Bedplate ........................................................................................17
3 Fuel Oil Pumps and Oil Heaters .......................................................17
3.1 Transfer Pumps .............................................................................17
3.3 Booster Pumps ..............................................................................17
3.5 Heaters ..........................................................................................17
5 Fuel Oil Pressure Piping ...................................................................17
7 Fuel Oil Injection System ..................................................................18
7.1 General..........................................................................................18
7.3 Piping Between Injection Pump and Injectors................................18
7.5 Piping Between Booster Pump and Injection Pumps.....................18
9 Lubricating Oil Systems ....................................................................19
9.1 General..........................................................................................19
9.3 Low Oil Pressure Alarms, Temperature and Level Indicators........19
9.5 Drain Pipes ....................................................................................19
9.7 Lubricating Oil Pumps....................................................................19
9.9 Filters.............................................................................................19
9.11 Lubricating-Oil Systems for Reduction Gears................................19
11 Cooling Water Systems ....................................................................20
11.1 General..........................................................................................20
11.3 Sea Suctions .................................................................................20
11.5 Strainers ........................................................................................20
11.7 Circulating Water Pumps ...............................................................20
13 Starting Systems...............................................................................21
13.1 Starting Air Systems ......................................................................21
13.3 Starting Air Capacity ......................................................................21
13.5 Starting Air Compressors...............................................................22
13.7 Protective Devices for Starting-air Mains.......................................22
13.9 Electrical Starting...........................................................................22
13.11 Hydraulic Starting ..........................................................................22

14 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 15 Engine Exhaust Systems ..................................................................23
15.1 General.......................................................................................... 23
15.3 Exhaust System Materials ............................................................. 23
15.5 Exhaust Gas Temperature ............................................................ 23
17 Couplings ..........................................................................................23
17.1 Flexible Shaft Couplings................................................................ 23
17.3 Flanged Couplings and Coupling Bolts ......................................... 23
19 Testing of Pumps Associated with Engine and Reduction Gear
Operation ..........................................................................................23
19.1 Pumps Hydrostatic Tests............................................................... 23
19.3 Capacity Tests............................................................................... 23
21 Trial ...................................................................................................24

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 15
PART Section 1: Internal Combustion Engines and Reduction Gears

4
CHAPTER 2 Prime Movers

SECTION 1 Internal Combustion Engines and Reduction Gears

1 General

1.1 Construction and Installation

Internal combustion engines of 100 kW [135 horsepower (hp)] and over and associated reduction gears are
to be constructed in accordance with Part 4, Chapters 2 and 3 of the Steel Vessel Rules and installed in
accordance with the following requirements to the satisfaction of the Surveyor. Engines of less than 100 kW
(135 hp) and associated reduction gears are to be constructed and equipped in accordance with good
commercial practice, and will be accepted subject to a satisfactory performance test conducted to the
satisfaction of the Surveyor after installation.
For engines driving generators, refer to the applicable requirements of 4-6-4/3.17 and 4-6-4/3.19.

1.3 Piping Systems

In addition to requirements for the specific system in this section, piping systems are to comply with the
applicable requirements in Part 4, Chapter 4.

1.5 Pressure Vessels and Heat Exchangers

Pressure vessels and heat exchangers are to be in accordance with the applicable requirements of Part 4,
Chapter 4 of the Steel Vessel Rules.

1.7 Torsional Vibration Stresses

Refer to 4-3-1/21.

1.9 Strengthening for Navigation in Ice

For gears designed for navigation in ice, see Part 6, Chapter 1 of the Steel Vessel Rules.

1.11 Crankcase Ventilation

1.11.1 General
Provision is to be made for ventilation of an enclosed crankcase by means of a small breather or
by means of a slight suction not exceeding 25.4 mm (1 in.) of water. Crankcases are not to be
ventilated by a blast of air. Otherwise, the general arrangements and installation are to be such as
to preclude the possibility of free entry of air to the crankcase.
1.11.2 Piping Arrangement
Crankcase ventilation piping is not to be directly connected with any other piping system.
Crankcase ventilation pipes from each engine are normally to be led independently to the weather
and fitted with corrosion-resistant flame screens. However, crankcase ventilation pipes from two
or more engines may lead to a common oil mist manifold.

16 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

Where a common oil mist manifold is employed, the vent pipes from each engine are to be led
independently to the manifold and fitted with a corrosion-resistant flame screen within the
manifold. The arrangement is not to violate the engine manufacturer’s recommendations for
crankcase ventilation. The common oil mist manifold is to be accessible at all times under normal
conditions and effectively vented to the weather. Where venting of the manifold to the weather is
accomplished by means of a common vent pipe, the location of the manifold is to be as close as
practicable to the weather such that the length of the common vent pipe is no greater than one
deck height. The clear open area of the common vent pipe is not to be less than the aggregate
cross-sectional area of the individual vent pipes entering the manifold, and the outlet to the
weather is to be fitted with a corrosion-resistant flame screen. The manifold is also to be fitted
with an appropriate draining arrangement.

1.13 Warning Notices

Suitable warning notices are to be attached in a conspicuous place on each engine and are to caution
against the opening of a hot crankcase for a specified period of time after shutdown based upon the size of
the engine, but not less than 10 minutes in any case. Such notice is also to warn against restarting an
overheated engine until the cause of overheating has been remedied.

1.15 Bedplate
The bedplate or crankcase is to be of rigid construction, oiltight, and provided with a sufficient number of
bolts to secure the same to the vessel’s structure. The structural arrangements for supporting and securing
the main engines are to be submitted for approval. Refer to 3-2-4/11 for structural requirements. For welded
construction, see also Chapter 4 of the ABS Rules for Materials and Welding (Part 2).

3 Fuel Oil Pumps and Oil Heaters

3.1 Transfer Pumps

Refer to 4-4-4/3.

3.3 Booster Pumps

A stand-by fuel-oil booster pump is to be provided for main engines having independently driven booster
pumps. For main engines having attached fuel pumps, a complete pump may be carried as a spare in lieu of
the standby pump. For multiple engines using identical, attached fuel pumps, only one complete pump
needs to be carried as a spare.

3.5 Heaters
When fuel oil heaters are required for main engine operation, at least two heaters of approximately equal
size are to be installed. The combined capacity of the heaters is to be not less than required to supply the
main engine(s) at full power.

5 Fuel Oil Pressure Piping

Pipes from booster pumps to injection systems are to be at least standard seamless steel. Pipes conveying
heated oil are to be at least standard seamless or electric-resistance-welded steel. ERW pipe is to be straight
seam and fabricated with no filler metal (e.g., ABS Grade 2 or 3 ERW). Valves and fittings may be screwed
in sizes up to and including 60 mm O.D. (2 in. N.P.S.), but screwed unions are not to be used on pressure
lines in sizes 33 mm O.D. (1 in.) and over. Valves are to be so constructed as to permit packing under pressure.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 17
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

7 Fuel Oil Injection System

7.1 General
Strainers are to be provided in the fuel oil injection pump suction line.
For main propulsion engines, the arrangement is to be such that the strainers may be cleaned without
interrupting the fuel supply to the engine. However, where multiple engines are provided, a dedicated simplex
strainer may be fitted for each engine, provided the vessel can maintain at least one-half of the design
speed or seven knots, whichever is less, while operating with one engine temporarily out of service until its
strainer can be cleaned.
For auxiliary engines, the arrangement is to be such that the strainers may be cleaned without undue
interruption of power necessary for propulsion. Multiple auxiliary engines, each fitted with a separate strainer
and arranged such that changeover to a standby unit can be accomplished without loss of propulsion
capability, will be acceptable for this purpose.
Where strainers are fitted in parallel to enable cleaning without disrupting the oil supply, means are to be
provided to minimize the possibility of a strainer being opened inadvertently. Strainers are to be provided
with suitable means for venting when being put in operation and being depressurized before being opened.
Strainers are to be so located that in the event of leakage, oil cannot be sprayed on to the exhaust manifold
or surfaces with temperatures in excess of 220°C (428°F).
The injection lines are to be of seamless drawn pipe. Fittings are to be extra heavy. The material used may
be either steel or nonferrous, as approved in connection with the design. Also refer to 4-4-4/3.7.

7.3 Piping Between Injection Pump and Injectors (2005)

7.3.1 Injection Piping
All external high pressure fuel delivery lines between the high-pressure fuel pumps and fuel
injectors are to be protected with a jacketed piping system capable of containing fuel from a high-
pressure line failure. A jacketed pipe incorporates an outer pipe into which the high-pressure fuel
pipe is placed, forming a permanent assembly. Metallic hose of an approved type may be accepted
as the outer pipe, where outer piping flexibility is required for the manufacturing process of the
permanent assembly. The jacketed piping system is to include means for collection of leakages
and arrangements are to be provided for an alarm to be given of a fuel line failure.
7.3.2 Fuel oil Return Piping
When the peak to peak pressure pulsation in the fuel oil return piping from the injectors exceeds
20 bar (20.5 kgf/cm2, 285 psi), jacketing of the return pipes is also required.
7.3.3 High Pressure Common Rail System (2011)
Where a high pressure common rail system is fitted to an engine, the high pressure common rail is
to be in accordance with Section 4-4-1 of the Steel Vessels Rules for pressure vessels, or a recognized
standard as listed in 4-4-1/1.5 of the Steel Vessels Rules. Alternatively, the design may be verified
by certified burst tests. Components are to be made of steel or cast steel. Components made of
steel, other than cast steel, are to withstand not less than 4 times the maximum allowable working
pressure. The cast steel common rails are to withstand not less than 5 times the maximum allowable
working pressure. The use of non-ferrous materials, cast iron and nodular iron is prohibited.
Materials are to comply with Chapter 3 of the ABS Rule for Materials and Welding (Part 2).
The high pressure common rail system is required to be properly enclosed and provided with
arrangement for leak collection and alarm in case of a failure of high pressure common rail
system, see 4-2-1/7.3.1.

7.5 Piping Between Booster Pump and Injection Pumps (2005)

Spray shields are to be fitted around flanged joints, flanged bonnets and any other flanged or threaded
connections in fuel oil piping systems under pressure exceeding 1.8 bar (1.84 kgf/cm2, 26 psi) which are
located above or near units of high temperature, including boilers, steam pipes, exhaust manifolds, silencers
or other equipment required to be insulated by 4-4-4/1.1.2, and to avoid as far as practicable oil spray or oil
leakage into machinery air intakes or other sources of ignition. The number of joints in such piping systems is
to be kept to a minimum.

18 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

9 Lubricating Oil Systems

9.1 General
The following requirements are applicable for main and auxiliary diesel engines and for reduction gears
associated with diesel propulsion. See also 4-1-1/17 and 4-4-4/9.

9.3 Low Oil Pressure Alarms, Temperature and Level Indicators

An alarm device with audible and visual signals for failure of the lubricating oil system is to be fitted.
Pressure and temperature indicators are to be installed in lubricating oil systems indicating that the proper
circulation is being maintained.

9.5 Drain Pipes

Lubricating oil drain pipes from the sump to the drain tank are to be submerged at their outlet ends. No
interconnection is to be made between the drain pipes from the crankcases of two or more engines.

9.7 Lubricating Oil Pumps

In cases where forced lubrication is used for propulsion engines, one independently driven standby pump is
to be provided in addition to the necessary pumps for normal operation. Where the size and design of an
engine is such that lubrication before starting is not necessary and an attached lubricating pump is normally
used, an independently driven standby pump is not required if a complete duplicate of the attached pump is
carried as a spare. For multiple engines using identical attached lubricating-oil pumps, only one complete
pump needs to be carried as a spare.

9.9 Filters (1998)

Oil filters are to be provided. In the case of main propulsion engines which are equipped with full-flow-
type filters, the arrangement is to be such that the strainers may be cleaned without interrupting the oil
supply. However, where multiple engines are provided, a dedicated simplex strainer may be fitted for each
engine provided the vessel can maintain at least one-half of the design speed or 7 knots, whichever is less,
while operating with one engine temporarily out of service until its filter can be cleaned.
For auxiliary engines, the arrangement is to be such that the filters may be cleaned without undue interruption
of power necessary for propulsion. Multiple auxiliary engines, each fitted with a separate filter and arranged
such that changeover to a standby unit can be accomplished without loss of propulsion capability, will be
acceptable for this purpose.
The arrangement of the valving is to be such as to avoid release of debris into the lubricating-oil system
upon activation of the relieving mechanism.
Where filters are fitted in parallel to enable cleaning without disrupting the oil supply, means are to be
provided to minimize the possibility of a filter under pressure being opened inadvertently. Filters are to be
provided with suitable means for venting when being put in operation and being depressurized before
being opened. Valves and cocks with drain pipes led to a safe location are to be used for this purpose.
Filters are to be so arranged as to prevent, in the event of leakage, spraying of oil onto the exhaust manifold
and surfaces with temperatures in excess of 220°C (428°F).

9.11 Lubricating-Oil Systems for Reduction Gears

Where a reduction gear is driven by a single engine and a common lubricating-oil system is used for both
the engine and gear, the requirements in 4-2-1/9.1 through 4-2-1/9.9 are applicable.
Where a reduction gear is driven by more than one engine or any other case where a separate lubricating-
oil system is provided for the reduction gear, the following requirements are applicable.
9.11.1 Pumps
Two lubricating-oil pumps are to be provided, at least one of which is to be independently driven.
The capacity of each pump is to be sufficient for continuous operation of the main propulsion
plant at its maximum rated power.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 19
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

9.11.2 Coolers
One or more lubricating oil coolers with means for controlling the oil temperature is to be provided
together with two separate cooling water pumps, at least one of which is to be independently driven.
The coolers are to have sufficient capacity to maintain the required oil temperature while the main
propulsion plant is operating continuously at its maximum rated power.
9.11.3 Indicators
Indicators are to be fitted by which the pressure and temperature of the water inlet and oil outlet
may be determined. Gravity tanks are to be fitted with a low level alarm and a sight glass is to be
fitted in the overflow line to the sump. Pressure systems are to be fitted with a low pressure alarm.
Sump and gravity tanks are to be provided with suitable gauges for determining the level of oil
within the tank.
9.11.4 Filters
A filter is to be provided in the lubricating-oil piping to each reduction gear. The requirements in
4-2-1/9.9 are applicable.

11 Cooling Water Systems

11.1 General
Means are to be provided to ascertain the temperature of the circulating water at the return from each
engine and to indicate that the proper circulation is being maintained. Drain cocks are to be provided at the
lowest point of all jackets. For relief valves, see 4-4-1/9.15.

11.3 Sea Suctions

At least two independent sea suctions are to be provided for supplying water to the engine jackets or to the
heat exchangers. The sea suctions are to be located so as to minimize the possibility of blanking off the
cooling water.

11.5 Strainers
Where seawater is used for direct cooling of the engines, unless other equivalent arrangements are specially
approved, suitable strainers are to be fitted between the sea valves and the pump suctions. The strainers are
to be either of the duplex type or otherwise arranged so they can be cleaned without interrupting the cooling
water supply.

11.7 Circulating Water Pumps

There are to be at least two means for supplying cooling water to main and auxiliary engines, compressors,
coolers, reduction gears, etc. One of these means is to be independently driven and may consist of a
connection from a suitable pump of adequate size normally used for other purposes, such as a general
service pump, or in the case of fresh-water circulation, one of the vessel’s fresh-water pumps. Where, due
to the design of the engine, the connection of an independent pump is impracticable, the independently
driven stand-by pump will not be required if a complete duplicate of the attached pump is carried as a
spare. For multiple propulsion engines using identical attached pumps, only one complete pump needs to
be carried as a spare. Multiple auxiliary engine installations utilizing attached pumps need not be provided
with spare pumps.

20 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

13 Starting Systems

13.1 Starting Air Systems (2006)

The design and construction of all air receivers are to be in accordance with the applicable requirements of
Part 4, Chapter 4 of the Steel Vessel Rules. The piping system is to be in accordance with the applicable
requirements of Part 4, Chapter 4 of these Rules. The air receivers are to be so installed as to make the
drain connections effective under extreme conditions of trim. Compressed air systems are to be fitted with
relief valves and each container which can be isolated from a relief valve is to be provided with its own safety
valves or equivalent. Connections are also to be provided for cleaning the air container and pipe lines.
All discharge pipes from starting air compressors are to be led directly to the starting air receivers, and all
starting pipes from the air receivers to main or auxiliary engines are to be entirely separate from the
compressor discharge piping system.

13.3 Starting Air Capacity

Vessels having main engines arranged for air starting are to be provided with at least two starting-air
containers of approximately equal size. The total capacity of the starting-air containers is to be sufficient to
provide, without recharging the containers, at least the number of starts stated below.
If other compressed air systems, such as control air, are supplied from starting air containers, the capacity
of the containers is to be sufficient for continued operation of these systems after the air necessary for the
required number of consecutive starts has been used.
13.3.1 Diesel Propulsion
The minimum number of consecutive starts (total) required to be provided from the starting-air
containers is to be based upon the arrangement of the engines and shafting systems as indicated in
the following table.

Single Propeller Vessels Multiple Propeller Vessels

Engine Type One engine coupled Two or more One engine coupled Two or more engines
to shaft directly or engines coupled to to each shaft coupled to each shaft
through reduction shaft through clutch directly or through through clutch and
gear and reduction gear reduction gear reduction gear
Reversible 12 16 16 16
Non-reversible 6 8 8 8

For arrangements of engine and shafting systems which differ from those indicated in the table,
the capacity of the starting-air containers will be specially considered based on an equivalent
number of starts.
13.3.2 Diesel-electric Propulsion (2006)
The minimum number of consecutive starts required to be provided from the starting-air containers
is to be determined from the following equation:
S = 6 + G(G − 1)
where
S = total number of consecutive starts
G = number of engines necessary to maintain sufficient electrical load to permit
vessel transit at full seagoing power and maneuvering. The value of G need
not exceed 3.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 21
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

13.5 Starting Air Compressors

For vessels having internal-combustion engines arranged for air starting, there are to be two or more air
compressors, at least one of which is to be driven independently of the main propulsion unit, and the total
capacity of air compressors driven independently of the main propulsion unit is to be not less that 50% of
the total required.
The total capacity of the air compressors is to be sufficient to supply within one hour the quantity of the air
need to satisfy 4-2-1/13.3 by charging the receivers from atmospheric pressure. The capacity is to be
approximately equally divided between the number of compressors fitted, excluding an emergency compressor,
where fitted.
The arrangement for dead ship air starting is to be such that the necessary air for the first charge can be
produced onboard without external aid. See 4-1-1/19.

13.7 Protective Devices for Starting-air Mains

In order to protect starting air mains against explosions arising from improper functioning of starting
valves, an isolation non-return valve or equivalent is to be installed at the starting air supply connection to
each engine. Where engine bores exceed 230 mm (91/16 in.), a bursting disc or flame arrester is to be fitted
in way of the starting valve of each cylinder for direct reversing engines having a main starting manifold or
at the supply inlet to the starting-air manifold for nonreversing engines.
The above requirement is applicable to engines where the air is directly injected into the cylinder. It is not
intended to apply to engines utilizing air start motors.

13.9 Electrical Starting

13.9.1 Main Engine
Where the main engine is arranged for electric starting, at least two separate batteries (or separate
sets of batteries) are to be fitted. The arrangement is to be such that the batteries (or sets of
batteries) cannot be connected simultaneously in parallel. Each battery (or set) is to be capable of
starting the main engine when in cold and ready to start conditions. The combined capacity of the
batteries is to be sufficient without recharging to provide within 30 minutes the number of starts of
main engines as required for air starting in 4-2-1/13.3, and if arranged also to supply starting for
auxiliary engines, the number of starts required in 4-2-1/13.9.2. See also 4-2-1/13.9.3.
13.9.2 Auxiliary Engine
Electric starting arrangements for auxiliary engines are to have at least two separate batteries (or
separate sets of batteries) or may be supplied by separate circuits from the main engine batteries
when such are provided. Where one auxiliary engine is arranged for electric starting, one battery
(or set) may be accepted in lieu of two separate batteries (or sets). The capacity of the batteries for
starting the auxiliary engines is to be sufficient for at least three starts for each engine.
13.9.3 Other Requirements
The starting batteries (or set of batteries) are to be used for starting and for engine’s own control
and monitoring purpose only. When the starting batteries are used for engine’s own control and
monitoring purpose, the aggregate capacity of the batteries is to be sufficient for continued operation
of such system in addition to the required number of starting capacity. Provisions are to be made
to continuously maintain the stored energy at all times. See also 4-6-2/5.19 and 4-6-3/3.7.

13.11 Hydraulic Starting

Hydraulic oil accumulators for starting the main propulsion engines are to have sufficient capacity without
recharging for starting the main engines, as required in 4-2-1/13.3.

22 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

15 Engine Exhaust Systems

15.1 General
The exhaust pipes are to be water-jacketed or effectively insulated. Engine exhaust systems are to be so
installed that the vessel’s structure cannot be damaged by heat from the systems. Exhaust pipes of several
engines are not to be connected together but are to be run separately to the atmosphere unless arranged to
prevent the return of gases to an idle engine. Exhaust lines which are led overboard near the waterline are
to be protected against the possibility of the water finding its way inboard.

15.3 Exhaust System Materials

Materials used in the exhaust system are to be resistant to saltwater corrosion, galvanically compatible to
each other and resistant to exhaust products. Plate flanges will be considered where the specified material
is suitable for exhaust piping pressures and temperatures.

15.5 Exhaust Gas Temperature

Propulsion engines with bores exceeding 200 mm (7.87 in.) are to be fitted with a means to display the
exhaust gas temperature of each cylinder.

17 Couplings

17.1 Flexible Shaft Couplings

Details of the various components of flexible couplings for main propulsion machinery and ship’s service
generator sets are to be submitted for approval. Flexible couplings with elastomer or spring type flexible
members and which represent the sole source of transmitting propulsive power in a line shaft on a single
screw vessel are to be provided with torsional limit capacity (coupling will lock beyond its limit) or positive
means of locking the coupling. Operation of the vessel with a locked coupling may be at reduced power,
provided warning notices are posted at the control station.

17.3 Flanged Couplings and Coupling Bolts

Refer to 4-3-1/19.5 for flanged couplings.
Elongation for auxiliary machinery coupling bolts made of steel having an ultimate tensile strength over
690 N/mm2 (70 kgf/mm2, 100,000 psi) will be subject to special consideration. Also refer to 4-3-1/19.1 and
4-3-1/19.3.

19 Testing of Pumps Associated with Engine and Reduction Gear

Operation
Pumps associated with engine and reduction gear operation (oil, water, fuel) utilized with engines having
bores exceeding 300 mm (11.8 in.) are to be provided with certificates issued by the Surveyor. The following
tests are to be conducted to the Surveyor’s satisfaction:

19.1 Pumps Hydrostatic Tests

Independently-driven pumps are to be hydrostatically tested to 4 bar (4 kgf/cm2, 57 psi), but not less than
1.5P, where P is the maximum working pressure in the part concerned.

19.3 Capacity Tests

Tests of pump capacities are to be conducted to the satisfaction of the Surveyor with the pump operating at
design conditions. Capacity tests will not be required for individual pumps produced on a production line
basis, provided the Surveyor is satisfied from periodic inspections and the manufacturer’s quality assurance
procedures that the pump capacities are acceptable.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 23
Part 4 Vessel Systems and Machinery
Chapter 2 Prime Movers
Section 1 Internal Combustion Engines and Reduction Gears 4-2-1

21 Trial
Before final acceptance, the entire installation is to be operated in the presence of the Surveyor to
demonstrate its ability to function satisfactorily under operating conditions and its freedom from harmful
vibration at speeds within the operating range. See also 4-1-1/33.
For conventional propulsion gear units above 1120 kW (1500 HP), a record of gear-tooth contact is to be
made at the trials. To facilitate the survey of extent and uniformity of gear-tooth contact, selected bands of
pinion or gear teeth on each meshing are to be coated beforehand with copper or layout dye. See 7-6-2/1.1.2.
The gear-tooth examination for conventional gear units 1120 kW (1500 HP) and below and all epicyclic gear
units will be subject to special consideration. The gear manufacturer’s recommendations will be considered.

24 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Chapter 3: Propulsion and Maneuvering Machinery

4
CHAPTER 3 Propulsion and Maneuvering Machinery

CONTENTS
SECTION 1 Propulsion Shafting ............................................................................. 29
1 General .............................................................................................29
3 Plans and Data to be Submitted .......................................................29
5 Materials and Testing........................................................................29
5.1 Material.......................................................................................... 29
5.3 Material Tests................................................................................ 29
5.5 Inspection ...................................................................................... 30
5.7 Weldability ..................................................................................... 30
7 Design and Construction...................................................................30
7.1 Shaft Diameters............................................................................. 30
7.3 Hollow Shafts ................................................................................ 32
9 Key ....................................................................................................32
11 Tail Shaft Liners ................................................................................33
11.1 Thickness at Bearings ................................................................... 33
11.3 Thickness Between Bearings ........................................................ 33
11.5 Continuous Fitted Liners................................................................ 33
11.7 Fit Between Bearings .................................................................... 33
11.9 Material and Fit.............................................................................. 33
11.11 Glass Reinforced Plastic Coating .................................................. 34
11.13 Stainless Steel Cladding................................................................ 34
13 Tail Shaft Bearings............................................................................34
13.1 Water Lubricated Bearings ............................................................ 34
13.3 Oil Lubricated Bearings ................................................................. 34
15 Tail Shaft Propeller End Design........................................................35
15.1 Keyed ............................................................................................ 35
15.3 Keyless.......................................................................................... 35
17 Flexible Couplings.............................................................................35
19 Solid Couplings .................................................................................35
19.1 Fitted Bolts .................................................................................... 35
19.3 Non-fitted Bolts.............................................................................. 36
19.5 Flanges.......................................................................................... 36
19.7 Demountable Couplings ................................................................ 36
21 Propulsion Shaft Alignment and Vibration ........................................37
21.1 General.......................................................................................... 37
21.3 Vessels 61 m (200 ft) in Length and Over ..................................... 37
21.5 Vessels Below 61 m (200 ft) in Length .......................................... 37

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 25
 TABLE 1 Shaft Design Factor K for Line Shafts, Thrust Shafts, and
Oil Distribution Shafts..............................................................31
TABLE 2 Shaft Design Factor K for Tail Shafts and Stern Tube
Shafts ......................................................................................32

SECTION 2 Propellers.............................................................................................. 38
1 General .............................................................................................38
3 Small Conventional Propellers..........................................................38
5 Plans and Data to be Submitted .......................................................38
5.1 Fixed-Pitch Propellers....................................................................38
5.3 Controllable-Pitch Propellers .........................................................38
7 Materials and Testing........................................................................38
7.1 Propeller Material...........................................................................38
7.3 Stud Materials................................................................................39
7.5 Material Testing .............................................................................39
9 Blade Design.....................................................................................39
9.1 Blade Thickness ............................................................................39
9.3 Blades of Unusual Design .............................................................41
9.5 Blade-root Fillets............................................................................41
9.7 Built-up Blades ..............................................................................41
11 Skewed Propeller Blades..................................................................42
11.1 Definitions......................................................................................42
11.3 Application .....................................................................................42
11.5 Propellers Over 25° up to 50° Skew Angle ....................................42
13 Studs .................................................................................................43
13.1 Stud Area.......................................................................................43
13.3 Fit of Studs and Nuts .....................................................................44
15 Blade Flange and Mechanisms.........................................................44
17 Controllable Pitch Propeller System .................................................44
17.1 Blade Pitch Control ........................................................................44
17.3 Instrumentation and Alarms...........................................................45
17.5 Electrical Components...................................................................45
19 Propeller Fitting.................................................................................45
19.1 Keyed Fitting..................................................................................45
19.3 Keyless Fitting ...............................................................................45
21 Protection Against Corrosion ............................................................48
21.1 Propeller Aft End............................................................................48
21.3 Propeller Forward End...................................................................49
21.5 Noncorrosive, Non-pitting Alloys....................................................49

TABLE 1 Propeller Materials ..................................................................39

FIGURE 1 Maximum Skew Angle ............................................................43

FIGURE 2 Rake Angle at the 0.6 Radius, Positive Aft .............................43
FIGURE 3 Keyless Propeller – Theoretical Contact Surface Area
Between Propeller Boss and Shaft .........................................48
FIGURE 4 Propeller Hub Details ..............................................................49

26 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 SECTION 3 Steering Gear........................................................................................ 50
1 General .............................................................................................50
1.1 Application..................................................................................... 50
1.3 Definitions...................................................................................... 50
1.5 Plans and Data.............................................................................. 51
1.7 Power Operation ........................................................................... 51
1.9 Main Steering Gear ....................................................................... 51
1.11 Auxiliary Steering Gear.................................................................. 51
1.13 Steering Gear Compartment Unit Location.................................... 52
3 Materials............................................................................................52
3.1 General.......................................................................................... 52
3.3 Material Testing............................................................................. 52
5 Design ...............................................................................................53
5.1 Power Gear Stops ......................................................................... 53
5.3 Mechanical Components ............................................................... 53
5.4 Steering Gear Torque.................................................................... 53
5.5 Tiller .............................................................................................. 54
5.7 Pin ................................................................................................. 55
5.9 Tie Rod (Jockey Bar)..................................................................... 55
5.11 Rudder Actuators .......................................................................... 55
5.13 Mechanical Steering Gear ............................................................. 56
7 Hydraulic System ..............................................................................56
7.1 Pipes, Valves and Fittings ............................................................. 56
7.3 Relief Valves ................................................................................. 56
7.5 Filtration......................................................................................... 57
7.7 Single Failure ................................................................................ 57
7.9 Reservoir and Storage Tank.......................................................... 57
9 Power Units.......................................................................................57
9.1 Prototype Test ............................................................................... 57
9.3 Production Unit Test...................................................................... 57
11 Steering Gear Control System ..........................................................58
11.1 Locations of Control ...................................................................... 58
11.3 Control System Segregation.......................................................... 58
11.5 Control System Power Supply....................................................... 58
11.7 Communication ............................................................................. 58
11.9 Instrumentation and Alarms........................................................... 59
11.11 Operating Instructions ................................................................... 60
13 Electrical Power Supply ....................................................................60
15 Testing and Trials .............................................................................61
15.1 Testing of Piping System............................................................... 61
15.3 Trials ............................................................................................. 61

SECTION 4 Waterjets ............................................................................................... 62

1 Waterjets ...........................................................................................62
1.1 General.......................................................................................... 62
1.3 Design ........................................................................................... 62
1.5 Housings ....................................................................................... 62

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 27
 1.7 Reversing Mechanisms .................................................................63
1.9 Impeller Bearings...........................................................................63

SECTION 5 Propulsion Redundancy ...................................................................... 64

1 General .............................................................................................64
1.1 Application .....................................................................................64
1.3 Objective........................................................................................64
1.5 Definitions ......................................................................................64
1.7 Plans and Data to be Submitted ....................................................65
3 Classification Notations.....................................................................65
5 Single Failure Concept......................................................................67
5.1 Single Failure Criteria ....................................................................67
7 Propulsion and Steering Capability...................................................67
7.1 Vessels Without + in Class Notation..............................................67
7.3 Vessels with + in Class Notation....................................................67
9 System Design ..................................................................................67
9.1 Propulsion Machinery and Propulsors ...........................................67
9.3 System Segregation ......................................................................68
9.5 Steering Systems...........................................................................68
9.7 Auxiliary Service Systems .............................................................68
9.9 Electrical Distribution Systems ......................................................69
9.11 Control and Monitoring Systems....................................................69
9.13 Communication Systems ...............................................................70
11 Fire Precautions................................................................................70
13 Operating Manual .............................................................................70
15 Test and Trial ....................................................................................71
15.1 Fault Simulation Test .....................................................................71
15.3 Communication System Test.........................................................71
17 Survey After Construction .................................................................71

FIGURE 1 Arrangements of Propulsion Redundancy ..............................66

28 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 1: Propulsion Shafting

4
CHAPTER 3 Propulsion and Maneuvering Machinery

SECTION 1 Propulsion Shafting

1 General
The construction of the propellers and propulsion shafting for vessels is to be carried out in accordance
with the following requirements and to the satisfaction of the Surveyor. For vessels distinguished in the
Record by the words “Ice Class”, see Part 6, Chapter 1 of the Steel Vessel Rules.

3 Plans and Data to be Submitted

Plans and specifications are to be submitted in accordance with 4-1-1/7.19, as indicated in the following:
Detailed plans together with material specifications of the propulsion shafting, couplings, coupling bolts,
propulsion shafting arrangement, tail shaft bearings and lubrication system, if oil-lubricated, are to be
submitted. Calculations are to be included for flexible couplings and demountable couplings. See 4-2-1/17
and 4-3-1/19.7. See also 4-3-1/21.

5 Materials and Testing

5.1 Material (2004)

Materials for propulsion shafts, couplings and coupling bolts, keys and clutches are to be of forged steel or
rolled bars, as appropriate, in accordance with Section 2-3-7 and Section 2-3-8 of the ABS Rules for
Materials and Welding (Part 2) or other specifications as may be specially approved with a specific design.
Where materials other than those specified in the Rules are proposed, full details of chemical composition,
heat treatment and mechanical properties, as appropriate, are to be submitted for approval.
5.1.1 Ultimate Tensile Strength
In general, the minimum specified ultimate tensile strength of steel used for propulsion shafting is
to be between 400 N/mm2 (40.7 kgf/mm2, 58,000 psi) and 930 N/mm2 (95.0 kgf/mm2, 135,000 psi).
5.1.2 Elongation
Material with elongation (Lo/d = 4) of less than 16% is not to be used for any shafting component,
with the exception that material for non-fitted alloy steel coupling bolts manufactured to a recognized
standard may have elongation of not less than 10%.

5.3 Material Tests

5.3.1 General
Materials for all torque-transmitting parts, including shafts, clutches, couplings, coupling bolts and
keys are to be tested in the presence of the Surveyor. The materials are to meet the specifications
of 2-3-7/5. 2-3-7/7 and 2-3-8/1 of the ABS Rules for Materials and Welding (Part 2) or other
specifications approved in connection with the design.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 29
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

5.3.2 Alternative Test Requirements

Materials for shafting, couplings and coupling bolts transmitting 373 kW (500 HP) or less will be
accepted based on the manufacturer’s certified mill tests and hardness check witnessed by the
Surveyor. Bolts manufactured to a recognized standard and used as coupling bolts will not require
material testing.

5.5 Inspection
Shafting and couplings are to be surface-examined at the manufacturer. Tail shafts in the finished machine
condition are to be subjected to a nondestructive examination such as magnetic particle, dye penetrant or
other nondestructive methods and are to be free of linear discontinuities greater than 3.2 mm (1/8 in.),
except that in the following locations, the shafts are to be free of all linear discontinuities:
5.5.1 Tapered Tail Shafts
The forward one-third length of the taper, including the forward end of any keyway and an equal
length of the parallel part of the shaft immediately forward of the taper.
5.5.2 Flanged Tail Shafts
The flange fillet area.

5.7 Weldability (2008)

Steel used for tail shafts is to have carbon content in accordance with 2-3-7/1.1.2 of the ABS Rules for
Materials and Welding (Part 2).

7 Design and Construction (2004)

7.1 Shaft Diameters (2010)

The least diameter of propulsion shafting is to be determined by the following equation:

D = 100K 3 ( H R)[c1 (U + c 2 )]

where
c1 = 560 (41.95, 3.695) for vessels 45.7 m (150 ft) in length and over
= 472.5 (35.4, 3.12) for vessels 20 m (65 ft) and over, but below 45.7 m (150 ft),
where the material of the shaft is Grade 2 and the shaft is
protected
= 540 (40.3, 3.55) for vessels 20 m (65 ft) and over, but below 45.7 m (150 ft), for
all other materials and unprotected Grade 2 shaft material
= 416.4 (31.22, 2.75) for vessels below 20 m (65 ft)
c2 = 160 (16.3, 23180)
D = required shaft diameter, in mm (in.), for all shafts, except those covered in 4-3-1/9.
K = shaft design factor (see 4-3-1/Table 1 and 4-3-1/Table 2)
H = power at rated speed, kW (PS, HP), [(MKS units: 1 PS = 0.735 kW),
(US units: 1 HP = 0.746 kW)]
R = rpm at rated speed

30 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

U = minimum specified ultimate tensile strength of the material, in N/mm2 (kgf/mm2, psi).
For calculation purposes, U is not to be taken as more than the following:
= 415 N/mm2 (42.2 kgf/mm2, 60,000 psi) for carbon, and alloy steel tail shafts fitted
with salt-water lubricated bearings and non-continuous shaft liners.
= 600 N/mm2 (61.2 kgf/mm2, 87,000 psi) for carbon, alloy and austenitic stainless steel
tail shafts fitted with oil lubricated bearings or with continuous shaft liners or
equivalent.
= 930 N/mm2 (95.0 kgf/mm2, 135,000 psi) for other shaft sections and for tail shafts
manufactured of age-hardened martensitic stainless steels, higher-strength austenitic
stainless steels such as ASTM Type XM-19, XM-21, or XM-28, or other high
strength alloy materials.
Note: In general, the minimum specified ultimate tensile strength of steel used for propulsion shafting is to be
between 400 N/mm2 (40.7 kgf/mm2, 58,000 psi) and 930 N/mm2 (95.0 kgf/mm2, 135,000 psi). See also
4-3-1/5.1.

TABLE 1
Shaft Design Factor K for Line Shafts, Thrust Shafts, and Oil Distribution Shafts
Design Features (1)
In way of
Axial
Radial On Both Bearings
Holes, Sides of used as
Integral Shrink Fit Transverse Longitudinal Thrust Thrust Straight
Propulsion Type Flange Coupling Keyways (2) Holes (3) Slots (4) Collars Bearings Sections
Turbine
Electric Drives
Diesel Drives
through slip 0.95 0.95 1.045 1.045 1.14 1.045 1.045 0.95
couplings
(electric or
hydraulic)
All Other Diesel
1.0 1.0 1.1 1.1 1.2 1.1 1.1 1.0
Drives
Notes:
1 Geometric features other than those listed will be specially considered
2 After a length of not less than 0.2D from the end of the keyway, the shaft diameter may be reduced to the diameter
calculated for straight sections.
Fillet radii in the transverse section of the bottom of the keyway are to be not less than 0.0125D
3 Diameter of bore not more than 0.3D
4 Length of the slot not more than 1.4D, width of the slot not more than 0.2D, whereby D is calculated with k = 1.0

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 31
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

TABLE 2
Shaft Design Factor K for Tail Shafts and Stern Tube Shafts (See Note 1)
Propeller Attachment Method (2)
Stern Tube Keyless Attachment
Propulsion Type Configuration Keyed (3) by Shrink Fit (4) Flanged (5) Stern Tube Shafts (7, 8)
All Oil-lubricated bearings 1.26 1.22 1.22 1.15
All Water-lubricated 1.26 1.22 1.22 1.15
bearings with
continuous shaft
liners or equivalent
All Water-lubricated 1.29 1.25 1.25 1.18
bearings with non-
continuous
shaft liners(6)
Notes:
1 The tail shaft diameter may be reduced to the stern tube shaft diameter forward of the bearing supporting
the propeller, and the stern tube shaft diameter reduced to the line shaft diameter inboard of the forward
stern tube seal. The inboard end of tail shafts or tube shafts within the vessel, as applicable, is to be
designed the same as line shafts, with shaft design factors in accordance with 4-3-1/Table 1.
2 Other attachments are subject to special consideration.
3 Fillet radii in the transverse section at the bottom of the keyway are not to be less than 0.0125D.
4 See also 4-3-1/15.
5 The fillet radius in the base of the flange for the tail shaft supporting the propeller is to be at least 0.125D.
Special consideration will be given to fillets of multiple radii design. The fillet radius is to be accessible
for nondestructive examination during tail shaft surveys. See 7-5-1/3 and Section 7-5-2 of the ABS
Rules for Survey After Construction (Part 7). For other fillet radii, see 4-3-1/19.5.
6 For Great Lakes service, K factor corresponding to continuous liner configuration may be used.
7 K factor applies to shafting between the forward edge of the propeller-end bearing and the inboard stern
tube seal.
8 Where keyed couplings are fitted on stern tube shaft, the shaft diameters are to be increased by 10% in
way of the coupling. See Note 2 of 4-3-1/Table 1.

7.3 Hollow Shafts

For hollow shafts where the bore exceeds 40% of the outside diameter, the minimum shaft diameter is not
to be less than that given by the following equation:

Do = D 3 1 /[1 − ( Di / Do ) 4 ]

where
Do = required outside diameter, in mm (in.)
D = solid shaft diameter required by 4-3-1/7, as applicable, in mm (in.)
Di = actual shaft bore, in mm (in.)

9 Key (2004)
In general, the key material is to be of equal or higher strength than the shaft material. The effective area of
the key in shear is to be not less than A, given below. The effective area is to be the gross area subtracted
by materials removed by saw cuts, set screw holes, chamfer, etc., and is to exclude the portion of the key in
way of spooning of the key way.

32 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

D 3 YS
A= ⋅
5.1rm YK
where
A = shear area of key, mm2 (in2)
D = line shaft diameter, mm (in.), as determined by 4-3-1/7.1
rm = shaft radius at mid-length of the key, mm (in.)
YS = specified yield strength of shaft material, N/mm2 (kgf/mm2, psi)
YK = specified yield strength of key material, N/mm2 (kgf/mm2, psi)

11 Tail Shaft Liners

11.1 Thickness at Bearings (2009)

11.1.1 Bronze Liner
The thickness of bronze liners to be fitted to tail shafts or tube shafts is not to be less than that
given by the following equation:
t = T/25 + 5.1 mm t = T/25 + 0.2 in.
where
t = thickness of liner, in mm (in.)
T = required diameter of tail shaft, in mm (in.)
11.1.2 Stainless Steel Liner
The thickness of stainless steel liners to be fitted to tail shafts or tube is not to be less than one-half
that required for bronze liners or 6.5 mm (0.25 inches), whichever is greater.

11.3 Thickness Between Bearings

The thickness of a continuous bronze liner between bearings is to be not less than three-fourths of the
thickness, t, determined by the foregoing equation.

11.5 Continuous Fitted Liners

Continuous fitted liners are to be in one piece or, if made of two or more lengths, the joining of the separate
pieces is to be done by an approved method of fusion through not less than two-thirds the thickness of the
liner or by an approved rubber seal.

11.7 Fit Between Bearings

If the liner does not fit the shaft tightly between the bearing portions, the space between the shaft and liner
is to be filled by pressure with an insoluble, non-corrosive compound.

11.9 Material and Fit

Fitted liners are to be of a high-grade composition, bronze or other approved alloy, free from porosity and
other defects, and are to prove tight under hydrostatic test of 1.0 bar (1 kgf/cm2, 15 psi). All liners are to be
carefully shrunk or forced upon the shaft by pressure and they are not to be secured by pins.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 33
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

11.11 Glass Reinforced Plastic Coating

Glass reinforced plastic coatings may be fitted on propulsion shafting when applied by an approved
procedure to the satisfaction of the Surveyor. Such coatings are to consist of at least four plies of cross-
woven glass tape impregnated with resin, or an equivalent process. Prior to coating, the shaft is to be
cleaned with a suitable solvent and grit-blasted. The shaft is to be examined prior to coating and the first
layer is to be applied in the presence of the Surveyor. Subsequent to coating, the finished shaft is to be
subjected to a spark test or equivalent to verify freedom from porosity to the satisfaction of the Surveyor.
In all cases where reinforced plastic coatings are employed, effective means are to be provided to prevent
water having access to the shaft. Provisions are to be made for overlapping and adequately bonding the
coating to fitted or clad liners. The end of the liner is to be stepped and tapered as required to protect the
end of the wrapping.

11.13 Stainless Steel Cladding

Stainless steel cladding of shafts is to be carried out in accordance with an approved procedure. See
Appendix, Section 11, “Guide for Repair and Cladding of Shafts” of the Rules for Survey After Construction
(Part 7).

13 Tail Shaft Bearings

13.1 Water Lubricated Bearings

13.1.1 Wood Bearings (resinous, dense hardwoods)
The length of the bearing next to and supporting the propeller is to be not less than four times the
required tail shaft diameter.
13.1.2 Synthetic Bearings (rubber, reinforced resins, plastic materials)
The length of the bearing next to and supporting the propeller is to be not less than four times the
required tail shaft diameter.
For a bearing design substantiated by experimental tests to the satisfaction of ABS, consideration
may be given to a bearing length of less than four times, but not less than two times, the required
tail shaft diameter.

13.3 Oil Lubricated Bearings

13.3.1 White Metal Lined
The length of white-metal lined, oil-lubricated propeller-end bearings fitted with an approved oil-
seal gland is to be on the order of two times the required tail shaft diameter. The length of the bearing
may be less, provided the nominal bearing pressure is not more than 0.80 N/mm2 (0.0815 kgf/mm2,
116 psi) as determined by static bearing reaction calculation taking into account shaft and propeller
weight which is deemed to be exerted solely on the aft bearing, divided by the projected area of
the shaft. The minimum length, however, is not to be less than 1.5 times the actual diameter.
13.3.2 Synthetic Bearings (rubber, reinforced resins, plastic etc.)
The length of synthetic rubber, reinforced resin or plastic oil-lubricated propeller end bearings fitted
with an approved oil-seal gland is to be on the order of two times the required tail shaft diameter.
The length of the bearing may be less, provided the nominal bearing pressure is not more than
0.60 N/mm2 (0.0611 kgf/mm2, 87 psi), as determined by static bearing reaction calculation taking
into account shaft and propeller weight which is deemed to be exerted solely on the aft bearing,
divided by the projected area of the shaft. The minimum length, however, is not to be less than 1.5
times the actual diameter. Where the material has demonstrated satisfactory testing and operating
experience, consideration may be given to increased bearing pressure.

34 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

15 Tail Shaft Propeller End Design

Tail shafts are to be provided with an accurate taper fit in the propeller hub, particular attention being given to
the fit at the large end of the taper.

15.1 Keyed (1998)

The key is to fit tightly in the keyway and be of sufficient size to transmit the full torque of the shaft, but it
is not to extend into the liner counterbore on the forward side of the hub. The forward end of the keyway is
to be so cut in the shaft as to give a gradual rise from the bottom of the keyway to the surface of the shaft.
Ample fillets are to be provided in the corners of the keyway and, in general, stress concentrations are to
be reduced as far as practicable.

15.3 Keyless (1998)

Where propellers are fitted without keys, detailed stress calculations and fitting instructions are to be
submitted for review. See 4-3-2/19.

17 Flexible Couplings
See 4-2-1/17.1.

19 Solid Couplings

19.1 Fitted Bolts (2008)

The minimum diameter of fitted shaft coupling bolts is to be determined by the following equation.

db = 0.65 D 3 (U + c) / NBU b mm (in.)

where
db = diameter of bolts at joints, in mm (in.)
D = minimum required shaft diameter designed considering the largest combined torque
(static and dynamic), acting at the shaft in vicinity of the respective coupling flanges;
mm (in), see 4-3-1/21, but not less than the minimum required line shaft diameter, as
per 4-3-1/7, in mm (in.)
U = minimum specific tensile strength of shaft material, in N/mm2, (kgf/mm2, psi)
c = 160 (16.3, 23180)
N = number of bolts fitted in one coupling
B = bolt circle diameter, in mm (in.)
Ub = minimum specific tensile strength of bolt material, in N/mm2, (kgf/mm2, psi). To be
not less than U. Ub, is to be taken not more than 1.7U or 1000 N/mm2 (102 kgf/mm2,
145,000 psi), whichever is less, for calculation purposes.
Notes: (2008)
1 The bolts are to be assembled with an interference fit.
2 The use of other materials will be subject to special consideration based on submitted engineering
analyses.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 35
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

19.3 Non-fitted Bolts

The diameter of pre-stressed, non-fitted coupling bolts will be considered upon the submittal of detailed
preloading and stress calculations and fitting instructions. The tensile stress on the bolt due to pre-stressing
and astern pull is not to exceed 90% of the minimum specified yield strength of the bolt material. In
addition, the bearing stress on any member such as the shaft, bolt, threads or nut is not to exceed 90% of
the minimum specified yield strength of the material for that member.
19.3.1 Power Transmitted by Prestress Only
Where bolts are under pure tension, the factor of safety against slip under the worst of the operating
conditions, including mean transmitted torque plus vibratory torque due to torsional loads, is to be
at least as follows:
i) Inaccessible couplings (external to the hull or not readily accessible) 2.8
ii) Accessible couplings (internal to the hull) 2.0
19.3.2 Power Transmitted by Combination Prestress and Shear
Where the power is transmitted by a combination of fitted bolts and pre-stressed, non-fitted bolts,
the components are to meet the following criteria:
19.3.2(a) Fitted Bolts. The shear stress under the maximum torque corresponding to the worst
loaded condition is to be not more than 50% of the minimum specified tensile yield strength of the
bolt material.
19.3.2(b) Non-Fitted Bolts. The factor of safety against slip under the maximum torque
corresponding to the worst loaded condition and the specified bolt tension is to be at least 1.6 for
inaccessible couplings and 1.1 for accessible couplings.
19.3.3 Dowels Used for Transmitting Power
Dowels connecting the tail shaft flange to the controllable pitch propeller hub, utilized with non-
fitted bolts to transmit power, are considered equivalent to fitted coupling bolts and are to comply
with 4-3-1/19.1 and, if applicable, 4-3-1/19.3.2(a). The dowels are to be accurately fitted and
effectively secured against axial movement. The coupling is to be satisfactory for astern condition.

19.5 Flanges
The thickness of coupling flanges is not to be less than the minimum required diameter of the coupling
bolts or 0.2 times D (as defined in 4-3-1/7), whichever is greater. The fillet radius at the base of an integral
flange is not to be less than 0.08 times the actual shaft diameter. Consideration of a recognized shaft coupling
standard will be given to fillets of multiple radii design. In general, the surface finish for fillet radii is not
to be rougher than 1.6 μmeters (63 μin.) RMS. For the fillet radius for tail shaft to propeller coupling flange,
see Note 4 in 4-3-1/Table 2.

19.7 Demountable Couplings

Couplings are to be made of steel or other approved ductile material. The strength of demountable couplings
and keys is to be equivalent to that of the shaft. Couplings are to be accurately fitted to the shaft. Where
necessary, provisions for resisting thrust loading are to be provided.
Hydraulic and other shrink fit couplings will be specially considered upon submittal of detailed preloading
and stress calculations and fitting instructions. In general, the torsional holding capacity is to be at least 2.8
times the transmitted mean torque plus vibratory torque due to torsionals for inaccessible couplings
(external to the hull or not readily accessible) and at least 2.0 times for accessible couplings (internal to the
hull). The preload stress is not to exceed 70% of the minimum specified yield strength.

36 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 1 Propulsion Shafting 4-3-1

21 Propulsion Shaft Alignment and Vibration

21.1 General
Propulsion shafting is to be aligned with the location and spacing of the shaft bearings, being such as to
give acceptable bearing reactions and shaft bending moments and also acceptable amplitudes of vibration
for all conditions of vessel loading and operation.
The designer or the builder is to evaluate the propulsion shafting system, taking into consideration any
forces or factors which may affect the reliability of the propulsion shafting system, including weight of the
propeller and shafts, hydrodynamic forces acting on the propeller, number of propeller blades in relation to
diesel engine cylinders, misalignment forces, thermal expansion, flexibility of engine and thrust bearing
foundations, engine induced vibrations, gear tooth loadings, flexible couplings, effect of power take-off
arrangements from the propulsion shafting system driving auxiliaries, etc., as applicable, as well as any
limits for vibrations and loadings specified by the equipment manufacturers.

21.3 Vessels 61 m (200 ft) in Length and Over

21.3.1 Shaft Alignment Calculations
The requirements in 4-3-2/7.3 of the Steel Vessel Rules are to be complied with.
21.3.2 Torsional Vibrations
The requirements in 4-3-2/7.5.1 of the Steel Vessel Rules are to be complied with.
21.3.3 Axial Vibrations
The requirements in 4-3-2/7.7 of the Steel Vessel Rules are to be complied with.
21.3.4 Lateral (Whirling) Vibrations
The requirements in 4-3-2/7.9 of the Steel Vessel Rules are to be complied with.
21.3.5 Cast Resin Chocks (2009)
Resin chocks and their installation are to comply with the requirements in 4-3-2/11.1.2 of the Steel
Vessel Rules.

21.5 Vessels Below 61 m (200 ft) in Length

21.5.1 Torsional Vibration
For vessels fitted with an unusual propulsion arrangement or without vibration dampers, a torsional
vibration analysis of the propulsion system showing compliance with 4-3-2/7.5.1 of the Steel
Vessel Rules is to be submitted. This is not required for vessels under 20 m (65 ft) in length or
where the installation is essentially the same as previous designs which have been proven satisfactory.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 37
PART Section 2: Propellers

4
CHAPTER 3 Propulsion and Maneuvering Machinery

SECTION 2 Propellers

1 General
The construction of the propellers and propulsion shafting for vessels is to be carried out in accordance
with the following requirements and to the satisfaction of the Surveyor. Upon satisfactory compliance with
the requirements, a notation will be made in the Record indicating the type of propeller and the material of
which it is made. See Part 6, Chapter 1 of the Steel Vessel Rules for vessels assigned an Ice Class notation.

3 Small Conventional Propellers

For planing and semi-planing vessels, the propellers need not to be designed and constructed in accordance
with these requirements, provided they do not exceed 1.5 m (60 in.) in diameter and are part of a manufacturer’s
standard product line. In such instances, neither the Surveyor’s attendance for the material testing and inspection
nor the design review will be required.

5 Plans and Data to be Submitted

Plans and specifications are to be submitted in accordance with 4-1-1/7.15, as indicated in the following:

5.1 Fixed-Pitch Propellers

Where the propeller blades are of conventional design, a propeller plan giving the design data and characteristics
of the material, as required by 4-3-2/9.1, is to be submitted. For skewed propellers or propeller blades of
unusual design, a detailed stress analysis is also to be submitted as required by 4-3-2/9.3 or 4-3-2/11.3. For
keyless propellers, see 4-3-2/19.3.

5.3 Controllable-Pitch Propellers

In addition to the plan and data required in 4-3-2/5.1 for the propeller blade, plans of the propeller hub,
propeller blade flange and bolts, internal mechanisms, hydraulic piping control systems, and instrumentation
and alarm system are to be submitted. Strength calculations are to be included for the internal mechanism.
See 4-3-2/15.

7 Materials and Testing (2011)

7.1 Propeller Material

For propellers required to be of an approved design, 4-3-2/Table 1 shows the properties of materials
normally used for propellers. See 2-3-14/3 and Section 2-3-15 of the ABS Rules for Materials and Welding
(Part 2) for full details of the materials.
Where an alternative material specification is proposed, detailed chemical composition and mechanical
properties are to be submitted for approval (for example, see Sections 2-3-14 and 2-3-15 of the above referenced
Part 2). The f and w values of such materials to be used in the equations hereunder will be specially considered
upon submittal of complete material specifications including corrosion fatigue data to 108 cycles.

38 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

TABLE 1
Propeller Materials (2011)
Elongation, %
Tensile Strength Yield Strength Gauge Length
2 2 2 2 2 2
Type Material N/mm kgf/mm lb/in N/mm kgf/mm lb/in 4d 5d
2 Manganese bronze 450 46 65,000 175 18 25,000 20 18
3 Nickel-manganese 515 53 75,000 220 22.5 32,000 18 16
bronze
4 Nickel-aluminum 590 60 86,000 245 25 36,000 16 15
bronze
5 Manganese-nickel- 630 64 91,000 275 28 40,000 20 18
aluminum bronze
CF-3 Stainless steel 485 49 70,000 205 21 30,000 35 32

7.3 Stud Materials

The material of the studs securing detachable blades to the hub is to be of at least Grade 2 forged steel or
equally satisfactory material; see 2-3-7/7 of the ABS Rules for Materials and Welding (Part 2) for specifications
of Grade 2 forged steel.

7.5 Material Testing

Materials of propellers cast in one piece and materials of blades, hub, studs and other load-bearing parts of
controllable pitch propellers are to be tested in the presence of a Surveyor. For requirements of material
testing, see 2-3-7/7, 2-3-14/3, and Section 2-3-15 of the ABS Rules for Materials and Welding (Part 2).

9 Blade Design

9.1 Blade Thickness

Where the propeller blades are of conventional design, the thickness of the blades is not to be less than
determined by the following equations:
9.1.1 Fixed-Pitch Propellers
⎡ AH ⎛ C ⎞ ⎛ BK ⎞⎤
t 0.25 = S ⎢ K 1 ± ⎜⎜ s ⎟⎟ ⎜ ⎟⎥ mm (in.)
⎣⎢ C n CRN ⎝ C n ⎠ ⎝ 4C ⎠⎦⎥

where
A = 1.0 + (6.0/P0.70) + 4.3P0.25

B = (4300wa/N) (R/100)2(D/20)3
C = (1 + 1.5P0.25)(Wf − B)

S = 1.0. for all propellers with D ≤ 6.1 m (20 ft)

= ( D + 24.0) / 30.1 SI, MKS units, or

= ( D + 79) / 99 US units for solid propellers with D > 6.1 m (20 ft). S is
not to exceed 1.025.
t0.25 = required thickness at the one-quarter radius, in mm (in.)
K1 = 337 (289, 13)
H = power at rated speed, kW (hp, HP)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 39
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

hp = metric horsepower
HP = US horsepower
R = rpm at rated speed
N = number of blades
P0.25 = pitch at one-quarter radius divided by propeller diameter
P0.7 = pitch at seven-tenths radius divided by propeller diameter, corresponding to
the design ahead conditions
W = expanded width of a cylindrical section at the 0.25 radius, in mm (in.)
a = expanded blade area divided by the disc area
D = propeller diameter, in m (ft)
K = rake of propeller blade, in mm (in.) (positive for aft rake and negative for
forward rake)
Cs = as/WT (section area coefficient at the 0.25 or 0.35 radius). Also see below.
Cn = Io/UfWT2 (section modulus coefficient at the 0.25 or 0.35 radius). Also see
below.
Io = moment of inertia of the expanded cylindrical section at 0.25 or 0.35 radius
about a straight line through the center of gravity parallel to the pitch line or
to the nose-tail line, in mm4 (in4)
as = area of expanded cylindrical section at the 0.25 or 0.35 radius, in mm2 (in2)
Uf = maximum normal distance from the moment of inertia axis to points on the
face boundary (tension side) of the section, in mm (in.)
T = maximum thickness at the 0.25 or 0.35 radius, in mm (in.), from propeller
drawing
f, w = material constants from the following table:
Representative Propeller Materials SI and MKS Units US Customary Units
Type (See Part 2, Chapter 3) f w f w
2 Manganese bronze 2.10 8.30 68 0.30
3 Nickel-manganese bronze 2.13 8.00 69 0.29
4 Nickel-aluminum bronze 2.62 7.50 85 0.27
5 Mn-Ni-AI bronze 2.37 7.50 77 0.27
Cast steel 2.10 8.30 68 0.30
CF-3 Austenitic stainless steel 2.10 7.75 68 0.28
Note: The f values of materials not covered will be specially considered upon submittal of complete material
specifications including corrosion fatigue data to 108 cycles.

The values of Cs and Cn, computed as stipulated above, are to be indicated on the propeller
drawing. If the Cn value exceeds 0.10, the required thickness is to be computed with Cn = 0.10.
For vessels below 61 m (200 ft) in length, the required thickness may be computed with the assumed
values of Cn = 0.10 and Cs = 0.69.

40 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

9.1.2 Controllable-Pitch Propellers

AH ⎛ C ⎞ ⎛ BK ⎞
t 0.35 = K 2 ± ⎜⎜ s ⎟⎟ ⎜ ⎟ mm (in.)
C n CRN ⎝ C n ⎠ ⎝ 6.3C ⎠

where
A = 1.0 + (6.0/P0.7) + 3P0.35 (free running)
= 7.2 + (2.0/P0.7) + 3P0.35 (bollard, APS, dynamic positioning)

B = (4900wa/N) (R/100)2(D/20)3
C = (1 + 0.6P0.35)(Wf − B)
t0.35 = required thickness at the 0.35 radius, in mm (in.)
K2 = 271 (232, 10.4)
P0.35 = pitch at 0.35 radius divided by propeller diameter, corresponding to the
design ahead conditions
W = expanded width of a cylindrical section at the 0.35 radius, in mm (in.)
H, R, N, P0.7, a, D, K, Cs, Cn, f, and w are as defined in 4-3-2/9.1.1.

9.1.3 Nozzle Propellers (Wide Tip Blades)

⎛ AH ⎞ ⎛ C s ⎞ ⎛ BK ⎞
t 0.35 = K 3 ⎜⎜ ⎟ ±⎜
⎟ ⎜
⎟⎜
⎟ ⎝ 5.6C ⎟⎠ mm (in.)
⎝ C n CRN ⎠ ⎝ C n ⎠
where
A = 1.0 + (6.0/P0.7) + 2.8P0.35 (free running)
= 7.2 + (2.0/P0.7) + 2.8P0.35 (bollard, APS, dynamic positioning)

B = (4625wa/N)(R/100)2(D/20)3
C = (1 + 0.6P0.35)(Wf − B)
t0.35 = required thickness at the 0.35 radius, in mm (in.)
K3 = 288 (247, 11.1)
P0.35 = pitch at 0.35 radius divided by propeller diameter, corresponding to the
design ahead conditions
W = expanded width of a cylindrical section at the 0.35 radius, in mm (in.)
H, R, N, P0.7, a, D, K, Cs, Cn, f, and w are as defined in 4-3-2/9.1.1.

9.3 Blades of Unusual Design

Propellers of unusual design or application will be subject to special consideration upon submittal of
detailed stress calculations.

9.5 Blade-root Fillets

Fillets at the root of the blades are not to be considered in the determination of blade thickness.

9.7 Built-up Blades

The required blade section is not to be reduced in order to provide clearance for nuts. The face of the
flange is to bear on that of the hub in all cases, but the clearance of the spigot in its counterbore or the edge
of the flange in the recess is to be kept to a minimum.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 41
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

11 Skewed Propeller Blades

11.1 Definitions
11.1.1 Maximum Skew Angle
Maximum skew angle (θ) is measured from ray A passing through the tip of blade to ray B tangent
to the mid-chord line of the projected blade outline. See 4-3-2/Figure 1.
11.1.2 Rake Angle
Rake angle (φ) for the purpose of this Subsection is the angle measured from the plane perpendicular
to shaft centerline to the tangent to generating line at 0.6 radius. See 4-3-2/Figure 2.

11.3 Application
11.3.1 θ ≤ 25°
The requirements in 4-3-2/9.1 are applicable where the maximum skew angle is 25 degrees or less.

11.3.2 25° < θ ≤ 50°

The requirements in 4-3-2/11.5 may be used for fixed pitch propellers of ABS Type 4 material
having skew angle over 25 degrees but not exceeding 50 degrees. For other material/type propellers,
calculations as required in 4-3-2/11.3.3 are to be submitted.

11.3.3 θ > 50°

Propellers with the maximum skew angle exceeding 50 degrees will be subject to special consideration
upon submittal of detailed stress calculations.
The maximum stress occurring during steady or transient astern operations is not to exceed seventy
percent of the minimum specified yield strength of the propeller material.

11.5 Propellers Over 25° up to 50° Skew Angle

This paragraph applies to fixed pitch propellers of ABS Type 4 material having a maximum skew angle
over 25 degrees but not exceeding 50 degrees.
11.5.1 Blade Thickness at 0.25 Radius
The maximum thickness at 0.25 radius is not to be less than the thickness required in 4-3-2/9.1.1
multiplied by the factor m, as given below:

m = 1 + 0.0065 (θ − 25)

11.5.2 Blade Thickness at 0.6 Radius

The maximum thickness at 0.6 radius is to be not less than that obtained from the following equation:

t0.6 = K (1 + C 0.9 )(1 + 2C 0.9 / C 0.6 )[( HDΓ) /( RP0.6Y )]0.5

where
t0.6 = required thickness at the 0.6 radius, in mm (in.)
K = 12.6 (6.58, 1.19)
C0.9 = expanded chord length at the 0.9 radius divided by propeller diameter
C0.6 = expanded chord length at the 0.6 radius divided by propeller diameter

Γ = [1 + (θ − 25)/θ][φ2 + 0.16φθP0.9 + 100]

θ = skew angle in degrees (see 4-3-2/11.1.1and 4-3-2/Figure 1)

φ = rake angle in degrees (see 4-3-2/11.1.2 and 4-3-2/Figure 2), positive for rake
aft

42 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

P0.6 = pitch at the 0.6 radius divided by propeller diameter

P0.9 = pitch at the 0.9 radius divided by propeller diameter
Y = minimum specified yield strength of ABS Type 4 propeller material, in
N/mm2 (kgf/mm2, psi)
H, D, R are as defined in 4-3-2/9.1.
11.5.3 Blade Thickness Between 0.6 and 0.9 Radius
11.5.3(a) Maximum Thickness. The maximum thickness between 0.6 and 0.9 radius is not to be
less than that obtained from the following equation.
tx = 3.3D + 2.5(l − x)(t0.6 − 3.3D) mm

tx = 0.04D + 2.5(l − x)(t0.6 − 0.04D) in

where
tx = required maximum blade thickness at radius ratio x
t0.6 = blade thickness at 0.6 radius, as required by 4-3-2/11.5.2

x = ratio of the radius under consideration to D/2, 0.6 < x ≤ 0.9

11.5.3(b) Trailing Edge Thickness at 0.9 Radius. The edge thickness measured at 5% of chord
length from the trailing edge is to be not less than 30% of the maximum blade thickness required
by 4-3-2/11.5.3(a) above at that radius.

FIGURE 1 FIGURE 2
Maximum Skew Angle Rake Angle at the 0.6 Radius, Positive Aft
C D
φ
skew B
A angle θ
0.6
mid-chord radius
The rake angle φ , measured at
line 0.6 radius, is formed between
line D, which is tangent to the
leading generating line, and the line C,
edge which is perpendicular to the
propeller shaft centerline.

13 Studs

13.1 Stud Area

The sectional area of the studs at the bottom of the thread is to be determined by the following equation:

s = 0.056kW t 02.35 f/rn mm2 s = 0.0018kW t 02.35 f/rn in2

where
k = C/(U + C1) material correction factor
C = 621 (63.3, 90,000)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 43
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

C1 = 207 (21.1, 30,000)

U = ultimate tensile strength of the stud material, N/mm2 (kg/mm2, psi)

s = area of one stud at bottom of thread, in mm2 (in2)
n = number of studs on driving side of blade
r = radius of pitch circle of the studs, in mm (in.)
W, f and t0.35 are defined under 4-3-2/9.1.

13.3 Fit of Studs and Nuts

Studs are to be fitted tightly into the hub and provided with effective means for locking. The nuts are also
to have a tight-fitting thread and be secured by stop screws or other effective locking devices.

15 Blade Flange and Mechanisms

The strength of the propeller blade flange and internal mechanisms of controllable-pitch propellers subjected
to the forces from propulsion torque is to be at least 1.5 times that of the blade at design pitch conditions.

17 Controllable Pitch Propeller System

17.1 Blade Pitch Control (2002)

17.1.1 Bridge Control
Where the navigation bridge is provided with direct control of propulsion machinery, it is to be
fitted with means to control the pitch of the propeller.
17.1.2 Duplication of Power Unit
At least two hydraulic power pump units are to be provided for the pitch actuating system and
arranged so that transfer between the pump units can be readily effected. For propulsion machinery
spaces intended for unattended operation (ACCU notation), automatic start of the standby pump
unit is to be provided. The emergency pitch actuating system [as required by 4-3-2/17.1.3iii)] may
be accepted as one of the required hydraulic power pump units, provided it is no less effective.
17.1.3 Emergency Provisions
To safeguard the propulsion and maneuvering capability of the vessel in the event of any single failure
in either the remote pitch control system or the pitch actuating system external to the propeller shaft
and oil transfer device (also known as oil distribution box), the following are to be provided:
i) Manual control of pitch at or near the pitch-actuating control valve (usually the directional
valve or similar).
ii) The pitch is to remain in the last ordered position until the emergency pitch actuating
system is brought into operation.
iii) An emergency pitch actuating system. This system is to be independent of the normal
actuating system up to the oil transfer device, provided with its own oil reservoir and able
to change the pitch from full ahead to full astern.
17.1.4 Integral Oil Systems
Where the pitch actuating hydraulic system is integral with the reduction gear lubricating oil
system and/or clutch hydraulic system, the piping is to be arranged such that any failure in the
pitch actuating system will not leave the other system(s) non-operational.
17.1.5 Provisions for Testing
Means are to be provided in the pitch actuating system to simulate system behavior in the event of
lost of system pressure. Hydraulic pump units driven by main propulsion machinery are to be
fitted with a suitable by-pass for this purpose.

44 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

17.1.6 Multiple Propellers

For vessels fitted with more than one controllable pitch propeller, each of which is independent of
the other, only one emergency pitch actuating system [as required by 4-3-2/17.1.3iii)] need be fitted,
provided it is arranged such that it can be used to provide emergency pitch-changing capability for
all of the propellers.
17.1.7 Hydraulic Piping
Hydraulic piping is to meet the requirements of 4-4-6/1. Testing is to meet the requirements of
4-4-2/3.9.

17.3 Instrumentation and Alarms

The following instruments and alarms are to be provided.
17.3.1 Pitch Indicators
Each station capable of controlling the propeller pitch is to be fitted with a pitch indicator. In addition, a
pitch indicator is to be fitted on the navigation bridge for vessels 500 gross tons and above.
17.3.2 Low Oil Pressure
Visual and audible alarms are to be provided in the engine room control station to indicate low
hydraulic oil pressure.
17.3.3 High Oil Pressure
Visual and audible alarms are to be provided in the engine room control station to indicate high
hydraulic oil pressure. The alarm is to be set below relief valve pressure.
17.3.4 High Temperature
Visual and audible alarms are to be provided in the engine room control station to indicate high
hydraulic oil temperature.

17.5 Electrical Components

Electrical components are to meet the applicable requirements of Part 4, Chapter 6.

19 Propeller Fitting

19.1 Keyed Fitting

For shape of the keyway in the shaft and the size of the key, see 4-3-1/15.1.

19.3 Keyless Fitting (1998)

The formulas specified below apply to the ahead condition, but they will also provide adequate safety
margin for the astern condition. The astern condition is to be considered if the astern torque exceeds the
ahead torque. The formulas are applicable for solid propeller shafts only.
19.3.1 Design Criteria at 35°C (95°F)
The minimum required contact surface (grip) pressure, Pmin, at 35°C (95°F) and the corresponding
minimum pull-up length, δmin, are to be determined by the following equations:
⎡ 2⎤
ST ⎢ ⎛F ⎞ ⎥
Pmin = − Sτ + μ 2 + B⎜⎜ v ⎟⎟ N/mm2 (kgf/mm2, psi)
AB ⎢ ⎝T ⎠ ⎥
⎣ ⎦

Ds ⎡ 1 ⎛ K 2 +1 ⎞ 1 ⎤
δmin = Pmin ⎢ ⎜ + ν ⎟+ (1 − ν ) ⎥ mm (in.)
2τ ⎜ K 2 −1 b ⎟ E s
⎢⎣ E b ⎝ ⎠ s ⎥⎦

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 45
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

If the rated propeller thrust, T, is not known, it can be estimated as the thrust of a free running
vessel, using the following equations, whichever yields the greater value of pmin:

c1 H c 2 × 10 6 H
T= or T= N (kgf, lbf)
V PR

19.3.2 Design Criteria at 0°C (32°F)

The maximum permissible contact surface (grip) pressure, Pmax, at 0°C (32°F), and the corresponding
maximum permissible pull-up length, δmax, are to be determined from the following equations:

σ E ( K 2 − 1)
Pmax = N/mm2 (kgf/mm2, psi)
3K 4 + 1
Pmax
δmax = δmin mm (in.)
Pmin

19.3.3 Design Criteria at Fitting Temperature

The pull-up length, δt, at temperature t, where t < 35°C (95°F), and the corresponding contact
surface (grip) pressure, Pt, are to be determined by the following equations:
Ds
δt = δmin + (αb – αs)(tref – t) mm (in.)
2τ
δt
Pt = Pmin N/mm2 (kgf/mm2, psi)
δ min
The minimum push-up load, Wt, at temperature t is to be as follows:

Wt = APt (μ + τ) N (kgf, lbf)

The variables and constants used in 4-3-2/19.3.1, 4-3-2/19.3.2 and 4-3-2/19.3.3 are defined as
follows:
c = coefficient, dependent on the type of propulsion drive
= 1.0 for turbines, geared diesel drives, electric drives and direct diesel
with a hydraulic, electromagnetic or high elasticity coupling.
= 1.2 for a direct diesel drive.
Higher values may be necessary for cases where extremely high pulsating
torque is expected in service.
c1 = constant = 1760 (132, 295)
c2 = constant = 57.3 (4.3, 0.38)
t = fitting temperature; °C (°F); t < tref

tref = 35°C (95°F)

A = 100% theoretical contact surface area between propeller boss and shaft,
disregarding oil grooves (i.e., A = πDsL); mm2 (in2). Typically, the propeller
boss forward and aft counterbore lengths (l1 and l2 in 4-3-2/Figure 3) and
the forward and aft inner edge radii (r1 and r2 in 4-3-2/Figure 3), if any, are
to be excluded.
B = μ2 − S2τ2

46 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

Db = mean outer diameter of propeller boss, mm (in.). Db is to be calculated as the

mean of
Dba + Dbm + Dbf
Dbm, Dbf and Dba (i.e., Db = ),
3
which are the outer diameters of boss corresponding to Ds, the forward point
of contact and the aft point of contact, respectively (see 4-3-2/Figure 3).
Ds = diameter of tail shaft at mid-point of the taper in axial direction, mm (in.),
taking into account the exclusion of forward and aft counterbore length and
the forward and aft edge radii (see 4-3-2/Figure 3).
Eb = modulus of elasticity for boss material, N/mm2 (kgf/mm2, psi). Material
properties are given below.
Es = modulus of elasticity of shaft material, N/mm2 (kgf/mm2, psi). Material
properties are given below.
2cQ
Fv = shear force at propeller/shaft interface = , N (kgf, lbf)
Ds
H = rated power, kW (PS, hp)
Db
K =
Ds
L = contact length, mm (in.), see 4-3-2/Figure 3.
P = mean propeller pitch, mm (in.)
Q = rated torque corresponding to the rated power, H, and the propeller speed, R,
N-mm (kgf-mm, lbf-in)
H
= 9550 × 10 3 N-mm
R
H
= 716,200 kgf-mm
R
H
= 63,025 lbf-in
R
R = propeller speed at rated power, rpm
S = factor of safety against slip at 35°C (95°F). S is to be at least 2.8 under the
section of rated torque (based on maximum continuous rating) plus torque
due to torsional vibrations.
T = rated propeller thrust, N (kgf, lbf)
V = vessel speed at rated power, knots
αb = coefficient of linear expansion of shaft material, mm/mm-°C (in/in-°F).
Material properties are given below.
αs = coefficient of linear expansion of shaft material, mm/mm-°C (in/in-°F).
Material properties are given below.
μ = coefficient of friction between contact surfaces. For oil injection method of
fit, μ is to be taken as no greater than 0.13 for bronze/steel propeller bosses
on steel shafts. For dry method of fit using cast iron on steel shafts, μ is to be
taken as no greater than 0.18.
vb = Poisson’s ratio for boss material. Material properties are given below.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

vs = Poisson’s ratio for shaft material. Material properties are given below.

τ = taper of tail shaft on radius (e.g., if taper = 1/15 on diameter, τ = 1/30 on

radius). τ is not to exceed 1/30.
σE = maximum equivalent uniaxial stress in the boss at 0°F (32°F) based on the
von Mises-Hencky criterion, N/mm2 (kgf/mm2, psi). For the purposes of
these calculations, σE is to be taken as 70% of the minimum specified yield
strength of the material as defined in 2-3-1/13.3. For cast iron, σE is to be
taken as 30% of the minimum specified tensile strength.
The following material constants may be used:
Modulus of Elasticity, E Poisson’s Coefficient of Expansion, α
2 2
Material N/mm kgf/mm psi Ratio, v mm/mm°C in./in.°F
Cast and forged steel 20.6 × 104 2.1 × 104 29.8 × 106 0.29 12.0 × 10−6 6.67 × 10−6
Cast iron 9.8 × 104 1.0 × 104 14.2 × 106 0.26 12.0 × 10−6 6.67 × 10−6
Bronzes, Types 2 & 3 10.8 × 104 1.1 × 104 15.6 × 106 0.33 17.5 × 10−6 9.72 × 10−6
−6
Bronzes, Types 4 & 5 11.8 × 10 4
1.2 × 10 4
17.1 × 10 6
0.33 17.5 × 10 9.72 × 10−6

FIGURE 3
Keyless Propeller – Theoretical Contact Surface Area
Between Propeller Boss and Shaft (1998)
(Refer to 4-3-1/15.3 and 4-3-2/19.3)

l2

r2
l1
r1

Dba Dbm Dbf

Ds

// //
L

21 Protection Against Corrosion

21.1 Propeller Aft End

The exposed steel of the shaft is to be protected from the action of the water by filling all spaces between
cap, hub and shaft with a suitable material. The propeller is to be fitted with a fairwater cap, acorn nut, or
other suitable after end sealing arrangement which prevents sea water from having contact with the shaft
taper area. See 4-3-2/Figure 4 for a typical sealing arrangement.

48 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 2 Propellers 4-3-2

21.3 Propeller Forward End

The propeller assembly is to be sealed at the forward end with a well-fitted, soft-rubber packing ring.
When the rubber ring is fitted in an external gland, the hub counterbore is to be filled with suitable
material, and clearances between shaft liner and hub counterbore are to be kept to a minimum. When the
rubber ring is fitted internally, ample clearance is to be provided between liner and hub and the ring is to
be sufficiently oversize to squeeze into the clearance space when the propeller is driven up on the shaft;
and, where necessary, a filler piece is to be fitted in the propeller hub keyway to provide a flat, unbroken
seating for the ring.
The recess formed at the small end of the taper by the overhanging propeller hub is to be packed with a
rust preventive compound before the propeller nut is put on.

21.5 Noncorrosive, Non-pitting Alloys

The sealing arrangements above are not required where the tail shaft is fabricated of corrosion-resistant,
pitting-resistant alloy unless required by the manufacturer.

FIGURE 4
Propeller Hub Details

3 Rake

12 7
1 2 11
8
Keyway detail

9
0.125D

5 7

4
8 8

10 7
6
Typical hub seals
4

Section of typical built-up propeller

1 Liberal Fillet 7 Soft rubber ring

2 Chamfer corners of key 8 Fill and vent holes. One to
3 Break sharp corners of keyway in shaft be centered on keyway
4 Fill with suitable sealing 9 See 4-3-2/9.7
material 10 See typical hub seals
5 Locking device 11 Face (tension side)
6 Threaded holes for jack bolts 12 Back (compression side)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 49
PART Section 3: Steering Gear

4
CHAPTER 3 Propulsion and Maneuvering Machinery

SECTION 3 Steering Gear

1 General

1.1 Application
These requirements apply to vessels which have rule-required upper rudder stock diameter less than 230 mm
(9 in.). Where the rule-required upper rudder stock diameter is 230 mm (9 in.) or above, the Steel Vessel
Rules are to be applied.
Where a rudder is not fitted and steering is achieved by change of setting of the propulsion units, such as
the use of cycloidal, azimuthing or similar type propulsion systems, Section 4-3-5 in Part 4 of the Steel
Vessel Rules is to be applied.

1.3 Definitions
1.3.1 Main Steering Gear
Main steering gear is the machinery, rudder actuators, power units, ancillary equipment and the
means of applying torque to the rudder stock (e.g., tiller or quadrant) necessary for effecting
movement of the rudder for the purpose of steering the vessel.
1.3.2 Auxiliary Steering Gear
Auxiliary steering gear is the equipment other than any part of the main steering gear necessary to
steer the vessel in the event of failure of the main steering gear, but not including the tiller,
quadrant or components serving the same purpose.
1.3.3 Control System
Control system is the equipment by which orders are transmitted from the navigation bridge to the
power units. Control systems comprise transmitters, receivers, hydraulic control pumps and their
associated motors, motor controllers, piping and cables. For the purpose of the Rules, steering
wheels or steering levers are not considered to be part of the control system.
1.3.4 Power Units
A steering gear power unit is:
i) In the case of electric steering gears, an electric motor and its associated electrical
equipment,
ii) In the case of electro-hydraulic steering gears, an electric motor and its associated
electrical equipment and connected pump(s), and
iii) In the case of other hydraulic steering gears, a driving engine and connected pump(s).
1.3.5 Power Actuating System
Power actuating system is the hydraulic equipment provided for supplying power to turn the
rudder stock, comprising a power unit or units together with the associated pipes and fittings and a
rudder actuator. The power actuating systems may share common mechanical components (i.e.,
tiller, quadrant, rudder stock, or components serving the same purpose).

50 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

1.3.6 Rudder Actuator

Rudder actuator is the component which directly converts hydraulic pressure into mechanical
action to move the rudder.
1.3.7 Maximum Working Pressure
Maximum working pressure is the expected pressure in the system when the steering gear is
operated to comply with 4-3-3/1.9.

1.5 Plans and Data

Plans and data of the steering gear system to be submitted are as follows:
1.5.1 Plans
General arrangements of the main and auxiliary steering gears, and of the steering gear compartment.
Assembly of upper rudder stock, tiller, tie rod, rudder actuators, etc., as applicable.
Construction details of all torque-transmitting components of steering gear, such as tiller, tiller pin,
tiller/rudder stock interference fit mechanism, tie rod, rudder actuator, etc, including bill of materials,
welding procedures, nondestructive testing, as applicable.
Schematic hydraulic piping diagram, incorporating hydraulic logic diagram, and including bill of
materials, typical pipe to pipe joint details, pipe to valve joint details, pipe to equipment joint details,
pressure rating of valves and pipe fittings and pressure relief valve settings.
Steering gear control system incorporating schematic electrical control logic diagram, instrumentation,
alarm devices, etc, and including bill of materials.
Electrical power supply to power units and to steering gear control, including schematic diagram
of motor controllers, feeder cables, feeder cable electrical protection.
1.5.2 Data
Rated torque of main steering gear.
Calculations of torque-transmitting components such as tiller, tie rod, rudder actuator, etc.

1.7 Power Operation

The main steering gear is to be power-operated by one or more power units if the rule-required upper rudder
stock diameter is 120 mm (4.7 in.) or greater.
Notwithstanding the above, the performance requirements stated in 4-3-3/1.9 and 4-3-3/1.11 are to be used
to determine if it is necessary for the main and auxiliary steering gears to be power-operated.

1.9 Main Steering Gear

The main steering gear is to be capable of putting the rudder from 35° on one side to 35° on the other side
with the vessel running ahead at maximum continuous shaft rpm and at the summer load waterline; and
under the same conditions, the travel time from 35° on either side to 30° on the other side is not to be more
than 28 seconds. For controllable pitch propellers, the propeller pitch is to be at the maximum design pitch
approved for the above maximum continuous ahead rated rpm.

1.11 Auxiliary Steering Gear

The auxiliary steering gear is to be capable of putting the rudder from 15° on one side to 15° on the other
side in not more than 60 seconds with the vessel running ahead at half speed, or seven knots, whichever is
greater.
The auxiliary steering gear is to be so arranged that the failure of the main steering gear will not render it
inoperative. Likewise, failure of the auxiliary steering gear is not to affect the main steering gear.
An auxiliary steering gear is not required under the following conditions.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

1.11.1
When the main steering gear comprises two or more power units, and is so arranged that after a
single failure in its piping system or in one of the power units, the defect can be isolated so that
the steering capability can be maintained or regained; and provided that
1.11.1(a) For passenger vessel, the main steering gear is capable of operating the rudder, as
required in 4-3-3/1.9, while any one of the power units is out of operation; and
1.11.1(b) For cargo vessel, the main steering gear is to be capable of operating the rudder, as
required by 4-3-3/1.9, while all the power units are in operation.
1.11.2
When the main steering gear is non-power-operated such as an orbitrol system, or consists solely
of mechanical components such as sheaves, blocks, wires, chains, etc.

1.13 Steering Gear Compartment Unit Location

The main and the auxiliary steering gears are to be protected from weather. The power units may be
located either within or outside of the compartment containing the rudder actuators. In the event of loss of
hydraulic fluid and of the need to restore the operation of the main or the auxiliary steering gear, the steering
gear compartment is to be provided with handrails and gratings or other non-slip surfaces to ensure suitable
working conditions.
In the event of control system failure, or the need to operate the main or the auxiliary steering gear from
within the steering compartment or from positions other than the navigation bridge, vessels of 500 gross
tons and above are to be provided with a means to indicate the position of the rudder at these positions
where emergency steering is to be conducted.

3 Materials

3.1 General
All steering gear components transmitting a force to the rudder and pressure retaining components of the
hydraulic rudder actuator are to be of steel or other approved ductile material. The use of gray cast iron or
other material having an elongation less than 12% in 50 mm (2 in.) is not acceptable.

3.3 Material Testing (2010)

Except as modified below, materials for the parts and components mentioned in 4-3-3/3.1 are to be tested
in the presence of the Surveyor in accordance with the requirements of Chapter 3 of the ABS Rules for
Materials and Welding (Part 2).
Material tests for steering gear coupling bolts and torque transmitting keys need not be witnessed by the
Surveyor.
Material tests for commercially supplied tie-rod nuts need not be witnessed by the Surveyor, provided the
nuts are in compliance with the approved steering gear drawings and are appropriately marked and
identified in accordance with a recognized industry standard. Mill test reports for the tie-rod nuts are to be
made available to the Surveyor upon request. For all non-standard tie-rod nuts, material testing is required
to be performed in the presence of the Surveyor.
Material tests for forged, welded or seamless steel parts (including the internal components) and all non-
ferrous parts of rudder actuators that are under 150 mm (6 in.) in internal diameter need not be carried out
in the presence of the Surveyor. Such parts are to comply with the requirements of Chapter 3 of the above
referenced Part 2, or such other appropriate material specifications as may be approved in connection with
a particular design, and will be accepted on the basis of presentation of mill certificates to the Surveyor for
verification.

52 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

5 Design

5.1 Power Gear Stops (2010)

Power-operated steering gears are to be provided with arrangements, such as limit switches, for stopping
the steering gear before the structural rudder stops (see 3-2-11/1.7) or positive mechanical stops within the
steering gear are reached. These arrangements are to be synchronized with the rudder stock or position of
the steering gear itself rather than with the steering-gear control system.

5.3 Mechanical Components

All steering gear parts transmitting force to or from the rudder, such as tillers, quadrants, rams, pins, tie
rods and keys, are to be proportioned to have strength equivalent to that of the rule-required upper rudder
stock diameter.

5.4 Steering Gear Torque (2003)

5.4.1 Minimum Required Rated Torque
The rated torque of the steering gear is not to be less than the expected torque, as defined in
3-2-11/1.5.
5.4.2 Maximum Allowable Torque
The transmitted torque, Tmax, of the steering gear is not to be greater than the maximum allowable
torque, Tar, based on the actual rudder stock diameter.
5.4.2(a) Transmitted torque. The transmitted torque, Tmax, is to be based on the relief valve
setting and to be determined in accordance with the following equations:
For ram type actuator:
Tmax = P·N·A·L2/(C·cos2θ) kN-m (tf-m, Ltf-ft)
For rotary vane type actuator:
Tmax = P·N·A·L2/C kN-m (tf-m, Ltf-ft)
For linked cylinder type actuator:
Tmax = P·N·A·L2 cos θ/C kN-m (tf-m, Ltf-ft)
where
P = steering gear relief valve setting pressure, bar (kgf/cm2, psi)
N = number of active pistons or vanes
A = area of piston or vane, mm2 (cm2, in2)
L2 = torque arm, equal the distance from the point of application of the force on
the arm to the center of the rudder stock at 0 deg of the rudder angle, m (ft)
C = factor, 10000 (1000, 2240)
θ = maximum permissible rudder angle (normally 35 degrees)
5.4.2(b) Maximum allowable torque for rudder stock. The maximum allowable torque “Tar” for
the actual rudder stock diameter is to be determined in accordance with the following equation:
Tar = 2.0(Dr/Nu)3/Ks kN-m (tf-m, Ltf-ft)
where
Ks = material factor for rudder stock (see 3-2-11/1.3)
Dr = actual rudder stock diameter at minimum point below the tiller or the rotor,
mm (in.)
Nu = factor, 42.0 (89.9, 2.39)

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

5.5 Tiller
Tillers are to comply with the following requirements. All terms in the formulae are to have consistent
units.
5.5.1
Depth of the tiller hub is not to be less than the rule-required upper rudder stock diameter.
5.5.2
Thickness of the tiller hub is not to be less than one third of the rule-required upper rudder stock
diameter.
5.5.3
Notwithstanding 4-3-3/5.5.2 above, the polar section modulus of the tiller hub is not to be less than:
Kh
0.196S 3
Ks
where
S = rule-required upper rudder stock diameter.
Ks = material factor of the rudder stock (see 3-2-11/1.3)
Kh = material factor of the hub (see 3-2-11/1.3)

5.5.4
The shear area of the tiller key is not to be less than:
0.196 S 3 K k
⋅
r Ks
where
r = mean radius of the rudder stock in way of the key
Kk = material factor of the key (see 3-2-11/1.3)
Other symbols are defined above.
5.5.5
Bearing stress of the tiller and rudder stock keyways are not to be more than 0.9 times the material
yield stress.
5.5.6
If the tiller is shrink-fitted to the rudder stock, preloading and stress calculations and fitting instructions
are to be submitted. The calculated torsional holding capacity is to be at least two times the
transmitted torque based on the steering gear relief valve setting. Preload stress is not to exceed
70% of the minimum yield strength.
5.5.7
Section modulus of the tiller arm at any point within its length is not to be less than:

0.167 S 3 (L2 − L1 ) K t
⋅
L2 Ks
where
L2 = distance from the point of application of the force on the tiller to the center
of rudder stock

54 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

L1 = distance between the section of the tiller arm under consideration and the
center of the rudder stock
Kt = material factor of the tiller or quadrant arm (see 3-2-11/1.3)
Other symbols are defined above.
5.5.8 (2009)
Split or semi-circular tiller or quadrant hubs assembled by bolting are to have bolts on each side
having a total cross-sectional area not less than that given below (use a consistent system of units):
0.196 S 3 K b
⋅
L3 Ks
where
L3 = distance between the center of the bolts and the center of the rudder stock
Kb = material factor of bolt (see 3-2-11/1.3)
Other symbols are as defined above.
The thickness of the bolting flange is not to be less than the minimum required diameter of the bolt.
5.5.9
Where the tiller is of welded construction, weld design and weld sizes are to be proportioned such
that they are commensurate with the strength of the tiller.

5.7 Pin
Shear area of the tiller pin is not to be less than:
0.196 S 3 K p
⋅
L2 Ks
where
Kp = material factor of the pin (see 3-2-11/1.3)
Other symbols are defined above.

5.9 Tie Rod (Jockey Bar)

The buckling strength of the tie rod is not to be less than:

0.113S 3U R
L2
where
UR = ultimate tensile strength of the rudder stock
Other symbols are defined above.

5.11 Rudder Actuators

5.11.1 General
Rudder actuators are to meet the requirements in 4-3-3/3 for materials and material tests and 2-4-2/1
for welding. They are also to meet the requirements for pressure vessels in the Steel Vessel Rules,
specifically 4-4-1A1/3.1 (for malleable cast iron, use y = 0.5), 4-4-1A1/5 and 4-4-1A1/7 (in association
with S, as defined below) for design and 4-4-1A1/21 for hydrostatic tests. The maximum allowable
stress, S, is not to exceed the lower of the following:

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

U Y
or
A B
where
U = minimum specified tensile strength of material at room temperature
Y = minimum specified yield point or yield strength
A, B = factors as given in the following table.
Factor Rolled or Forged Cast Steel Nodular
Steel Cast Iron
A 3.5 4 5
B 1.7 2 3
5.11.2 Oil Seals
Oil seals between non-moving parts forming the external boundary are to be of the pressure seal
type. Oil seals between moving parts forming the external pressure boundary are to be fitted in
duplicate so that the failure of one seal does not render the actuator inoperative. Alternative seal
arrangement may be acceptable, provided equivalent protection against leakage can be ensured.

5.13 Mechanical Steering Gear

Where mechanical steering systems are permitted, the following are applicable.
5.13.1 Steering Chains and Wire Ropes
Steering chains and wire rope are to be tested as required by Sections 2-2-1 and 2-2-2 of the ABS
Rules for Materials and Welding (Part 2), respectively.
5.13.2 Sheaves
Sheaves are to be of ample size and so placed as to provide a fair lead to the quadrant and avoid
acute angles. Parts subjected to shock are not to be of cast iron. Guards are to be placed around the
sheaves to protect against injury. For sheaves intended for use with ropes, the radius of the grooves
is to be equal to that of the rope plus 0.8 mm (1/32 in.), and the sheave diameter is to be determined
on the basis of wire rope flexibility. For 6 × 37 wire rope, the sheave diameter is to be not less
than 18 times that of the rope. For wire ropes of lesser flexibility, the sheave diameter is to be
increased accordingly. Sheave diameters for chain are to be not less than 30 times the chain diameter.
5.13.3 Buffers
Steering gears other than the hydraulic type are to be designed with suitable buffer arrangement to
relieve the gear from shocks to the rudder.

7 Hydraulic System

7.1 Pipes, Valves and Fittings

Pipes, valves and fittings are to meet the requirements of 4-4-6/1, as applicable. The design pressure of piping
components subject to internal hydraulic pressure is to be at least 1.25 times the maximum working pressure
of the system. Arrangements for bleeding air from the hydraulic system are to be provided, where necessary.

7.3 Relief Valves (2010)

Relief valves are to be provided for the protection of the hydraulic system at any part which can be isolated
and in which pressure can be generated from the power source or from external forces. Each relief valve is
to be capable of relieving not less than 110% of the full flow of the pump(s) which can discharge through
it. With this flow condition, the maximum pressure rise is not to exceed 10% of the relief valve setting,
taking into consideration increase in oil viscosity for extreme ambient conditions.
The relief valve setting is to be at least 1.25 times the maximum working pressure (see 4-3-3/1.3.7), but is
not to exceed the maximum design pressure (see 4-3-3/7.1).

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

7.5 Filtration
A means is to be provided to maintain cleanliness of the hydraulic fluid.

7.7 Single Failure

Where multiple power units are provided and an auxiliary steering gear is not fitted, the steering gear
hydraulic system is to be designed so that after a single failure in its piping system, one of the power units,
or mechanical connection to the power units, the defect can be isolated so that the integrity of the
remaining part of the system will not be impaired and the steering capability can be maintained or
regained. For this purpose, the piping system associated with each power unit is to be independent of that
of the other units as far as practicable and connections are to be made only where necessary. Isolation
valves are to be fitted, as necessary, to allow any single failure in the piping system to be isolated and the
steering gear to be operated with the remaining intact part of the system. Isolation valves are to be fitted at
the pipe connections to rudder actuators. Where a non-duplicated rudder actuator is employed, the isolation
valves are to be mounted directly on the actuator. Piping systems are to be so arranged that transfer
between power units can be readily affected.

7.9 Reservoir and Storage Tank

All open-loop hydraulic systems are to be provided with an oil reservoir of suitable capacity. In addition,
for vessels of 500 gross tons and above, a fixed storage tank having sufficient capacity to recharge at least
one hydraulic power system including the reservoir is to be provided. The tank is to be permanently
connected by piping in such a manner that the system can be readily recharged from a position within the
steering gear compartment.

9 Power Units
If the rule required upper rudder stock diameter is 120 mm (4.7 in.) or greater, power units are to be tested
and certified in accordance with the following requirements. If the rule-required upper rudder stock
diameter is less than 120 mm (4.7 in.), and if the vessel is 500 gross tons or greater, power units are to be
tested and certified in accordance with 4-3-3/9.3 only. For vessels less than 500 gross tons, power units
may be accepted based on manufacturer’s guarantee for suitability for the intended purpose and subject to
satisfactory functional tests after installation.

9.1 Prototype Test

A prototype of each new design power unit pump is to be shop-tested for a duration of not less than 100
hours. The testing is to be carried out in accordance with an approved agenda and is to include the following
as a minimum.
9.1.1
The pump and stroke control (or directional control valve) is to be operated continuously from full
flow and relief valve pressure in one direction through idle to full flow and relief valve pressure in
the opposite direction.
9.1.2
Pump suction conditions are to simulate lowest anticipated suction head. The power unit is to be
checked for abnormal heating, excessive vibration or other irregularities. Following the test, the
power unit pump is to be disassembled and inspected in the presence of a Surveyor.

9.3 Production Unit Test

Each power unit pump is to meet the hydrostatic and capacity tests in accordance with 4-4-2/1, as applicable.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

11 Steering Gear Control System

11.1 Locations of Control

11.1.1 (1998)
The main steering gear is to be provided with control both from the navigation bridge and from
within the steering gear compartment. However, if the power unit is located in a space other than
the steering compartment, the control is to be provided in that space instead of the steering
compartment. For the purpose of controlling from the steering gear compartment (or the space
containing the power unit), a means is to be provided in the steering compartment (or the space
containing the power unit) to disconnect any control system from the navigation bridge. Such
means for disconnecting are to be operable by a single person without the need for tools.
11.1.2
The auxiliary steering gear is to be operable from a space in which the operation of the auxiliary
steering gear can be effectively carried out, or from within the steering compartment. However, if
power operated, it is to be provided with control from the navigation bridge also.
11.1.3
Where duplicate (or more) power units are provided and an auxiliary steering gear is not fitted,
two independent systems of control are to be provided. Each of these systems is to meet the
requirements of the control system of the main steering gear (See 4-3-3/11.1.1). Where the control
system consists of a hydraulic telemotor, a second independent system need not be fitted.
11.1.4
If the steering gear is operated by manual means only, such as by means of a steering wheel through
a mechanical or a non-power-operated hydraulic system, only the requirements of 4-3-3/11.7 and
4-3-3/11.9.1 are applicable.

11.3 Control System Segregation

11.3.1
Control systems of the main and the auxiliary steering gears are to be independent of each other in
all respects. The control wires are to be separated as far as practicable throughout their length.
Where found necessary, the wiring of the two systems may share the same terminal box, provided
a safety barrier is fitted in the box to segregate the wiring.
11.3.2
If the main steering gear consists of duplicated (or more) power units and an auxiliary steering is
not fitted, the two independent means of control are to comply with the segregation requirement of
4-3-3/11.3.1. However, this does not require duplication of the steering lever or other steering
apparatus on the navigation bridge.
11.3.3
If the main steering gear consists of a single power unit and the auxiliary steering gear is not
power operated, only one control system for the main steering gear need be provided.

11.5 Control System Power Supply

Electrical power for the steering gear control system is to be derived from the motor controller of the power
unit that it is controlling, or from the main switchboard at a point adjacent to the supply to the power unit.

11.7 Communication
A means of communication is to be provided between the navigation bridge and all other locations where
steering can be effected, such as the steering gear compartment, the space where the power units are
located and the space where auxiliary steering gear is to be operated, as applicable.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

11.9 Instrumentation and Alarms

The following instruments and alarms are to be provided. The audible and visual alarms are to have provisions
for testing.
11.9.1 Rudder Position Indicator
The angular position of the rudder is to be indicated on the navigational bridge and all other locations
where steering can be effected, such as the steering gear compartment, the space where the power
units are located and the space where auxiliary steering gear is to be operated, as applicable. The
rudder angle indication is to be independent of the steering gear control system.
11.9.2 Autopilot
Where autopilot is fitted, a visual and audible alarm is to be provided on the navigation bridge to
indicate its failure.
Where a power unit is provided and steering is controlled from navigation bridge, the following are applicable:
11.9.3 Motor Alarm
A visual and audible alarm is to be given on the navigation bridge and the engine room control
station to indicate an overload condition of the steering gear power unit motor. Where three phase
electrical power is used, a visual audible alarm is to be installed which indicates failure of any one
of the supply phases. The operation of these alarms is not to interrupt the circuit.
11.9.4 Motor Running Indicators
Indicators for running indication of motors are to be installed on the navigation bridge and the
engine room control station.
11.9.5 Power Failure
A visual and audible alarm is to be given on the navigation bridge and engine room control station
to indicate a power failure to any one of the steering gear power units.
11.9.6 Control Power Failure
A visual and audible alarm is to be given on the navigation bridge and the engine room control
station to indicate an electrical power failure in any steering gear control circuit or remote control
circuit.
In addition, hydraulic power operated steering gear is to be provided with the following:
11.9.7 Low Oil Level Alarm
A visual and audible alarm is to be given on the navigation bridge and engine room control station
to indicate a low oil level in any power unit reservoir.
11.9.8 Hydraulic Lock (2006)
Where the arrangement is such that a single failure may cause hydraulic lock and loss of steering,
an audible and visual hydraulic lock alarm which identifies the failed system or component is to
be provided on the navigation bridge. The alarm is to be activated upon steering gear failure if:
• Position of the variable displacement pump control system does not correspond to the given
order, or
• Incorrect position of the 3-way full flow valve or similar in the constant delivery pump system
is detected.
Alternatively, an independent steering failure alarm for follow-up control systems complying with
the following requirements may be provided in lieu of a hydraulic lock alarm.
Where an independent steering failure alarm is installed for follow-up control systems it is to
comply with the following:

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

11.9.8(a) The steering failure alarm system is to actuate an audible and visible alarm in the
wheelhouse when the actual position of the rudder differs by more than 5 degrees from the rudder
position ordered by the follow-up control systems for more than:
• 30 seconds for ordered rudder position changes of 70 degrees;
• 6.5 seconds for ordered rudder position changes of 5 degrees; and
The time period calculated by the following formula for ordered rudder positions changes between
5 degrees and 70 degrees:
t = (R/2.76) + 4.64
where:
t = maximum time delay in seconds
R = ordered rudder change in degrees
11.9.8(b) The steering failure alarm system must be separate from, and independent of, each
steering gear control system, except for input received from the steering wheel shaft.
11.9.8(c) Each steering failure alarm system is to be supplied by a circuit that:
i) Is independent of other steering gear system and steering alarm circuits.
ii) Is fed from the emergency power source through the emergency distribution panel in the
wheelhouse, if installed; and
iii) Has no overcurrent protection except short circuit protection
11.9.9 Autopilot Override (2003)
11.9.9(a) Steering gear systems provided with an autopilot system are to have a device at the
primary steering station to completely disconnect the autopilot control to permit change over to
manual operation of the steering gear control system. A display is to be provided at the steering
station to ensure that the helmsman can readily and clearly recognize which mode of steering
control (autopilot or manual) is in operation.
11.9.9(b) In addition to the change over device as in 4-3-3/11.9.9(a), for primary steering stations,
where fitted with an automatic autopilot override to change over from autopilot control to manual
operation, the following are to be provided.
i) The automatic override of the autopilot is to occur when the manual helm order is 5 degrees
of rudder angle or greater.
ii) An audible and visual alarm is to be provided at the primary steering station in the event
that the automatic autopilot override fails to respond when the manual helm order is 5
degrees of rudder angle or greater. The alarm is to be separate and distinct from other
bridge alarms and is to continue to sound until it is acknowledged.
iii) An audible and visual alarm that is immediately activated upon automatic autopilot override
actuation is to be provided at the primary steering station. The alarm is to be distinct from
other bridge alarms and is to continue to sound until it is acknowledged.

11.11 Operating Instructions (1999)

Appropriate operating instructions with a block diagram showing the change-over procedures for steering
control systems and steering gear power units are to be permanently posted at a conspicuous location on
the navigation bridge and in or near the steering gear compartment. Where system failure alarms in 4-3-3/11.9.8
are provided, appropriate instructions are to be permanently posted on the navigation bridge to shut down
the failed system.

13 Electrical Power Supply

Electrical power circuits are to meet the requirements of 4-6-2/11 and 4-6-2/5.3.5.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 3 Steering Gear 4-3-3

15 Testing and Trials

15.1 Testing of Piping System

The following tests are to be performed in the presence of the Surveyor.
15.1.1 Shop Tests (2008)
After fabrication, each component of the steering gear piping system, including the power units,
hydraulic cylinders and piping, is to be hydrostatically tested at the plant of manufacture to 1.5
times the relief valve setting.
15.1.2 Installation Tests
After installation in the vessel, the complete piping system, including power units, hydraulic cylinders
and piping, is to be subjected to a hydrostatic test equal to 1.1 times the relief valve setting, including
a check of the relief valve operation.

15.3 Trials
The steering gear is to be tried out on the trial trip in order to demonstrate to the Surveyor’s satisfaction
that the requirements of the Rules have been met. The trial is to include the operation of the following:
15.3.1
The main steering gear, including demonstration of the performance requirements of 4-3-3/1.9 or
with the rudder fully submerged. Where full rudder submergence cannot be obtained in ballast
conditions, special consideration may be given to specified trials with less than full rudder
submergence. Trials are to be carried out with the vessel running ahead at maximum continuous
rated shaft RPM. For controllable pitch propellers, the propeller pitch is to be at the maximum
design pitch approved for the above maximum continuous ahead RPM.
15.3.2
The auxiliary steering gear, if required, including demonstration to the performance requirements
of 4-3-3/1.11 and transfer between main and auxiliary steering gear.
15.3.3
The power units, including transfer between power units.
15.3.4
The emergency power supply required by 4-6-2/5.3.5.
15.3.5
The steering gear controls, including transfer of control and local control.
15.3.6
The means of communications, as required by 4-3-3/11.7.
15.3.7
The alarms and indicators required by 4-3-3/11.9 (test may be done at dockside).
15.3.8
The storage and recharging system contained in 4-3-3/7.9 (test may be done at dockside).
15.3.9
The isolating of one power actuating system and checking for regaining steering capability are
required by 4-3-3/7.7, if applicable (test may be done at dockside).
15.3.10
Where the steering gear is designed to avoid hydraulic locking, this feature is to be demonstrated.

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PART Section 4: Waterjets

4
CHAPTER 3 Propulsion and Maneuvering Machinery

SECTION 4 Waterjets

1 Waterjets

1.1 General
Full details are to be submitted for the force transmitting parts of waterjet units, including material
specifications. For vessels over 24 m (79 ft), the units are to be manufactured under Surveys. Mill certificates
are to be provided for the components of the steering section. The material tests for the impellers, shafts
and couplings are to be witnessed by the Surveyor. Hydraulic cylinders are to be manufactured and inspected
in accordance with the requirements of 4-4-6/3. The use of galvanically dissimilar metallic materials is to
be considered in the waterjet design.

1.3 Design
Design basis stress calculations for the impellers, shafting, steering mechanism and reversing mechanism
are to be submitted to substantiate the suitability and strength of component parts for the intended service.
For the purpose of design review, the stress calculations are to cover the “worst case” condition for each
component. The factor of safety for the above components is not to be less than 2.0 when determined by
the following equation:
1 S S
= s + a
FS U E
nor less than 4.0 when determined by the following equation:
U
FS =
Ss
where
FS = factor of safety
Ss = steady stress of low cycle alternating stress
Sa = alternating stress
U = ultimate tensile strength of material
E = corrected fatigue strength of material (based on 108 cycles)

1.5 Housings
Calculations or test results to substantiate the suitability and strength of the pressure and suction housing
are to be submitted for review. The condition with the inlet of the suction blocked is also to be considered.
A factor of safety of not less than four based on the ultimate tensile strength of the material (or two based
on the yield strength) is to be maintained at each point in the housing. Housing are to be hydrostatically
tested to 1.5 times the maximum working pressure or to 3.4 bar (3.5 kgf/cm2, 50 psi), whichever is greater.

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Chapter 3 Propulsion and Maneuvering Machinery
Section 4 Waterjets 4-3-4

1.7 Reversing Mechanisms

Astern thrust is to be provided in sufficient amounts to secure proper control of the vessel in all normal
circumstances. The reversing mechanism is to provide for reversing at full power.

1.9 Impeller Bearings

Antifriction bearings are to have a B10 life of at least 80,000 hours.

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PART Section 5: Propulsion Redundancy

4
CHAPTER 3 Propulsion and Maneuvering
Machinery

SECTION 5 Propulsion Redundancy (2005)

1 General

1.1 Application
The requirements in this Section apply to vessels equipped with propulsion and steering systems designed
to provide enhanced reliability and availability through functional redundancy. Application of the requirements
of this Section is optional. When a vessel is designed, built and surveyed in accordance with this Section,
and when found satisfactory, a classification notation, as specified in 4-3-5/3, as appropriate, will be granted.
It is a prerequisite that the vessels are also to be classed to either À ACCU or À ABCU notation, in
accordance with Part 4, Chapter 7.

1.3 Objective
The objective of this Section is to provide requirements which reduce the risk to personnel, the vessel,
other vessels or structures, the environment and the economic consequences due to a single failure causing
loss of propulsion or steering capability. This is achieved through varying degrees of redundancy based
upon the vessel’s Classification Notations, as described in 4-3-5/3.
The requirements in this Section aim to ensure that following a single failure, the vessel is capable of either:
i) Maintaining course and maneuverability at reduced speeds without intervention by other vessels, or
ii) Maintaining position under adverse weather conditions, as described in 4-3-5/7.1, to avoid uncontrolled
drift and navigating back to safe harbor when weather conditions are suitable.
In addition, this Section addresses aspects which would reduce the detrimental effects to the propulsion
systems due to a localized fire in the machinery spaces.

1.5 Definitions
For the purpose of this Section, the following definitions are applicable:
1.5.1 Auxiliary Services System
All support systems (e.g., fuel oil system, lubricating oil system, cooling water system, compressed
air and hydraulic systems, etc.) which are required to run propulsion machinery and propulsors.
1.5.2 Propulsion Machinery Space
Any space containing machinery or equipment forming part of the propulsion systems.
1.5.3 Propulsion Machine
A device (e.g., diesel engine, turbine, electrical motor, etc.) which develops mechanical energy to
drive a propulsor.
1.5.4 Propulsion System
A system designed to provide thrust to a vessel, consisting of one or more propulsion machines,
one or more propulsors, all necessary auxiliaries and associated control, alarm and safety systems.

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Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

1.5.5 Propulsor
A device (e.g., propeller, waterjet) which imparts force to a column of water in order to propel a
vessel, together with any equipment necessary to transmit the power from the propulsion machinery
to the device (e.g., shafting, gearing, etc.).
1.5.6 Steering System
A system designed to control the direction of movement of a vessel, including the rudder, steering
gear, etc.

1.7 Plans and Data to be Submitted

In addition to the plans and data required by the Rules, the following are to be submitted:
i) Results of computations showing that, upon any single failure in the propulsion and steering systems,
the vessel is able to meet the capability requirements of 4-3-5/7.1, if applicable, with details of the
computational methods used. Alternatively, the results of model testing are acceptable as evidence.
ii) A Failure Mode and Effect Analysis (FMEA) or equivalent. The integrity of the propulsion systems,
steering systems and auxiliary service systems is to be verified by means of a Failure Mode and
Effect Analysis (FMEA) or equivalent method and is to show that a single failure will not compromise
the criteria as specified in 4-3-5/7.
iii) A Testing Plan to cover the means whereby verification of the redundancy arrangements will be
accomplished.
iv) A general arrangement detailing locations of all machinery and equipment necessary for the correct
functioning of the propulsion and steering systems, including the routing of all associated power,
control and communication cables. (Required for R1-S and R2-S only).
v) Operating Manual, as required in 4-3-5/13.

3 Classification Notations
Where requested by the Owner, propulsion and steering installations which are found to comply with the
requirements specified in this Section and which have been constructed and installed under survey by the
Surveyor will be assigned with the following class notations, as appropriate.
i) R1 A vessel fitted with multiple propulsion machines but only a single propulsor and steering
system will be assigned the class notation R1.
ii) R2 A vessel fitted with multiple propulsion machines and also multiple propulsors and steering
systems (hence, multiple propulsion systems) will be assigned the class notation R2.
iii) R1-S A vessel fitted with only a single propulsor but having the propulsion machines arranged
in separate spaces such that a fire or flood in one space would not affect the propulsion machine(s)
in the other space(s) will be assigned the class notation R1-S.
iv) R2-S A vessel fitted with multiple propulsors (hence, multiple propulsion systems) which has
the propulsion machines and propulsors, and associated steering systems arranged in separate
spaces (propulsion machinery space and steering gear flat) such that a fire or flood in one space
would not affect the propulsion machine(s) and propulsor(s), and associated steering systems in
the other space(s) will be assigned the class notation R2-S.
Example arrangements for each of the above notations are shown in 4-3-5/Figure 1.
v) + (Plus Symbol) The mark + will be affixed to the end of any of the above class notations
(e.g., R1+, R2-S+) to denote that the vessel’s propulsion capability is such that, upon a single
failure, propulsive power can be maintained or immediately restored to the extent necessary to
withstand adverse weather conditions without drifting, in accordance with 4-3-5/7.3. The lack of
the mark + after the class notation indicates that the vessel is not intended to withstand the adverse
weather conditions in 4-3-5/7.3, but can maintain course and maneuverability at a reduced speed
under normal expected weather conditions, in accordance with 4-3-5/7.1.

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

FIGURE 1
Arrangements of Propulsion Redundancy
R1 R1-S

A-0 BHD

A-60/WT BHD
SG PM-1 SG PM-1
RG RG

PM-2 PM-2

R2 R2-S

SG1 RG 1 SG1 RG 1

PM-1 PM-1
A-0 BHD A-60/WT BHD
SG2 SG2

PM-2 PM-2
RG 2 RG 2

STEERING GEAR

REDUCTION PROPULSION
GEAR MACHINERY E-MOTOR

AZIMUTH THRUSTER

R2 (An Alternate Design Concept)

E-MOTOR

SG RG
PM

AZIMUTH THRUSTER

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Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

5 Single Failure Concept

The degree of redundancy required to meet the objectives of this Section is based upon a single failure
concept. The concept accepts that failures may occur but that only one such failure is likely at any time.
The final consequence of any single failure is not to compromise the propulsion and steering capability
required in 4-3-5/7, unless otherwise specified.

5.1 Single Failure Criteria

5.1.1 R1 Notation
For R1, the single failure criterion is applied to the propulsion machines, its auxiliary service
systems and its control systems. This notation does not consider failure of the propulsor or rudder,
or total loss of the propulsion machinery space or steering gear flat due to fire or flood.
5.1.2 R2 Notation
For R2, the single failure criterion is applied to the propulsion machines, propulsors, auxiliary
service systems, control systems and steering systems. This notation does not consider total loss
of the propulsion machinery space or steering gear flat due to fire or flood.
5.1.3 R1-S Notation
For R1-S, the single failure criterion is applied as for R1, but a fire or flood in one of the propulsion
machinery spaces is also considered.
5.1.4 R2-S Notation
For R2-S, the single failure criterion is applied as for R2, but a fire or flood in one of the propulsion
machinery spaces or steering gear flats is also considered.

7 Propulsion and Steering Capability

7.1 Vessels Without + in Class Notation

Upon a single failure, the propulsion system is to be continuously maintained or restored within two (2)
minutes (for alternate standby propulsion per 4-3-5/7.3 below) such that the vessel is capable of advancing
at a speed of at least one-half its design speed or seven knots, whichever is less, for at least 36 hours when
the vessel is fully loaded. Adequate steering capability is also to be maintained at this speed.

7.3 Vessels with + in Class Notation

In addition to 4-3-5/7.1 above, upon a single failure, the propulsion and steering system is to be continuously
maintained or immediately restored within two (2) minutes, as in the case when an alternate standby type
of propulsion is provided, (e.g., electric motor, diesel engine, waterjet propulsion, etc.) such that the vessel
is capable of maneuvering into an orientation of least resistance to the weather, and once in that
orientation, maintaining position such that the vessel will not drift for at least 36 hours. This may be
achieved by using all available propulsion and steering systems including thrusters, if provided. This is to
be possible in all weather conditions up to a wind speed of 17 m/s (33 knots) and significant wave height
of 4.5 m (15 ft) with 7.3 seconds mean period, both of which are acting concurrently in the same direction.
The severest loading condition for vessel’s maneuverability is also to be considered for compliance with
this weather criterion. Compliance with these capability requirements is to be verified by computational
simulations, and the detailed results are to be submitted for approval. The estimated optimum capability is
to be documented in the operating manual, as required in 4-3-5/13.

9 System Design

9.1 Propulsion Machinery and Propulsors

At least two independent propulsion machines are to be provided. As appropriate, a single failure in any
one propulsion machine or auxiliary service system is not to result in propulsion performance inferior to
that required by 4-3-5/7.1 or 4-3-5/7.3, as applicable.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 67
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

9.1.1. R1 Notation
For R1 notation, the propulsion machines and auxiliary service systems may be located in the
same propulsion machinery space and the propulsion machines may drive a single propulsor.
9.1.2 R2 Notation
For R2 notation, at least two propulsors are to be provided such that a single failure of one will
not result in propulsion performance inferior to that required by 4-3-5/7.1 or 4-3-5/7.3, as applicable.
The propulsion machines and auxiliary service systems may, however, be located in the same
propulsion machinery space.
9.1.3 R1-S Notation
For R1-S notation, the propulsion machines and auxiliary service systems are to be separated in
such a way that total loss of any one propulsion machinery space (due to fire or flood) will not
result in propulsion performance inferior to that required by 4-3-5/7.1 or 4-3-5/7.3, as applicable.
The propulsion machines may, however, drive a single propulsor, and the main propulsion gear or
main power transmitting gear is to be located outside the propulsion machinery spaces separated
by a bulkhead meeting the criteria per 4-3-5/9.3.
9.1.4 R2-S Notation
For R2-S notation, at least two propulsors are to be provided, and the propulsion systems are to be
installed in separate spaces such that a single failure in one propulsor or a total loss of any one
propulsion machinery space (due to fire or flood) will not result in propulsion performance inferior
to that required by 4-3-5/7.1 or 4-3-5/7.3, as applicable.

9.3 System Segregation

Where failure is deemed to include loss of a complete propulsion machinery space due to fire or flooding
(R1-S and R2-S notations), redundant components and systems are to be separated by watertight bulkheads
with an A-60 fire classification.
Service access doors which comply with 3-2-7/7.1.1 may be provided between the segregated propulsion
machinery spaces. A means of clear indication of open/closed status of the doors is to be provided in the
bridge and at the centralized control station. Unless specially approved by the flag Administration, these
service access doors are not to be accounted for as the means of escape from the machinery space Category
A required by the requirements of Regulation II-2/13 of SOLAS 1974, as amended.

9.5 Steering Systems

An independent steering system is to be provided for each propulsor. Regardless of the type and the size
of vessel, each steering system is to meet the requirements of Regulation II-1/29.16 of SOLAS 1974, as
amended.
The rudder design is to be such that the vessel can turn in either direction with one propulsion machine or
one steering system inoperable.
For R2-S notation, the steering systems are to be separated such that a fire or flood in one steering compartment
will not affect the steering system(s) in the other compartment(s), and performance in accordance with
4-3-5/7.1 or 4-3-5/7.3, as applicable, is maintained.
For R2 and R2-S notations, in the event of steering system failure, means are to be provided to secure
rudders in the amidships position.

9.7 Auxiliary Service Systems

At least two independent auxiliary service systems, including fuel oil service tanks, are to be provided and
arranged such that a single failure will not result in propulsion performance inferior to that required by
4-3-5/7.1 or 4-3-5/7.3, as applicable. However, a single failure in the vital auxiliary machinery (e.g., pumps,
heaters, etc.), excluding failure of fixed piping, is not to result in reduction of the full propulsion capability.
In order to meet this requirement, it will be necessary to either cross-connect the auxiliary service systems
and size the components (pumps, heaters, etc.) to be capable of supplying two or more propulsion machines
simultaneously, or provide duplicate components (pumps, heaters, etc.) in each auxiliary system in case
one fails.

68 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

With the exception of the fuel oil service tank venting system, interconnections between auxiliary service
systems will be considered, provided that the same are fitted with means (i.e., valves) to disconnect or
isolate the systems from each other.
For R1-S and R2-S notations, the above-mentioned independent auxiliary service systems are to be segregated
in the separate propulsion machinery spaces. With the exception of fuel oil service tank venting systems,
interconnections of auxiliary service systems will be acceptable, provided that the required disconnection
or isolation means are fitted at both sides of the bulkhead separating the propulsion machinery spaces.
Position status of the disconnection or isolation means is to be provided at the navigation bridge and the
centralized control station. Penetrations in the bulkhead separating the propulsion machinery spaces and
steering gear flats (as in the case of R2-S notation) are not to compromise the fire and watertight integrity
of the bulkhead.

9.9 Electrical Distribution Systems

Electrical power generation and distribution systems are to be arranged such that following a single failure
in the systems, the electrical power supply is maintained or immediately restored to the extent that the
requirements in 4-3-5/7 are met.
Where the vessel’s essential equipment is fed from one main switchboard, the bus bars are to be divided
into at least two sections. Where the sections are normally connected, detection of a short circuit on the
bus bars is to result in automatic separation. The circuits supplying equipment essential to the operation of
the propulsion and steering systems are to be divided between the sections such that a loss of one section
will not result in performance inferior to that defined in 4-3-5/7. A fully redundant power management
system is to be provided so that each section of the switchboard can function independently.
For R1-S and R2-S notations, the ship service power generators, their auxiliary systems, the switchboard
sections and the power management systems are to be located in at least two machinery spaces separated
by watertight bulkheads with an A-60 fire classification. The power distribution is to be so arranged that a
fire or flooding of one machinery space is not to result in propulsion capability inferior to that defined in
4-3-5/7. Where an interconnection is provided between the separate propulsion machinery spaces, a
disconnection or isolation means are to be provided at both sides of the bulkhead separating the propulsion
machinery spaces. Position status of the disconnection or isolation means is to be provided at the
navigation bridge and the centralized control station. Fire or flooding of one machinery space is not to
result in propulsion capability inferior to that defined in 4-3-5/7. The power cables from the service
generator(s) in one propulsion machinery space are not to pass through the other propulsion machinery
space containing the remaining service generator(s).
Additionally, for R1-S and R2-S notations, subject to approval by the Administration, the requirements
for self-contained emergency source of power may be considered satisfied without an additional emergency
source of electrical power, provided that:
i) All generating sets and other required sources of emergency source of power are designed to
function at full rated power when upright and when inclined up to a maximum angle of heel in the
intact and damaged condition, as determined in accordance with Part 3, Chapter 3. In no case
need the equipment be designed to operate when inclined more than 22.5° about the longitudinal
axis and/or when inclined 10° about the transverse axis of the vessel.
ii) The generator set(s) installed in each machinery space is of sufficient capacity to meet the requirements
of 4-6-2/3 and 4-6-2/5.
iii) The arrangements required in each machinery space are equivalent to those required by 4-6-2/5.5.2,
4-6-2/5.9 and 4-6-2/5.15, so that a source of electrical power is available at all times for the
services required by 4-6-2/5.

9.11 Control and Monitoring Systems

The control systems are to be operable both independently and in combination from the bridge or the
centralized control station. The mode of operation is to be clearly indicated at each position from which
the propulsion machinery may be controlled.
It is to be possible to locally control the propulsion machinery and the propulsor.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 69
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

For R1-S and R2-S notations, the control and monitoring system for the propulsor (e.g., controllable pitch
propeller control), including all associated cabling, is to be duplicated in each space, and fire or flooding of
one space is not to adversely affect operation of the propulsor from the other space.

9.13 Communication Systems

The requirements of 4-6-2/15 are to be complied with for all installed propulsion control positions.
For R1-S and R2-S notations, the communications cables to each control position are not to be routed
through the same machinery space.

11 Fire Precautions
The requirements of this section apply to Category A machinery spaces only.
Pumps for oil services are to be fitted with shaft sealing devices, which do not require frequent maintenance
to prevent oil leakage, such as mechanical seals.
For R1 and R2 notations, the following requirements are to be complied with in order to minimize the risk
of common damage due to a localized fire in the machinery space.
i) Each auxiliary services system is to be grouped and separated as far as practicable.
ii) Electrical cables supplying power to redundant equipment are to exit the switchboard and be
routed to the equipment, as far apart as practicable.

13 Operating Manual
An operating manual, which is consistent with the information and criteria upon which the classification is
based, is to be placed aboard the vessel for the guidance of the operating personnel. The operating manual
is to give clear guidance to the vessel’s crew about the vessel’s redundancy features and how they may be
effectively and speedily put into service in the event that the vessel’s normal propulsion capability is lost.
The operating manual is to include the following, as a minimum:
i) Vessel’s name and ABS ID number
ii) Simplified diagram and descriptions of the propulsion systems in normal condition
iii) Simplified diagram and descriptions of the propulsion redundancy features
iv) Reduced propulsion capability in terms of estimated worst sea-states which the vessel may
withstand without drifting (for vessels with + in the Class Notation)
v) Test results for the vessel’s maneuverability at reduced speed (for vessels without + in the Class
Notation).
vi) Step-by-step instructions for the use of the redundancy features
vii) Description of the communication systems
viii) Detailed instructions for local propulsion machinery control
The operating manual is to be submitted for review by the American Bureau of Shipping solely to ensure
the presence of the above information, which is to be consistent with the design information and limitations
considered in the vessel’s classification. The American Bureau of Shipping is not responsible for the
operation of the vessel.
Any modifications made to the existing propulsion systems are to be approved by ABS. The operating
manual is to be updated accordingly and submitted to ABS for review.

70 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 3 Propulsion and Maneuvering Machinery
Section 5 Propulsion Redundancy 4-3-5

15 Test and Trial

During the sea trial, the propulsion and steering capability are to be tested in accordance with an approved
test program to verify compliance with this Section.

15.1 Fault Simulation Test

Simulation tests for the redundancy arrangements are to be carried out to verify that, upon any single failure,
the propulsion and steering systems remain operational, or the back-up propulsion and steering systems
may be speedily brought into service.

15.3 Communication System Test

The effectiveness of the communication systems, as required in 4-3-5/9.13 above, is to be tested to verify
that local control of the propulsion systems may be carried out satisfactorily.

17 Survey After Construction

The surveys after construction are to be in accordance with the applicable requirements as contained in the
ABS Rules for Surveys After Construction (Part 7).

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 71
PART Chapter 4: Pumps and Piping Systems

4
CHAPTER 4 Pumps and Piping Systems

CONTENTS
SECTION 1 General .................................................................................................. 79
1 Construction and Installation.............................................................79
1.1 General Requirements...................................................................79
1.3 Piping Groups ................................................................................79
3 Plans and Data to Be Submitted.......................................................79
3.1 Plans..............................................................................................79
3.3 All Piping Systems .........................................................................79
3.5 Booklet of Standard Details ...........................................................79
5 Material Tests and Inspection ...........................................................80
5.1 Specifications and Purchase Orders..............................................80
5.3 Special Materials ...........................................................................80
7 Definitions .........................................................................................80
7.1 Piping/Piping Systems ...................................................................80
7.3 Joints .............................................................................................80
7.5 Fittings ...........................................................................................80
7.7 Positive Closing Valves .................................................................80
7.9 Recognized Standard of Construction ...........................................80
7.11 Standard or Extra-Heavy Pipe .......................................................80
9 General Installation Details ...............................................................81
9.1 Protection ......................................................................................81
9.3 Pipes Near Switchboards ..............................................................81
9.5 Expansion or Contraction Stresses................................................81
9.7 Molded Expansion Joints...............................................................81
9.9 Bulkhead, Deck or Tank Top Penetrations ....................................82
9.11 Collision-Bulkhead Penetrations ....................................................82
9.13 Sluice Valves and Cocks ...............................................................83
9.15 Relief Valves..................................................................................83
9.17 Instruments....................................................................................83
9.19 Flexible Hoses ...............................................................................83
9.21 Control of Static Electricity.............................................................86
9.23 Leakage Containment....................................................................86

SECTION 2 Pumps, Pipes, Valves and Fittings ..................................................... 87

1 Pumps ...............................................................................................87
1.1 General..........................................................................................87
1.3 Hydrostatic Test.............................................................................87
1.5 Capacity Test.................................................................................87
1.7 Relief Valve Capacity Test.............................................................87

72 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 3 Pressure Tests..................................................................................88
3.1 General.......................................................................................... 88
3.3 Fuel Oil Service System ................................................................ 88
3.5 Fuel Oil Suction and Transfer Lines .............................................. 88
3.7 Starting Air Piping.......................................................................... 88
3.9 Hydraulic Power Piping ................................................................. 88
3.11 All Piping ....................................................................................... 88
3.13 Specific Systems ........................................................................... 88
3.15 Hydrostatic Tests of Shell Valves .................................................. 88
3.17 Pneumatic Tests in Lieu of Hydrostatic Tests................................ 88
5 Metallic Pipes....................................................................................89
5.1 Test and Inspection of Group I Piping ........................................... 89
5.3 Steel Pipe ...................................................................................... 89
5.5 Copper Pipe .................................................................................. 89
5.7 Brass Pipe ..................................................................................... 89
5.9 Design ........................................................................................... 89
5.11 Working Pressure and Thickness – Alternative Consideration ...... 90
7 Plastic Pipes .....................................................................................91
7.1 General.......................................................................................... 91
7.3 Plans and Data to be Submitted.................................................... 91
7.5 Design ........................................................................................... 92
7.7 Installation of Plastic Pipes............................................................ 95
7.9 Manufacturing of Plastic Pipes ...................................................... 96
7.11 Plastic Pipe Bonding Procedure Qualification ............................... 97
7.13 Tests by the Manufacturer – Fire Endurance Testing of Plastic
Piping in the Dry Condition (For Level 1 and Level 2) ..................... 97
7.15 Test by Manufacturer – Fire Endurance Testing of Water-Filled
Plastic Piping (For Level 3).............................................................. 99
7.17 Tests by Manufacturer – Flame Spread ...................................... 101
7.19 Testing By Manufacturer – General............................................. 101
7.21 Testing Onboard After Installation ............................................... 101
9 Material of Valves and Fittings........................................................105
9.1 General........................................................................................ 105
9.3 Forged or Cast Steel ................................................................... 105
9.5 Cast Iron...................................................................................... 105
9.7 Ductile (Nodular) Iron .................................................................. 105
9.9 Brass and Bronze........................................................................ 106
9.11 Plastic.......................................................................................... 106
11 Valves .............................................................................................106
11.1 General........................................................................................ 106
11.3 Construction ................................................................................ 106
11.5 Hydrostatic Test and Identification .............................................. 107
13 Pipe Fittings ....................................................................................107
13.1 General........................................................................................ 107
13.3 Hydrostatic Test and Identification .............................................. 107
13.5 Nonstandard Fittings ................................................................... 107
13.7 Mechanical Joints........................................................................ 107
15 Welded Nonstandard Valves and Fittings.......................................108

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 73
 17 Flanges ...........................................................................................108
17.1 General........................................................................................108
17.3 Group I Piping Flanges ................................................................108
17.5 Group II Piping Flanges ...............................................................108
17.7 Group II Plastic Piping Flanges....................................................108
19 Sea Inlets and Overboard Discharges............................................108
19.1 Installation ...................................................................................108
19.3 Valve Connections to Shell..........................................................108
19.5 Materials ......................................................................................109
19.7 Shell Reinforcement ....................................................................109
19.9 Common Overboard Discharge ...................................................109
21 Machinery and Pumping Systems ..................................................109
21.1 Valves Required ..........................................................................109
21.3 Sea Chests ..................................................................................109
23 Scuppers and Drains ......................................................................109
23.1 General........................................................................................109
23.3 Protection from Sea Water Entry .................................................110
23.5 Gravity Drains from Superstructures or Deckhouses...................112
23.7 Vessels Receiving Subdivision Loadlines....................................113
25 Cooler Installations External to the Hull..........................................113
25.1 General........................................................................................113
25.3 Integral Keel Cooler Installations .................................................113
25.5 Non-integral Keel Cooler Installations..........................................113

TABLE 1 Allowable Stress Values S for Steel Piping .............................91

TABLE 2 Fire Endurance Requirements Matrix for Plastic Pipes ........102
TABLE 3 Standards for Plastic Pipes – Typical Requirements for All
Systems ................................................................................104
TABLE 4 Standards for Plastic Pipes – Additional Requirements
Depending on Service and/or Location of Piping..................105

FIGURE 1 Fire Endurance Test Burner Assembly ...................................99

FIGURE 2 Fire Endurance Test Stand with Mounted Sample ...............100
FIGURE 3 Overboard Discharges – Valve Requirements .....................111
FIGURE 4 SOLAS Vessels – Overboard Discharges from Spaces
below Freeboard Deck – Valve Requirements .....................112

SECTION 3 Bilge and Ballast Systems and Tanks .............................................. 114

1 General Arrangement of Bilge Systems .........................................114
3 Bilge Pumps ....................................................................................114
3.1 Number of Pumps........................................................................114
3.3 Capacity.......................................................................................114
3.5 Centrifugal Pumps .......................................................................114
3.7 Independent Power Bilge Pumps.................................................114
5 Bilge and Ballast Piping ..................................................................115
5.1 General........................................................................................115
5.3 Installation ...................................................................................115

74 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 5.5 Manifolds, Cocks and Valves ...................................................... 115
5.7 Strainers ...................................................................................... 116
5.9 Size of Bilge Suctions.................................................................. 116
5.11 Gravity Drains.............................................................................. 117
7 Direct and Emergency Bilge Suctions for Main Machinery
Spaces ............................................................................................117
7.1 Direct Bilge Suction ..................................................................... 117
7.3 Emergency Bilge Suctions........................................................... 117
9 Vent Pipes.......................................................................................117
9.1 General........................................................................................ 117
9.3 Height and Wall Thickness .......................................................... 118
9.5 Size ............................................................................................. 118
9.7 Location....................................................................................... 118
9.9 Vent Outlets................................................................................. 119
11 Overflow Pipes................................................................................121
11.1 General Requirements ................................................................ 121
11.3 Overflows from Combustible and Flammable Liquid Tanks......... 121
11.5 Overflow Common Header .......................................................... 121
13 Sounding .........................................................................................121
13.1 General........................................................................................ 121
13.3 Sounding Pipes ........................................................................... 122
13.5 Gauge Glasses............................................................................ 122
13.7 Level Indicating Systems and Devices ........................................ 123

SECTION 4 Fuel Oil and Lubricating Oil Systems and Tanks ............................ 124
1 Fuel Oil Piping Systems..................................................................124
1.1 General Arrangement .................................................................. 124
1.3 Piping, Valves and Fittings .......................................................... 125
1.5 Oil Heating Arrangements ........................................................... 125
1.7 Multiple Internal Combustion Engine Installations ....................... 126
1.9 Overflows from Combustible and Flammable Liquid Tanks......... 126
3 Fuel Oil Transfer and Filling............................................................126
3.1 General........................................................................................ 126
3.3 Pipes in Oil Tanks ....................................................................... 126
3.5 Control Valves or Cocks .............................................................. 126
3.7 Valves on Oil Tanks .................................................................... 126
3.9 Remote Shutdown of Pumps....................................................... 127
3.11 Oil Drain Tanks............................................................................ 127
5 Fuel Oil Service and Injection Systems ..........................................127
7 Low Flash Point Fuels.....................................................................127
7.1 General........................................................................................ 127
7.3 Fuel Heating ................................................................................ 128
7.5 Fuel Oil Tank Vents ..................................................................... 128
9 Lubricating Oil Systems ..................................................................128
9.1 General........................................................................................ 128
9.3 Sight Flow Glasses...................................................................... 128
9.5 Internal Combustion Engines ...................................................... 128

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 75
 9.7 Reduction Gears..........................................................................128
9.9 Electrical Machinery.....................................................................128
9.11 Hose Reels ..................................................................................128
11 Additional Measures for Oil Pollution Prevention............................128
11.1 General........................................................................................128
11.3 Tank Protection Requirements ....................................................129
11.5 Class Notation – POT ..................................................................130

FIGURE 1 Acceptable Fuel Oil Tanks Arrangements Inside

Category A Machinery Spaces .............................................124

SECTION 5 Internal Combustion Engine Systems .............................................. 131

1 Fuel Oil System...............................................................................131
3 Lubricating Oil System ....................................................................131
5 Cooling Water System ....................................................................131
7 Exhaust Piping ................................................................................131
9 Starting-air Systems........................................................................131

SECTION 6 Hydraulic and Pneumatic Systems ................................................... 132

1 Hydraulic Systems ..........................................................................132
1.1 General........................................................................................132
1.3 Valves..........................................................................................132
1.5 Piping...........................................................................................132
1.7 Pipe Fittings .................................................................................132
1.9 Accumulators and Fluid Power Cylinders ....................................133
1.11 Design Pressure ..........................................................................133
1.13 Segregation of High Pressure Hydraulic Units.............................133
3 Fluid Power Cylinders .....................................................................133
3.1 General........................................................................................133
3.3 Non-compliance with a Recognized Standard .............................133
3.5 Materials ......................................................................................134
3.7 Rudder Actuators.........................................................................134
3.9 Cylinders below Pressures or Temperatures Indicated
in 4-4-6/3.1 ..................................................................................134
3.11 Independently Manufactured and Assembled Units.....................134
5 Pneumatic Systems ........................................................................134
5.1 Application ...................................................................................134
5.3 Pneumatic System Components..................................................134
5.5 Pneumatic System Requirements................................................134

SECTION 7 Cargo Systems ................................................................................... 136

1 Cargo Pumps ..................................................................................136
1.1 Construction ................................................................................136
1.3 Installation ...................................................................................136
1.5 Relief Valve and Bypass..............................................................136
1.7 Pressure Gauges.........................................................................136
1.9 Integrated Cargo and Ballast Systems ........................................136

76 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 3 Cargo Piping Systems ....................................................................136
3.1 General........................................................................................ 136
3.3 Cargo Tank Ballasting ................................................................. 137
3.5 Bow or Stern Loading and Unloading .......................................... 137
3.7 Operating-rod Stuffing Boxes ...................................................... 137
5 Other Piping Systems on Oil Carriers.............................................138
5.1 Pump-room and Cofferdam Bilge Systems ................................. 138
5.3 Machinery Space Bilge System................................................... 138
5.5 Ballast Piping............................................................................... 138
5.7 Piping Through Cargo Tanks....................................................... 139
5.9 Cargo Heating Systems............................................................... 139
5.11 Slop Tanks in Combination Carriers ............................................ 139
5.13 Duct Keels in Double Bottoms..................................................... 139
5.15 Cargo Venting Systems............................................................... 139
5.17 Inert-gas System ......................................................................... 140
5.19 Cargo Vapor Emission Control Systems ..................................... 141
5.21 Crude Oil Washing ...................................................................... 141
7 Cargo Oil Systems on Vessels Other Than Bulk Oil Carrier
Type ................................................................................................141
7.1 Cargo-tank Valves in Dry-cargo Vessels ..................................... 141
7.3 Edible-oil Cargoes ....................................................................... 141
7.5 Venting System for High Flash Point Cargoes ............................ 141
9 Cargo-Handling Systems for Dry Bulk Self-Unloading Vessels......141
9.1 Fail-Safe Arrangements and Safety Devices............................... 141
9.3 Hydraulic Piping Installations....................................................... 141
9.5 Electrical, Control, Alarm and Monitoring Equipment
Installation ................................................................................... 141

SECTION 8 Other Piping Systems and Tanks ..................................................... 142

1 Fixed Oxygen-Acetylene Installations.............................................142
1.1 Application................................................................................... 142
1.3 Gas Storage ................................................................................ 142
1.5 Piping System Components ........................................................ 142
1.7 Testing......................................................................................... 143
3 Fuel Storage and Refueling Systems for Helicopter Facilities........144
3.1 Fuels with Flash Point Above 60°C (140°F) ................................ 144
3.3 Fuels with Flash Point at or Below 60°C (140°F) – Installations
on an Open Deck ........................................................................ 144
3.5 Fuels with Flash Points at or Below 60°C (140°F) – Installation
within Enclosed Spaces............................................................... 144
5 Liquefied Petroleum Gases.............................................................145
5.1 General........................................................................................ 145
5.3 Storage Cylinders........................................................................ 145
5.5 Installation and Testing ............................................................... 145
7 Chemical and Gas Carriers.............................................................146
9 Offshore Support Vessels ...............................................................146

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 77
 11 Ammonia System............................................................................146
11.1 Compartmentation .......................................................................146
11.3 Safety Measures..........................................................................146
11.5 Ammonia Piping...........................................................................146
13 Liquid Mud Cargo Tanks.................................................................146

78 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 1: General

4
CHAPTER 4 Pumps and Piping Systems

SECTION 1 General

1 Construction and Installation

1.1 General Requirements

All vessels are to be provided with the necessary pumps and piping systems for safe and efficient operation
in the service for which they are intended. Materials and workmanship are to be in accordance with good
marine practice and to the satisfaction of the Surveyor. The arrangements and details are to comply with
the following requirements which are applicable to all oceangoing vessels but which may be modified for
vessels classed for limited service.

1.3 Piping Groups (2008)

To distinguish between detail requirements for the various systems, the piping on shipboard is divided into
two groups.
Group I, in general, includes all piping intended for working pressures or temperatures in various services,
as follows:

Service Pressure bar (kgf/cm2, psi) Temperature °C (°F)

Vapor and Gas over 10.3 (10.5, 150) over 343 (650)
Water over 15.5 (15.8, 225) over 177 (350)
Lubricating Oil over 15.5 (15.8, 225) over 204 (400)
Fuel Oil over 10.3 (10.5, 150) over 66 (150)
Hydraulic Fluid over 15.5 (15.8, 225) over 204 (400)

Group II includes all piping intended for working pressures and temperatures below those stipulated under
Group I. Group II also includes cargo-oil and tank cleaning piping in cargo area on oil carriers, and open-
ended lines such as drains, overflows, engine exhausts, boiler escape pipes, and vents, regardless of the
working pressures or temperatures.

3 Plans and Data to Be Submitted

3.1 Plans
Before proceeding with the work, plans in accordance with 4-1-1/7 are to be submitted, showing clearly
the diagrammatic details or arrangement of the equipment.

3.3 All Piping Systems

The plans are to consist of a diagrammatic drawing of each system accompanied by lists of material giving
size, wall thickness, maximum working pressure and material of all pipes and the type, size, pressure rating
and material of valves and fittings.

3.5 Booklet of Standard Details

A booklet of standard piping practices and details, including such items as bulkhead, deck and shell
penetrations, welding details including dimensions, pipe joining details, etc., is to be submitted. Pipe
welding details are to comply with Chapter 4 of the ABS Rules for Materials and Welding (Part 2).

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5 Material Tests and Inspection

5.1 Specifications and Purchase Orders

The appropriate material to be used for the various pipes, valves and fittings is indicated in this section.
The material is to be made in accordance with the requirements of Chapter 3 of the ABS Rules for
Materials and Welding (Part 2), except that tests of material for valves, fittings, fluid power cylinders and
Group II piping need not be witnessed by the Surveyor. Where electric resistance welding is used, the
requirements of Chapter 4 of the above referenced Part 2 are also applicable. Copies in duplicate of the
purchase orders for material requiring test and inspection at the mills or place of manufacture are to be
forwarded to ABS for the information of the Surveyor.

5.3 Special Materials

If it is desired to use special alloys or other materials not covered by the Rules, the use of such materials
will be specially considered for approval.

7 Definitions

7.1 Piping/Piping Systems

The terms Piping and Piping Systems include the pipe, fittings, system joints, method of joining and any
internal or external liners, coverings and coatings required to comply with the performance criteria. For
example, if the basic material needs a fire protective coating to comply with the fire endurance requirements,
then the piping should be manufactured and tested with both the basic material and coating attached, and
details are to be submitted to ABS for approval.

7.3 Joints
The term Joint refers to the method of connecting pipes by adhesive bonding, brazing, welding, bolted
flanging, threading, etc.

7.5 Fittings
The term Fittings refers to bends, elbows, fabricated branch pieces, etc.

7.7 Positive Closing Valves

Positive Closing Valves are valves that are capable of maintaining a set position under all operating conditions.

7.9 Recognized Standard of Construction

Recognized Standards of Construction are published construction standards from organizations, such as
but not limited to the American Society of Mechanical Engineers (ASME), American Society of Testing
and Materials (ASTM), Department of Transportation (DOT), Japanese Industrial Standard (JIS), German
Design Standard (DIN), British Standard Code of Practice (BSI), which are recognized by ABS as being
acceptable standards for a specific purpose or service. Each standard is to be used independently and in a
consistent manner.

7.11 Standard or Extra-Heavy Pipe

Pipe thickness referred to as Standard or Extra-Heavy are the equivalent of American National Standards
Institute Schedule 40 and Schedule 80 pipe up to a maximum wall thickness of 9.5 mm (0.375 in.) and
12.5 mm (0.5 in.), respectively.

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9 General Installation Details

9.1 Protection
Pipes, valves and operating rods are to be effectively secured and adequately protected from mechanical
damage. These protective arrangements are to be fitted so that they may be removed to enable examination
of the pipes, valves and operating rods.

9.3 Pipes Near Switchboards

The leading of pipes in the vicinity of switchboards is to be avoided as far as possible. When such leads are
necessary, care is to be taken to fit no flanges or joints over or near the switchboards unless provision is
made to prevent any leakage from damaging the equipment.

9.5 Expansion or Contraction Stresses (2004)

Provision is to be made to take care of expansion or contraction stresses in pipes due to temperature changes
or working of the hull. Suitable provisions include, but are not limited to, piping bends, elbows, offsets,
changes in direction of the pipe routing or expansion joints. Slip joints of an approved type may be used in
systems and locations where possible leakage will not be hazardous
Where expansion joints are used, the following requirements apply:
• Pipe support. Adjoining pipes are to be suitably supported so that the expansion joints do not carry
any significant pipe weight.
• Alignment. Expansion joints are not to be used to make up for piping misalignment errors. Misalignment
of an expansion joint reduces the rated movements and can induce severe stresses into the joint material,
thus causing reduced service life. Alignment is to be within tolerances specified by the expansion joint
manufacturer.
• Anchoring. Expansion joints are to be installed as close as possible to an anchor point. Where an
anchoring system is not used, control rods may be installed on the expansion joint to prevent excessive
movements from occurring due to pressure thrust of the line.
• Mechanical damage. Where necessary, expansion joints are to be protected against mechanical damage.
• Accessible location. Expansion joints are to be installed in accessible locations to permit regular inspection
and/or periodic servicing.
• Mating flange. Mating flanges are to be clean and usually of the flat faced type. When attaching
beaded end flange expansion joints to raised face flanges, the use of a ring gasket is permitted. Rubber
expansion joints with beaded end flange are not to be installed next to wafer type check or butterfly
valves. Serious damage to the rubber flange bead can result due to lack of flange surface and/or bolt
connection.

9.7 Molded Expansion Joints (2004)

Molded expansion joints may be Type Approved. See 1-1-A3/1 of the ABS Rules for Conditions of
Classification (Part 1).
9.7.1 Circulating Water Systems
Molded expansion fittings of reinforced rubber or other suitable materials may be used in circulating
water piping systems in machinery spaces. Such fittings are to be oil-resistant. The maximum
working pressure is not to be greater than 25% of the hydrostatic bursting pressure of the fitting as
determined by a prototype test. Manufacturer’s name and the month and year of manufacture are
to be embossed or otherwise permanently marked on the outside edge of one of the flanges or
other easily examined area of all flexible expansion joints intended for use in seawater piping
systems over 150 mm (6 in.). Plans of the molded or built-up flexible expansion joints in seawater
piping systems over 150 mm (6 in.), including details of the internal reinforcement arrangements,
are to be submitted for approval.

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9.7.2 Oil Systems

Where molded expansion joints of composite construction utilizing metallic material, such as steel
or stainless steel or equivalent material, with rubberized coatings inside and/or outside or similar
arrangements are proposed for use in oil piping systems (fuel, lubricating, or hydraulic oil), the
following requirements apply:
9.7.2(a) Expansion joint ratings for temperature, pressure, movements and selection of materials
are to be suitable for the intended service.
9.7.2(b) The maximum allowable working pressure of the system is not to be greater than 25% of
the hydrostatic bursting pressure determined by a burst test of a prototype expansion joint. Results
of the burst test are to be submitted.
9.7.2(c) The expansion joints are to pass the fire-resistant test specified in 4-4-1/9.7.3, below.
9.7.2(d) The expansion joints are to be permanently marked with the manufacturer’s name and
the month and year of manufacture.
9.7.3 Fire-Resistant Test
In order for a molded expansion joint of composite construction utilizing metallic material, as
referenced in 4-4-1/9.7.2, to be considered fire-resistant, a prototype of the molded expansion joint is to
be subjected to a fire test for at least 30 minutes at a temperature of not less than 800°C (1472°F) while
water at the maximum service pressure is circulated inside. The temperature of the water at the outlets
is not to be less than 80°C (176°F) during the test. The tested molded expansion joint is to be complete
with end fittings and no leakage is to be recorded during or after the test. In lieu of maximum service
pressure, the fire test may be conducted with the circulating water at a pressure of at least 5 bar
(5.1 kgf/cm2, 72.5 lb/in2), and with a subsequent pressure test to twice the design pressure.

9.9 Bulkhead, Deck or Tank Top Penetrations

Where pipes pass through bulkheads, decks or tank tops, the penetrations are to be made by methods which
will maintain the watertight, fire-tight or smoke-tight integrity of the bulkhead, deck or tank top. Bolted
connections are to have the bolts threaded through the plating, and welded connections are to be welded on
both sides or with full-strength welds from one side.

9.11 Collision-Bulkhead Penetrations (2011)

9.11.1 Allowed Penetrations
A collision bulkhead may be penetrated only as follows:
i) Except as provided in 4-4-1/9.11.1ii), the collision bulkhead may be pierced below the
bulkhead deck by not more than one pipe for dealing with fluid in the forepeak tank, provided
that the pipe is fitted with a screwdown or butterfly valve capable of being operated from
above the bulkhead deck; the valve chest being secured to the collision bulkhead inside
the forepeak.
ii) If the forepeak is divided to hold two kinds of liquids, the collision bulkhead may be pierced
below the margin line by two pipes, each of which is fitted as required by 4-4-1/9.11.1i),
provided there is no practical alternative to the fitting of such a second pipe and that,
having regard to the additional subdivision provided in the forepeak, the safety of the
vessel is maintained.
9.11.2 Penetrations Details
Piping penetrating collision bulkheads is to comply with the following requirements:
i) Pipes piercing the collision bulkhead are to be fitted with suitable valves operable from
above the bulkhead deck and secured to the bulkhead, generally inside the forepeak.
ii) Cast iron is not to be used for these valves. The use of nodular iron, also known as ductile
iron or spheroidal-graphite iron, will be accepted, provided the material has an elongation
not less than 12% in 50 mm (2 in.).
iii) Tanks forward of the collision bulkhead are not to be arranged for the carriage of oil or
other liquid substances that are flammable.

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9.13 Sluice Valves and Cocks

No valve or cock for sluicing purposes is to be fitted on a collision bulkhead. Sluice valves or cocks may
be fitted only on other watertight bulkheads, where they are accessible for examination at all times. The
control rods are to be operable from the bulkhead deck and are to be provided with an indicator to show
whether the valve or cock is open or closed. The control rods are also to be properly protected from injury
and their weight is not to be supported by the valve or cock.

9.15 Relief Valves

All systems which may be exposed to pressures greater than that for which they are designed are to be
safeguarded by suitable relief valves or the equivalent. Pressure containers such as evaporators, heaters,
etc., which may be isolated from a protective device in the line are to have such devices either directly on
the shell or between the shell and the isolation valve.
9.15.1 Exceptions
In pumping systems such as oil piping and fire main, where relief valves are ordinarily required at
the pump, such valves need not be fitted when the system is served only by centrifugal pumps so
designed that the pressure delivered cannot exceed that for which the piping is designed.

9.17 Instruments
9.17.1 Temperature
Thermometers and other temperature sensing devices registering through pressure boundaries are
to be provided with instrument wells to allow for instrument removal without impairing the
integrity of the pressurized system.
9.17.2 Pressure
Pressure sensing devices are to be provided with valve arrangements to allow for instrument
isolation and removal without impairing the pressurized system’s integrity.
9.17.3 Tanks (2006)
Pressure, temperature and level sensing devices installed on tanks at locations where they are
subjected to a static head of liquid are to be fitted with valves or arranged such that they may be
removed without emptying the tank.

9.19 Flexible Hoses (2006)

9.19.1 Definition
A flexible hose assembly is a short length of metallic or non-metallic hose normally with prefabricated
end fittings ready for installation.
9.19.2 Scope
The requirements 4-4-1/9.19 apply to flexible hoses of metallic or non-metallic material intended
for a permanent connection between a fixed piping system and items of machinery. The requirements
may also be applied to temporary connected flexible hoses or hoses of portable equipment.
Flexible hose assemblies as defined in 4-4-1/9.19.1 are acceptable for use in oil fuel, lubricating,
hydraulic and thermal oil systems, fresh water and sea water cooling systems, compressed air systems,
bilge and ballast systems. The flexible hoses are acceptable for steam systems with pressure below
7 bar (7.1 kgf/cm2, 101.5 psi) and temperature below 150°C (302°F), where they comply with
4-4-1/9.19.
Flexible hoses are not acceptable in high pressure fuel oil injection systems.
These requirements for flexible hose assemblies are not applicable to hoses intended to be used in
fixed fire extinguishing systems.

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9.19.3 Design and Construction

9.19.3(a) Hose material. Flexible hoses are to be designed and constructed in accordance with
recognized National or International standards acceptable to ABS. Flexible hoses constructed of
rubber or plastics materials and intended for use in bilge, ballast, compressed air, oil fuel,
lubricating, hydraulic and thermal oil systems are to incorporate a single or double closely woven
integral wire braid or other suitable material reinforcement. Where rubber or plastics materials
hoses are to be used in oil supply lines to burners, the hoses are to have external wire braid
protection in addition to the integral reinforcement. Flexible hoses for use in steam systems are to
be of metallic construction.
9.19.3(b) Hose end fittings. Flexible hoses are to be complete with approved end fittings in
accordance with manufacturer’s specification. Flanged end connections are to comply with 4-4-2/17
and threaded end connections with 4-4-2/13.1, as applicable and each type of hose/fitting combination
is to be subject to prototype testing to the same standard as that required by the hose with particular
reference to pressure and impulse tests.
The use of hose clamps and similar types of end attachments is not acceptable for flexible hoses in
piping systems for steam, flammable media, starting air or for sea water, where failure may result
in flooding*. In other piping systems, the use of hose clamps may be accepted where the working
pressure is less than 5 bar (5.1 kgf/cm2, 72.5 psi) and provided there are double clamps at each end
connection. The hose clamps are to be at least 12 mm (0.5 in.) wide and are not to be dependent
upon spring tension to remain fastened.
* Note: For sea water systems, where flooding can be prevented by the installation of a readily accessible shutoff
valve immediately upstream of the hose, double clamps at each end connection may be accepted.
9.19.3(c) Fire resistance. Flexible hose assemblies constructed of non-metallic materials intended
for installation in piping systems for flammable media and sea water systems where failure may
result in flooding are to be of a fire-resistant type**. Fire resistance is to be demonstrated by
testing to ISO 15540 and ISO 15541.
** Note: The installation of a shutoff valve immediately upstream of a sea water hose does not satisfy the requirement
for fire resistant type hose.
9.19.3(d) Hose application. Flexible hose assemblies are to be selected for the intended location
and application taking into consideration ambient conditions, compatibility with fluids under working
pressure and temperature conditions consistent with the manufacturer’s instructions and other
relevant requirements of this Section.
Flexible hose assemblies intended for installation in piping systems where pressure pulses and/or
high levels of vibration are expected to occur in service, are to be designed for the maximum
expected impulse peak pressure and forces due to vibration. The tests required by 4-4-1/9.19.5 are
to take into consideration the maximum anticipated in-service pressures, vibration frequencies and
forces due to installation.
9.19.4 Installation
In general, flexible hoses are to be limited to a length necessary to provide for relative movement
between fixed and flexibly mounted items of machinery, equipment or systems.
Flexible hose assemblies are not to be installed where they may be subjected to torsion deformation
(twisting) under normal operating conditions.
The number of flexible hoses, in piping systems is to be kept to minimum and is to be limited for
the purpose stated in 4-4-1/9.19.2.
Where flexible hoses are intended to be used in piping systems conveying flammable fluids that
are in close proximity of heated surfaces the risk of ignition due to failure of the hose assembly
and subsequent release of fluids is to be mitigated as far as practicable by the use of screens or
other similar protection.

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Section 1 General 4-4-1

Flexible hoses are to be installed in clearly visible and readily accessible locations (i.e., the hose is
to be located such that inspection can be accomplished without the need to remove any bolted
inspection plate or similar obstruction. A mirror or other means may be used for inspection where
space is limited).
The installation of flexible hose assemblies is to be in accordance with the manufacturer’s
instructions and use limitations with particular attention to the following:
• Orientation
• End connection support (where necessary)
• Avoidance of hose contact that could cause rubbing and abrasion
• Minimum bend radii
9.19.5 Tests
9.19.5(a) Test procedures. Acceptance of flexible hose assemblies is subject to satisfactory
prototype testing. Prototype test programmes for flexible hose assembles are to be submitted by
the manufacturer and are to be sufficiently detailed to demonstrate performance in accordance
with the specified standards.
The tests are, as applicable, to be carried out on different nominal diameters of hose type complete
with end fittings for pressure, burst, impulse resistance and fire resistance in accordance with the
requirements of the relevant standard. The following standards are to be used as applicable.
• ISO 6802 – Rubber and plastics hoses and hose assemblies – Hydraulic pressure impulse test
without flexing.
• ISO 6803 – Rubber and plastics hoses and hose assemblies – Hydraulic pressure impulse test
with flexing.
• ISO 15540 – Ships and marine technology – Fire resistance of hose assemblies – Test methods.
• ISO 15541 – Ships and marine technology – Fire resistance of hose assemblies – Requirements
for test bench.
• ISO 10380 – Pipework – Corrugated metal hoses and hose assemblies.
Other standards may be accepted where agreed.
9.19.5(b) Burst test. All flexible hose assemblies are to be satisfactorily prototype burst tested to
an international standard to demonstrate they are able to withstand a pressure not less than four (4)
times its design pressure without indication of failure or leakage.
Note: The international standards (e.g., EN or SAE for burst testing of non-metallic hoses) require the pressure
to be increased until burst without any holding period at 4 x MWP.

9.19.6 Marking
Flexible hoses are to be permanently marked by the manufacturer with the following details:
• Hose manufacturer’s name or trademark.
• Date of manufacture (month/year).
• Designation type reference.
• Nominal diameter.
• Pressure rating
• Temperature rating.
Where a flexible hose assembly is made up of items from different manufacturers, the components
are to be clearly identified and traceable to evidence of prototype testing.

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9.21 Control of Static Electricity

Cargo tanks and cargo piping systems carrying flammable liquids and piping systems that are routed
through hazardous areas are to be suitably grounded either by welding or bolting the tanks, pipes or their
supports directly to the hull of the vessel or through the use of bonding straps. In general, the resistance
between ground points along the length, across joints, and from pipe to ground is not to exceed 1 megohm.
Where bonding straps are used, they are to be clearly visible, protected from mechanical damage and of a
type not affected by corrosive product and paint. Bonding straps are required for cargo tanks and piping
systems which are not permanently connected to the hull, including independent cargo tanks, cargo tanks
and piping systems which are electrically separated from the hull, and pipe connections arranged for
removal of spool pieces. The foregoing is not applicable to tank containers.
Components of alarms and level indicating devices located within cargo tanks are to be designed to account
for conductivity.

9.23 Leakage Containment

For areas where leakage may be expected, such as oil burners, purifiers, oil drains, valves under day tanks,
etc., means of containing the leakage are to be provided. Where drain pipes are fitted for collected leakages,
they are to be led to a suitable oil drain tank not forming part of an overflow system.

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PART Section 2: Pumps, Pipes, Valves and Fittings

4
CHAPTER 4 Pumps and Piping Systems

SECTION 2 Pumps, Pipes, Valves and Fittings

1 Pumps

1.1 General (2011)

For self-propelled vessels 500 gross tons and above, the following pumps are to meet the test requirements
of 4-4-2/1.3 and 4-4-2/1.5:
• Fire pump, including emergency fire pump
• Other fire fighting service pumps, such as, pumps for fixed water-based systems, or equivalent, local
application fire-fighting systems, sprinkler systems, deck foam systems, etc.
• Bilge pump
• Ballast pump
• Hydraulic pumps for steering gears, anchor windlasses and variable pitch propellers
• Pumps associated with inert gas systems, i.e.:
Fuel oil pumps for boilers/inert gas generators
Cooling water pumps for flue gas scrubber
The tests are to be carried out at the manufacturer’s plant in the presence of the Surveyor. The capacity test
will not be required nor will the hydrostatic test need to be witnessed by the Surveyor for individual pumps
assembled on a production line basis, provided the Surveyor is satisfied from periodic inspections and from
the manufacturer’s quality assurance procedures that the pump capacities are acceptable and that hydrostatic
testing is being performed. See 4-1-1/3. For pumps associated with reciprocating internal combustion
engines and reduction gears, see 4-2-1/19.

1.3 Hydrostatic Test

All pumps are to be hydrostatically tested to 1.5P, but not less than 3.9 bar (4 kgf/cm2, 57 psi), where P is
the maximum working pressure of the part concerned. When the suction and discharge sides of the pump
are tested independently, the pump suction is to be tested to 1.5 times Ps, but not less than 3.9 bar (4
kgf/cm2, 57 psi), where Ps is the maximum pressure available from the system at the suction inlet. For
steering gear pumps, also see 4-3-3/15.1.

1.5 Capacity Test

Pump capacities are to be checked with the pump operating at design conditions (rated speed and pressure
head). For centrifugal pumps, the pump characteristic (head capacity) design curve is to be verified to the
satisfaction of the Surveyor.

1.7 Relief Valve Capacity Test (2005)

For positive displacement pumps with an integrated relief valve, the valve’s setting and full flow capacity
corresponding to the pump maximum rating is to be verified. The operational test for relief valve capacity
may be waived if previous satisfactory tests have been carried out on similar pumps.

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3 Pressure Tests (2002)

3.1 General
In addition to the testing and inspection of materials, as required in Chapter 3 of the ABS Rules for
Materials and Welding (Part 2), the following tests on the fabricated piping are to be witnessed by the
Surveyor after bending and the attachment of flanges.
Small bore pipes and tubes of less than 15 mm outside diameter may be exempted from the required
hydrostatic tests.

3.3 Fuel Oil Service System

Pressure lines are to be tested before installation to 1.5 times the design pressure of the system, but not less
than 3.4 bar (3.5 kgf/cm2, 50 psi).

3.5 Fuel Oil Suction and Transfer Lines

Transfer systems and fuel oil suction lines are to be tested before installation to 3.4 bar (3.5 kgf/cm2, 50 psi).

3.7 Starting Air Piping

Piping in starting-air systems is to be tested, preferably before installation, to 1.5 times the design pressure
of the system.

3.9 Hydraulic Power Piping

After fabrication, the hydraulic power piping system or each piping component is to be tested to 1.5 times
the design pressure. For steering gear piping tests, see 4-3-3/15. For controllable pitch propeller system
piping, a test, including a check of relief valve operation, is to be performed after installation in the presence
of the Surveyor.

3.11 All Piping

After installation, all piping is to be tested under working conditions.
Where it is not possible to carry out the required hydrostatic tests for all segments of pipes and integral
fittings before installation, the remaining segments, including the closing seams, may be so tested after
installation. Or, where it is intended to carry out all of the required hydrostatic tests after installation, such
tests may be conducted in conjunction with those required by this paragraph. In both of these respects,
testing procedures are to be submitted to the Surveyor for acceptance.

3.13 Specific Systems

3.13.1 Gas and Liquid Fuel Systems and Heating Coils in Tanks
The following piping systems are to be hydrostatically tested in the presence of the Surveyor to
1.5P, but not less than 4 bar (4.1 kgf/cm2, 58 psi), after installation:
i) Gas and liquid fuel systems
ii) Heating coils in tanks

3.15 Hydrostatic Tests of Shell Valves

All valves intended for installation on the side shell at or below the load waterline, including those at the
sea chests, are to be hydrostatically tested before installation and in the presence of the Surveyor to a
pressure of at least 5 bar (5.1 kgf/cm2, 72.5 psi).

3.17 Pneumatic Tests in Lieu of Hydrostatic Tests

In general, a pneumatic test in lieu of a hydrostatic test is not permitted. Where it is impracticable to carry out
the required hydrostatic test, a pneumatic test may be considered. In such cases, the procedure for carrying
out the pneumatic test, having regard to safety of personnel, is to be submitted to the Surveyor for review.

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5 Metallic Pipes

5.1 Test and Inspection of Group I Piping

Pipes intended for use in Group I piping systems are to be tested in the presence of and inspected by the
Surveyor in accordance with Chapter 3 of the ABS Rules for Materials and Welding (Part 2) or such other
appropriate material specification as may be approved in connection with a particular design. See 4-4-6/1.5
for pipe used in hydraulic systems.

5.3 Steel Pipe

5.3.1 Seamless Pipe
Seamless-drawn steel pipe may be used for all purposes.
5.3.2 Welded Pipe
Electric-resistance-welded steel pipe may be used for temperatures up to 343°C (650°F).
Consideration will be given to the use of electric-resistance-welded (ERW) pipe for use above
343°C (650°F) where the material is shown to be suitable for the intended service (i.e. in a non-
corrosive environment where the design temperature is below the lowest graphitization temperature
specified for the material, etc.). Furnace butt-welded pipe up to and including 115 mm O.D. (4 in.
NPS) may be used for Group II piping for temperatures up to 232°C (450°F), but is not to be used
for flammable or combustible fluids.

5.5 Copper Pipe

Seamless-drawn and welded copper pipe, unless otherwise prohibited, may be used for all purposes where
the temperature does not exceed 208°C (406°F) and within the limitations specified in the material specification.

5.7 Brass Pipe

Seamless-drawn brass pipe, unless otherwise prohibited, may be used where the temperature does not exceed
208°C (406°F).

5.9 Design
5.9.1 Maximum Allowable Working Pressure and Minimum Thickness
The maximum allowable working pressure and the minimum thickness of pipes are to be determined
by the following equations, with due consideration being given to the reduction in thickness at the
outer radius of bent pipes:
KS (t − C ) WD
W= t= +C
D − M (t − C ) KS + MW
where
W = maximum allowable working pressure, in bar, kgf/cm2 (psi). See Note 1.
t = minimum thickness of pipe, in mm (in.). See Note 5.
K = 20 (200, 2)
D = actual external diameter of pipe, in mm (in.)
S = maximum allowable fiber stress, in N/mm2 (kgf/mm2, psi) from 4-4-2/Table 1.
See Note 2.
M = factor from 4-4-2/Table 1

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C = allowance for threading, grooving or mechanical strength

= 1.65 mm (0.065 in.) for plain-end steel or wrought-iron pipe or tubing up to
115 mm O.D. (4 in. NPS). See Note 3.
= 0.00 mm (0.000 in.) for plain-end steel or wrought-iron pipe or tubing up to
115 mm O.D. (4 in. NPS) used for hydraulic piping systems. See Note 3.
= 0.00 mm (0.000 in.) for plain-end steel or wrought-iron pipe or tubing 115 mm
O.D. (4 in. NPS) and larger. See Note 3.
= 1.27 mm (0.05 in.) for all threaded pipe 17 mm O.D. (3/8 in.) and smaller
= depth of thread, h, for all threaded pipe over 17 mm O.D. (3/8 in.). See Note 4.
= depth of groove for grooved pipe
= 0.00 mm (0.000 in.) for plain-end nonferrous pipe or tubing. See Note 3.
Notes:
1 The value of W used in the equations is to be not less than 8.6 bar (8.8 kgf/cm2, 125 psi),
except that for suction and other low-pressure piping of nonferrous material, the actual
working pressure may be applied if a suitable addendum is provided against erosion
and outside damage. However, in no case is the value of W to be less than 3.4 bar
(3.5 kgf/cm2, 50 psi) for use in the equations.
2 Values of S for other materials are not to exceed the stress permitted by ASME B31.1
Code for Pressure Piping, Power Piping.
3 Plain-end pipe or tubing includes those joined by any method in which the wall thickness
is not reduced.
4 The depth of thread, h, may be determined by the equation h = 0.8/n where n is the
number of threads per inch, or in metric units by the equation h = 0.8n where n is the
number of mm per thread.
5 If pipe is ordered by its nominal wall thickness, the manufacturing tolerance on wall
thickness is to be taken into account.

5.9.2 Pipe Bending (2005)

Pipe bending is to be in accordance with 2-3-12/25 of the ABS Rules for Materials and Welding
(Part 2). Alternatively, bending in accordance with a recognized standard (e.g., ASME B31.1-
Section 129.1 and 129.3) or other approved specification to a radius that will result in a surface
free of cracks and substantially free of buckles may be acceptable.

5.11 Working Pressure and Thickness – Alternative Consideration

Consideration will be given to the maximum allowable working pressure and the minimum thickness of
piping determined from criteria of applicable recognized standards.

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TABLE 1
Allowable Stress Values S for Steel Piping N/mm2 (kgf/mm2, psi)
Part 2, Chapter 3, Service Temperature—Degrees C (F)
Section 12/Paragraph
No. and (Grade) −29°C (−20°F) to
Nominal Composition Tensile Strength 334°C (650°F) 372°C (700°F) 399°C (750°F) 427°C (800°F)
M = 0.8 M = 0.8 M = 0.8 M = 0.8
2-3-12/5.1 (Gr. 1) 310 46.9 46.6
Elec. res. Carbon Steel (31.5, 45000) (4.78, 6800) (4.75, 6500)
2-3-12/5.1 (Gr. 2) 330 70.3 68.3 62.8 53.1
Elec. res. Carbon Steel (33.7, 48000) (7.17, 10200) (6.96, 9900) (6.40, 9100) (5.41, 7700)
330 82.8 80.6 73.7 62.1
Seamless Carbon Steel (33.7, 48000) (8.44, 12000) (8.22, 11700) (7.52, 10700) (6.33, 9000)
2-3-12/5.1 (Gr. 3) 415 88.3 84.1 75.8 63.4
Elec. res. Carbon Steel (42, 60000) (9.0, 12800) (8.58, 12200) (7.73, 11000) (6.47, 9200)
415 103.5 99.2 89.6 74.4
Seamless Carbon Steel (42, 60000) (10.55, 15000) (10.12, 14400) (9.14, 13000) (7.59, 10800)
2-3-12/5.3 (Gr. 4) 330 82.8 80.7 73.7 62.1
Carbon Steel (33.7, 48000) (8.44, 12000) (8.23, 11700) (7.52, 10700) (6.33, 9000)
2-3-12/5.3 (Gr. 5) 415 103.5 99.2 89.6 74.4
Carbon Steel (42, 60000) (10.55, 15000) (10.12, 14400) (9.14, 13000) (7.59, 10800)

Notes:
1 Intermediate values of S may be determined by interpolation.
2 For grades of piping other than those given in 4-4-2/Table 1, S values are not to exceed those permitted by
ASTM B31.1 Code for Pressure Piping. See 4-4-2/5.11.
3 Consideration is to be given to the possibility of graphite formation in carbon steel at temperatures above
425°C (800°F).

7 Plastic Pipes

7.1 General
Pipes and piping components made of thermoplastic or thermosetting plastic materials with or without
reinforcement may be used in piping systems referred to in 4-4-2/Table 2 subject to compliance with the
following requirements. For the purpose of these Rules, “plastic” means both thermoplastic and thermosetting
plastic materials with or without reinforcement, such as polyvinyl chloride (PVC) and fiber reinforced
plastics (FRP).

7.3 Plans and Data to be Submitted (2007)

Rigid plastic pipes are to be in accordance with a recognized national or international standard acceptable
to ABS. Specification for the plastic pipe, including thermal and mechanical properties and chemical
resistance, is to be submitted for review together with the spacing of the pipe supports.
The following information for the plastic pipes, fittings and joints is to be submitted for approval.
7.3.1 General Information
i) Pipe and fitting dimensions
ii) Maximum internal and external working pressure
iii) Working temperature range
iv) Intended services and installation locations
v) Level of fire endurance

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vi) Electrically conductive

vii) Intended fluids
viii) Limits on flow rates
ix) Serviceable life
x) Installation instructions
xi) Details of marking
7.3.2 Drawings and Supporting Documentation
i) Certificates and reports for relevant tests previously carried out.
ii) Details of relevant standards.
iii) All relevant design drawings, catalogues, data sheets, calculations and functional descriptions.
iv) Fully detailed sectional assembly drawings showing pipe, fittings and pipe connections.
7.3.3 Materials
i) Resin type.
ii) Catalyst and accelerator types and concentration employed in the case of reinforced polyester
resin pipes or hardeners where epoxide resins are employed.
iii) A statement of all reinforcements employed where the reference number does not identify
the mass per unit area or the tex number of a roving used in a filament winding process,
these are to be detailed.
iv) Full information regarding the type of gel-coat or thermoplastic liner employed during
construction, as appropriate.
v) Cure/post-cure conditions. The cure and post-cure temperatures and times employ for
given resin/reinforcement ratio.
vi) Winding angle and orientation.

7.5 Design
7.5.1 Internal Pressure
A pipe is to be designed for an internal pressure not less than the design pressure of the system in
which it will be used. The maximum internal pressure, Pint, for a pipe is to be the lesser of the
following:
Psth Plth
Pint = Pint =
4 2.5
where
Psth = short-term hydrostatic test failure pressure
Plth = long-term hydrostatic test failure pressure (> 100,000 hours)
The hydrostatic tests are to be carried out under the following standard conditions:
• Atmospheric pressure = 1 bar (1 kgf/cm2, 14.5 psi)
• Relative humidity = 30%
• Fluid temperature = 25°C (77°F)
The hydrostatic test failure pressure may be verified experimentally or determined by a combination
of testing and calculation methods which are to be submitted to ABS for approval.

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7.5.2 External Pressure

External pressure is to be considered for any installation which may be subject to vacuum conditions
inside the pipe or a head of liquid on the outside of the pipe. A pipe is to be designed for an external
pressure not less than the sum of the pressure imposed by the maximum potential head of liquid
outside the pipe plus full vacuum, 1 bar (1 kgf/cm2, 14.5 psi), inside the pipe. The maximum external
pressure for a pipe is to be determined by dividing the collapse test pressure by a safety factor of 3.
The collapse test pressure may be verified experimentally or determined by a combination of testing
and calculation methods which are to be submitted to ABS for approval.
7.5.3 Axial Strength
7.5.3(a) The sum of the longitudinal stresses due to pressure, weight and other dynamic and
sustained loads is not to exceed the allowable stress in the longitudinal direction. Forces due to
thermal expansion, contraction and external loads, where applicable, are to be considered when
determining longitudinal stresses in the system.
7.5.3(b) In the case of fiber reinforced plastic pipes, the sum of the longitudinal stresses is not to
exceed one-half of the nominal circumferential stress derived from the maximum internal pressure
determined according to 4-4-2/7.5, unless the allowable longitudinal stress is verified experimentally
or by a combination of testing and calculation methods.
7.5.4 Temperature (2007)
The maximum allowable working temperature of a pipe is to be in accordance with the manufacturer’s
recommendations, but in each case, it is to be at least 20°C (36°F) lower than the minimum heat
distortion temperature of the pipe material determined according to ISO 75 method A or equivalent.
The minimum heat distortion temperature is not to be less than 80°C (176°F). This minimum heat
distortion temperature requirement is not applicable to pipes and pipe components made of
thermoplastic materials, such as polyethylene (PE), polypropylene (PP), polybutylene (PB) and
intended for non-essential services.
Where low temperature services are considered, special attention is to be given with respect to
material properties.
7.5.5 Impact Resistance
Plastic pipes and joints are to have a minimum resistance to impact in accordance with a recognized
national or international standard such as ASTM D2444 or equivalent. After the impact resistance
is tested, the specimen is to be subjected to hydrostatic pressure equal to 2.5 times the design
pressure for at least one hour.
7.5.6 Fire Endurance
4-4-2/Table 2 specifies fire endurance requirements for pipes based upon system and location.
Pipes and their associated fittings whose functions or integrity are essential to the safety of the
vessel are to meet the indicated fire endurance requirements which are described below.
i) Level 1 will ensure the integrity of the system during a full scale hydrocarbon fire and is
particularly applicable to systems where loss of integrity may cause outflow of flammable
liquids and worsen the fire situation. Piping having passed the fire endurance test specified
in 4-4-2/7.13 for a duration of a minimum of one hour without loss of integrity in the dry
condition is considered to meet Level 1 fire endurance standard (L1).
ii) Level 2 intends to ensure the availability of systems essential to the safe operation of the
vessel, after a fire of short duration, allowing the system to be restored after the fire has been
extinguished. Piping having passed the fire endurance test specified in 4-4-2/7.13 for a
duration of a minimum of 30 minutes without loss of integrity in the dry condition is
considered to meet Level 2 fire endurance standard (L2).
iii) Level 3 is considered to provide the fire endurance necessary for a water filled piping system
to survive a local fire of short duration. The system’s functions are capable of being restored
after the fire has been extinguished. Piping having passed the fire endurance test specified
in 4-4-2/7.15 for a duration of a minimum of 30 minutes without loss of integrity in the
wet condition is considered to meet Level 3 fire endurance standard (L3).

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Where a fire protective coating of pipes and fittings is necessary for achieving the fire endurance
standards required, the following requirements apply.
i) Pipes are generally to be delivered from the manufacturer with the protective coating applied,
with on-site application limited to that necessary for installation purposes (i.e., joints).
See 4-4-2/7.7.7 regarding the application of the fire protection coating on joints.
ii) The fire protection properties of the coating are not to be diminished when exposed to salt
water, oil or bilge slops. It is to be demonstrated that the coating is resistant to products
likely to come in contact with the piping.
iii) In considering fire protection coatings, such characteristics as thermal expansion, resistance
against vibrations and elasticity are to be taken into account.
iv) The fire protection coatings are to have sufficient resistance to impact to retain their integrity.
v) (2007) Random samples of pipe are to be tested to determine the adhesion qualities of the
coating to the pipe.
7.5.7 Flame Spread
7.5.7(a) Plastic Pipes. All pipes, except those fitted on open decks and within tanks, cofferdams,
void spaces, pipe tunnels and ducts, are to have low flame spread characteristics. The test procedures
in IMO Resolution A.653(16) Recommendation on Improved Fire Test Procedures for Surface
Flammability of Bulkhead, Ceiling, and Deck Finish Materials, modified for pipes as indicated in
4-4-2/7.17, are to be used for determining the flame spread characteristics. Piping materials giving
average values for all of the surface flammability criteria not exceeding the values listed in
Resolution A.653(16) are considered to meet the requirements for low flame spread.
Alternatively, flame spread testing in accordance with ASTM D635 may be used in lieu of the
IMO flame spread test, provided such test is acceptable to the Administration.
7.5.7(b) Multi-core Metallic Tubes Sheathed by Plastic Materials (2005). The multi-core tubes
in “bundles” made of stainless steel or copper tubes covered by an outer sheath of plastic material
are to comply with the flammability test criteria of IEC 60332, Part 3, Category A/F or A/F/R.
Alternatively, the tube bundles complying with at least the flammability test criteria of IEC 60332,
Part 1 or a test procedure equivalent thereto are acceptable provided they are installed in compliance
with approved fire stop arrangements.
7.5.8 Electrical Conductivity
7.5.8(a) Piping conveying fluids with a conductivity less than 1000 pico siemens per meter are to
be electrically conductive.
7.5.8(b) Regardless of the fluid being conveyed, plastic pipes are to be electrically conductive if
the piping passes through a hazardous area.
7.5.8(c) Where electrically conductive pipe is required, the resistance per unit length of the pipes
and fittings is not to exceed 1 × 105 Ohm/m (3 × 104 Ohm/ft). See also 4-4-2/7.7.4.
7.5.8(d) If the pipes and fittings are not homogeneously conductive, the conductive layers are to
be protected against the possibility of spark damage to the pipe wall.
7.5.9 Marking (2007)
Plastic pipes and other components are to be permanently marked with identification in accordance
with a recognized standard. Identification is to include pressure ratings, the design standard that
the pipe or fitting is manufactured in accordance with, the material with which the pipe or fitting is
made, and the date of fabrication.

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7.7 Installation of Plastic Pipes

7.7.1 Supports
7.7.1(a) Selection and spacing of pipe supports in shipboard systems are to be determined as a
function of allowable stresses and maximum deflection criteria. Support spacing is not to be greater
than the pipe manufacturer’s recommended spacing. The selection and spacing of pipe supports
are to take into account pipe dimensions, mechanical and physical properties of the pipe material,
mass of pipe and contained fluid, external pressure, operating temperature, thermal expansion effects,
loads due to external forces, thrust forces, water hammer and vibrations to which the system may
be subjected. Combinations of these loads are to be checked.
7.7.1(b) Each support is to evenly distribute the load of the pipe and its contents over the full
width of the support. Measures are to be taken to minimize wear of the pipes where they contact
the supports.
7.7.1(c) Heavy components in the piping system such as valves and expansion joints are to be
independently supported.
7.7.1(d) The supports are to allow for relative movement between the pipes and the vessel’s
structure, having due regard for the difference in the coefficients of thermal expansion and
deformations of the vessel’s hull and its structure.
7.7.1(e) When calculating the thermal expansion, the system working temperature and the
temperature at which assembling is performed are to be taken into account.
7.7.2 External Loads
When installing the piping, allowance is to be made for temporary point loads, where applicable.
Such allowances are to include at least the force exerted by a load (person) of 980 N (100 kgf, 220 lbf)
at mid-span on any pipe more than 100 mm (4 in.) nominal diameter.
Pipes are to be protected from mechanical damage where necessary.
7.7.3 Plastic Pipe Connections
7.7.3(a) The strength of fittings and joints is not to be less than that of the piping they connect.
7.7.3(b) Pipes may be joined using adhesive-bonded, welded, flanged or other joints.
7.7.3(c) Tightening of flanged or mechanically coupled joints is to be performed in accordance
with manufacturer’s instructions.
7.7.3(d) Adhesives, when used for joint assembly, are to be suitable for providing a permanent
seal between the pipes and fittings throughout the temperature and pressure range of the intended
application.
Joining techniques are to be in accordance with manufacturer’s installation guidelines. Personnel
performing these tasks are to be qualified to the satisfaction of ABS, and each bonding procedure
is to be qualified before shipboard piping installation commences. Requirements for joint bonding
procedures are in 4-4-2/7.11.
7.7.4 Electrical Conductivity
Where electrically conductive pipe is required by 4-4-2/7.5.8, installation of the pipe is to be in
accordance with the following:
7.7.4(a) The resistance to earth (ground) from any point in the system is not to exceed 1 meg-
ohm. The resistance is to be checked in the presence of the Surveyor.
7.7.4(b) Pipes and fittings with conductive layers are to be protected against a possibility of spark
damage caused by a different conductivity of the conductive layers.
7.7.4(c) Where used, earthing wires or bonding straps are to be accessible for inspection. The
Surveyor is to verify that they are in visible locations.

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7.7.5 Shell Connections

Where plastic pipes are permitted in systems connected to the shell of the vessel, the valves and
the pipe connection to the shell are to be metallic. The side shell valves are to be arranged for
remote control from outside the space in which the valves are located. For further details of the
shell valve installation, their connections and material, refer to 4-4-2/19.
7.7.6 Bulkhead and Deck Penetrations
7.7.6(a) The integrity of watertight bulkheads and decks is to be maintained where plastic pipes
pass through them.
7.7.6(b) Where plastic pipes pass through “A” or “B” class divisions, arrangements are to be made
to ensure that the fire endurance is not impaired. These arrangements are to be tested in accordance
with IMO Resolution. A 754 (18), Recommendation on Fire Resistance Tests for “A”, “B” and
“F” Class Divisions, as amended.
7.7.6(c) If the bulkhead or deck is also a fire division and destruction by fire of plastic pipes may
cause inflow of liquid from a tank, a metallic shut-off valve operable from above the bulkhead
deck is to be fitted at the bulkhead or deck.
7.7.7 Application of Fire Protection Coatings
Fire protection coatings are to be applied on the joints, where necessary for meeting the required
fire endurance criteria in 4-4-2/7.5.6, after performing hydrostatic pressure tests of the piping
system (see 4-4-42/7.19). The fire protection coatings are to be applied in accordance with the
manufacturer’s recommendations, using a procedure approved in each particular case.

7.9 Manufacturing of Plastic Pipes (1 July 2009)

The manufacturer is to have a quality system and be certified in accordance with 1-1-A3/5.3 and 1-1-A3/5.5
of the ABS Rules for Conditions of Classification (Part 1) or ISO 9001 (or equivalent). The quality system
is to consist of elements necessary to ensure that pipes and components are produced with consistent and
uniform mechanical and physical properties in accordance with recognized standards and including testing
to demonstrate the compliance of plastic pipes, fittings and joints with 4-4-2/7.5.1 through 4-4-2/7.5.8 and
4-4-2/7.19, as applicable.
Where the manufacturer does not have a certified quality system in accordance with 1-1-A3/5.3 and 1-1-A3/5.5
of the ABS Rules for Conditions of Classification (Part 1) or ISO 9001 (or equivalent), the tests in with
4-4-2/7.5.1 through 4-4-2/7.5.8 and 4-4-2/7.19, as applicable, will be required using samples from each batch
of pipes being supplied for use aboard the vessel and are to be carried out in the presence of the Surveyor.
Each length of pipe and each fitting is to be tested at the manufacturer’s production facility to a hydrostatic
pressure not less than 1.5 times the maximum allowable internal pressure of the pipe in 4-4-2/7.5.1.
Alternatively, for pipes and fittings not employing hand lay up techniques, the hydrostatic pressure test
may be carried out in accordance with the hydrostatic testing requirements stipulated in the recognized
national or international standard to which the pipe or fittings are manufactured, provided that there is an
effective quality system in place.
Depending upon the intended application, ABS reserves the right to require the hydrostatic pressure testing
of each pipe and/or fitting.
If the facility does not have a certified quality system in accordance with 1-1-A3/5.3 and 1-1-A3/5.5 of the
ABS Rules for Conditions of Classification (Part 1) or ISO 9001 (or equivalent), then the production
testing must be witnessed by the Surveyor.
The manufacturer is to provide documentation certifying that all piping and piping components supplied
are in compliance with the requirements of Section 4-4-2.

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7.11 Plastic Pipe Bonding Procedure Qualification

7.11.1 Procedure Qualification Requirements
7.11.1(a) To qualify joint bonding procedures, the tests and examinations specified herein are to
be successfully completed. The procedure for making bonds is to include the following:
i) Materials used
ii) Tools and fixtures
iii) Environmental requirements
iv) Joint preparation requirements
v) Cure temperature
vi) Dimensional requirements and tolerances
vii) Test acceptance criteria for the completed assembly
7.11.1(b) Any change in the bonding procedure which will affect the physical and mechanical
properties of the joint will require the procedure to be requalified.
7.11.2 Procedure Qualification Testing
7.11.2(a) A test assembly is to be fabricated in accordance with the procedure to be qualified and
it is to consist of at least one pipe-to-pipe joint and one pipe-to-fitting joint. When the test assembly
has been cured, it is to be subjected to a hydrostatic test pressure at a safety factor of 2.5 times the
design pressure of the test assembly for not less than one hour. No leakage or separation of joints
is to be allowed. The test is to be conducted so that the joint is loaded in both the longitudinal and
circumferential direction.
7.11.2(b) Selection of the pipes used for test assembly is to be in accordance with the following:
i) When the largest size to be joined is 200 mm (8 in.) nominal outside diameter or smaller,
the test assembly is to be the largest pipe size to be joined.
ii) When the largest size to be joined is greater than 200 mm (8 in.) nominal outside diameter,
the size of the test assembly is to be either 200 mm (8 in.) or 25% of the largest piping
size to be joined, whichever is greater.
7.11.2(c) When conducting performance qualifications, each bonder and each bonding operator
are to make up test assemblies, the size and number of which are to be as required above.

7.13 Tests by the Manufacturer – Fire Endurance Testing of Plastic Piping in the Dry Condition
(For Level 1 and Level 2)
7.13.1 Test Method
7.13.1(a) The specimen is to be subjected to a furnace test with fast temperature increase similar
to that likely to occur in a fully developed liquid hydrocarbon fire. The time/temperature is to be
as follows:

at the end of 5 minutes 945°C (1733°F)

at the end of 10 minutes 1033°C (1891°F)
at the end of 15 minutes 1071°C (1960°F)
at the end of 30 minutes 1098°C (2008°F)
at the end of 60 minutes 1100°C (2012°F)

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7.13.1(b) The accuracy of the furnace control is to be as follows:

i) During the first 10 minutes of the test, variation in the area under the curve of mean furnace
temperature is to be within ±15% of the area under the standard curve.
ii) During the first 30 minutes of the test, variation in the area under the curve of mean furnace
temperature is to be within ±10% of the area under the standard curve.
iii) For any period after the first 30 minutes of the test, variation in the area under the curve
of mean furnace temperature is to be within ±5% of the area under the standard curve.
iv) At any time after the first 10 minutes of the test, the difference in the mean furnace
temperature from the standard curve is to be within ±100°C (±180°F).
7.13.1(c) The locations where the temperatures are measured, the number of temperature
measurements and the measurement techniques are to be approved by ABS.
7.13.2 Test Specimen
7.13.2(a) The test specimen is to be prepared with the joints and fittings intended for use in the
proposed application.
7.13.2(b) The number of specimens is to be sufficient to test typical joints and fittings including
joints between non-metal and metal pipes and metal fittings to be used.
7.13.2(c) The ends of the specimen are to be closed. One of the ends is to allow pressurized
nitrogen to be connected. The pipe ends and closures may be outside the furnace.
7.13.2(d) The general orientation of the specimen is to be horizontal and it is to be supported by
one fixed support with the remaining supports allowing free movement. The free length between
supports is not to be less than 8 times the pipe diameter.
7.13.2(e) Most materials will require a thermal insulation to pass this test. The test procedure is to
include the insulation and its covering.
7.13.2(f) If the insulation contains or is liable to absorb moisture, the specimen is not to be tested
until the insulation has reached an air dry-condition, defined as equilibrium with an ambient
atmosphere of 50% relative humidity at 20 ±5°C (68 ±9°F). Accelerated conditioning is permissible,
provided the method does not alter the properties of the component material. Special samples are
to be used for moisture content determination and conditioned with the test specimen. These
samples are to be so constructed as to represent the loss of water vapor from the specimen having
similar thickness and exposed faces.
7.13.3 Test Condition
A nitrogen pressure inside the test specimen is to be maintained automatically at 0.7 ± 0.1 bar
(0.7 ± 0.1 kgf/cm2, 10 ± 1.5 psi) during the test. Means are to be provided to record the pressure
inside the pipe and the nitrogen flow into and out of the specimen in order to indicate leakage.
7.13.4 Acceptance Criteria
7.13.4(a) During the test, no nitrogen leakage from the sample is to occur.
7.13.4(b) After termination of the furnace test, the test specimen together with fire protective
coating, if any, is to be allowed to cool in still air to ambient temperature and then tested to the
maximum allowable pressure of the pipes, as defined in 4-4-2/7.5.1 and 4-4-2/7.5.2. The pressure
is to be held for a minimum of 15 minutes without leakage. Where practicable, the hydrostatic test
is to be conducted on bare pipe (i.e., coverings and insulation removed) so that any leakage will be
apparent.
7.13.4(c) Alternative test methods and/or test procedures considered to be at least equivalent,
including open pit testing method, may be accepted in cases where the pipes are too large for the
test furnace.

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7.15 Test by Manufacturer – Fire Endurance Testing of Water-Filled Plastic Piping (For Level 3)
7.15.1 Test Method
7.15.1(a) A propane multiple burner test with a fast temperature increase is to be used.
7.15.1(b) For piping up to and including 152 mm (6 in.) O.D., the fire source is to consist of two
rows of five burners, as shown in 4-4-2/Figure 1. A constant heat flux averaging 113.6 kW/m2
(36,000 BTU/hr-ft2) ± 10% is to be maintained 12.5 ± 1 cm (5 ± 0.4 in.) above the centerline of
the burner array. This flux corresponds to a pre-mix flame of propane with a fuel flow rate of 5
kg/hr (11 lb/hr) for a total heat release of 65 kW (3700 BTU/min.). The gas consumption is to be
measured with an accuracy of at least ±3% in order to maintain a constant heat flux. Propane with
a minimum purity of 95% is to be used.
7.15.1(c) For piping greater than 152 mm (6 in.) O.D., one additional row of burners is to be
included for each 51 mm (2 in.) increase in pipe diameter. A constant heat flux averaging
113.6 kW/m2 (36,000 BTU/hr-ft2) ± 10% is still to be maintained at the 12.5 ± 1 cm (5 ± 0.4 in.)
height above the centerline of the burner array. The fuel flow is to be increased as required to
maintain the designated heat flux.
7.15.1(d) The burners are to be type “Sievert No. 2942” or equivalent which produces an air
mixed flame. The inner diameter of the burner heads is to be 29 mm (1.14 in.). See 4-4-2/Figure 1.
The burner heads are to be mounted in the same plane and supplied with gas from a manifold. If
necessary, each burner is to be equipped with a valve in order to adjust the flame height.
7.15.1(e) The height of the burner stand is also to be adjustable. It is to be mounted centrally
below the test pipe with the rows of burners parallel to the pipe’s axis. The distance between the
burner heads and the pipe is to be maintained at 12.5 ± 1 cm (5 ± 0.4 in.) during the test. The free
length of the pipe between its supports is to be 0.8 ± 0.05 m (31.5 ± 2 in.). See 4-4-2/Figure 2.

FIGURE 1
Fire Endurance Test Burner Assembly
50
90 +

+ 70

70 +

+ 70
70 +
420
+ 70

70 + 32
+ 70

70 + 85

+ 90
50

20 60 20 100
100
a) Top View b) Side View of
one Burner

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FIGURE 2
Fire Endurance Test Stand with Mounted Sample
1500 ± 100
800 ± 50

125 ± 10

7.15.2 Test Specimen

7.15.2(a) Each pipe is to have a length of approximately 1.5 m (5 ft).
7.15.2(b) The test pipe is to be prepared with permanent joints and fittings intended to be used.
Only valves and straight joints versus elbows and bends are to be tested as the adhesive in the joint
is the primary point of failure.
7.15.2(c) The number of pipe specimens is to be sufficient to test all typical joints and fittings.
7.15.2(d) The ends of each pipe specimen are to be closed. One of the ends is to allow pressurized
water to be connected.
7.15.2(e) If the insulation contains or is liable to absorb moisture, the specimen is not to be tested
until the insulation has reached an air dry-condition, defined as equilibrium with an ambient
atmosphere of 50% relative humidity at 20 ± 5°C (68 ± 9°F). Accelerated conditioning is permissible,
provided the method does not alter the properties of the component material. Special samples are
to be used for moisture content determination and conditioned with the test specimen. These samples
are to be so constructed as to represent the loss of water vapor from the specimen having similar
thickness and exposed faces.
7.15.2(f) The pipe samples are to rest freely in a horizontal position on two V-shaped supports.
The friction between pipe and supports is to be minimized. The supports may consist of two stands,
as shown in 4-4-2/Figure 2.
7.15.2(g) A relief valve is to be connected to one of the end closures of each specimen.
7.15.3 Test Conditions
7.15.3(a) The test is to be carried out in a sheltered test site in order to prevent any draft influencing
the test.
7.15.3(b) Each pipe specimen is to be completely filled with dearated water to exclude air bubbles.
7.15.3(c) The water temperature is not to be less than 15°C (59°F) at the start and is to be measured
continuously during the test. The water is to be stagnant and the pressure maintained at 3 ±0.5 bar
(3.1 ± 0.5 kgf/cm2, 43.5 ± 7.25 psi) during the test.
7.15.4 Acceptance Criteria
7.15.4(a) During the test, no leakage from the sample(s) is to occur except that slight weeping
through the pipe wall may be accepted.
7.15.4(b) After termination of the burner test, the test specimen together with fire protective coating,
if any, is to be allowed to cool to ambient temperature and then tested to the maximum allowable
pressure of the pipes, as defined in 4-4-2/7.5.1 and 4-4-2/7.5.2. The pressure is to be held for a
minimum of 15 minutes without significant leakage [i.e., not exceeding 0.2 1/min. (0.05 gpm)].
Where practicable, the hydrostatic test is to be conducted on bare pipe (i.e., coverings and
insulation removed) so that any leakage will be apparent.

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7.17 Tests by Manufacturer – Flame Spread

7.17.1 Test Method
Flame spread of plastic piping is to be determined by IMO Resolution A.653(16) entitled,
“Recommendation on Improved Fire Test Procedures for Surface Flammability of Bulkhead,
Ceiling, and Deck Finish Materials” with the following modifications.
7.17.1(a) Tests are to be made for each pipe material and size.
7.17.1(b) The test sample is to be fabricated by cutting pipes lengthwise into individual sections
and then assembling the sections into a test sample as representative as possible of a flat surface.
A test sample is to consist of at least two sections. The test sample is to be at least 800 ±5 mm
(31.5 ±0.2 in.) long. All cuts are to be made normal to the pipe wall.
7.17.1(c) The number of sections that must be assembled together to form a test sample is to be
that which corresponds to the nearest integral number of sections which makes up a test sample
with an equivalent linearlized surface width between 155 mm (6 in.) and 180 mm (7 in.). The
surface width is defined as the measured sum of the outer circumference of the assembled pipe
sections that are exposed to the flux from the radiant panel.
7.17.1(d) The assembled test sample is to have no gaps between individual sections.
7.17.1(e) The assembled test sample is to be constructed in such a way that the edges of two
adjacent sections coincide with the centerline of the test holder.
7.17.1(f) The individual test sections are to be attached to the backing calcium silicate board
using wire (No. 18 recommended) inserted at 50 mm (2 in.) intervals through the board and tightened
by twisting at the back.
7.17.1(g) The individual pipe sections are to be mounted so that the highest point of the exposed
surface is in the same plane as the exposed flat surface of a normal surface.
7.17.1(h) The space between the concave unexposed surface of the test sample and the surface of
the calcium silicate backing board is to be left void.
7.17.1(i) The void space between the top of the exposed test surface and the bottom edge of the
sample holder frame is to be filled with a high temperature insulating wool if the width of the pipe
segments extend under the side edges of the sample holding frame.

7.19 Testing By Manufacturer – General (2007)

Testing is to demonstrate the compliance of plastic pipes, fittings and joints for which approval, in accordance
with Section 4-4-2, is requested. These tests are to be in compliance with the requirements of relevant
standards as per 4-4-2/Table 3 and 4-4-2/Table 4.

7.21 Testing Onboard After Installation

Piping systems are to be subjected to a hydrostatic test pressure of not less than 1.5 times the design
pressure to the satisfaction of the Surveyor.
For piping required to be electrically conductive, earthing is to be checked and random resistance testing is
to be conducted to the satisfaction of the Surveyor.

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TABLE 2
Fire Endurance Requirements Matrix for Plastic Pipes
LOCATION
PIPING SYSTEMS A B C D E F G H I J K
CARGO (Flammable cargoes with flash point ≤60°C (140°F)
1 Cargo lines NA NA L1 NA NA 0 NA 0 (10) 0 NA L1 (2)
(10)
2 Crude oil washing lines NA NA L1 NA NA 0 NA 0 0 NA L1 (2)
3 Vent lines NA NA NA NA NA 0 NA 0 (10) 0 NA X
INERT GAS
4 Water seal effluent line NA NA 0 (1) NA NA 0 (1) 0 (1) 0 (1) 0 (1) NA 0
(1) (1)
5 Scrubber effluent line 0 0 NA NA NA NA NA NA 0 (1) NA 0
6 Main line 0 0 L1 NA NA NA NA NA 0 NA L1 (6)
7 Distribution lines NA NA L1 NA NA 0 NA NA 0 NA L1 (2)
FLAMMABLE LIQUIDS (flash point > 60°C (140°F)
8 Cargo lines X X L1 X X NA (3) 0 010 0 NA L1
9 Fuel oil X X L1 X X NA (3) 0 0 0 L1 L1
10 Lubricating oil X X L1 X X NA NA NA 0 L1 L1
11 Hydraulic oil X X L1 X X 0 0 0 0 L1 L1
SEA WATER (See Note 1)
12 Bilge main and branches L1 (7) L1 (7) L1 X X NA 0 0 0 NA L1
13 Fire main and water spray L1 L1 L1 X NA NA NA 0 0 X L1
14 Foam system L1 L1 L1 NA NA NA NA NA 0 L1 L1
15 Sprinkler system L1 L1 L3 X NA NA NA 0 0 L3 L3
16 Ballast L3 L3 L3 L3 X 0 (10) 0 0 0 L2 L2
17 Cooling water, essential services L3 L3 NA NA NA NA NA 0 0 NA L2
18 Tank cleaning services, fixed machines NA NA L3 NA NA 0 NA 0 0 NA L3 (2)
19 Non-essential systems 0 0 0 0 0 NA 0 0 0 0 0
FRESH WATER
20 Cooling water, essential services L3 L3 NA NA NA NA 0 0 0 L3 L3
21 Condensate return L3 L3 L3 0 0 NA NA NA 0 0 0
22 Non-essential systems 0 0 0 0 0 NA 0 0 0 0 0
SANITARY/DRAINS/SCUPPERS
23 Deck drains (internal) L1 (4) L1 (4) NA L1 (4) 0 NA 0 0 0 0 0
24 Sanitary drains (internal) 0 0 NA 0 0 NA 0 0 0 0 0
25 Scuppers and discharges (overboard) 0 (1,8) 0 (1,8) 0 (1,8) 0 (1,8) 0 (1,8) 0 0 0 0 0 (1,8) 0
VENTS/SOUNDING
26 Water tanks/dry spaces 0 0 0 0 0 0 (10) 0 0 0 0 0
27 Oil tanks (flashpoint 60°C (140°F)) X X X X X X3 0 0 (10) 0 X X
MISCELLANEOUS
28 Control air L1 (5) L1 (5) L1 (5) L1 (5) L1 (5) NA 0 0 0 L1 (5) L1 (5)
29 Service air (non-essential) 0 0 0 0 0 NA 0 0 0 0 0
30 Brine 0 0 NA 0 0 NA NA NA 0 0 0
31 Auxiliary low pressure steam (pressure L2 L2 0 (9) 0 (9) 0 (9) 0 0 0 0 0 (9) 0 (9)
≤ 7 bar (7 kgf/cm2, 100 psi))
Locations Abbreviations
A Category A machinery spaces L1 Fire endurance test in dry conditions, 60 minutes, in
B Other machinery spaces accordance with 4-4-2/7.13
C Cargo pump rooms L2 Fire endurance test in dry conditions, 30 minutes, in
D Ro/Ro cargo holds accordance with 4-4-2/7.13
E Other dry cargo holds L3 Fire endurance test in wet conditions, 30 minutes, in
F Cargo tanks accordance with 4-4-2/7.15
G Fuel oil tanks 0 No fire endurance test required
H Ballast water tanks NA Not applicable
I Cofferdams, void spaces, pipe tunnels and ducts X Metallic materials having a melting point greater than 925°C
J Accommodation, service and control spaces (1700°F)
K Open decks

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TABLE 2 (continued)
Fire Endurance Requirements Matrix for Plastic Pipes
Notes:
1 Where non-metallic piping is used, remotely controlled valves are to be provided at the vessel’s side. These valves
are to be controlled from outside the space.
2 Remote closing valves are to be provided at the cargo tanks.
3 When cargo tanks contain flammable liquids with a flash point greater than 60°C (140°F), “0” may replace “NA”
or “X”.
4 For drains serving only the space concerned, “0” may replace “L1”.
5 When controlling functions are not required by statutory requirements, “0” may replace “L1”.
6 For pipe between machinery space and deck water seal, “0” may replace “L1”.
7 For passenger vessels, “X” is to replace “L1”.
8 Scuppers serving open decks in positions 1 and 2, as defined in Regulation 13 of the International Convention on
Load Lines, 1966, are to be “X” throughout, unless fitted at the upper end with the means of closing capable of
being operated from a position above the freeboard deck in order to prevent downflooding.
9 For essential services such as fuel oil tank heating and ship’s whistle, “X” is to replace “0”.
10 For tankers where compliance with paragraph 3(f) of Regulation 13F of Annex I of MARPOL 73/78 is required,
“NA” is to replace “0”.

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TABLE 3
Standards for Plastic Pipes – Typical Requirements for All Systems (2007)
Test Typical Standard Notes
1 Internal pressure (1) 4-4-2/7.5.1 Top, Middle, Bottom (of each
ASTM D 1599, pressure range)
ASTM D 2992 Tests are to be carried out on pipe
spools made of different pipe sizes,
ISO 15493 or equivalent fittings and pipe connections.
2 External pressure (1) 4-4-2/7.5.2 As above, for straight pipes only.
ISO 15493 or equivalent
3 Axial strength (1) 4-4-2/7.5.3 As above.
4 Load deformation ASTM D 2412 or equivalent Top, Middle, Bottom (of each
pressure range)
5 Temperature limitations (1) 4-4-2/7.5.4 Each type of resin
ISO 75 Method A GRP piping system:
HDT test on each type of resin acc. to
ISO 75 method A.
Thermoplastic piping systems:
ISO 75 Method AISO 306 Plastics –
Thermoplastic materials –
Determination of Vicat softening
temperature (VST)
VICAT test according to ISO 2507
Polyesters with an HDT below 80°C
should not be used.
6 Impact resistance (1) 4-4-2/7.5.5 Representative sample of each type of
ISO 9854: 1994, ISO 9653: 1991 ISO construction
15493
ASTM D 2444, or equivalent
7 Ageing Manufacturer's standard Each type of construction
ISO 9142:1990
8 Fatigue Manufacturer’s standard or service Each type of construction
experience.
9 Fluid absorption ISO 8361:1991
10 Material compatibility (2) ASTM C581
Manufacturer’s standard
Notes:
1 Where the manufacturer does not have a certified quality system, test to be witnessed by the Surveyor. See 4-4-2/7.9.
2 If applicable.

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TABLE 4
Standards for Plastic Pipes – Additional Requirements
Depending on Service and/or Location of Piping (2007)
Test Typical Standard Notes
(1,2)
1 Fire endurance 4-4-2/7.5.6 Representative samples of each type
of construction and type of pipe
connection.
2 Flame spread (1,2) 4-4-2/7.5.7 Representative samples of each type
of construction.
3 Smoke generation (2) IMO Fire Test Procedures Code Representative samples of each type
of construction.
4 Toxicity (2) IMO Fire Test Procedures Code Representative samples of each type
of construction.
5 Electrical conductivity (1,2) 4-4-2/7.5.8 Representative samples of each type
ASTM F1173-95 or ASTM of construction
D 257, NS 6126/ 11.2 or equivalent
Notes:
1 Where the manufacturer does not have a certified quality system, test to be witnessed by the Surveyor. See 4-4-2/7.9.
2 If applicable.

Note: Test items 1, 2 and 5 in 4-4-2/Table 4 are optional. However, if not carried out, the range of approved
applications for the pipes will be limited accordingly (see 4-4-2/Table 2).

9 Material of Valves and Fittings

9.1 General
The physical characteristics of such material are to be in accordance with the applicable requirements of
Chapter 3 of the ABS Rules for Materials and Welding (Part 2) or other such appropriate material specifications
as may be approved in connection with a particular design for the stresses and temperatures to which they
may be exposed. Manufacturers are to make physical tests of each melt and, upon request, are to submit
the results of such tests to ABS.

9.3 Forged or Cast Steel

In any system, forged or cast steel may be used in the construction of valves and fittings for all pressures
and temperatures. Consideration is to be given to the possibility of graphite formation in the following steels:
Carbon steel above 425°C (800°F); carbon-molybdenum steel above 468°C (875°F); chrome-molybdenum
steel (with chromium under 0.60%) above 524°C (975°F).

9.5 Cast Iron

For temperatures not exceeding 232°C (450°F), cast iron of the physical characteristics specified in Section
2-3-6 of the ABS Rules for Materials and Welding (Part 2) may be used in the construction of valves and
fittings, except in locations for which it is specifically prohibited elsewhere in the Rules.

9.7 Ductile (Nodular) Iron

Nodular-iron applications for valves will be specially considered when the material has an elongation of
not less than 12% in 50 mm (2 in.) and where the temperature does not exceed 343°C (650°F). See Section
2-3-5 of the ABS Rules for Materials and Welding (Part 2).

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9.9 Brass and Bronze

Brass or bronze having the physical characteristics as specified in Chapter 3 of the ABS Rules for Materials
and Welding (Part 2) may be used in the construction of valves and fittings intended for temperatures up to
208°C (406°F). For temperatures greater than 208°C (406°F) but not in excess of 288°C (550°F), high-
temperature bronze is to be used and the chemical and physical characteristics are to be submitted for approval.
Valves, fittings and flanges of nonferrous material may be attached to nonferrous pipe by an approved
soldering method. For pressures up to 6.9 bar (7 kgf/cm2, 100 psi) and temperatures not exceeding 93°C
(200°F), ordinary solder may be used, but for higher pressures and temperatures, the method and the quality
of solder to be used will be considered for each case.

9.11 Plastic
Rigid plastic compounds for valves and fittings in plastic piping systems will be considered for Group II
piping systems. The design pressure and temperature together with the physical characteristics of the
material verifying compliance with the requirements of 4-4-2/7 are to be submitted in all cases.

11 Valves

11.1 General
11.1.1 Standard Valves
Valves constructed and tested in accordance with a recognized standard may be used, subject to
compliance with 4-4-2/11.5.
11.1.2 Non-Standard Valves
All other valves not certified by the manufacturer as being in accordance with a recognized standard
may be accepted based on evidence verifying their suitability for the intended service. Acceptable
evidence includes testing or analysis demonstrating adequacy including both structural and material
capability aspects. Drawings of such valves showing details of construction and materials are to be
submitted for review, as well as the basis for valve pressure rating, such as design calculations or
appropriate burst test data.

11.3 Construction
All valves are to close with a right hand (clockwise) motion of the handwheel when facing the end of the
stem and are to be either of the rising-stem type or fitted with an indicator to show whether the valve is
open or closed.
All valves of Group I piping systems having nominal diameters exceeding 50 mm (2 in.) are to have
bolted, pressure seal or breech lock bonnets and flanged or welding ends. Welding ends are to be the butt
weld type, except that socket weld ends may be used for valves having nominal diameters of 80 mm (3 in.)
or less, up to and including 39.2 bar (40.0 kgf/cm2) pressure rating class (ASME 600 Class), and for valves
having nominal diameters of 65 mm (2.5 in.) or less, up to and including 98.1 bar (100 kgf/cm2) pressure
rating class (ASME 1500 Class).
All cast iron valves are to have bolted bonnets or are to be of the union bonnet type. For cast iron valves of
the union bonnet type, the bonnet ring is to be of steel, bronze or malleable iron.
Stems, discs or disc faces, seats and other wearing parts of valves are to be of corrosion-resistant materials
suitable for the intended service.
Valves are to be designed for the maximum pressure to which they will be subjected. The design pressure
is to be at least 3.4 bar (3.5 kgf/cm2, 50 psi). Valves used in open systems, such as vent and drain lines, (for
example, level gauge and drain cocks) may be designed for a pressure below 3.4 bar (3.5 kg/cm2, 50 psi),
subject to the requirements of 4-4-2/11.1. Large fabricated ballast manifolds which connect lines exceeding
200 mm (8 in.) nominal pipe size may be used when the maximum pressure to which they will be subjected
does not exceed 1.7 bar (1.75 kgf/cm2, 25 psi).

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All valves for Group I piping systems and valves intended for use in oil lines are to be constructed so that
the stem is positively restrained from being screwed out of the body (bonnet). Plug valves, butterfly valves
and valves employing resilient material will be subject to special consideration. Valve operating systems
for all valves which cannot be manually operated are to be submitted for approval.

11.5 Hydrostatic Test and Identification

All valves are to be subjected by the manufacturer to a hydrostatic test at a pressure equal to that stipulated
by the American National Standards Institute or other recognized standard. They are to bear the trademark
of the manufacturer legibly stamped or cast on the exterior of the valve and the primary pressure rating at
which the manufacturer identifies the valve as meeting the requirements of the standards.

13 Pipe Fittings

13.1 General
All fittings in Group I piping are to have flanged or welded ends in sizes over 89 mm O.D. (3 in. N.P.S.).
Screwed fittings may be used in Group I piping systems, provided the temperature does not exceed 496°C
(925°F) and the pressure does not exceed the maximum pressure indicated below for the pipe size.

Pipe Size Maximum Pressure

mm O.D. (in. N.P.S.) bar (kgf/cm2, psi)
above 89 (3) not permitted in Group I piping service
above 60 (2) through 89 (3) 27.6 (28.10, 400)
above 33 (1) through 60 (2) 41.4 (42.20, 600)
above 27 (0.75) through 33 (1) 82.8 (84.40, 1200)
27 (0.75) and smaller 103 (105.50, 1500)

Flared, flareless and compression fittings may be used for tube sizes not exceeding 60 mm O.D. (2 in.
NPS) in Group I piping. In Group II piping, screwed fittings, flared, flareless and compression tube fittings
will be accepted without size limitations. Flared fittings are to be used for flammable fluid systems, except
that both flared and flareless fittings of the non-bite type may be used when the tubing system is of steel or
nickel-copper or copper-nickel alloys. Only flared fittings are to be used when tubing for flammable fluid
systems is of copper or copper-zinc alloys. See 4-4-6/1.7 for hydraulic systems.

13.3 Hydrostatic Test and Identification

All fittings are to be subjected by the manufacturer to a hydrostatic test at a pressure equal to that
stipulated by the American National Standards Institute or other recognized standard. They are to bear the
trademark of the manufacturer legibly stamped or cast on the exterior of the fitting and also the primary
pressure rating at which the manufacturer guarantees the fitting to meet the requirements of the standards.

13.5 Nonstandard Fittings

Fittings which are not certified by the manufacturer as being in accordance with a recognized standard may
be accepted based on evidence verifying their suitability for the intended service. Acceptable evidence
includes testing or analysis demonstrating adequacy including both structural and material capability
aspects. Drawings of such fittings showing details of construction, material and design calculations or test
results are to be submitted for review.

13.7 Mechanical Joints (2005)

The installation of mechanical pipe joints, as covered by 4-4-2/13.1 and 4-4-2/13.5, is to be in accordance
with the manufacturer’s assembly instructions. Where special tools and gauges are required for installation
of the joints, these are to be specified and supplied as necessary by the manufacturer. These special tools
are to be kept onboard.

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15 Welded Nonstandard Valves and Fittings

Non-Standard steel valves and fittings fabricated by means of fusion welding are to also comply with the
requirements of Chapter 4 of the ABS Rules for Materials and Welding (Part 2). However, after a
manufacturer’s procedure in the fabrication of equipment of this kind has been demonstrated by tests to the
satisfaction of an ABS Surveyor, subsequent tests on the product need not be witnessed, but the manufacturer’s
guarantee that the Rules are complied with will be accepted as to other valves and fittings which conform
to standards of the American National Standards Institute or other recognized standards.

17 Flanges

17.1 General
Flanges are to be designed and fabricated in accordance with a recognized standard. Slip-on flanges from
flat plate may be substituted for hubbed slip-on flanges in Group II piping systems.

17.3 Group I Piping Flanges

In Group I piping, flanges may be attached to the pipes by any of the following methods appropriate for the
material involved:
17.3.1 Steel Pipe
Over 60 mm O.D. (2 in. NPS) steel pipes are to be expanded into steel flanges, or they may be
screwed into the flanges and seal-welded. They may in all cases be attached by fusion welding in
compliance with the requirements of 2-4-2/9. Smaller pipes may be screwed without seal-welding,
but oil lines are, in addition, to be expanded into the flanges in order to insure uniformly tight threads.
17.3.2 Nonferrous Pipe
In Group I, nonferrous pipes are to be brazed to composition metallic or steel flanges, and in sizes
of 60 mm O.D. (2 in. NPS) and under, they may be screwed.

17.5 Group II Piping Flanges

Similar attachments are also to be used in Group II piping. However, modifications are permitted for welded
flanges, as noted in 2-4-2/9.5 and 2-4-2/9.7, and screwed flanges of suitable material may be used in all sizes.

17.7 Group II Plastic Piping Flanges

Rigid plastic compounds for flanges in plastic piping systems will be considered for Group II piping
systems. The design pressure and temperature together with the physical characteristics of the material are
to be submitted in all cases.

19 Sea Inlets and Overboard Discharges

19.1 Installation (2006)

Piping connections bolted to the shell plating are to have the bolt heads countersunk on the outside and the
bolts threaded through the plating. Where a reinforcing ring of sufficient thickness is welded to the inside
of the shell, studs may be used. For compensation in way of holes in the shell plating, see 3-2-2/11.
Threaded connections outboard of the shell valves are not considered an acceptable method of connection
pipe to the shell.

19.3 Valve Connections to Shell

Pipe connections fitted between the shell and the valves are to be of substantial construction (i.e., pipe wall
thickness is to be equal to the shell plating thickness, but need not be greater than extra heavy) and as short
as possible. Wafer type valves are not to be used for any connections to the vessel’s shell unless specially
approved. Lug type butterfly valves used as shell valves are to have a separate set of bolts on each end of the
valve so that the inboard end may be disconnected with the valve closed to maintain its watertight integrity.

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19.5 Materials
All shell fittings and valves required by 4-4-2/21 and 4-4-2/23 are to be of steel, bronze or other approved
ductile material. Valves of ordinary cast iron or similar material are not acceptable. The use of nodular
iron, also known as ductile iron or spheroidal-graphite iron, will be accepted, provided the material has an
elongation of not less than 12% in 50 mm (2 in.). All pipes to which this subsection refers are to be of steel
or other equivalent material, subject to special approval.

19.7 Shell Reinforcement

Overboard discharges are to have spigots extending through the shell plate and doubling plate, where
fitted, but need not project beyond the outside surface of the vessel.

19.9 Common Overboard Discharge

In general, various types of systems which discharge overboard are not to be interconnected without special
approval; that is, closed pumping systems, deck scuppers, gravity drains, etc. are not to have a common
overboard discharge.

21 Machinery and Pumping Systems

21.1 Valves Required (2006)

Positive closing valves are to be fitted at the shell in inlet and discharge piping. The controls are to be
readily accessible and are to be provided with indicators showing whether the valves are open or closed. In
order to be considered readily accessible, the controls, during normal operating conditions, are to be:
i) Located in a space normally entered without using tools,
ii) Clear of or protected from obstructions, moving equipment and hot surfaces that prevent operation
or servicing, and
iii) Within operator’s reach.
Materials readily rendered ineffective by heat are not to be used for connection to the shell where the
failure of the material in the event of a fire would give rise to danger of flooding.

21.3 Sea Chests

The locations of sea chests are to be such as to minimize the probability of blanking off the suction and
arranged so that the valves may be operated from the floors or gratings. Power-operated sea valves are to
be arranged for manual operation in the event of a failure of the power supply.
21.3.1 Strainer Plates
Sea chests are to be fitted with strainer plates at the vessel's side. The strainers are to have a clear
area of at least 1.5 times the area of the sea valves. Efficient means are to be provided for clearing
the strainers.
21.3.2 Ice Strengthening
For vessels with ice strengthening, see Part 6, Chapter 1 of the Steel Vessel Rules.

23 Scuppers and Drains

23.1 General (2007)

23.1.1 Application
These requirements apply to gravity drain systems from watertight and non-watertight spaces
located either above or below the freeboard deck.

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23.1.2 Definitions
23.1.2(a) Gravity drain system. A gravity drain system is a piping system in which flow is
accomplished solely by the difference between the height of the inlet end and the outlet end. For
the purposes of the Rules, gravity drain systems include those which discharge both inside and
outside the vessel.
23.1.2(b) Gravity discharge. A gravity discharge is an overboard drain from a watertight space
such as spaces below freeboard deck or within enclosed superstructures or deckhouses. Back-
flooding through a gravity discharge would affect the reserve buoyancy of the vessel.
23.1.2(c) Inboard end. The inboard end of an overboard gravity discharge pipe is that part of the
pipe at which the discharge originates. The inboard end to be considered for these requirements is
the lowest inboard end where water would enter the vessel if back-flooding would occur.
23.1.2(d) Scupper. A scupper is an overboard drain from a non-watertight space or deck area.
Back-flooding through a scupper would not affect the reserve buoyancy of the vessel.
23.1.3 Basic Principles
Enclosed watertight spaces (spaces below freeboard deck or within enclosed superstructures or
deckhouses) are to be provided with means of draining. This may be achieved by connection to
the bilge system or by gravity drains. In general, a gravity drain is permitted wherever the position
of the space allows liquid to be discharged by gravity through an appropriate opening in the
boundary of the space. Unless specifically stated (see 4-4-2/23.5.1(b) or the following paragraph),
the discharge can be directed overboard or inboard. Where directed overboard, means are to be
provided to prevent entry of sea water through the opening in accordance with 4-4-2/23.3. Where
directed inboard, suitable arrangements are to be provided to collect and dispose of the drainage.
Non-watertight spaces (open superstructures or deckhouses) and open decks, where liquid can
accumulate, are also to be provided with means of draining. In general, a gravity drain is permitted
for all non-watertight spaces. All such drains are to be directed overboard.
Gravity drains are to be capable of draining the space when the vessel is on even keel and either
upright or listed 5 degrees on either side.

23.3 Protection from Sea Water Entry (2007)

23.3.1 Overboard Gravity Discharges – Normally Open
Discharges led through the shell, either from spaces below the freeboard deck or from within
superstructures and deckhouses on the freeboard deck fitted with doors complying with the
requirements of 3-2-9/5, are to be fitted with efficient and accessible means for preventing water
from passing inboard.
Normally, each separate discharge is to have one automatic non-return valve with a positive means
of closing it from a position above the freeboard deck, except as below. Alternatively, one non-return
valve and one positive closing valve controlled from above the freeboard deck may be accepted.
Where the vertical distance from the summer loadline to the inboard end of the discharge pipe
exceeds 0.01L, the discharge may have two automatic non-return valves without positive means of
closing, provided that the inboard valve is always accessible for examination under service conditions.
The inboard valve is to be above the tropical load waterline. If this is not practicable, then,
provided a locally controlled stop valve is interposed between the two non-return valves, the
inboard valve need not be fitted above the tropical load waterline.
Where the vertical distance from the summer load waterline to the inboard end of the discharge
pipe exceeds 0.02L, a single automatic non-return valve without positive means of closing may be
accepted, provided it is located above the tropical load waterline (or, where assigned, timber tropical
load waterline). If this is impracticable, a locally operated positive closing valve may be provided
below the single non-return valve, in which case, the non-return valve need not be located above
the specified tropical load waterline.

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L is defined in 3-1-1/3. The means for operating the positive-action valve is to be readily accessible
and provided with an indicator showing whether the valve is open or closed. See 4-4-2/Figure 3.
Where sanitary discharges and scuppers lead overboard through the shell in way of machinery
spaces, the fitting to the shell of a locally operated positive closing valve, together with a non-return
valve inboard, will be acceptable.

FIGURE 3
Overboard Discharges – Valve Requirements (2005)

Remote Control
Freeboard Deck

Manned Machinery
0.02L Space

0.01L
TLWL TLWL

SLWL SLWL

- Screw down non-return valve - remotely operated

- Screw down non-return valve - locally operated
- Screw down stop valve
- Non-return valve
- Drain at inboard end of discharge line

23.3.2 Overboard Gravity Discharges – Normally Closed

For overboard discharges which are closed at sea, such as gravity drains from topside ballast tanks, a
single screw down valve operated from above the freeboard deck is acceptable.
23.3.3 Overboard Gravity Discharges from Spaces below the Freeboard Deck on Vessels Subject to
SOLAS Requirements
For vessels subject to SOLAS requirements, instead of the requirements identified in 4-4-2/23.3.1
above, each separate gravity discharge led through the shell plating from spaces below the freeboard
deck is to be provided with either one automatic non–return valve fitted with a positive means of
closing it from above the freeboard deck or with two automatic non–return valves without positive
means of closing, provided that the inboard valve is situated above the deepest subdivision load
line (DSLL) and is always accessible for examination under service conditions. Where a valve
with positive means of closing is fitted, the operating position above the freeboard deck shall
always be readily accessible and means shall be provided for indicating whether the valve is open
or closed.

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FIGURE 4
SOLAS Vessels – Overboard Discharges from Spaces below
Freeboard Deck – Valve Requirements (2007)

Remote Control
Freeboard Deck

DSLL
Manned Machinery
Space

- Screw down non-return valve - remotely operated

- Non-return valve
- Drain/scupper at inboard end of discharge line

23.3 .4 Scuppers and Discharges below the Freeboard Deck – Shell Penetration
Scuppers and discharge pipes originating at any level and penetrating the shell either more than
450 mm (17.5 in.) below the freeboard deck or less than 600 mm (23.5 in.) above the summer load
waterline are to be provided with a non-return valve at the shell. This valve, unless required above,
may be omitted if the length of piping up to the freeboard deck has a wall thickness at least equal
to the thickness of the shell plating or extra-heavy pipe, whichever is less.

23.5 Gravity Drains from Superstructures or Deckhouses

23.5.1 Enclosed Cargo Spaces (2007)
Drainage of enclosed cargo spaces situated on the bulkhead deck or the freeboard deck is to be
provided with the following:
23.5.1(a) Where the summer freeboard is such that the deck edge of the space being drained is
not immersed when the vessel heels five degrees, the drainage is to be by means of a sufficient number
of gravity drains of suitable size discharging directly overboard, in accordance with 4-4-2/23.3.
23.5.1(b) Where the summer freeboard is such that the deck edge of the space being drained is
immersed when the vessel heels five degrees, the drainage of the enclosed cargo spaces is to be led
to a suitable space, or spaces, of adequate capacity, having a high water level alarm and provided with
suitable arrangements for discharge overboard. In addition, the system is to be designed such that:
i) The number, size and disposition of the drain pipes are to prevent unreasonable accumulation
of free water;
ii) The pumping arrangements are to take into account the requirements for any fixed,
pressurized, water spraying, fire extinguishing system;
iii) Water contaminated with oil or other dangerous substances is not drained to machinery
spaces or other spaces where sources of ignition may be present; and
iv) Where the enclosed cargo space is protected by a fixed gas fire extinguishing system, the
drain pipes are fitted with means to prevent the escape of the smothering gas.

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23.5.2 Open Superstructures and Deckhouses

Scuppers leading from superstructures or deckhouses not fitted with doors complying with the
requirements of 3-2-9/5 are to be led overboard.

23.7 Vessels Receiving Subdivision Loadlines

For vessels receiving subdivision loadlines, the bulkhead deck is to apply to provisions given in 4-4-2/23.3
when it is higher than the freeboard deck.

25 Cooler Installations External to the Hull

25.1 General
The inlet and discharge connections of external cooler installations are to be in accordance with 4-4-2/19.1
through 4-4-2/19.5 and 4-4-2/21.1, except that wafer type valves will be acceptable.

25.3 Integral Keel Cooler Installations

The positive closing valves required by 4-4-2/25.1 need not be provided if the keel (skin) cooler installation
is integral with the hull. To be considered integral with the hull, the installation is to be constructed such
that channels are welded to the hull with the hull structure forming part of the channel, the channel material is
to be at least the same thickness and quality as that required for the hull and the forward end of the cooler
is to be faired to the hull with a slope of not greater than 4 to 1.
If positive closing valves are not required at the shell, all flexible hoses or joints are to be positioned above
the deepest load waterline or be provided with an isolation valve.

25.5 Non-integral Keel Cooler Installations (2006)

Where non-integral keel coolers are used, if the shell penetrations are not fully welded, the penetration is to
be encased in a watertight enclosure.
Non-integral keel coolers are to be suitably protected against damage from debris and grounding by
recessing the unit into the hull or by the placement of protective guards.

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PART Section 3: Bilge and Ballast Systems and Tanks

4
CHAPTER 4 Pumps and Piping Systems

SECTION 3 Bilge and Ballast Systems and Tanks

1 General Arrangement of Bilge Systems (2011)

A pumping system is to be provided in all vessels capable of pumping from and draining any compartment
when the vessel is on an even keel and either upright or listed five degrees. For this purpose, wing suctions
will often be necessary, except in narrow compartments at the ends of the vessel. Arrangements are to be made
whereby water in the compartment will drain to the suction pipes. Efficient means are to be provided for
draining water from all tank tops and other watertight flats. Peak tanks and comparatively small compartments,
such as chain lockers, echo sounder spaces, and decks over peak tanks, etc., may be drained by ejectors or
hand pumps. Where ejectors are used for this purpose, the overboard discharge arrangements are to comply
with 4-4-2/23.

3 Bilge Pumps

3.1 Number of Pumps

All self-propelled vessels 20 m (65 ft) in length or greater are to be provided with two power driven bilge
pumps, one of which may be attached to the propulsion unit. Vessels under 20 m (65 ft) in length are to be
provided with one fixed power driven pump, which may be an attached unit, and one portable hand pump.

3.3 Capacity
The capacity of each pump is to be in accordance with the following:

Vessel Length Minimum Capacity per Pump

Below 20 m (65 ft) 5.5 m3/hr (25 gpm)
(hand pump 5 gpm, 1.13 m3/hr)
20 m (65 ft) or greater but below 30.5 m (100 ft) 11.36 m3/hr (50 gpm)
30.5 m (100 ft) or greater but below 45.7 m (150 ft) 14.33 m3/hr (66.6 gpm)
45.7 m (150 ft) and greater Q = 5.66d2/103 m3/hr
Q = 16.1d2 gpm

Q = pump capacity
d = required diameter of main bilge line suction, mm (in.). See 4-4-3/5.9.
When more than two pumps are connected to the bilge system, their arrangement and aggregate capacity
are not to be less effective.

3.5 Centrifugal Pumps

Where centrifugal pumps are installed, suitable means for priming are to be provided.

3.7 Independent Power Bilge Pumps

Sanitary, ballast and general service pumps may be accepted as independent power bilge pumps, provided
they are of the required capacity and are fitted with the necessary control valves required by 4-4-3/5.1 for
pumping bilges.

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5 Bilge and Ballast Piping

5.1 General
The arrangement of the bilge and ballast pumping systems is to be such as to prevent the possibility of
water or oil passing into the cargo and machinery spaces, or from one compartment to another, whether
from the sea, water ballast or oil tanks. The bilge and ballast mains are to have separate control valves at
the pumps.

5.3 Installation
Bilge or ballast pipes, where permitted to pass through compartments intended for the carriage of oil, are to
be of either steel or wrought iron.
Where bilge pipes in way of deep tanks are not led through a watertight or oil-tight tunnel, the bilge lines
are to be of steel and extra heavy. Similarly, where ballast pipes in way of deep tanks other than ballast
tanks are not led through a watertight or oil-tight tunnel, the ballast lines are to be of steel and extra heavy.
For both bilge and ballast piping, the number of joints is to be kept to a minimum and to be arc welded or
extra heavy flanged. The piping within a deep tank is to be installed to take care of expansion. A non-
return valve is to be fitted at the open end of bilge pipes.

5.5 Manifolds, Cocks and Valves

5.5.1 General
All manifolds, cocks and valves in connection with the bilge pumping arrangement are to be in
positions which are accessible at all times under ordinary circumstances. All valves in the machinery
space controlling the bilge suctions from the various compartments are to be of the stop-check
type. If valves are fitted at the open ends of pipes, they are to be of the non-return type.
5.5.2 Common-main-type Bilge Systems (2005)
A common-main bilge system normally consists of one or more main lines installed along the
length of the vessel fitted with branch bilge suction connections to various compartments. Where
only one fore-and-aft bilge main is installed, the bilge main is to be located inboard of 20% of the
molded beam of the vessel, measured inboard from the side of the ship perpendicular to the
centerline at the level of the summer load line. If there is at least one bilge main on each side of
the vessel, then those bilge mains may be installed within 20% of the molded beam, measured
inboard from the side of the ship perpendicular to the centerline at the level of the summer load
line, provided they are fitted with branch lines and control valves arranged such that it is possible
to effectively pump out each compartment using the main(s) on either side of the vessel.
For all common-main-type bilge systems, the control valves required in the branches from the
bilge main are to be accessible at all times and are to be of the stop-check type with an approved
type of remote operator. Remote operators may be located in a manned machinery space, or from
an accessible position above the freeboard deck or from underdeck walkways. Remote operators
may be of the hydraulic, pneumatic, electric or reach-rod type.
5.5.3 Controls for Ballast Tank Valves
Ballast tank valves are to be arranged so they will remain closed at all times, except when ballasting.
For this purpose, manual screw thread operated valves, positive holding arrangements for butterfly
type valves or other equivalent arrangements may be used. Where installed, remote controlled
valves are to be arranged so they will close and remain closed upon loss of control power, or will
remain in their last position and are provided with a readily accessible manual means of operation
in case of loss of power to the valve control system. Remote control of bilge and ballast valves is
to be clearly marked at the control station and means are to be provided to indicate whether the
valve is open or closed.

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5.7 Strainers (2005)

Bilge lines in machinery spaces other than emergency suctions are to be fitted with strainers easily accessible
from the floor plates and are to have straight tail pipes to the bilges. The ends of bilge lines in other
compartments are to be fitted with suitable strainers having an open area of not less than three times the
area of the suction pipe.

5.9 Size of Bilge Suctions

The least internal diameter of bilge suction pipes is to be that of the nearest commercial size within 6 mm
(0.25 in.) of the diameter determined by the following equations:
5.9.1 Main Line
For the diameter of main bilge line suctions and direct bilge suctions to the pumps:

d = 25 + 1.68 L( B + D) mm d=1+ L( B + D) / 2500 in.

5.9.2 Branch Lines

For the equivalent diameter of the combined branch suctions to a compartment:

d = 25 + 2.16 c( B + D) mm d=1+ c( B + D) / 1500 in.

where
d = internal diameter of pipe, in mm (in)
L = length of vessel, as defined in 3-1-1/3, in m (ft)
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
c = length of compartment, in m (ft)
D = molded depth to bulkhead or freeboard deck, in m (ft), except that for the
main line in a vessel having an enclosed cargo space on the bulkhead or
freeboard deck which is internally drained in accordance with 4-4-2/23.5.1(b)
and which extends for the full length of the vessel, D is to be measured to the
next deck above the bulkhead or freeboard deck. Where the enclosed cargo
spaces cover a lesser length, D is to be taken as a molded depth to the
bulkhead or freeboard deck plus lh/L, where l and h are aggregate length
and height, respectively, of the enclosed cargo spaces.
5.9.3 Main Line Reduction
Where engine room bilge pumps are fitted primarily for drainage within the engine room, L may
be reduced by the combined length of the cargo tanks or cargo holds. In such cases, the cross
sectional area of the bilge main is not to be less than twice the required cross sectional area of the
engine room branch lines.
5.9.4 Alternate Size Requirements
For vessels below 30.5 m (100 ft) in length, the bilge pipe sizes may be in accordance with the
following in lieu of 4-4-3/5.9.1.

Vessel Length Minimum Pipe Size (I.D.)

Below 20 m (65 ft) 25 mm (1 in.)
20 m (65 ft) or greater but 38 mm (1.5 in.)
below 30.5 m (100 ft)
5.9.5 Size Limits
For vessels of 30.5 m (100 ft) in length or greater, no main suction piping is to be less than 63 mm
(2.5 in.) internal diameter. No branch piping need be more than 100 mm (4 in.) I.D., nor is it to be
less than 50 mm (2 in.) I.D., except that for drainage of small pockets or spaces 38 mm (1.5 in.)
I.D. pipe may be used.

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5.9.6 Bilge Common-main (2005)

The diameter of each common-main bilge line may be determined by the equation for bilge branches
given in 4-4-3/5.9.2 using the combined compartment length upstream of the point where the
diameter is being determined. In case of double hull construction with full depth wing tanks served by
a ballast system, where the beam of the vessel is not representative of the breadth of the compartment,
B may be appropriately modified to the breath of the compartment. However, no common-main
bilge pipe needs to be more than the diameter for the bilge main given in 4-4-3/5.9.1.

5.11 Gravity Drains

Gravity drains that penetrate the main machinery space watertight bulkheads below the freeboard deck and
terminate within the main machinery space are to be fitted with a valve operable from above the freeboard
deck or with quick-acting, self-closing valves. The valve should preferably be located in the main machinery
space. When gravity drains from other spaces are terminated in cargo holds, the cargo hold bilge well is to
be fitted with a high level alarm. Gravity drains which terminate in spaces which are protected by fixed gas
extinguishing systems are to be fitted with means to prevent the escape of extinguishing medium.

7 Direct and Emergency Bilge Suctions for Main Machinery Spaces

(2011)

7.1 Direct Bilge Suction

For vessels 20 m (65 ft) in length and greater, one of the independently driven bilge pumps (see 4-4-3/3.1)
is to be fitted with a suction led directly from the main machinery space bilge to the suction valve chest of
the pump and arranged so that it can be operated independently of the bilge system. The size of this line is
to be such that the pump will deliver its full capacity. The direct bilge suction is to be controlled by a stop-
check valve.
If watertight bulkheads separate the main machinery space into compartments, a direct suction is to be
fitted to each compartment unless the pumps available for bilge service are distributed throughout these
compartments. At least one pump in each such compartment is to be fitted with a direct suction for its
compartment.

7.3 Emergency Bilge Suctions

In addition to the direct bilge suction in 4-4-3/7.1, an emergency bilge suction is to be fitted for the main
machinery spaces on all oceangoing vessels 55 m (180 ft) in length and over. The emergency bilge suction
is to be led straight to the largest independently driven pump in the main machinery space, other than the
required bilge pumps. Where this pump is not suitable, the second largest suitable pump in the main
machinery space may be used for this service, provided that the selected pump is not one of the required
bilge pumps and its capacity is not less than that of the required bilge pump.
The area of the emergency bilge suction pipe is to be equal to the full suction inlet of the pump selected.
The emergency bilge line is to be provided with a suction stop-check valve, which is to be so located as to
enable rapid operation, and a suitable overboard discharge line. The hand wheel of emergency bilge suction
valve is to be position not less than 460 mm (18 in.) above the floor plates.

9 Vent Pipes

9.1 General (2011)

Except for comparatively small compartments that are not fitted with a fixed means of drainage, vent pipes
are to be fitted to all tanks, cofferdams, voids, tunnels and compartments which are not fitted with other
ventilation arrangements. In all vessels, the structural arrangement in double- bottom and other tanks is to
be such as to permit the free passage of air and gases from all parts of the tanks to the vent pipes. Each tank
is to be fitted with at least one vent pipe which is to be located at the highest part of the tank. Vent pipes
are to be arranged to provide adequate drainage under normal conditions. No shutoff valve or closing
device that can prevent the venting from a tank is to be installed in vent piping.

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9.3 Height and Wall Thickness (2010)

9.3.1 Vents Exposed to Weather
Vent pipes on decks exposed to the weather are to have the following heights:
i) 760 mm (30 in.) for those on the freeboard deck; and
ii) 450 mm (17.5 in.) for those on the superstructure deck.
The height is to be measured from the deck to the point where water may have access below.
Where these heights may interfere with the working of the vessel, a lower height may be accepted,
provided that ABS is satisfied that the closing arrangements and other circumstances justify a lower
height.
The wall thicknesses of vent pipes where exposed to the weather are to be not less than that specified
below. For vent pipes located on the fore deck, as defined in 3-2-14/11.7.1, the strength and wall
thickness requirements are to also comply with 3-2-14/11.7.2 and 3-2-14/11.7.3:

Nominal Size, d Min. Wall Thickness

d ≤ 65 mm (2.5 in.) 6.0 mm (0.24 in.)
65 mm (2.5 in.) < d < 150 mm (6 in.) by interpolation (1)
d ≥ 150 mm (6 in.) 8.5 mm (0.33 in.)
Note:
1 6 + 0.029(d – 65) mm or 0.24 + 0.026(d – 2.5) in.

9.3.2 Vents not Exposed to Weather

Vent pipes not exposed to the weather need not comply with the height and wall thickness required
by 4-4-3/9.3.1.

9.5 Size
Vent pipes are to have a minimum internal diameter not less than 38 mm (1.5 in.) and not less than the
internal diameter of the fill line. Where tanks are to be filled by pump pressure, the aggregate area of the
vents in the tank is to be at least 125% of the effective area of the filling line, except that when overflows
are fitted, the area of the overflow is to be at least 125% of the effective area of the filling line and the
vents need not exceed the above minimum size. For vessels with length, L, (as defined in 3-1-1/3.1) between
80 meters (263 feet) and 90 meters (295 feet), the minimum diameter of vent pipes on the fore deck is not
to be less than 65 mm [see 3-2-14/11.7.3(b)].
Notwithstanding the above, the pump capacity and pressure head are to be considered in the sizing of vents
and overflows. When high capacity and/or high head pumps are used, calculations demonstrating the adequacy
of the vent and overflows are to be submitted.

9.7 Location (1 July 1998)

Vents for compartments required for subdivision (such as double bottom or wing spaces) are to be led above
the freeboard or bulkhead deck. In addition, vents for ballast tanks, fuel oil tanks, cargo tanks, thermal oil
tanks and those cofferdams adjacent to cargo oil tanks are to be led to the weather. Vents for other tanks
may terminate within the machinery space, provided that the open ends are situated to prevent the possibility
of overflowing on electric equipment, engines or heated surfaces.
For vessels of 500 gross tons and above, vent pipes for fuel oil service tanks, fuel oil settling tanks and
lubricating oil tanks which directly serve the engines are to be located and arranged and/or suitably
protected from mechanical damage in order to minimize the possibility of being broken and allowing the
ingress of seawater splashes or rainwater into the above mentioned tanks.

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9.9 Vent Outlets

All vent and overflow pipes on the open deck are to terminate by way of return bends.
9.9.1 Fuel Oil Tank Vents (2007)
Vent outlets from fuel oil tanks are to be fitted with corrosion-resistant flame screens having a
clear area through the mesh of not less than the required area of the vent pipe. Either a single
screen of corrosion-resistant wire of at least 12 by 12 meshes per lineal cm (30 by 30 mesh per
lineal inch ), or two screens of at least 8 by 8 meshes per lineal cm (20 by 20 mesh per lineal inch)
spaced not less than 13 mm (0.5 inch) nor more than 38 mm (1.5 inch) apart are acceptable.
Note: Mash count is defined as a number of openings in a lineal cm (inch) counted from the center of any wire
to the center of a parallel wire.

9.9.2 Vent Closure (2010)

All vents terminating in the weather are to be fitted with return bends (gooseneck), or equivalent,
and the vent outlet is to be provided with an automatic means of closure type i.e., close automatically
upon submergence (e.g., ball float or equivalent), complying with 4-4-3/9.9.3.
9.9.3 Vent Outlet Closing Devices (2008)
9.9.3(a) General. Where vent outlets required by 4-4-3/9.9.2 are to be fitted with automatic closing
devices, they are to comply with the following:
9.9.3(b) Design.
i) Vent outlet automatic closing devices are to be so designed that they will withstand both
ambient and working conditions, and be suitable for use at inclinations up to and including
±40°.
ii) Vent outlet automatic closing devices are to be constructed to allow inspection of the closure
and the inside of the casing as well as changing the seals.
iii) Efficient ball or float seating arrangements are to be provided for the closures. Bars, cage
or other devices are to be provided to prevent the ball or float from contacting the inner
chamber in its normal state and made in such a way that the ball or float is not damaged
when subjected to water impact due to a tank being overfilled.
iv) Vent outlet automatic closing devices are to be self-draining.
v) The clear area through a vent outlet closing device in the open position is to be at least
equal to the area of the inlet.
vi) An automatic closing device is to:
• Prevent the free entry of water into the tanks,
• Allow the passage of air or liquid to prevent excessive pressure or vacuum developing
in the tank.
vii) In the case of vent outlet closing devices of the float type, suitable guides are to be
provided to ensure unobstructed operation under all working conditions of heel and trim.
viii) The maximum allowable tolerances for wall thickness of floats should not exceed ±10%
of thickness.
ix) The inner and outer chambers of an automatic air pipe head is to be of a minimum thickness
of 6 mm (0.24 inch).
9.9.3(c) Materials.
i) Casings of vent outlet closing devices are to be of approved metallic materials adequately
protected against corrosion.
ii) For galvanized steel air pipe heads, the zinc coating is to be applied by the hot method
and the thickness is to be 70 to 100 micrometers (2.756 to 3.937 mil).

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iii) For areas of the head susceptible to erosion (e.g., those parts directly subjected to ballast
water impact when the tank is being pressed up, for example the inner chamber area above
the air pipe, plus an overlap of 10° or more to either side) an additional harder coating
should be applied. This is to be an aluminum bearing epoxy, or other equivalent coating,
applied over the zinc.
iv) Closures and seats made of non-metallic materials are to be compatible with the media
intended to be carried in the tank and to seawater, and suitable for operating at ambient
temperatures between –25°C and 85°C (–13°F and 185°F).
9.9.3(d) Type Testing.
i) Testing of Vent Outlet Automatic Closing Devices. Each type and size of vent outlet
automatic closing device is to be surveyed and type tested at the manufacturer's works or
other acceptable location.
The minimum test requirements for a vent outlet automatic closing device are to include the
determination of the flow characteristics of the vent outlet closing device, the measurement
of the pressure drop versus the rate of volume flow using water and with any intended
flame or insect screens in place and also tightness tests during immersion/emerging in
water, whereby the automatic closing device is to be subjected to a series of tightness tests
involving not less than two (2) immersion cycles under each of the following conditions:
• The automatic closing device is to be submerged slightly below the water surface at a
velocity of approximately 4 m/min. (13.12 ft/min) and then returned to the original
position immediately. The quantity of leakage is to be recorded.
• The automatic closing device is to be submerged to a point slightly below the surface
of the water. The submerging velocity is to be approximately 8 m/min and the air
pipe vent head is to remain submerged for not less than 5 minutes. The quantity of
leakage is to be recorded.
• Each of the above tightness tests are to be carried out in the normal position as well
as at an inclination of 40 degrees.
The maximum allowable leakage per cycle is not to exceed 2 ml/mm (1.312 × 10-2 gal/inch)
of nominal diameter of inlet pipe during any individual test.
ii) Testing of Non-Metallic Floats. Impact and compression loading tests are to be carried
out on the floats before and after pre-conditioning as follows:

Test Temperature °C (°F): –25°C (–13°F) 20°C (68°F) 85°C (185°F)

Test Conditions
Dry Yes Yes Yes
After immersing in water Yes Yes Yes
After immersing in fuel oil NA Yes NA

Immersing in water and fuel oil is to be for at least 48 hours.

a) Impact Test. The test may be conducted on a pendulum type testing machine.
The floats are to be subjected to 5 impacts of 2.5 N-m (1.844 lbf-ft) each and are
not to suffer permanent deformation, cracking or surface deterioration at this impact
loading.
Subsequently the floats are to be subjected to 5 impacts of 25 N-m (18.44 lbf-ft)
each. At this impact energy level some localized surface damage at the impact
point may occur. No permanent deformation or cracking of the floats is to appear.

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b) Compression Loading Test. Compression tests are to be conducted with the

floats mounted on a supporting ring of a diameter and bearing area corresponding
to those of the float seating with which it is intended that float shall be used. For
ball type float, loads are to be applied through a concave cap of the same internal
radius as the test float and bearing on an area of the same diameter as the seating.
For a disc type float, loads are to be applied through a disc of equal diameter as
the float.
A load of 3430 N (350 kgf, 770 lbf) is to be applied over one minute and maintained
for 60 minutes. The deflection is to be measured at intervals of 10 minutes after
attachment of the full load.
The record of deflection against time is to show no continuing increase in
deflection and, after release of the load, there is to be no permanent deflection.
iii) Testing of Metallic Floats. The above described impact tests are to be carried out at room
temperature and in the dry condition.

11 Overflow Pipes (1998)

11.1 General Requirements

Overflow pipes discharging through the vessel’s side are to be located as far above the deepest load line as
practicable and are to be provided with nonreturn valves located on the vessel’s side. Where the overflow
does not extend above the freeboard deck, there is to be provided, in addition, an efficient and accessible
means for preventing water from passing inboard. Such means may consist of another nonreturn valve
located in an accessible position above the deepest load line.
Where it is impracticable to locate the inner valve in an accessible position, one nonreturn valve with
positive means for closing from an accessible position above the freeboard or bulkhead deck will be
acceptable, provided there are suitable arrangements to insure the valve not being closed by unauthorized
persons and provided a notice is posted in a conspicuous place at the operating station to the effect that the
valve is never to be closed, except as may be required in an emergency.

11.3 Overflows from Combustible and Flammable Liquid Tanks (2010)

Overflow pipes from combustible and flammable liquid tanks are to be led to an overflow tank or to a
storage tank with sufficient excess capacity (normally 10 minutes at transfer pump capacity) to accommodate
the overflow. An alarm device is to be provided to give warning when the liquid reaches a predetermined
level in the overflow tank. If a sight flow glass is also provided in the overflow pipe, then such sight
glasses are to be fitted only in vertical sections of overflow pipes and be in readily visible positions.

11.5 Overflow Common Header

Where overflows from the tanks in more than one watertight subdivision are connected to a common
header below the freeboard or bulkhead deck, the arrangement is to be such as to prevent fore-and-aft
flooding of one watertight bulkhead subdivision from another in the event of damage.

13 Sounding

13.1 General
All tanks are to be fitted with a suitable means of determining the level of the liquid therein. Such means
may be sounding pipes, gauge glasses or other approved level indicating systems or devices.
All compartments, including cofferdams and pipe tunnels, which are not readily accessible are to be fitted
with sounding pipes if the compartment is adjacent to the sea or has pipes carrying liquids passing through it.

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13.3 Sounding Pipes

Sounding pipes are not to be less than 38 mm (1.5 in.) inside diameter. They are to be led as straight as
possible from the lowest part of the tank or compartment to the bulkhead deck or to a position which is
always accessible. If sounding pipes terminate below the freeboard deck, they are to be provided with means
for closing in the following manner:
13.3.1 Oil Tanks
Quick-acting, self-closing gate valves are required.
13.3.2 Other Tanks
A screw cap secured to the pipe with a chain or a gate valve is required.
Provision is to be made to prevent damaging the vessel’s plating by the striking of the sounding
rod. In general, sounding pipes are not to pass through bilge wells, but if this is not practicable, the
pipe is to be at least extra-heavy in the bilge well. Sounding pipes for combustible or flammable
fluids are not to terminate in accommodation spaces.
13.3.3 Ignition of Spillage
13.3.3(a) Fuel Oil Tanks. Sounding pipes for fuel oil tanks are not to terminate in any space
where the risk of ignition of spillage may exist. In particular, they are not to terminate in machinery
spaces or in close proximity to internal combustion engines, generators, electric equipment or surfaces
with temperatures in excess of 220°C (428°F) in other spaces. Where it is impracticable to do
otherwise, sounding pipes from fuel oil tanks may terminate in machinery spaces, provided the
following are met:
i) The sounding pipes terminate in locations remote from ignition hazards or effective
precautions such as shielding are taken to prevent fuel oil spillage from coming into contact
with a source of ignition; and
ii) The terminations of sounding pipes are fitted with quick-acting, self-closing gate valves
and with a small diameter self-closing test cock or equivalent located below the gate valve,
provided for the purpose of ascertaining that fuel oil is not present in the sounding pipe
before the gate valve is opened. Provisions are to be made so as to prevent spillage of fuel
oil through the test cock from creating an ignition hazard; and
iii) (2005) An approved level gauge is provided. However, short sounding pipes may be used
for oil tanks other than double bottom tanks without the additional closed level gauge,
provided an overflow system is fitted, see 4-4-3/11. The oil level gauge may also be omitted
for vessels less than 500 gross tons.
13.3.3(b) Lubricating Oil Tanks (2005).Sounding pipes from lubricating oil tanks may terminate
in machinery spaces provided that the following are met:
i) The sounding pipes are to terminate in locations remote from the ignition hazards, or
effective precautions, such as shielding, are taken to prevent oil spillage from coming into
contact with a source of ignition.
ii) The termination of sounding pipes is fitted with a quick-acting self-closing gate valve.
Alternatively, for lubricating oil tanks that cannot be filled by a pump, the sounding pipes
may be fitted with an appropriate means of closure such as a shut-off valve or a screw cap
attached by chain to the pipe.

13.5 Gauge Glasses (2006)

Tanks may be fitted with gauge glasses, provided the gauge glasses are fitted with a valve at each end and
adequately protected from mechanical damage.
Gauge glasses for tanks containing flammable or combustible liquids are to be of the flat glass type having
approved self-closing valves at each end. For hydraulic oil tanks located in spaces other than category A
machinery spaces, cylindrical gauge glasses with approved self closing valves at each end will be acceptable,
provided such spaces do not contain internal combustion engines, generators, major electrical equipment or
piping having a surface temperature in excess of 220°C (428°F).

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Gauge glasses for tanks integral with the shell which are located below the deepest load waterline are to be
of the flat glass type and have approved self-closing valves at each end.
Isolation valves are to be fitted to allow for gauges removal without emptying the tank, see 4-4-1/9.17.3.

13.7 Level Indicating Systems and Devices (2005)

Where a level indicating device or system is provided for determining the level in a tank containing
flammable or combustible liquid, failure of the device/system is not to result in the release of the contents
of the tank through the device. Level switches, which penetrate below the tank top, may be used, provided
they are contained in a steel enclosure or other enclosures not being capable of being destroyed by fire. If
an overflow is not fitted, means are also to be provided to prevent overfilling of the tank in the event of
malfunction of the indicating device/system.

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PART Section 4: Fuel Oil and Lubricating Oil Systems and Tanks

4
CHAPTER 4 Pumps and Piping Systems

SECTION 4 Fuel Oil and Lubricating Oil Systems and Tanks

1 Fuel Oil Piping Systems

1.1 General Arrangement

1.1.1 Tanks (2011)
1.1.1(a) Structural Tanks As far as practicable, fuel oil tanks are to be part of the vessel’s structure
and located outside of Category A machinery spaces. Where fuel oil tanks, other than double bottom
tanks, are necessarily located adjacent to or within a Category A machinery space, the arrangements
are to reduce the area of the tank boundary common with the machinery space of category A to a
minimum, and to comply with the following:
i) Fuel tanks having boundaries common with machinery spaces of category A are not to
contain fuel oils having a flash point of 60°C (140°F) or less.
ii) At least one of their vertical sides is to be contiguous to the machinery space boundaries.
The arrangements in 4-4-4/Figure 1 are acceptable for structural tanks provided the
requirements of 4-4-4/11 are complied with. (The side shell is not being included in
contiguous boundary of the category A machinery space.)
iii) The bottom of the fuel oil tank is not to be so exposed that it will be in direct contact with
flame should there be a fire in a Category A machinery space. The fuel tank is to extend
to the double bottom. Alternatively, the bottom of the fuel oil tank is to be fitted with a
cofferdam. The cofferdam is to be fitted with suitable drainage arrangements to prevent
accumulation of oil in the event of oil leakage from the tank.

FIGURE 1
Acceptable Fuel Oil Tanks Arrangements Inside Category A Machinery Spaces (2011)
A
Cofferdam

Cofferdam
F.O.T
≤ 30 m3 Side Shell

F.O.T F.O.T
Machinery Machinery
Aft. Bhd
Space Space
(Category A) (Category A)

Fwd. Bhd

F.O.T
Void
Double Bottom

A Section A-A

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1.1.1(b) Free Standing Tanks In general, the use of free standing fuel oil tanks is to be avoided.
Where permitted, they are to be placed in an oil tight spill tray of ample size with adequate means
of drainage in accordance with 4-4-1/9.23.
1.1.2 Spillage (2011)
No fuel oil tank is to be situated where spillage or leakage therefrom can constitute a hazard by
falling on heated surfaces or electrical equipment. Precautions are to be taken to prevent any oil
that may escape under pressure during inspection or maintenance of any pump, filter or heater
from coming into contact with a source of ignition as defined in 4-1-1/13.17.
To prevent the ignition of fuel oil, all hot surfaces likely to reach a temperature above 220°C
(428°F) during service are to be insulated with non-combustible, and preferably non oil-absorbent
materials. Such insulation materials, if not impervious to oil, are to be encased in oil-tight steel
sheathing or equivalent. The insulation assembly is to be well-installed and supported having
regard to its possible deterioration due to vibration.
1.1.3 Service and Settling Tanks (2004)
Vessels of 500 gross tonnage and above with the keel laid or in similar stage of construction on or
after 1 July 1998 are to meet the following requirements of i), ii), and iii)
i) The vent pipes for fuel oil service and settling tanks which directly serve the engines are
to be located and arranged and/or suitably protected from mechanical damage in order to
minimize the possibility of being broken and allowing the ingress of seawater splashes or
rainwater into the above mentioned tanks. At least two fuel oil service tanks are to be
provided and the capacity with one service tank unavailable is to be sufficient for at least
eight hours operation of the propulsion plant at maximum continuous rating and the
generator plant (excluding emergency generator) at the normal sea load.
ii) Where the propulsion plant and auxiliary machinery are supplied by different service
tanks or where more than one type of fuel is used onboard the vessel, the number and
capacity of the fuel oil service tanks is to be sufficient such that the propulsion plant,
including all auxiliary machinery vital for propulsion, and the generator plant have both a
main fuel oil supply and a back-up fuel oil supply. The capacity of the tanks with one
service tank unavailable is to be sufficient to provide the machinery it serves with enough
fuel oil for at least eight hours operation, as required above.
iii) Alternatives equivalent to the above arrangements will be considered.
A service tank is a fuel tank which contains only fuel of a quality ready for use, that is, fuel of a
grade and quality that meets the specification required by the equipment manufacturer. A service
tank is to be declared as such and is not to be used for any other purpose.

1.3 Piping, Valves and Fittings

Fuel oil pipes, valves and fittings are to be of steel or other approved materials.

1.5 Oil Heating Arrangements

1.5.1 Oil Heaters
Where heaters are provided in fuel oil systems, they are to be fitted with a temperature control and
either a high temperature alarm or a low flow alarm, except where the maximum temperature of
the heating medium does not exceed 220°C (428°F).
Where electric heaters are fitted, they are to be arranged to de-energize automatically when the oil
level falls to a predetermined height to ensure that the heating elements are permanently submerged
during operation. In addition, a safety temperature switch with a manual reset independent from
the automatic control sensor is to be provided to cut off the electric power supply in order to avoid
a surface temperature of 220°C (428°F) or above.

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1.5.2 Tanks
Unless specially approved otherwise, fuel oil in storage tanks is not to be heated to temperatures
within 10°C (18°F) below flash point of the fuel oil.
Where heating arrangements are provided for settling and service tanks, the control and alarm
requirements of 4-4-4/1.5.1 are applicable.

1.7 Multiple Internal Combustion Engine Installations (1 July 2002)

In multi-engine propulsion installations on vessels 500 gross tons and above, which are supplied from the
same fuel source, means of isolating the fuel supply and spill (return) piping to individual engines is to be
provided. The means of isolation is not to affect the operation of the other engines and is to be operable
from a position not rendered inaccessible by a fire on any of the engines.
Similarly, for multi-engine auxiliary diesel installations on vessels 500 gross tons and above, the same
requirements are applicable.

1.9 Overflows from Combustible and Flammable Liquid Tanks (2010)

For overflow pipes from combustible and flammable liquid tanks, see 4-4-3/11.3.

3 Fuel Oil Transfer and Filling

3.1 General
Where fuel oil transfer arrangements are furnished, two transfer pumps are to be provided and one of them
is to be independent of the main engine. The fuel oil pumping arrangements are to be distinct from the
other pumping systems as far as practicable, and the means provided for preventing dangerous interconnection
in service are to be thoroughly effective.

3.3 Pipes in Oil Tanks

Oil pipes and other pipes, where passing through oil tanks, are to be of wrought iron or steel, except that
other materials may be considered where it is demonstrated that the material is suitable for the intended
service. All packing is to be of a composition not affected by oil.

3.5 Control Valves or Cocks

Valves or cocks controlling the various suctions are to be located close to the bulkhead where the suctions
enter the machinery spaces and, wherever practicable, directly over the gutterway in way of deep and settling
tanks. Pumps, strainers, etc., requiring occasional examination are to have drip pans.

3.7 Valves on Oil Tanks (2004)

Where pipe lines emanate from fuel oil tanks at such a level that they will be subjected to a static head of
oil from the tank, they are to be fitted with positive closing valves located at the tank. Where the fuel oil
piping passes through adjacent tanks, the valve required above may be located where the pipe run exits the
adjacent tank(s), provided the piping in the adjacent tanks is extra-heavy and has all welded connections.
However, if the adjacent tank is a fuel oil tank, the pipe run within the fuel oil tank is to be at least standard
thickness.
If the valves are installed on the outside of the tank, they are not to be of cast iron. The use of nodular iron,
also known as ductile iron or spheroidal-graphite iron, may be used, provided the material has an elongation
not less than 12% in 50 mm (2 in.). Arrangements are to be provided for closing them at the valve and for
tanks having a capacity of 500 liters (132 US gal.) or greater, from a readily accessible and safe location
outside of the compartment in which the valve is located.
If the positive closing valve required above is situated in a shaft tunnel or pipe tunnel or similar space,
arrangements for closing may be effected by means of an additional valve on the pipe or pipes outside of
the tunnel or similar space. If such an additional valve is fitted in the machinery space, it is to be operated
from a position outside of this space.

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If the valves are located inside of the tank, they may be of cast iron and arranged for remote control only,
but additional valves for local control are to be located in the machinery space.
Where independent filling lines are fitted, they are to enter at or near the top of the tank, but if this is
impracticable, they are to be fitted with non-return valves at the tank.
The valves required above may be remotely operated by reach rods or by electric, hydraulic or pneumatic
means. The source of power to operate these valves is to be located outside of the space in which the
valves are located. The positioning of the valve by either local or remote means is not to interfere with the
ability of the other means to close the valve. This remote means of closure is to override all other means of
valve control. The use of an electric, hydraulic or pneumatic system is not acceptable to directly keep the
valve in the open position.
Materials readily rendered ineffective by heat are not to be used in the construction of the valves or the
closure mechanism, unless adequately protected to ensure effective closure facility in the event of fire. If
electric cables are utilized, they are to be fire-resistant, meeting the requirements of IEC 60331. Hydraulic
systems are to be in accordance with 4-4-6/1 for both Class I and II piping systems. For a pneumatic
system, the air supply may be from a source from within the space, provided a separate receiver complying
with the following is located outside of the space:
i) Sufficient capacity to close all connected valves twice.
ii) Fitted with low air pressure alarm.
iii) Air supply line is fitted with a non-return valve adjacent to the receiver.

3.9 Remote Shutdown of Pumps

Machinery driving fuel oil transfer pumps, oil fuel unit pumps and other similar fuel pumps are to be fitted
with remote shutdowns complying with 4-5-1/5.3.

3.11 Oil Drain Tanks

Drain tanks, where fitted, for waste oil, fuel oil overflows, drains, all oil drip pans, fuel injection piping, etc.,
are to have air and sounding pipes. Non-return valves are to be fitted in drain lines entering the drain tanks,
except where backflow would not present a hazard. Suitable means are to be provided for pumping out
these drain tanks.
Oil tanks not forming a part of the vessel’s structure, where permitted by 4-4-4/1.1.1, are to have suitable
drip pans with adequate means of drainage, in accordance with 4-4-1/9.23.

5 Fuel Oil Service and Injection Systems

Fuel oil service and injection systems for internal-combustion engines are to be in accordance with 4-2-1/3,
4-2-1/5 and 4-2-1/7.

7 Low Flash Point Fuels

7.1 General
Fuel oils with a flash point of 60°C (140°F) closed-cup or below may be accepted for the following:
7.1.1
Vessels classed for restrictive service within areas having a climate ensuring that ambient temperatures
of spaces where such fuel oil is stored will not rise within 10°C (18°F) below its flash point may
use fuel oil with flash point of 60°C (140°F) or below, but not less than 43°C (110°F).
7.1.2
For emergency generators, fuel oil with a flash point of not less than 43°C (110°F) may be used.
See 4-6-2/5.5.2.

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7.3 Fuel Heating

For oil heating arrangements, see 4-4-4/1.5.

7.5 Fuel Oil Tank Vents

Vent pipes are to extend at least 2.4 m (8 ft) above the weather deck or other effective arrangements which
have been approved are to be provided.

9 Lubricating Oil Systems

9.1 General (1998)

The lubricating systems are to be so arranged that they will function satisfactorily under the conditions
specified in 4-1-1/17. The lubricating-oil piping is to be entirely separated from other piping systems. In
addition, the requirements of 4-4-4/1.1.2, 4-4-4/1.3 and 4-4-4/1.5 are applicable.
The requirements in 4-4-4/3.7 are also applicable for lubricating-oil tanks. However, arrangements for
remotely closing the valve from a position outside of the compartment need not be provided if inadvertent
valve closure could result in damage to the running machinery due to lack of lubricating oil. Where the
machinery is arranged for automatic shutdown upon loss of lubricating oil, the valve required by 4-4-4/3.7
is to be provided with means to close it from a readily accessible and safe location outside of the
compartment in which the valve is located.

9.3 Sight Flow Glasses

Sight flow glasses may be used in lubricating systems, provided they are fire-resistant.

9.5 Internal Combustion Engines

For internal combustion engines, see also 4-2-1/9.

9.7 Reduction Gears

For reduction gears, see also 4-2-1/9.11.

9.9 Electrical Machinery

For electrical machinery, see also 4-6-3/3.3, 4-6-3/3.5 and 4-6-4/3.15.

9.11 Hose Reels

Where hose reels are used for filling the engine or reduction gear sumps with oil, a self-closing valve is to
be provided at the end of the filling hose to prevent spillage. Suitable arrangements are to be provided to
properly drain and store the hose and reel when not in use. Hoses are to be approved for oil service and in
accordance with the requirements for burst pressure, fire resistance, reinforcement and end fittings in
4-4-1/9.19.

11 Additional Measures for Oil Pollution Prevention (1 July 2003)

11.1 General (1 August 2007)

11.1.1 Application
The provisions of 4-4-4/11 provide the arrangement of fuel oil tanks for compliance with MARPOL
73/78, as amended. They are to be applied in addition to the requirements of 4-4-4/1 and 4-4-4/3
and are applicable to all types of vessels classed with ABS.
11.1.2 Submission of Plans
Plans showing compliance with the applicable requirements in 4-4-4/11.3 are to be submitted for
review.

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11.3 Tank Protection Requirements (1 August 2007)

11.3.1 General (2009)
The requirements in this section apply to vessels having an aggregate fuel oil capacity of 600 m3
(21,190 ft3) and above. However, the requirements need not be applied to individual fuel oil tanks
with a capacity not greater than 30 m3 (1060 ft3), provided that the aggregate capacity of such
excluded tanks is not greater than 600 m3 (21,190 ft3). Further, individual fuel oil tanks are not to
have capacity greater than 2,500 m3 (88,290 ft3).
Fuel oil tanks of any volume are not to be used for ballast water.
11.3.2 Protective Location of Tanks
The protective locations for the tanks specified in 4-4-4/11.3.1 above are to be as follows:
11.3.2(a) Deterministic Approach (2009). All applicable tanks are to be located away from the
vessel's bottom or side shell plating for a distance as specified in i), ii) or iii). Small suction wells
may extend below fuel oil tanks bottoms, if they are as small as possible and the distance between
the vessel’s bottom plate and the suction well bottom is not reduced by more than half of the
distance required by i).
i) For vessels having an aggregate oil fuel capacity of 600 m3 (21,190 ft3) and above, all
tanks are to be arranged above vessel’s molded line of bottom shell plating at least of the
distance h as specified below:
h = B/20 m or
h = 2.0 m (6.6 ft), whichever is smaller
where B is the breadth of the vessel, as defined in 3-1-1/5, in m (ft).
h is in no case to be less than 0.76 m (2.5 ft).
ii) For vessels having an aggregate oil fuel capacity greater than or equal to 600 m3 (21190 ft3)
but less than 5000 m3 (176570 ft3), tanks are to be arranged inboard of the molded line of
side plating not less than the distance w as specified below:
w = 0.4+2.4C/20000 m w = 1.31+7.87C/706290 ft
where
C = vessel’s total volume of oil fuel in m3 (ft3) at 98% tank filling;
w = at least 1.0 m (3.3 ft)
for individual tanks smaller than 500 m3 (17,657 ft3) w is to be at
least 0.76 m (2.5 ft)
iii) For vessels having an aggregate oil fuel capacity of 5000 m3 (176570 ft3) and above, tanks
are to be arranged inboard of the molded line of side plating not less than the distance w
as specified below:
w = 0.5 + C/20000 m w = 1.64+C/706290 ft or
w = 2.0 m w = 6.6 ft), whichever is smaller
where C is the vessel’s total volume of oil fuel in m3 (ft3) at 98% tank filling.
The minimum value of w=1.0 m (3.3 ft).
11.3.2(b) Probabilistic Approach (2009). As an alterative to the deterministic approach of
4-4-4/11.3.2(a), arrangements complying with the accidental oil fuel outflow performance standard
of Regulation 12A, Annex I, MARPOL 73/78, as amended, would be acceptable.

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Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 4 Fuel Oil and Lubricating Oil Systems and Tanks 4-4-4

11.5 Class Notation – POT (2009)

In addition to the requirements for fuel oil tank protection as specified in 4-4-4/11.3.1 utilizing the deterministic
approach of 4-4-4/11.3.2(a), where lubricating oil tanks are also arranged in the same manner as required
by the deterministic approach [4-4-4/11.3.2(a)] for fuel oil tanks, vessels are to be eligible for the optional
Class notation, POT – Protection of Fuel and Lubricating Oil Tanks. Further, the following exemptions
are applicable to lubrication oil tanks:
i) In application of equation in 4-4-4/11.3.2(a)ii) or iii), total volume of lubricating oil tanks need not
be accounted for C (vessel’s total volume of oil fuel in m3 (ft3) at 98% tank filling).
ii) Tanks used as main engine lubricating oil drain tanks need not be located in a protected location
away from the vessel’s side or bottom plates.

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PART Section 5: Internal Combustion Engine Systems

4
CHAPTER 4 Pumps and Piping Systems

SECTION 5 Internal Combustion Engine Systems

1 Fuel Oil System

Fuel oil systems for internal combustion engines are to comply with 4-2-1/3.

3 Lubricating Oil System

Lubricating oil systems for internal combustion engines are to comply with 4-2-1/9.

5 Cooling Water System

Cooling water systems for internal combustion engines are to comply with 4-2-1/11.

7 Exhaust Piping
Exhaust piping for internal combustion engines is to comply with 4-2-1/15.

9 Starting-air Systems
Starting-air systems for internal combustion engines are to comply with 4-2-1/13.

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PART Section 6: Hydraulic and Pneumatic Systems

4
CHAPTER 4 Pumps and Piping Systems

SECTION 6 Hydraulic and Pneumatic Systems

1 Hydraulic Systems

1.1 General
The arrangements for Group I hydraulic piping systems are to be in accordance with the requirements of
this section, except that hydraulic systems which form part of a unit which is independently manufactured
and assembled and which does not form part of the vessel’s piping system (such as a crane) are not
covered by this section.
Plans clearly showing the arrangements and details are to be submitted for review.
Hydraulic pumps, actuators, motors and accessories are to be suitable for the intended duty, compatible
with the working fluid and are to be designed to operate safely at full power conditions. In general, the
hydraulic fluid is to be non-flammable or have a flash point above 157°C (315°F).
The requirements for fuel oil tanks contained in 4-4-4/1.1.2 and 4-4-4/1.3 are applicable to tanks containing
hydraulic fluid. See also 4-3-3/7 and 4-3-2/17.

1.3 Valves
1.3.1 General
In general, valves are to comply with the requirements of 4-4-2/9 and 4-4-2/11.
1.3.2 Relief Values
Relief valves are to be provided for the protection of the hydraulic system. Each relief valve is to
be capable of relieving not less than full pump flow with a maximum pressure rise of not more
than 10% of the relief valve setting.

1.5 Piping
Piping is to meet the requirements of 4-4-1/5 and 4-4-2/5, except that mill tests need not be witnessed by
the Surveyor. In such cases, mill certificates are to be provided which verify the chemical and mechanical
properties for the pipe.

1.7 Pipe Fittings

Fittings and flanges are to meet the requirements of 4-4-2/9, 4-4-2/13 and 4-4-2/17, except as follows:
1.7.1 Split Flanges (2004)
Split flanges are not to be used in steering gear systems, certified thruster systems, nor in systems
which are vital to the propulsion or safety of the vessel. Split flanges may be considered for use in
other systems. Where split flanges are permitted, they are not to be used to join sections of piping,
but may be used for connections to machinery, provided the materials and construction are
suitable for the system design pressure.
1.7.2 Straight-Thread “O”-Ring Connection
Straight-thread “O”-ring type connections may be used for connections to equipment such as
pumps, valves, cylinders, accumulators, gauges and hoses. Such connections are not to be used for
joining sections of pipe.

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Chapter 4 Pumps and Piping Systems
Section 6 Hydraulic and Pneumatic Systems 4-4-6

1.7.3 Tapered Threaded Connection

Tapered threaded connections up to and including 89 mm O.D. (3 in. NPS) may be used without
limitation for connections to equipment such as pumps, valves, cylinders, accumulators, gauges
and hoses. Tapered threaded connections are not to be used in steering gear systems, controllable
pitch propeller systems, and other systems associated with propulsion or propulsion control,
except where permitted by 4-4-2/13.1. Such connections are not to be used for joining sections of
pipe, except where permitted by 4-4-2/13.1.

1.9 Accumulators and Fluid Power Cylinders

Accumulators are to meet the requirements of Part 4, Chapter 4 of the Steel Vessel Rules. Each accumulator
which may be isolated is to be protected by suitable relief valves. Where a gas charging system is used, a
relief valve is to be provided on the gas side of the accumulator.
Fluid Power Cylinders are to meet the requirements of 4-4-6/3.

1.11 Design Pressure

The pressure used for determining the strength and design of piping and components is not to be less than
the relief valve setting.

1.13 Segregation of High Pressure Hydraulic Units

Hydraulic units with working pressures above 15.5 bar (15.8 kgf/cm2, 225 psi) installed within a machinery
space are to be placed in separate room or rooms or shielded as necessary to prevent any oil or oil mist that
may escape under pressure from coming into contact with surfaces with temperatures in excess of 220°C
(428°F), electrical equipment or other sources of ignition. For the purpose of this requirement, a hydraulic
unit includes the power pack and all components of the hydraulic piping system.

3 Fluid Power Cylinders (1 July 2009)

3.1 General
Fluid power cylinders subject to pressures or temperatures greater than those indicated below are to be
designed, constructed and tested in accordance with a recognized standard for fluid power cylinders.
• Hydraulic fluid – flammable: 7 bar (7.1 kgf/cm2, 101.5 psi) or 60°C (140°F)
• Hydraulic fluid – non-flammable: 16 bar (16.3 kgf/cm2, 232 psi) or 200°C (392°F)
• Air: 16 bar (16.3 kgf/cm2, 232 psi) or 200°C (392°F)
Acceptance will be based on the manufacturer’s certification of compliance and on verification of permanent
identification on each cylinder bearing the manufacturer's name or trademark, standard of compliance and
maximum allowable working pressure and temperature.

3.3 Non-compliance with a Recognized Standard

Cylinders subject to pressures or temperatures higher than those indicated above which are not constructed
to a recognized standard may be accepted based on the following:
i) Regardless of diameter, the design of the cylinder is to be shown to comply with one of the following:
• A recognized pressure vessel code,
• Section 4-4-1 of the Steel Vessel Rules. For instance, the cylinder is to have a wall thickness
not less than that given by equation 2 of 4-4-1A1/3.1, and the cylinder ends are to meet the
requirements of flat heads in 4-4-1A1/5.7, or
• Verification through burst tests. Steel cylinders (other than cast steel) are to withstand not less
than 4 times the maximum allowable working pressure, while cast steel, cast iron and nodular
iron cylinders are to withstand not less than 5 times the maximum allowable working pressure.
Documentation in this regard is to be submitted for review.

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Section 6 Hydraulic and Pneumatic Systems 4-4-6

ii) Each individual unit is to be hydrostatically tested to 1.5 times the maximum allowable working
pressure (2 times, for cast iron and nodular iron cylinders) by the manufacturer. A test certificate is
to be submitted.
iii) Each cylinder is to be affixed with a permanent nameplate or marking bearing the manufacturer’s
name or trademark and the maximum allowable working pressure and temperature.

3.5 Materials
i) The materials of the cylinders are to comply with the requirements of the standard or code to which
they are designed and constructed. Where the design is verified though burst tests, the materials of
the cylinder are to comply with 4-4-1/3 of the Steel Vessel Rules or other acceptable standards.
ii) Ordinary cast iron having an elongation of less than 12% is not to be used for cylinders expected
to be subjected to shock loading.
iii) Copies of certified mill test reports are to be made available to the Surveyor upon request.

3.7 Rudder Actuators

Rudder actuators are to be in accordance with the requirements of 4-3-3/5.11.

3.9 Cylinders below Pressures or Temperatures Indicated in 4-4-6/3.1

Cylinders subject to pressures and temperatures at or below those indicated in 4-4-6/3.1 may be used in
accordance with the manufacturer’s rating and verification of suitable for the intended service.

3.11 Independently Manufactured and Assembled Units

Cylinders forming a part of an independently manufactured and assembled unit that do not form part of
vessel’s piping system are not covered by this subsection.

5 Pneumatic Systems (2005)

5.1 Application
Requirements of 4-4-6/5 apply to shipboard pneumatic systems for control and actuation services. Requirements
for starting air systems are in 4-2-1/13. Pneumatic systems fitted in self-contained equipment not associated
with propulsion and maneuvering of the vessel and completely assembled by the equipment manufacturer
need not comply with this subsection. Such pneumatic systems, however, are to comply with the accepted
practice of the industry

5.3 Pneumatic System Components

5.3.1 Air Reservoirs
The design and construction of all air receivers are to be in accordance with the applicable
requirements of Part 4, Chapter 4 of the Steel Vessel Rules.
5.3.2 Pipe Fittings and Joints
The piping system and its components are to be in accordance with the applicable requirements of
Part 4, Chapter 4 of these Rules.

5.5 Pneumatic System Requirements

5.5.1 Pneumatic Air Source
Compressed air for general pneumatic control and actuation services may be drawn from engine
starting air reservoirs. In which case, the aggregate capacity of the starting air reservoirs is to be
sufficient for continued operation of these services after the air necessary for the required number
of engine starts (as specified in 4-2-1/13.3.1) has been used.

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Section 6 Hydraulic and Pneumatic Systems 4-4-6

For propulsion remote control purposes, pneumatic air is to be available from at least two air
compressors. The starting air system, where consisting of two air compressors, may be used for this
purpose. The required air pressure is to be automatically maintained. Pneumatic air supplies to safety
and control systems may be derived from the same source but are to be by means of separate lines
5.5.2 Air Quality (2010)
5.5.2(a) General. Provisions are to be made to minimize the entry of oil or water into the compressed
air system. Suitable separation and drainage arrangements are to be provided before the air enters
the reservoirs.
5.5.2(b) Safety and Control Air Systems. For requirements regarding the quality of the air supplied
to safety and control air systems, see 4-7-2/11.1.4.
5.5.3 Overpressure Protection
Means are to be provided to prevent overpressure in any part of the pneumatic system. This
includes the water jackets or casings of the air compressors and coolers which may be subjected to
dangerous over-pressure due to leakage into them from the air pressure parts.

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PART Section 7: Cargo Systems

4
CHAPTER 4 Pumps and Piping Systems

SECTION 7 Cargo Systems

Note: Vessels classed as Oil Carrier in accordance with Part 5C, Chapter 2 of the ABS Rules for Building and Classing
Steel Vessels are to meet the additional requirements in 4-4-7/1 through 4-4-7/5 of these Rules.

1 Cargo Pumps

1.1 Construction
Cargo pumps are to be so designed as to minimize the danger of sparking.

1.3 Installation
Care is to be taken to prevent leaks at the stuffing box. Where the shafts pass through gastight bulkheads,
flexible couplings are to be provided in shafts between the pumps and prime movers, and stuffing boxes
which can be lubricated from outside of the pump room are to be fitted at the bulkheads. The seal parts of
the glands are to be of non-sparking construction. If a bellows piece is incorporated in the design, it is to be
pressure-tested before being fitted.
Cargo pumps, ballast pumps and stripping pumps installed in cargo pump rooms and driven by shafts
passing through pump room bulkheads are to be fitted with temperature sensing devices for bulkhead shaft
glands, bearings and pump casings. High temperature alarms (audible and visual) are to be provided at the
cargo control room or the pump control station.

1.5 Relief Valve and Bypass

A relief valve of suitable type is to be installed in the discharge of each pump, except as noted in 4-4-1/9.15,
and piped back into the suction. A bypass is to be provided around the pump for use when loading through
the suction piping.

1.7 Pressure Gauges

One pressure gauge for each pump is to be located at the pump discharge, and where the pumps are
operated by engines or motors external to the pump room, additional gauges are to be provided which are
visible from the operating station.

1.9 Integrated Cargo and Ballast Systems (2004)

For integrated cargo and ballast systems, see 4-6-6/1.21.

3 Cargo Piping Systems

3.1 General (1998)

Cargo piping systems are to be independent of all other piping systems and are not to pass through fuel oil
tanks nor spaces containing machinery where sources of vapor ignition are normally present. Provisions
are to be made for expansion of the cargo piping system.

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Section 7 Cargo Systems 4-4-7

For vessels of 5000 tons deadweight and above, cargo piping, including vent and sounding piping for cargo
tanks, is not to pass through ballast tanks, except for short runs of welded steel extra heavy pipe or equivalent
construction.
For vessels less than 5000 tons deadweight, cargo piping passing through ballast tanks is to be steel of
extra heavy or equivalent construction. In the portion of the cargo piping located within the ballast tank,
only expansion bends (not glands) are to be installed to allow for expansion and contraction stresses. All
joints within the ballast tanks are to be welded or have extra heavy flanges. The number of flanged joints is
to be kept to a minimum.
Where requested by the Owner, vessels in which all cargo piping and valve control piping is located above
the double bottom will be distinguished in the Record by the notation CPP (Cargo Piping Protected). The
CPP notation is not a condition of classification.
Cargo loading pipes are to be led as low as practicable in the cargo tank. Also see 4-4-1/9.21 and 4-4-2/3.5.

3.3 Cargo Tank Ballasting

3.3.1 Suction
Where it is necessary to provide a sea suction to the cargo oil pumps for severe weather ballasting,
tank cleaning or other purposes, means of isolating the pumps from the sea chest is to be provided.
The means of isolation is to be either a blank flange or a removable spool piece. A shut-off valve
is to be fitted on each side of the blank flange or spool piece. As an alternative, the means of isolation
may be two valves located inboard of the sea chest, one of which is to be capable of being locked
in the closed position. Means are to be provided for detecting leakage past these valves.
3.3.2 Discharge
The discharge system is to be so designed as to enable ballast water which is carried in cargo tanks
to be processed and discharged in accordance with Regulation 9 of Annex I to the International
Convention for the Prevention of Pollution from Ships (MARPOL) 1973/1978, as amended.

3.5 Bow or Stern Loading and Unloading (1998)

Where bow or stern loading or unloading connections are provided, cargo lines forward or aft of the cargo
area are to be led outside accommodation spaces, service spaces, machinery spaces and control stations. Pipe
joints outside the cargo area are to be welded, except for connections to the manifold or loading/unloading
equipment.
The cargo loading/unloading lines are to be clearly identified and provided with means to segregate them
from the cargo main line when not in use. The segregation is to be achieved by either two valves located in
the cargo area which can be locked in the closed position and fitted with means to detect leakage past the
valves, or by one valve together with another closing device providing an equivalent standard of segregation,
such as a removable spool piece or spectacle flange.
The loading/unloading connection is to be fitted with a shut-off valve and a blank flange. The blank flange
may be omitted if an equivalent means of closing is incorporated in the connection to the hose coupling.
Arrangements are to be provided for cargo lines outside of the cargo area for easy draining to a slop tank or
cargo tank and for cleaning and inerting. Spill containment is to be provided under the loading and unloading
manifolds. The space within 3 m (10 ft) of the manifold and oil spill containment boundary is to be considered
as a restricted area with regard to electrical equipment or other sources of vapor ignition.

3.7 Operating-rod Stuffing Boxes

Stuffing boxes are to be fitted where operating rods from cargo valves pass through gastight structural parts.

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Chapter 4 Pumps and Piping Systems
Section 7 Cargo Systems 4-4-7

5 Other Piping Systems on Oil Carriers

5.1 Pump-room and Cofferdam Bilge Systems (2009)

Provision is to be made for removing drainage from the pump-room bilges and adjacent cofferdams. A
separate bilge pump, eductor or a bilge suction from a cargo pump or cargo stripping pump may be provided
for this purpose. The pump is not to be located in, nor is the piping to pass through, spaces containing machinery
where sources of vapor ignition are normally present. Where a bilge suction is provided from a cargo or
stripping pump, a stop-check valve is to be fitted in the bilge suction branch. An additional stop valve is to
be fitted when the bilge suction branch is arranged so that it may be subjected to a head of oil from the
filling line. Pump-room bilge suction and discharge valves and bilge-pump controls are to be operable
from in the pump room, unless Flag Administrations have a specific requirement for remote operation,
either from an accessible position outside the pump-room or from the pump-room casing above the
freeboard deck. High levels of liquid in the pump room bilges is to activate an audible and visible alarm in
the cargo control room and on the navigation bridge.

5.3 Machinery Space Bilge System

Where bilge slops from other than the cargo pump room are discharged into a cargo slop tank, the discharge
piping is to be arranged as follows.
i) Enters the cargo slop tank from the weather deck through the tank top.
ii) The tank penetration is located as close to a vertical tank boundary as practicable.
iii) Within the tank, the line is as short as practicable and is arranged to discharge against the vertical
boundary.
iv) A stop-check valve is provided in the discharge line and is located within the engine room as close
to the engine room bulkhead as possible.
v) A loop seal is to be located in the cargo pump room or other suitable location outside of the engine
room. The height of the loop seal is to provide a static head pressure greater than the pressure
setting of the cargo slop tank P/V valve or a minimum of 762 mm (30 inches), whichever is
greater. A means is to be provided to prevent the loop seal from freezing.
vi) A non-return valve is to be located in the discharge line on deck as close to the tank penetration as
practicable.

5.5 Ballast Piping (2004)

For vessels of 5000 gross tons and above, ballast piping, including vent and sounding piping for ballast tanks,
is not to pass through cargo tanks, except for short runs of welded steel extra heavy pipe or equivalent
construction.
For vessels less than 5000 tons deadweight, ballast piping passing through cargo tanks is to be steel of extra
heavy or equivalent construction. All joints within the cargo tanks are to be welded or have extra heavy
flanges. The number of flanged joints is to be kept to a minimum. In the portion of the ballast piping located
within the cargo tank, only expansion bends (not glands) are to be installed to allow for expansion and
contraction stresses.
Ballast piping permitted to pass through cargo or connected to ballast tanks adjacent to cargo tanks is not
to pass through spaces where sources of vapor ignition are normally present. Connections to the fire main
for ballasting or deballasting with eductors are to be fitted with a non-return valve.
Arrangements may be provided in the cargo pump room or on deck, in the case of vessels without a cargo
pump room, for a temporary connection between cargo and ballast piping by means of a portable spool piece,
and are to have a non-return valve to prevent cargo from entering the ballast system and shut-off valves
with blind flanges on both the ballast and cargo piping connections. Temporary connections are to be reported
to the Surveyor.
For integrated cargo and ballast systems, see 4-6-6/1.21.

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Section 7 Cargo Systems 4-4-7

5.7 Piping Through Cargo Tanks

Where the arrangement of the vessel is such as to necessitate the passing through the cargo tanks of piping
other than that necessary for the handling or heating of the cargo or for fire protection, the piping systems
will be subject to special consideration.

5.9 Cargo Heating Systems

5.9.1 General
The medium used to directly heat the cargo oil is to be contained solely within the cargo area
unless the return line of the heating system is led to an inspection tank. The inspection tank is to
be of a closed type, dedicated to the cargo heating system and vented to the weather. A corrosion-
resistant flame screen is to be fitted at the vent outlet. The inspection tank may be located within
the main machinery space, in which case, the vent is to terminate outside of the cargo deck area
and is not to be located within 3 m (10 ft) of ventilation intakes or sources of ignition. Cargo
heating piping within cargo tanks is to be all welded or brazed, except that the use of a limited
number of flanged joints to facilitate installation and repair will be specially considered.
5.9.2 Thermal Oil Installations
Where thermal oil heating systems are used, they are to comply with the requirements in 5C-1-7/9
of the Steel Vessel Rules.

5.11 Slop Tanks in Combination Carriers

Slop tanks in vessels alternately carrying oil or dry bulk cargoes are to have an approved independent venting
system. A completely separate pumping system is to be provided for the slop tanks or, alternatively, all
suction and filling connections for the slop tanks are to be provided with spectacle blank flanges. Suitable
warning notices are to be posted when carrying dry cargo with flammable liquids or vapors in the slop tanks.

5.13 Duct Keels in Double Bottoms

Duct keels or pipe tunnels are not to pass into machinery spaces. Provision is to be made for at least two
exits to the open deck arranged at a maximum distance from each other. One of these exits fitted with a
watertight closure may lead to the cargo pump room. Provision is to be made in the duct for adequate
mechanical ventilation.

5.15 Cargo Venting Systems

Cargo tank venting systems for oil carriers are to be in accordance with Regulation II-2/4.5.3 of SOLAS
1974, as amended and the following.
5.15.1 P-V Valve Setting
The pressure setting of pressure-vacuum relief valves is not to exceed 0.18 bar (0.18 kgf/cm2, 2.6 psi)
above atmospheric for vessels of 90 m (295 ft) in length and 0.12 bar (0.12 kgf/cm2, 1.7 psi) for
vessels of 61 m (200 ft) in length or less. For intermediate lengths, intermediate pressures will
apply. The vacuum setting is to be at a pressure equal or less than 0.07 bar (0.07 kgf/cm2, 1 psi)
below atmospheric.
Positive pressures up to and including 0.70 bar (0.70 kgf/cm2, 10 psi) gauge will be allowed in
specially designed integral tanks. See 5C-2-1/1.15 of the Steel Vessel Rules.
Calculations are to be submitted showing that cargo tanks will not be subjected to a pressure in
excess of the P-V valve setting.
5.15.2 Liquid Level Control
Provision is to be made to guard against liquid rising in the venting system to a height that would
exceed the design head of the cargo tanks. This may be accomplished by using high level alarms
or overflow control systems or other equivalent means together with gauging devices and tank
filling procedures. In this regard, as applicable, a vent/overflow control system analysis for the
protection of the cargo tanks is to be submitted for review. This system analysis is to clearly
indicate the anticipated worst load/unload condition criteria.

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Section 7 Cargo Systems 4-4-7

5.15.3 Flame Screens

Vent outlets from cofferdams and from ballast tanks adjacent to cargo oil tanks are to be fitted
with corrosion-resistant flame screens having a clear area through the mesh of not less than the
area of the pipe.
5.15.4 Isolation
For vessels fitted with inert gas systems, arrangements are to be provided to protect cargo tanks
against the effect of overpressure or vacuum caused by thermal variations when the cargo tanks
are isolated from inert gas systems.

5.17 Inert-gas System

When tank vessels are equipped with a system whereby inert gas is continuously maintained in the tanks,
such a system is to be in accordance with Section 3-4-1 and the following.
5.17.1 General
The inert gas may be treated flue gas from boiler(s) or from a separate inert gas generator. In all
cases, automatic combustion control suitable for operation under all service conditions is to be
fitted. Any proposal to use other sources of inert gas will be specially considered.
5.17.2 Pressure
The systems are to be so designed that the maximum pressure which can be exerted on the tank(s)
does not exceed 0.24 bar (0.24 kgf/cm2, 3.5 psi).
5.17.3 Blower Isolating Valves
Shut-off valves are to be fitted on both suction and discharge connections for each blower.
5.17.4 Demister
Demisters or equivalent devices are to be provided to minimize carry-over of water from the scrubber
and the deck water seal.
5.17.5 Gas Regulating Valve
The gas regulating valve is to be arranged to close automatically when any of the following
additional conditions apply.
• Loss of water pressure to deck seal(s)
• Loss of control power
5.17.6 Blowers
When two blowers are provided, the total required capacity of the inert gas system is preferably to
be divided equally between the two blowers and in no case is one blower to have a capacity less
than 1/3 of the total capacity required.
5.17.7 Scrubber Cooling Pump
A minimum of two pumps are to be provided for inert gas scrubber cooling, one of which is to be
dedicated for only this service. Pumps, other than the required dedicated pump, may be used for
other services such as bilge, ballast or general service.
5.17.8 Oil-Fired Inert Gas Generators
5.17.8(a) Fire protection. The compartment in which any oil-fired inert gas generator is situated
is to meet the requirements of 4-5-1/9, 4-5-2/9 and 4-5-2/19.
5.17.8(b) Venting. Arrangements are to be made to vent the inert gas from oil-fired inert gas
generators to the atmosphere when the inert gas produced is off-specification, e.g., during starting-
up or in the event of equipment failure.
5.17.8(c) Fuel Oil Shutdown. Automatic shutdown of the fuel oil supply to inert gas generators is
to be arranged on predetermined limits being reached in respect of low water pressure or low water
flow rate to the cooling and scrubbing arrangement and in respect of high gas temperature.

140 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 7 Cargo Systems 4-4-7

5.17.9 Pump Certification

The fuel oil pumps serving the boiler or inert gas generator and the cooling water pumps serving
the flue gas scrubber are to be certified in accordance with 4-4-2/1.

5.19 Cargo Vapor Emission Control Systems

Cargo vapor emission control systems, where provided, are to be in accordance with 5C-1-7/21 of the Steel
Vessel Rules.

5.21 Crude Oil Washing

When tank vessels are equipped with a system whereby crude oil is utilized for the washing of tanks, the
valves, piping and other fittings are to be in accordance with 4-4-7/3.1 for cargo piping.

7 Cargo Oil Systems on Vessels Other Than Bulk Oil Carrier Type

7.1 Cargo-tank Valves in Dry-cargo Vessels

The control arrangement for valves at the sides of cargo-oil tanks, fitted in dry-cargo vessels, is to be in
accordance with 4-4-4/3.7.

7.3 Edible-oil Cargoes

The arrangement for carriage of edible oils will be subject to special consideration.

7.5 Venting System for High Flash Point Cargoes

Where a vessel is intended only for the carrying of combustible liquids having a flash point above 60°C
(140°F), closed cup test, a venting system consisting of individual return-bend vents fitted with flame screens
may be fitted in lieu of that described in 4-4-7/5.15.

9 Cargo-Handling Systems for Dry Bulk Self-Unloading Vessels

Dry bulk cargo vessels are to meet the following additional requirements when fitted with self-unloading
cargo-handling equipment.

9.1 Fail-Safe Arrangements and Safety Devices

Fail-safe arrangements and safety devices are to be provided on the self-unloading equipment. A system is
considered fail-safe if a component failure or loss of power will result in a controlled securing of the
equipment or control of movement so as not to endanger personnel.

9.3 Hydraulic Piping Installations

The passage of self-unloading system hydraulic pipes through cargo holds is to be limited to only that
which is necessary for operational purposes. Pipes installed within cargo holds are to be protected from
mechanical damage.
System connection to other hydraulic systems is subject to special consideration. Failure in any one part of
the self-unloading hydraulic system is not to cause the failure of other parts of the self-unloading system or
of other ship’s systems.

9.5 Electrical, Control, Alarm and Monitoring Equipment Installation

For requirements regarding electrical equipment, controls, alarms, monitors and hazardous areas (as applicable),
see 4-6-3/9 and 4-6-6/3.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 141
PART Section 8: Other Piping Systems and Tanks

4
CHAPTER 4 Pumps and Piping Systems

SECTION 8 Other Piping Systems and Tanks

1 Fixed Oxygen-Acetylene Installations (2003)

1.1 Application (2005)

Provisions of 4-4-8/1.3 apply to fixed oxygen-acetylene installations that have two or more cylinders of
oxygen and acetylene, respectively. Spare cylinders of gases need not be counted for this purpose. Provisions
of 4-4-8/1.5 and 4-4-8/1.7, as applicable, are to be complied with for fixed installations regardless of the
number of cylinders.

1.3 Gas Storage

1.3.1 Storage of Gas Cylinders
1.3.1(a) Storage room. The gas cylinders are to be stored in rooms dedicated for this purpose only.
A separate room is to be provided for each gas. The rooms are to be on or above the upper-most
continuous deck and are to be constructed of steel. Access to the rooms is to be from the open
deck and the door is to open outwards. The boundaries between the rooms and other enclosed
spaces are to be gastight. Suitable drainage of the storage room is to be provided.
1.3.1(b) Open area. Where no storage room is provided, the gas cylinders may be placed in an
open storage area. In such cases, they are to be provided with weather protection (particularly
from heavy seas and heat) and effectively protected from mechanical damage. Suitable drainage of
the open storage area is to be provided.
1.3.1(c) Piping passing through storage room or area. Piping systems containing flammable
fluids are not to run through the storage room or open storage area
1.3.2 Ventilation of Storage Room
Gas cylinder storage rooms are to be fitted with ventilation systems capable of providing at least
six air changes per hour based on the gross volume of the room. The ventilation system is to be
independent of ventilation systems of other spaces. The space within 3 m (10 ft) from the power
ventilation exhaust, or 1 m (3 ft) from the natural ventilation exhaust is to be considered a hazardous
area. The fan is to be of a non-sparking construction. See 4-6-3/11.7. Small storage spaces provided
with sufficiently large openings for natural ventilation need not be fitted with mechanical ventilation.
1.3.3 Electrical Installation in Storage Room (2008)
Electrical equipment installed within the storage room, including the ventilation fan motor, is to be
of a certified safe type. Electrical equipment installed within the storage room may be any of the
types indicated in 4-6-3/11.1.1 and is to be IEC Publication 60079 group IIC class T2.

1.5 Piping System Components

1.5.1 Pipe and Fittings
1.5.1(a) General (2011). In general, all oxygen and acetylene pipes, pipe fittings, pipe joints and
valves are to be in accordance with the provisions of Section 4-4-2 for Group I piping systems,
except as modified below. Further, only high pressure oxygen and acetylene piping is to be certified
as Group I piping, see 4-4-1/5.1 for the materials testing.

142 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 8 Other Piping Systems and Tanks 4-4-8

1.5.1(b) Piping materials (2010). Materials for acetylene on the high-pressure side between the
cylinders and the regulator are to be steel. Copper or copper alloys containing more than 65% copper
are not to be used in acetylene piping (high or low pressure). Materials for oxygen on the high-
pressure side are to be steel or copper. All pipes, both high- and low-pressure sides, are to be seamless.
1.5.1(c) Design pressure (2006). Pipes, pipe fittings and valves on the oxygen high-pressure side
are to be designed for not less than 207 bar (211 kgf/cm2, 3000 psi). Pipes used on the low-pressure
side are to be at least of standard wall thickness.
1.5.1(d) Pipe joints. All pipe joints outside of the storage room or open storage area are to be welded.
11.5.1(e) Flexible hoses (2009). Flexible hoses used to connect oxygen or acetylene gas cylinders
to a fixed piping system or manifold are to comply with an acceptable standard and be suitable for
the intended pressure and service. Further, the internal surface of a hose used to connect an acetylene
tank is to be of a material that is resistant to acetone and dimethylformamide decomposition*.
Where a flexible hose is connected from an oxygen cylinder to the piping system or manifold
directly (i.e., no intervening pressure regulator), the internal liner of the oxygen hose is to be of a
material that has an autoignition temperature of not less than 400°C (752°F) in oxygen*.
* Note: Criteria based on ISO 14113:1997 Gas welding equipment – rubber and plastic hoses assembled for
compressed or liquefied gases up to a maximum design pressure of 450 bar.

1.5.2 Pressure Relief Devices

Pressure relief devices are to be provided in the gas piping if the maximum design pressure of the
piping system can be exceeded. These devices are to be set to discharge at not more than the
maximum design pressure of the piping system to a location in the weather, remote from sources
of vapor ignition or openings to spaces or tanks. The area within 3 m (10 ft) of the pressure relief
device discharge outlet is to be regarded as a hazardous area. The pressure relief devices may be
either a relief valve or a rupture disc.
1.5.3 System Arrangements
Where two or more gas cylinders are connected to a manifold, high pressure piping between each
gas cylinder and the manifold is to be fitted with a non-return valve. The piping is not to run
through unventilated spaces or accommodation spaces. Outlet stations are to be fitted with shut-off
valves. Outlet stations are to be provided with suitable protective devices to prevent back flow of
gas and the passage of flame into the supply lines.
1.5.4 Gas Cylinders
Gas cylinders are to be designed, constructed and certified in accordance with the provisions of
4-4-1/1.11.4 of the Steel Vessel Rules. Each cylinder is to be fitted with a suitable pressure relief
device such as a fusible plug or a rupture disc.
The area within 3 m (10 ft) of the pressure relief device discharge outlet is to be regarded as a
hazardous area.

1.7 Testing (2006)

Piping on the oxygen high-pressure side is to be tested before installation to at least 207 bar (211 kgf/cm2,
3000 psi) and the piping on the acetylene high-pressure side is to be tested in accordance with Section 4-4-2.
The entire system is to be leak-tested with nitrogen or a suitable inert gas after installation. Care is to be
taken to cleanse the piping with suitable medium to remove oil, grease and dirt and to blow-through with
oil-free nitrogen or other suitable medium before putting the system in service. The system is to be
operationally tested in the presence of the Surveyor under working conditions after installation.

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Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 8 Other Piping Systems and Tanks 4-4-8

3 Fuel Storage and Refueling Systems for Helicopter Facilities

3.1 Fuels with Flash Point Above 60°C (140°F)

When fixed helicopter fuel storage and pumping systems are provided and the flash point of the fuel is
above 60°C (140°F), closed cup test, the installation is to comply with 4-4-4/1, 4-4-4/3 and 4-4-8/3.3.5.

3.3 Fuels with Flash Point at or Below 60°C (140°F) – Installations on an Open Deck
3.3.1 General
The designated fuel storage and refueling areas are to be suitably isolated from areas which contain a
source of vapor ignition, escape routes and embarkation stations, and are not to be located on landing
areas. The storage and refueling areas are to be permanently marked as an area where smoking and
open flames are not permitted.
3.3.2 Tanks
Fixed fuel storage tanks are to be of metal construction. Mounting, securing arrangements and
electrical bonding of the storage tank and refueling system are to be approved.
3.3.3 Vents and Sounding
Fuel storage tank venting and sounding arrangements are to comply with 4-4-3/9.5, 4-4-3/9.7, 4-4-4/7.5
and 4-4-3/13.
3.3.4 Tank Valves
Fuel storage tank outlet valves are to be provided with a means of remote closure. Means are also
to be provided for remote shutdown of the refueling pumps.
3.3.5 Spill Containment
To contain spillage and retain fire extinguishing agents, a coaming of at least 150 mm (6 in.) in height
is to be provided. The coaming is to surround the fuel storage area, which consists of the fuel tank,
associated piping and any pumping unit adjacent to the storage tank. Where the pumping unit is
remote from the tank, a separate coaming is to be provided around the pumping unit.
Drainage is to be provided for the area enclosed by the coaming, complying with the following:
i) The area within the coaming is to be sloped toward the drain line.
ii) Drainage from the area within the coaming is to be led through a valve designed for
selective output (e.g., 3-way valve) either to a holding tank complying with 4-4-8/3.3.2
and 4-4-8/3.3.3 above or directly overboard. No other valves may be fitted in the drain line.
iii) The drain line cross sectional area is to be at least twice that of the fuel storage tank outlet
connection.
Coamings not provided with drainage arrangements in accordance with the above are to be sized
to contain the full volume of the fuel storage tank plus 150 mm (6 in.) of foam.
3.3.6 Electrical Equipment (2008)
All electrical equipment installed within 3 meters (10 ft) of either the tank vent outlet or the
pumping/refueling equipment is to be of a certified safe type. Electrical equipment installed may
be any of the types indicated in 4-6-3/11.1.1 and is to be IEC Publication 60079 group IIA class T3.

3.5 Fuels with Flash Points at or Below 60°C (140°F) – Installation within Enclosed Spaces
3.5.1 Independent Tanks
Fuel storage tanks and their venting and sounding arrangements are to comply with 4-4-8/3.3.2
and 4-4-8/3.3.3. The valving arrangements on the tanks are to comply with 4-4-4/3.7.

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Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 8 Other Piping Systems and Tanks 4-4-8

3.5.2 Integral Tanks

The venting and sounding arrangements for integral tanks are to comply with 4-4-8/3.3.3. Overflow
and valving arrangements are to comply with 4-4-3/11 and 4-4-4/3.7, respectively. Cofferdams
meeting the requirements of 5C-2-1/5.3 of the Steel Vessel Rules are to be provided to separate
fuel tanks from the spaces mentioned therein.
3.5.3 Access Arrangements
The access to the fuel storage and refueling compartment is to be from the open deck by means of
a trunk, if necessary. The compartment is to be bounded by gas tight bulkheads/decks and there is
to be no direct access from any other compartment to the fuel storage and refueling compartment
or access trunk.
3.5.4 Electrical Equipment (2008)
Electrical equipment installed in the refueling pump room and the space in which an independent
helicopter fuel tank storage is located is to be of a certified safe type. All electrical equipment
installed within three (3) meters (10 ft) of the tank vent outlet is to be of a certified safe type.
Electrical equipment installed may be any of the types indicated in 4-6-3/11.1.1 and is to be IEC
Publication 60079 group IIA class T3.
3.5.5 Pumps
Fuel pumps for helicopter refueling are to comply with 4-4-7/1 and are to be provided with remote
shut-down.
3.5.6 Piping
Helicopter refueling piping systems are to comply with 4-4-7/3.1.
3.5.7 Bilge/Drainage System
Provision is to be made for drainage of the refueling pump room and cofferdams. A separate bilge
pump, ejector or a bilge suction from a refueling pump may be provided for this purpose. The
arrangements are to be in accordance with 4-4-7/5.1.
3.5.8 Ventilation
Systems for the refueling pump room and the space in which an independent helicopter fuel tank
is located are comply with 4-6-6/1.13.1.

5 Liquefied Petroleum Gases

5.1 General
Liquefied petroleum gas may be used for cooking and heating on all vessels except passenger vessels.
Liquefied petroleum gas systems are to be of the vapor withdrawal type only. Cylinders designed to admit
the liquid phase of the gas into any other part of the system are prohibited. All component parts of the
system, except cylinders, appliances and low pressure tubing, shall be designed to withstand a pressure of
34 bar (35 kgf/cm2, 500 psi) without rupture.

5.3 Storage Cylinders

Cylinders for the storage of liquefied petroleum gases are to be designed and constructed in accordance
with a recognized pressure vessel standard.

5.5 Installation and Testing

Where liquefied petroleum gases are used, the installation and testing is to comply with a recognized
standard.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 145
Part 4 Vessel Systems and Machinery
Chapter 4 Pumps and Piping Systems
Section 8 Other Piping Systems and Tanks 4-4-8

7 Chemical and Gas Carriers

Where vessels are intended to carry hazardous cargoes such as chemicals or liquefied gases, Part 5C,
Chapters 8 and 9 of the Steel Vessel Rules are applicable.

9 Offshore Support Vessels

Where it is intended to carry limited amounts of hazardous and noxious liquid substances in bulk on offshore
support vessels, the arrangement is to comply with Part 5, Chapter 10.

11 Ammonia System

11.1 Compartmentation
Ammonia handling machinery is to be installed in a dedicated compartment with at least two access doors.
The doors are to be of the self-closing, gastight type with no hold-back arrangements.

11.3 Safety Measures

The following safety measures are to be provided for compartments containing ammonia handling machinery,
including process vessels.
i) An independent mechanical negative ventilation system capable of providing at least 30 air changes
per hour based on the gross volume of the space
ii) A sprinkler system with control outside of the compartment
iii) A fixed ammonia detector system with alarm inside and outside of the compartment
iv) Water screen devices operable from outside of the compartment, for all access doors.
v) An independent bilge system located within these compartments

11.5 Ammonia Piping

Ammonia piping is not to pass through accommodation spaces.

13 Liquid Mud Cargo Tanks (2006)

Liquid mud cargo tanks are to be provided with vent pipes complying with 4-4-3/9. In order to prevent
overpressure or underpressure in the event of overflow into the vent pipe or clogging of the flame screen in
the case of oil based mud, vents for liquid mud tanks are to also be provided with a suitable burst disc(s)
rated below the mud tank design pressure. Spare burst discs are to be carried on board so that damage burst
disc can be replaced. Suitable means of gauging the mud tanks such as a tank ullage method or level
indicating devices may be fitted in lieu of sounding pipe per 4-4-3/13.3.

146 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Chapter 5: Fire Extinguishing Systems

4
CHAPTER 5 Fire Extinguishing Systems

CONTENTS
SECTION 1 All Vessels .......................................................................................... 150
1 General ...........................................................................................150
1.1 Classification Requirements ........................................................ 150
1.3 Governmental Authority............................................................... 150
1.5 Automated Propulsion Machinery Spaces................................... 150
1.7 Plans and Specifications ............................................................. 150
1.9 Fire Control Plans........................................................................ 150
1.11 Additional Fixed Fire Fighting Systems ....................................... 150
3 Fire Pumps, Fire Main, Hydrants and Hoses..................................151
3.1 Materials...................................................................................... 151
3.3 Fire Pumps .................................................................................. 151
3.5 Fire Main ..................................................................................... 151
3.7 Hydrants ...................................................................................... 151
3.9 Hoses .......................................................................................... 152
3.11 Nozzles........................................................................................ 152
5 Means for Closing of Openings, Stopping of Machinery and Oil
Containment....................................................................................153
5.1 Ventilation Fans and Openings ................................................... 153
5.3 Other Auxiliaries .......................................................................... 153
5.5 Oil Tank Suction Pipes ................................................................ 153
7 Helicopter Facilities.........................................................................153
7.1 Application................................................................................... 153
7.3 Provisions for Helicopter Deck .................................................... 153
7.5 Provisions for Enclosed Helicopter Facilities ............................... 154
7.7 Operation Manual........................................................................ 154
9 Portable Extinguishers ....................................................................154
11 Paint and Flammable Liquid Lockers..............................................155
11.1 Lockers of 4 m2 (43 ft2) or More Floor Area and Lockers with
Access to Accommodation Spaces ............................................. 155
2 2
11.3 Lockers of Less Than 4 m (43 ft ) Floor Area Having no
Access to Accommodation Spaces ............................................. 155

TABLE 1 Classification of Portable and Semi-portable

Extinguishers.........................................................................156
TABLE 2 Portable and Semi-portable Extinguishers ...........................156

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 147
 SECTION 2 Requirements for Vessels 500 Gross Tons and Over ..................... 157
1 Fire Safety Measures......................................................................157
3 Size of Fire Main .............................................................................157
5 Main and Emergency Fire Pumps ..................................................157
5.1 Main Fire Pumps..........................................................................157
5.3 Emergency Fire Pumps ...............................................................158
7 International Shore Connection ......................................................159
9 Machinery Spaces ..........................................................................160
9.1 Fixed Local Application Firefighting Systems ..............................160
9.3 Segregation of Purifiers for Heated Fuel Oil ................................160
11 Fixed Fire Extinguishing Systems...................................................161
11.1 Gas Smothering...........................................................................161
11.3 Carbon Dioxide Systems .............................................................161
11.5 Foam ...........................................................................................162
11.7 Fixed Water Spraying Systems ...................................................162
13 Additional Requirements for Vessels of 500 Gross Tons and
Over Engaged in International Voyages .........................................162
15 Fireman’s Outfit...............................................................................162
16 Emergency Escape Breathing Devices (EEBDs) ...........................162
16.1 Accommodation Spaces ..............................................................162
16.3 Machinery Spaces .......................................................................162
17 Portable Fire Extinguishers.............................................................163
19 Portable Foam Applicator Units ......................................................163
19.1 Specification ................................................................................163
19.3 System Performance ...................................................................163
21 Fire Detection and Fire Alarm Systems ..........................................164
23 Sample Extraction Smoke Detection Systems ...............................164
25 Accommodation and Service Spaces .............................................164
25.1 Fixed Systems .............................................................................164
25.3 Portable Fire Extinguishers..........................................................164
27 Fixed Fire Extinguishing Arrangements in way of Cargo
Spaces ............................................................................................164
27.1 Cargo Vessels of 2000 Gross Tons and Over .............................164
27.3 Exceptions ...................................................................................164
27.5 Controls .......................................................................................164
29 Ro-Ro Cargo Spaces......................................................................164
29.1 Fire Detection ..............................................................................164
29.3 Fire Extinguishing Arrangements.................................................165
29.5 Portable Fire Extinguishers..........................................................165
29.7 Ro-Ro Spaces Carrying Motor Vehicles with Fuel in Their
Tanks...........................................................................................165
31 Cargo Spaces Carrying Vehicles with Fuel in Their Tanks
(Other Than Ro-Ro Spaces) ...........................................................165
33 Additional Requirements for Vessels Intended to Carry Oil
in Bulk .............................................................................................165
33.1 Fixed Fire Extinguishing Systems................................................165
33.3 Fire Main Isolation Valves............................................................166

148 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 33.5 Gas Detectors ............................................................................. 166
33.7 Fireman’s Outfits ......................................................................... 166
35 Chemical and Gas Carriers.............................................................166
37 Release of Smoke from Machinery Space .....................................166

TABLE 1 Minimum Number of Required EEBDs .................................163

FIGURE 1 International Shore Connection ............................................159

SECTION 3 Requirements for Vessels Under 500 Gross Tons .......................... 167
1 Fire Pumps......................................................................................167
1.1 Number of Pumps ....................................................................... 167
1.3 Capacity ...................................................................................... 167
3 Fixed Fire Extinguishing Systems...................................................167
3.1 Fixed Systems............................................................................. 167
3.3 Portable Extinguishers ................................................................ 167
5 Carbon Dioxide Systems ................................................................167
5.1 Storage........................................................................................ 167
7 Axe ..................................................................................................168
9 Vessels Intended to Carry Oil in Bulk .............................................168
9.1 Cargo Pump Rooms .................................................................... 168
9.3 Cargo Tank Protection................................................................. 168

TABLE 1 Fire Pump Minimum Capacity for Vessels Less Than

500 Gross Tons.....................................................................168

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 149
PART Section 1: All Vessels

4
CHAPTER 5 Fire Extinguishing Systems

SECTION 1 All Vessels

1 General

1.1 Classification Requirements

The following are the minimum classification requirements for all self-propelled oceangoing vessels under
90 meters (295 feet) in length. For vessels classed with restricted service, the requirements may be modified
and the proposed fire extinguishing arrangements are to be submitted for consideration.

1.3 Governmental Authority

Attention is directed to the appropriate governmental authority. In each case, there may be additional
requirements depending on the gross tonnage, length, type and intended service of the vessel, as well as other
particulars and details. Consideration will be given to fire extinguishing systems which comply with the
published requirements of the governmental authority of the country in which the vessel is to be registered.

1.5 Automated Propulsion Machinery Spaces

Where automatic controls for propulsion machinery spaces are installed and it is intended that the propulsion
machinery spaces are either not continuously manned at sea or only one person is required on watch, the
requirements of Part 4, Chapter 7 are to be met.

1.7 Plans and Specifications

The plans together with supporting data and particulars listed in 4-1-1/7 are to be submitted for review.

1.9 Fire Control Plans

1.9.1 Required Information
Fire control plans are to be general arrangement plans showing for each deck the provision, location,
controls and particulars, as applicable, of fixed fire detection, alarm and extinguishing systems,
portable fire fighting appliances and equipment, controls for shutdowns of the ventilation system,
fuel oil pumps and valves, along with details of the means provided for the closing of openings,
and locations of accesses to critical spaces (such as fire control stations, Category A machinery
spaces, etc.). For vessels where structural fire protection is required by the Rules, locations and
type of fire retarding bulkheads are to be specified on the plan.
1.9.2 Plan Location
The fire control plans are to be conspicuously posted in the vessel for the guidance of the crew.

1.11 Additional Fixed Fire Fighting Systems (2009)

Where a fixed fire extinguishing system not required by Sections 4-5-2 and 4-5-3 is installed, such system
is to meet the applicable requirements of 4-5-2/11 and is to be submitted for approval.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 1 All Vessels 4-5-1

3 Fire Pumps, Fire Main, Hydrants and Hoses

3.1 Materials
Materials readily rendered ineffective by heat are not to be used for fire mains unless adequately protected.
In order to be considered not “readily rendered ineffective by heat”, a component is to be certified as having
passed an applicable, recognized fire test, or the material is to have a melting temperature higher than the
test temperature specified in an applicable fire test.

3.3 Fire Pumps

3.3.1 Number of Pumps
All vessels are to have at least two fire pumps. Refer to 4-5-2/5 for vessels of 500 gross tons or over,
or 4-5-3/1 for vessels under 500 gross tons.
3.3.2 Type of Pumps
Sanitary, ballast, bilge or general service pumps may be accepted as fire pumps, provided that they
are not normally used for pumping oil. If the pumps are subject to occasional duty for the transfer
or pumping of fuel oil, changeover arrangements that prevent operation for fire fighting when
configured for fuel transfer are to be fitted.
3.3.3 Pressure
Power-driven fire pumps are to have sufficient pressure to produce 12 m (40 ft) jet throw through
any two adjacent hydrants located in accordance with 4-5-1/3.7.1. Also refer to 4-5-2/5.1 or 4-5-3/1.
3.3.4 Relief Valves
In conjunction with all fire pumps, relief valves are to be provided if the pumps are capable of
developing a pressure exceeding the design pressure of the water service pipes, hydrants and hoses.
These valves are to be so placed and adjusted as to prevent excessive pressure in any part of the fire
main system. In general, the relief valve is to be set to relieve at no greater than 1.7 bar (1.75 kgf/cm2,
25 psi) in excess of the pump pressure necessary to maintain the requirements of 4-5-1/3.3.3.

3.5 Fire Main

3.5.1 Size
Refer to 4-5-2/3 for vessels of 500 gross tons and over. For vessels under 500 gross tons, the diameter
of the fire main and water service pipes is to be sufficient for the effective distribution of the maximum
required discharge from the pump(s). Refer to 4-5-3/1 and 4-5-3/Table 1.
3.5.2 Cocks or Valve
A valve is to be fitted to serve each fire hose so that any fire hose may be removed while the fire
pumps are at work.
3.5.3 Cold Weather Protection
Fire main systems are to be provided with drains, circulation loops or other means for cold weather
protection.

3.7 Hydrants
3.7.1 Number and Position of Hydrants
The number and position of the hydrants are to be such that at least two jets of water not emanating
from the same hydrant, one of which is to be from a single length of hose, may reach any part of
the vessel normally accessible to the passengers or crew while the vessel is being navigated. In
addition, the arrangements are to be such that at least two jets of water can reach any part of any
cargo space when empty.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 1 All Vessels 4-5-1

3.7.2 Materials
Materials readily rendered ineffective by heat are not be used for fire protection systems unless
adequately protected. See 4-5-1/3.1.
3.7.3 Installation
The pipes and hydrants are to be so placed that the fire hoses may be easily coupled to them. In
vessels where deck cargo may be carried, the positions of the hydrants are to be such that they are
always readily accessible and the pipes are to be arranged to avoid risk of damage by such cargo.

3.9 Hoses (2009)

3.9.1 General
Fire hoses are to be of a type certified by a competent independent testing laboratory as being
constructed of nonperishable material to a recognized standard. The hoses are to be sufficient in
length to project a jet of water to any of the spaces in which they may be required to be used.
Fire hoses are to have a length of at least 10 m (33 ft), but not more than:
• 15 m (50 ft) in machinery spaces;
• 20 m (66 ft) in other spaces and open decks; and
• 25 m (82 ft) for open deck on vessels with a maximum breath in excess of 30 m (98 ft)
Each hose is to have a nozzle and the necessary couplings. Fire hoses, together with any necessary
fittings and tools, are to be kept ready for use in conspicuous positions near the hydrants.
3.9.2 Diameter
For vessels less than 500 gross tons, hoses are not to have a diameter greater than 38 mm (1.5 in.).
Hoses for vessels under 20 m (65 ft) in length may be of a good commercial grade having a diameter
of not less than 16 mm (5/8 in.), and are to be have a minimum test pressure of 10.3 bar (10.5 kgf/cm2,
150 psi) and a minimum burst pressure of 31.0 bar (31.6 kgf/cm2, 450 psi).
3.9.3 Number of Fire Hoses
In vessels of 1,000 gross tonnage and upwards, the number of fire hoses to be provided is to be at
least one for each 30 m (100 ft) length of the vessel and one spare, but in no case less than five in
all. This number does not include any hoses required in any engine or boiler room.
In vessels of less than 1,000 gross tonnage, the number of fire hoses to be provided is to be at least
one for each 30 m (100 ft) length of the vessel and one spare. However, the number of hoses is to
be in no case less than three.
Unless one hose and nozzle is provided for each hydrant in the vessel, there are to be complete
interchangeability of hose couplings and nozzles.

3.11 Nozzles
3.11.1 Size
Standard nozzle sizes are to be 12 mm (0.5 in.), 16 mm (0.625 in.) and 19 mm (0.75 in.), or as near
thereto as possible. Larger diameter nozzles may be permitted subject to compliance with 4-5-1/3.3.3.
For accommodation and service spaces, a nozzle size greater than 12 mm (0.5 in.) need not be
used. For machinery spaces and exterior locations, the nozzle size is to be such as to obtain the
maximum discharge possible from two jets at the pressure mentioned in 4-5-1/3.3.3 from the
smallest pump; however, a nozzle size greater than 19 mm (0.75 in.) need not be used.
3.11.2 Type
All nozzles are to be of an approved dual-purpose type (i.e., spray and jet type) incorporating a
shut-off. Fire hose nozzles of plastic type material such as polycarbonate may be accepted subject
to review of their capacity and serviceability as marine use fire hose nozzles.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 1 All Vessels 4-5-1

5 Means for Closing of Openings, Stopping of Machinery and Oil

Containment

5.1 Ventilation Fans and Openings

Means are to be provided for stopping ventilation fans serving machinery and cargo spaces, and for closing
all doorways, ventilators and other openings to such spaces. These means are to be capable of being
operated from outside such spaces in case of fire. See 4-6-2/19.1.1.

5.3 Other Auxiliaries (2009)

Machinery driving forced- and induced-draft fans, oil-fuel transfer pumps, oil-fuel unit pumps and other
similar fuel pumps, fired equipment such as an incinerator, lubricating oil service pumps, thermal oil circulating
pumps and oil separators (purifiers) are to be fitted with remote shutdowns situated outside of the spaces
concerned so that they may be stopped in the event of a fire arising in the space. This need not apply to
oily water separators. See 4-6-2/19.1.2.
In addition to the remote shutdowns required above, a means to shutdown the equipment is to be provided
within the space itself.

5.5 Oil Tank Suction Pipes (1998)

Except for small independent tanks having a capacity of less than 500 liters (132 gal.), every oil-suction
pipe from a storage, settling, daily service tank or lube oil tank situated above the double bottom is to be
fitted with a valve capable of being closed in the event of a fire from outside of the space where such tanks
are located. In the special case of deep tanks situated in any shaft or pipe tunnel, control may be effected
by means of an additional valve on the pipe line outside of the tunnel. See 4-4-4/3.7.
Where inadvertent valve closure could result in damage to the running machinery due to lack of lubricating
oil, a valve is to be fitted on the lubricating oil tank, but remote control of the valve from outside of the
space is not required. See 4-4-4/1.1.

7 Helicopter Facilities (2005)

7.1 Application
For each helicopter deck on board a vessel designated for helicopter operations, fire fighting system and
equipment complying with 4-5-1/7.3.2 and 4-5-1/7.3.3 as applicable, are to be provided.
Helicopter deck (helideck) is a purpose-built helicopter landing area, on a vessel including all structure,
fire fighting appliances and other equipment necessary for the safe operation of helicopters, but not those
areas for occasional or emergency helicopter operations (e.g., circle H marked on hatch covers for drop-
off/pickup of pilot). Helicopter facility is a helideck including any refueling and hangar facility.

7.3 Provisions for Helicopter Deck

7.3.1 Hoses and Nozzles
At least two combination solid stream and water spray nozzles and hoses sufficient in length to reach
any part of the helicopter deck are to be provided.
7.3.2 Portable Extinguishers
The helicopter deck is to be protected by at least two dry powder extinguishers of a total capacity
of not less than 45 kg (100 lb).
7.3.3 Back-up System
A back-up fire fighting system is to be provided consisting of CO2 extinguishers of a total capacity
of not less than 18 kg (40 lb) or equivalent, one of these extinguishers being equipped so as to
enable it to reach the engine area of any helicopter using the helicopter deck. The back-up system
is to be located so that the equipment would not be vulnerable to the same damage as the dry
powder extinguisher required by 4-5-1/7.3.2.

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Chapter 5 Fire Extinguishing Systems
Section 1 All Vessels 4-5-1

7.3.4 Fixed Foam System

A suitable fixed foam fire extinguishing system, consisting of monitors or hose streams or both, is
to be installed to protect the helicopter landing area in all weather conditions in which helicopters
can operate. The system is to be capable of delivering foam solution at a discharge rate in accordance
with the following table for at least five minutes. The operation of the foam system is not to interfere
with the simultaneous operation of the fire main.

Category Helicopter Overall Length, LH Discharge Rate

Liters/min. gpm
H1 LH < 15 m (49 ft) 250 66
H2 15 m (49 ft) ≤ LH < 24 m (79 ft) 500 132
H3 24 m (79 ft) ≤ LH < 35 m (115 ft) 800 211

The foam agent is to meet the performance standards for Level B foam in the International Civil
Aviation Organization’s Airport Services Manual (Part 1 Chapter 8, Paragraph 8.1.5, Table 8-1)
and be suitable for use with sea water.
7.3.5 Fireman’s Outfits
In addition to the fireman’s outfits required in 4-5-2/15, two additional sets of fireman’s outfits are
to be provided and stored near the helicopter deck.
7.3.6 Other Equipment
The following equipment is to be provided near the helicopter deck and is to be stored in a manner
that provides for immediate use and protection from the elements:
• Adjustable wrench
• Fire resistant blanket
• Bolt cutters with arm length of 60 cm (24 in.) or more
• Grab hook or salving hook
• Heavy duty hack saw, complete with six spare blades
• Ladder
• Lifeline of 5 mm (3/16 in.) diameter × 15 m (50 ft) length
• Side cutting pliers
• Set of assorted screw drivers
• Harness knife complete with sheath

7.5 Provisions for Enclosed Helicopter Facilities

Hangars, refueling and maintenance facilities are to be treated as machinery space of category A with
regard to structural fire protection, fixed fire-extinguishing system and fire detection system requirements.
See 4-5-2/11and 4-5-2/21.

7.7 Operation Manual

Each helicopter facility is to have an operation manual, including a description and a checklist of safety
precautions, procedures and equipment requirements. This manual may be part of the vessel’s emergency
response procedures.

9 Portable Extinguishers
Portable extinguishers are to be provided in the quantities and locations indicated in 4-5-1/Table 1 and
4-5-1/Table 2.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 1 All Vessels 4-5-1

11 Paint and Flammable Liquid Lockers (2001)

Paint and flammable liquid lockers or any similar service spaces used for the storage of flammable liquids
(such as solvents, adhesives, lubricants etc.) are to be protected by a fire extinguishing arrangement enabling
the crew to extinguish a fire without entering the space. Unless required or permitted otherwise by the flag
Administration, one of the following systems is to be provided:

11.1 Lockers of 4 m2 (43 ft2) or More Floor Area and Lockers with Access to Accommodation
Spaces
Paint lockers and flammable liquid lockers of floor area 4 m2 (43 ft2) or more and also such lockers of any
floor area with access to accommodation spaces are to be provided with one of the fixed fire extinguishing
systems specified below:
i) CO2 system, designed for 40 % of the gross volume of the space.

ii) Dry powder system, designed for at least 0.5 kg/m3 (0.03 lb/ft3).
iii) Water spraying system, designed for 5 liters/m2/minute (0.12 gpm/ft2). The water spraying system
may be connected to the vessel’s fire main system, in which case, the fire pump capacity is to be
sufficient for simultaneous operation of the fire main system, as required in 4-5-2/5.1, and the water
spray system. Precautions are to be taken to prevent the nozzles from being clogged by impurities
in the water or corrosion of piping, nozzles, valves and pump.
iv) Systems or arrangements other than those referenced above may be also considered, provided they
are not less effective.

11.3 Lockers of Less Than 4 m2 (43 ft2) Floor Area Having no Access to Accommodation
Spaces
For paint lockers and flammable liquid lockers of floor area less than 4 m2 (43 ft2) having no access to
accommodation spaces, portable fire extinguisher(s) sized in accordance with 4-5-1/11.1i) and which can
be discharged through a port in the boundary of the lockers may be accepted. The required portable fire
extinguishers are to be stowed adjacent to the port. Alternatively, a port or hose connection may be
provided for this purpose to facilitate the use of water from the fire main.

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Section 1 All Vessels 4-5-1

TABLE 1
Classification of Portable and Semi-portable Extinguishers (1 July 2009)
Fire extinguishers are designated by type as follows: A, for fires in combustible materials such as wood; B, for fires in
flammable liquids and greases; C, for fires in electrical equipment.
Fire extinguishers are designated by size where I is the smallest. Sizes I and II are hand portable extinguishers and sizes III
and V are semi-portable extinguishers.

Classification Water Foam Carbon Dioxide Dry Chemical

Type Size liters (US gallons) liters (US gallons) kg (lb) kg (lb)
A II 9 (2.5) 9 (2.5) — 5 (11) (1)
B II — 9 (2.5) 5 (11) 5 (11)
B III — 45 (12) 15.8 (35) 9 (20)
B V — 152 (40) 45 (100) (2) 22.5 (50) (2)
C I — — 1.8 (4) 0.9 (2)
C II — — 5 (11) 5 (11)
Notes:
1 Must be specifically approved as Type A, B, C extinguisher
2 For outside use, double the amount to be carried.

TABLE 2
Portable and Semi-portable Extinguishers (1 July 2009)
Space Classification Quantity and Location (5)
Safety Areas
Communicating corridors A-II 1 in each main corridor not more than 46 m (150 ft) apart. (May be located in
stairways.)
Pilothouse (1 July 2009) C-II 2 in vicinity of exit. See Notes 4 and 6.
Radio room C-II 1 in vicinity of exit. See Note 4.
Accommodations
Sleeping Accommodations A-II 1 in each sleeping accommodation space. (Where occupied by more than four
persons.)
Service Spaces
Galleys B-II or C-II 1 for each 230 m2 (2500 ft2) or fraction thereof for hazards involved.
Storerooms A-II 1 for each 230m2 (2500 ft2) or fraction thereof located in vicinity of exits,
either inside or outside of spaces. See Note 4.
Workshops A-II 1 outside the space in vicinity of exit. See Note 4.
Machinery Spaces
Internal combustion or gas B-II 1 for each 746 kW (1000 hp), but not less than 2 nor more than 6. See Note 1.
turbine-engines and B-III 1 required. See Note 3.
Electric motors or generators C-II 1 for each motor or generator unit. See Note 2.
of the open type
Notes:
1 When installation is on weather deck or open to atmosphere at all times, one B-II for every three engines is allowable.
2 Small electrical appliances, such as fans, etc., are not to be counted or used as basis for determining number of
extinguishers required.
3 Not required on vessels of less than 500 gross tons.
4 Vicinity is intended to mean within 1 m (3 ft).
5 For vessels of 1000 gross tons and above, at least five extinguishers are to be provided for accommodation spaces,
service spaces, spaces where the vessel’s radio, main navigation equipment or emergency source of power is
located, and locations where the fire recording or fire control equipment is located.
6 (1 July 2009) For cargo ships less than 500 gross tons, “C-I” portable extinguishers may be used.

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PART Section 2: Requirements for Vessels 500 Gross Tons and Over

4
CHAPTER 5 Fire Extinguishing Systems

SECTION 2 Requirements for Vessels 500 Gross Tons and

Over

1 Fire Safety Measures

The applicable requirements of Section 3-4-1 are to be complied with.

3 Size of Fire Main

The diameter of the fire main and water service pipes is to be sufficient for the effective distribution of the
maximum required discharge from two fire pumps operating simultaneously, except that the diameter need
only be sufficient for the discharge of 140 m3/hr (616 gpm).

5 Main and Emergency Fire Pumps

5.1 Main Fire Pumps

5.1.1 Number of Pumps
For vessels of 1000 gross tons and above, the pumps are to be independently power-driven. For
vessels less than 1000 gross tons, only one of the pumps need be independently power-driven and
one of the pumps may be attached to the propulsion unit.
5.1.2 Total Pump Capacity
The fire pumps required by 4-5-2/5.1.1 are to be capable of delivering for firefighting purposes a
quantity of water, at the appropriate pressure prescribed, not less than four-thirds of the quantity
required under 4-4-3/3.3 to be dealt with by each of the independent bilge pumps when employed
on bilge pumping, using in all cases L = length of vessel, as defined in 3-1-1/3, except that the
total required capacity of the fire pumps need not exceed 180 m3/hr (792 gpm).
5.1.3 Individual Pump Capacity
Each of the fire pumps required by 4-5-2/5.1.1 is to have a capacity of not less than 40% of the
total required capacity, but not less than 25 m3/hr (110 gpm), and in any event is to be capable of
delivering at least the two required jets of water. These pumps are to be capable of supplying the
water under the required conditions. Where more pumps than required are installed, their capacity
will be subject to special consideration.
5.1.4 Pressure
For vessels 1000 gross tons and over with the two power-driven pumps simultaneously delivering
through the nozzles specified in 4-5-1/3.11 the quantity of water specified in 4-5-1/3.5.1 through
any adjacent hydrants, a pressure of 2.5 bar (2.6 kgf/cm2, 37 psi) is to be maintained at all hydrants.
For vessels less than 1000 gross tons, the power-driven fire pumps are to have sufficient pressure
to produce 12 m (40 ft) jet throw through any two adjacent hydrants located in accordance with
4-5-1/3.5.1.

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Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

5.1.5 Arrangement
Unless an emergency fire pump complying with 4-5-2/5.3 is provided, the two main fire pumps,
including their power source, fuel supply, electric cables, and lighting and ventilation for the spaces
in which they are located, are to be in separate compartments so that a fire in any one compartment
will not render both main pumps inoperable. Only one common boundary is allowed between the
compartments, in which case, the single common boundary is to be at least to A-0 standard.
No direct access is allowed between the compartments except that where this is impracticable, an
access meeting the requirements in 4-5-2/5.1.6 may be considered.
5.1.6 Alternative Arrangement
Where it is impracticable to do otherwise, a direct access between the compartments containing
the main fire pumps may be considered, provided:
i) A watertight door capable of being operated locally from both sides of the bulkhead, and
from a safe and accessible location outside of these spaces is provided. The means for the
latter operation is expected to be available in the event of fire in these spaces; or
ii) An air lock consisting of two gastight steel doors. The doors are to be self-closing without
any hold back arrangements.
iii) In addition to the arrangements specified in 4-5-2/5.1.6i) or 4-5-2/5.1.6ii) above, a second
protected means of access is to be provided to the space containing the fire pumps.
5.1.7 Isolation
Isolating valves and other arrangements, as necessary, are to be provided so that if a fire pump and
its associated piping within its compartment are rendered inoperable, the fire main can be pressurized
with a fire pump located in another compartment.

5.3 Emergency Fire Pumps

5.3.1 When Required
If a fire in any one compartment could put all main pumps out of action (see 4-5-2/5.1.2), an
independently power-driven and self-priming emergency fire pump complying with this paragraph
is to be provided.
5.3.2 Arrangement
An emergency fire pump system, including power source, fuel supply, electric cables, and lighting,
as well as lighting and ventilation for the emergency fire pump space, is to be in a separate
compartment than the main fire pumps so that a fire in any one compartment will not render both
the main and the emergency fire pumps inoperable.
No direct access is permitted between the main machinery space and the spaces containing the
emergency fire pump and its source of power. Where this is impracticable, access between the space
containing the emergency fire pump and the main machinery space, in accordance with 4-5-2/5.1.6,
may be considered
The space containing the emergency fire pump is not to be contiguous to the boundaries of machinery
spaces of Category A or the spaces containing the main fire pumps. Where this is impracticable,
the common bulkhead between the two spaces is to be constructed to A-60 standard. The insulation
is to extend at least 450 mm (18 in.) outside of the area of the joint bulkheads and decks.
5.3.3 Capacity
The emergency fire pump is to be capable of supplying at least two jets of water required by
4-5-1/3.5.1, using the available hydrants, hoses and nozzles, and is to have a capacity of at least 40%
of the total capacity of the fire pumps required by 4-5-2/5.1.2 or 25 m3/hr (110 gpm), whichever is
greater.
When the pump is delivering the quantity of water, as above, the pressure at the hydrant is to be
not less than the pressure given in 4-5-2/5.1.4.
In addition, the emergency fire pump is also to be capable of simultaneously supplying the amount
of water needed for any fixed extinguishing system protecting the space containing the main pumps.

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Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

5.3.4 Starting
Internal combustion engines larger than 15 kW (20 hp) are to be provided with power starting systems
having a capacity sufficient for at least six starts within 30 minutes, including at least two within
the first ten minutes. For engines of 15 kW (20 hp) and smaller, manual means of starting is sufficient.
Any internal combustion engine driving an emergency fire pump is to be capable of readily being
started in its cold condition down to a temperature of 0°C (32°F). If this is impracticable or if
lower temperatures are likely to be encountered, consideration is to be given to the provision and
maintenance of heating arrangements.
5.3.5 Fuel Supply
Any service fuel tank is to contain sufficient fuel to enable the pump to run on full load for at least
three hours and sufficient reserves of fuel are to be available outside of the main machinery space
to enable the pump to be run on full load for an additional 15 hours.
5.3.6 Suction
The total suction head and the net positive suction head of the pump is to be such that the
requirements of 4-5-2/5.3.3 and 4-5-2/5.1.4 will be satisfied under all conditions of list, trim, roll
and pitch likely to be encountered in service. The sea valve is to be operable from a position near
the pump or locked in the open position (provided possible flooding can be detected).

7 International Shore Connection

At least one international shore connection, as shown in 4-5-2/Figure 1, is to be provided and kept aboard
the vessel with gasket, bolts and eight washers. Facilities are to be available enabling such a connection to
be used on either side of the vessel.

FIGURE 1
International Shore Connection
Coupling permanently attached that will
fit the vessel's hydrants and hose.
14.5 mm (9/16 in.)min.

Flat Face

64 mm
(21/2 in.)
132 mm
(51/4 in.)

178 mm
(7 in.)

19 mm
(3/4 in.)

Bolts: 4, each of 16 mm ( 5/8 in.) diameter, 50 mm (2 in.) in length

Flange Surface: Flat face
Material: Any suited for 10 bar (10.5 kgf/cm 2, 150 psi)
Gasket: Any suited for 10 bar (10.5 kgf/cm 2, 150 psi) service

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Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

9 Machinery Spaces
Category A machinery spaces are to be protected by a fixed fire extinguishing system complying with 4-5-2/11.

9.1 Fixed Local Application Firefighting Systems (1 July 2002)

For cargo vessels of 2000 gross tonnage and above, the machinery spaces of category A above 500 m3
(17,657 ft3) in volume, in addition to the fixed fire extinguishing system required in 4-5-2/11, are to be
protected by an approved type of fixed water-based or equivalent local application firefighting system
complying with the provisions of the IMO Guidelines for the Approval of Fixed Water-based Local
Application Firefighting System for Use in Category A Machinery Spaces, MSC/Circ. 913. In the case of
periodically unattended machinery spaces, the fire fighting system is to have both automatic and manual
release capabilities. In case of continuously manned machinery spaces, the fire fighting system is only
required to have a manual release capability. The fixed local fire fighting systems are to protect areas such
as the following without the necessity of engine shutdown, personnel evacuation or sealing the spaces:
i) The fire hazard portion of internal combustion machinery used for the vessel’s main propulsion
and power generation and, if provided;
ii) Purifiers for heated fuel oil, see 4-5-2/9.3;
iii) The fire hazard portions of incinerators; and
iv) Boiler front.
Activation of any local application system shall give a visual and distinct audible alarm in the protected
space and at continuously manned stations. The alarm is to indicate the specific system activated. The
system alarm requirements described within this paragraph are in addition to, and not a substitute for, the
detection and fire alarm system required elsewhere in Section 4-5-2 and Section 4-5-3.

9.3 Segregation of Purifiers for Heated Fuel Oil (1 July 2002)

Fuel oil purifiers for heated oil are to be placed in separate room or rooms enclosed by steel bulkheads
extending from deck to deck and provided with self-closing doors. In addition, the room is to be provided
with the following:
i) Independent mechanical ventilation or ventilation arrangement that can be isolated from the
machinery space ventilation, of the suction type.
ii) Fire detection system.
iii) Fixed fire extinguishing system capable of activation from outside of the room. The extinguishing
system is to be dedicated to the room, but may be a part of the fixed fire extinguishing system for
the machinery space.
However, for the protection of purifiers on cargo vessels of 2000 gross tonnage and above located
within a machinery space of category A above 500 m3 (17,657 ft3) in volume, the above referenced
fixed, dedicated system is to be a fixed, water-based or equivalent, local application fire extinguishing
system complying with the provisions of 4-5-2/9.1. The system is to be capable of activation from
outside of the purifier room. In addition, protection is to be provided by the fixed fire extinguishing
system covering the Category A machinery space in which the purifier room is located. See 4-5-2/11.
iv) Means of closing ventilation openings and stopping the ventilation fans, purifiers, purifier-feed
pumps, etc., from a position close to where the fire extinguishing system is activated.
If it is impracticable to locate the fuel oil purifiers in a separate room, special consideration will be given
with regard to location, containment of possible leakage, shielding and ventilation. In such cases, a local,
fixed water-based fire extinguishing system complying with the provisions of 4-5-2/9.1 is to be provided.
Where, due to the limited size of the category A machinery space, a local fixed water-based fire-extinguishing
system is not provided, then an alternative type of local, dedicated, fixed fire extinguishing system is to be
provided for the protection of the purifiers. In either case, the local fire extinguishing system is to activate
automatically or manually from the centralized control station or other suitable location. If automatic release
is provided, additional manual release is also to be arranged.

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Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

11 Fixed Fire Extinguishing Systems

11.1 Gas Smothering

11.1.1 Storage (1 July 2007)
Where the gas smothering medium is stored outside of the protected space, the storeroom is to be
situated in a safe and readily accessible position and is to be effectively ventilated by a ventilation
system independent of all other spaces.
Spaces for storage of cylinders or tanks for extinguishing gas should not be used for other purposes.
These spaces should not be located forward of the forward collision bulkhead. Access to these
spaces should be possible from the open deck. Spaces situated below the deck should be located
no more than one deck below the open deck.
Spaces where entrance from the open deck are not provided or which are located below deck are
to be fitted with mechanical ventilation. The exhaust duct (suction) should be lead to the bottom of
the space. Such spaces should be ventilated with at least six air changes per hour.
Fire-extinguishing media protecting the cargo holds (see 4-5-2/27) may be stored in a room located
forward of the cargo holds, but aft of the collision bulkhead, provided that both the local manual
release mechanism and remote control(s) for the release of the media are fitted, and the latter is of
robust construction or so protected as to remain operable in case of fire in the protected spaces.
The remote controls are to be placed in the accommodation area in order to facilitate their ready
accessibility by the crew. The capability to release different quantities of fire-extinguishing media
into different cargo holds so protected is to be included in the remote release arrangement.
11.1.2 Design
Containers and associated pressure components are to be designed based upon an ambient temperature
of 55°C (131°F).
11.1.3 Alarm
Means are to be provided for automatically giving audible warning of the release of fire extinguishing
gas into any space to which personnel normally have access. The alarm is to operate for at least a
20 second period before the gas is released. Alarms may be pneumatically (by the extinguishing
medium or by air) or electrically operated.
11.1.3(a) Electric. If electrically operated, the alarms are to be supplied with power from the
main and an emergency source of electrical power.
11.1.3(b) Pneumatic. If pneumatically operated by air, the air supply is to be dry and clean and
the supply reservoir is to be automatically kept charged at all times and is to be fitted with a low
pressure alarm. The air supply may be taken from the starting air receivers. Any stop valve fitted
in the air supply line is to be locked or sealed in the open position. Any electrical components
associated with the pneumatic system are to be powered from the main and an emergency source
of electrical power.
11.1.4 Controls
Except as otherwise permitted herein, two independent manual control arrangements are to be
provided, one of them being positioned at the storage location and the other in a readily accessible
position outside the protected space.

11.3 Carbon Dioxide Systems

In addition to the applicable requirements of the Rules, fixed carbon dioxide fire extinguishing systems are
to be in accordance with Chapter II-2, Regulations 10.4.2 and 10.4.3 of the International Convention for
the Safety of Life at Sea (SOLAS) 1974 and Amendments in force, and Chapter 1.4 and Chapter 5 of the
International Code for Fire Safety Systems. Fixed, low pressure carbon-dioxide systems are to be in
accordance with 4-7-3/3.5 of the Steel Vessel Rules.

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Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

11.5 Foam (1998)

11.5.1 Fixed High Expansion Foam Systems (1 July 2009)
In addition to the applicable requirements of the Rules, fixed, high expansion foam systems are to be in
accordance with Chapter 6.2.1 and Chapter 6.2.2 of the International Code for Fire Safety Systems.
Fixed foam fire-extinguishing systems using inside air are to be designed, constructed and tested
in accordance with the requirements identified in MSC.1/Circ. 1271, Guidelines for the Approval
of High-Expansion Foam Systems Using Inside Air for the Protection of Machinery Spaces and
Cargo Pump-Rooms.
Foam concentrates are to be of an approved type.*
*Note: Reference is made to the International Maritime Organization MSC/Circular 670 “Guidelines for the
Performance and Testing Criteria, and Surveys of High-Expansion Foam Concentrates for Fixed Fire-
Extinguishing Systems.”

11.5.2 Fixed Low Expansion Foam Systems

Low expansion foam systems may be fitted in addition to the required fixed fire extinguishing system.
In addition to the applicable requirements of the Rules, fixed low expansion foam systems are to
be in accordance with Chapter 6.2.1 and Chapter 6.2.3 of the International Code for Fire Safety
Systems. Foam concentrates are to be of an approved type.**
**Note: Reference is made to the International Maritime Organization MSC/Circular 582 “Guidelines for the
Performance and Testing Criteria, and Surveys of Low-Expansion Foam Concentrates for Fixed Fire-
Extinguishing Systems.”

11.7 Fixed Water Spraying Systems

In addition to the requirements of the Rules, fixed water spraying systems are to be in accordance with
Chapter 7 of the International Code for Fire Safety Systems.

13 Additional Requirements for Vessels of 500 Gross Tons and Over

Engaged in International Voyages
Vessels of 500 gross tons and over, engaged in international voyages, are to comply with the additional
requirements in 4-5-2/15 through 4-5-2/35. These requirements need not be applied for vessels in domestic
service which do not engage in international voyages.

15 Fireman’s Outfit
At least two complete fireman’s outfits are to be carried onboard the vessel. Each outfit is to consist of an
approved breathing apparatus, a lifeline, a safety lamp, an axe, non-conducting boots and gloves, a rigid
helmet and protective clothing. At least one spare charge is to be carried for each self-contained breathing
apparatus. The fireman’s outfits and equipment are to be stored so as to be easily accessible and ready for use
and are to be stored in widely separate positions. Also see 4-5-2/33.7 for vessels intended to carry oil in bulk.

16 Emergency Escape Breathing Devices (EEBDs) (2005)

16.1 Accommodation Spaces

All ships are to carry at least two emergency escape breathing devices and one spare device within
accommodation spaces.

16.3 Machinery Spaces

On all vessels, within the machinery spaces, emergency escape breathing devices are to be situated ready
for use at easily visible places, which can be reached quickly and easily at any time in the event of fire.
The location of emergency escape breathing devices is to take into account the layout of the machinery
space and the number of persons normally working in the spaces. (See the Guidelines for the performance,
location, use and care of emergency escape breathing devices, MSC/Circ. 849 and 1081). The number and
locations of EEBDs are to be indicated in the fire control plan required in 4-5-1/1.9.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

A summary of the MSC/Circ. 1081 requirements are shown in 4-5-2/Table 1. This applies to machinery
spaces where crew are normally employed or may be present on a routine basis.

TABLE 1
Minimum Number of Required EEBDs (2005)
A. In machinery spaces for category A containing internal combustion machinery used for main
propulsion (1):
a) One (1) EEBD in the engine control room, if located within the machinery space
b) One (1) EEBD in workshop areas. If there is, however, a direct access to an escape way from the
workshop, an EEBD is not required; and
c) One (1) EEBD on each deck or platform level near the escape ladder constituting the second means of
escape from the machinery space (the other means being an enclosed escape trunk or watertight door at
the lower level of the space).
B. In machinery spaces of category A other than those containing internal combustion machinery used
for main propulsion,
One (1) EEBD should, as a minimum, be provided on each deck or platform level near the escape ladder
constituting the second means of escape from the space (the other means being an enclosed escape trunk or
watertight door at the lower level of the space).
C. In other machinery spaces
The number and location of EEBDs are to be determined by the Flag Administration.
Note:
1 Alternatively, a different number or location may be determined by the Flag Administration
taking into consideration the layout and dimensions or the normal manning of the space.

17 Portable Fire Extinguishers (2007)

Spare charges are to be provided for 100% of the first ten (10) extinguishers and 50% of the remaining fire
extinguishers capable of being recharged on board. Not more than sixty (60) total spare charges are required.
Instructions for recharging are to be carried on board.
For fire extinguishers which cannot be recharged on board, additional portable fire extinguishers of the
same quantity, type, capacity and number, as determined above, are to be provided in lieu of spare charges.

19 Portable Foam Applicator Units (1 July 2009)

Each Category A machinery space is to be provided with at least one portable foam applicator unit.

19.1 Specification
A portable foam applicator unit is to consist of a foam nozzle/branch pipe, either of a self-inducing type or
in combination with a separate inductor, capable of being connected to the fire main by a fire hose,
together with a portable tank containing at least 20 l (5.3 US gal.) of foam concentrate and at least one
spare tank of foam concentrate of the same capacity.

19.3 System Performance

i) The nozzle/branch pipe and inductor is to be capable of producing effective foam suitable for
extinguishing an oil fire, at a foam solution flow rate of at least 200 l/min (52.8 gpm) at the nominal
pressure in the fire main.
ii) The foam concentrate shall be approved by ABS based on guidelines in the Guidelines for the
Performance and Testing Criteria and Surveys of Low-expansion Foam Concentrates for Fixed
Fire-extinguishing Systems (MSC/Circ.582/Corr.1).

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Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

iii) The values of the foam expansion and drainage time of the foam produced by the portable foam
applicator unit is not to differ more than ±10% of that determined in 4-5-2/19.3ii).
iv) The portable foam applicator unit is to be designed to withstand clogging, ambient temperature
changes, vibration, humidity, shock, impact and corrosion normally encountered on ships.

21 Fire Detection and Fire Alarm Systems

Any required fixed fire detection and fire alarm system is to meet the requirements in Chapter 9 of the
International Code for Fire Safety Systems.

23 Sample Extraction Smoke Detection Systems

Any required fixed sample extraction smoke detection system is to meet the requirements in Chapter 10 of
the International Code for Fire Safety Systems.

25 Accommodation and Service Spaces

25.1 Fixed Systems

A fire detection and alarm system (methods IC or IIIC) or an automatic sprinkler, fire detection and fire
alarm system (method IIC) is to be installed in accommodation and service spaces, in accordance with
Regulation II-2/7.5.5 and Regulation II-2/10.6.2 of the International Convention for the Safety of Life at
Sea (SOLAS) 1974 and Amendments in force.

25.3 Portable Fire Extinguishers

Portable fire extinguishers are to be provided, as required by 4-5-1/9. However, for vessels of 1000 gross
tons and above, the total number of extinguishers for accommodation spaces, service spaces, spaces in which
the vessel’s radio or main navigation equipment or emergency source of power is located, and locations
where the fire recording or fire control equipment is located is not to be less than five.

27 Fixed Fire Extinguishing Arrangements in way of Cargo Spaces

27.1 Cargo Vessels of 2000 Gross Tons and Over

Except for cargo spaces covered by 4-5-2/29 and 4-5-2/31, cargo spaces of cargo vessels of 2000 gross tons
and above are to be provided with approved fixed fire extinguishing systems.

27.3 Exceptions
A fixed system need not be fitted in the case of cargo holds fitted with steel hatch covers, and where all
ventilators and other openings leading to the holds can be effectively closed, and the vessel is constructed
and intended solely for carrying ore, coal, grain, unseasoned timber or noncombustible cargoes.

27.5 Controls
As an alternative to providing the controls required by 4-5-2/11.1.4, a single manual means may be provided
at the storage location.

29 Ro-Ro Cargo Spaces

29.1 Fire Detection

An approved automatic fire detection and fire alarm system complying with 4-5-2/21 and the following is
to be provided. Manual call points are to be provided to activate the fire alarm from the navigation bridge
and the passageways having entrances to the ro-ro spaces. The fire alarm indicator/control panel is to be
located on the bridge or at the fire control station, if provided. When the indicator/control panel is located
at the fire control station, an additional alarm is to be provided on the navigation bridge.

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

29.3 Fire Extinguishing Arrangements

Ro-ro cargo spaces capable of being sealed are to be fitted with an approved fixed gas fire extinguishing
system. If a carbon dioxide system is fitted, the quantity of gas available is to be at least sufficient to give a
minimum volume of free gas equal to 45% of the gross volume of the largest such cargo space which is
capable of being sealed, and the arrangements are to be such as to ensure that at least two thirds of the gas
required for the relevant spaces is introduced within 10 minutes.
In lieu of the above, a fixed high expansion foam system or water spray system may be fitted subject to
special consideration. Ro-ro spaces not capable of being sealed are to be fitted with a fixed pressure water-
spraying system. The water-spraying system, drainage and pumping arrangements will be subject to special
consideration.
As an alternative to providing the controls required by 4-5-2/11.1.4, a single manual means may be provided
at the storage location.

29.5 Portable Fire Extinguishers

At least one approved portable extinguisher is to be located at each cargo space access.

29.7 Ro-Ro Spaces Carrying Motor Vehicles with Fuel in Their Tanks
29.7.1
Each ro-ro cargo space intended for the carriage of motor vehicles with fuel in their tanks for their
own propulsion is to meet the requirements of 4-6-6/5.5.
29.7.2
Gravity drainage systems are not to be led to machinery spaces or other spaces where sources of
ignition are present.
29.7.3
In addition, each space is to be provided with at least three water fog applicators and one portable
foam applicator unit complying with the provisions of 4-5-2/19, provided that at least two such
units are available on the vessel for use in such ro-ro cargo spaces.
29.7.4
Portable fire extinguishers suitable for fighting oil fires are to be provided at each vehicle deck
level in all spaces where vehicles are carried. Extinguishers are to be located not more than 20 m
(65 ft) apart on both sides of the vessel. Portable extinguishers required under 4-5-2/29.5 may be
credited in meeting this requirement.

31 Cargo Spaces Carrying Vehicles with Fuel in Their Tanks (Other

Than Ro-Ro Spaces) (1 July 2007)
Cargo spaces, other than ro-ro spaces, intended for the carriage of motor vehicles with fuel in their tanks
for their own propulsion are to comply with 4-5-2/29 with the following exceptions:
i) A sample extraction smoke detection system complying with the provisions of 4-5-2/23 may be
permitted in lieu of 4-5-2/29.1, and
ii) The provisions of 4-5-2/29.7.3 and 4-5-2/29.3.4 may be omitted

33 Additional Requirements for Vessels Intended to Carry Oil in Bulk

33.1 Fixed Fire Extinguishing Systems

33.1.1 Cargo Pump Rooms
Cargo pump rooms are to be provided with an approved fixed fire extinguishing system controlled
from the deck. See also 4-6-6/1.13.1(b).

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Part 4 Vessel Systems and Machinery
Chapter 5 Fire Extinguishing Systems
Section 2 Requirements for Vessels 500 Gross Tons and Over 4-5-2

33.1.2 Pump Room Alarms

Audible alarms to warn of the release of fire extinguishing medium into pump rooms, as required
by 4-5-2/11.1.3, may be of the pneumatic type or electric type. Air, and not CO2, is to be used in
the testing of pneumatic alarms. When electrically operated alarms are used, the arrangements are
to be such that the electric actuating mechanism is located outside of the pump room.
33.1.3 System Arrangement
When a tank smothering system is fitted, arrangements are to be provided to prevent tank gases
from entering dry spaces. When mixed cargo is to be carried, the smothering lines for the cargo oil
tanks are to be fitted with stop-check valves in order to prevent contamination of cargo from one
tank to another.
33.1.4 Cargo Tank Protection
For tankers of 30.5 m (100 ft) in length and above, a deck foam system is to be installed for the
protection of all cargo tanks. For tankers less than 30.5 m (100 ft) in length, two B-V extinguishers
(see 4-5-1/Table 1) are to be provided for the protection of the cargo tanks.

33.3 Fire Main Isolation Valves

Isolation valves are to be fitted in the fire main at the poop front in a protected position and on the tank
deck at intervals of not more than 40 m (131 ft).

33.5 Gas Detectors

Two portable gas detectors are to be provided.

33.7 Fireman’s Outfits

Two outfits, in addition to those required by 4-5-2/15, are to be provided.

35 Chemical and Gas Carriers

A fixed fire extinguishing system suitable for use with the intended cargo is to be provided in accordance
with Part 5C, Chapters 8 and 9 of the Steel Vessel Rules, as appropriate. Other special product carriers will
be subject to special considerations.

37 Release of Smoke from Machinery Space (2011)

Suitable arrangements are to be made to permit the release of smoke, in the event of fire, from the
machinery space of Category A. The normal ventilation may be acceptable for this purpose. The means of
control is to be provided for permitting the release of smoke and such control is to be located outside the
space concerned so that they will not be rendered inaccessible in the event of fire in the space they serve.
See also 4-6-3/5.17.1

166 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 3: Requirements for Vessels Under 500 Gross Tons

4
CHAPTER 5 Fire Extinguishing Systems

SECTION 3 Requirements for Vessels Under 500 Gross Tons

1 Fire Pumps

1.1 Number of Pumps

All vessels are to have at least two fire pumps. Only one of the pumps need be independently power-
driven, and one of the pumps may be attached to the propulsion unit. For vessels less than 20 m (65 ft) in
length, one power-driven pump, which may be an attached unit, and one hand operated fire pump may be
provided.

1.3 Capacity
The capacity of each power-driven fire pump is to be in accordance with the 4-5-3/Table 1. Hand pumps,
where permitted, are to have a minimum capacity of 1.1 m3/hr (5 gpm).

3 Fixed Fire Extinguishing Systems (2003)

3.1 Fixed Systems

For all vessels, fixed fire extinguishing systems are to be fitted in the machinery spaces when propulsion and
auxiliary engines with a total aggregate power of 750 kW (1000 bhp) or greater are installed (see 4-1-1/13.1)
and in any machinery space in which an oil fuel unit for heated fuel oil is installed, regardless of the total
aggregate power.

3.3 Portable Extinguishers

Machinery spaces are to be provided with portable fire extinguishers, in accordance with the applicable
requirements in 4-5-1/Table 2.

5 Carbon Dioxide Systems

Where a fixed carbon dioxide fire extinguishing system is installed, the system is to comply with the
requirements of 4-5-2/11.1 and 4-5-2/11.3, except that storage arrangements may be in accordance with the
following.

5.1 Storage
Generally, the cylinders are to be located outside of the protected space in a room which is situated in a
safe and readily accessible location. The access doors to the storage space are to open outwards. The
storage room is to be gastight and effectively ventilated. The ventilation system is to be independent of the
protected space. Any entrance to the storage room is to be independent of the protected space, except that
where this is impracticable due to space limitations, the following requirements may be considered:
i) The door between the storage location and the protected space is to be self-closing with no hold-
back arrangements.
ii) The space where cylinders are stored is to be adequately ventilated by a system which is independent
of the protected space.

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Part 4 Vessel Systems and Machinery
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Section 3 Requirements for Vessels Under 500 Gross Tons 4-5-3

iii) Means are to be provided to prevent unauthorized release of gas, such as containment behind a
break glass.
iv) There is to be provision to vent the bottles to the atmosphere in order to prevent a hazard to
personnel occupying the storage area.
v) An additional entrance to the storage location, independent of the protected space, is provided.

7 Axe
One fire axe is to be provided on each vessel 20 m (65 ft) in length and over.

9 Vessels Intended to Carry Oil in Bulk

9.1 Cargo Pump Rooms

Cargo pump rooms are to be provided with an approved fixed fire extinguishing system controlled from
the deck.

9.3 Cargo Tank Protection

For tankers of 30.5 m (100 ft) in length and above, a deck foam system is to be installed for the protection
of all cargo tanks. For tankers less than 30.5 m (100 ft) in length, two B-V extinguishers (see 4-5-1/Table 1)
are to be provided for the protection of the cargo tanks.

TABLE 1
Fire Pump Minimum Capacity for Vessels Less Than 500 Gross Tons
Vessel Length Minimum Capacity
Less than 20 m (65 ft) 5.50 m3/hr (25 gpm)
20 m (65 ft) or greater but less than 30.5 m (100 ft) 11.0 m3/hr (50 gpm)
30.5 m (100 ft) or greater but less than 61 m (200 ft) 14.3 m3/hr (66.6 gpm)
61 m (200 ft) or greater Capacity to be in accordance with 4-5-2/5.1

168 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Chapter 6: Electrical Installations

4
CHAPTER 6 Electrical Installations

CONTENTS
SECTION 1 General................................................................................................ 177
1 Applications.....................................................................................177
3 Definitions .......................................................................................177
3.1 Earthed Distribution System ........................................................ 177
3.3 Essential Services ....................................................................... 177
3.5 Explosion-proof (Flameproof) Equipment .................................... 177
3.7 Hazardous Area (Hazardous Location) ....................................... 178
3.9 Hull-return System....................................................................... 178
3.11 Intrinsically-safe........................................................................... 178
3.13 Increased Safety ......................................................................... 178
3.15 Non-periodic Duty Rating ............................................................ 178
3.17 Non-sparking Fan........................................................................ 178
3.19 Periodic Duty Rating.................................................................... 178
3.21 Portable Apparatus...................................................................... 178
3.23 Pressurized Equipment ............................................................... 179
3.25 Semi-enclosed Space ................................................................. 179
3.27 Separate Circuit........................................................................... 179
3.29 Short Circuit................................................................................. 179
3.31 Short-time Rating ........................................................................ 179
5 Plans and Data to Be Submitted.....................................................179
7 Standard Distribution System .........................................................179
9 Voltage and Frequency Variations..................................................179
11 Materials..........................................................................................179
13 Insulation Material...........................................................................180
13.1 Class A Insulation........................................................................ 180
13.3 Class B Insulation........................................................................ 180
13.5 Class E Insulation........................................................................ 180
13.7 Class F Insulation........................................................................ 180
13.9 Class H Insulation ....................................................................... 180
13.11 Insulation for Temperature Above 180°C (356°F) ....................... 180
15 Degree of Protection for Enclosure.................................................180
17 Temperature Ratings ......................................................................181
17.1 General........................................................................................ 181
17.3 Reduced Ambient Temperature .................................................. 181
19 Clearances and Creepage Distances .............................................181
21 Service Trial ....................................................................................182
21.1 Electrical Installation for Ship Services........................................ 182
21.3 Communication Facilities............................................................. 182

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 169
 TABLE 1 Voltage and Frequency Variations........................................182
TABLE 2 Degree of Protection of Electrical Equipment
(First IP Numeral)..................................................................183
TABLE 3 Degree of Protection of Electrical Equipment
(Second IP Numeral).............................................................184
TABLE 4 Primary Essential Services ...................................................184
TABLE 5 Secondary Essential Services ..............................................185

SECTION 2 Shipboard Systems ............................................................................ 186

1 Plans and Data to be Submitted .....................................................186
1.1 Wiring ..........................................................................................186
1.3 Short-circuit Data .........................................................................187
1.5 Protective Device Coordination ...................................................187
1.7 Load Analysis ..............................................................................187
3 Ship Service Main Source of Power ...............................................187
3.1 Power Supply by Generators .......................................................187
3.3 Generator Driven by Propulsion Unit ...........................................188
3.5 Sizing of AC Generator................................................................189
5 Emergency Source of Power ..........................................................189
5.1 General........................................................................................189
5.3 Emergency Services....................................................................191
5.5 Power Supply ..............................................................................192
5.7 Transitional Source of Power.......................................................193
5.9 Emergency Switchboard..............................................................193
5.11 Arrangements for Periodic Testing ..............................................194
5.13 Vessels Intended to Carry Passengers........................................194
5.15 Starting Arrangements for Emergency Generator Sets ...............194
5.16 Use of Emergency Generator in Port (for Vessel 500 GT
and Over).....................................................................................195
5.17 Alarms and Safeguards for Emergency Diesel Engines ..............195
5.19 Vessels Less than 500 GT Having Electrical Plants of 75 kW
and Above ...................................................................................196
5.21 Requirements by the Governmental Authority .............................197
7 Distribution System .........................................................................197
7.1 Ship Service Distribution System.................................................197
7.3 Hull Return System......................................................................199
7.5 Earthed Distribution Systems ......................................................199
7.7 External or Shore Power Supply Connection...............................199
7.9 Harmonics ...................................................................................200
9 Circuit Protection System................................................................200
9.1 System Design ............................................................................200
9.3 Protection for Generators ............................................................201
9.5 Protection for Alternating-current (AC) Generators......................202
9.7 Protection for Direct Current (DC) Generators.............................203
9.9 Protection for Accumulator Batteries ...........................................203
9.11 Protection for External or Shore Power Supply ...........................204
9.13 Protection for Motor Branch Circuits ............................................204
9.15 Protection for Transformer Circuits ..............................................205
9.17 Protection for Meters, Pilot Lamps and Control Circuits ..............205

170 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 11 System for Steering Gear ...............................................................205
11.1 Power Supply Feeder .................................................................. 205
11.3 Protection for Steering Gear Circuit............................................. 206
11.5 Emergency Power Supply ........................................................... 206
11.7 Controls, Instrumentation, and Alarms ........................................ 206
13 Lighting and Navigation Light Systems...........................................206
13.1 Lighting System........................................................................... 206
13.3 Navigation Light System.............................................................. 207
15 Interior Communication Systems....................................................208
15.1 Navigation Bridge ........................................................................ 208
15.3 Main Propulsion Control Stations ................................................ 208
15.5 Voice Communications................................................................ 208
15.7 Emergency and Interior-communication Switchboard ................. 208
15.9 Public Address System................................................................ 209
17 Manually Operated Alarms .............................................................209
17.1 General Emergency Alarm System ............................................. 209
17.3 Engineers’ Alarm ......................................................................... 210
17.5 Refrigerated Space Alarm ........................................................... 210
17.7 Elevator ....................................................................................... 210
19 Fire Protection and Fire Detection Systems ...................................211
19.1 Emergency Stop.......................................................................... 211
19.3 Fire Detection and Alarm System................................................ 211

TABLE 1 Alarms and Safeguards for Emergency Diesel Engines.......196

FIGURE 1 Cofferdam with Extension Beyond the Boundaries of

the Space Containing the Emergency Source......................190
FIGURE 2 Cofferdam without Extension Beyond the Boundaries of
the Space Containing the Emergency Source......................190
FIGURE 3 Boundary Insulated to A-60 with the Insulation Extending
Beyond the Boundaries of the Space Containing the
Emergency Source ...............................................................191

SECTION 3 Shipboard Installation........................................................................ 212

1 Plans and Data to be Submitted .....................................................212
1.1 Booklet of Standard Details ......................................................... 212
1.3 Arrangement of Electrical Equipment .......................................... 212
1.5 Electrical Equipment in Hazardous Areas ................................... 212
1.7 Maintenance Schedule of Batteries............................................. 213
3 Equipment Installation and Arrangement........................................213
3.1 General Consideration ................................................................ 213
3.3 Generators .................................................................................. 214
3.5 Ship Service Motors .................................................................... 214
3.7 Accumulator Batteries ................................................................. 215
3.9 Switchboard................................................................................. 217
3.11 Distribution Boards ...................................................................... 217
3.13 Motor Controllers and Control Centers ........................................ 218

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 3.15 Resistors for Control Apparatus...................................................218
3.17 Lighting Fixtures ..........................................................................218
3.19 Heating Equipment ......................................................................219
3.21 Magnetic Compasses ..................................................................219
3.23 Portable Equipment and Outlets ..................................................219
3.25 Receptacles and Plugs of Different Ratings ................................219
3.27 Installation Requirements for Recovery from Dead Ship
Condition .....................................................................................219
3.29 Services Required to be Operable Under a Fire Condition..........219
3.31 High Fire Risk Areas....................................................................220
5 Cable Installation ............................................................................220
5.1 General Considerations ...............................................................220
5.3 Insulation Resistance for New Installation ...................................221
5.5 Protection for Electric-magnetic Induction ...................................221
5.7 Joints and Sealing .......................................................................222
5.9 Support, Fixing and Bending .......................................................222
5.11 Cable Run in Bunches .................................................................223
5.13 Deck and Bulkhead Penetrations ................................................224
5.15 Mechanical Protection .................................................................224
5.17 Emergency and Essential Feeders ..............................................224
5.19 Mineral Insulated Cables .............................................................225
5.21 Fiber Optic Cables .......................................................................225
5.23 Battery Room...............................................................................225
5.25 Paneling and Dome Fixtures .......................................................226
5.27 Sheathing and Structural Insulation .............................................226
5.29 Splicing of Electrical Cables ........................................................226
5.31 Splicing of Fiber Optic Cables .....................................................226
5.33 Cable Junction Box......................................................................226
7 Earthing...........................................................................................227
7.1 General........................................................................................227
7.3 Permanent Equipment .................................................................227
7.5 Connections.................................................................................228
7.7 Portable Cords.............................................................................228
7.9 Cable Metallic Covering...............................................................228
7.11 Lightning Earth Conductors .........................................................228
9 Installation in Cargo Hold for Dry Bulk Cargoes .............................228
9.1 Equipment ...................................................................................228
9.3 Self-Unloading Controls and Alarms............................................228
11 Equipment and Installation in Hazardous Areas.............................229
11.1 General Considerations ...............................................................229
11.3 Certified-safe Type and Pressurized Equipment and
Systems.......................................................................................229
11.5 Paint Stores .................................................................................231
11.7 Non-sparking Fans ......................................................................231

TABLE 1 Minimum Degree of Protection .............................................233

TABLE 2 Minimum Bending Radii of Cables........................................234
TABLE 3 Size of Earth-continuity Conductors and Earthing
Connections ..........................................................................234

172 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 FIGURE 1 Example of Protected Area, Adjacent Area of Direct
Spray and Adjacent Area where Water May Extend ............214
FIGURE 2 Cables within High Fire Risk Areas.......................................225

SECTION 4 Machinery and Equipment................................................................. 235

1 Plans and Data to Be Submitted.....................................................235
1.1 Rotating Machines of 100 kW and Over ...................................... 235
1.3 Switchboards, Distribution Boards, Controllers, etc..................... 235
3 Rotating Machines ..........................................................................235
3.1 General........................................................................................ 235
3.3 Testing and Inspection ................................................................ 236
3.5 Insulation Resistance Measurement ........................................... 236
3.7 Overload and Overcurrent Capability .......................................... 237
3.9 Dielectric Strength of Insulation................................................... 237
3.11 Temperature Ratings................................................................... 237
3.13 Construction and Assemblies ...................................................... 238
3.15 Lubrication................................................................................... 239
3.17 Turbines for Generators .............................................................. 239
3.19 Diesel Engines for Generators .................................................... 240
3.21 Alternating-current (AC) Generators............................................ 241
3.23 Direct-current (DC) Generators ................................................... 242
5 Accumulator Batteries.....................................................................243
5.1 General........................................................................................ 243
5.3 Construction and Assembly......................................................... 244
5.5 Engine-starting Battery ................................................................ 244
7 Switchboards, Distribution Boards, Controllers, etc. ......................244
7.1 General........................................................................................ 244
7.3 Testing and Inspection ................................................................ 245
7.5 Insulation Resistance Measurement ........................................... 246
7.7 Dielectric Strength of Insulation................................................... 246
7.9 Construction and Assembly......................................................... 246
7.11 Bus Bars, Wiring and Contacts.................................................... 247
7.13 Control and Protective Devices ................................................... 247
7.15 Switchboards............................................................................... 248
7.17 Motor Controllers and Control Centers ........................................ 249
7.19 Battery Systems and Uninterruptible Power Systems (UPS)....... 249
9 Transformers...................................................................................251
9.1 General........................................................................................ 251
9.3 Temperature Rise........................................................................ 251
9.5 Construction and Assembly......................................................... 252
9.7 Testing......................................................................................... 252
11 Other Electric and Electronics Devices...........................................252
11.1 Circuit Breakers........................................................................... 252
11.3 Fuses........................................................................................... 253
11.5 Semiconductor Converters .......................................................... 253
11.7 Cable Junction Boxes.................................................................. 253

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 173
 13 Cables and Wires............................................................................253
13.1 Cable Construction ......................................................................253
13.3 Portable and Flexing Electric Cables ...........................................255
13.5 Mineral-insulated Metal-sheathed Cable .....................................255

TABLE 1 Factory Test Schedule for Generators and Motors

≥ 100 kW (135 hp).................................................................256
TABLE 2 Dielectric Strength Test for Rotating Machines ....................257
TABLE 3 Limits of Temperature Rise for Air-Cooled Rotating
Machines...............................................................................258
TABLE 4 Nameplates ...........................................................................259
TABLE 5 Factory Testing Schedule for Switchboards, Chargers,
Motor Control Centers and Controllers .................................260
TABLE 6 Clearance and Creepage Distance for Switchboards,
Distribution Boards, Chargers, Motor Control Centers
and Controllers......................................................................260
TABLE 7 Equipment and Instrumentation for Switchboard..................261
TABLE 8 Temperature Rise for Transformers......................................262
TABLE 9 Types of Cable Insulation .....................................................262
TABLE 10 Maximum Current Carrying Capacity for Insulated Copper
Wires and Cables..................................................................263
TABLE 11 Additional Services Requiring Electrical Equipment to be
Designed, Constructed and Tested to the Requirements
in Section 4-6-4 .....................................................................265

FIGURE 1 Limiting Curves for Loading 4-stroke Diesel Engines Step

by Step from No-load to Rated Power as Function of the
Brake Mean Effective Pressure ............................................241

SECTION 5 Specialized Installations .................................................................... 266

1 High Voltage Systems.....................................................................266
1.1 General........................................................................................266
1.3 System Design ............................................................................266
1.5 Circuit Breakers and Switches – Auxiliary Circuit Power
Supply Systems ...........................................................................267
1.7 Circuit Protection .........................................................................267
1.9 Equipment Installation and Arrangement.....................................268
1.11 Machinery and Equipment ...........................................................270
3 Electric Propulsion System .............................................................272
3.1 General........................................................................................272
3.3 System Design ............................................................................272
3.5 Propulsion Power Supply Systems ..............................................273
3.7 Circuit Protection .........................................................................274
3.9 Protection for Earth Leakage .......................................................275
3.11 Electric Propulsion Control ..........................................................275
3.13 Instrumentation at the Control Station .........................................276
3.15 Equipment Installation and Arrangement.....................................277
3.17 Machinery and Equipment ...........................................................277
3.19 Dock and Sea Trials ....................................................................281

174 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 5 Three-wire Dual-voltage DC System ..............................................281
5.1 Three-wire DC Ship’s Generators ............................................... 281
5.3 Neutral Earthing .......................................................................... 281
5.5 Size of Neutral Conductor ........................................................... 281
7 Electrical Plants of Less Than 75 kW .............................................281
7.1 General........................................................................................ 281
7.3 Standard Details.......................................................................... 281
7.5 Calculations of Short-circuit Currents .......................................... 282
7.7 Lightning Protection..................................................................... 282
7.9 Temperature Ratings................................................................... 282
7.11 Generators .................................................................................. 282
7.13 Emergency Source of Power....................................................... 282
7.15 Cable Construction...................................................................... 282
7.17 Switchboards, Distribution Boards and Panels............................ 283
7.19 Navigation Running Lights........................................................... 283

SECTION 6 Specialized Vessels and Services .................................................... 284

1 Oil Carriers......................................................................................284
1.1 Application................................................................................... 284
1.3 Earthed Distribution Systems ...................................................... 284
1.5 Hazardous Areas......................................................................... 284
1.7 Enclosed Spaces Separated from Hazardous Areas by Air
Locks ........................................................................................... 286
1.9 Installation of Equipment and Cables .......................................... 286
1.11 Spaces Above Forepeak Tank .................................................... 287
1.13 Cargo Oil Pump Room ................................................................ 287
1.15 Gas Monitoring System Installation ............................................. 288
1.17 Pipe Tunnel or Duct Keel............................................................. 289
1.19 Gas Detection for Double Hull and Double Bottom Spaces
in the Cargo Area ........................................................................ 289
1.21 Integrated Cargo and Ballast Systems – All Cargo Flash
Points .......................................................................................... 289
3 Vessels Carrying Coal in Bulk ........................................................290
3.1 Application................................................................................... 290
3.3 Hazardous Areas......................................................................... 290
3.5 Installation of Equipment ............................................................. 290
5 Cargo Vessels Carrying Motor Vehicles with Fuel in Their
Tank ................................................................................................291
5.1 Application................................................................................... 291
5.3 Ventilation System....................................................................... 291
5.5 Location and Type of Equipment................................................. 292
7 Ro-Ro Vessels ................................................................................292
7.1 Application................................................................................... 292
7.3 Ro-Ro Cargo Spaces .................................................................. 293
9 Gas Carriers or Chemical Carriers .................................................293
9.1 Gas Carriers ................................................................................ 293
9.3 Chemical Carriers........................................................................ 293

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 175
 TABLE 1 Electrical Equipment in Hazardous Areas for Oil
Carriers .................................................................................294

FIGURE 1 Typical Hazardous Areas on Open Deck..............................285

176 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 1: General

4
CHAPTER 6 Electrical Installations

SECTION 1 General

1 Applications
Electrical apparatus and wiring systems are to be constructed and installed to the satisfaction of the Surveyor,
in accordance with the following requirements which are applicable to all ocean-going vessels, but which
may be modified for vessels classed for limited service. The following detailed rules are minimum requirements
for classification purposes. Consideration will be given, however, to arrangements or details which can be
shown to comply with other recognized standards, provided they are not less effective.
For vessels having an aggregate generator capacity not exceeding 75 kW, the requirements contained in 4-6-5/7
are to be complied with. Electrical installations in machinery spaces with gasoline engines will be specially
considered.

3 Definitions
The following definitions apply for the purpose of this Section.

3.1 Earthed Distribution System

A system in which one pole of a single phase system or the neutral point of a three phase system is earthed,
but the earthing connection does not normally carry current.

3.3 Essential Services (2004)

Essential services are those considered necessary for:
• Continuous operation to maintain propulsion and steering (primary essential services);
• Non-continuous operation to maintain propulsion and steering and a minimum level of safety for the
vessel’s navigation and systems, including safety for dangerous cargoes to be carried (secondary essential
services); and
• Emergency services as described in 4-6-2/5.3 (each service is either primary essential or secondary essential
depending upon its nature).
Examples of primary essential services and secondary essential services are as listed in 4-6-1/Table 4 and
4-6-1/Table 5, respectively.

3.5 Explosion-proof (Flameproof) Equipment

Explosion-proof equipment is equipment:
3.5.1
Having an enclosure capable of:
i) Withstanding an explosion within it of a specified flammable gas or vapor, and
ii) Preventing the ignition of the specified flammable gas or vapor in the atmosphere surrounding
the enclosure by sparks, flashes or explosions of the gas or vapor within, and

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

3.5.2
Operates at such an external temperature that a surrounding flammable atmosphere will not be
ignited. Where explosion-proof equipment is required by these Rules, equipment certified as being
flameproof, as defined in IEC Publication 60079 or other recognized standard may be accepted.

3.7 Hazardous Area (Hazardous Location)

An area where flammable or explosive vapor, gas, or dust may normally be expected to accumulate.

3.9 Hull-return System

A system in which insulated conductors are provided for connection to one pole or phase of the supply, the
hull of the vessel or other permanently earthed structure being used for effecting connections to the other
pole or phase.

3.11 Intrinsically-safe
A circuit or part of a circuit is intrinsically safe when any spark or any thermal effect produced in the test
conditions prescribed in a recognized standard (such as IEC Publication 60079-11) is incapable of causing
ignition of the prescribed explosive gas atmosphere.
3.11.1 Category “ia”
Apparatus which is incapable of causing ignition in normal operation, or with a single fault, or
with any combination of two faults applied, with the following safety factors:
In normal operation: 1.5
With one fault: 1.5
With two faults: 1.0
Above safety factors are applied to the current, voltage, or their combination, as specified in 10.4.1
of IEC Publication 60079-11.

3.13 Increased Safety

Type of protection applied to electrical apparatus that does not produce arcs or sparks in normal service, in
which additional measures are applied so as to give increased security against the possibility of excessive
temperatures and of the occurrence of arc and sparks. See IEC Publication 60079-7.

3.15 Non-periodic Duty Rating

A rating at which the machine is operated continuously or intermittently with varying load and speed within
the permissible operating range. The load and speed variations include the overloads applied frequently,
which may greatly exceed the full load rating of the machine.

3.17 Non-sparking Fan

A fan consisting of a combination of impeller and housing which are unlikely to produce sparks by static
electricity or by entry of foreign objects in both normal and abnormal conditions.

3.19 Periodic Duty Rating

A rating at which the machine is operated repeatedly on a cycle of sequential loading with starting, electric
braking, no-load running, rest and de-energized periods, where applicable. The time for the duration of
operating cycle (duty cycle) is to be 10 minutes and the ratio (i.e., cyclic duration factor) between the
period of loading (including starting and electric braking) and the duty cycle is to be one of the values of
15%, 25%, 40% or 60%.

3.21 Portable Apparatus

Portable apparatus is any apparatus served by a flexible cord.

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Part 4 Vessel Systems and Machinery
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Section 1 General 4-6-1

3.23 Pressurized Equipment

Equipment having an enclosure in which positive pressure is maintained to prevent against the ingress of
external atmosphere and complying with the requirements in 4-6-3/11.3.3.

3.25 Semi-enclosed Space

A space limited by decks and/or bulkheads in such a manner that the natural conditions of ventilation in the
space are notably different from those obtained on open deck.

3.27 Separate Circuit

A circuit which is independently protected by a circuit protection device at the final sub-circuit and is
dedicated to a single load.

3.29 Short Circuit

A short circuit is an abnormal connection through a negligible impedance, whether made accidentally or
intentionally, between two points of different potential in a circuit.

3.31 Short-time Rating

A rating at which the machine is operated for a limited period, which is less than that required to reach the
steady temperature condition, followed by a rest and de-energized period of sufficient duration to re-establish
the machine temperature within 2°C (3.6°F) of the coolant.

5 Plans and Data to Be Submitted

See 4-6-2/1, 4-6-3/1, 4-6-4/1 and 4-6-5/3.3.

7 Standard Distribution System

The following are recognized as standard systems of distribution. Distribution systems differing from these
will be specially considered.
• Two-wire direct current
• Three-wire direct current
• Two-wire single-phase alternating
• Three-wire three-phase alternating current*
• Four-wire three-phase alternating current
* Note: Three-wire single-phase AC may be used in conjunction with this system for lighting.

9 Voltage and Frequency Variations (2008)

Electrical appliances supplied from the main or emergency systems, are to be so designed and manufactured
that they are capable of being operated satisfactorily under the normally occurring variations in voltage and
frequency. Unless otherwise stated in national or international standards, the variations from the rated value
may be taken from the 4-6-1/Table 1. Any special system, such as electronic circuits, which cannot operate
satisfactorily within the limit shown in 4-6-1/Table 1, is not to be supplied directly from the system but by
alternative means, such as through a stabilized supply.
For generators, see 4-6-4/3.17.1, 4-6-4/3.19.1, and 4-6-4/3.21.2.

11 Materials
All electrical equipment is to be constructed of durable and flame-retardant materials. Materials are to be
resistant to corrosion, moisture, high and low temperatures, and are to have other qualities necessary to prevent
deterioration in the ambient conditions that the equipment may be expected to encounter.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

13 Insulation Material
For the purposes of these requirements, insulating material is designated as follows.

13.1 Class A Insulation

Materials or combinations of materials such as cotton, silk and paper when suitably impregnated or coated
or when immersed in a dielectric liquid such as oil. Other materials or combinations of materials may be
included in this class if by experience or accepted tests they can be shown to be capable of operation at
105°C (221°F).

13.3 Class B Insulation

Materials or combinations of materials such as mica, glass fiber, etc., with suitable bonding substances.
Other materials or combinations of materials, not necessarily inorganic, may be included in this class if by
experience or accepted tests they can be shown to be capable of operation at 130°C (266°F).

13.5 Class E Insulation

Materials or combinations of materials which by experience or accepted tests can be shown to be capable
of operation at 120°C (248°F) (materials possessing a degree of thermal stability allowing them to be operated
at a temperature 15°C (27°F) higher than Class A materials).

13.7 Class F Insulation

Materials or combinations of materials such as mica, glass fiber, etc., with suitable bonding substances.
Other materials or combinations of materials, not necessarily inorganic, may be included in this class if by
experience or accepted tests they can be shown to be capable of operation at 155°C (311°F).

13.9 Class H Insulation

Materials or combinations of materials such as silicone elastomer, mica, glass fiber, etc., with suitable bonding
substances such as appropriate silicone resins. Other materials or combinations of materials may be included
in this class if by experience or accepted tests they can be shown to be capable of operation at 180°C (356°F).

13.11 Insulation for Temperature Above 180°C (356°F)

Materials or combination of materials which by experience or accepted tests can be shown to be capable of
satisfactory operation at temperature over 180°C (356°F) will also be considered. Supporting background
experience or report of tests conducted in accordance with a recognized standard ascertaining their suitability
for the intended application and temperature operation are to be submitted for review.

15 Degree of Protection for Enclosure

The designation to indicate the degree of protection consists of the characteristic letters IP followed by two
numerals (the “characteristic numerals”) indicating conformity with conditions stated in 4-6-1/Table 2 and
4-6-1/Table 3. The test and inspection for determining the degree of protection may be carried out in
accordance with IEC Publication 60529 by the manufacturer whose certificate of tests will be acceptable
and is to be submitted upon request from ABS. The type of enclosure required for protection of equipment
is to be suitable for the intended location. See 4-6-3/3.1.1 for selection of a protective enclosure for electrical
equipment based on location condition. Equipment in compliance with recognized national standards will
also be considered.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

17 Temperature Ratings

17.1 General
With the exception of equipment associated with control and monitoring systems described in Part 4,
Chapter 7, in the following requirements, an ambient temperature of 40°C (104°F) has been assumed for
locations outside of boiler and engine rooms while 45°C (113°F) has been assumed as the ambient temperature
for the latter spaces. However, electric rotating machines in boiler and engine rooms are to be rated for an
ambient temperature of 50°C (122°F). Where the ambient temperature is in excess of these values, the
equipment’s total rated temperature is not to be exceeded. Where equipment has been rated on ambient
temperatures less than those contemplated, consideration will be given to the use of such equipment,
provided the total temperature for which the equipment is rated will not be exceeded. For equipment
associated with control and monitoring systems described in Part 4, Chapter 7, refer to 4-7-2/15.9.2.

17.3 Reduced Ambient Temperature (2005)

17.3.1 Environmentally Controlled Spaces
Where electrical equipment is installed within environmentally-controlled spaces, the ambient
temperature for which the equipment is to be rated may be reduced from 45°C and maintained at a
value not less than 35°C, provided:
i) The equipment is not to be used for emergency services.
ii) Temperature control is achieved by at least two independent cooling systems so arranged
that in the event of loss of one cooling system for any reason, the remaining system(s) is
capable of satisfactorily maintaining the design temperature. The cooling equipment is to
be rated for a 45°C ambient temperature.
iii) The equipment is to be able to initially start to work safely at a 45°C ambient temperature
until such a time that the lesser ambient temperature may be achieved.
iv) Audible and visual alarms are provided, at a continually-manned control station, to indicate
any malfunction of the cooling systems.
17.3.2 Rating of Cables
In accepting a lesser ambient temperature than 45°C, it is to be ensured that electrical cables for
their entire length are adequately rated for the maximum ambient temperature to which they are
exposed along their length.
17.3.3 Ambient Temperature Control Equipment
The equipment used for cooling and maintaining the lesser ambient temperature is to be classified
as a secondary essential service, in accordance with 4-6-1/3.3, and the capability of cooling is to
be witnessed by the Surveyor at sea trial.

19 Clearances and Creepage Distances

The distances between live parts of different potential and between live parts and the case or other earthed
metal, whether across surfaces or in air, are to be adequate for working voltage having regard to the nature
of the insulating material and the conditions of service. See 4-6-4/7.11.6 and 4-6-5/1.1.4 for additional
requirements for switchboard and high voltage systems.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

21 Service Trial

21.1 Electrical Installation for Ship Services

All auxiliary apparatus is to be tried under working conditions. Each generator is to be run for a time sufficient
to show satisfactory operation, and parallel operation with all possible combinations is to be demonstrated.
Each auxiliary motor necessary to the operation of the vessel is to be run for a time sufficient to show
satisfactory performance at such load as can readily be obtained. All main switches and circuit breakers are
to be operated, but not necessarily at full load. The operation of the lighting system, heaters, etc., is to be
satisfactorily demonstrated. The entire installation is to operate to the satisfaction of the Surveyor, and the
drop in voltage on any part of the installation is not to exceed 6%. See 4-6-3/5.1.3.

21.3 Communication Facilities

Satisfactory operation of the interior communications system required by 4-6-2/15 is to be demonstrated to
the Surveyor during sea trials. Particular attention is to be given to demonstrating that the voice communication
systems required by 4-6-2/15 provide the capability of carrying on a conversation while the vessel is being
navigated.

TABLE 1
Voltage and Frequency Variations [See 4-6-1/9] (2008)
Voltage and Frequency Variations
for AC Distribution Systems
Quantity in Operation Permanent Variation Transient Variation
(Recovery Time)
Frequency ±5% ±10% (5 s)
Voltage +6%, −10% ±20% (1.5 s)

Voltage Variations for DC Distribution Systems

(such as systems supplied by DC generators or rectifiers)
Parameters Variations
Voltage tolerance (continuous) ±10%
Voltage cyclic variation deviation 5%
Voltage ripple (AC r.m.s over steady DC voltage) 10%

Voltage Variations for Battery Systems

Type of System Variations
Components connected to the battery during charging +30%, –25%
(see Note)
Components not connected to the battery during +20%, –25%
charging
Note: Different voltage variations as determined by the charging/discharging
characteristics, including the ripple voltage from the charging device,
may be considered.

182 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

TABLE 2
Degree of Protection of Electrical Equipment (First IP Numeral)
First IP Short Description Definition
Numeral
0 Non-protected No special protection

1 Protected against solid objects A large surface of the body, such as a hand (but no protection against deliberate
greater than 50 mm (2 in.) access). Solid object exceeding 50 mm (2 in.) in diameter.

2 Protected against solid objects Fingers or similar objects not exceeding 80 mm (3.15 in.) in length. Solid objects
greater than 50 mm (2 in.) exceeding 12 mm (0.5 in.) in diameter.

3 Protected against solid objects Tools, wires, etc. of diameter or thickness greater than 2.5 mm (0.1 in.). Solid
greater than 2.5 mm (0.1 in.) objects exceeding 2.5 mm (0.1 in.) in diameter

4 Protected against solid objects Wires or strips of thickness greater than 1 mm (0.04 in.). Solid objects exceeding
greater than 1 mm (0.04 in.) 1 mm (0.04 in.) in diameter.

5 Dust protected Ingress of dust is not totally prevented, but dust does not enter in sufficient quantity
to interfere with satisfactory operation of the equipment

6 Dust-tight No ingress of dust

[Designation]
The degree of protection is designated as shown in the following examples:
When it is required to indicate the degree of protection by only one characteristic numeral which shows either degree of
protection against foreign bodies and electrical shock or against liquid, the omitted numeral is to be replaced by the letter X.
Examples:
1 IP56 The first characteristic numeral of “5”
The second characteristic numeral of “6”.
2 IPX5 Degree of protection against only liquid.
3 IP2X Degree of protection against only foreign bodies and electrical shock.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

TABLE 3
Degree of Protection of Electrical Equipment (Second IP Numeral)
Second IP Short Description Definition
Numeral
0 Non-protected No special protection.

1 Protected against dripping Dripping water (vertically falling drops) is to have no harmful effect.
water

2 Protected against dripping Vertically dripping water is to have no harmful effect when the enclosure is tilted at
water when tilted up to 15°. any angle up to 15° from its normal position.

3 Protected against spraying Water falling as spray at an angle up to 60° from the vertical is to have no harmful
water effect.

4 Protected against splashing Water splashed against the enclosure from any direction is to have no harmful
water effect.

5 Protected against water jets Water projected by a nozzle against the enclosure from any direction is to have no
harmful effect.

6 Protected against heavy seas Water from heavy seas or water projected in powerful jets is not to enter the
enclosure in harmful quantities.

7 Protected against the effects Ingress of water in a harmful quantity is not to be possible when the enclosure is immersed
of immersion in water under defined conditions of pressure and time.

8 Protected against submersion The equipment is suitable for continuous submersion in water under conditions which are
to be specified by the manufacturer.
Note: Normally, this will mean that the equipment is hermetically sealed. However,
with certain types of equipment, it can mean that water can enter, but only in such a
manner that it produces no harmful effects.

See Designation and examples in 4-6-1/Table 2.

TABLE 4
Primary Essential Services (2010)
(a) Steering gears
(b) Pumps for controllable pitch propellers
(c) (2010) Scavenging air blower, fuel oil supply pumps, fuel valve cooling pumps, lubricating oil pumps and cooling water
pumps for main and auxiliary engines, turbines and shafting necessary for propulsion.
(d) Ventilation necessary to maintain propulsion
(e) Forced draft fans, feed water pumps, water circulating pumps, vacuum pumps and condensate pumps for steam plants on
steam turbine ships, and also for auxiliary boilers on vessels where steam is used for equipment supplying primary
essential services
(f) Oil burning installations for steam plants on steam turbine vessels and for auxiliary boilers where steam is used for
equipment supplying primary essential services
(g) (2010) Low duty gas compressor and other boil-off gas treatment facilities supporting boil-off gas usage as fuel to main
propulsion or electric power generation machinery.
(h) Azimuth thrusters which are the sole means for propulsion/steering with lubricating oil pumps, cooling water pumps, etc.
(i) Electrical equipment for electric propulsion plant with lubricating oil pumps and cooling water pumps
(j) Electric generators and associated power sources supplying primary essential equipment
(k) Hydraulic pumps supplying primary essential equipment
(l) Viscosity control equipment for heavy fuel oil
(m) Control, monitoring and safety devices/systems of equipment for primary essential services.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 1 General 4-6-1

TABLE 5
Secondary Essential Services (2010)
(a) Windlass
(b) Fuel oil transfer pumps and fuel oil treatment equipment
(c) Lubrication oil transfer pumps and lubrication oil treatment equipment
(d) Pre-heaters for heavy fuel oil
(e) Starting air and control air compressors
(f) Bilge, ballast and heeling pumps
(g) Fire pumps and other fire extinguishing medium pumps
(h) Ventilating fans for engine and boiler rooms
(i) Services considered necessary to maintain dangerous spaces in a safe condition (inert gas system of an oil carrier,
ventilation for Ro-Ro cargo spaces, etc.)
(j) (2010) Re-liquefaction plant on liquefied gas carriers
(k) Navigation lights, aids and signals
(l) Internal communication equipment required by 4-6-2/15
(m) Fire detection and alarm system
(n) Lighting system
(o) Electrical equipment for watertight and fire-tight closing appliances
(p) Electric generators and associated power sources supplying secondary essential equipment
(q) Hydraulic pumps supplying secondary essential equipment
(r) Control, monitoring and safety systems for cargo containment systems
(s) Control, monitoring and safety devices/systems of equipment for secondary essential services.
(t) (2005) Ambient temperature control equipment required by 4-6-1/17.3
(u) (2010) Watertight Doors (see Sections 3-2-7, 3-2-12 and 3-2-13)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 185
PART Section 2: Shipboard Systems

4
CHAPTER 6 Electrical Installations

SECTION 2 Shipboard Systems

1 Plans and Data to be Submitted

1.1 Wiring
1.1.1 Systems
One line diagrams for the following electrical systems are to be submitted for review.
• Power Supply and Distribution
• Lighting including Navigation Light
• Internal Communication
• General Emergency Alarm
• Fire Detection and Alarm
• Steering Gear Control
• Intrinsically-safe Equipment
• Emergency Generator Starting
• Inert Gas Control, Monitoring, and Alarm
1.1.2 Data for Wiring Systems
The one line diagrams are to show the circuit designation, type and size of cables, cable grouping
and banking, trip setting and rating of the circuit protection devices, the location of electrical
equipment accompanied by list of components, complete feeder list, rated load current for each
branch circuit. The one line diagram for power supply and distribution systems is to indicate the
following component details.
Note: For vessels having a length of 61 m (200 ft) and over, a voltage drop calculation for the longest run of
each cable size is to be included.

• Generator: kW rating, voltage, rated current, frequency, number of phases, power factor
• Batteries: type, voltage, capacity, conductor protection (when required)
• Motors: kW rating, remote stops (when required)
• Transformers: kVA rating, rated voltage and current on primary and secondary side,
connection method
The one line diagram for power supply and distribution systems is also to include a list of sequential
start of motors and equipment having emergency tripping or preferential tripping features.

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1.3 Short-circuit Data

In order to establish that the protective devices on the main and emergency switchboards have sufficient
short-circuit breaking and making capacities, data are to be submitted giving the maximum calculated
short-circuit current in symmetrical r.m.s. and asymmetrical peak values available at the main bus bars
together with the maximum allowable breaking and making capacities of the protective device. Similar
calculations are to be made at other points in the distribution system, where necessary, to determine the
adequacy of the interrupting capacities of the protective devices.

1.5 Protective Device Coordination

A protective device coordination study is to be submitted for review. This protective device coordination
study is to consist of an organized time-current study of all of the protective devices in series from the
utilization equipment to the source for all circuit protection devices having different setting or time-current
characteristics for long-time delay tripping, short-time delay tripping and instantaneous tripping, where
applicable. Where an over-current relay is provided in series and adjacent to the circuit protection device,
the operating and time-current characteristics of the relay are to be considered for coordination. See 4-6-2/9.1.5.

1.7 Load Analysis (2002)

An electric-plant load analysis is to be submitted for review. The electric-plant (including high voltage ship
service transformers or converters, where applicable per 4-6-2/7.1.6) load analysis is to cover all operating
conditions of the vessel, such as normal sea going, cargo handling (loading/unloading), harbor in/out and
emergency operations.

3 Ship Service Main Source of Power

3.1 Power Supply by Generators

3.1.1 Number of Generators
All oceangoing and Great Lakes vessels using electricity for ship’s service power or light are to be
provided with at least two electric generators for the ship service electrical demand.
3.1.2 Capacity of Generators (2009)
The capacity of the generating sets is to be such that in the event of any one generating set being
stopped, it will still be possible without recourse to the emergency source of power to supply those
services necessary to provide normal operational conditions of propulsion and safety, preservation
of the cargo and minimum comfortable conditions of habitability, which are to include at least
adequate services for cooking, heating, domestic refrigeration, mechanical ventilation, sanitary and
fresh water. See also 4-6-2/3.1.6. In addition, the generating sets are to be such that with any one
generator or its primary source of power out of operation, the remaining generating sets are capable
of providing the electrical services necessary to start the main propulsion plant in conjunction with
other machinery, as appropriate, from a dead ship condition, as defined in 4-1-1/13.21, within thirty
minutes of the blackout. See also 4-6-2/3.1.3.
3.1.3 Starting from Dead Ship Condition (2009)
In restoring the propulsion from a dead ship condition (see 4-1-1/13.21), no stored energy is to be
assumed available for starting the propulsion plant, the main source of electrical power and other
essential auxiliaries. It is assumed that means are available to start the emergency generator at all times.
The emergency source of electrical power may be used to restore the propulsion, provided its
capacity either alone or combined with that of any other available source of electrical power is
sufficient to provide at the same time those services required to be supplied by 4-6-2/5.3.2 to
4-6-2/5.3.3.

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The emergency source of electrical power and other means needed to restore the propulsion are to
have a capacity such that the necessary propulsion starting energy is available within 30 minutes
of blackout, as defined in 4-1-1/13.23. Emergency generator-stored starting energy is not to be
directly used for starting the propulsion plant, the main source of electrical power and/or other
essential auxiliaries (emergency generator excluded).
See also 4-6-2/3.1.6 and 4-6-4/7.15.2, below.
3.1.4 Power Supplied by Propulsion Generator
For vessels propelled by electric power and having two or more constant voltage propulsion generators,
the ship’s service electric power may be derived from this source and additional ship’s service
generators need not be fitted, provided that with one propulsion generator out of service, a speed
of seven knots or one-half of the design speed, whichever is the lesser, can be maintained. See
4-6-5/3.17.4 to 4-6-5/3.17.6.
3.1.5 Fuel Capacity for Generator Prime Mover
Where the fuel for any ship’s service generator prime mover differs from the fuel for the main
propulsion plant, adequate fuel capacity for that ship’s service generator prime mover with adequate
margins is to be provided for the longest anticipated run of the vessel between fueling ports.
3.1.6 System Arrangement (2004)
3.1.6(a) General. For vessels of 500 GT and above where the main source of electrical power is
necessary for propulsion and steering and the safety of the vessel, the system is to be so arranged
that the electrical supply to equipment necessary for these services is maintained or is capable of
being restored in the case of loss of any one of the generators in service in accordance with the
provision in 4-6-2/3.1.6(b) or 4-6-2/3.1.6(c).
Load shedding of nonessential services and, where necessary, secondary essential services (see
4-6-1/3.3) or other arrangements as may be necessary are to be provided to protect the generators
against the sustained overload. For main bus bar subdivision, see 4-6-4/7.15.2.
3.1.6(b) Single Generator Operation. Where the electrical power is normally supplied by a single
generator, provision is to be made upon loss of power for automatic starting and connecting to the
main switchboard of a stand-by generator(s) of sufficient capacity with automatic restarting of the
essential auxiliaries in sequential operation, if necessary to permit propulsion and steering and to
ensure the safety of the vessel. Starting and connection to the main switchboard of the standby
generator is to be preferably within 30 seconds after loss of the electrical power supply, but in no
case in more than 45 seconds.
3.1.6(c) Multiple Generator Operation. Where the electrical power is normally supplied by more
than one generator set simultaneously in parallel operation, the system is to be so arranged that in
the event of the loss of any one of the generators in service, the electrical supply to equipment
necessary for propulsion and steering and to ensure the safety of the vessel will be maintained by
the remaining generator(s) in service.

3.3 Generator Driven by Propulsion Unit (2004)

3.3.1 Constant Speed Drive
A generator driven by a main propulsion unit (shaft generator) capable of operating continuously
at a constant speed (e.g., a system where the vessel speed and direction are controlled only by
propeller pitch) may be considered to be one of the generators required by 4-6-2/3.1.1, provided
that the arrangements stated in i) to iii) below are complied with:
i) The generator and the generating systems are capable of maintaining the voltage and
frequency variation within the limits specified in 4-6-4/3.21.2 and 4-6-1/Table 1 under all
weather conditions during sailing or maneuvering and also while the vessel is stopped.
ii) The rated capacity of the generator and the generating systems is safeguarded during all
operations given under i) and is such that the services required by 4-6-2/3.1.2 can be
maintained upon loss of any generator in service.
iii) An arrangement is made for starting a standby generator and connecting it to the switchboard,
in accordance with 4-6-2/3.1.6.

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3.3.2 Variable Speed Drive

Shaft generator installations not capable of operating continuously at a constant speed may be used
for normal operational and habitable conditions of the vessel, provided that the arrangements
stated in i) to v) below are complied with. This type of generator will not be counted as one of the
generators required by 4-6-2/3.1.2.
i) In addition to this type of generator, generators of sufficient and adequate rating are provided,
which constitute the main source of electrical power required by 4-6-2/3.1.2.
ii) When the frequency variations at the main bus bar exceed the following limits due to the
speed variation of the propulsion machinery which drives the generator, arrangements are
made to comply with 4-6-2/3.1.6.
Permanent frequency variation: ± 5.5%
Transient frequency variation: ± 11% (5 sec)
iii) The generators and the generating systems are capable of maintaining the voltage and
frequency variation within the limits specified in 4-6-4/3.21.2 and 4-6-1/Table 1.
iv) Where load-shedding arrangements are provided, they are fitted in accordance with
4-6-2/9.3.3.
v) Where the propulsion machinery is capable of being operated from the navigation bridge,
means are provided or procedures are in place to ensure that power supply to essential
services is maintained during maneuvering conditions in order to avoid a blackout situation.

3.5 Sizing of AC Generator

In selecting the capacity of an alternating-current generating plant, particular attention is to be given to the
starting current of motors forming part of the system. Under the normal seagoing condition of the vessel
with one generator held in reserve as a standby, the remaining generator sets, operating in parallel and
initially carrying the minimum load necessary for operating the vessel, are to have sufficient capacity with
respect to the largest idle motor on the vessel so that the motor can be started and the voltage drop
occasioned by its starting current will not cause any already running motor to stall or control equipment to
drop out.

5 Emergency Source of Power

5.1 General
A self-contained emergency source of electrical power is to be provided.
5.1.1 Location
The emergency source of electrical power, its associated transforming equipment, if any, transitional
source of emergency power, the emergency switchboard, the emergency lighting switchboard and
the fuel oil tank for the emergency generator prime mover are to be located above the uppermost
continuous deck outside of the machinery casing, and are to be readily accessible from the open
deck. They are not to be located forward of the collision bulkhead.
5.1.2 Separation
5.1.2(a) Machinery Space of Category A. The location of the emergency source of electrical power,
its associated transforming equipment, if any, and the emergency switchboard, and the transitional
source of emergency power (if required) is to be such that a fire or other casualty in the space
containing the main source of electrical power, its associated transforming equipment, if any, and
the main switchboard, or in any machinery space of category A will not interfere with the supply,
control and distribution of emergency electrical power. As far as practicable, the space containing
the emergency source of electrical power, associated transforming equipment, if any, the transitional
source of emergency electrical power and the emergency switchboard, including trunks to such
spaces, are not to be contiguous to the boundaries of machinery spaces of category A or those
spaces containing the main source of electrical power, associated transforming equipment, if any,
and the main switchboard.

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5.1.2(b) Machinery Space Other Than Category A. Spaces containing emergency sources of
power are to be separated from machinery spaces (as defined in 4-1-1/13.3), other than Category
A machinery spaces, by a boundary insulated to a level of not less than A-15 for bulkheads and
decks and A-0 for the overhead from any such space (including trunks to such spaces). Where the
emergency source of power is a generator, the above is not intended to preclude the location of the
emergency generator in the same space as its prime mover, regardless of size.
5.1.2(c) Alternative Arrangement (2008). The following alternative arrangements may be considered
in lieu of 4-6-2/5.1.2(a):
i) Separation by a cofferdam having dimensions as required for ready access and extending
at least 150 mm (6 in.) beyond the boundaries of the space containing the self-contained
emergency source of power and its associated equipment as stated in 4-6-2/5.1.2(a). See
4-6-2/Figure 1 below. Except for cables feeding services located in the machinery space,
emergency electric cables are not to be installed in such cofferdams unless the cofferdam
is insulated to A-60.

FIGURE 1
Cofferdam with Extension Beyond the Boundaries of
the Space Containing the Emergency Source (2008)

Space containing emergency 150 mm (6 in.)

source of power and its
associated equipment

Cofferdam

Category A Machinery Space

ii) Separation by a cofferdam having dimensions as required for ready access between
category A machinery space and the space containing the self-contained emergency
source of power and its associated equipment as stated in 4-6-2/5.1.2(a) without extension
beyond the boundaries. Any contiguous lines between these spaces at the corner of the
cofferdam are to be insulated to A-60 for a length of 450 mm (18 in.) at the category A
machinery space side. See 4-6-2/Figure 2 below.

FIGURE 2
Cofferdam without Extension Beyond the Boundaries of
the Space Containing the Emergency Source (2008)

A-60 insulation Space containing emergency 450 mm (18 in.)

source of power and its
associated equipment

Cofferdam

Category A Machinery Space

iii) The contiguous boundaries insulated to A-60 with the insulation extending at least 450 mm
(18 in.) beyond the boundary of the space containing the self-contained emergency source
of power and its associated equipment as stated in 4-6-2/5.1.2(a). See 4-6-2/Figure 3 below.

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The arrangements indicated in 4-6-2/Figure 3 below can be considered only when it can
be shown that the arrangements are in compliance with the requirements of the flag
administration.

FIGURE 3
Boundary Insulated to A-60 with the Insulation
Extending Beyond the Boundaries of the Space
Containing the Emergency Source (2008)

A-60 insulation Space containing emergency 450 mm (18 in.)

source of power and its
associated equipment

Category A Machinery Space

5.3 Emergency Services

5.3.1 General
The electrical power available is to be sufficient to supply all of those services that are essential
for safety in an emergency, due regard being paid to such services as may have to be operated
simultaneously and for equipment which can be shown as not being required in actual service to
draw their rated loads. In the latter case, supporting details are to be submitted. The emergency
source of electrical power is to be capable, having regard to starting currents and the transitory
nature of certain loads, of supplying simultaneously at least the following services for the period
specified in 4-6-2/5.3.1 to 4-6-2/5.3.7, if they depend upon an electrical source for their operation.
5.3.2 Lighting Systems and Navigation Light
5.3.2(a) Emergency Lighting for 3 hours:
i) At muster and embarkation stations for the survival craft
ii) At the survival craft, their launching appliances and the area of water into which they are
to be launched.
5.3.2(b) Emergency Lighting for 18 hours:
i) In all service and accommodation alleyways, stairways and exits, personnel elevators and
shafts;
ii) In the machinery spaces and main generating stations, including their control positions;
iii) In all control stations, machinery control rooms, and at each main and emergency
switchboard;
iv) At all stowage positions for firemen’s outfits;
v) At the steering gear; and
vi) At the fire pump referred to in 4-6-2/5.3.4, at the sprinkler pump, if any, at the emergency
bilge pump, if any, and at the starting positions of their motors.
vii) (1 July 2002) In all cargo pump-rooms of tankers 500 GT and over which have their keel
laid or are in a similar stage of construction on or after 1 July 2002.
5.3.2(c) For period of 18 hours:
i) Navigation lights and other lights required by the International Regulation for Preventing
Collisions at Sea in force.

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5.3.3 Communication System, Navigation Aid, and Alarm Systems

For a period of 18 hours:
5.3.3(a) VHF radio installation required by Regulation IV/7.1.1 and IV/7.1.2 of SOLAS 1974, as
amended; and if applicable:
i) The MF radio installation required by Regulation IV/9.1.1, IV/9.1.2, IV/10.1.2 and IV/10.1.3
of SOLAS 1974 as amended
ii) The ship earth station required by Regulation IV/10.1.1 of SOLAS 1974 as amended
iii) The MF/HF radio station required by Regulation IV/10.2.1, IV/10.2.2 and IV/11.1 of
SOLAS 1974 as amended.
5.3.3(b) All internal communication equipment as required in an emergency
5.3.3(c) Shipborne navigational equipment (i.e., radar, gyro compass, etc.), as required by Regulation
V/12 of SOLAS 1974 as amended except that where such provision is unreasonable or impracticable
for vessels less than 5,000 GT, this may be waived if evidence of approval by the Administration
is submitted.
5.3.3(d) Required fire detection and fire alarm systems
5.3.3(e) Intermittent operation of the daylight signaling lamp, the ship’s whistle, manually operated
call points and other internal signals that are required in an emergency, unless such services have
an independent supply for the period of 18 hours from an accumulator battery suitably located for
use in an emergency.
5.3.4 Emergency Fire Pump
For period of 18 hours, one of the fire pumps required by 4-5-2/5.3 if dependent upon the emergency
generator for its source of power.
5.3.5 Steering Gear
Steering gear to comply with 4-6-2/11.5 if powered from emergency source for a period of
10 minutes continuous operation on vessels of less than 10,000 GT.
5.3.6 Emergency Control and Monitoring Systems
Emergency control monitoring systems, as required by 4-7-4/11.
5.3.7 Vessels on Short Duration Voyages
In a vessel engaged regularly in voyages of short duration where an adequate standard of safety is
attained, a lesser period than the 18 hour period specified in 4-6-2/5.3.2(b), 4-6-2/5.3.2(c), 4-6-2/5.3.3,
and 4-6-2/5.3.4, but not less than 12 hours may be accepted.
5.3.8 Other Emergency Services (2005)
For a period of 30 minutes for the following:
i) Free-fall lifeboat secondary launching appliance, if the secondary launching appliance is
not dependent on gravity, stored mechanical power or other manual means, and
ii) Power-operated watertight door, as required by 3-2-7/7.1.1.

5.5 Power Supply

5.5.1 General
The emergency source of electrical power may be either a generator or an accumulator battery, in
accordance with 4-6-2/5.5.2 or 4-6-2/5.5.3, below:
5.5.2 Generator
Where the emergency source of electrical power is a generator, it is to be:
5.5.2(a) driven by a prime mover with an independent supply of fuel having a flashpoint (closed
cup test) of not less than 43°C (110°F), and

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5.5.2(b)
i) Started automatically upon failure of the main source of electrical power supply and
connected automatically to the emergency switchboard – then, those services referred to
in 4-6-2/5.7 are to be connected automatically to the emergency generator as quickly as is
safe and practicable, subject to a maximum of 45 seconds, or
ii) Provided with a transitional source of emergency electrical power, as specified in 4-6-2/5.7,
unless an emergency generator is provided capable both of supplying the services referred
to in 4-6-2/5.7 of being automatically started and supplying the required load as quickly
as is safe and practicable, subject to a maximum of 45 seconds, and
5.5.2(c) An adequate fuel capacity for the emergency generator prime mover is to be provided.
5.5.3 Accumulator Battery
Where the emergency source of electrical power is an accumulator battery, it is to be capable of:
5.5.3(a) carrying the emergency electrical load without recharging while maintaining the voltage
of the battery throughout the discharge period within 12% above or below its nominal voltage;
5.5.3(b) automatically connecting to the emergency switchboard in the event of failure of the
main source of electrical power; and
5.5.3(c) immediately supplying at least those services specified in 4-6-2/5.7.
5.5.4 Emergency Generator for Non-emergency Services (2004)
Provided that suitable measures are taken for safeguarding independent emergency operation under
all circumstances, the emergency generator may be used, exceptionally, and for short periods, to
supply non-emergency circuits during the blackout situation (see 4-1-1/13.23) dead ship condition
(see 4-1-1/13.21), and routine use for testing (see 4-6-2/5.11). The generator is to be safeguarded
against overload by automatically shedding such non-emergency services so that supply to the
required emergency loads is always available. See also 4-6-2/5.9.5.
For use of the emergency generator in port, see 4-6-2/5.16.

5.7 Transitional Source of Power

The transitional source of emergency electrical power, where required by 4-6-2/5.5.2(b)ii), is to consist of
an accumulator battery which is to operate without recharging while maintaining the voltage of the battery
throughout the discharge period within 12% above or below its nominal voltage and be of sufficient
capacity and be so arranged as to supply automatically in the event of failure of either the main or the
emergency source of electrical power for half an hour at least the following services if they depend upon
an electrical source for their operation:
i) The lighting required by 4-6-2/5.3.2. For this transitional phase, the required emergency electric
lighting, in respect of the machinery space and accommodation and service spaces, may be provided
by permanently fixed, individual, automatically charged, relay operated accumulator lamps; and
ii) All services required by 4-6-2/5.3.3(b), 4-6-2/5.3.3(d) and 4-6-2/5.3.3(e), unless such services have
an independent supply for the period specified from an accumulator battery suitably located for
use in an emergency.

5.9 Emergency Switchboard

5.9.1 General
The emergency switchboard is to be installed as near as is practicable to the emergency source of
electrical power.
5.9.2 Emergency Switchboard for Generator
Where the emergency source of electrical power is a generator, the emergency switchboard is to
be located in the same space unless the operation of the emergency switchboard would thereby be
impaired.

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5.9.3 Accumulator Battery

No accumulator battery fitted in accordance with 4-6-2/5.5.3 or 4-6-2/5.7 is to be installed in the
same space as the emergency switchboard. An indicator is to be mounted on the main switchboard
or in the machinery control room to indicate when these batteries are being discharged.
5.9.4 Interconnector Feeder Between Emergency and Main Switchboards
The emergency switchboard is to be supplied during normal operation from the main switchboard
by an interconnector feeder which is to be protected at the main switchboard against overload and
short circuit. The interconnector feeder is to be disconnected automatically at the emergency
switchboard upon failure of the main source of electrical power. Where the system is arranged for
feedback operation, the interconnector feeder is also to be protected at the emergency switchboard
against short circuit. In addition, the circuit protection device at the emergency switchboard on the
interconnector feeder is to trip to prevent overloading of the emergency generator.
5.9.5 Disconnection of Non-emergency Circuits
For ready availability of the emergency source of electrical power, arrangements are to be made,
where necessary, to disconnect automatically non-emergency circuits from the emergency switchboard
so that electrical power is to be available automatically to the emergency circuits.

5.11 Arrangements for Periodic Testing

Provision is to be made to enable the periodic testing of the complete emergency system and is to include
the testing of automatic starting arrangements.

5.13 Vessels Intended to Carry Passengers

See 5/13.5 of the ABS Guide for Building and Classing Passenger Vessels (Passenger Vessel Guide).

5.15 Starting Arrangements for Emergency Generator Sets

5.15.1 Cold Conditions
Emergency generating sets are to be capable of being readily started in their cold condition at a
temperature of 0°C (32°F). If this is impracticable or if lower temperatures are likely to be
encountered, heating arrangements are to be provided for ready starting of the generating sets.
5.15.2 Number of Starts
Each emergency generator that is arranged to be automatically started is to be equipped with approved
starting devices with a stored energy capability of at least three consecutive starts. Unless a second
independent means of starting is provided, the source of stored energy is to be protected to
preclude critical depletion by the automatic starting system, i.e., the automatic starting system is
only allowable for consumption of the stored energy source to a level that would still provide the
capability for starting the emergency generator upon intervention by personnel. In addition, a
second source of energy is to be provided for an additional three starts within 30 minutes unless
manual starting can be demonstrated to the Surveyor to be effective.
5.15.3 Charging of Stored Energy
The stored energy is to be maintained at all times, as follows:
5.15.3(a) Electrical and hydraulic starting systems are to be maintained from the emergency
switchboard;
5.15.3(b) Compressed air starting systems may be maintained by the main or auxiliary compressed
air receivers through a suitable non-return valve or by an emergency air compressor which, if
electrically driven, is supplied from the emergency switchboard;
5.15.3(c) All of these starting, charging and energy storing devices are to be located in the emergency
generator space. These devices are not to be used for any purpose other than the operation of the
emergency generating set. This does not preclude the supply to the air receiver of the emergency
generating set from the main or auxiliary compressed air system through the non-return valve
fitted in the emergency generator space.

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5.15.4 Manual Starting

Where automatic starting is not required, as per 4-6-2/5.5.2(b)ii), manual (hand) starting is permissible,
such as manual cranking, inertia starters, manually charged hydraulic accumulators or power charge
cartridges, where they can be demonstrated to the Surveyor as being effective.
When manual (hand) starting is not practicable, the requirements of 4-6-2/5.15.2 and 4-6-2/5.15.3
are to be complied with, except that starting may be manually initiated.

5.16 Use of Emergency Generator in Port (for Vessel 500 GT and Over) (2002)
Unless instructed otherwise by the Flag Administration, the emergency generator may be used during lay
time in port for supplying power to the vessel, provided the following requirements are complied with.
5.16.1 Arrangements for the Prime Mover
5.16.1(a) Fuel oil tank. The fuel oil tank for the prime mover is to be appropriately sized and
provided with a level alarm, which is to be set to alarm at a level where there is still sufficient fuel
oil capacity for the emergency services for the period of time required by 4-6-2/5.3.
5.16.1(b) Rating. The prime mover is to be rated for continuous service.
5.16.1(c) Filters. The prime mover is to be fitted with fuel oil and lubricating oil filters, in
accordance with 4-2-1/7.1 and 4-2-1/9.9, respectively.
5.16.1(d) Monitoring. The prime mover is to be fitted with alarms, displays and automatic
shutdown arrangements, as required in 4-7-4/Table 7, except that for fuel oil tank low-level alarm,
4-6-2/5.16.1(a) above is to apply instead. The displays and alarms are to be provided in the
centralized control station. Monitoring at the engineers’ quarters is to be provided as required in
4-7-4/31.
5.16.1(e) Fire detection. The emergency generator room is to be fitted with fire detectors. Where
the emergency generator is located in a space separated from the emergency switchboard, fire
detectors are to be located in each space. The fire detection and alarm system is to be in
compliance with 4-5-2/21 and may be a part of another system.
5.16.2 System Arrangements
5.16.2(a) Independence. The power supply circuits, including control and monitoring circuits,
for the use of the emergency generator in port are to be so arranged and protected that any
electrical fault, except for the emergency generator and the emergency switchboard, will not affect
the operation of the main and emergency services.
5.16.2(b) Changeover arrangement. Means are to be provided to readily change over to emergency
operation.
5.16.2(c) Overload prevention. The generator is to be safeguarded against overload by automatically
shedding such other loads so that the supply to the required emergency loads is always available.
5.16.3 Operational Instruction
Operational instructions, such as that on fuel oil tank level, harbor/seagoing mode changeover
arrangements, etc., are to be provided onboard. Before the vessel is underway, all valves, switches,
etc. are to be in the positions for their intended mode of operation of the emergency generator and
the emergency switchboard. Such instructions are to be distinctly posted at the emergency generator
room. Planned maintenance is to be carried out only while in port.

5.17 Alarms and Safeguards for Emergency Diesel Engines (2006)

5.17.1 Information to be Submitted
Information demonstrating compliance with these requirements is to be submitted for review. The
information is to include instructions to test the alarm and safety systems.

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5.17.2 Alarms and Safeguards

5.17.2(a) Alarms and safeguards are to be fitted in accordance with 4-6-2/Table 1.
5.17.2(b) The safety and alarm systems are to be designed to ‘fail safe’. The characteristics of the
‘fail safe’ operation are to be evaluated on the basis not only of the system and its associated
machinery, but also the complete installation, as well as the ship.
5.17.2(c) Regardless of the engine output, if shutdowns additional to those specified in 4-6-2/Table 1
are provided, except for the overspeed shutdown, they are to be automatically overridden when the
engine is in automatic or remote control mode during navigation.
5.17.2(d) The alarm system is to function in accordance with 4-7-2/5.1 through 4-7-2/5.13, with
additional requirements that grouped alarms are to be arranged on the bridge.
5.17.2(e) In addition to the fuel oil control from outside the space, a local means of engine
shutdown is to be provided.
5.17.2(f) Local indications of at least those parameters listed in 4-6-2/Table 1 are to be provided
within the same space as the diesel engines and are to remain operational in the event of failure of
the alarm and safety systems.

TABLE 1
Alarms and Safeguards for Emergency Diesel Engines
[See 4-6-2/5.17] (2009)
Systems Monitored Parameters A Auto Notes
Shut [ A = Alarm; x = apply ]
Down
Fuel oil A1 Leakage from pressure pipes x
Lubricating oil B1 Temperature – high x For engines having a power of 220 kW
or more.
B2 Lubricating oil pressure – low x
B3 (2009) Oil mist in crankcase, mist x (2009) For engines having a power of
concentration – high; or 2250 kW (3000 hp) and above or having
Bearing temperature – high; or a cylinder bore of more than 300 mm
(11.8 in.).
Alternative arrangements
See 4-2-1/7.2 of the Steel Vessel Rules.
Cooling medium C1 Pressure or flow – low x For engines having a power of 220 kW
or more.
C2 Temperature – high x
Engine D1 Overspeed activated x x For engines having a power of 220 kW
or more.

5.19 Vessels Less than 500 GT Having Electrical Plants of 75 kW and Above
5.19.1 General
This requirement is intended for vessels less than 500 GT having electrical plants of an aggregate
capacity of 75 kW and above. The emergency source of electrical power is to be self-contained
and readily available. 4-6-2/5.1.1, 4-6-2/5.1.2, 4-6-2/5.5 through 4-6-2/5.13 and 4-6-2/5.21 are
also applicable. Where the source of electrical power is a battery, see 4-6-3/3.7 for the installation.
For emergency lighting, a relay-controlled, battery-operated lantern is acceptable.
5.19.2 Capacity
The emergency source of electrical power is to be capable of supplying simultaneously at least the
following services for the period as specified herein:

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5.19.2(a) Emergency lighting for two hours:

i) At muster and embarkation stations for survival craft
ii) At survival craft, their launching appliances and the area of water into which they are
launched
5.19.2(b) Emergency lighting for six hours:
i) In all service and accommodation alleyways, stairways and exits, personnel elevators and
shafts;
ii) In the machinery spaces and main generating stations, including their control positions;
iii) In all control stations, machinery control rooms, and at each main and emergency
switchboard;
iv) At all stowage positions for firemen’s outfits;
v) At the steering gear; and
5.19.2(c) Navigation lights and other lights required by the International Regulation for Preventing
Collisions at Sea in force.
5.19.2(d) Radio installations for calling distress signals and rescue for six hours
5.19.2(e) Internal communication equipment, as required in an emergency for six hours.

5.21 Requirements by the Governmental Authority

Attention is directed to the requirements of the governmental authority of the country whose flag the vessel
flies for the emergency services and the accumulator batteries required in various types of vessels.

7 Distribution System

7.1 Ship Service Distribution System

7.1.1 General
Current-carrying parts with potential to earth are to be protected against accidental contact.
For recognized standard distribution systems, see 4-6-1/7. Separate feeders are to be provided for
essential and emergency services.
7.1.2 Method of Distribution
The output of the ship’s service generators may be supplied to the current consumers by way of
either branch system, meshed network system or ring main system. The cables of a ring-main or
other looped circuit (e.g., interconnecting section boards in a continuous circuit) are to be formed
of conductors having sufficient current-carrying and short-circuit capacity for any possible load
and supply configuration.
7.1.3 Through-feed Arrangements
The size of feeder conductors is to be uniform for the total length, but may be reduced beyond any
intermediate section board and distribution board, provided that the reduced size section of the
feeder is protected by an overload device.
7.1.4 Motor Control Center (2006)
Feeder cables from the main switchboard or any section board to the motor control centers are to
have a continuous current-carrying capacity not less than 100% of the sum of the nameplate ratings
of all of the motors supplied. Feeder cables of lesser current capacity are permitted, where the design
is such that connected consumers are not operated simultaneously, under any operating mode.

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7.1.5 Motor Branch Circuit

A separate circuit is to be provided for each fixed motor having a full-load current rating of 6 amperes
or more, and the conductors are to have a carrying capacity of not less than 100% of the motor
full-load current rating. No branch circuit is to have conductors less than 1.5 mm2 wire. Circuit-
disconnecting devices are to be provided for each motor branch circuit and to be in accordance
with 4-6-3/3.13.2 and 4-6-4/7.17.2.
7.1.6 Power Supply Through Transformers and Converters
7.1.6(a) Continuity of Supply (2004). Where transformers and/or converters form a part of the
vessel’s electrical system supplying essential services and services necessary for minimum comfortable
conditions of habitability, the number and capacity of the transformers and/or converters are to be
such that with any one transformer or converter or any one single phase of a transformer out of
service, the remaining transformers and/or converters or remaining phases of the transformer are
capable of supplying power to these loads under normal seagoing conditions.
7.1.6(b) Arrangements (2002). Each required transformer is to be located as a separate unit with
separate enclosure or equivalent, and is to be served by separate circuits on the primary and
secondary sides. Each of the secondary circuits is to be provided with a multipole isolating switch.
This multipole isolating switch is not to be installed on the transformer casing or its vicinity (in so
far as practicable), to preclude its damage by fire or other incident at the transformer. A circuit
breaker provided in the secondary circuit, in accordance with 4-6-2/9.15.1, will be acceptable in
lieu of a multipole isolating switch.
7.1.6(c) Transformers and Converters for Battery Charger (2004). Where batteries connected to
a single battery charger are the sole means of supplying DC power to equipment for essential
services, as defined in 4-6-1/3.3, failure of the single battery charger under normal operating conditions
should not result in total loss of these services once the batteries are depleted. In order to ensure
continuity of the power supply to such equipment, one of the following arrangements is to be provided:
i) Duplicate battery chargers; or
ii) A single battery charger and a transformer/rectifier (or switching converter) which is
independent of the battery charger, provided with a change-over switch; or
iii) Duplicate transformer/rectifier (or switching converter) units within a single battery charger,
provided with a change-over switch.
The above requirements are not applicable for the following:
• The equipment for the essential services which contains a single transformer/ rectifier with a
single AC power supply feeder to such equipment.
• The services which are not used continuously, such as battery chargers for engine starting
batteries, etc.
7.1.7 Ventilation System
Ventilation fans for cargo space are to have feeders separate from those for accommodations. See
also 4-6-2/19.1.1, 4-6-3/3.7.3, 4-6-6/1.13.1, 4-6-6/1.17.1, 4-6-6/5.3 and 4-6-6/7.3.1.
7.1.8 Heating Appliances
Each heater is to be connected to a separate final subcircuit. However, a group of up to 10 heaters
whose total current does not exceed 16 A may be connected to a single final subcircuit.
7.1.9 Circuits for Bunker or Cargo Space
All lighting and power circuits terminating in a bunker or cargo space are to be provided with a
multiple pole switch outside of the space for disconnecting such circuits.

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7.3 Hull Return System

7.3.1 General
7.3.1(a) All Vessels. The hull return system is not to be used for any purpose in a tanker, or for
power, heating or lighting in other type of vessels, except that the following systems may be used
for all types of vessels.
i) Impressed current cathodic protective systems;
ii) Limited and locally earthed systems, provided that any possible resulting current does not
flow directly through any hazardous areas; or
iii) Insulation level monitoring devices, provided the circulation current does not exceed 30 mA
under all possible conditions.
Current-carrying parts with potential to earth are to be protected against accidental contact.
7.3.1(b) Tankers. In addition to the above, also see 4-6-6/1.3.
7.3.2 Final Subcircuits and Earth Wires
Where the hull return system is used, all final subcircuits (i.e., all circuits fitted after the last protective
device) are to consist of two insulated wires, the hull return being achieved by connecting to the
hull one of the busbars of the distribution board from which they originate. The earth wires are to
be in accessible locations to permit their ready examination and to enable their disconnection for
testing of insulation.

7.5 Earthed Distribution Systems

System earthing is to be effected by means independent of any earthing arrangements of the non-current-
carrying parts. Means of disconnection is to be provided in the neutral earthing connection of each
generator so that the generator may be disconnected for maintenance. In distribution systems with neutral
earthed or for generators intended to be run with neutrals interconnected, the machines are to be designed
to avoid circulating currents exceeding the prescribed value. Transformer neutral is not to be earthed unless
all corresponding generator neutrals are disconnected from the system (e.g. during shore supply). See
4-6-3/7.5.2 and 4-6-6/1.3 for tankers.

7.7 External or Shore Power Supply Connection

7.7.1 General
Where arrangements are made for the supply of electricity from a source on shore or other external
source, a termination point is to be provided on the vessel for the reception of the flexible cable
from the external source. Fixed cables of adequate rating are to be provided between the termination
point and the main or emergency switchboard. Means for disconnecting the external or shore power
supply are to be provided at the receiving switchboard. See 4-6-2/9.11 for the protection of external
or shore power supply circuit.
7.7.2 Earthing Terminal
An earth terminal is to be provided for connecting the hull to an external earth.
7.7.3 Indicators
The external supply connection or shore connection is to be provided with a pilot lamp and a voltmeter
(and frequency meter for AC) at main or emergency switchboard to show energized status of the cable.
7.7.4 Polarity or Phase Sequence
Means are to be provided for checking the polarity (for DC) or the phase sequence (for three-phase
AC) of the incoming supply in relation to the vessel’s system.
7.7.5 Information Plate
An information plate is to be provided at or near the connection box giving full information on the
system of supply and the nominal voltage (and frequency if AC) of the vessel’s system and the
recommended procedure for carrying out the connection.

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7.7.6 Securing of Trailing Cable

Provision is to be made for securing the trailing cable to a framework to absorb stress on the electrical
terminals by catenary tension of the cable.

7.9 Harmonics (2006)

The total harmonic distortion (THD) in the voltage waveform in the distribution systems is not to exceed
5% and any single order harmonics not to exceed 3%. Other higher values may be accepted provided the
distribution equipment and consumers are designed to operate at the higher limits.

9 Circuit Protection System

9.1 System Design

9.1.1 General (1998)
Electrical installations are to be protected against accidental overload and short circuit, except
i) As permitted by 4-6-2/11.3,
ii) Where it is impracticable to do so, such as engine starting battery circuit, and
iii) Where by design, the installation is incapable of developing overload, in which case it may
be protected against short circuit only.
The protection is to be by automatic protective devices for:
i) Continued supply to remaining essential circuits in the event of a fault, and
ii) Minimizing the possibility of damage to the system and fire.
Three-phase, three-wire alternating current circuits are to be protected by a triple-pole circuit
breaker with three overload trips or by a triple-pole switch with a fuse in each phase. All branch
circuits are to be protected at distribution boards only, and any reduction in conductor sizes is to
be protected. Dual-voltage systems having an earthed neutral are not to have fuses in the neutral
conductor, but a circuit breaker which simultaneously opens all conductors may be installed, when
desired. In no case is the dual-voltage system to extend beyond the last distribution board.
9.1.2 Protection Against Short-circuit
9.1.2(a) Protective Devices. Protection against short-circuit is to be provided for each non-earthed
conductor by means of circuit breakers or fuses.
9.1.2(b) Rated Short-circuit Breaking Capacity. The rated short-circuit breaking capacity of every
protective device is not to be less than the maximum available fault current at that point. For
alternating current (AC), the rated short-circuit breaking capacity is not to be less than the root
mean square (r.m.s.) value of the AC component of the prospective short-circuit current at the
point of application. The circuit breaker is to be able to break any current having an AC component
not exceeding its rated breaking capacity, whatever the inherent direct current (DC) component
may be at the beginning of the interruption.
9.1.2(c) Rated Short-circuit Making Capacity. The rated short-circuit making capacity of every
switching device is to be adequate for maximum peak value of the prospective short-circuit current
at the point of installation. The circuit breaker is to be able to make the current corresponding to
its making capacity without opening within a time corresponding to the maximum time delay required.
9.1.3 Protection Against Overload
9.1.3(a) Circuit Breakers. Circuit breakers or other mechanical switching devices for overload
protection are to have a tripping characteristic (overload-trip time) adequate for the overload
capacity of all elements in the system to be protected and for any discrimination requirements.
9.1.3(b) Fuses. A fuse of greater than 320 amperes is not to be used for overload protection.

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9.1.3(c) Rating (2005). Fuse ratings and rating (or settings, if adjustable) of time-delay trip elements
of circuit breakers are not to exceed the rated current capacity of the conductor to be protected as
listed in 4-6-4/Table 10, except as otherwise permitted for generator motor, and transformer circuit
protection in 4-6-2/9.3, 4-6-2/9.13 and 4-6-2/9.15. If the standard ratings or settings of overload
devices do not correspond to the rating or the setting allowed for conductors, the next higher
standard rating or setting may be used, provided that it does not exceed 150% of the allowable
current carrying capacity of the conductor, where permitted by the Standard to which the feeder
cables have been constructed. Except as otherwise permitted for motor and transformer branch-
circuit protection, adjustable-trip circuit breakers of the time-delay or instantaneous type are to be
set to operate at not more than 150% of the rated capacity of the conductor to be protected.
9.1.3(d) Indication. The rating or setting of the overload protective device for each circuit is to
be permanently indicated at the location of the protective device.
9.1.4 Back-up Protection (2011)
9.1.4(a) Back-up Fuse Arrangements. Circuit breakers having breaking and/or making capacities
less than the prospective short-circuit current at the point of application will be permitted, provided
that such circuit breakers are backed-up by fuses which have sufficient short-circuit capacity for
that application. The fuse is to be specifically designed for back-up combinations with the circuit
breaker, and the maximum fault rating for the combination is to be provided.
9.1.4(b) Cascade Protection. Cascade protection may be permitted, subject to special consideration.
Such special consideration is not intended for new construction vessels, however may be granted
when modifications are performed to existing vessels. The cascade protection is to be arranged
such that the combination of circuit protective devices has sufficient short-circuit breaking
capacity at the point of application [see 4-6-2/9.1.2(b)]. All circuit protective devices are to
comply with the requirements for making capacity [see 4-6-2/9.1.2(c)]. Cascade protection is not
to be used for circuits of primary essential services. Where cascade protection is used for circuits
of secondary essential services, such services are to be duplicated, provided with means of
automatic transfer and the automatic transfer is to alarm at a manned location. Cascade protection
may be used for circuits of non-essential services.
9.1.5 Coordinated Tripping
Coordinated tripping is to be provided between generator, bus tie, bus feeder and feeder protective
devices. See also 4-6-2/9.3.2 and 4-6-2/9.7.1. Except for cascade system (backup protection) in
4-6-2/9.1.4, the coordinated tripping is also to be provided between feeder and branch-circuit protective
devices for essential services. Continuity of service to essential circuits under short-circuit conditions
is to be achieved by discrimination of the protective devices, as follows:
9.1.5(a) The tripping characteristics of protective devices in series is to be coordinated.
9.1.5(b) Only the protective device nearest to the fault is to open the circuit, except for the cascade
system (back-up protection), as specified in 4-6-2/9.1.4(a).
9.1.5(c) The protective devices are to be capable of carrying, without opening, a current not less
than the short-circuit current at the point of application for a time corresponding to the opening of
the breaker, increased by the time delay required for discrimination.

9.3 Protection for Generators

9.3.1 General
Generators of less than 25 kW not arranged for parallel operation may be protected by fuses. Any
generators arranged for parallel operation and all generators of 25 kW and over are to be protected
by a trip-free circuit breaker whose trip settings are not to exceed the thermal withstand capacity
of the generator. The long-time over-current protection is not to exceed 15% above either the full-
load rating of continuous rated machines or the overload rating of special-rated machines. The
shutting down of the prime mover is to cause the tripping of the ship service generator circuit breaker.

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9.3.2 Trip Setting for Coordination (2008)

The instantaneous and short-time overcurrent trips of the generators are to be set at the lowest
values of current and time which will coordinate with the trip settings of feeder circuit breakers.
See also 4-6-2/9.1.5, 4-6-2/9.5.1, and 4-6-2/9.5.2(a).
9.3.3 Load-shedding Arrangements (2004)
9.3.3(a) Provision for Load Shedding Arrangements. In order to safeguard continuity of the electrical
power supply, automatic load-shedding arrangements or other equivalent arrangements are to be
provided:
i) Where only one generating set is normally used to supply power for propulsion and steering
of the vessel, and a possibility exists that due to the switching on of additional loads, whether
manually or automatically initiated, the total load exceeds the rated generator capacity of
the running generator, or
ii) Where electrical power is normally supplied by more than one generator set simultaneously
in parallel operation for propulsion and steering of the vessel, upon the failure of one of
the parallel running generators, the total connected load exceeds the total capacity of the
remaining generator(s).
9.3.3(b) Services not Allowed for Shedding. Automatic load-shedding arrangements or other
equivalent arrangements are not to automatically disconnect the following services. See 4-6-1/3.3
for the definition of essential services.
i) Primary essential services that, when disconnected, will cause immediate disruption to
propulsion and maneuvering of the vessel,
ii) Emergency services as listed in 4-6-2/5.3, and
iii) Secondary essential services that, when disconnected, will:
• cause immediate disruption of systems required for safety and navigation of the vessel,
such as:
Lighting systems,
Navigation lights, aids and signals,
Internal communication systems required by 4-6-2/15, etc.
• prevent services necessary for safety from being immediately reconnected when the
power supply is restored to its normal operating conditions, such as:
Fire pumps, and other fire extinguishing medium pumps,
Bilge pumps,
Ventilation fans for engine and boiler rooms
9.3.4 Emergency Generator
The emergency generator is also to comply with 4-6-2/9.1, 4-6-3/9.3, 4-6-2/9.5 and 4-6-2/9.7, where
applicable. See also 4-6-2/5.9.

9.5 Protection for Alternating-current (AC) Generators

9.5.1 Short-time Delay Trip (2008)
Short-time delay trips are to be provided with circuit breakers for AC generators. See also 4-6-2/9.3.2.
The current setting of the short time delay trip is to be less than the steady state short-circuit current
of the generator.
For generators with a capacity of less than 200 kW having prime movers such as diesel engines or
gas turbines which operate independently of the electrical system, consideration may be given to
omission of short-time delay trips if instantaneous trips and long time overcurrent protection (see
4-6-2/9.3.1) are provided. When the short time delay trips are omitted, the thermal withstand capacity
of the generator is to be greater than the steady state short-circuit current of the generator, until
activation of the tripping system.

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9.5.2 Parallel Operation

Where AC generators are arranged for parallel operation with other AC generators, the following
protective devices are to be provided.
9.5.2(a) Instantaneous Trip (2008). Instantaneous trips are to be installed and set in excess of the
maximum short-circuit contribution of the individual generator where three or more generators are
arranged for parallel operation. See also 4-6-2/9.3.2.
9.5.2(b) Reverse Power Protection (2006). A time-delayed reverse active power protection or
other devices which provide adequate protection is to be provided. The setting of protective devices
is to be in the range of 2% to 6% of the rated power for turbines and in the range of 8% to 15% of
the rated power for diesel engines. A setting of less than 8% of the rated power of diesel engines
may be allowed with a suitable time delay recommended by the diesel engine manufacturer. A fall
of 50% in the applied voltage is not to render the reverse power protection inoperative, although it
may alter the setting to open the breaker within the above range.
9.5.2(c) Undervoltage Protection. Means are to be provided to prevent the generator circuit
breaker from closing if the generator is not generating and to open the same when the generator
voltage collapses.
In the case of an undervoltage release provided for this purpose, the operation is to be instantaneous
when preventing closure of the breaker, but is to be delayed for discrimination purposes when
tripping a breaker.

9.7 Protection for Direct Current (DC) Generators

9.7.1 Instantaneous Trip
DC generator circuit breakers are to be provided with an instantaneous trip set below the generator
maximum short-circuit current and are to coordinate with the trip settings of feeder circuit breakers
supplied by the generator.
9.7.2 Parallel Operation
9.7.2(a) Reverse Current Protection. DC generators arranged for parallel operation with other
DC generators or with an accumulator battery are to be provided with instantaneous or short-time
delayed reverse current protection. The setting of the protection devices is to be within the power
range specified by 4-6-2/9.5.2(a). When an equalizer connection is provided, the reverse current
device is to be connected on the pole opposite to the equalizer connection where the series
compound winding for the generator is connected. Reverse current protection is to be adequate to
deal effectively with reverse current conditions emanating from the distribution system (e.g.,
electric driven cargo winches).
9.7.2(b) Generator Ammeter Shunts. Generator ammeter shunts are to be so located that the
ammeters indicate total generator current.
9.7.2(c) Undervoltage Protection. Requirements for AC generator in 4-6-2/9.5.2(c) are also
applicable to DC generator.

9.9 Protection for Accumulator Batteries

Accumulator (storage) batteries, other than engine starting batteries, are to be protected against overload
and short circuits by devices placed as near as practicable to the batteries, but outside of the battery rooms,
lockers or boxes, except that the emergency batteries supplying essential services are to have short circuit
protection only. Fuses may be used for the protection of emergency lighting storage batteries instead of
circuit breakers up to and including 320 amperes rating. The charging equipment, except converters, for all
batteries with a voltage of more than 20% of the line voltage is to be provided with reverse current protection.

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9.11 Protection for External or Shore Power Supply

9.11.1 General
Where arrangements are made for the supply of electricity from a source on shore or other external
source, permanently fixed cables from the external supply or shore connection box to the main or
emergency switchboard are to be protected by fuses or circuit breakers located at the connection
box.
9.11.2 Interlocking Arrangement
Where the generator is not arranged for parallel operation with the external or shore power supply,
an interlocking arrangement is to be provided for the circuit breakers or disconnecting devices
between the generator and the external or shore power supply in order to safeguard from connecting
unlike power sources to the same bus.

9.13 Protection for Motor Branch Circuits

9.13.1 General
Trip elements of circuit breaker for starting and for short-circuit protection are to be in accordance
with 4-6-2/9.13.2 or 4-6-2/9.13.3, except that circuit breakers having only instantaneous trips may
be provided as part of the motor control center. Where circuit breakers having only instantaneous
trips are provided, the motor running protective device is to open all conductors, and the motor
controller is to be capable of opening the circuit without damage to itself resulting from a current
up to the setting of the circuit breaker. Circuit-disconnecting devices are to be provided for each
motor branch circuit and to be in accordance with 4-6-3/3.13.2 and 4-6-4/7.17.2.
9.13.2 Direct-current Motor Branch Circuits
The maximum fuse rating or the setting of the time-delay trip element is to be 150% of the full-
load rating of the motor served. If that rating or setting is not available, the next higher available
rating or setting may be used.
9.13.3 Alternating-current Motor Branch Circuits
The maximum fuse rating or setting of the trip element is to be the value stated below. If that
rating or setting is not available, the next higher available rating or setting may be used.

Rating or Setting in % Motor

Type of Motor
Full-load Current
Squirrel-cage and 250
Synchronous Full-voltage,
Reactor or Resistor-starting
Autotransformer Starting 200
Wound Rotor 150

When fuses are used to protect polyphase motor circuits, it is to be arranged to protect against
single-phasing.
The setting of magnetic instantaneous trips for short-circuit protection only is to exceed the transient
current inrush of the motor, and to be the standard value nearest to, but not less than, 10 times full-
load motor current.
9.13.4 Motor Running Protection (2005)
Running protection is to be provided for all motors having a power rating exceeding 0.5 kW,
except that such protection is not to be provided for steering gear motors (see 4-6-2/11.3). The
running protection is to be set between 100% and 125% of the motor rated current.
For athwartship thrusters having only instantaneous trips, a motor overload alarm in the wheelhouse
is acceptable in lieu of the motor running protection.

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9.13.5 Undervoltage Protection and Undervoltage Release (2011)

Undervoltage protection is to be provided for motors having power rating exceeding 0.5 kW (0.7 hp)
to prevent undesired restarting upon restoration of the normal voltage, after a stoppage due to a
low voltage condition or voltage failure condition.
Undervoltage release is to be provided for the following motors unless the automatic restart upon
restoration of the normal voltage will cause hazardous conditions:
i) Primary essential services (see 4-6-1/Table 4).
ii) Only those secondary essential services (see 4-6-1/Table 5) necessary for safety, such as:
• Fire pumps and other fire extinguishing medium pumps.
• Ventilating fans for engine and boiler rooms where they may prevent the normal
operation of the propulsion machinery (See Note 1 below)
Special attention is to be paid to the starting currents due to a group of motors with undervoltage
release controllers being restarted automatically upon restoration of the normal voltage. Means
such as sequential starting is to be provided to limit excessive starting current, where necessary.
Note 1: Undervoltage protection is to be provided for ventilation fans for engine and boiler room, which are
supplied by an emergency source of power for the purpose of removing smoke from the space after a fire
has been extinguished.

9.15 Protection for Transformer Circuits

9.15.1 Setting of Overcurrent Device
Each power and lighting transformer feeder is to be protected by an overcurrent device rated or set
at a value not more than 125% of rated primary current. When a transformer is provided with an
overcurrent device in the secondary circuit rated or set at not more than 125% of rated secondary
current, the feeder overcurrent device may be rated or set at a value less than 250% of the rated
primary current.
9.15.2 Parallel Operation (2006)
When the transformers are arranged for parallel operation, means are to be provided to disconnect
the transformer from the secondary circuit. Where power can be fed into secondary windings,
short-circuit protection (i.e., short-time delay trips) is to be provided in the secondary connections.
In addition, when the disconnecting device in primary side of the transformer is opened due to any
reason (e.g., the short-circuit protection, overload protection, or manual operation for opening),
the disconnecting device in the secondary side of the transformer is to be arranged to open the
circuit automatically.

9.17 Protection for Meters, Pilot Lamps and Control Circuits

Indicating and measuring devices are to be protected by means of fuses or current limiting devices. For
devices such as voltage regulators where interruption of the circuit may have serious consequences, fuses
are not to be used. If fuses are not used, means are to be provided to prevent fire in the unprotected part of
installation. Fuses are to be placed as near as possible to the tapping from the supply.

11 System for Steering Gear

11.1 Power Supply Feeder

Each electric or electro-hydraulic steering gear is to be served by at least two exclusive circuits fed directly
from the main switchboard. However, one of the circuits may be supplied through the emergency switchboard.
An auxiliary electric or electro-hydraulic steering gear associated with a main electric or electro-hydraulic
steering gear may be connected to one of the circuits supplying this main steering gear. The circuits supplying
an electric or electro-hydraulic steering gear are to have adequate rating for supplying all motors, control
system and instrumentation which are normally connected to them and operated simultaneously. The
circuits are to be separated throughout their length as widely as is practicable.

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11.3 Protection for Steering Gear Circuit

11.3.1 Short Circuit Protection
Each steering gear feeder is to be provided with short-circuit protection which is to be located at
the main or emergency switchboard. Long term overcurrent protection is not to be provided for
steering gear motors.
11.3.1(a) Direct Current (DC) Motors. For DC motors, the feeder circuit breaker is to be set to
trip instantaneously at not less than 300% and not more than 375% of the rated full-load current of
the steering-gear motor, except that the feeder circuit breaker on the emergency switchboard may
be set to trip at not less than 200%.
11.3.1(b) Alternating Current (AC) Motors. For AC motors, the protection against excess current,
including starting current, if provided, is to be for not less than twice the full load current of the
motor or circuit so protected, and is to be arranged to permit the passage of the appropriate starting
currents.
11.3.1(c) Fuses as Motor-feeder Protection. The use of fuses instead of circuit breakers for steering
gear motor feeder short-circuit protection is not permitted.
11.3.1(d) Control System Power Supply Circuit. The power supply circuit for steering gear control
system is to be provided with short circuit protection only. See also 4-3-3/11.5.
11.3.2 Undervoltage Release
Power unit motor controllers and other automatic motor controllers are to be fitted with undervoltage
release.

11.5 Emergency Power Supply

Where the rudder stock is required by 3-2-11/7.1 to be over 230 mm (9 in.) diameter using Ks = 1.0 in way
of the tiller, excluding strengthening for navigation in ice, an alternative power supply, sufficient at least to
supply the steering gear power unit and also its associated control system and rudder angle indicator, is to
be provided automatically within 45 seconds either from the emergency source of electrical power or from
an independent source of power located in the steering gear compartment. The steering gear power unit
under alternative power supply is to be capable of moving the rudder from 15 degrees on one side to 15
degrees on the other side in not more than 60 seconds with the vessel at the summer draft while running at
one half the maximum speed ahead or 7 knots, whichever is the greater. The alternative power supply is to
have a capacity for at least 10 minutes of continuous operation. See 4-6-2/5.3.5.

11.7 Controls, Instrumentation, and Alarms

See 4-3-3/11.

13 Lighting and Navigation Light Systems

13.1 Lighting System

13.1.1 Main Lighting System
A main electric lighting system is to provide illumination throughout those parts of the vessel
normally accessible to and used by passengers or crew. It is to be supplied from the main source
of electrical power.
13.1.2 System Arrangement
13.1.2(a) Main Lighting System. The arrangement of the main electric lighting system is to be
such that a fire or other casualty in spaces containing the main source of electrical power, associated
transforming equipment, if any, the main switchboard and the main lighting switchboard will not
render the emergency electric lighting system required by 4-6-2/5.3.2 of this Section or 5/13.5.3 of
the Passenger Vessel Guide inoperative.

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13.1.2(b) Emergency Lighting System. The arrangement of the emergency electric lighting system
is to be such that a fire or other casualty in spaces containing the emergency source of electrical
power, associated transforming equipment, if any, the emergency switchboard and the emergency
lighting switchboard will not render the main electric lighting system required by 4-6-2/13.1.1
inoperative.
13.1.3 Lighting Circuits
13.1.3(a) Machinery Space and Accommodation Spaces (2006). In spaces such as:
• Public spaces;
• Category A machinery spaces;
• Galleys;
• Corridors;
• Stairways leading to boat-decks, including stairtowers and escape trunks;
there is to be more than one final sub-circuit for lighting, one of which may be supplied from the
emergency switchboard in such a way that failure of any one circuit does not leave these spaces in
darkness.
13.1.3(b) Cargo Spaces. Fixed lighting circuits in cargo spaces are to be controlled by multipole-
linked switches situated outside of the cargo spaces. Means are to be provided on the multipole
linked switches to indicate the live status of circuits.
13.1.4 Protection for Lighting Circuits
Lighting circuits are to be protected against overload and short-circuit. Overload protective
devices are to be rated or set at not more than 30 amperes. The connected load is not to exceed the
lesser of the rated current carrying capacity of the conductor or 80% of the overload protective
device rating or setting. The control switches are to be rated for the load controlled.

13.3 Navigation Light System

13.3.1 Feeders
The masthead, side and stern lights are to be separately connected to a distribution board reserved
for navigation lights, placed in an accessible position on the bridge, and connected directly or through
transformers to the main or emergency switchboard. These lights are to be fitted with duplicate
lamps or other dual light sources and are to be controlled by an indicator panel. Provision is to be
made on the bridge for the navigation lights to be transferred to an alternative supply. See
4-6-2/5.3.2(c) for power supply.
13.3.2 Navigation Light Indicator
Each navigation light, as listed in 4-6-2/13.3.1, is to be provided with an indicator panel which
gives audible and/or visual warning automatically in the event of extinction of the light. If an
audible device is used, it is to be connected to a separate source of supply, for example, a primary
or accumulator (storage) battery. If a visual signal is used which is connected in series with the
navigation light, means are to be provided to prevent the extinction of the navigation light due to
failure of the visual signal. A means for disconnection of each navigation light circuit is to be
provided at the indicator panel.
13.3.3 Protection (1998)
Each navigation light, as listed in 4-6-2/13.3.1, is to be protected by a fuse or circuit breaker in
each insulated pole. Similarly, the navigation light indicator panel is to be provided with a fused-
feeder disconnect double-pole switch or double-pole circuit breaker which may be fitted on the
distribution board or the indicator panel. The rating of the fuses or circuit breaker setting is to be
at least twice that of the largest branch fuse or the circuit breaker setting and greater than the
maximum panel load.

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15 Interior Communication Systems

15.1 Navigation Bridge

15.1.1 General
At least two independent means are to be provided for communicating orders from the navigation
bridge to the position in the machinery space or in the control room from which the speed and
direction of thrust of the propellers are normally controlled. Appropriate means of communication
are to be provided to any other positions from which the main propulsion machinery may be
controlled. See 4-6-2/5.3.3(b) for power supply.
15.1.2 Engine Order Telegraph
One of the communicating means between the navigation bridge and the main propulsion control
position is to be an engine room telegraph which provides visual indication of the orders and
responses both in the machinery space and on the navigation bridge. Final sub-circuit for power
supply to this system is to be independent of other electrical systems and control, monitoring and
alarm systems. See 4-6-2/5.3.3(b) for power supply. Communication network and power supply
circuit for this may be combined with the engine order telegraph system specified in 4-6-2/15.3.
For vessels less than 500 GT, an engine order telegraph need not be provided if the propulsion
plant is controlled entirely from the navigation bridge with no means of normal engine control
from the engine room.

15.3 Main Propulsion Control Stations

A common talking means of voice communication and calling or engine order telegraph repeater is to be
provided between the main propulsion control station and local control positions for main propulsion
engines and controllable pitch propellers. Voice communication systems are to provide the capability of
carrying on a conversation while the vessel is being navigated. Final sub-circuit for power supply to these
are to be independent of other electrical systems and the control, monitoring and alarm systems.
Communication network and power supply circuit for the voice communication system may be combined
with the system required in 4-6-2/15.5.

15.5 Voice Communications

15.5.1 Propulsion and Steering Control Stations
A common talking means of voice communication and calling is to be provided between the
navigation bridge, main propulsion control station and the steering gear compartment so that the
simultaneous talking among these spaces is possible at all times and the calling to these spaces is
always possible even if the line is busy.
15.5.2 Elevator
Where an elevator is installed, a telephone is to be permanently installed in all cars and connected
to a continuously manned area. The telephone may be sound powered, battery operated or electrically
powered from the emergency source of power.
15.5.3 Independence of Power Supply Circuit
Final sub-circuit for power supply to these voice communication systems is to be independent of other
electrical systems and control, monitoring and alarm systems. See 4-6-2/5.3.3(b) for power supply.

15.7 Emergency and Interior-communication Switchboard

Emergency and interior-communication switchboards, when fitted, are to comply with the applicable parts
of 4-6-4/7, and attention is directed to the requirements of the governmental authority whose flag the vessel
flies.

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15.9 Public Address System (1 July 1998)

Vessels with the keel laid or in similar stage of construction on or after 1 July 1998 are to meet the following
requirements. Where a public address system is provided to supplement the general emergency alarm
required by 4-6-2/17.1.1, the public address system is to comply with subparagraphs 4-6-2/15.9.1 through
4-6-2/15.9.3, as follows:
15.9.1
The system is to be a loud speaker installation enabling the broadcast of messages to all spaces
where crew members or passengers, or both, are normally present, and to muster stations. The
system is to provide for the broadcast of messages from the navigation bridge and other places
onboard, as may be required by ABS, with an override function so that all emergency messages
may be broadcast if any loudspeaker in the spaces concerned has been turned off, its volume has
been turned down or the public address system is in use for other purposes.
The system is to be installed with acoustic marginal conditions and is not to require any action
from the addressee. The system is to be protected against unauthorized use.
15.9.2
With the vessel underway in normal conditions, the minimum sound pressure levels for broadcasting
emergency announcements in interior spaces are to be 75 dB (A) and at least 20 dB (A) above the
corresponding speech interference level.
15.9.3
The system is to be connected to the emergency source of power.
For passenger vessels, see 5/13.15 of the Passenger Vessel Guide.
15.9.4 (2006)
Where a single system serves for both public address and general emergency alarm functions, the
system is to be arranged so that a single failure is not to cause the loss of both systems and is to
minimize the effect of a single failure. The major system components, such as power supply unit,
amplifier, alarm tone generator, etc., are to be duplicated.
For cargo vessels, the coverage provided by the arrangement of the system loops and speakers is
to be such that after a single failure, the announcements and alarms are still audible in all spaces.
Duplication of system loops and speakers in each room or space is not required provided the
announcements and alarms are still audible in all spaces.
For passenger vessels, a single system serving for both public address and general emergency alarm
functions would still be required to have at least two loops sufficiently separated throughout their
length with two separate and independent amplifiers. See 5/13.15ii) of the Passenger Vessel Guide.

17 Manually Operated Alarms

17.1 General Emergency Alarm System (1 July 1998)

17.1.1 General
Each vessel over 100 GT is to be fitted with a general emergency alarm system, complying with
the requirements of 4-6-2/17.1.2, to summon crew to muster stations and initiate the actions
included in the muster list. The system is to be supplemented by either a public address system, in
accordance with 4-6-2/15.9, or other suitable means of communication. Any entertainment sound
system is to be automatically turned off when the general emergency alarm is activated. For
passenger vessels, see also 5/13.13 and 5/13.15 of the Passenger Vessel Guide.

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17.1.2 System Requirements (2009)

17.1.2(a) The general emergency alarm system is to be capable of sounding the general emergency
alarm signal consisting of seven or more short blasts followed by one long blast on the ship’s
whistle or siren and additionally on an electrically operated bell or klaxon or other equivalent warning
system, which is to be powered from the vessel’s main supply and the emergency source of
electrical power required by 4-6-2/5.
17.1.2(b) There are to be not less than two sources of power supply for the electrical equipment
used in the operation of the General Emergency Alarm System, one of which is to be from the
emergency switchboard and the other from the main switchboard. The supply is to be provided by
separate feeders reserved solely for that purpose. Such feeders are to run to an automatic change-
over switch situated in, or adjacent to, the main general emergency alarm control panel.
17.1.2(c) An alarm is to be provided to indicate when there is a loss of power in any one of the
feeders required by 4-6-2/17.1.2(b).
17.1.2(d) As an alternative to two feeders as described in 4-6-2/17.1.2(b), a battery may be considered
as one of the required sources, provided the battery has the capacity of at least 30 minutes of
continuous operation for alarming and 18 hours in standby. A low voltage alarm for the battery
and the battery charger output is to be provided. The battery charger is to be supplied from the
emergency switchboard.
17.1.2(e) The system is to be capable of operation from the navigation bridge and, except for
ship’s whistle, also from other strategic points. The system is to be audible throughout all of the
accommodation and normal crew working spaces. The alarm is to continue to function after it has
been triggered until it is manually turned off or is temporarily interrupted by a message on the
public address system.
17.1.2(f) The minimum sound pressure levels for the emergency alarm tone in interior spaces are
to be 80 dB and at least 10 dB (A) above ambient noise levels existing during normal equipment
operation with the vessel underway in moderate weather. In cabins without a loud speaker installation,
an electrical alarm transducer is to be installed.
17.1.2(g) The sound pressure levels at the sleeping position in cabins and in cabin bathrooms are
to be at least 75 dB (A) and at least 10 dB (A) above ambient noise levels. (Refer to Code on
Alarms and Indicators adopted by IMO Resolution A.830 (19).)

17.3 Engineers’ Alarm (2007)

On vessels of 500 gross tons and over, intended for international voyages, an engineers’ alarm operable from
the centralized propulsion machinery control station in the engine room or at the propulsion machinery
local control position, as appropriate, is to be provided. It is to be audible in each engineer’s cabin, and its
sound pressure level is to comply with 4-6-2/17.1.2. See 4-6-2/5.3.3(e) for power supply.

17.5 Refrigerated Space Alarm

Fan and diffuser rooms serving subfreezing compartments are to be provided with a device capable of
activating an audible and visual alarm in a manned control center and operable from within the latter space
for the protection of personnel. See 4-6-2/5.3.3(e) for power supply.

17.7 Elevator
A device which will activate an audible and visual alarm in a manned control center is to be provided in all cars.
Such alarm system is to be independent of power and control systems of the elevator. See 4-6-2/5.3.3(e)
for power supply.

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19 Fire Protection and Fire Detection Systems

19.1 Emergency Stop

19.1.1 Ventilation System
19.1.1(a) General. All electrical ventilation systems are to be provided with means for stopping
the motors in case of fire or other emergency. These requirements do not apply to closed re-circulating
systems within a single space. See also 4-6-6/1.13.1(b), 4-6-6/5.3.6 and 4-5-1/5.1.
19.1.1(b) Machinery Space Ventilation (2005). Machinery-space ventilation is to be provided
with means for stopping the ventilation fans, which is to be located in the passageway leading to,
but outside of the space, or at the fire-fighting station, if fitted. The means for stopping the power
ventilation serving machinery spaces is to be entirely separate from the means for stopping the
ventilation of other spaces.
In the case of vessels for which SOLAS is applicable, the means of stopping the ventilation fans is
to be grouped so as to be operable from two positions, one of which is to be located outside the space.
19.1.1(c) Ventilation Other Than Machinery Space. A control station for all other ventilation systems
is to be located in a centralized fire-fighting location or navigation bridge, or in an accessible position
leading to, but outside of, the space ventilated.
19.1.2 Other Auxiliaries (2009)
See 4-4-4/1.5 and 4-5-1/5.3 for emergency tripping and emergency stop for other auxiliaries, such
as forced and induced draft fans, fuel oil units, lubricating oil service pumps, thermal oil circulating
pumps and oil separators (purifiers).

19.3 Fire Detection and Alarm System

See 4-5-2/21, 4-5-2/27, 4-5-2/29.1 and 4-7-4/29.5.

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4
CHAPTER 6 Electrical Installations

SECTION 3 Shipboard Installation

1 Plans and Data to be Submitted

1.1 Booklet of Standard Details

A booklet of the standard wiring practices and details, including such items as cable supports, earthing
details, bulkhead and deck penetrations, cable joints and sealing, cable splicing, watertight and explosion-
proof connections to equipment, earthing and bonding connections, etc., as applicable, is to be submitted.
Where cable penetration methods for A- or B-class decks or bulkheads are shown, evidence of approval by
an Administration signatory to 1974 SOLAS as amended is also to be submitted.

1.3 Arrangement of Electrical Equipment

A general arrangement plan showing the location of at least the following electrical equipment is to be
submitted for review.
• Generator, Essential Motor and Transformer
• Battery
• Switchboard, Battery Charger and Motor Controller
• Emergency Lighting Fixture
• General Emergency Alarm Device and Alarm Actuator
• Detector, Manual Call Point and Alarm Panel for Fire Detection and Alarm System
• Certified-safe Type Equipment
Where cable splices or cable junction boxes are provided, locations of the splices and cable junction boxes
together with the information of their services are also to be submitted for review.

1.5 Electrical Equipment in Hazardous Areas

A plan showing hazardous areas is to be submitted for review together with the following:
• A list/booklet of intended electrical equipment in the indicated hazardous areas, including a description
of the equipment, applicable degree of protection and ratings. See 4-6-3/11.3.
• For intrinsically-safe systems, also wiring plans, installation instructions with any restrictions imposed
by the certification agency.
• Detail of installation for echo sounder, speed log and impressed current cathodic protection system
where located in these areas.
When the selection of the equipment has been finalized, a list/booklet identifying all equipment in the hazardous
areas, their method of protection (flameproof, intrinsically safe, etc.), rating (flammable gas group and
temperature class), manufacturer’s name, model number and evidence of certification is to be submitted for
review. A copy of this list/booklet is to be maintained onboard for future reference. See 4-6-3/11.1.4.

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1.7 Maintenance Schedule of Batteries (2008)

Maintenance Schedule of batteries for essential and emergency services. See 4-6-3/3.7.5.

3 Equipment Installation and Arrangement

3.1 General Consideration

3.1.1 Equipment Location (2006)
3.1.1(a) General. Electrical equipment is to be so placed or protected as to minimize the
probability of mechanical injury or damage from the accumulation of dust, oil vapors, steam or
dripping liquids. Equipment liable to generate arc is to be ventilated or placed in a compartment
ventilated to avoid accumulation of flammable gases, acid fumes and oil vapors. See 4-6-3/Table 1
for the required degree of protection for various locations.
3.1.1(b) Equipment in Areas Protected by Local Fixed Pressure Water-spraying or Local Water-mist
Fire Extinguishing System in Machinery Spaces. Unless it is essential for safety or operational
purposes, electrical and electronic equipment is not to be located within areas protected by Local
Fixed Pressure Water-spraying or Water-mist Fire Extinguishing System and in adjacent areas
where water may extend.
The electrical and electronic equipment located within areas protected by Local Fixed Pressure
Water-spraying or Water-mist Fire Extinguishing System and those within adjacent areas exposed
to direct spray are to have a degree of protection not less than IP44. See 4-6-3/Figure 1.
Electrical and electronic equipment within adjacent areas not exposed to direct spray may have a
lower degree of protection provided evidence of suitability for use in these areas is submitted
taking into account the design and equipment layout, e.g., position of inlet ventilation openings,
filters, baffles, etc. to prevent or restrict the ingress of water mist/spray into the equipment. The
cooling airflow for the equipment is to be assured.
Note:
Additional precautions may be required to be taken with respect to:
a. Tracking as the result of water entering the equipment
b. Potential damage as the result of residual salts from sea water systems
c. High voltage installations
d. Personnel protection against electric shock
Equipment may require maintenance after being subjected to water mist/spray.

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FIGURE 1
Example of Protected Area, Adjacent Area of Direct Spray
and Adjacent Area where Water May Extend (2006)

Water-spray or Water-mist Nozzle

Diesel Engine for Generator

Generator

Adjacent area where water may

extend: Evidence of suitability for
lower than IP44 is required.

Adjacent area of direct spray: IP44

Protected Area: IP44

3.1.2 Protection from Bilge Water

All generators, motors and electric couplings are to be so arranged that they cannot be damaged by
bilge water; and, if necessary, a watertight coaming is to be provided to form a well around the
base of such equipment with provision for removing water from the well.
3.1.3 Accessibility
The design and arrangement of electrical apparatus is to provide accessibility to parts requiring
inspection or adjustment. Armature and field coils, rotors and revolving fields are to be removable
and where air ducts are used, there are to be means of access.

3.3 Generators
All generators are to be located with their shafts in a fore-and-aft direction on the vessel and are to operate
satisfactorily in accordance with the inclination requirements of 4-1-1/17. Where it is not practicable to
mount the generators with the armature shafts in the fore-and-aft direction, their lubrication will require
special consideration. Provision is to be made to prevent oil or oil vapor from passing into the machine
windings.

3.5 Ship Service Motors

3.5.1 General
Motors for use in the machinery space above the floor plate or spaces where subject to mechanical
injury or dripping of oil or water are to have an enclosure of at least IP22 protection, in accordance
with 4-6-3/Table 1. However, where they are protected by drip covers, they may have an enclosure
of a lower protection grade than IP22. The motors having a protection enclosure of IP22 or lower
are to be installed at a location high enough to avoid bilge water. Motors below the level of the
floor plates are to have an enclosure of at least IP44 protection. Where motors intended for service
at sea are not mounted with the rotor shafts in the fore-and-aft direction, the type of bearing and
lubrication will require special consideration.

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3.5.2 Pump Motors

Motors for operating plunger and close-coupled pumps are to have the driving end entirely enclosed
or designed to prevent leakage from entering the motor.
3.5.3 Motors on Weather Decks
Motors for use on weather decks are to have an enclosure of at least IP56 protection or are to be
enclosed in watertight housings.
3.5.4 Motors Below Decks
Motors below decks are to be installed at a location as dry as practicable and away from steam,
water and oil piping.

3.7 Accumulator Batteries

3.7.1 General
The following requirements are applicable to permanently installed power, control and monitoring
storage batteries of acid or alkaline types. Batteries are to be so arranged that the trays are accessible
and provided with not less than 254 mm (10 in.) headroom. Where a relief valve is provided for
discharging excessive gas due to overcharge, arrangements are to be made for releasing the gas to
the weather deck away from any source of ignition.
3.7.2 Battery Installation and Arrangements
3.7.2(a) Large Batteries (2008). Large storage batteries, those connected to a charging device
with an output of more than 2 kW, are to be installed in a room assigned to the battery only, but
may be installed in a deck locker if such a room is not available. No electrical equipment is to be
installed in the battery rooms unless essential for the operational purposes and certified safe for
battery room atmosphere. Electrical equipment installed in battery rooms may be any of the types
indicated in 4-6-3/11.1.1 and is to be IEC Publication 60079 group IIC class T1.
3.7.2(b) Moderate-size Batteries. Batteries of moderate size, those connected to a charging
device with a power output of 0.2 kW up to and including 2 kW, may be installed in the battery
room or may be installed in battery lockers or deck boxes in the emergency generator room, machinery
space or other suitable location. Cranking batteries are to be located as closely as possible to the
engine or engines served.
3.7.2(c) Small Batteries. Small batteries are to be installed in a battery box and may be located
as desired, except they are not to be located in sleeping quarters unless hermetically sealed.
3.7.2(d) Low-hydrogen-emission Battery Installations. A low-hydrogen-emission battery installation
with a battery charger having a charging rate of a large or moderate battery size installation may
be treated as a moderate or small battery installation, respectively, if the following are met:
i) Calculations under the worst case charging conditions are submitted that demonstrate that
the low-hydrogen-emission battery installation does not emit more hydrogen under similar
charging conditions than a bank of standard lead acid batteries supplied by a 2 kW charger
for a moderate battery installation or 0.2 kW charger for a small battery installation, and
ii) A warning notice is placed to notify maintenance personnel that additional batteries are
not to be installed, and batteries are only to be replaced by other batteries of the same or
lower hydrogen emission rate.
3.7.2(e) Battery Trays. Trays for batteries are to be chocked with wood strips or equivalent to prevent
movement, and each tray is to be fitted with nonabsorbent insulating supports on the bottom and
with similar spacer blocks at the sides or with equivalent provision to secure air-circulation space
all around each tray.
3.7.2(f) Identification of Battery Types. Lead-acid batteries and alkaline batteries, when placed
in the same battery compartment, are to be effectively identified as to type and segregated.

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3.7.3 Ventilation
3.7.3(a) Battery Rooms. Battery rooms are to be ventilated to avoid accumulation of flammable
gas. Natural ventilation may be employed if ducts are run directly from the top of the battery room
to the open air above.
If natural ventilation is impractical, mechanical exhaust ventilation is to be provided with fan intake
at the top of the room. Fans are to be of non-sparking construction in accordance with 4-6-3/11.7
and capable of completely changing the air in the battery room in not more than two minutes.
Alternatively, a lesser ventilation rate may be considered, provided that satisfactory calculations
are submitted substantiating that adequate ventilation is available to maintain the flammable gases
within the battery room to a level below the lower explosive limit (L.E.L.) at the maximum battery
charging current. Where the ventilation rate is based on low hydrogen emission type batteries, a
warning notice to this effect is to be provided in a visible place in the battery room. Openings for
air inlet are to be provided near the floor.
3.7.3(b) Battery Lockers. Battery lockers are to be ventilated, if practicable, similarly to battery
rooms by a duct led from the top of the locker to the open air or to an exhaust ventilation duct.
Louvers or equivalent are to be provided near the bottom for entrance of air.
3.7.3(c) Deck Boxes. Deck boxes are to be provided with a duct from the top of the box, terminating
in a goose neck, mushroom head or equivalent to prevent entrance of water. Holes for air inlet are
to be provided on at least two opposite sides of the box. The entire deck boxes, including openings
for ventilation, is to be weathertight to prevent entrance of spray or rain.
3.7.3(d) Small Battery Boxes. Boxes for small batteries require no ventilation other than openings
near the top to permit escape of gas.
3.7.4 Protection from Corrosion
The interiors of battery rooms, including the structural parts and shelves therein, as well as ventilation
inlets and outlets are to be painted with corrosion-resistant paint. Shelves in battery rooms or lockers
for acid batteries are to have a watertight lining of sheet lead not less than 1.6 mm (1/16 in.) on all
sides. For alkaline batteries, the shelves are to be similarly lined with steel not less than 0.8 mm
(1/32 in.) thick. Alternatively, a battery room may be fitted with a watertight lead pan, steel for
alkaline batteries, over the entire deck, carried up not less than 152 mm (6 in.) on all sides. Deck
boxes are to be lined in accordance with the above alternative method. Boxes for small batteries
are to be lined to a depth of 76 mm (3 in.), consistent with the methods described above.
3.7.5 Maintenance of Batteries (2008)
3.7.5(a) Maintenance Schedule of batteries. Where batteries are fitted for use for essential and
emergency services, a maintenance schedule of such batteries is to be provided and maintained.
The schedule is to include all batteries used for essential and emergency services, including system
batteries installed in battery rooms, battery lockers and deck boxes as well as batteries installed
within vendor supplied equipment. Examples of batteries included with equipment are:
• Computer equipment and programmable logic controllers (PLC) used in computer based systems
and programmable electronic systems, when used for essential or emergency services.
• Navigation equipment, such as the equipment required by SOLAS, Chapter V, Regulation 19.
The schedule is to be submitted for review and is to include at least the following information
regarding the batteries.
• Type and manufacturer’s type designation.
• Voltage and ampere-hour rating.
• Location.
• Equipment and/or system(s) served.
• Maintenance/replacement cycle dates.

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• Date(s) of last maintenance and/or replacement.

• For replacement batteries in storage, the date of manufacture and shelf life (See Note below)
Note: Shelf life is the duration of storage under specified conditions at the end of which a battery retains the
ability to give a specified performance.
3.7.5(b) Procedure of maintenance. Procedures are to be put in place to show that, where batteries
are replaced, they are to be of an equivalent performance type. Details of the schedule, procedures,
and the maintenance records are to be included in the ship’s safety management system and
integrated into the ship’s operational maintenance routine, as appropriate, which are to be verified
by the Surveyor.
3.7.6 Replacement of Batteries (2008)
Where a vented type battery (See Note 1) replaces a valve-regulated, sealed type battery (See Note 2),
the requirements in 4-6-3/3.7.2 and 4-6-3/3.7.3 are to be complied with on the basis of the charging
capacity.
Notes:
1 A vented battery is one in which the cells have a cover provided with an opening through which
products of electrolysis and evaporation are allowed to escape freely from the cells to atmosphere.
2 A valve-regulated battery is one in which cells are closed but have an arrangement (valve)
which allows the escape of gas if the internal pressure exceeds a predetermined value.

3.9 Switchboard
Switchboards are to be so arranged as to give easy access as may be needed to apparatus and equipment,
without danger to personnel. Switchboards are to be located in a dry place so as to provide a clear working
space of at least 914 mm (36 in.) at the front of the switchboard and a clearance of at least 610 mm (24 in.)
at the rear which may be reduced to 457 mm (18 in.) in way of stiffeners or frames, except that for
switchboards which are enclosed at the rear and are fully serviceable from the front, clearance at the rear
will not be required unless necessary for cooling. Switchboards are to be secured to a solid foundation.
They are to be self-supported or be braced to the bulkhead or the deck above. In case the last method is
used, means of bracing is to be flexible to allow deflection of the deck without buckling the assembly
structure.

3.11 Distribution Boards

3.11.1 Location and Protection (2004)
Distribution boards are to be located in accessible positions and not in such space as bunkers,
storerooms, cargo holds or compartments allotted alternately to passengers or cargo. Distribution
boards may be located behind panels/linings within accommodation spaces, including stairway
enclosures, without the need to categorize the space to a fire integrity standard, provided no provision
is made for storage. Distribution boards are to have approved noncombustible, non-hygroscopic
enclosures. Metal enclosures and all exposed metal parts in nonmetallic enclosures are to be
earthed to the vessel’s structure. All cases are to be of adequate mechanical strength.
3.11.2 Switchboard-type Distribution Boards
Distribution boards of the switchboard type, unless installed in machinery spaces or in compartments
assigned exclusively to electric equipment and accessible only to authorized personnel, are to be
completely enclosed or protected against accidental contact and unauthorized operation.
3.11.3 Safety-type Panels (1998)
If the method of operation demands the handling of switches by persons unfamiliar with electrical
equipment, the distribution board is to be of the safety type. This type of distribution board is to be
used for controlling branch lighting circuits. Dead front type panels are to be used where voltage
to earth is in excess of 50 volts DC or 50 volts AC r.m.s. between conductors.

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3.11.4 Lighting Distribution Boards (2005)

To prevent the simultaneous loss of main and emergency lighting distribution boards due to localized
fire or other casualty, these distribution boards are to be installed as widely apart as practicable in
the machinery spaces.
For spaces other than the machinery space (e.g. accommodation space, ro-ro cargo spaces, etc.), these
lighting distribution boards are to be installed at locations which are separated by a boundary wall.
Cables emanating from the main or emergency lighting switchboard to the main or emergency
lighting distribution board respectively are also to be installed as widely apart as practicable. See
also 4-6-2/13.1.2.

3.13 Motor Controllers and Control Centers

3.13.1 Location and Installation
Motor control centers are to be located in a dry place. Clear working space is to be provided around
motor control centers to enable doors to be fully opened and equipment removed for maintenance
and replacement. Motor control centers are to be secured to a solid foundation, be self-supported
or be braced to the bulkhead.
3.13.2 Disconnecting Arrangements
3.13.2(a) Device. Means are to be provided for disconnecting the motor and controller from all
supply conductors, except that a manually operated switch or circuit breaker may serve as both
controller and disconnecting means (see 4-6-4/7.17.2).
3.13.2(b) Location (1998). The disconnecting device may be in the same enclosure with the
controller or may be in a separate enclosure, and is to be externally operated. Except for remotely
controlled fire extinguishing purpose motors, the branch-circuit switch or circuit breaker on the
power-distribution board or switchboard may serve as the disconnect device if in the same
compartment with the controller.
3.13.2(c) Locking Means (1998). If the disconnecting device is not within sight of both motor
and controller, or if it is more than 15.25 m (50 ft) from either, it is to be arranged for locking in
the open position. For remotely controlled fire extinguishing purpose motors, the locking means
are to be provided at the feeder circuit breaker for such motors.
3.13.2(d) Identification Plate. The disconnect switch, if not adjacent to the controller, is to be
provided with an identification plate.
3.13.2(e) Open and Close Indications. The disconnect device is to indicate by a position of the
handle, or otherwise, whether it is open or closed.
3.13.3 Indicating-light Circuits
Where indicating-light circuits are employed, their potential is to be limited to 150 volts if the
opening of the foregoing disconnecting devices does not de-energize the indicating circuit.

3.15 Resistors for Control Apparatus

The resistor is to be protected against corrosion either by rust-proofing or embedding in a protective
material. Resistors are to be located in well-ventilated compartments and are to be mounted with ample
clearances, about 305 mm (12 in.), to prevent excessive heating of adjacent vessel’s structure or dangerous
overheating of unprotected combustible material. The arrangement of the electrical equipment and wiring
located within these spaces is to be such as to prevent their exposure to ambient temperatures in excess of
that for which they have been designed.

3.17 Lighting Fixtures

Lighting fixtures are to be so arranged as to prevent temperature rises which could damage the cables and
wiring, and to prevent surrounding material from becoming excessively hot.

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3.19 Heating Equipment

Electric radiators, if used, are to be fixed in position and be so constructed as to reduce fire risks to a
minimum. Electric radiators of the exposed-element type are not to be used.

3.21 Magnetic Compasses

Precautions are to be taken in connection with apparatus and wiring in the vicinity of the magnetic
compass to prevent disturbance of the needle from external magnetic fields.

3.23 Portable Equipment and Outlets

Portable equipment are not to be used in cargo oil pump rooms or other hazardous areas nor are portable
lights to be used for berth lights in passenger accommodations or crew’s quarters.

3.25 Receptacles and Plugs of Different Ratings

Receptacles and plugs of different electrical ratings are not to be interchangeable. In cases where it is
necessary to use 230 volt portable equipment, the receptacles for their attachment are to be of a type which
will not permit attaching 115 volt equipment.

3.27 Installation Requirements for Recovery from Dead Ship Condition (2005)
Means are to be provided to ensure that machinery can be brought into operation from the dead ship condition
without external aid. See 4-1-1/19.
Where the emergency source of power is an emergency generator which complies with 4-6-2/5.15 and
4-6-2/3.1.3, this emergency generator may be used for restoring operation of the main propulsion plant,
boilers and auxiliary machinery.
Where there is no emergency generator installed, the arrangements for bringing main and auxiliary machinery
into operation are to be such that the initial charge of starting air or initial electrical power and any power
supplies for engine operation can be developed onboard ship without external aid. If for this purpose an
emergency air compressor or an electric generator is required, these units are to be powered by a hand-
starting oil engine or a hand-operated compressor.
The arrangements for bringing the main and auxiliary machinery into operation are to have a capacity such
that the starting energy and any power supplies for propulsion engine operation are available within 30 minutes
of a blackout condition.

3.29 Services Required to be Operable Under a Fire Condition (2008)

For the purpose of 4-6-3/5.17.2, services required to be operable under a fire condition include, but not
limited thereto, are the following:
i) Fire and general alarm system
ii) Fire extinguishing system including fire extinguishing medium release alarms
iii) Emergency Fire Pump
iv) Fire detection system
v) Control and power systems for all power operated fire doors and their status indicating systems
vi) Control and power systems for all power operated watertight doors and their status indicating
systems
vii) Emergency lighting
viii) Public address system
ix) Remote emergency stop/shutdown arrangement for systems which may support the propagation of
fire and/or explosion
x) For passenger vessels, see 5/13.7.2(b) of the Passenger Vessel Guide.

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3.31 High Fire Risk Areas (2008)

For the purpose of 4-6-3/5.17, the examples of the high fire risk areas are the following:
i) Machinery spaces as defined by 4-1-1/13.1 and 13.3
ii) Spaces containing fuel treatment equipment and other highly flammable substances
iii) Galley and pantries containing cooking appliances
iv) Laundry containing drying equipment
v) For passenger vessels, see 5/13.7.2(c) of the Passenger Vessel Guide.

5 Cable Installation

5.1 General Considerations

5.1.1 Continuity of Cabling
Electric cables are to be installed in continuous lengths between terminations at equipment or in
cable junction boxes. See 4-6-3/5.33. However, approved splices will be permitted at interfaces of
new construction modules, when necessary to extend existing circuits for a vessel undergoing repair
or alteration, and in certain cases to provide for cables of exceptional length (See 4-6-3/5.29).
5.1.2 Choice of Cables
The rated operating temperature of the insulating material is to be at least 10°C (18°F) higher than
the maximum ambient temperature likely to exist or to be produced in the space where the cable is
installed.
5.1.3 Cable Voltage Drop for New Installation
The cross-sectional area of conductors are to be so determined that the drop in voltage from the main
or emergency switchboard bus-bars to any and every point of the installation when the conductors
are carrying the maximum current under normal steady conditions of service will not exceed 6%
of the nominal voltage. For supplies from batteries with a voltage not exceeding 55 V, this figure
may be increased to 10%.
The above values are applicable under normal steady conditions. Under special conditions of short
duration, such as motor starting, higher voltage drops may be accepted, provided the installation is
capable of withstanding the effects of these higher voltage drops.
5.1.4 Restricted Location of Cabling
Cables and wiring are to be installed and supported in such a manner as to avoid chafing or other
damage. Cables are to be located with a view to avoiding, as far as practicable, spaces where excessive
heat and gases may be encountered, also spaces where they may be exposed to damage, such as
exposed sides of deckhouses. Cables are not to be installed in the bilge area unless protected from
bilge water. See also 4-6-6/1.9.3 for cables used for echo sounder, speed log and impressed current
cathodic protection system in hazardous area.
5.1.5 Means of Drainage from Cable Enclosures
Where cables are installed in a cable draw box and horizontal pipes or the equivalent used for
cable protection, means of drainage are to be provided.
5.1.6 High Voltage Cables
Cables serving systems above 1 kV are not to be bunched with cables serving systems of 1 kV and
below.

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5.1.7 Paint on Cables (2006)

Where paint or any other coating is systematically and intentionally applied on the electric cables,
it is to be established that the mechanical and fire performance properties of the cable are not
adversely affected.
In this regard:
i) Fire retardant property is to be confirmed to be in compliance with 4-6-4/13.1.2.
ii) It is to be confirmed that the paint and the solvent used will not cause damages to the
cable sheath, e.g., cracking.
Overspray on cables or painted exterior cables are not subject to the requirements of this section.
5.1.8 Cable Installation above High Voltage Switchgear and Control-gear (2006)
Where a pressure relief flap is provided for high voltage switchgear and high voltage control-gear,
the cables are not to be installed near and above this equipment in order to prevent the damage of
cables from the flare/flame released from the relief flap upon occurrence of short circuit in this
equipment.

5.3 Insulation Resistance for New Installation

Each power and each light circuit is to have an insulation resistance between conductors and between each
conductor and earth of not less than the following values.

Up to 5 amperes load 2 meg ohms

10 amperes load 1 meg ohm
25 amperes load 400,000 ohms
50 amperes load 250,000 ohms
100 amperes load 100,000 ohms
200 amperes load 50,000 ohms
Over 200 amperes load 25,000 ohms

If the above values are not obtained, any or all appliances connected to the circuit may be disconnected for
this test.

5.5 Protection for Electric-magnetic Induction

5.5.1 Multiple Conductor Cables
All phase conductors of alternating-current cables are to be contained within the same sheath in
order to avoid overheating due to induction by use of multiple conductor cables.
5.5.2 Single Conductor Cables (1999)
AC installations are to be carried out, as far as possible, in twin or multi-conductor cables. However,
when it is necessary to use single conductor cables in circuits rated in excess of 20 A, the
following arrangements are to be complied with:
5.5.2(a) Cables are supported on non-fragile insulators;
5.5.2(b) There are to be no magnetic materials between cables of a group; and
5.5.2(c) (1999) Where single conductor cables are run in bunches, each group of cables is to
comprise 360 electrical degrees. To this end, in three-phase circuits, single conductor cable runs
of 30 m (100 ft) or longer and having a cross-sectional area of 185 mm2 (365,005 circ. mils) or more
are to be transposed throughout the length at intervals not exceeding 15 m (50 ft) in order to equalize
to some degree the impedance of the three phase circuits. Alternatively, such cables may be installed
in trefoil formation.
See 4-6-4/13.1.5 for armor.

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5.5.3 Non-shielded Signal Cables

Except for fiber optic cables, non-shielded signal cables for automation and control systems essential
for the safe operation of the vessel which may be affected by electromagnetic interference are not
to be run in the same bunch with power or lighting cables.

5.7 Joints and Sealing

Cables not having a moisture-resistant insulation are to be sealed against the admission of moisture by
methods such as taping in combination with insulating compound or sealing devices. Cables are to be
installed in such a manner that stresses on the cable are not transmitted to the conductors. Terminations and
joints in all conductors are to be so made as to retain the original electrical, flame retarding and, where
necessary, fire resisting properties of the cable. Terminal boxes are to be secured in place and the moisture-
resistant jacket is to extend through the cable clamp. Enclosures for outlets, switches and similar fittings
are to be flame and moisture-resistant and of adequate mechanical strength and rigidity to protect the contents
and to prevent distortion under all likely conditions of service. See also 4-6-3/5.17.1 and 4-6-3/5.29

5.9 Support, Fixing and Bending

5.9.1 Support and Fixing (1999)
5.9.1(a) Where cables are fixed by means of clips, saddles or straps, they are to have a surface
area so large and shaped such that the cables remain tight without their coverings being damaged.
Metal clips may be screwed directly to deck or bulkhead, except on watertight bulkheads.
5.9.1(b) The distances between supports are to be suitably chosen according to the type of cable
and the probability of vibration, and are not to exceed 400 mm (16 in.); for a horizontal cable run
where the cables are laid on cable supports in the form of tray plates, separate support brackets or
hanger ladders, the spacing between the fixing points may be up to 900 mm (36 in.), provided that
there are supports with maximum spacing, as specified above. This exemption does not apply to
cable runs along weather decks when the cable run is arranged so that the cables can be subjected
to forces by water washing over the deck.
Note: When designing a cable support system for single-core cables, consideration is also to be given to the
effects of electrodynamic forces developing on the occurrence of a short-circuit.
The above-given distances between cable supports are not necessarily adequate for these cables.
Further, other recognized standards for cable support and fixing will be considered.
5.9.1(c) The supports and the corresponding accessories are to be robust and are to be of
corrosion-resistant material or suitably treated before erection to resist corrosion.
5.9.1(d) Cable clips or straps made from an approved material other than metal (such as polyamide,
PVC) may be used.
5.9.1(e) When cables are fixed by means of clips or straps, referred to in Item 4-6-3/5.9.1(d) above,
and these cables are not laid on top of horizontal cable trays or cable supports, suitable metal cable
clips or saddles are to be added at regular distances not exceeding 2 m (6.5 ft) in order to prevent
the release of cables during a fire. This also applies to the fixing of non-metallic conduits or pipes.
Note: Item 4-6-3/5.9.1(e) does not necessarily apply in the case of cable runs with only one or a few cables
with small diameters for the connection of a lighting fitting, alarm transducer, etc.
5.9.1(f) (2004) Non-metallic clips, saddles or straps are to be flame retardant in accordance with
IEC Publication 60092-101.
5.9.2 Bending Radius
For bending radius requirements, see 4-6-3/Table 2.

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5.9.3 Plastic Cable Trays and Protective Casings (2004)

5.9.3(a) Installations (2008). Cable trays and protective casings made of plastic materials are to
be supplemented by metallic fixing and straps such that, in the event of a fire, they and the cables
affixed are prevented from falling and causing an injury to personnel and/or an obstruction to any
escape route. See 4-6-3/5.9.1(e). Cable trays and protective casings made of plastic materials are
to be flame retardant (see Appendix 4-8-4A1 of the Steel Vessel Rules). Where plastic cable trays
and protective casings are used on open deck, they are additionally to be protected against UV
light by such as anti-UV coating or equivalent.
Note: “Plastic” means both thermoplastic and thermosetting plastic materials with or without reinforcement,
such as PVC and fiber reinforced plastics (FRP). “Protective casing” means a closed cover in the form of
a pipe or other closed ducts of non-circular shape.
5.9.3(b) Safe Working Load (2008). The load on the cable trays and protective casings is to be
within the Safe Working Load (SWL). The support spacing is to be not greater than the manufacturer’s
recommendation nor in excess of the spacing at the SWL test (see Appendix 4-8-4A1 of the Steel
Vessel Rules). In general, the spacing is not to exceed 2 meters.
Note: The selection and spacing of cable tray and protective casing supports are to take into account:
• Dimensions of the cable trays and the protective casings;
• Mechanical and physical properties of their material;
• Mass of the cable trays/protective casings;
• Loads due to weight of cables, external forces, thrust forces and vibrations;
• Maximum accelerations to which the system may be subjected;
• Combination of loads.
5.9.3(c) Cable occupation ratio in protective casing. The sum of the total cross-sectional area of
all cables on the basis of their external diameter is not to exceed 40% of the internal cross-
sectional area of the protective casing. This does not apply to a single cable in a protective casing.
5.9.3(d) Hazardous areas (2008). Cable trays and protective casings passing through hazardous
areas are to be electrically conductive (see Appendix 4-8-4A1 of the Steel Vessel Rules).
5.9.3(e) Type Testing (2008). Cable trays and protective casings made of plastic materials are to
be type tested in accordance with Appendix 4-8-4A1 of the Steel Vessel Rules. Alternate test
procedures for impact resistance test, safe working load test, flame retardant test, smoke and
toxicity tests and/or resistivity test from an international or national standard may be considered
instead of the test specified in Appendix 4-8-4A1 of the Steel Vessel Rules. The type test reports
are to be submitted for review.

5.11 Cable Run in Bunches

5.11.1 Reduction of Current Rating
Where cables which may be expected to operate simultaneously are laid close together in a cable
bunch in such a way that there is an absence of free air circulation around them, the following
reduction factor is to be applied to the current rating obtained from 4-6-4/Table 10:

Number of Cables in One Bunch Reduction Factor

one to six 1.0
seven to twelve 0.85

Bunches of more than twelve cables will be subject to special consideration based on the type and
service of the various cables in the bunch.

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5.11.2 Clearance and Segregation

A clearance is to be maintained between any two cable bunches of at least the diameter of the
largest cable in either bunch. Otherwise, for the purpose of determining the number of cables in
the bunch, the total number of cables on both sides of the clearance will be used.
5.11.3 Cable of Lower Conductor Temperature
The current rating of each cable in a bunch is to be determined based on the lowest conductor
temperature rating of any cable in the bunch.

5.13 Deck and Bulkhead Penetrations

Where cables pass through watertight, firetight, or smoke-tight bulkheads or decks, the penetrations are to
be made through the use of approved stuffing tubes, transit devices or pourable materials which will
maintain the watertight, firetight or smoke-tight integrity of the bulkheads or decks. Additionally, each
such stuffing tube, transit device or pourable material is to be of a character so as not to damage the cable
physically or through chemical action or through heat build-up. When cables pass through non-watertight
bulkheads where the bearing surface is less than 6.4 mm (0.25 in.), the holes are to be fitted with bushings
having rounded edges and a bearing surface for the cable of at least 6.4 mm (0.25 in.) in length. Where
cables pass through deck beams or similar structural parts, all burrs are to be removed in way of the holes
and care is to be taken to eliminate sharp edges. Where cable conduit pipe or equivalent is carried through
decks or bulkheads, arrangements are to be made to maintain the integrity of the water or gas tightness of
the structure. Cables are not to pass through a collision bulkhead.

5.15 Mechanical Protection

5.15.1 Metallic Armor
Electric cables installed in locations liable to damage during normal operation of the vessel are to
be provided with braided, metallic armor and be otherwise suitably protected from mechanical
injury, as appropriate for the location. See also 4-6-3/11.1.3 for cables in hazardous areas.
5.15.2 Conduit Pipe or Structural Shapes
Where cables are installed in locations in way of cargo ports, hatches, tank tops, open decks subject
to seas, and where passing through decks, they are to be protected by substantial metal shields,
structural shapes, pipe or other equivalent means. All such coverings are to be of sufficient strength
to provide effective protection to the cables. When expansion bends are fitted, they are to be
accessible for maintenance. Where cables are installed in metal piping or in a metal conduit system,
such piping and systems are to be earthed and are to be mechanically and electrically continuous
across all joints.

5.17 Emergency and Essential Feeders

5.17.1 Location (2008)
As far as practicable, cables and wiring for emergency and essential services, including those listed
in 4-6-3/3.29, are not to pass through high fire risk areas (see 4-6-3/3.31).
These cables and wiring are also to be run in such a manner as to preclude their being rendered
unserviceable by heating of the bulkheads that may be caused by a fire in an adjacent space.
5.17.2 Services Necessary Under a Fire Condition (2008)
Where cables for services required to be operable under a fire condition (see 4-6-3/3.29) including
their power supplies pass through high fire risk areas (see 4-6-3/3.31) other than those which they
serve, they are to be so arranged that a fire in any of these areas does not affect the operation of
the service in any other area. This may be achieved by any of the following measures:
5.17.2(a) Fire resistant cables in accordance with 4-6-4/13.1.3 are installed and run continuous to
keep the fire integrity within the high fire risk area. See 4-6-3/Figure 2.

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FIGURE 2
Cables within High Fire Risk Areas (2008)

Other area High fire risk area Other area

EG ESB DB Electrical consumers

DB

Fire resistant cable Flame retardant cable Connection box

5.17.2(b) At least two loops/radial distributions run as widely apart as is practicable and so
arranged that in the event of damage by fire at least one of the loops/radial distributions remains
operational.
5.17.2(c) Cables used in systems that are self monitoring, fail safe or duplicated with cable runs
separated as widely as practicable, may be exempted.
5.17.3 Electrical Cables for the Emergency Fire Pump (1 July 2009)
The electrical cables to the emergency fire pump are not to pass through the machinery spaces
containing the main fire pumps and their sources of power and prime movers. They are to be of a
fire resistant type, in accordance with 4-6-3/5.17.2(a), where they pass through other high fire risk
areas.
5.17.4 Requirements by the Governmental Authority
Attention is directed to the requirements of the governmental authority of the country whose flag
the vessel flies for the installation of emergency circuits required in various types of vessels.

5.19 Mineral Insulated Cables

At all points where mineral-insulated metal-sheathed cable terminates, an approved seal is to be provided
immediately after stripping to prevent entrance of moisture into the mineral insulation. In addition, the
conductors extending beyond the sheath are to be insulated with an approved insulating material. When
mineral-insulated cable is connected to boxes or equipment, the fittings are to be approved for the conditions of
service. The connections are to be in accordance with the manufacturer’s installation recommendation.

5.21 Fiber Optic Cables

The installation of fiber optic cables is to be in accordance with the manufacturer’s recommendations to
prevent sharp bends where the fiber optic cables enter the equipment enclosure. Consideration is to be given
to the use of angled stuffing tubes. The cables are to be installed so as to avoid abrading, crushing, twisting,
kinking or pulling around sharp edges.

5.23 Battery Room

Where cables enter battery rooms, the holes are to be bushed, as required for watertight bulkheads in
4-6-3/5.13. All connections within battery rooms are to be resistant to the electrolyte. Cables are to be
sealed to resist the entrance of electrolyte by spray or creepage. The size of the connecting cable is to be
based on current-carrying capacities given in 4-6-4/Table 10 and the starting rate of charge or maximum
discharge rate, whichever is the greater, is to be taken into consideration in determining the cable size.

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5.25 Paneling and Dome Fixtures

Cables may be installed behind paneling, provided all connections are accessible and the location of
concealed connection boxes is indicated. Where a cable strip molding is used for cable installation on the
incombustible paneling, it is to be of incombustible material. Dome fixtures are to be installed so that they
are vented or they are to be fitted with fire-resistant material in such a manner as to protect the insulated
wiring leading to the lamps and any exposed woodwork from excessive temperature.

5.27 Sheathing and Structural Insulation

Cables may be installed behind sheathing, but they are not to be installed behind nor imbedded in structural
insulation. They are to pass through such insulation at right angles and are to be protected by a continuous
pipe with a stuffing tube at one end. For deck penetrations, this stuffing tube is to be at the upper end of the
pipe and for bulkhead penetrations, it is to be on the uninsulated side of the bulkhead. For refrigerated-
space insulation, the pipe is to be of phenolic or similar heat-insulating material joined to the bulkhead
stuffing tube, or a section of such material is to be inserted between the bulkhead stuffing tube and the
metallic pipe.

5.29 Splicing of Electrical Cables

5.29.1 Basis of Approval
Replacement insulation is to be fire-resistant and is to be equivalent in electrical and thermal
properties to the original insulation. The replacement jacket is to be at least equivalent to the original
impervious sheath and is to assure a watertight splice. Splices are to be made using an approved
splice kit which contains the following:
• Connector of correct size and number
• Replacement insulation
• Replacement jacket
• Instructions for use
In addition, prior to approval of a splicing kit, it will be required that completed splices be tested
for fire resistance, watertightness, dielectric strength, etc. to the satisfaction of the Surveyor. This
requirement may be modified for splice kits which have had such tests conducted and reported on
by an independent agency acceptable to ABS.
5.29.2 Installation
All splices are to be made after the cable is in place and are to be accessible for inspection. The
conductor splice is to be made using a pressure type butt connector by use of a one-cycle compression
tool. See 4-6-3/11.1.3 for splices in hazardous area.
5.29.3 Protection
Splices may be located in protected enclosures or in open wireways. Armored cables having splices
will not be required to have the armor replaced, provided that the remaining armor has been earthed
in compliance with 4-6-3/7.9 or provided that the armor is made electrically continuous. Splices
are to be so located such that stresses (as from the weight of the cable) are not carried by the splice.

5.31 Splicing of Fiber Optic Cables

Splicing of fiber optic cables is to be made by means of approved mechanical or fusion methods.

5.33 Cable Junction Box

Except for propulsion cables, junction boxes may be used in the installation of electric cables aboard the
vessel, provided the plans required by 4-6-3/1.3 for junction boxes are submitted and the following requirements
are complied with.

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5.33.1
The design and construction of the junction boxes are to comply with 4-6-4/11.7 as well as
4-6-3/5.33.2, below.
5.33.2
The junction boxes are to be suitable for the environment in which they are installed (i.e.,
explosion-proof in hazardous areas, watertight or weathertight on deck, etc.).
5.33.3 (1998)
Separate junction boxes are to be used for feeders and circuits of each of the following rated voltage
levels:
5.33.3(a) Rated voltage levels not exceeding those specified in 4-6-3/7.1i).
5.33.3(b) Rated voltage levels exceeding those in 4-6-3/5.33.3(a) up to and including 1 kV. A
physical barrier is to be used within the junction box to separate distribution systems of different
rated voltages, such as 480 V, 600 V and 750 V.
5.33.3(c) Rated voltage levels exceeding 1 kV. Separate junction boxes are to be used for each of
the rated voltage levels exceeding 1 kV.
Each junction box and the compartment in the junction box separated by a physical barrier are to
be appropriately identified as regards the rated voltage of the feeders and circuits that it contains.
A physical barrier may be used in lieu of two separate junction boxes for circuits having rated
voltage levels corresponding to those in either 4-6-3/5.33.3(a) or 4-6-3/5.33.3(b).
5.33.4
The junction boxes for emergency feeders and circuits are to be separate from those used for
normal ship service feeders and circuits.
5.33.5 (1998)
Cables are to be supported, as necessary, within junction boxes so as not to put stress (as from the
weight of the cable) on the cable contact mountings. The connections are to be provided with locking
type connections.
In addition to the above, the applicable requirements in 4-6-3/5 and 4-6-4/13 regarding cable
installation and application details are to be complied with.

7 Earthing

7.1 General
Exposed metal parts of electrical machines or equipment which are not intended to be live but which are
liable under fault conditions to become live are to be earthed unless the machines or equipment are:
i) (1998) supplied at a voltage not exceeding 50 volts DC or 50 volts AC r.m.s. between conductors;
auto-transformers are not to be used for the purpose of achieving this voltage; or
ii) Supplied at a voltage not exceeding 250 V AC r.m.s. by safety isolating transformers supplying
only one consuming device; or
iii) Constructed in accordance with the principle of double insulation.

7.3 Permanent Equipment

The metal frames or cases of all permanently installed generators, motors, controllers, instruments and similar
equipment are to be permanently earthed through a metallic contact with the vessel’s structure. Alternatively,
they are to be connected to the hull by a separate conductor, in accordance with 4-6-3/7.5. Where outlets,
switches and similar fittings are of non-metallic construction, all exposed metal parts are to be earthed.

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7.5 Connections
7.5.1 General
All earthing conductors are to be of copper or other corrosion-resistant material and are to be protected
against damage. The nominal cross-sectional area of every copper earthing conductor is to be not
less than that required by 4-6-3/Table 3.
7.5.2 Earthed Distribution System
Earthing conductors in an earthed distribution system are to comply with 4-6-3/7.5.1, except that
the earthing conductor in line C4 of 4-6-3/Table 3 is to be A/2.
7.5.3 Connection to Hull Structure
All connections of an earth-continuity conductor or earthing lead to the vessel’s structure are to be
made in an accessible position and be secured by a screw of brass or other corrosion-resistant material
having a cross-sectional area equivalent to the earth-continuity conductor or earthing lead, but not
less than 4 mm (0.16 in.) in diameter. The earth connection screw is to be used for this purpose only.
See 4-4-1/9.21 for control of static electricity.

7.7 Portable Cords (1998)

Receptacle outlets operating at 50 volts DC or 50 volts AC r.m.s. or more are to have an earthing pole.

7.9 Cable Metallic Covering

All metal sheaths, armor of cable and mineral-insulated, metal-sheathed cable are to be electrically continuous
and are to be earthed to the metal hull at each end of the run, except that final sub-circuits may be earthed
at the supply end only. All metallic coverings of power and lighting cables passing through hazardous areas
or connected to equipment in such an area are to be earthed at least at each end. See also 4-7-2/15.9.3.

7.11 Lightning Earth Conductors

Each wooden mast or topmast is to be fitted with lightning earth conductors. They need not be fitted to
steel masts.

9 Installation in Cargo Hold for Dry Bulk Cargoes

9.1 Equipment
The installation of electrical equipment in cargo holds for dry bulk cargoes is to be limited to only that
which is absolutely necessary. Where electrical equipment must be installed in such spaces, it is to be
protected from mechanical damage. All electrical equipment in cargo holds or spaces through which cargo
passes is to have an IP55 enclosure, as defined in 4-6-1/15.

9.3 Self-Unloading Controls and Alarms

9.3.1 General
Where vessels are equipped with self-unloading systems, controls are to be provided for the safe
operation of the self-unloading system. These controls are to be clearly marked to show their functions.
Energizing the power unit at a location other than the cargo control station is not to set the gear in
motion.
9.3.2 Monitors
As appropriate, monitoring is to indicate the system operational status (operating or not operating),
availability of power, overload alarm, air pressure, hydraulic pressure, electrical power or current,
motor running and motor overload and brake mechanism engagement.
9.3.3 Emergency Shutdowns
Remote emergency shutdowns of power units for self-unloading equipment are to be provided
outside of the power unit space so that they may be stopped in the event of fire or other emergency.
Where remote controls are provided for cargo gear operation, means for the local emergency
shutdowns are to be provided.

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11 Equipment and Installation in Hazardous Areas

11.1 General Considerations

11.1.1 General (2008)
Electrical equipment and wiring are not to be installed in hazardous areas unless essential for
operational purposes.
11.1.1(a) Electrical Equipment Types. Only electrical equipment of the following types, complying
with IEC Publication 60079 or other recognized standards, is to be considered for installation in
hazardous areas.
• Intrinsically safe type (Ex i)
• Flameproof (explosion-proof) type (Ex d)
• Increased safety type (Ex e)
• Pressurized or purged type (Ex p)
Consideration is to be given to the flammability group and the temperature class of the equipment
for suitability for the intended hazardous area, see IEC Publication 60079-20.
11.1.1(b) Fans. Fans used for the ventilation of the hazardous areas are to be of non-sparking
construction in accordance with 4-6-3/11.7.
11.1.2 Lighting Circuits (2002)
All switches and protective devices for lighting fixtures in hazardous areas are to interrupt all
poles or phases and are to be located in a non-hazardous area. However, a switch may be located
in a hazardous area if the switch is of a certified safe type for the hazardous location in which it is
to be installed. On solidly grounded distribution systems, the switches need not open the grounded
conductor. The switches and protective devices for lighting fixtures are to be suitably labeled for
identification purposes.
11.1.3 Cables Installation (2006)
Cables in hazardous areas are to be armored or mineral-insulated metal-sheathed, except for cables
of intrinsically safe circuits subject to the requirements of 4-6-3/5.15. Where cables pass through
hazardous area boundaries, they are to be run through gastight fittings. No splices are allowed in
hazardous areas, except in intrinsically-safe circuits.
11.1.4 Permanent Warning Plates
Permanent warning plates are to be installed in the vicinity of hazardous areas in which electrical
equipment is installed, such as the pump room, to advise personnel carrying out maintenance,
repair or surveys of the availability of the booklet/list of equipment in hazardous areas referenced
in 4-6-3/1.5, if required for their use.

11.3 Certified-safe Type and Pressurized Equipment and Systems

11.3.1 Installation Approval
Electrical equipment in hazardous areas is to be of a type suitable for such locations. Where
permitted by the Rules, electrical equipment of a certified safe type, such as explosion-proof type
and intrinsically-safe electrical instruments, circuitry and devices, will be approved for installation,
provided such equipment has been type-tested and certified by a competent independent testing
laboratory as explosion-proof or intrinsically-safe and provided that there is no departure in the
production equipment from the design so tested and approved.

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11.3.2 Intrinsically-safe System (2005)

11.3.2(a) Installation of Cables and Wiring. Installations with intrinsically safe circuits are to be
erected in such a way that their intrinsic safety is not adversely affected by external electric or
magnetic fields under normal operating condition and any fault conditions, such as a single-phase
short circuit or earth fault in non-intrinsically safe circuits, etc.
11.3.2(b) Separation and Mechanical Protection. The installation of the cables is to be arranged
as follows:
i) Cables in both hazardous and non-hazardous areas are to meet one of the following
requirements:
• Intrinsically safe circuit cables are to be installed a minimum of 50 mm (2 in.) from
all non-intrinsically safe circuit cables, or
• Intrinsically safe circuit cables are to be so placed as to protect against the risk of
mechanical damage by use of a mechanical barrier, or
• Intrinsically safe or non-intrinsically safe circuit cables are to be armored, metal
sheathed or screened.
ii) Conductors of intrinsically safe circuits and non-intrinsically safe circuits are not to be
carried in the same cable.
iii) Cables of intrinsically safe circuits and non-intrinsically safe circuits are not to be in the
same bundle, duct or conduit pipe.
iv) Each unused core in a multi-core cable is to be adequately insulated from earth and from
each other at both ends by the use of suitable terminations.
11.3.2(c) Sub-compartment. When intrinsically safe components are located by necessity within
enclosures that contain non-intrinsically safe systems, such as control consoles and motor starters,
such components are to be effectively isolated in a sub-compartment by earthed metallic or
nonmetallic insulating barriers having a cover or panel secured by bolts, locks, Allen-screws, or
other approved methods. The intrinsic safety in the sub-compartment is not to be adversely affected
by external electric or magnetic fields under normal operating condition and any fault conditions
in non-intrinsically safe circuits.
11.3.2(d) Termination Arrangements. Where it is impracticable to arrange the terminals of
intrinsically safe circuit in the sub-compartment, they are to be separated from those for non-
intrinsically safe circuits by either of the following methods. Other National or International
recognized Standards will also be accepted.
i) When separation is accomplished by distance, then the clearance between terminals is to
be at least 50 mm, or
ii) When separation is accomplished by use of an insulating partition or earthed metal partition,
the partitions are to extend to within 1.5 mm of the walls of the enclosure, or alternatively
provide a minimum measurement of 50 mm between the terminals when taken in any
direction around the partition.
11.3.2(e) Identification Plate. The terminals and sub-compartment for intrinsically safe circuit
and components are to have a nameplate indicating that the equipment within is intrinsically safe
and that unauthorized modification or repairs are prohibited.
11.3.2(f) Replacement. Unless specifically approved, replacement equipment for intrinsically-
safe circuits is to be identical to the original equipment.

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11.3.3 Pressurized Equipment

Pressurized equipment is to consist of separately ventilated enclosures supplied with positive-
pressure ventilation from a closed-loop system or from a source outside the hazardous areas, and
provision is to be made such that the equipment cannot be energized until the enclosure has been
purged with a minimum of ten air changes and required pressure is obtained. Ventilating pipes are
to have a minimum wall thickness of 3 mm (0.12 in. or 11 gage). In the case of loss of pressurization,
power is to be automatically removed from the equipment, unless this would result in a condition
more hazardous than that created by failure to de-energize the equipment. In this case, in lieu of
removal of power, an audible and visual alarm is to be provided at a normally manned control station.
Pressurized equipment in compliance with IEC Pub. 60079-2, NFPA 496 or other recognized
standard will also be acceptable.

11.5 Paint Stores

11.5.1 General
Electrical equipment in paint stores and in ventilation ducts serving such spaces as permitted in
4-6-3/11.1.1 is to comply with the requirements for group IIB class T3 in IEC Publication 60079.
The following type of equipment will be acceptable for such spaces.
i) Intrinsically-safe defined by 4-6-1/3.11
ii) Explosion-proof defined by 4-6-1/3.5
iii) Pressurized defined by 4-6-1/3.23
iv) Increased safety defined by 4-6-1/3.13
v) Other equipment with special protection recognized as safe for use in explosive gas
atmospheres by a national or other appropriate authority.
11.5.2 Open Area Near Ventilation Openings
In the areas on open deck within 1 m (3.3 ft) of the ventilation inlet or within 1 m (3.3 ft) (if natural)
or 3 m (10 ft) (if mechanical) of the exhaust outlet, electrical equipment and cables, where permitted
by 4-6-3/11.1.1, are to be in accordance with 4-6-3/11.1.2, 4-6-3/11.1.3 and 4-6-3/11.3.1.
11.5.3 Enclosed Access Spaces
The enclosed spaces giving access to the paint store may be considered as nonhazardous, provided
that:
i) The door to the paint store is gastight with self-closing devices without holding back
arrangements,
ii) The paint store is provided with an acceptable, independent, natural ventilation system
ventilated from a safe area, and
iii) Warning notices are fitted adjacent to the paint store entrance stating that the store contains
flammable liquids.

11.7 Non-sparking Fans

11.7.1 Design Criteria
11.7.1(a) Air Gap. The air gap between the impeller and the casing is to be not less than 10% of
the shaft diameter in way of the impeller bearing, but not less than 2 mm (0.08 in.). It need not be
more than 13 mm (0.5 in.).
11.7.1(b) Protection Screen. Protection screens of not more than 13 mm (0.5 in.) square mesh
are to be fitted in the inlet and outlet of ventilation openings on the open deck to prevent the entrance
of an object into the fan casing.

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11.7.2 Materials
11.7.2(a) Impeller and its Housing. Except as indicated in 4-6-3/11.7.2(c) below, the impeller and
the housing in way of the impeller are to be made of alloys which are recognized as being spark
proof by appropriate test.
11.7.2(b) Electrostatic Charges. Electrostatic charges both in the rotating body and the casing
are to be prevented by the use of antistatic materials. Furthermore, the installation on board of the
ventilation units is to be such as to ensure the safe bonding to the hull of the units themselves.
11.7.2(c) Acceptable Combination of Materials. Tests referred to in 4-6-3/11.7.2(a) above are
not required for fans having the following combinations:
i) Impellers and/or housings of nonmetallic material, due regard being paid to the elimination
of static electricity;
ii) Impellers and housings of non-ferrous materials;
iii) Impellers of aluminum alloys or magnesium alloys and a ferrous (including austenitic stainless
steel) housing on which a ring of suitable thickness of non-ferrous materials is fitted in
way of the impeller;
iv) Any combination of ferrous (including austenitic stainless steel) impellers and housings with
not less than 13 mm (0.5 in.) Tip design clearance.
11.7.2(d) Unacceptable Combination of Materials. The following impellers and housings are
considered as sparking-producing and are not permitted:
i) Impellers of an aluminum alloy or magnesium alloy and a ferrous housing, regardless of
tip clearance;
ii) Housing made of an aluminum alloy or a magnesium alloy and a ferrous impeller, regardless
of tip clearance;
iii) Any combination of ferrous impeller and housing with less than 13 mm (0.5 in.) design
tip clearance.
11.7.3 Type Test (2007)
Type tests on the finished product are to be carried out using an acceptable national or international
standard. Such type test reports are to be made available when requested by the Surveyor.

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TABLE 1
Minimum Degree of Protection [See 4-6-3/3.1.1]
Switchboards, distribution boards, motor control
centers & controllers (See 4-6-3/3.9 to 4-6-3/3.13)
Generators (See 4-6-3/3.3)
Example Condition Motors (See 4-6-3/3.5)
of of Transformers, Converters
Location Location Lighting fixtures
(See 4-6-3/3.17)
Heating appliances
(See 4-6-3/3.19)
Accessories (3)

Dry accommodation space Danger of touching live IP20 - IP20 IP20 IP20 IP20 IP20
(4) parts only
Dry control rooms (1999) IP20 - IP20 IP20 IP20 IP20 IP20
Control rooms (1999) Danger of dripping liquid IP22 - IP22 IP22 IP22 IP22 IP22
Machinery spaces above floor plates (5) and/or moderate mechanical IP22 IP22 IP22 IP22 IP22 IP22 IP44
damage
Steering gear rooms IP22 IP22 IP22 IP22 IP22 IP22 IP44
Refrigerating machinery rooms IP22 - IP22 IP22 IP22 IP22 IP44
Emergency machinery rooms IP22 IP22 IP22 IP22 IP22 IP22 IP44
General store rooms IP22 - IP22 IP22 IP22 IP22 IP22
Pantries IP22 - IP22 IP22 IP22 IP22 IP44
Provision rooms IP22 - IP22 IP22 IP22 IP22 IP22
Bathrooms and Showers Increased danger of liquid - - - - IP34 IP44 IP55
and/or mechanical damage
Machinery spaces below floor plates - - IP44 - IP34 IP44 IP55 (2)
Closed fuel oil or lubricating oil IP44 - IP44 - IP34 IP44 IP55 (2)
separator rooms
Ballast pump rooms Increased danger of liquid IP44 - IP44 IP44 IP34 IP44 IP55
and mechanical damage
Refrigerated rooms - - IP44 - IP34 IP44 IP55
Galleys and Laundries IP44 - IP44 IP44 IP34 IP44 IP44
Shaft or pipe tunnels in double bottom Danger of liquid spray IP55 - IP55 IP55 IP55 IP55 IP56
presence of cargo dust,
Holds for general cargo - - - - IP55 - IP55
serious mechanical damage,
and/or aggressive fumes
Open decks Exposure to heavy seas IP56 - IP56 - IP55 IP56 IP56
Bilge wells Exposure to submersion - - - - IPX8 - IPX8
Notes
1 Empty spaces shown with “-“ indicate installation of electrical equipment is not recommended.
2 Socket outlets are not to be installed in machinery spaces below the floor plates, enclosed fuel and lubricating oil
separator rooms or spaces requiring certified safe equipment.
3 “Accessories” include switches, detectors, junction boxes, etc. Accessories which are acceptable for use in hazardous
areas are limited by the condition of the areas. Specific requirements are given in the Rules. See 4-6-3/3.23.
4 (1999) For the purpose of this Table, the wheelhouse may be categorized as a “dry control room” and consequently,
the installation of IP20 equipment would suffice therein, provided that: (a) the equipment is located as to preclude
being exposed to steam or dripping/spraying liquids emanating from pipe flanges, valves, ventilation ducts and
outlets, etc., installed in its vicinity, and (b) the equipment is placed to preclude the possibility of being exposed to
sea or rain.
5 (2006) See 4-6-3/3.1.1(b) where the equipment is located within areas protected by local fixed pressure water-
spraying or water-mist fire extinguishing system and its adjacent areas.

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TABLE 2
Minimum Bending Radii of Cables [See 4-6-3/5.9.2] (1999)
Cable Construction Overall Diameter, Minimum Internal
Insulation Outer Covering D Bending Radius
Thermoplastic or Unarmored or unbraided D ≤ 25 mm (1 in.) 4D
thermosetting with
D > 25 mm 6D
circular copper
conductor Metal braid screened or armored Any 6D
Metal wire or metal-tape armored or Any 6D
metal-sheathed
Composite polyester/metal laminate Any 8D
tape screened units or collective tape
screening
Thermoplastic or Any Any 8D
thermosetting with
shaped copper
conductor
Mineral Hard metal-sheathed Any 6D

TABLE 3
Size of Earth-continuity Conductors and Earthing Connections
[See 4-6-3/7.5] (2003)
Cross-sectional Area, A, of
Minimum Cross-sectional Area of
Type of Earthing Connection Associated Current
Copper Earthing Connection
Carrying Conductor
2
A1 A ≤ 16 mm A
Earth-continuity conductor in 2 2
A2 16 mm < A ≤ 32 mm 16 mm2
flexible cable or flexible cord 2
A3 A > 32 mm A/
2
For cables having an insulated earth-continuity conductor
B1a A ≤ 1.5 mm2 1.5 mm2
2 2
B1b 1.5 mm < A ≤ 16 mm A
Earth-continuity conductor B1c 16 mm2 < A ≤ 32 mm2 16 mm2
incorporated in fixed cable B1d A > 32 mm2 A/
2
For cables with bare earth wire in direct contact with the lead sheath
B2a A ≤ 2.5 mm2 1 mm2
2 2
B2b 2.5 mm < A ≤ 6 mm 1.5 mm2
C1a Stranded earthing connection:
1.5 mm2 for A ≤ 1.5 mm2
2
A ≤ 3 mm A for A > 1.5 mm2
C1b Unstranded earthing connection:
Separate fixed earthing conductor
3 mm2
2 2
C2 3 mm < A ≤ 6 mm 3 mm2
2 2
C3 6 mm < A ≤ 125 mm A/
2
2 2
C4 A > 125 mm 64 mm (see Note 1)
Notes:
1 (2003) For earthed distribution systems, the size of earthing conductor is not to be less than A/2.
2 Conversion Table for mm2 to circular mils:
mm2 circ. mils mm2 circ. mils mm2 circ. mils mm2 circ. mils
1 1,973 2.5 4,933 6 11,841 70 138,147
1.5 2,960 4 7,894 16 31,576 120 236,823

234 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 4: Machinery and Equipment

4
CHAPTER 6 Electrical Installations

SECTION 4 Machinery and Equipment

1 Plans and Data to Be Submitted (2010)

1.1 Rotating Machines of 100 kW and Over

For rotating machines of 100 kW and over intended for essential services (primary and secondary) or for
services indicated in 4-6-4/Table 11, drawings showing the following particulars are to be submitted: assembly,
seating arrangements, terminal arrangements, shafts, coupling, coupling bolts, stator and rotor details together
with data for complete rating, class of insulation, designed ambient temperature, temperature rise, degree
of protection for enclosures, weights and speeds for rotating parts. Plans to be submitted for generator prime
movers are given in 4-2-3/1.5, 4-2-4/1.5 and 4-2-1/1.9 of the Steel Vessel Rules.

1.3 Switchboards, Distribution Boards, Controllers, etc.

For switchboards, distribution boards, battery charger units, uninterruptible power system (UPS) units, motor
control centers, and motor controllers intended for essential services (primary and secondary) or for services
indicated in 4-6-4/Table 11, drawings showing arrangements and details, front view, and installation
arrangements are to be submitted for review together with data for protective device rating and setting,
type of internal wiring, and size and rated current carrying capacity (together with short-circuit current
data) of bus bars and internal wiring for power circuit. In addition, a schematic or logic diagram with a
written description giving the sequence of events and system operating procedures for electrical power
supply management on switchboards and sequential or automatic change-over of the motors are also to be
submitted for review.

3 Rotating Machines

3.1 General
3.1.1 Applications (2010)
All rotating electrical machines of 100 kW and over intended for essential services (see 4-6-1/3.3)
or for services indicated in 4-6-4/Table 11 are to be designed, constructed and tested in accordance
with the requirements of 4-6-4/3.
All other rotating electrical machines are to be designed, constructed, and tested in accordance
with established industrial practices and manufacturer’s specifications. Manufacturer’s tests for
rotating electric machines less than 100 kW for essential services or for services indicated in
4-6-4/Table 11 are to include at least the tests described in 4-6-4/3.3.1(b), regardless of the standard
of construction The test certificates are to be made available when requested by the Surveyor.
Acceptance of machines will be based on satisfactory performance test after installation.
3.1.2 Certification on Basis of an Approved Quality Assurance Program
See 4-1-1/3.

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3.1.3 References
3.1.3(a) Inclination. For the requirements covering inclination for design condition, see 4-1-1/17.
3.1.3(b) Insulation Material. For the requirements covering insulation material, see 4-6-1/13.
3.1.3(c) Capacity of Generators. For requirements covering main generator capacity, see 4-6-
2/3.1.2 and 4-6-2/3.5. For requirements covering emergency generator capacity, see 4-6-2/5.3.1.
3.1.3(d) Power Supply by Generators. For requirements covering power supply by main or
emergency generator, see 4-6-2/3.1.2 and 4-6-2/5.5.2, respectively.
3.1.3(e) Protection for Generator Circuits. For requirements covering protection for generator,
see 4-6-2/9.3, 4-6-2/9.5 and 4-6-2/9.7.
3.1.3(f) Protection for Motor Circuits. For requirements covering protection for motor branch
circuit, see 4-6-2/9.13.
3.1.3(g) Installation. For requirements covering installation, see 4-6-3/3.3 for generators and 4-
6-3/3.5 for motors.
3.1.3(h) Protection Enclosures and its Selection. For requirements covering degree of the protection
and the selection of equipment, see 4-6-1/15 and 4-6-3/3.1, respectively.

3.3 Testing and Inspection

3.3.1 Applications (2010)
3.3.1(a) Machines of 100 kW and Over. All rotating machines of 100 kW and over intended for
essential services (see 4-6-1/3.3) or for services indicated in 4-6-4/Table 11 are to be tested in
accordance with 4-6-4/Table 1 in the presence of and inspected by the Surveyor, preferably at the
plant of the manufacturer.
3.3.1(b) Machines Below 100 kW. All rotating machines of less than 100 kW intended for essential
services or for services indicated in 4-6-4/Table 11 are to be tested in accordance with 4-6-4/Table
1 (item 2 through item 10 and item 12). The tests may be carried out by the manufacturer whose
certificate of tests will be acceptable and is to be submitted upon request from ABS.
3.3.1(c) Other Machines. For machines not intended for essential services or for services indicated
in 4-6-4/Table 11, the tests may be carried out by the manufacturer whose certificate of tests will
be acceptable and is to be submitted upon request from ABS.
3.3.2 Special Testing Arrangements
In cases where all of the required tests are not carried out at the plant of the manufacturer, the
Surveyor is to be notified and arrangements are to be made so that the remaining tests will be
witnessed.

3.5 Insulation Resistance Measurement

The resistance is to be measured before the commencement of the testing and after completion of the
testing for all circuits. Circuits or groups of circuits of different voltages above earth are to be tested
separately. This test is to be made with at least 500 volts DC and the insulation resistance in megohms of
the circuits while at their operating temperatures is to be normally at least equal to:
Rated Voltage of the Machine
(Rating in kVA/100) + 1000
The minimum insulation resistance of the fields of machines separately excited with voltage less than the
rated voltage of the machine is to be on the order of one-half to one megohm.

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Section 4 Machinery and Equipment 4-6-4

3.7 Overload and Overcurrent Capability

3.7.1 AC Generators (2003)
AC generators are to be capable of withstanding a current equal to 1.5 times the rated current for
not less than 30 seconds. The test may be performed in conjunction with the short circuit testing,
provided the electrical input energy to the machine is not less than that required for the above
overload capability.
3.7.2 AC Motors
3.7.2(a) Overcurrent Capacity (2003). Three phase motors, except for commutator motors, having
rated outputs not exceeding 315 kW and rated voltages not exceeding 1 kV are to be capable of
withstanding a current equal to 1.5 times the rated current for not less than two minutes. For three-
phase and single phase motors having rated outputs above 315 kW, the overcurrent capacity is to
be in accordance with the manufacturer’s specification. The test may be performed at a reduced speed.
3.7.2(b) Overload Capacity. Three-phase induction motors are to be capable of withstanding for
15 seconds, without stalling or abrupt change in speed, an excess torque of 60% of their rated
torque, the voltage and frequency being maintained at their rated values.
3.7.2(c) Overload Capacity for Synchronous Motors. Three phase synchronous motors are to be
capable of withstanding an excess torque, as specified below, for 15 seconds without falling out of
synchronism, the excitation being maintained at the value corresponding to the rated load.

Synchronous (wound rotor) 35% excess torque

induction motors:
Synchronous (cylindrical rotor) 35% excess torque
motors:
Synchronous (salient pole) 50% excess torque
motors:

When automatic excitation is used, the limit of torque values is to be the same as with the
excitation equipment operating under normal conditions.

3.9 Dielectric Strength of Insulation

3.9.1 Application
The dielectric test voltage is to be successively applied between each electric circuit and all other
electric circuits and metal parts earthed, and for direct-current (DC) rotating machines between
brush rings of opposite polarity. Interconnected polyphase windings are to be considered as one
circuit. All windings except that under test are to be connected to earth.
3.9.2 Standard Voltage Test (2003)
The insulation of all rotating machines is to be tested with the parts completely assembled and not
with the individual parts. The dielectric strength of the insulation is to be tested by the continuous
application for 60 seconds of an alternating voltage having a frequency of 25 to 60 Hz and voltage
in 4-6-4/Table 2. The requirements in 4-6-4/Table 2 apply to those machines other than high
voltage systems covered by 4-6-5/1.11.1(f).
3.9.3 Direct Current Test
A standard voltage test using a direct current source equal to 1.7 times the required alternating-
current voltage will be acceptable.

3.11 Temperature Ratings

3.11.1 Temperature Rises
3.11.1(a) Continuous Rating Machines. After the machine has been run continuously under a
rated load until steady temperature condition has been reached, the temperature rises are not to
exceed those given in 4-6-4/Table 3.

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3.11.1(b) Short-time Rating Machines. After the machine has been run at a rated load during the
rated time followed by a rest and a de-energized period of sufficient duration to re-establish the
machine temperatures within 2°C (3.6°F) of the coolant, the temperature rises are not to exceed
those given in 4-6-4/Table 3. At the beginning of the temperature measurement, the temperature of
the machine is to be within 5°C (8°F) of the temperature of the coolant.
3.11.1(c) Periodic Duty Rating Machines. The machine has been run at a rated load for the
designed load cycle to be applied and continued until obtaining the practically identical temperature
cycle. At the middle of the period causing the greatest heating in the last cycle of the operation,
the temperature rises are not to exceed those given in 4-6-4/Table 3.
3.11.1(d) Non-periodic Duty Rating Machines. After the machine has been run continuously or
intermittently under the designed variations of the load and speed within the permissible operating
range until reaching the steady temperature condition, the temperature rises are not to exceed
those given in 4-6-4/Table 3.
3.11.1(e) Insulation Material Above 180°C (356°F). Temperature rises for insulation materials
above 180°C (356°F) will be considered in accordance with 4-6-1/13.11.
3.11.2 Ambient Temperature (2007)
These final temperatures are based on an ambient temperature of 50°C (122°F), for machines
located within boiler and engine rooms in accordance with 4-6-1/17. Where provision is made for
ensuring the ambient temperature of the space is being maintained at 40°C (104°F) or less, as by
air cooling or by locating the machine outside of the boiler and engine rooms, the temperature
rises of the windings may be 5°C (9°F) higher. The ambient temperature is to be taken in at least
two places within 1.83 m (6 ft) of the machine under test and by thermometers having their bulbs
immersed in oil contained in an open cup.

3.13 Construction and Assemblies

3.13.1 Enclosure, Frame and Pedestals
Magnet frames and pedestals may be separate but are to be secured to a common foundation.
3.13.2 Shafts and Couplings (2006)
3.13.1(a) Rotors of non-integrated auxiliary machinery. The design of the following specified
rotating shafts and components, when not integral with the propulsion shafting, are to comply with
the following:
• Rotor shaft: 4-2-4/5.3.1* and 4-2-4/5.3.2*
• Hollow shaft: 4-3-1/7.3
• Key: 4-3-1/9 and 4-2-4/5.3.2*
• Coupling flanges and bolts: 4-3-1/19
* Note: Rules for Building and Classing Steel Vessels
3.13.2(b) Rotors of integrated auxiliary machinery. Shaft motors and shaft generators, which are
an integral part of the line shafting, shall be evaluated for maximum combined load (steady and
dynamic torque and bending) acting within operating range of installation. Accordingly, the shaft
diameter design criteria per 4-2-4/5.3.1 and 4-2-4/5.3.2 of the Steel Vessel Rules is to be evaluated
for maximum torsional moment acting within the operating speeds, instead of torsional moment T
at rated speed.
3.13.3 Circulating Currents
Means are to be provided to prevent circulating currents from passing between the journals and
the bearings, where the design and arrangement of the machine is such that damaging current may
be expected. Where such protection is required, a warning plate is to be provided in a visible place
cautioning against the removal of such protection.

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Section 4 Machinery and Equipment 4-6-4

3.13.4 Rotating Exciters

Rotating exciters are to conform to all applicable requirements for generators.
3.13.5 Insulation of Windings
Armature and field coils are to be treated to resist oil and water.
3.13.6 Protection Against Cooling Water
Where water cooling is used, the cooler is to be so arranged as to avoid entry of water into the
machine, whether through leakage or from condensation in the heat exchanger.
3.13.7 Moisture-condensation Prevention
When the weight of the rotating machine, excluding the shaft, is over 455 kg (1000 lb), it is to be
provided with means to prevent moisture condensation in the machine when idle. Where steam-
heating coils are installed for this purpose, there are to be no pipe joints inside of the casings. See
item 7 in 4-6-4/Table 7 for space heater pilot lamp for alternating-current generators.
3.13.8 Terminal Arrangements
Terminals are to be provided at an accessible position and protected against mechanical damage
and accidental contact for earthing, short-circuit or touching. Terminal leads are to be secured to
the frame and the designation of each terminal lead are to be clearly marked. The ends of terminal
leads are to be fitted with connectors. Cable glands or similar are to be provided where cable
penetrations may compromise the protection property of terminal enclosures.
3.13.9 Nameplates
Nameplates of corrosion-resistant material are to be provided in an accessible position of the
machine and are to indicate at least the information as listed in 4-6-4/Table 4a.

3.15 Lubrication
Rotating machines are to have continuous lubrication at all running speeds and all normal working bearing
temperatures, with the vessel’s inclinations specified in 4-1-1/17. Unless otherwise approved, where forced
lubrication is employed, the machines are to be provided with means to shut down their prime movers
automatically upon failure of the lubricating system. Each self-lubricating sleeve bearing is to be fitted
with an inspection lid and means for visual indication of oil level or an oil gauge.

3.17 Turbines for Generators

Gas-turbine prime movers driving generators are to meet the applicable requirements in Section 4-2-3 of
the Steel Vessel Rules and, in addition, are to comply with the following requirements.
3.17.1 Operating Governor (2004)
An effective operating governor is to be fitted on prime movers driving main or emergency electric
generators and is to be capable of automatically maintaining the speed within the following limits.
Special consideration will be given when an installation requires different characteristics.
3.17.1(a) Transient Frequency Variations. The transient frequency variations in the electrical
network, when running at the indicated loads below, are to be within ±10% of the rated frequency
when:
i) Running at full load (equal to rated output) of the generator and the maximum electrical
step load is suddenly thrown off,
In the case when a step load equivalent to the rated output of a generator is thrown off, a
transient frequency variation in excess of 10% of the rated frequency may be acceptable,
provided the overspeed protective device, fitted in addition to the governor, as required by
4-6-4/3.17.2, is not activated.
ii) Running at no load and 50% of the full load of the generator is suddenly thrown on followed
by the remaining 50% load after an interval sufficient to restore the frequency to steady state.
In all instances, the frequency is to return to within ±1% of the final steady state condition
in no more than five seconds.

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3.17.1(b) Frequency Variations in Steady State. The permanent frequency variation is to be within
±5% of the rated frequency at any load between no load and full load.
3.17.1(c) Emergency Generator Prime Movers. For gas turbines driving emergency generators,
the requirements of 4-6-4/3.17.1(a) and 4-6-4/3.17.1(b) are to be met. However, for the purpose of
4-6-4/3.17.1(a)ii), where the sum of all loads that can be automatically connected is larger than
50% of the full load of the emergency generator, the sum of these loads is to be used as the first
applied load.
3.17.2 Overspeed Governor
In addition to the normal operating governor, an overspeed governor is to be fitted which will trip
the turbine throttle when the rated speed is exceeded by more than 15%. Provision is to be made
for hand tripping. See 4-6-4/3.15 for pressure-lubricated machines.
3.17.3 Power Output of Gas Turbines
To satisfy the requirements of 4-6-2/3.1, the required power output of gas turbine prime movers
for ship’s service generator sets is to be based on the maximum expected inlet air temperature.

3.19 Diesel Engines for Generators

Diesel-engine prime movers are to meet the applicable requirements in Part 4, Chapter 2 and, in addition,
are to comply with the following requirements.
3.19.1 Operating Governor (2004)
An effective operating governor is to be fitted on prime movers driving main or emergency electric
generators and is to be capable of automatically maintaining the speed within the following limits.
Special consideration will be given when an installation requires different characteristics.
3.19.1(a) Transient Frequency Variations (2007). The transient frequency variations in the electrical
network, when running at the indicated loads below, are to be within ±10% of the rated frequency with
a recovery time within ±1% of the final steady state condition in not more than 5 seconds when:
i) Running at full load (equal to rated output) of the generator and the maximum electrical
step load is suddenly thrown off,
In the case when a step load equivalent to the rated output of a generator is thrown off, a
transient frequency variation in excess of 10% of the rated frequency may be acceptable,
provided the overspeed protective device, fitted in addition to the governor, as required by
4-6-4/3.19.2, is not activated.
ii) Running at no load and 50% of the full load of the generator is suddenly thrown on
followed by the remaining 50% load after an interval sufficient to restore the frequency to
steady state.
3.19.1(b) Power Management System. Where the electrical power system is fitted with a power
management system and sequential starting arrangements, the application of loads in multiple
steps of less than 50% of rated load in 4-6-4/3.19.1(a)ii) above may be permitted, provided it is in
accordance with 4-6-4/Figure 1. The details of the power management system and sequential
starting arrangements are to be submitted and its satisfactory operation is to be demonstrated to
the Surveyor.

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Part 4 Vessel Systems and Machinery
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Section 4 Machinery and Equipment 4-6-4

FIGURE 1
Limiting Curves for Loading 4-stroke Diesel Engines
Step by Step from No-load to Rated Power as Function
of the Brake Mean Effective Pressure (1998)

3.19.1(c) Frequency Variations in Steady State. The permanent frequency variation is to be within
±5% of the rated frequency at all loads between no load and full load.
3.19.1(d) Emergency Generator Prime Movers (2007). For prime movers driving emergency
generators, the requirements of 4-6-4/3.19.1(a)i) and 4-6-4/3.19.1(c) above are to be met even
when:
i) Their total consumer load is applied suddenly, or
ii) Their total consumer load is applied in steps, subject to:
• The total load is supplied within 45 seconds since power failure on the main switchboard
• The maximum step load is declared and demonstrated
• The power distribution system is designed such that the declared maximum step loading
is not exceeded
• The compliance of time delays and loading sequence with the above is to be
demonstrated at ship’s trials.
3.19.2 Overspeed Governor
In addition to the normal operating governor, each auxiliary diesel engine having a maximum
continuous output of 220 kW and over is to be fitted with a separate overspeed device so adjusted
that the speed cannot exceed the maximum rated speed by more than 15%. Provision is to be made
for hand tripping. See 4-6-4/3.15 for pressure-lubricated machines.

3.21 Alternating-current (AC) Generators

3.21.1 Control and Excitation of Generators
Excitation current for generators is to be provided by attached rotating exciters or by static
exciters deriving their source of power from the machine being excited.
3.21.2 Voltage Regulation (2007)
3.21.2(a) Voltage Regulators. A separate regulator is to be supplied for each AC generator. When
it is intended that two or more generators will be operated in parallel, reactive-droop compensating
means are to be provided to divide the reactive power properly between the generators.

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3.21.2(b) Variation from Rated Voltage – Steady Conditions. Each AC generator for ship’s service
driven by its prime mover having governor characteristics complying with 4-6-4/3.17.1 or 4-6-4/3.19.1
is to be provided with an excitation system capable of maintaining the voltage under steady conditions
within plus or minus 2.5% of the rated voltage for all loads between zero and rated load at rated
power factor. These limits may be increased to plus or minus 3.5% for emergency sets.
3.21.2(c) Variation from Rated Voltage – Transient Conditions. Momentary voltage variations
are to be within the range of minus 15% to plus 20% of the rated voltage, and the voltage is to be
restored to within plus or minus 3% of the rated voltage in not more than 1.5 seconds when:
• A load equal to the starting current of the largest motor or a group of motors, but in any case,
at least 60% of the rated current of the generator, and power factor of 0.4 lagging or less, is
suddenly thrown on with the generator running at no load; and
• A load equal to the above is suddenly thrown off.
Consideration can be given to performing the test required by 4-6-4/Table 1, Item 4 according to
precise information concerning the maximum values of the sudden loads instead of the values
indicated above, provided precise information is available. The precise information concerning
the maximum values of the sudden loads is to be based on the power management system
arrangements and starting arrangements provided for the electrical system.
3.21.2(d) Short Circuit Conditions. Under steady-state short-circuit conditions, the generator together
with its excitation system is to be capable of maintaining a steady-state short-circuit current of not
less than three times its rated full load current for a period of two seconds or of such magnitude
and duration as required to properly actuate the associated electrical protective devices.
3.21.3 Parallel Operation
For AC generating sets operating in parallel, the following requirements are to be complied with.
See also 4-6-2/9.5.2 for protection of AC generators in parallel operation.
3.21.3(a) Reactive Load Sharing. The reactive loads of the individual generating sets are not to
differ from their proportionate share of the combined reactive load by more than 10% of the rated
reactive output of the largest generator, or 25% of the rated reactive output of the smallest
generator, whichever is the less.
3.21.3(b) Load Sharing. For any load between 20% and 100% of the sum of the rated output
(aggregate output) of all generators, the load on any generator is not to differ more than 15% of
the rated output in kilowatt of the largest generator or 25% of the rated output in kilowatt of the
individual generator in question, whichever is the less, from its proportionate share of the combined
load for any steady state condition. The starting point for the determination of the foregoing load-
distribution requirements is to be at 75% of the aggregate output with each generator carrying its
proportionate share.
3.21.3(c) Facilities for Load Adjustment. Facilities are to be provided to adjust the governor
sufficiently fine to permit an adjustment of load not exceeding 5% of the aggregate output at normal
frequency.

3.23 Direct-current (DC) Generators

3.23.1 Control and Excitation of Generators
3.23.1(a) Field Regulations. Means are to be provided at the switchboard to enable the voltage of
each generator to be adjusted separately. This equipment is to be capable of adjusting the voltage
of the DC generator to within 0.5% of the rated voltage at all loads between no-load and full-load.
3.23.1(b) Polarity of Series Windings. The series windings of each generator for a two wire DC
system are to be connected to the negative terminal of each machine.
3.23.1(c) Equalizer Connections. See 4-6-4/7.15.3.

242 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
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Section 4 Machinery and Equipment 4-6-4

3.23.2 Voltage Regulation

3.23.2(a) Shunt or Stabilized Shunt-wound Generator. When the voltage has been set at full-load
to its rated value, the removal of the load is not to cause a permanent increase of the voltage
greater than 15% of the rated voltage. When the voltage has been set either at full-load or at no-
load, the voltage obtained at any value of the load is not to exceed the no-load voltage.
3.23.2(b) Compound-wound Generator. Compound-wound generators are to be so designed in
relation to the governing characteristics of the prime mover that with the generator at full-load
operating temperature and starting at 20% load with voltage within 1% of rated voltage, it gives at
full-load a voltage within 1.5% of rated voltage. The average of ascending and descending voltage
regulation curves between 20% load and full-load is not to vary more than 3% from rated voltage.
3.23.2(c) Automatic Voltage Regulators. Ship’s service generators which are of a shunt type are
to be provided with automatic voltage regulators. However, if the load fluctuation does not interfere
with the operation of essential auxiliaries, shunt-wound generators without voltage regulators or
stabilized shunt-wound machines may be used. An automatic voltage regulator will not be required
for the ship’s service generators of an approximately flat-compounded type. Automatic voltage
regulators are to be provided for all service generators driven by variable speed engines used also
for propulsion purposes, whether these generators are of the shunt, stabilized shunt or compound-
wound type.
3.23.3 Parallel Operation
For DC generating sets operating in parallel, the following requirements are to be complied with.
See also 4-6-2/9.7.2 for protection of DC generators in parallel operation.
3.23.3(a) Stability. The generating sets are to be stable in operation at all loads from no-load to
full-load.
3.23.3(b) Load Sharing. For any load between 20% and 100% of the sum of the rated output
(aggregate output) of all generators, the load on any generator is not to differ more than 12% from
the rated output in kilowatts of the largest generator or 25% from the rated output in kilowatts of
the individual generator in question, whichever is the less, from its proportionate share of the
combined load for any steady state condition. The starting point for the determination of the
foregoing load-distribution requirements is to be at 75% of the aggregate output with each
generator carrying its proportionate share.
3.23.3(c) Tripping of Circuit Breaker. DC generators which operate in parallel are to be provided
with a switch which will trip the generator circuit breaker upon functioning of the overspeed device.

5 Accumulator Batteries

5.1 General
5.1.1 Application
All accumulator batteries for engine starting, essential or emergency services are to be constructed
and installed in accordance with the following requirements. Accumulator batteries for services
other than the above are to be constructed and equipped in accordance with good commercial
practice. All accumulator batteries will be accepted subject to a satisfactory performance test
conducted after installation to the satisfaction of the Surveyor.
5.1.2 Sealed Type Batteries
Where arrangements are made for releasing gas through a relief valve following an overcharge
condition, calculations demonstrating compliance with the criteria in 4-6-3/3.7.3 under the expected
rate of hydrogen generation are to be submitted together with the details of installation and mechanical
ventilation arrangements.

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5.1.3 References
5.1.3(a) Emergency Services. For requirements covering emergency services and transitional
source of power, see 4-6-2/5.5.3 and 4-6-2/5.7, respectively.
5.1.3(b) Protection of Batteries. For requirements covering protection of batteries, see 4-6-2/5.9.
5.1.3(c) Battery Installation. For requirements covering battery installation, ventilation of the battery
location and protection from corrosion, see 4-6-3/3.7.
5.1.3(d) Cable Installation. For requirements covering cable installation in the battery room, see
4-6-3/5.23.

5.3 Construction and Assembly

5.3.1 Cells and Filling Plugs
The cells are to be so constructed as to prevent spilling of electrolyte due to an inclination of 40 deg.
from normal. The filling plugs are to be so constructed as to prevent spilling of electrolyte due to
the vessel’s movements such as rolling and pitching.
5.3.2 Crates and Trays
The cells are to be grouped in crates or trays of rigid construction equipped with handles to facilitate
handling. For protection from corrosion, see 4-6-3/3.7.4. The mass of crates or trays are not to
exceed 100 kg (220.5 lb).
5.3.3 Nameplate
Nameplates of corrosion-resistant material are to be provided in an accessible position of each
crate or tray and are to indicate at least the information as listed in 4-6-4/Table 4b.

5.5 Engine-starting Battery

Battery systems for engine-starting purposes may be of the one-wire type and the earth lead is to be carried
to the engine frame. See also 4-2-1/13.9 and 4-6-2/5.15 for main engine starting and the starting arrangement
of the emergency generator, respectively.

7 Switchboards, Distribution Boards, Controllers, etc.

7.1 General
7.1.1 Applications (2010)
Switchboards are to provide adequate control of the generation and distribution of electric power.
The following equipment are to be constructed and tested in accordance with the following
requirements to the satisfaction of the Surveyor.
7.1.1(a) Switchboards. Switchboards for essential services or for services indicated in 4-6-4/Table 11.
7.1.1(b) Motor Controllers. Motor Controllers of 100 kW and over intended for essential services
or for services indicated in 4-6-4/Table 11.
7.1.1(c) Motor Control Centers. Motor control centers with aggregate loads of 100 kW or more
intended for essential services or for services indicated in 4-6-4/Table 11.
7.1.1(d) Battery Charger Units and Uninterruptible Power System (UPS) Units. Battery charger
units of 25 kW and over and uninterruptible power system (UPS) units of 50 kVA intended for
essential services, services indicated in 4-6-4/Table 11, emergency source of power or transitional
source of power.
7.1.1(e) Distribution Boards. Distribution boards associated with the charging or discharging of
the battery system or uninterruptible power system (UPS) in 4-6-4/7.1.1(d).
Switchboard, distribution board, battery charger units, uninterruptible power system (UPS) units, motor
control centers and motor controllers not covered by the above paragraph are to be constructed
and equipped in accordance with good commercial practice, and will be accepted subject to a
satisfactory performance test conducted after installation to the satisfaction of the Surveyor.

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7.1.2 References
7.1.2(a) Inclination. For requirements covering inclination for design condition, see 4-1-1/17.
7.1.2(b) Emergency Switchboard. For requirements covering emergency switchboard, see 4-6-3/5.9.
7.1.2(c) Circuit Breakers. For requirements covering generator circuit breakers, see 4-6-4/11.1.
7.1.2(d) Feeder Protection. For requirements covering feeder protection, see 4-6-2/9.3 to 4-6-2/9.17,
4-6-2/11.3, 4-6-2/13.1.4 and 4-6-2/13.3.3
7.1.2(e) Hull Return and Earthed Distribution System. For requirements covering hull return system
and earthed distribution system, see 4-6-2/7.3 and 4-6-2/7.5, respectively
7.1.2(f) Earthing. For requirements covering earthing connections, see 4-6-3/7.
7.1.2(g) Installation. For requirements covering installation, see 4-6-3/3.9 for switchboard,
4-6-3/3.11 for distribution boards and 4-6-3/3.13 for motor controllers and control centers.
7.1.2(h) Protection Enclosures and its Selection. For requirements covering degree of the protection
and the selection of equipment, see 4-6-1/15 and 4-6-3/3.1, respectively.

7.3 Testing and Inspection

7.3.1 Applications
7.3.1(a) Switchboards (2010). All switchboards intended for essential services or for services
indicated in 4-6-4/Table 11, are to be tested in the presence of and inspected by the Surveyor,
preferably at the plant of the manufacturer. For other switchboards, the tests may be carried out by
the manufacturer whose certificate of tests will be acceptable and is to be submitted upon request
from ABS.
7.3.1(b) Motor Controllers (2010). All motor controllers of 100 kW and over intended for essential
services or for services indicated in 4-6-4/Table 11 are to be tested in the presence of and inspected
by the Surveyor, preferably at the plant of the manufacturer. For other motor controllers, the tests
may be carried out by the manufacturer whose certificate of tests will be acceptable and is to be
submitted upon request from ABS.
7.3.1(c) Motor Control Centers (2010). All motor control centers with aggregate loads of 100 kW
and over intended for essential services or for services indicated in 4-6-4/Table 11 are to be tested
in the presence of and inspected by the Surveyor, preferably at the plant of the manufacturer. For
other motor control centers, the tests may be carried out by the manufacturer whose certificate of
tests will be acceptable and is to be submitted upon request from ABS.
7.3.1(d) Battery Charger Units, Uninterruptible Power System (UPS) Units, and Distribution
Boards (2010). Battery charger units of 25 kW and over, uninterruptible power system (UPS) units
of 50 kW and over, and distribution boards [associated with the charging or discharging of the
battery system or uninterruptible power system (UPS)] are used for essential services (see 4-6-1/3.3),
services indicated in 4-6-4/Table 11, emergency source of power (see 4-6-2/5), and transitional
source of power (see 4-6-2/5.7) are to be tested in the presence of and inspected by the Surveyor,
preferably at the plant of the manufacturer. For all other battery charger units, uninterruptible power
system (UPS) units, and distribution boards, the tests may be carried out by the manufacturer
whose certificate of tests will be acceptable and is to be submitted upon request from ABS.
7.3.1(e) Test Items. Tests are to be carried out in accordance with the requirements in 4-6-4/Table 5.
7.3.2 Special Testing Arrangements
In cases where all of the required tests are not carried out at the plant of the manufacturer, the
Surveyor is to be notified and arrangements are to be made so that the remaining tests may be
witnessed.

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7.5 Insulation Resistance Measurement

The insulation resistance between current-carrying parts (connected together for the purpose of this test)
and earth and between current-carrying parts of opposite polarity is to be measured at a DC voltage of not
less than 500 volts before and after the dielectric strength tests. The insulation resistance measurement
after the dielectric strength tests is to be carried out before components which have been disconnected for
the dielectric tests are reconnected, and the insulation resistance is not to be less than 1 megohm.

7.7 Dielectric Strength of Insulation

The dielectric strength of the insulation is to be tested for 60 seconds by an alternating voltage applied in
accordance with 4-6-4/Table 5 between:
i) All live parts and the interconnected, exposed conductive parts, and
ii) Each phase and all other phases connected for this test to the interconnected exposed conductive
parts of the unit.
The test voltage at the moment of application is not to exceed 50% of the values given in 4-6-4/Table 5. It
is to be increased steadily within a few seconds to the required test voltage and maintained for 60 seconds.
Test voltage is to have a sinusoidal waveform and a frequency between 45 Hz and 60 Hz.
7.7.1 Production-line Apparatus
Standard apparatus produced in large quantities for which the standard test voltage is 2500 volts or
less may be tested for one second with a test voltage 20% higher than the one-minute test voltage.
7.7.2 Devices with Low Insulation Strength
Certain devices such as potential transformers having inherently lower insulation strength are to
be disconnected during the test.

7.9 Construction and Assembly

7.9.1 Enclosures and Assemblies
Enclosures and assemblies are to be constructed of steel or other suitable, incombustible,
moisture-resistant materials and reinforced as necessary to withstand the mechanical, electrical
(magnetic) and thermal stresses likely to be encountered in service, and are to be protected against
corrosion. No wood is to be used, except for hardwood for nonconducting hand rails. Insulating
materials are to be flame retardant and moisture resistant. The supporting framework is to be of
rigid construction.
7.9.2 Dead Front
The dead-front type is to be used. Live-front type is not acceptable, regardless of the voltage ratings.
7.9.3 Mechanical Strength
All levers, handles, hand wheels, interlocks and their connecting links, shafts and bearings for the
operation of switches and contactors are to be of such proportions that they will not be broken or
distorted by manual operation.
7.9.4 Mechanical Protection (2004)
The sides and the rear and, where necessary, the front of switchboards are to be suitably guarded.
Exposed live parts having voltages to earth exceeding a voltage of 55 volts DC or 55 volts AC
r.m.s. between conductors are not to be installed on the front of such switchboards. Unless the
switchboard is installed on an electrically insulated floor, non-conducting mats or gratings are to
be provided at the front and rear of the switchboard. Where the floor on which the switchboard is
installed is of electrically insulated construction, the insulation level of the floor to the earth is to
be at least 50 MΩ. A notice plate is to be posted at the entrance to the switchboard room or on the
switchboard front panel to state that the floor in the room is of electrically insulated construction.
Drip covers are to be provided over switchboards when subject to damage by leaks or falling objects.

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7.11 Bus Bars, Wiring and Contacts

7.11.1 Design
Copper bar is to be used for main and generator bus in the switchboard. Other materials and
combination of materials will be specially considered. Generator bus bars are to be designed on the
basis of maximum generator rating. All other bus bars and bus-bar connections are to be designed
for at least 75% of the combined full-load rated currents of all apparatus that they supply, except
that when they supply one unit or any group of units in continuous operation, they are to be designed
for full load.
7.11.2 Operating Temperature of Bus Bars
Bus bars are to be proportioned to avoid temperature which will affect the normal operation of
electrical devices mounted on the board.
7.11.3 Short Circuit Rating
Circuit breakers and bus bars are to be mounted, braced and located so as to withstand the thermal
effects and mechanical forces resulting from the maximum prospective short circuit current.
Switchboard instruments, controls, etc. are to be located with respect to circuit breakers so as to
minimize the thermal effects due to short circuit currents.
7.11.4 Internal Wiring
Instrument and control wiring is to be of the stranded type and is to have heat-resisting and flame-
retarding insulation. Wiring from hinged panels is to be of the extra-flexible type.
7.11.5 Arrangement
7.11.5(a) Accessibility. The arrangement of bus bars and wiring on the back is to be such that all
lugs are readily accessible.
7.11.5(b) Locking of Connections (2004). All nuts and connections are to be fitted with locking
devices to prevent loosening due to vibration. Bolted bus bar connections are to be suitably treated
(e.g., silver plating) to avoid deterioration of electrical conductivity over time.
7.11.5(c) Soldered Connections. Soldered connections are not to be used for connecting or
terminating any wire or cable of nominal cross-sectional area of greater than 2.5 mm2 (4,933 circ.
mils). Soldered connections, where used, are to have a solder contact length at least 1.5 times the
diameter of the conductor.
7.11.6 Clearances and Creepage Distances
Bare main bus bars, but not including the conductors between the main bus bars and the supply side
of outgoing units, are to have minimum clearances (in air) and creepage distances (across surfaces)
in accordance with 4-6-4/Table 6.
7.11.7 Terminals (2009)
Terminals or terminal rows for systems of different voltages are to be clearly separated from each
other. The rated voltage is to be clearly indicated at least once for each group of terminals which
have been separated from the terminals with other voltage ratings. Terminals with different voltage
ratings, each not exceeding 50 V DC or 50 V AC may be grouped together. Each terminal is to
have a nameplate indicating the circuit designation.

7.13 Control and Protective Devices

7.13.1 Circuit-disconnecting Devices
7.13.1(a) Systems Exceeding 55 Volts. Distribution boards, chargers or controllers for distribution
to motors, appliances, and lighting or other branch circuits are to be fitted with multipole circuit
breakers or a multipole switch-fuse combination in each unearthed conductor.
7.13.1(b) System of 55 Volts and Less. For distribution boards, chargers or controllers where voltage
to earth or between poles does not exceed 55 volts DC or 55 volts AC r.m.s., the fuses may be
provided without switches.

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7.13.1(c) Disconnect Device. The rating of the disconnecting device is to be coordinated with the
voltage and current requirements of the load. The disconnect device is to indicate by position of
the handle, or otherwise, whether it is open or closed.
7.13.2 Arrangement of Equipment
7.13.2(a) Air Circuit Breakers. Air circuit breaker contacts are to be kept at least 305 mm (12 in.)
from the vessel’s structure unless insulation barriers are installed.
7.13.2(b) Voltage Regulators. Voltage regulator elements are to be provided with enclosing cases
to protect them from damage.
7.13.2(c) Equipment Operated in High Temperature. Where rheostats or other devices that may
operate at high temperatures are mounted on the switchboard, they are to be naturally ventilated
and so located or isolated by barriers as to prevent excessive temperature of adjacent devices.
When this cannot be accomplished, the rheostat or other device is to be mounted separately from
the switchboard.
7.13.2(d) Accessibility to Fuses. All fuses, except for instrument and control circuits, are to be
mounted on or be accessible from the front of the switchboard.
7.13.2(e) Protective Device for Instrumentation. All wiring on the boards for instrumentation is
to be protected by fuses or current limiting devices. See 4-6-2/9.17.
7.13.2(f) Wearing Parts. All wearing parts are to be accessible for inspection and readily renewable.
7.13.3 Markings
Identification plates are to be provided for each piece of apparatus to indicate clearly its service.
Identification plates for feeders and branch circuits are to include the circuit designation and the
rating of the fuse or circuit-breaker trip setting required by the circuit.

7.15 Switchboards
In addition to 4-6-4/7.1 to 4-6-4/7.13, as applicable, the switchboards for essential or emergency services
are to comply with the following requirements.
7.15.1 Handrails
Insulated handrail or insulated handles are to be provided on the front of the switchboard. Similarly,
where access to the rear is required, insulated handrail or insulated handles are also to be fitted on
the rear of the switchboard.
7.15.2 Main Bus Bar Subdivision (1 July 1998)
Vessels with the keel laid or in similar stage of construction on or after 1 July 1998 are to meet the
following requirements. Where the main source of electrical power is necessary for propulsion of
the vessel, the main bus bar is to be subdivided into at least two parts which is to be normally
connected by circuit breaker or other approved means. As far as practicable, the connection of
generating sets and any other duplicated equipment is to be equally divided between the parts.
7.15.3 Equalizer Circuit for Direct-current (DC) Generators
7.15.3(a) Equalizer Main Circuit. The current rating of the equalizer main circuit for direct-
current (DC) generators is not to be less than half of the rated full-load current of the generator.
7.15.3(b) Equalizer Bus Bars. The current rating of the equalizer bus bars is not to be less than
half of the rated full-load current of the largest generator in the group.
7.15.4 Equipment and Instrumentation (2005)
Equipment and instrumentation are to be provided in accordance with 4-6-4/Table 7. They are to
be suitable for starting, stopping, synchronizing and paralleling each generator set from the main
switchboard. They may be mounted on the centralized control console, if the main switchboard is
located in the centralized control station.

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7.17 Motor Controllers and Control Centers

In addition to 4-6-4/7.1 to 4-6-4/7.13, as applicable, the motor controllers and control centers for essential
or emergency services are to comply with the following requirements.
7.17.1 Enclosures and Assemblies
The following materials are acceptable for the enclosures:
• Cast metal, other than die-cast metal, at least 3 mm (1/8 in.) thick at every point.
• Nonmetallic materials which have ample strength, are noncombustible and non-absorptive
(e.g., laminated phenolic material).
• Sheet metal of adequate strength.
Motor control centers are to be constructed so that they are secured to a solid foundation, be self-
supported, or be braced to the bulkhead.
7.17.2 Disconnect Switches and Circuit Breakers (1999)
Means are to be provided for the disconnection of the full load from all live poles of supply of every
motor rated at 0.5 kW or above and its controlgear. Where the controlgear is mounted on or adjacent
to a main or auxiliary distribution switchboard, a disconnecting switch in the switchboard may be
used for this purpose. Otherwise, a disconnecting switch within the controlgear enclosure or a separate
enclosed disconnecting switch is to be provided. Disconnect switches and circuit breakers are to
be operated without opening the enclosures in which they are installed.
7.17.3 Auto-starters
Alternating-current (AC) motor manual auto-starters with self-contained auto-transformers are to
be provided with switches of the quick-make-and-break type, and the starter is to be arranged so
that it will be impossible to throw to the running position without having first thrown to the
starting position. Switches are to be preferably of the contactor or air-break-type.

7.19 Battery Systems and Uninterruptible Power Systems (UPS) (2008)

In addition to 4-6-4/7.1 to 4-6-4/7.13, as applicable, equipment for essential, emergency, and transitional sources
of power services are to comply with the following requirements. Such equipment would include the battery
charger unit, uninterruptible power system (UPS) unit, and the distribution boards associated with the charging
or discharging of the battery system or uninterruptible power system (UPS).
7.19.1 Definitions (2008)
Uninterruptible Power System (UPS) – A combination of converters, switches and energy storage
means, for example batteries, constituting a power system for maintaining continuity of load power
in case of input power failure.
Off-line UPS unit – A UPS unit where under normal operation the output load is powered from the
bypass line (raw mains) and only transferred to the inverter if the bypass supply fails or goes outside
preset limits. This transition will invariably result in a brief (typically 2 to 10 ms) break in the load
supply.
Line interactive UPS unit – An off-line UPS unit where the bypass line switch to stored energy power
when the input power goes outside the preset voltage and frequency limits.
On-line UPS unit – A UPS unit where under normal operation the output load is powered from the
inverter, and will therefore continue to operate without break in the event of the supply input failing
or going outside preset limits.
DC UPS unit – A UPS unit where the output is in DC (direct current).
7.19.2 Battery Charging Rate (2008)
Except when a different charging rate is necessary and is specified for a particular application, the
charging facilities are to be such that the completely discharged battery can be recharged to 80%
capacity in not more than 10 hours. See also 4-6-4/7.19.6(c)

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7.19.3 Discharge Protection (2008)

An acceptable means, such as reverse current protection, is to be provided for preventing a failed
component in the battery charger unit or uninterruptible power system (UPS) unit from discharging
the battery.
7.19.4 Design and Construction (2008)
7.19.4(a) Construction. Battery charger units and uninterruptible power system (UPS) units are
to be constructed in accordance with the IEC 62040 Series, or an acceptable and relevant national
or international standard.
7.19.4(b) Operation. The operation of the UPS is not to depend upon external services.
7.19.4(c) Type. The type of UPS unit employed, whether off-line, line interactive or on-line, is to
be appropriate to the power supply requirements of the connected load equipment.
7.19.4(d) Continuity of Supply. An external bypass is to be provided to account for a failure within
the uninterruptible power system (UPS). For battery charger units and DC UPS units, see
4-6-2/7.1.6(c).
7.19.4(e) Monitoring and Alarming. The battery charger unit or uninterruptible power system
(UPS) unit is to be monitored and audible and visual alarm is to be given in a normally attended
location for the following.
• Power supply failure (voltage and frequency) to the connected load
• Earth fault,
• Operation of battery protective device,
• When the battery is being discharged, and
• When the bypass is in operation for on-line UPS units. When changeover occurs, for battery
charger units and DC UPS units required to comply with 4-6-2/7.1.6(c).
7.19.5 Location (2008)
7.19.5(a) Location. The UPS unit is to be suitably located for use in an emergency. The UPS unit
is to be located as near as practical to the equipment being supplied, provided the arrangements comply
with all other Rules, such as 4-6-3/3.7, 4-6-3/3.9, 4-6-3/3.11, and 4-6-3/3.13 for location of electrical
equipment.
7.19.5(b) Ventilation. UPS units utilizing valve regulated sealed batteries may be located in
compartments with normal electrical equipment, provided the ventilation arrangements are in
accordance with the requirements of 4-6-3/3.7. Since valve regulated sealed batteries are considered
low-hydrogen-emission batteries, calculations are to be submitted in accordance with 4-6-3/3.7.2(d)
to establish the gas emission performance of the valve regulated batteries compared to the standard
lead acid batteries. Arrangements are to be provided to allow any possible gas emission to be led
to the weather, unless the gas emission performance of the valve regulated batteries does not
exceed that of standard lead acid batteries connected to a charging device of 0.2 kW.
7.19.5(c) Battery Installation. For battery installation arrangements, see 4-6-3/3.7.
7.19.6 Performance (2008)
7.19.6(a) Duration. The output power is to be maintained for the duration required for the connected
equipment as stated in 4-6-2/5.3 for emergency services and 4-6-2/5.7 of transitional source of power,
as applicable.
7.19.6(b) Battery Capacity. No additional circuits are to be connected to the battery charger unit
or UPS unit without verification that the batteries have adequate capacity. The battery capacity is,
at all times, to be capable of supplying the designated loads for the time specified in 4-6-4/7.19.6(a).
7.19.6(c) Recharging. On restoration of the input power, the rating of the charging facilities are
to be sufficient to recharge the batteries while maintaining the output supply to the load equipment.
See also 4-6-4/7.19.2.

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7.19.7 Testing and Survey (2008)

7.19.7(a) Surveys. Equipment units are to be surveyed during manufacturing and testing in
accordance with 4-6-4/7.3.1.
7.19.7(b) Testing. Appropriate testing is to be carried out to demonstrate that the battery charger
units and uninterruptible power system (UPS) units are suitable for the intended environment. This
is expected to include as a minimum the following tests:
• Functionality, including operation of alarms;
• Temperature rise;
• Ventilation rate;
• Battery capacity
7.19.7(c) Test upon power input failure. Where the supply is to be maintained without a break
following a power input failure, this is to be verified after installation by practical test.

9 Transformers

9.1 General
9.1.1 Applications (2004)
All transformers which serve for essential or emergency electrical supply are to be constructed,
tested and installed in accordance with the following requirements. Transformers other than the above
services, auto-transformers for starting motors or isolation transformers are to be constructed and
equipped in accordance with good commercial practice. All transformers are to be of the dry and air
cooled type. The use of liquid immersed type transformers will be subject to special consideration.
Transformers other than for essential or emergency services will be accepted subject to a satisfactory
performance test conducted after installation to the satisfaction of the Surveyor.
9.1.2 References
9.1.2(a) Power Supply Arrangement. For requirements covering arrangement of power supply
through transformers to ship’s service systems, see 4-6-2/7.1.6.
9.1.2(b) Protection. For requirements covering protection of transformers, see 4-6-2/9.15.
9.1.2(c) Protection Enclosures and its Selection. For requirements covering selection of the
protection enclosures for location conditions, see 4-6-3/3.1.1.
9.1.3 Forced Cooling Arrangement (Air or Liquid)
Where forced cooling medium is used to preclude the transformer from exceeding temperatures
outside of its rated range, monitoring and alarm means are to be provided and arranged so that an
alarm activates when pre-set temperature conditions are exceeded. Manual or automatic arrangements
are to be made to reduce the transformer load to a level corresponding to the cooling available.

9.3 Temperature Rise

The design temperature rise of insulated windings based on an ambient temperature of 40°C (104°F) is not
to exceed the values listed in 4-6-4/Table 8. If the ambient temperature exceeds 40°C (104°F), the transformer is
to be derated so that the total temperature based on the above temperature rises is not exceeded. Temperatures
are to be taken by the resistance method of temperature determination. Temperature rises for insulation
material above 180°C (356°F) will be considered in accordance with 4-6-1/13.11.

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9.5 Construction and Assembly

9.5.1 Windings
All transformer windings are to be treated to resist moisture, sea atmosphere and oil vapors.
9.5.2 Terminals
Terminals are to be provided in an accessible position. The circuit designation is to be clearly marked
on each terminal connection. The terminals are to be so spaced or shielded that they can not be
accidentally earthed, short-circuited or touched.
9.5.3 Nameplate
Nameplates of corrosion-resistant material are to be provided in an accessible position of the
transformer and are to indicate at least the information as listed in 4-6-4/Table 4c.
9.5.4 Prevention of the Accumulation of Moisture (2002)
Transformers of 10 kVA/phase and over are to be provided with effective means to prevent
accumulation of moisture and condensation within the transformer enclosure where the transformer
is disconnected from the switchboard during standby (cold standby). Where it is arranged that the
transformer is retained in an energized condition throughout a period of standby (hot standby), the
exciting current to the primary winding may be considered as a means to meet the above purpose.
In case of hot standby, a warning plate is to be posted at or near the disconnecting device for the
primary side feeder to the transformer.

9.7 Testing (1999)

For single-phase transformers rated 1 kVA and above or three-phase transformers rated 5 kVA and above
intended for essential or emergency services, the following tests are to be carried out by the transformer’s
manufacturer in accordance with a recognized standard whose certificate of test is to be submitted for
review upon request.
i) Measurement of winding resistance, voltage ratio, impedance voltage, short circuit impedance,
insulation resistance, load loss, no load loss and excitation current, phase relation and polarity.
ii) Dielectric strength.
iii) Temperature rise (required for one transformer of each size and type). See 4-6-4/9.3.

11 Other Electric and Electronics Devices

11.1 Circuit Breakers

11.1.1 General
Circuit breakers are to be constructed and tested to comply with IEC Publication 60947-2 or other
recognized standard. The tests may be carried out by the manufacturer whose certificate of tests
will be acceptable and is to be submitted upon request from ABS. Circuit breakers of the thermal
type are to be calibrated for an ambient-air temperature, as provided in 4-6-1/17.
Note: Where thermal-type breakers are mounted within enclosures, it is pointed out that the temperature within
the enclosure may exceed the designated ambient-air temperature.

11.1.2 Mechanical Property

Arc-rupturing and main contacts of all open frame circuit breakers are to be self-cleaning.
11.1.3 Isolation
The electrical system is to be arranged so that portions may be isolated to remove circuit breakers
while maintaining services necessary for propulsion and safety of the vessel, or circuit breakers
are to be mounted or arranged in such a manner that the breaker may be removed from the front
without disconnecting the copper or cable connections or without de-energizing the supply to the
breaker.

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11.3 Fuses
Fuses are to be constructed and tested to comply with IEC Publication 60269 or other recognized standard.
The tests may be carried out by the manufacturer whose certificate of tests will be acceptable and is to be
submitted upon request from ABS. All components of the fuse are to be resistant to heat, mechanical stresses
and corrosive influences which may occur in normal use.

11.5 Semiconductor Converters

11.5.1 General
The requirements in this subsection are applicable to static converters for essential and emergency
services using semiconductor rectifying elements such as diodes, reverse blocking triodes thyristors,
etc. The tests may be carried out by the manufacturer whose certificate of tests will be acceptable
and is to be submitted upon request from ABS. All semiconductor converters will be accepted subject
to a satisfactory performance test conducted after installation to the satisfaction of the Surveyor.
11.5.2 Cooling Arrangements
Semiconductor converters are preferably to be of a dry and air-cooled type. Where semiconductor
converters are of a liquid-immersed type, a liquid over-temperature alarm and gas over-pressure
protection devices are to be provided. If provision is made for breathing, a dehydrator is to be
provided. Where arrangement for the forced cooling is provided, the circuit is to be designed so
that power cannot be applied to, or retained on, converter stacks unless effective cooling is maintained.
11.5.3 Accessibility
Semiconductor converter stacks or semiconductor components are to be mounted in such a manner
so that they can be removed from equipment without dismantling the complete unit.
11.5.4 Nameplate
A nameplate or identification is to be provided on the semiconductor converter and is to indicate
at least the information as listed in 4-6-4/Table 4d.

11.7 Cable Junction Boxes

11.7.1 General
The design and construction of the junction boxes are to be in compliance with 4-6-4/11.7.2 or
other recognized standard. The tests may be carried out by the manufacturer whose certificate of
tests will be acceptable and is to be submitted upon request from ABS.
11.7.2 Design and Construction
Live parts are to be mounted on durable flame-retardant moisture-resistant material, of permanently
high dielectric strength and high resistance. The live parts are to be so arranged by suitable spacing
or shielding with flame-retardant insulating material that short-circuit cannot readily occur between
conductors of different polarity or between conductors and earthed metal. Junction boxes are to be
made of flame-retardant material and are to be clearly identified, defining their function and voltage.

13 Cables and Wires

13.1 Cable Construction

13.1.1 General (2010)
Electric cables are to have conductors, insulation and moisture-resistant jackets, in accordance with
IEC Publication 60092-350, 60092-351, 60092-352, 60092-353, 60092-354, 60092-359, 60092-373,
60092-374, 60092-375, 60092-376, or IEEE Std. 45. Other recognized marine standards will also
be considered. The tests may be carried out by the manufacturer whose certificate of tests will be
acceptable and is to be submitted upon request from ABS. Network cables are to comply with a
recognized industry standard. Conductors are to be of copper and stranded in all sizes. Conductors
are not to be less than the following in cross sectional size:

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• 1.0 mm2 (1,973.5 circ. mils) for power and lighting,

• 0.5 mm2 (986.8 circ. mils) for control cables,
• 0.5 mm2 (986.8 circ. mils) for essential or emergency signaling and communications cables,
except for those assembled by the equipment manufacturer, and
• 0.35 mm2 (690.8 circ. mils) for telephone cables for nonessential communication services,
except for those assembled by the equipment manufacturer.
See 4-6-4/Table 10 for current carrying capacity for insulated copper wires and cables.
For electric cables in hazardous areas, the electric cable construction and the cable glands are to
achieve the appropriate seal, such that gas can not migrate through the cable.
Note: See clause 3.16 and clause 4.6 of IEC 60092-350 concerning the provision of an extruded impervious
inner sheath that will prevent the migration of gas through the cable.

13.1.2 Flame Retardant Property

13.1.2(a) Standards. All electric cables are to be at least of a flame retardant type complying
with the following:
• (1999) Depending on the intended installation, cables constructed to IEC Publication 60092
standards are to comply with the flammability criteria of IEC Publication 60332-3, category
A/F or A/F/R, or
• Cables constructed to IEEE Std. 45 are to comply with the flammability criteria of that standard,
or
• Cables constructed to another recognized marine standard, where specially approved, are to
comply with the flammability criteria of IEEE Std. 45 or other acceptable standards.
Consideration will be given to the special types of cables, such as radio frequency cable, which do
not comply with the above requirements.
13.1.2(b) Alternative Arrangement (2005). Flame-retardant marine cables, including network cables,
which have not passed the above-mentioned bunched cable flammability criteria may be considered,
provided that the cable is treated with approved flame-retardant material or the installation is
provided with approved fire stop arrangements. Special consideration may be given to the flame
retardancy of special types of cables, such as radio frequency cables. When specifically approved,
bus duct may be used in lieu of cable.
13.1.3 Fire Resistant Property (2008)
Where electrical cables are required to be fire resistant, they are to comply with the requirements
of IEC Standard 60331-31 for cables greater than 20 mm overall in diameter, otherwise they are to
comply with the IEC Standard 60331-21 for cable diameters 20 mm or less. For special cables,
requirements in the following standards may be used:
• IEC Standard 60331-23: Procedures and requirements – Electric data cables
• IEC Standard 60331-25: Procedures and requirements – Optical fiber cables
Cables complying with alternative national standards suitable for use in a marine environment
may be considered. Fire resistant type cables are to be easily distinguishable. See also 4-6-3/3.2.9
and 4-6-3/5.17.
13.1.4 Insulation Material
All electrical cables for power, lighting, communication, control and electronic circuits are to have
insulation suitable for a conductor temperature of not less than 60°C (140°F). See 4-6-4/Table 9
for types of cable insulation.
13.1.5 Armor for Single-conductor Cables
The armor is to be nonmagnetic for single-conductor alternating-current cables.

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13.1.6 Fiber Optic Cables

Fiber optic cables are to be constructed and tested to a recognized fiber optic cable construction
standard acceptable to ABS. The requirements of flame retardancy for the electrical cables are
applicable to the fiber optic cables. The construction of the fiber optic cable which may pass
through or enter a hazardous area is to be such that escape of gases to a safe area is not possible
through the cable.

13.3 Portable and Flexing Electric Cables

Unless otherwise required in the Rules, cables for portable equipment and cables subject to flexing service
need not be armored.

13.5 Mineral-insulated Metal-sheathed Cable

Mineral-insulated cable provided with approved fittings for terminating and connecting to boxes, outlets
and other equipment may be used for any service up to 600 volts and may be used for feeders and branch
circuits in both exposed and concealed work in dry or wet locations. The moisture-resisting jacket (sheath)
of mineral-insulated metal-sheathed cable exposed to corrosive conditions is to be made of or protected by
materials suitable for those conditions.

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TABLE 1
Factory Test Schedule for Generators and Motors ≥ 100 kW (135 hp)
[See 4-6-4/3.3.1(a)] (2003)
AC generators AC motors DC machines
Tests Type Routine Type Routine Type Routine
test (1) test (2) test (1) test (2) test (1) test (2)
1 Visual inspection. x x x x x x
2 Insulation resistance
x x x x x x
measurement.
3 Winding resistance
x x x x x x
measurement.
4 Verification of voltage
x x(3)
regulation system.
5 Rated load test and temperature
x x x
rise measurement.
(4) (4)
6 Overload/over-current test. x x x x x x(4)
7 Verification of steady short
x
circuit condition. (5)
8 Over-speed test. x x x(6) x(6) x(6) x(6)
9 Dielectric strength test. x x x x x x
(7)
10 Running balance test. x x x x x x
11 Verification of degree of
x x x
protection.
12 Bearing check after test. x x x x x x
13 Air gap measurement. x x x x
14 Commutation check. x
Notes:
1 Type tests apply to prototype machines or to at least the first of a batch of machines.
2 Machines to be routine tested are to have reference to the machine of the same type that has passed a type test.
Reports of routine tested machines are to contain manufacturers’ serial numbers of the type tested machines and
the test results.
3 Only functional test of voltage regulator system.
4 Applicable only to generators and motors ≥ 100 kW (135 hp) for essential services.
5 Verification at steady short circuit condition applies to synchronous generators only.
6 Where so specified and agreed upon between purchaser and manufacturer. Not required for squirrel cage motors.
7 Static balance (machine rated 500 rpm or less) or dynamic balance (over 500 rpm) will be accepted in lieu of the
specified test on machines to be close-coupled to engines and supplied without shaft and/or bearings, or with incomplete
set of bearings.

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TABLE 2
Dielectric Strength Test for Rotating Machines [See 4-6-4/3.9]
Item Machine or Part Test Voltage (AC r.m.s.)
1 Insulated windings of rotated machines having rated output 500 V + twice the rated voltage.
less than 1 kVA, and of rated voltage less than 100 V with the
exception of those in items 4 to 8.
2 Insulated windings of rotating machines having rated output 1,000 V + twice the rated voltage with minimum of 1,500 V
less than 10,000 kVA with the exception of those in items 1 (See Note 1).
and 4 to 8 (See Note 2).
3 (1999) Insulated windings of rotating machines having rated 1,000 V + twice the rated voltage.
output 10,000 kVA or more, and of rated voltage (see Note 1)
up to 24,000 V with the exception of those in items 4 to 8 (see
Note 2).
4 Separately-excited field windings of DC machines. 1,000 V + twice the maximum rated circuit voltage with
minimum of 1,500 V (See Note 1).
5 Field windings of synchronous generators and synchronous
motors.
a) Field windings of synchronous generators Ten times the rated excitation voltage with a minimum of
1,500 V and a maximum of 3,500 V.
b) When the machine is intended to be started with the field Ten times the rated excitation voltage with a minimum of
winding short-circuited or connected across a resistance of 1,500 V and a maximum of 3,500 V.
value less than ten times the resistance of winding.
c) When the machine will be started either with: 1,000 V + twice the maximum value of the voltage with a
– the field winding connected across resistance or more than minimum of 1,500 V
ten times the field winding resistance, or – between the terminals of the field winding,
– the field windings on open circuit or without a field dividing or
switch. – between the terminals of any section for a sectionalized field
winding,
which will be occurred under the specified starting conditions
(see Note 3).
6 Secondary (usually rotor) windings of induction motors or
synchronous induction motors if not permanently short-
circuited (e.g., if intended for rheostatic starting)
a) For non-reversing motors or motors reversible from standstill 1,000 V + twice the open-circuit standstill voltage as
only. measured between slip-rings or secondary terminals with rated
voltage applied to the primary windings.
b) For motors to be reversed or braked by reversing the primary 1,000 V + four times the open-circuit standstill secondary
supply while the motor is running. voltage as defined in item 6.a. above.
7 Exciters (except as listed below) As for windings to which they are connected. 1,000 V + twice
Exception 1—Exciters of synchronous motors (including the rated exciter voltage with a minimum of 1,500 V.
synchronous induction motors) if connected to earth or
disconnected from the field winding during starting
Exception 2—Separately excited field windings of exciters
(see Item 4 above).
8 Assembled group of machines and apparatus. A repetition of the tests in items 1 to 7 above is to be avoided
if possible. But, if a test on an assembled group of several
pieces of new apparatus, each one is made, the test voltage to
be applied to such assembled group is to be 80% of the lowest
test voltage appropriate for any part of the group (see Note 4).

Notes:
1 For two-phase windings having one terminal in common, the rated voltage for the purpose of calculating the test
voltage is to be taken as 1.4 times the voltage of each separate phase.
2 High-voltage tests on machines having graded insulation is to be subject to special consideration.
3 The voltage, which is occurred between the terminals of field windings or sections thereof under the specified starting
conditions, may be measured at any convenient reduced supply voltage. The voltage so measured is to be increased
in the ratio of the specified starting supply voltage to the test supply voltage.
4 For windings of one or more machines connected together electrically, the voltage to be considered is the maximum
voltage that occurs in relation to earth.

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TABLE 3
Limits of Temperature Rise for Air-Cooled Rotating Machines
[See 4-6-4/3.11.1] (2007)
Ambient Temperature = 50°C (1)

Temperature Limit of Temperature Rise, °C

Item for Class of Insulation
Part of Machine Measuring
No.
Method A E B F H
AC windings of machines having rated output of Resistance 50 — 70 90 115
a) 5,000 kW (or kVA) or more Embedded temp.
55 — 75 95 120
detector
AC windings of machines having rated output above Resistance 50 65 70 95 115
1
b) 200 kW (or kVA) but less than 5,000 kW (or kVA) Embedded temp.
55 — 80 100 120
detector.
AC windings of machines having rated outputs of
c) Resistance 50 65 70 95 115
200 kW (or kVA) or less (2)
Thermometer 40 55 60 75 95
2 Windings of armatures having commutators
Resistance 50 65 70 95 115

Field windings of AC and DC machines having DC Thermometer 40 55 60 75 95

3
excitation, other than those in item 4 Resistance 50 65 70 95 115
Field winding of synchronous machines with
cylindrical rotors having DC excitation winding
a) Resistance — — 80 100 125
embedded in slots, except synchronous induction
motors
Thermometer 40 55 60 75 95
Stationary field windings of AC machines having Resistance 50 65 70 95 115
b)
more than one layer Embedded temp.
— — 80 100 125
4 detector.
Low resistance field winding of AC and DC Thermometer 50 65 70 90 115
c) machines and compensating windings of DC
machines having more than one layer Resistance 50 65 70 90 115
Single-layer windings of AC and DC machines with Thermometer 55 70 80 100 125
d) exposed bare or varnished metal surfaces and single
layer compensating windings of DC machines (3) Resistance 55 70 80 100 125

5 Permanently short-circuited windings

Magnetic cores and all structural components, The temperature rise of any parts is not to be detrimental to the
6 whether or not in direct contact with insulation insulating of that part or to any other part adjacent to it.
(excluding bearings)
The temperature rise of any parts is not to be detrimental to the
insulating of that part or to any other part adjacent to it.
Commutators, slip-rings and their brushes and
7 Additionally, the temperature is not to exceed that at which the
brushing
combination of brush grade and commutator/slip-ring materials
can handle the current over the entire operating range.
Notes
1 The limit of temperature rise in the above Table is based on an ambient temperature of 50°C in accordance with
IEC Publication 60092-101. For rotating machines based on a 45°C ambient, the temperature rises may be
increased by 5°C. (See 4-6-4/3.11.2).
2 With application of the superposition test method to windings of machines rated 200 kW (or kVA) or less with
insulation classes A, E, B or F, the limits of temperature rise given for the resistance method may be increased by 5°C.
3 Also includes multiple layer windings provided that the under layers are each in contact with the circulating
coolant.

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TABLE 4 Nameplates
a. Rotating Machines [See 4-6-4/3.13.9] b. Accumulator Battery [See 4-6-4/5.3.3]

The manufacturer’s name The manufacturer’s name

The manufacturer’s serial number (or identification mark) The type designation
The year of manufacture The rated voltage
Type of Machine (Generator or motor, etc.) The ampere-hour rating at a specific rate of discharge
Degree of protection enclosures (by IP code) The specific gravity of the electrolyte
Class of rating or duty type (in the case of a lead-acid battery, the specific gravity when
The rated output the battery is fully charged).
The rated voltage
The rated current and type of current (AC or DC) c. Transformer [See 4-6-4/9.5.3]
The rated speed (r.p.m.) or speed range
The class of insulation or permissible temperature rise The manufacturer’s name
The ambient temperature The manufacturer’s serial number (or identification mark)
The year of manufacture
Number of phase (for AC machines) The number of phases
The rated frequency (for AC machines) The rated power
Power factor (for AC machines) The rated frequency
Type of winding (for DC machines) The rated voltage in primary and secondary sides
The rated current in primary and secondary sides
Exciter voltage (for synchronous machines or DC machines The class of insulation or permissible temperature rise
with separate excitation) The ambient temperature
Exciter current at rating (for synchronous machines or DC
machines with separate excitation) d. Semiconductor Converter [See 4-6-4/11.5.4]
Open-circuit voltage between slip-rings and the slip-ring
current for rated conditions (for wounded-rotor induction The manufacturer’s name
machines) The identification number of the equipment

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TABLE 5
Factory Testing Schedule for Switchboards, Chargers, Motor Control Centers and
Controllers [See 4-6-4/7.3.1]
1 Insulation resistance measurements in accordance with 4-6-4/7.5.
2 Dielectric strength test in accordance with 4-6-4/7.7 and the table below.
3 (1998) Protective device tripping test, such as overcurrent tripping, emergency tripping, preferential tripping, etc.
4 Inspection of the assembly including inspection of wiring and, if necessary, electrical operation test.

Standard Test Voltage for Dielectric Strength Test

Dielectric Test
Rated Insulation Voltage Voltage AC r.m.s.
Up to and including 12 V 250 V
over 12 V to 60 V inclusive 500 V
over 60 V to 300 V inclusive 2000 V
over 300 V to 690 V inclusive 2500 V
over 690 V to 800 V inclusive 3000 V
over 800 V to 1000 V inclusive 3500 V
over 1000 V to 1500 V inclusive* 3500 V
Note: *For Direct-current (DC) only

TABLE 6
Clearance and Creepage Distance for Switchboards, Distribution Boards, Chargers,
Motor Control Centers and Controllers (1) [See 4-6-4/7.11.6]
Rated insulation voltage (V) Minimum clearances mm (in.) Minimum creepage distances mm (in.)
Up to 250 15 (19/32) 20 (25/32)
From 251 to 660 20 (25/32) 30 (13/16)
(2)
Above 660 25 (1) 35 (13/8)
Notes:
1 The values in this table apply to clearances and creepage distances between live parts as well as between live parts
and exposed conductive parts, including earthing.
2 For 1 kV to 15 kV systems, see 4-6-5/1.1.4.

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TABLE 7
Equipment and Instrumentation for Switchboard [See 4-6-4/7.15.4]
Instrumentation and
Equipment Alternating-current (AC) Switchboard Direct-current (DC) Switchboard
1. Pilot Lamp A pilot lamp for each generator connected between A pilot lamp for each generator connected between
generator and circuit breaker. See Note 3. generator and circuit breaker.
2. Generator A generator switch or disconnecting links in series with A generator switch, or disconnecting links, in series with
Disconnect the generator circuit breaker which is to disconnect the circuit breaker which will open positive, negative,
completely all leads of the generator and the circuit neutral and equalizer leads, except that for 3-wire
breaker from the buses, except the earth lead. (1) generators, equalizer poles may be provided on the
circuit breaker. For 3-wire generators, the circuit
breakers are to protect against a short circuit on the
equalizer buses. (1)
3. Field Rheostat A field rheostat for each generator and each exciter. (2) A field rheostat for each generator. (2).
4. Insulation A means for continuously monitoring the electrical A means for continuously monitoring the electrical
Monitor and insulation level to earth, and an audible or visual alarm insulation level to earth, and an audible or visual alarm
Alarm for abnormally low insulation values. (3) for abnormally low insulation values. For 3-wire
generators, see 4-6-5/5.3. (3)
5. Ammeter An ammeter for each generator with a selector switch to An ammeter for each 2-wire generator. For each 3-wire
read the current of each phase. (3) generator, an ammeter for each positive and negative
lead and a center-zero ammeter in the earth connection at
the generator switchboard. Ammeters are to be so
located in the circuit as to indicate total generator
current.
6. Voltmeter A voltmeter for each generator, with a selector switch to A voltmeter for each generator with voltmeter switch for
each phase of the generator and to one phase of the bus. (3) connecting the voltmeter to indicate generator voltage
and bus voltage. For each 3-wire generator, a voltmeter
with voltmeter switch for connecting the voltmeter to
indicate generator voltage, positive to negative, positive
to neutral, and neutral to negative. Where permanent
provisions for shore connections are fitted, one voltmeter
switch to provide also for reading shore-connection
voltage, positive to negative.
7. Space Heater Where electric heaters are provided for generators, a Where electric heaters are provided for generators, a
Pilot Lamp heater pilot lamp is to be fitted for each generator. heater pilot lamp is to be fitted for each generator.
8. Synchroscope A synchroscope or synchronizing lamps with selector Not applicable.
or Lamps switch for paralleling in any combination. See Note 3.
9. Prime mover Control for prime mover speed for paralleling. (3) Not applicable.
Speed Control
10. Wattmeter Where generators are arranged for parallel operation, an Not applicable.
indicating wattmeter is to be fitted for each generator. (3)
11. Frequency A frequency meter with selector switch to connect to any Not applicable.
Meter generator. (3)
12. Field Switch A double-pole field switch with discharge clips and Not applicable.
resistor for each generator. (2)
13. Voltage A voltage regulator. (3) Not applicable.
Regulator
14. Stator Winding For alternating current propulsion generator above 500 For direct current propulsion generator above 500 kW,
Temperature kW, a stator winding temperature indicator is to be fitted an interpole winding temperature indicator is to be fitted
Indicator for each generator control panel. (3,4) for each generator control panel. (3,4)
Notes:
1 The switch or links may be omitted when draw-out or plug-in mounted generator breakers are furnished.
2 For generators with variable voltage exciters or rotary amplifier exciters, each controlled by voltage-regulator unit acting
on the exciter field, the field switch, the discharge resistor and generator field rheostat may be omitted.
3 (2005) Where vessels have centralized control systems in accordance with Part 4, Chapter 7 and the generators can be
paralleled from the centralized control station, and the switchboard is located in the centralized control station, this
equipment may be mounted on the control console. See 4-6-4/7.15.4.
4 For high voltage systems, see also 4-6-5/1.11.1(c).

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TABLE 8
Temperature Rise for Transformers (1, 2)
Insulation Class Copper Temperature Rise by Resistance Hottest Spot Temperature Rise
Class A 55°C (99°F) 65°C (117°F)
Class B 80°C (144°F) 110°C (198°F)
Class F 115°C (207°F) 145°C (261°F)
Class H 150°C (270°F) 180°C (324°F)
Notes:
1 Metallic parts in contact with or adjacent to insulation are not to attain a temperature in excess of that allowed for
the hottest-spot copper temperature adjacent to that insulation.
2 Temperature rises are based on an ambient temperature of 40°C. See 4-6-4/9.3.

TABLE 9
Types of Cable Insulation [See 4-6-4/13.1.4]
Insulation Type Designation Insulation Materials Maximum Conductor Temperature
V60, PVC/A Polyvinyl Chloride – General purpose 60°C (140°F)*
V75, PVC Polyvinyl Chloride – Heat resisting 75°C (167°F) *
R85, XLPE Cross-linked Polyethylene 85°C (185°F) *
E85, EPR Ethylene Propylene Rubber 85°C (185°F) *
M95 Mineral (MI) 95°C (203°F)*
S95 Silicone Rubber 95°C (203°F) *

* A maximum conductor temperature of 250°C (482°F) is permissible for special applications and standard end fittings may be
used, provided the temperature does not exceed 85°C (185°F) at the end of fittings. However, when the temperature at the end of
the fittings is higher than 85°C (185°F), special consideration will be given to an appropriate end fitting.

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TABLE 10
Maximum Current Carrying Capacity for Insulated Copper
Wires and Cables [See 4-6-4/13.1.1]
Values in amperes
45°C (113°F) Ambient
750 V and Less (AC or DC)
Conductor Size 1/C TYPE 2/C TYPE 3-4/C TYPE
V75, V75, V75,
Heat R85, Heat R85, Heat R85,
V60 Resist. XLPE, M95, V60 Resist. XLPE, M95, V60 Resist. XLPE, M95,
103 PVC/A PVC E85, S95 PVC/A PVC E85, S95 PVC/A PVC E85, S95
circ 60°C 75°C 85°C 95°C 60°C 75°C 85°C 95°C 60°C 75°C 85°C 95°C
mm2 mils (140°F) (167°F) (185°F) (203°F) (140°F) (167°F) (185°F) (203°F) (140°F) (167°F) (185°F) (203°F)
625 755 894 1006 642 760 855 529 626 704
600 736 872 981 626 741 834 515 610 687
1000 662 784 882 563 666 750 463 549 617
500 656 778 875 558 661 744 459 545 613
950 641 760 854 545 646 726 449 532 598
900 620 734 826 527 624 702 434 514 578
850 598 709 797 508 603 677 419 496 558
800 576 682 767 490 580 652 403 477 540
400 571 677 761 485 575 647 400 474 533
750 553 655 737 470 557 626 387 459 516
700 529 628 706 450 534 600 370 440 494
650 506 599 674 430 509 573 354 419 472
600 481 570 641 409 485 545 337 399 449
300 335 477 565 636 285 405 480 541 235 334 396 445
550 455 540 607 387 459 516 319 378 425
500 429 509 572 365 433 486 300 356 400
240 290 415 492 553 247 353 418 470 203 291 344 387
450 402 476 536 342 405 456 281 333 375
400 373 442 498 317 376 423 261 309 349
185 250 353 418 470 213 300 355 400 175 247 293 329
350 343 407 458 292 346 389 240 285 321
300 312 370 416 265 315 354 218 259 291
150 220 309 367 412 187 263 312 350 154 216 257 288
250 278 330 371 236 281 315 195 231 260
120 190 269 319 359 162 229 271 305 133 188 223 251
212 251 297 335 213 252 285 176 208 235
95 165 232 276 310 140 197 235 264 116 162 193 217
168 217 257 289 184 218 246 152 180 202
70 135 192 228 256 115 163 194 218 95 134 160 179
133 188 222 250 160 189 213 132 155 175
106 163 193 217 139 164 184 114 135 152
50 105 156 184 208 89 133 156 177 74 109 129 146
83.7 140 166 187 119 141 159 98 116 131
35 87 125 148 166 74 106 126 141 61 88 104 116
66.4 121 144 162 103 122 138 85 101 113
52.6 105 124 140 89 105 119 74 87 98
25 71 101 120 135 60 86 102 115 50 71 84 95
41.7 91 108 121 77 92 103 64 76 85
33.1 79 93 105 67 79 89 55 65 74

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TABLE 10 (continued)
Maximum Current Carrying Capacity for Insulated Copper
Wires and Cables [See 4-6-4/13.1.1]
16 54 76 91 102 46 65 77 87 38 53 64 71
26.3 68 81 91 58 69 77 48 57 64
20.8 59 70 78 50 60 66 41 49 55
10 40 57 67 76 34 48 57 65 28 40 47 53
16.5 51 60 68 43 51 58 36 42 48
6 29 41 49 55 25 35 42 47 20 29 34 39
10.4 38 45 51 32 38 43 27 32 36
4 22 32 38 43 19 27 32 37 15 22 27 30
6.53 28 34 38 24 29 32 20 24 27
2.5 17 24 28 32 14 20 24 27 12 17 20 22
4.11 21 25 32 18 21 27 15 18 22
1.5 12 17 21 26 10 14 18 22 8 12 15 18
1.25 15 18 23 13 15 20 11 13 16
1.0 8 13 16 20 7 11 14 17 6 9 11 14

Notes:
1 The values given above have been calculated for an ambient of 45°C (113°F), and assume that a conductor temperature
equal to the maximum rated temperature of the insulation is reached and maintained continuously in the case of a
group of four cables bunched together and laid in free air.
2 The current rating values given in 4-6-4/Table 10 (and those derived therefrom) may be considered applicable, without
correction factors, for cables double-banked on cable trays, in cable conduits or cable pipes, except as noted in
Note 3.
3 For bunched cables, see 4-6-3/5.11.1.
4 These current ratings are applicable for both armored and unarmored cables.
5 If ambient temperature differs from 45°C (113°F), the values in 4-6-4/Table 10 are to be multiplied by the following
factors.

Maximum Conductor Ambient Correction Factor

Temperature 40°C (104°F) 50°C (122°F) 55°C (131°F) 60°C (140°F) 65°C (149°F) 70°C (158°F)
60°C (140°F) 1.15 0.82 — — — —
75°C (167°F) 1.08 0.91 0.82 0.71 0.58 —
80°C (176°F) 1.07 0.93 0.85 0.76 0.65 0.53
85°C (185°F) 1.06 0.94 0.87 0.79 0.71 0.61
95°C (203°F) 1.05 0.95 0.89 0.84 0.77 0.71

6 Where the number of conductors in a cable exceeds four, as in control cables, the maximum current carrying capacity
of each conductor is to be reduced as in the following table:

No. of Conductors % of 3–4/C TYPE Values in 4-6-4/Table 10

5–6 80
7–24 70
25–42 60
43 and above 50

7 When a mineral-insulated cable is installed in such a location that its copper sheath is liable to be touched when in
service, the current rating is to be multiplied by the correction factor 0.80 in order that the sheath temperature does
not exceed 70°C (158°F).
8 Cables being accepted based on approved alternate standard may have current carrying capacity of that standard,
provided the cables are in full compliance with that standard.

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TABLE 11
Additional Services Requiring Electrical Equipment to be Designed, Constructed and
Tested to the Requirements in Section 4-6-4
[See 4-6-4/1, 4-6-4/3.1.1, 4-6-4/3.3.1, 4-6-4/7.1.1 and 4-6-4/7.3.1] (2010)
(a) Equipment necessary for specific class notations (Such as refrigerated cargo notations, dynamic positioning
systems, etc.). See Note.
(b) Cargo Pump Motors (oil carriers, gas carriers, chemical carriers, liquefied gas carriers, etc.)
(c) Motors for hydraulic power unit for hydraulically driven cargo pump motors
(d) High duty gas compressors on liquefied gas carriers
Note: See 6-2-1/7 of the Steel Vessel Rules for refrigerated cargo notations and 4-3-5/15 of the Steel Vessel Rules for
dynamic positioning notations.

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PART Section 5: Specialized Installations

4
CHAPTER 6 Electrical Installations

SECTION 5 Specialized Installations

1 High Voltage Systems

1.1 General
1.1.1 Application (2003)
The following requirements in this Subsection are applicable to AC systems with nominal voltage
(phase to phase) exceeding 1 kV. Unless stated otherwise, high voltage equipment and systems are
to comply with the other parts in Part 4, Chapter 6 for low voltage equipment and systems, as well.
1.1.2 Standard Voltages (2003)
The nominal standard voltage is not to exceed 15 kV. A higher voltage may be considered for
special application.
1.1.3 Air Clearance and Creepage Distance
1.1.3(a) Air clearance (2003). Phase-to-phase air clearances and phase-to-earth air clearances
between non-insulated parts are to be not less than the minimum as specified below.
Nominal Voltage Minimum air
in kV clearance in mm (in.)
3–3.3 55 (2.2)
6–6.6 90 (3.6)
10–11 120 (4.8)
15 160 (6.3)

Where intermediate values of nominal voltages are accepted, the next higher air clearance is to be
observed. In the case of smaller distances, an appropriate voltage impulse test is to be applied.
1.1.3(b) Creepage distance. Creepage distances between live parts and between live parts and
earthed metal parts are to be adequate for the nominal voltage of the system, due regard being paid
to the comparative tracking index of insulating materials under moist conditions, according to the
IEC Publication 60112, and to the transient over-voltage developed by switching and fault conditions.

1.3 System Design

1.3.1 Selective Coordination
Selective coordination is to be in accordance with 4-6-2/9.1.5, regardless of the system neutral
earthing arrangement.
1.3.2 Earthed Neutral Systems
1.3.2(a) Neutral earthing (2003). The current in the earth fault condition is to be not in excess of
full load current of the largest generator on the switchboard or relevant switchboard section and in
no case less than three times the minimum current required for operation of any device in the earth
fault condition.
At least one source neutral to ground connection is to be available whenever the system is in the
energized mode.

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1.3.2(b) Equipment (2003). Electrical equipment in directly earthed neutral or other neutral earthed
systems is to be able to withstand the current due to a single phase fault against earth for a period
necessary to trip the protection device.
1.3.3 Neutral Disconnection
Each generator neutral is to be provided with means for disconnection.
1.3.4 Hull Connection of Earthing Impedance (2003)
All earthing impedances are to be connected to the hull. The connection to the hull is to be so
arranged that any circulating currents in the earth connections will not interfere with radio, radar,
communication and control equipment circuits. In systems with neutral earthed, connection of the
neutral to the hull is to be provided for each generator switchboard section.
1.3.5 Earth Fault Detection (2003)
An earth fault is to be indicated by visual and audible means. In low impedance or direct earthed
systems, provision is to be made to disconnect automatically the faulty circuits. In high impedance
earthed systems where outgoing feeders will not be isolated in case of an earth fault, the insulation
of the equipment is to be designed for the phase to phase voltage.
1.3.6 Number and Capacity of Transformers (2002)
The number and capacity of transformers is to be sufficient, under seagoing conditions, with any
three-phase transformer or any one transformer of three single phase transformer bank out of service
to carry those electrical loads for essential service and for minimum comfortable conditions of
habitability. For this purpose and for the purpose of immediate continuity of supply, the provision
of a single-phase transformer carried onboard as a spare for a three phase transformer bank or V-V
connection by two remaining single-phase transformers is not acceptable.

1.5 Circuit Breakers and Switches – Auxiliary Circuit Power Supply Systems (2004)
1.5.1 Source and Capacity of Power Supply
Where electrical energy or mechanical energy is required for the operation of circuit breakers and
switches, a means of storing such energy is to be provided with a capacity at least sufficient for
two on/off operation cycles of all of the components. However, the tripping due to overload or
short-circuit, and under-voltage is to be independent of any stored electrical energy sources. This
does not preclude the use of stored energy for shunt tripping, provided alarms are activated upon
loss of continuity in the release circuits and power supply failures. The stored energy may be
supplied from within the circuit in which the circuit breakers or switches are located.
1.5.2 Number of External Sources of Stored Energy
Where the stored energy is supplied from a source external to the circuit, such supply is to be from
at least two sources so arranged that a failure or loss of one source will not cause the loss of more
than one set of generators and/or essential services. Where it will be necessary to have the source
of supply available for dead ship startup, the source of supply is to be provided from the emergency
source of electrical power

1.7 Circuit Protection

1.7.1 Protection of Generator (2003)
Protection against phase-to-phase fault in the cables connecting the generators to the switchboard
and against inter-winding faults within the generator is to be provided. This is to trip the generator
circuit breaker and automatically de-excite the generator. In distribution systems with a low impedance
earthed neutral, phase to earth faults are to be likewise treated.
1.7.2 Protection of Power Transformers (2003)
Power transformers are to be provided with overload and short circuit protection. Each high-voltage
transformer intended to supply power to the low-voltage ship service switchboard is to be protected
in accordance with 4-6-2/9.15. In addition, the following means for protecting the transformers or
the electric distribution system are to be provided:

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1.7.2(a) Coordinated trips of protective devices (2002). Discriminative tripping is to be provided

for the following. See 4-6-2/9.1.5.
i) Between the primary side protective device of the transformer and the feeder protective
devices on the low-voltage ship service switchboard, or
ii) Between the secondary side protective device of the transformer, if fitted, and the feeder
protective devices on the low-voltage ship service switchboard.
1.7.2(b) Load shedding arrangement (2002). Where the power is supplied through a single set of
three-phase transformers to a low-voltage ship service switchboard, automatic load shedding
arrangements are to be provided when the total load connected to the low voltage ship service
switchboard exceeds the rated capacity of the transformer. See 4-6-2/1.7 and 4-6-2/9.3.3.
1.7.2(c) Protection from electrical disturbance (2002). Means or arrangements are to be provided
for protecting the transformers from voltage transients generated within the system due to circuit
conditions, such as high-frequency current interruption and current suppression (chopping) as the
result of switching, vacuum cartridge circuit breaker operation or thyrister-switching.
An analysis or data for the estimated voltage transients is to be submitted to show that the insulation
of the transformer is capable of withstanding the estimated voltage transients. See 4-6-5/1.11.3(b).
1.7.2(d) Detection of phase-to-phase internal faults (2002). For three-phase transformers of 100 kVA
or more, means for detecting a phase-to-phase internal fault are to be provided. The detection of the
phase-to-phase internal fault is to activate an alarm at the manned control station or to automatically
disconnect the transformer from the high-voltage power distribution network.
1.7.2(e) Protection from earth faults (2002). Where a Y-neutral of three-phase transformer windings
is earthed, means for detecting an earth fault are to be provided. The detection of the earth fault is
to activate an alarm at the manned control station or to automatically disconnect the transformer
from the high-voltage power distribution network.
1.7.2(f) Transformers arranged in parallel (2002). When transformers are connected in parallel,
tripping of the protective devices at the primary side is to automatically trip the switch or protective
devices connected at the secondary side.
1.7.3 Voltage Transformers for Control and Instrumentation (2003)
Voltage transformers are to be provided with overload and short circuit protection on the secondary
side.
1.7.4 Fuses (2003)
Fuses are not to be used for overload protection.
1.7.5 Over Voltage Protection (2003)
Lower voltage systems supplied through transformers from high voltage systems are to be protected
against overvoltages. This may be achieved by:
i) Direct earthing of the lower voltage system,
ii) Appropriate neutral voltage limiters, or
iii) Earthed screen between primary and secondary winding of transformers

1.9 Equipment Installation and Arrangement

1.9.1 Degree of Protection
The degree of equipment protection is to be in accordance with 4-6-3/Table 1.
1.9.2 Protective Arrangements
1.9.2(a) Interlocking Arrangements. Where high-voltage equipment is not contained in an enclosure
but a room forms the enclosure of the equipment, the access doors are to be so interlocked that
they cannot be opened until the supply is isolated and the equipment earthed down.

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1.9.2(b) Warning Plate. At the entrance of such spaces, a suitable marking is to be placed which
indicates danger of high-voltage and the maximum voltage inside the space. For high-voltage
electrical equipment installed outside these spaces, a similar marking is to be provided.
1.9.3 Cables
1.9.3(a) Runs of Cables (2003). In accommodation spaces, high voltage cables are to be run in
enclosed cable transit systems.
1.9.3(b) Segregation (2003). High voltage cables of different voltage ratings are not to be installed
in the same cable bunch, duct, pipe or box. Where high voltage cables of different voltage ratings
are installed on the same cable tray, the air clearance between cables is not to be less than the
minimum air clearance for the higher voltage side in 4-6-5/1.1.3(a). However, high voltage cables
are not to be installed on the same cable tray for the cables operating at the nominal system voltage
of 1 kV or less.
Higher voltage equipment is not to be combined with lower voltage equipment in the same
enclosure, unless segregation or other suitable measures are taken to ensure safe access to lower
voltage equipment
1.9.3(c) Installation Arrangements (2003). High voltage cables are to be installed on cable trays
or equivalent when they are provided with a continuous metallic sheath or armor which is effectively
bonded to earth. Otherwise, they are to be installed for their entire length in metallic casings
effectively bonded to earth.
1.9.3(d) Termination and Splices (2003). Terminations in all conductors of high voltage cables
are to be, as far as practicable, effectively covered with suitable insulating material. In terminal boxes,
if conductors are not insulated, phases are to be separated from earth and from each other by
substantial barriers of suitable insulating materials. High voltage cables of the radial field type
(i.e., having a conductive layer to control the electric field within the insulation) are to have
terminations which provide electric stress control.
Terminations are to be of a type compatible with the insulation and jacket material of the cable
and are to be provided with means to ground all metallic shielding components (i.e., tapes, wires, etc).
1.9.3(e) Marking. High voltage cables are to be readily identifiable by suitable marking.
1.9.3(f) Test after Installation (2003). A voltage withstand test is to be carried out on each completed
cable and its accessories before a new high voltage installation, including additions to an existing
installation, is put into service.
The test is to be carried out after an insulation resistance test.
When a DC voltage withstand test is carried out, the voltage is to be not less than:
1.6(2.5Uo + 2 kV) for cables of rated voltage (Uo) up to and including 3.6 kV, or
4.2Uo for higher rated voltages
where Uo is the rated power frequency voltage between conductor and earth or metallic screen, for
which the cable is designed.
The test voltage is to be maintained for a minimum of 15 minutes.
After completion of the test, the conductors are to be connected to earth for a sufficient period in
order to remove any trapped electric charge.
An insulation resistance test is then repeated.
Alternatively, an AC voltage withstand test may be carried out upon advice from the high voltage
cable manufacturer at a voltage not less than the normal operating voltage of the cable, and it is to
be maintained for a minimum of 24 hours.
Note: Tests in accordance with IEC Publication 60502 will also be considered adequate.

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1.11 Machinery and Equipment

1.11.1 Rotating Machines
1.11.1(a) Protection. Rotating machines are to have a degree of protection of at least IP23; for
terminal box, IP44; and for motors accessible to unqualified personnel, IP43.
1.11.1(b) Windings (2003). Generator stator windings are to have all phase ends brought out for
the installation of the differential protection.
1.11.1(c) Temperature detectors. Rotating machines are to be provided with temperature detectors
in their stator windings to actuate a visual and audible alarm in a normally attended position whenever
the temperature exceeds the permissible limit. If embedded temperature detectors are used, means
are to be provided to protect the circuit against over-voltage.
1.11.1(d) Cooler (2004). No text.
1.11.1(e) Space heater. Effective means are to be provided to prevent the accumulation of moisture
and condensation within the machines when they are idle.
1.11.1(f) Tests (2003). In addition to the tests normally required for rotating machinery, a high
frequency, high voltage test, in accordance with IEC Publication 60034-15, is to be carried out on
the individual coils in order to demonstrate a satisfactory withstand level of the inter-turn insulation
to steep fronted switching surges.
1.11.2 Switchgear and Control-gear Assemblies
Switchgear and control gear assemblies are to be constructed according to the IEC Publication
60298 and the following additional requirements:
1.11.2(a) Protection (2003). Switchgear, control-gear assemblies and static converters are to
have a degree of protection of at least IP32. For those installed in a space accessible to unqualified
personnel, the protection is to be increased to IP4X, where “X” is dependent on the liquid condition
in the location in which the equipment is to be installed (see 4-6-1/Table 3).
1.11.2(b) Mechanical construction (2003). Switchgear is to be of metal-enclosed type in accordance
with IEC Publication 60298 or of the insulation-enclosed type in accordance with IEC Publication
60466.
1.11.2(c) Configuration (2003). The main bus bars are to be subdivided into at least two independent
parts which are to be connected by at least one circuit breaker or other approved means, each part
being supplied by at least one generator. The connection of generating sets and any other required
duplicated equipment is to be divided, as far as possible, equally between the parts.
1.11.2(d) Clearance and creepage distances. For clearance and creepage distances, see 4-6-5/1.1.3.
1.11.2(e) Locking facilities. Withdrawable circuit breakers and switches are to be provided with
mechanical locking facilities in both service and disconnected positions. For maintenance purposes,
key locking of withdrawable circuit breakers, switches and fixed disconnectors is to be possible.
Withdrawable circuit breakers, when in the service position, are to have no relative motion between
fixed and moving parts.
1.11.2(f) Shutters. The fixed contacts of withdrawable circuit breakers and switches are to be so
arranged that in the withdrawn position, the live contacts of the bus bars are automatically covered.
1.11.2(g) Earthing and short-circuiting facilities (2003). For maintenance purposes, an adequate
number of earthing and short circuiting facilities are to be provided to enable equipment and cables
to be earthed or short-circuited to earth before being worked upon.
1.11.2(h) Tests (2003). A power frequency voltage test is to be carried out on high voltage switchgear
and control-gear assemblies. The test procedure and voltages are to be in accordance with IEC
Publication 60298.

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1.11.3 Transformers (2002)

1.11.3(a) Application (2008). Provisions of 4-6-5/1.11.3 are applicable to power transformers for
essential services. See also 4-6-4/9. Items 4-6-5/1.11.3(c) and 4-6-5/1.11.3(d) are applicable to
transformers of the dry type only. These requirements are not applicable to transformers intended
for the following services:
• Instrument transformers.
• Transformers for static converters.
• Starting transformers.
Dry type transformers are to comply with the applicable parts of the IEC 60076 Series. Liquid-
filled transformers are to comply with the applicable parts of the IEC 60076 Series. Oil-immersed
transformers are to be provided with the following alarms and protections:
• Liquid level (Low) – alarm
• Liquid temperature (High) – alarm
• Liquid level (Low) – trip or load reduction
• Liquid temperature (High) – trip or load reduction
• Gas pressure relay (High) – trip
1.11.3(b) Plans (2002). In addition to the details required in 4-6-4/9, the applicable standard of
construction and the rated withstanding voltage of the insulation are also to be submitted for review.
1.11.3(c) Enclosure (2003). Transformers are to have a degree of protection in accordance with
4-6-1/Table 2, but not less than IP23. However, when installed in spaces accessible to unqualified
personnel, the degree of protection is to be increased to IP44. For transformers not contained in
enclosures, see 4-6-5/1.9.1.
1.11.3(d) Space heater. Effective means to prevent accumulation of moisture and condensation
within the transformers (when de-energized) is to be provided.
1.11.3(e) Testing (2002). Three-phase transformers or three-phase bank transformers of 100 kVA
and above are to be tested in the presence of the Surveyor. The test items are to be in accordance
with the standard applicable to the transformer. The tests are also to be carried out in the presence
of the Surveyor for each individual transformer. Transformers of less than 100 kVA will be accepted
subject to a satisfactory performance test conducted to the satisfaction of the Surveyor after installation.
Specific requirements are applicable for the following tests:
i) In the dielectric strength test, the short duration power frequency withstand voltage to be
applied is to follow the standard applicable to the transformer but not less than the estimated
voltage transient generated within the system. If the short duration power frequency withstand
voltage is not specified in the applicable standard, IEC 60076-3 is to be referred to. For
the voltage transient, see 4-6-5/1.7.2(c).
ii) The induced over-voltage withstand test (layer test) is also to be carried out in accordance
with the standard applicable to the transformers in the presence of the Surveyor. This test
is intended to verify the power-frequency withstand strength along the winding under test
and between its phase (strength between turns and between layers in the windings). If the
induced over-voltage withstand test is not specified in the applicable standard, IEC
60076-3 is to be referred to.
1.11.3(f) Nameplate (2002). In addition to the requirements in 4-6-4/Table 4c, the following
information is also to be indicated on the nameplate:
• Applicable standard
• Short duration power frequency withstand voltage for verification of insulation level of each
winding

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1.11.4 Cables (2003)

1.11.4(a) Standards. Cables are to be constructed to IEC Publication 60092-353, 60092-354 or
other equivalent recognized standard. See also 4-6-4/13.1.

3 Electric Propulsion System

3.1 General (2007)

3.1.1 Application
The following requirements in this subsection are applicable to electric propulsion systems. Electric
propulsion systems complying with other recognized standards will be considered. Unless stated
otherwise, electric propulsion equipment and systems are to comply with the applicable requirements
in other parts of Part 4, Chapter 6, as well.
3.1.2 Plans and Data to be Submitted
In addition to the plans and data to be submitted in accordance with 4-6-2/1, 4-6-3/1 and 4-6-4/1,
the following plans and data are to be submitted for review.
• One-line diagrams of the propulsion control system for power supply, circuit protection, alarm,
monitoring, safety and emergency shutdown systems, including list of alarm and monitoring
points.
• Plans showing the location of the propulsion controls and its monitoring stations.
• Arrangements and details of the propulsion control console or panel, including schematic diagram
of the system therein.
• Arrangements and details of electric coupling.
• Arrangements and details of the semiconductor converters enclosure for the propulsion system,
including data for the semiconductor converter and cooling system with its interlocking
arrangement.

3.3 System Design (2007)

3.3.1 General
For the purposes of the electric propulsion system requirements, an integrated electric propulsion
system is a system where a common set of generators supply power to the vessel service loads as
well as the propulsion loads.
3.3.2 Generating Capacity
For vessels with an integrated electric propulsion system, under normal sea-going conditions, when
one generator is out of service, the remaining generator capacity is to be sufficient to carry all of
the vessel services (essential services, normal services and for minimum comfortable conditions of
habitability) and an effective level of propulsion.
3.3.3 Power Management System
For vessels with an integrated electric propulsion system, a power management system is to be
provided. The power management system is to control load sharing between generators, prevent
blackouts, maintain power to the essential service loads and maintain power to the propulsion loads.
The system is to account for the following operating scenarios.
• All generators in operation, then the loss of one generator
• When at least one generator is not in operation and there is an increase in the propulsion loads
or a loss of one of the generators, that would result in the need to start a generator that was not
in operation.

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Further, the system is to prevent overloading the generators, by reducing the propulsion load or
load shedding of non essential loads. In general, the system is to limit power to the propulsion
loads to maintain power to the vessel’s essential service loads. However, the system is to shed
non essential loads to maintain power to the propulsion loads.
An audible and visible alarm is to be installed at each propulsion control location and is to be
activated when the system is limiting the propulsion power in order to maintain power to the other
essential service loads.
When at least one generator is not in operation, consideration should be given to keeping one
generator in stand by mode, so that it can be brought on line within 45 seconds, upon failure of
one of the running generators.
Operation with only one generator on line should only be considered, when another generator can
be brought on line within 45 seconds of failure of the running generator.
3.3.4 Regenerative Power
For systems where regenerative power may be developed through the semiconductor converters,
the regenerative power is not to cause disturbances in the system voltage and frequency which
exceeds the limits of 4-6-1/9. See also 4-6-5/3.17.4(a) and 4-6-5/3.17.4(e).
3.3.5 Harmonics
A harmonic distortion calculation is to be submitted for review for all vessels with electric propulsion.
The calculation is to indicate that the harmonic distortion levels at all locations throughout the
power distribution system (main generation switchboard, downstream power distribution switchboards,
etc.) are within the limits of 4-6-2/7.9. The harmonic distortion levels at dedicated propulsion
buses are also to be within the limits of 4-6-2/7.9, otherwise documentation from the manufacturer
is to be submitted indicating that the equipment is designed for operation at a higher level of distortion.

3.5 Propulsion Power Supply Systems

3.5.1 Propulsion Generators
3.5.1(a) Power Supply. The power for the propulsion equipment may be derived from a single
generator. If a ship service generator is also used for propulsion purposes other than for boosting
the propulsion power, such generator and power supply circuits to propulsion systems are also to
comply with the applicable requirements in this subsection. See also 4-6-2/3.1.4.
3.5.1(b) Single System. If a propulsion system contains only one generator and one motor and
cannot be connected to another propulsion system, more than one exciter set is to be provided for
each machine. However, this is not necessary for self-excited generators or for multi-propeller
propulsion vessels where any additional exciter set may be common for the vessel.
3.5.1(c) Multiple Systems. Systems having two or more propulsion generators, two or more
semiconductor converters or two or more motors on one propeller shaft are to be so arranged that
any unit may be taken out of service and disconnected electrically without preventing the operation
of the remaining units.
3.5.1(d) Excitation Systems. Arrangements for electric propulsion generators are to be such that
propulsion can be maintained in case of failure of an excitation system or failure of a power supply
for an excitation system. Propulsion may be at reduced power under such conditions where two or
more propulsion generators are installed, provided such reduced power is sufficient to provide for
a speed of not less than 7 knots or 1/2 of design speed, whichever is the lesser.
3.5.1(e) Features for Other Services. If the propulsion generator is used for other purposes than
for propulsion, such as dredging, cargo oil pumps and other special services, overload protection
in the auxiliary circuit and means for making voltage adjustments are to be provided at the control
board. When propulsion alternating-current generators are used for other services for operation in
port, the port excitation control is to be provided with a device that is to operate just below normal
idling speed of the generator to remove excitation automatically.

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3.5.2 Propulsion Excitation

3.5.2(a) Excitation Circuits. Every exciter set is to be supplied by a separate feeder. Excitation
circuits are not to be fitted with overload circuit-interrupting devices, except those intended to
function in connection with the protection for the propulsion generator. In such cases, the field
circuit breaker is to be provided with a discharge resistor, unless a permanent discharge resistor is
provided.
3.5.2(b) Field Circuits. Field circuits are to be provided with means for suppressing voltage rise
when a field switch is opened. Where fuses are used for excitation circuit protection, it is essential
that they do not interrupt the field discharge resistor circuit upon rupturing.
3.5.2(c) Ship’s Service Generator Connection. Where the excitation supply is obtained from the
ship’s service generators, the connection is to be made to the generator side of the generator circuit
breaker with the excitation supply passing through the overload current device of the breaker.
3.5.3 Semiconductor Converters (1999)
3.5.3(a) Semiconductor converter circuits are to be able to withstand the transient overcurrents to
which the system is subject during maneuvering.
3.5.3(b) Where semiconductor converters are connected in parallel, the current for each
semiconductor converter is to be equally distributed as far as practicable. If several elements are
connected in parallel and a separate fan is fitted for each parallel branch, arrangements are to be
made for disconnecting the circuit for which ventilation is not available.
3.5.3(c) Where semiconductor converters are connected in series, the voltage between the
semiconductor devices are to be equally distributed as far as practicable.
3.5.3(d) In case of failure of the cooling system, an alarm is to be given or the current is to be
reduced automatically.

3.7 Circuit Protection

3.7.1 Setting
Overcurrent protective devices, if any, in the main circuits are to be set sufficiently high so as not
to operate on overcurrents caused by maneuvering or normal operation in heavy seas or in floating
broken ice.
3.7.2 Direct-current (DC) Propulsion Circuits
3.7.2(a) Circuit Protection. Direct-current propulsion circuits are not to have fuses. Each circuit
is to be protected by overload relays to open the field circuits or by remote-controlled main-circuit
interrupting devices. Provision is to be made for closing circuit breakers promptly after opening.
3.7.2(b) Protection for Reversal of the Rotation. Where separately driven DC generators are
connected electrically in series, means shall be provided to prevent reversal of the rotation of a
generator upon failure of the driving power of its prime mover.
3.7.3 Excitation Circuits
An overload protection is not to be provided for opening of the excitation circuit.
3.7.4 Reduction of Magnetic Fluxes
Means are to be provided for selective tripping or rapid reduction of the magnetic fluxes of the
generators and motors so that overcurrents do not reach values which may endanger the plant.
3.7.5 Semiconductor Converters
3.7.5(a) Overvoltage Protection. Means are to be provided to prevent excessive overvoltages in
a supply system to which converters are connected. Visual and audible alarms are to be provided
at the control station for tripping of the protective fuses for these devices.
3.7.5(b) Overcurrent Protection. Arrangements are to be made so that the permissible current of
semiconductor elements cannot be exceeded during normal operation.

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3.7.5(c) Short-circuit Protection. Fuses are to be provided for protection of short-circuit of

semiconductor converters. Visual and audible alarms are to be provided at the control station for
tripping of these semiconductor protective fuses. In case of blown fuse, the respective part of the
plant is to be taken out of operation.
3.7.5(d) Filter Circuits. Fuses are to be provided for filter circuits. Visual and audible alarm are
to be provided at the control station for tripping of the fuse.
3.7.6 Direct-current (DC) Propulsion Motors Supplied by Semiconductor Converters (2008)
The protection features of the semiconductor converters are to be arranged to avoid a damaging
flashover in the DC propulsion motor. A possible cause of a damaging flashover would be removal
of the field current. The protection features of the semiconductor converters are to take into
account the increase in armature current created by the removal of the field current, due to
accidental loss of the field, or activation of a protection feature intended to protect the field.
To verify compliance with the above, the maximum time-current characteristics that can be
commutated by the motor as well as the time-current characteristics of the protective features of
the semiconductor converters are to be submitted for review. To avoid a damaging flashover, the
maximum time-current characteristics of the motor is to be provided by the motor manufacturer
and is to be used by the semiconductor converter manufacturer to determine the appropriate set
points for the protection features of the semiconductor converters.

3.9 Protection for Earth Leakage

3.9.1 Main Propulsion Circuits
Means for earth leakage detection are to be provided for the main propulsion circuit and be arranged
to operate an alarm upon the occurrence of an earth fault. When the fault current flowing is liable
to cause damage, arrangements for opening the main propulsion circuit are also to be provided.
3.9.2 Excitation Circuits
Means are to be provided for earth leakage detection in excitation circuits of propulsion machines
but may be omitted in circuits of brushless excitation systems and of machines rated up to 500 kW.
3.9.3 Alternating current (AC) Systems
Alternating current propulsion circuits are to be provided with an earthing detector alarm or indicator.
If the neutral is earthed for this purpose, it is to be through an arrangement which will limit the
current at full-rated voltage so that it will not exceed approximately 20 amperes upon a fault to
earth in the propulsion system. An unbalance relay is to be provided which is to open the generator
and motorfield circuits upon the occurrence of an appreciable unbalanced fault.
3.9.4 Direct-current (DC) Systems
The earthing detector may consist of a voltmeter or lights. Provision is to be made for protection
against severe overloads, excessive currents and electrical faults likely to result in damage to the
plant. Protective equipment is to be capable of being so set as not to operate on the overloads or
overcurrents experienced in a heavy seaway or when maneuvering.

3.11 Electric Propulsion Control

3.11.1 General
Failure of a control signal is not to cause an excessive increase in propeller speed. The reference
value transmitters in the control stations and the control equipment are to be so designed that any
defect in the desired value transmitters or in the cables between the control station and the propulsion
system will not cause a substantial increase in the propeller speed.
3.11.2 Automatic and Remote Control Systems
Where two or more control stations are provided outside of the engine room, or where automatic
control of the propulsion machinery is provided, Sections 4-7-1 through 4-7-5, as applicable, are
to be complied with. See 4-7-1/3 for propulsion class symbols.

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3.11.3 Testing and Inspection

Controls for electric propulsion equipment are to be inspected when finished and dielectric strength
tests and insulation resistance measurements made on the various circuits in the presence of the
Surveyor, preferably at the plant of manufacture. The satisfactory tripping and operation of all
relays, contactors and the various safety devices are also to be demonstrated.
3.11.4 Initiation of Control
The control of the propulsion system can be activated only when the delegated control lever is in
zero position and the system is ready for operation.
3.11.5 Emergency Stop
Each control station shall have an emergency stop device which is independent of the control lever.
3.11.6 Prime Mover Control
Where required by the system of control, means are to be provided at the control assembly for
controlling the prime mover speed and for mechanically tripping the throttle valve.
3.11.7 Control Power Failure
If failure of the power supply occurs in systems with power-aided control (e.g., with electric,
pneumatic or hydraulic aid), it is to be possible to restore control in a short time.
3.11.8 Protection
Arrangements are to be made so that opening of the control system assemblies or compartments
will not cause inadvertent or automatic loss of propulsion. Where oil gauges are mounted on the
main-control assembly, provision is to be made so that the oil will not come in contact with the
energized parts in case of leakage.
3.11.9 Interlocks
All levers for operating contactors, line switches, field switches and similar devices are to be
interlocked to prevent their improper operation. Interlocks are to be provided with the field lever
to prevent the opening of any main circuit without first reducing the field excitation to zero, except
that when the generators simultaneously supply power to an auxiliary load apart from the propulsion,
the field excitation need only be reduced to a low value.

3.13 Instrumentation at the Control Station

3.13.1 Indication, Display and Alarms
The necessary instruments to indicate existing conditions at all times are to be provided and mounted
on the control panel convenient to the operating levers and switches. Instruments and other devices
mounted on the switchboard are to be labeled and the instruments provided with a distinguishing
mark to indicate full-load conditions. Metallic cases of all permanently installed instruments are to
be permanently earthed. The following instruments, where applicable, are to be provided.
3.13.1(a) For AC Systems. Ammeter, voltmeter, indicating wattmeter and field ammeter (*) for
each propulsion generator and for each synchronous motor. See also 4-7-4/Table 6.
3.13.1(b) For DC Systems. An ammeter for each main circuit and one or more voltmeters with
selector switches for reading voltage on each propulsion generator and motor. See also 4-7-4/Table 6.
3.13.1(c) For Electric Slip Couplings. An ammeter for the coupling excitation circuit.
* Field ammeter is not required for brushless generators

3.13.2 Indication of Propulsion System Status

The control stations of the propulsion systems are to have at least the following indications for
each propeller.
3.13.2(a) “Ready for Operation”. Power circuits and necessary auxiliaries are in operation.
3.13.2(b) “Faulty”. Propeller is not controllable.
3.13.2(c) “Power Limitation”. In case of disturbance, for example, in the ventilators for propulsion
motors, in the converters, cooling water supply or load limitation of the generators.

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3.15 Equipment Installation and Arrangement

3.15.1 General
The arrangement of bus bars and wiring on the back of propulsion-control assemblies is to be such
that all parts, including the connections, are accessible. All nuts and connections are to be fitted
with locking devices to prevent loosening due to vibration. Clearance and creepage distance are to
be provided between parts of opposite polarity and between live parts and earth to prevent arcing.
See 4-6-1/19, 4-6-4/7.11.6 and 4-6-5/1.11.2(d).
3.15.2 Accessibility and Facilities for Repairs
3.15.2(a) Accessibility. For purposes of inspection and repair, provision is to be made for access
to the stator and rotor coils, and for the withdrawal and replacement of field coils. Adequate access is
to be provided to permit resurfacing of commutators and slip-rings, as well as the renewal and
bedding of brushes.
3.15.2(b) Facility for Supporting. Facilities shall be provided for supporting the shaft to permit
inspection and withdrawal of bearings.
3.15.2(c) Slip-couplings. Slip-couplings are to be designed to permit removal as a unit without
axial displacement of the driving and driven shaft, and without removing the poles.
3.15.3 Semiconductor Converters (1999)
Converters are to be installed away from sources of radiant energy in locations where the circulation
of air is not restricted to and from the converter and where the temperature of the inlet air to air-
cooled converters will not exceed that for which the converter is designed. Immersed-type converters
are to use a nonflammable liquid. Converter stacks are to have a protection of at least IP22 for
installations 1 kV or less and IP23 for installations above 1 kV, and mounted in such a manner
that they may be removed without dismantling the complete unit.
3.15.4 Propulsion Cables
Propulsion cables are not to have splices or joints, except terminal joints, and all cable terminals
are to be sealed against the admission of moisture or air. Similar precautions are to be taken during
installation by sealing all cable ends until the terminals are permanently attached. Cable supports
are to be designed to withstand short-circuited conditions. They are to be spaced less than 915 mm
(36 in.) apart and are to be arranged to prevent chafing of the cable. See 4-6-3/5.9.1.

3.17 Machinery and Equipment

3.17.1 Material Tests
The following materials intended for main propulsion installation are to be tested in accordance
with the ABS Rules for Materials and Welding (Part 2): thrust shafts, line shafts, propeller shafts,
shafting for propulsion generators and motors, coupling bolts, and in the case of direct-connected
turbine-driven propulsion generators, fan shrouds, centering and retaining rings. Major castings or
built-up parts such as frames, spiders and end shields are to be surface inspected and the welding
is to be in accordance with the ABS Rules for Materials and Welding (Part 2).
3.17.2 Temperature Rating
When generators, motors or slip-couplings for electric propulsion are fitted with an integral fan
and will be operated at speeds below the rated speed with full-load torque, full-load current or
full-load excitation temperature rise limits according to 4-6-4/Table 3 are not to be exceeded.
3.17.3 Protection Against Moisture Condensation
4-6-4/3.13.7 is applicable for rotating machines and converters, regardless of the weight of the
machines.

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3.17.4 Prime Movers

3.17.4(a) Capability. The prime mover rated output is to have adequate overloading and build-up
capacity for supplying the power which is necessary during transitional changes in operating conditions
of the electrical equipment. When maneuvering from full propeller speed ahead to full propeller
speed astern with the vessel making full way ahead, the prime mover is be capable of absorbing a
proportion of the regenerated power without tripping due to overspeed.
3.17.4(b) Speed Control. Prime movers of any type are to be provided with a governor capable of
maintaining the preset steady speed within a range not exceeding 5% of the rated full-load speed for
load changes from full-load to no-load.
3.17.4(c) Manual Controls. Where the speed control of the propeller requires speed variation of
the prime mover, the governor is to be provided with means for local manual control, as well as
for remote control. For turbines driving AC propulsion generators, where required by the system of
control, the governor is to be provided with means for local hand control, as well as remote adjustment
from the control station.
3.17.4(d) Parallel Operation. In case of parallel operation of generators, the governing system is
to permit stable operation to be maintained over the entire operational speed range of the prime movers.
3.17.4(e) Protection for Regenerated Power. Braking resistors or ballast consumers are to be
provided to absorb excess amounts of regenerated energy and to reduce the speed of rotation of
the propulsion motor. These braking resistors or ballast consumers are to be located external to the
mechanical and electric rotating machines. Alternatively, the amount of regenerated power may be
limited by the action of the control system.
3.17.5 Rotating Machines for Propulsion
The following requirements are applicable to propulsion generators and propulsion motors.
3.17.5(a) Ventilation and Protection. Electric rotating machines for propulsion are to be enclosed
ventilated or be provided with substantial wire or mesh screen to prevent personnel injury or entrance
of foreign matter. Dampers are to be provided in ventilating air ducts, except when re-circulating
systems are used.
3.17.5(b) Fire-extinguishing Systems. Electric rotating machines for propulsion which are enclosed
or in which the air gap is not directly exposed are to be fitted with fire-extinguishing systems suitable
for fires in electrical equipment. This will not be required where it can be established that the
machinery and insulation is self-extinguishing.
3.17.5(c) Air Coolers (2004). Air cooling systems for propulsion generators are to be in accordance
with 4-2-1/11.3 and 4-2-1/11.7. Water-air heat exchangers of rotating propulsion machines for
single systems (single generator and single motor), as specified in 4-6-5/3.5.1(b), are to have double
wall tubes and be fitted with a leak detector feature to monitor for any water leakage. A visual and
audible alarm is to be provided at a normally manned location to indicate such water leakage.
3.17.5(d) Temperature Sensors (1997). Stator windings of AC machines and interpole windings
of DC machines rated above 500 kW are to be provided with temperature sensors. See 4-7-4/Table 6.
3.17.6 Propulsion Generators
Excitation current for propulsion generators may be derived from attached rotating exciters, static
exciters, excitation motor-generator sets or special purpose generating units. Power for these exciters
may be derived from the machine being excited or from any ship service, emergency or special purpose
generating units.
3.17.7 Direct-current (DC) Propulsion Motors
3.17.7(a) Rotors. The rotors of DC propulsion motors are to be capable of withstanding overspeeding
up to the limit reached in accordance with the characteristics of the overspeed protection device at
its normal operational setting.
3.17.7(b) Overspeed Protection. An overspeed protection device is to be provided to prevent
excessive overspeeding of the propulsion motors due to light loads, loss of propeller, etc.

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3.17.8 Electric Couplings

3.17.8(a) General. Couplings are to be enclosed ventilated or be provided with wire or mesh screen
to prevent personnel injury or the entrance of foreign material. All windings are to be specially
treated to resist moisture, oil and salt air.
3.17.8(b) Accessibility for Repairs. The coupling is to be designed to permit removal as a unit
without moving the engine. See also 4-6-5/3.15.2.
3.17.8(c) Temperature Rating. The limits of temperature rise are to be the same as for
alternating-current generators given in 4-6-4/Table 3, except that when a squirrel-cage element is
used, the temperature of this element may reach such values as are not injurious. Depending upon
the cooling arrangements, the maximum temperature rise may occur at other than full-load rating
so that heat runs will require special consideration. For this purpose, when an integral fan is fitted,
the coupling temperatures are not to exceed the limits in 4-6-4/Table 3 when operated continuously
at 70% of full-load rpm, full excitation and rated torque. Temperature rises for insulation materials
above 180°C (356°F) will be considered in accordance with 4-6-1/13.11.
3.17.8(d) Excitation. Excitation is to be provided as required for propulsion generators. See
4-6-4/3.21.1, 4-6-4/3.23.1 and 4-6-5/3.17.6.
3.17.8(e) Control Equipment. Electric-coupling control equipment is to be combined with the
prime mover speed and reversing control and is to include a two-pole disconnect switch, short-
circuit protection only, ammeter for reading coupling current, discharge resistor and interlocking
to prevent energizing the coupling when the prime mover control levers are in an inappropriate
position.
3.17.8(f) Nameplates. Nameplates of corrosion-resistant material are to be provided in an
accessible position of the electric coupling and are to contain the following typical details:
• Manufacturer’s name, serial number and frame designation
• Rated output and type of rating
• Ambient temperature range
• Rated voltage, speed and temperature rise
• Rated exciter voltage and current
3.17.9 Semiconductor Converters for Propulsion (2007)
3.17.9(a) General. In general, semiconductor converters are to comply with the requirements of
a relevant industry standard, such as the IEC 60146 Series. Design of the cooling systems is to
apply the ambient air temperature of 45°C and ambient sea water temperature of 32°C.
3.17.9(b) Testing and Inspection. Semiconductor converters for propulsion systems are to be tested
to the type test requirements of the relevant standard, in the presence of and inspected by the
Surveyor, preferably at the plant of the manufacturer. If the standard is the IEC 60146 Series, then
type tests are to include the Insulation Test, Light Load & Function Test, Rated Current Test,
Power Loss, Temperature Rise Test and checking the Auxiliary Devices, Properties of the Control
Equipment and Protective Devices. Duplicate units of previously tested semiconductor converters
are to be tested to the routine test requirements of the relevant standard, in the presence of and
inspected by the Surveyor, preferably at the plant of the manufacturer. If the standard is the IEC
60146 Series, then the Routine Tests are to include the Insulation Test and Light Load & Function
Test and checking the Auxiliary Devices, Properties of the Control Equipment and Protective
Devices.
3.17.9(c) Forced Cooling. Semiconductor converters that are provided with forced ventilation or
forced water cooling are to be provided with a means for monitoring the cooling system, such as
cooling medium temperature. In case of failure of the cooling system, an audible and visible
alarm is to be initiated at the propulsion motor control position and the current should be reduced
automatically to avoid overheating.

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3.17.9(d) Additional Requirements for Water Cooled Converters. Semiconductor converters that
are provided with water cooling are to be provided with a means to detect leakage. In case of
leakage, an audible and visible alarm is to be initiated at the propulsion motor control position.
Further, means to contain any leakage are to be provided so that the water does not cause a failure
of the converter or any other electrical equipment located near the converter.
3.17.10 Reactors and Transformers for Semiconductor Converters
3.17.10(a) General. Interphase reactors and transformers used with semiconductor converters are
to conform with the requirements of 4-6-4/9.1.1, 4-6-4/9.1.2(c), 4-6-4/9.3, 4-6-4/9.5.1 and 4-6-4/9.5.2,
and the following.
3.17.10(b) Voltage Regulation. Means to regulate transformer output voltage are to be provided
to take care of increase in converter forward resistance and, in addition, to obtain the necessary
performance characteristics of the converter unit in which the transformer is used.
3.17.10(c) High Temperature Alarm. Interphase reactors and transformers used with the
semiconductor converters for main and auxiliary propulsion systems are to be provided with high
temperature alarm at the switchboard or the propulsion control station. The setting value of the
alarm is to be determined by their specific insulation class and is not to exceed the temperature
corresponding to the limit listed in 4-6-4/Table 8.
3.17.11 Switches
3.17.11(a) General Design. All switches are to be arranged for manual operation and so designed
that they will not open under ordinary shock or vibration. Contactors, however, may be operated
pneumatically, by solenoids or other means in addition to the manual method which is to be provided,
unless otherwise approved.
3.17.11(b) Generator and Motor Switches. Switches for generators and motors are preferably to
be of the air-break type, but for alternating-current systems, where they are to be designed to open
full-load current at full voltage, oil-break switches using nonflammable liquid may be used if provided
with leak-proof, non-spilling tanks.
3.17.11(c) Field Switches. Where necessary, field switches are to be arranged for discharge resistors
unless discharge resistors are permanently connected across the field. For alternating-current systems,
means are to be provided for de-energizing the excitation circuits by the unbalance relay and ground
relay.
3.17.12 Propulsion Cables
3.17.12(a) Conductors. The conductors of cables external to the components of the propulsion
plant, other than cables and interconnecting wiring for computers, data loggers or other automation
equipment requiring currents of very small value, are to consist of not less than seven strands and
have a cross-sectional area of not less than 1.5 mm2 (2,960 circ. mils).
3.17.12(b) Insulation Materials. Ethylene-propylene rubber, cross-linked polyethylene or silicone
rubber insulated cables are to be used for propulsion power cables, except that polyvinyl chloride
insulated cables may be used where the normal ambient temperature will not exceed 50°C (122°F).
3.17.12(c) Braided Metallic Armor and Impervious Metallic Sheaths (1998). Propulsion cables
need not have braided metallic armor nor impervious metallic sheaths. Where metallic sheaths are
provided, they are not to be used with single alternating current cables.
3.17.12(d) Inner Wiring. The insulation of internal wiring in main control gear, including
switchboard wiring, shall be of flame-retardant quality.
3.17.12(e) Testing. All propulsion cables, other than internal wiring in control gears and
switchboards, are to be subjected to dielectric and insulation tests in the presence of the Surveyor.

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3.19 Dock and Sea Trials

Complete tests are to be carried out, including duration runs and maneuvering tests, which should include a
reversal of the vessel from full speed ahead to full speed astern, tests for operation of all protective devices
and stability tests for control. All tests necessary to demonstrate that each item of plant and the system as a
whole are satisfactory for duty are to be performed. Immediately prior to trials, the insulation resistance is
to be measured and recorded.

5 Three-wire Dual-voltage DC System

5.1 Three-wire DC Ship’s Generators

Separate circuit-breaker poles are to be provided for the positive, negative, neutral and also for the equalizer
leads, unless protection is provided by the main poles. When equalizer poles are provided for the three-
wire generators, the overload trips are to be of the algebraic type. No overload trip is to be provided for the
neutral pole, but it is to operate simultaneously with the main poles. A neutral overcurrent relay and alarm
system is to be provided and set to function at a current value equal to the neutral rating.

5.3 Neutral Earthing

5.3.1 Main Switchboard
The neutral of three-wire dual-voltage direct-current systems is to be solidly earthed at the generator
switchboard with a zero-center ammeter in the earthing connection. The zero-center ammeter is to
have a full-scale reading of 150% of the neutral-current rating of the largest generator and be marked
to indicate the polarity of earth. The earth connection is to be made in such a manner that it will
not prevent checking the insulation resistance of the generator to earth before the generator is
connected to the bus. The neutrals of three-wire DC emergency power systems are to be earthed at
all times when they are supplied from the emergency generator or storage battery. The earthed
neutral conductor of a three-wire feeder is to be provided with a means for disconnecting and is to
be arranged so that the earthed conductor cannot be opened without simultaneously opening the
unearthed conductors.
5.3.2 Emergency Switchboard
No direct earth connection is to be provided at the emergency switchboard. The neutral bus or
buses are to be solidly and permanently connected to the neutral bus of the main switchboard. No
interrupting device is to be provided in the neutral conductor of the bus-tie feeder connecting the
two switchboards.

5.5 Size of Neutral Conductor

The capacity of the neutral conductor of a dual-voltage feeder is to be 100% of the capacity of the unearthed
conductors.

7 Electrical Plants of Less Than 75 kW

7.1 General (2006)

Electrical plants having an aggregate capacity of less than 75 kW are to comply with the following requirements
and the requirements in this Part 4, Chapter 6, as applicable – except 4-6-1/17, 4-6-2/1.3, 4-6-2/1.5, 4-6-2/3,
4-6-2/5, 4-6-2/7.1.6(b), 4-6-2/9.1.5, 4-6-2/11.5, 4-6-2/11.7, 4-6-2/13.3, 4-6-2/15, 4-6-2/17.1, 4-6-2/17.3,
4-6-2/19.3, 4-6-3/1.1, 4-6-3/3.9, 4-6-4/7.15.2, 4-6-4/13 and 4-6-5/1.

7.3 Standard Details

Standard wiring practices and details, including such items as cable supports, earthing details, bulkhead
and deck penetrations, cable joints and sealing, cable splicing, watertight and explosion-proof connections
to equipment, earthing and bonding connections, etc., as applicable, are to be indicated on the submitted plans
or may be submitted in a booklet format.

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7.5 Calculations of Short-circuit Currents

In the absence of precise data, the following short circuit currents at the machine terminals are to be assumed:
7.5.1 Direct Current System
Ten times the full load current for generators normally connected (including spare) for each generator
capable of being simultaneously connected.
Six times full load current for motors simultaneously in service.
7.5.2 Alternating Current System
Ten times the full load current for generators normally connected (including spare) for each generator
capable of being simultaneously connected-symmetrical r.m.s.
Three times full load current of motors simultaneously in service.

7.7 Lightning Protection

A lightning-protection system consisting of a copper spike and a copper conductor of at least 8 mm2 (No. 8
AWC) is to be installed on each nonmetallic mast. The spike is to project at least 150 mm (6 in.) above the
uppermost part of the vessel, the conductor is to run clear of metal objects and as straight as practicable to
the metallic steel structure of the vessel.

7.9 Temperature Ratings

In the requirements contained in 4-6-5/7, an ambient temperature of 40°C (140°F) has been assumed for all
locations. Where the ambient temperature is in excess of this value, the total temperature specified is not to
be exceeded. Where equipment has been rated on ambient temperature less than that contemplated,
consideration will be given to the use of such equipment, provided the total temperature for which the
equipment is rated will not be exceeded.

7.11 Generators
Vessels using electricity for propulsion auxiliaries or preservation of cargo are to be provided with at least
two generators. These generators are not to be driven by the same engine. The capacity of the generating
sets is to be sufficient to carry the necessary load essential for the propulsion and safety of the vessel and
preservation of the cargo (if applicable) with any one generator set in reserve. Vessels having only one
generator are to be provided with a battery source to supply sufficient lighting for safety.

7.13 Emergency Source of Power

7.13.1 Capacity
The emergency source of electrical power is to have adequate capacity to provide emergency
lighting for a period of at least six hours.
7.13.2 Sources
The emergency power source may be any of the following:
i) An automatically connected or manually controlled storage battery; or
ii) An automatically or manually started generator; or
iii) Relay-controlled, battery-operated lanterns.
7.13.3 Battery Sources
Where the source of electrical power is a battery connected to a charging device with an output of
more than 2 kW, the battery is to be located as near as practicable to, but not in the same space as,
the emergency switchboard, distribution board or panel.

7.15 Cable Construction

Cables are to have copper conductors constructed in accordance with a recognized standard and are to be
of the stranded type, except sizes not exceeding 1.5 mm2 (16 AWG) may have solid conductors.

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7.17 Switchboards, Distribution Boards and Panels

7.17.1 Installation
Switchboards, distribution box panels and panels are to be installed in dry, accessible and well-
ventilated areas. Not less than 610 mm (24 in.) clearance is to be provided in front of switchboards,
distribution box panels and panels. When located at the helm or other area adjacent to or part of an
open cockpit or weather deck, they are to be protected by a watertight enclosure.
7.17.2 Instrumentation
A voltmeter, ammeter, frequency meter and voltage regulator are to be provided for each generator
installed. Control equipment and measuring instruments are to be provided as necessary to insure
satisfactory operation of the generator or generators.

7.19 Navigation Running Lights

Mast head, port, starboard and stem lights, when required, are to be controlled by a running light indicator
panel. A fused-feeder disconnect switch is to be provided. The rating of the fuses is to be at least twice that
of the largest branch fuse and greater than the maximum panel load.

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4
CHAPTER 6 Electrical Installations

SECTION 6 Specialized Vessels and Services

1 Oil Carriers

1.1 Application (2007)

i) In addition to the foregoing requirements of this Section, the following requirements are applicable
to vessels carrying oil having a flash point not exceeding 60°C (140°F).
Note: Vessels of this type are subject to the applicable requirements of 3-4-1/5.1 and 3-4-1/5.3.1. The electric
installation on bulk-oil vessels carrying oil having a flash point above 60°C (140°F), closed-cup test, will
be subject to special consideration and 4-6-6/1.21, in each case.
ii) Oil carriers subject to SOLAS are to comply with the requirements of IEC 60092-502 (1999)
“Electrical Installations in Ships – Tankers – Special Features” in lieu of the electrical safety
requirements associated with hazardous areas contained in 4-6-6/1 in accordance with Chapter II-1,
Regulation 45.11 of the 2004 Amendments to SOLAS.
iii) Vessels carrying oil having a flashpoint above 60°C subject to SOLAS are to comply with the
requirements of Clause 4.3.1 of IEC 60092-502 (1999) “Electrical Installations in Ships – Tankers
– Special Features” in accordance with Chapter II-1, Regulation 45.11 of the 2004 Amendments to
SOLAS.
iv) Vessels carrying oil having a flashpoint above 60°C subject to SOLAS are to comply with the
requirements of Clause 4.3.2 of IEC 60092-502 (1999) “Electrical Installations in Ships – Tankers
– Special Features” when cargoes are heated to a temperature within 15°C of their flashpoint in
accordance with Chapter II-1, Regulation 45.11 of the 2004 Amendments to SOLAS.

1.3 Earthed Distribution Systems

An earthed distribution system is not to be used, except for the following applications.
i) Earthed intrinsically-safe circuits.
ii) Power supplied, control circuits and instrumentation circuits where technical or safety reasons
preclude the use of a system without an earthing connection, provided the current in the hull is
limited to 5 amperes or less in both normal and fault conditions.
iii) Limited and locally earthed systems, provided that any possible resulting current does not flow
directly through any hazardous areas.
iv) Alternating-current power networks of 1 kV root mean square (r.m.s.) (line to line) and over,
provided that any possible resulting current does not flow directly through any hazardous areas.

1.5 Hazardous Areas

The hazardous areas include: (see also 4-6-6/Figure 1)
i) Cargo tanks and cargo piping
ii) Cofferdams, and permanent (for example, segregated) ballast tanks adjacent to cargo tanks
iii) Cargo pump rooms
iv) Compartments for cargo hoses

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v) Enclosed or semi-enclosed spaces immediately above cargo pump rooms or having bulkheads above
and in line with cargo bulkheads, where permitted by Reg. II-2/56 of SOLAS 1974, as amended
vi) Enclosed or semi-enclosed spaces, immediately above cargo pump rooms, or above vertical cofferdams
adjacent to cargo tanks, unless separated by a gas-tight deck and suitably mechanically ventilated,
where permitted by Reg. II-2/56 of SOLAS 1974, as amended
vii) Spaces, other than cofferdams, adjacent to and below the top of a cargo tank (for example, trunks,
passageways and holds)
viii) Areas on open decks, or semi-enclosed spaces on open decks, within 3 m of any cargo tank outlets,
gas or vapor outlet, cargo manifold valve, cargo valve, cargo pipe flange, cargo pump room entrances
or cargo pump room ventilation openings
Note: Such areas are, for example, all areas within 3 m of cargo tank hatches, sight ports, tank cleaning opening,
valve openings, sounding pipes, cargo vapor outlets, cofferdam of cargo tanks.
ix) Areas on open deck within spillage coaming surrounding cargo manifold valves and 3 m beyond
these and other coamings intended to keep spillages clear of accommodation and service spaces,
up to a height of 2.4 m above the deck
x) Areas on open deck over all cargo tanks (including all ballast tanks within cargo tank area) and to
the full breadth of the vessel plus 3 m fore and aft on open deck, up to a height of 2.4 m above the
deck which do not belong to the hazardous areas defined in 4-6-6/1.5viii) and 4-6-6/1.5ix)
xi) Enclosed or semi-enclosed spaces, having an opening into any hazardous area unless 4-6-6/1.7 is
applicable
xii) Enclosed or semi-enclosed spaces containing no source of hazard and having openings (including
those for ventilating systems) into a hazardous area described in 4-6-6/1.5xiii)
xiii) Areas on open deck:
• A spherical-shaped area within 3 m to 5 m of pressure/vacuum valves used for small flow of
vapor due to normal thermal variations in the tanks, or
• A cylindrical-shaped area of infinite height within 3 m to 10 m of vent outlets for free flow of
vapor mixtures and high velocity vent outlets for passage of large amounts of vapor, air or inert
gas mixtures, which do not belong to the hazardous areas defined in 4-6-6/1.5viii), 4-6-6/1.5ix)
and 4-6-6/1.5x).

FIGURE 1
Typical Hazardous Areas on Open Deck [See 4-6-6/1.5]
3m
5m
During flow of Open Deck
small volume
3m During cargo loading and
ballasting and discharging

3m 3m
10 m 10 m 3m

2.4 m 2.4 m 2.4 m

3m 3m

Coaming in way Vent Stack 3m

P/V Vent Hatchway
of cargo manifold (High velocity valve
or free flow)
Cargo Tank

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1.7 Enclosed Spaces Separated from Hazardous Areas by Air Locks

Equipment in enclosed spaces other than category A machinery spaces having access from open deck areas
4-6-6/1.5viii), 4-6-6/1.5ix), 4-6-6/1.5x) and 4-6-6/1.5xiii) need not be of a certified safe type, provided the
access is through a double door air lock and the arrangements comply with either type 1 or type 2 as follows:
1.7.1 Type 1
1.7.1(a) The air lock is to consist of two gas tight steel doors of self-closing type with no holding
back arrangement, spaced at least 1.5 m (5 ft) but not more than 2.5 m (8 ft) apart and is to be
provided with mechanical ventilation.
1.7.1(b) The nonhazardous space is to be maintained at overpressure relative to the external
hazardous area.
1.7.1(c) The relative overpressure or air flow is to be continuously monitored and so arranged
that in the event of ventilation failure, an audible and visual alarm is given at a manned control station
and the electrical supply to all equipment not of an approved explosion-proof or intrinsically-safe
type is automatically disconnected. A time delay on the disconnect will be considered, where
necessary.
1.7.1(d) Equipment for maneuvering, anchoring and mooring, as well as the emergency fire pump
and any other electrical equipment, the shutdown of which could in itself introduce a hazard, is not
to be located in spaces covered by this section unless the equipment is of an approved explosion-
proof or intrinsically-safe type.
1.7.2 Type 2
1.7.2(a) The air lock is to consist of two gas tight steel doors of self closing type with no holding
back arrangement, spaced at least 1.5 m (5 ft) but not more than 2.5 m (8 ft) apart.
1.7.2(b) The non-hazardous space and the air lock are to be maintained at overpressure relative to
the external hazardous area by independent mechanical ventilation systems arranged such that a single
failure will not result in the simultaneous loss of overpressure in both the nonhazardous space and
the air lock.
1.7.2(c) Failure of either ventilation system described in 4-6-6/1.7.2(b) is alarmed at a normally
manned control station.

1.9 Installation of Equipment and Cables

1.9.1 General
Electrical equipment and wiring are not to be installed in any hazardous areas unless essential for
operation purposes. In such cases, the installation of equipment and wiring are to comply with
4-6-6/Table 1.
1.9.2 Cables
All cables installed within the hazardous areas described in 4-6-6/1.5 are to be sheathed with a
nonmetallic external impervious sheath over a metallic braiding or a metallic armoring or to be of
mineral-insulated copper- or stainless steel-sheathed type. A nonmetallic impervious sheath is to
be applied over the metallic braiding, armoring or sheathing of all cables which may be subject to
corrosion. Cables installed on open deck or on fore and aft gangways are to be protected against
mechanical damage. Cable and protective supports are to be so installed as to avoid strain or
chafing and due allowance made for expansion or working of the structure.
1.9.3 Sea Depth Sounder, Speed Log, and Impressed Current Cathodic Protection Systems (2005)
Hull fittings containing transducers for electrical depth sounding or speed log devices or containing
terminals or shell penetrations for anodes or electrodes of an impressed current cathodic protection
system for underwater hull protection are not to be installed in any cargo tanks of an oil carrier.
However, it may be installed in hazardous areas, as permitted by 4-6-6/Table 1, provided the following
are complied with:

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1.9.3(a) Hull fittings containing terminals or shell-plating penetrations are to be housed within a
gas-tight enclosure and are not to be located adjacent to cargo tank bulkhead
1.9.3(b) The box containing actual electrical connection of the cable, such as terminal box or junction
box, is to be filled with insulating material, such as silicon grease, silicon sealing or equivalent
and also to be of gastight construction;
1.9.3(c) All associated cables passing through these spaces are to be installed in extra-heavy steel
pipe with gas-tight joints (no flanged joints), and with corrosion resistant coating up to, and including
the underside of the main deck;
1.9.3(d) Cable gland with gastight packing is to be provided for the cable at both ends of the cable
conduit pipe; and
1.9.3(e) Cable inside the vertical cable conduit pipe is to be suitably supported, e.g., by sand-filling,
or by strapping to a support-wire. Alternatively, the cable inside the vertical conduit pipe may be
accepted without provided support if the mechanical strength of the cable is sufficient to prevent
cable damage due to the cable weight within the conduit pipe under continuous mechanical load.
Supporting documentation is to be submitted to verify the mechanical strength of the cable with
respect to the cable weight inside the conduit.

1.11 Spaces Above Forepeak Tank

Equipment located in enclosed spaces above forepeak tanks is to be of an approved explosion-proof or
intrinsically-safe type if there is direct access from the space into the forepeak tank with any of the
following arrangements:
i) The forepeak tank is not separated from cargo oil tanks by a cofferdam.
ii) The forepeak tank is served by piping which also serves other spaces or tanks adjacent to cargo oil
tanks, unless the only opening to the forepeak tank from the space above is through a gastight
manhole and all other penetrations (i.e., sounding pipes) are led to the weather.

1.13 Cargo Oil Pump Room

1.13.1 Ventilation
1.13.1(a) System and Arrangement. Cargo oil pump rooms are to have a mechanical extraction
ventilating system and ducting, in accordance with 4-6-6/1.13.1i), 4-6-6/1.13.1ii), 4-6-6/1.13.1iii),
and 4-6-6/1.13.1iv) below.
i) Lower Intake. Lower (main) intakes are to be located at the lowest floor level. The number
of air changes through the main intake with the damper in item ii) closed is to be at least
twenty changes per hour based on the gross volume of the pump room.
ii) Emergency Intake. An emergency intake is to be provided at approximately 2 m (6.5 ft)
above the lowest floor with damper capable of being opened or closed from the exposed
main deck and lowest floor level so that it can be used when the lower intakes are not
available. The air changes in that condition is to be at least fifteen changes per hour.
iii) Dampers. Where the ratio of areas of the upper emergency intake and lower main intakes
is such that the required number of respective air changes in items i) and ii) above can be
obtained, the dampers may not be required.
iv) Floor Plate. Floors are to be open grating type to allow the free flow of air. See 5C-1-1/5.25
and 5C-2-1/5.23 of the Steel Vessel Rules.
1.13.1(b) Fan Motors and Fans. Fan motors are to be located outside of the pump room and
outside of the ventilation ducts. Fans are to be of nonsparking construction in accordance with
4-6-3/11.7. Provision is to be made for immediate shutdown of the fan motors upon release of the
fire extinguishing medium.

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1.13.2 Gas Detection (1998)

A system for continuously monitoring the concentration of hydrocarbon gases in the pump room is
to be fitted. A system utilizing sequential sampling is acceptable, provided the system is dedicated
solely to the pump room, thereby minimizing the sampling cycle. Sampling points or detector
heads are to be located in the exhaust ventilation duct and lower parts of the pump room at the
floor level. The system is to give a visual indication of the level of concentration of hydrocarbon
gases and an audible alarm if the concentration exceeds 10% of the lower explosive limit. Such
alarm is to be provided in the cargo control room and on the navigation bridge.
1.13.3 Lighting (2002)
1.13.3(a) Lighting fitted outside the pump room. As far as practicable, the lighting fixtures for
pump room spaces are to be permanently wired and fitted outside of the pump room, except as
noted below. Pump rooms adjacent to engine rooms or similar safe spaces may be lighted through
substantial glass lenses or ports permanently fitted in the bulkhead or deck.
The construction of the glass lens port is to be as follows:
• Capable of maintaining watertight and gastight integrity of the bulkhead and deck.
• Suitably protected from mechanical damage.
• Provided with a steel cover capable of being closed and secured on the side of the safe space.
• Both the glass lens and its sealing arrangement will not be impaired by working of the hull.
• Structural strength of the pierced bulkhead or deck is suitably reinforced.
See also 5C-1-1/5.11 and 5C-2-1/5.9 of the Steel Vessel Rules.
1.13.3(b) Lighting fitted inside the pump room. As an alternative to 4-6-6/1.13.3(a), certified safe
lighting fixtures (see 4-6-6/Table 1) may be installed in the pump room, provided they are wired
with moisture-resisting jacketed (impervious-sheathed) and armored or mineral-insulated metal-
sheathed cable. Lighting circuits are to be so arranged that the failure of any one branch circuit will
not leave these spaces in darkness. All switches and protective devices are to be located outside of
the pump room. See also 4-6-3/11.1.2 for lighting circuits in hazardous areas.
1.13.3(c) Lighting/Ventilation Interlock (1 July 2002). For oil carriers 500 GT and over, lighting
in cargo pump rooms, except emergency lighting, is to be interlocked with the ventilation system
such that the ventilation system is to be in operation when switching on the lighting. Failure of the
ventilation system is not to cause the lighting to go out.
1.13.4 Cable Installation
Where it is necessary for cables, other than those of intrinsically-safe circuits and those cables
supplying lighting fixtures in the pump room, to pass through cargo pump rooms, they are to be
installed in extra-heavy steel pipes or other arrangements providing the same degree of gas tightness
and protection.

1.15 Gas Monitoring System Installation (1998)

For gas monitoring of the cargo area, sampling type gas analyzing units which are not intended for a hazardous
location may be located outside of cargo areas (e.g., in cargo control room, navigation bridge or engine room)
when mounted on the inside of the front bulkhead and subject to compliance with the following:
i) Sampling lines are not to pass through gas safe spaces, unless permitted by 4-6-6/1.15v).
ii) The non-safe type gas analyzing unit is to be installed in a safe area and the gas sampling lines are
to be fitted with flame arresters. Sample gas is to be led to the atmosphere. The outlets are to be
fitted with flame screens and are to be located in a safe location away from ignition sources. The
area within 3 m (10 ft) of the outlet pipe is to be considered a hazardous location. See 4-6-6/1.5viii)
and 4-6-6/Table 1, item f1.
iii) Where sampling pipes pass through bulkheads separating safe and dangerous areas, the penetrations
are to be of an approved type having fire integrity at least as effective as the bulkhead. A manual
isolation valve is to be fitted at each penetration on the gas safe side.

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iv) The gas detection equipment, including sampling piping, sampling pumps, solenoids, analyzing units,
etc., are to be contained in a gas-tight steel cabinet monitored by its sampling point. The entire gas
analyzing unit is to be shut down when the gas concentration inside of the cabinet reaches 30% of
the lower flammability limit.
v) Where it is impracticable to mount the cabinet on the front bulkhead, sampling pipes are to be of
steel or other equivalent material and without any detachable connections except for the isolating
valves at the bulkhead and analyzing units. Runs of sampling pipes within safe space are to be of
the shortest possible length.

1.17 Pipe Tunnel or Duct Keel

1.17.1 Ventilation
Where a permanent lighting system is installed, a mechanical ventilating system capable of providing
at least eight air changes per hour based on the gross volume of the space is to be provided. The
system is to have mechanical exhaust, natural or mechanical supply and ducting as required to
effectively purge this space and all connecting access trunks. Fan motors are to be located outside
of the space in question and outside the ventilation ducts. Fans are to be of non-sparking
construction, in accordance with 4-6-3/11.7.
1.17.2 Lighting
Where a permanent lighting system is installed in enclosed spaces such as pipe tunnels, double
bottoms or duct keels, it is to be in accordance with 4-6-6/1.13.3. The switches are to be accessible
to authorized personnel only. See also 4-6-3/11.1.2.
1.17.3 Gas Detection System
An approved gas detection system with a visual indication of the gas concentration and an alarm
for the high level is to be provided in accordance with 4-6-6/1.13.2 so as to adequately monitor the
double bottom (pipe trunk) spaces.

1.19 Gas Detection for Double Hull and Double Bottom Spaces in the Cargo Area (1999)
Suitable portable instruments for measuring oxygen and flammable vapor concentrations are to be provided.
Where the atmosphere in double hull spaces cannot be reliably measured using flexible gas sampling hoses,
such spaces are to be fitted with permanent gas sampling lines. The materials of construction and dimensions
of gas sampling lines are to be such as to prevent restriction. Where plastic materials are used, they are to
be electrically conductive.

1.21 Integrated Cargo and Ballast Systems – All Cargo Flash Points (2004)
1.21.1 Application
The following requirements are applicable to integrated cargo and ballast systems installed on tankers
(i.e., cargo ships constructed or adapted for the carriage of liquid cargoes in bulk), regardless of
the flash point of the cargoes. The integrated cargo and ballast system means any integrated hydraulic
and/or electric system used to drive both cargo and ballast pumps (including active control and
safety systems and excluding passive components, e.g., piping).
1.21.2 Functional Requirements
The operation of cargo and/or ballast systems may be necessary, under certain emergency
circumstances or during the course of navigation, to enhance the safety of tankers. As such,
measures are to be taken to prevent cargo and ballast pumps becoming inoperative simultaneously
due to a single failure in the integrated cargo and ballast system, including its control and safety
systems.

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1.21.3 Design Features

The following design features are to be fitted:
i) The emergency stop circuits of the cargo and ballast systems are to be independent from
the circuits for the control systems. A single failure in the control system circuits or the
emergency stop circuits are not to render the integrated cargo and ballast system inoperative.
ii) Manual emergency stops of the cargo pumps are to be arranged in such a way that they do
not cause the ballast pump power pack to stop and thus make the ballast pumps inoperable.
iii) The control systems are to be provided with a backup power supply, which may be satisfied
by a duplicate power supply from the main switchboard. The failure of any power supply
is to provide audible and visible alarm activation at each location where the control panel
is fitted.
iv) In the event of failure of the automatic or remote control systems, a secondary means of
control is to be made available for the operation of the integrated cargo and ballast system.
This is to be achieved by manual overriding and/or redundant arrangements within the
control systems.

3 Vessels Carrying Coal in Bulk

3.1 Application
3.1.1 General (1998)
The foregoing requirements in this Section and the requirements in 4-6-6/3.3 and 4-6-6/3.5 are
applicable to vessels intended to carry coal in bulk by which an explosive and flammable atmosphere
may be created.
3.1.2 Flag Administration (1998)
Attention is directed to the requirements for the carriage of coal in bulk in the IMO BC Code and
their application as may be prescribed by the vessel’s flag Administration. If requested by the
vessel’s Owner and authorized by the Administration, ABS will review the plans and carry out
surveys in accordance with the above Code on behalf of the Administration.

3.3 Hazardous Areas

Space in which combustible and explosive dust/gas and air mixture is likely to occur in normal operation
are to be identified as hazardous areas, such as cargo hold spaces, spaces with a direct opening to cargo
hold spaces, or areas within 3 m (10 ft) of cargo hold ventilation outlets.

3.5 Installation of Equipment

3.5.1 Classified Electrical Equipment in Hazardous Area
Machinery, all electrical power, control and safety devices and wiring installed in locations where
an explosive and flammable atmosphere (as may occur in spaces for coal) is expected to exist are
to have a temperature classification T4 or higher (maximum surface temperature 132°C (275°F) or
lower) and are to be suitable for operation in at least a Group IIA environmental classification, as
defined in IEC Publication 60079-12.
3.5.2 Internal Combustion Engines in Hazardous Area
Where essential for operational purposes, the installation of internal combustion engines in hazardous
areas will be subject to special consideration. In all instances, exhaust outlets are to be outside of
all hazardous areas, excluding that produced by the exhaust outlet itself, and air intakes are to be
not less than 3 m (10 ft) from hazardous areas.

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3.5.3 Cargo Hold (1998)

3.5.3(a) Instruments for Measuring (1998). Readings are to be obtainable without entry into the
cargo hold and without endangering the cargo and cargo hold’s atmosphere. Instruments for
measuring the following are to be provided:
i) Concentration of methane in the atmosphere,
ii) Concentration of oxygen in the atmosphere,
iii) Concentration of carbon monoxide in the atmosphere,
iv) pH value of cargo hold bilge samples.
Note: In addition to the instruments specified in 4-6-6/3.5.3(a), it is recommended that consideration should be
given by the Owner/designers to provide the means for measuring the temperature of the cargo in the
range of 0°C (32°F) to 100°C (212°F), where it is intended to carry self-heating coal. Such arrangements
should permit the temperature of the coal to be measured during the loading operations and during the
voyage without requiring entry into the cargo space.
3.5.3(b) Cargo Atmosphere Measuring Equipment (1998). An instrument for measuring methane,
oxygen and carbon monoxide concentrations is to be provided, together with an aspirator, flexible
connection, a length of tubing and means for sealing the sampling hole in order to enable a
representative sample to be obtained from within the hatch cover surroundings. Alternative means
for obtaining a representative sample will be considered.
3.5.3(c) Sampling Points (1998). Sampling points are to be provided for each hold, one on the
port side and another on the starboard side of the hatch cover, as near to the top of the hatch cover
as possible. Each sampling point is to be fitted with a screw cap and a threaded stub of approximately
12 mm (0.5 in.) bore, welded to the side of the hatch cover to prevent ingress of water and air.
Alternative sampling point arrangements/details will be considered.
3.5.3(d) Warning Plate (1998). Permanent warning plate is to be installed in conspicuous places
in cargo areas to state that smoking, naked flames, burning, cutting, chipping, welding or other sources
of ignition are prohibited.

5 Cargo Vessels Carrying Motor Vehicles with Fuel in Their Tank

5.1 Application
In addition to the foregoing requirements in this Section, the following requirements are applicable to the
cargo spaces carrying motor vehicles with fuel in their tanks.

5.3 Ventilation System

5.3.1 Arrangement
The ventilating system for enclosed spaces intended for the carriage of motor vehicles with fuel in
their tanks for their own propulsion is to be independent from other ventilation systems and is to
be capable of being controlled from a position outside of the space.
5.3.2 Capacity
An effective power ventilation system, sufficient to give at least six air changes per hour based on
the volume of empty enclosed spaces in which vehicles are to be transported or stored, is to be
provided. See also 4-6-6/5.5.2.
5.3.3 Fans
Exhaust fans are to be of non-sparking construction in accordance with 4-6-3/11.7.
5.3.4 Material and Arrangement of Ducts
Ventilation ducts, including dampers, are to be of steel. Ducts serving spaces capable of being
sealed are to be separated for such space.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 6 Specialized Vessels and Services 4-6-6

5.3.5 Exhaust Inlet and Outlet

Inlet for exhaust ducts are to be located within 450 mm (17.75 in.) above the vehicle deck. The
outlet is to be sited in a safe position, having regard to the source of ignition near the outlet.
5.3.6 Emergency Shutdown
Arrangements are to be provided to permit a rapid shutdown and effective closure of the ventilation
system in case of fire, taking into account the weather and sea conditions. See also 4-6-6/5.3.1.
5.3.7 Navigation Bridge Indication
Means are to be provided on the navigation bridges or other appropriate locations to indicate any
loss of the ventilating capacity.
5.3.8 Passenger Vessels
For passenger vessels, the following requirements are to be complied with, as applicable.
5.3.8(a) Special Category Spaces. The protection of all special category spaces, as defined below,
is to comply with Regulations II-1/23-2, II-1/42-1 and II-2/20 of 1974 SOLAS, as amended.
Special Category Spaces are those enclosed spaces above or below the bulkhead deck intended for
the carriage of motor vehicles with fuel in their tanks for their own propulsion, into and from which
such vehicles can be driven and to which passengers have access.
5.3.8(b) Protection of Cargo Spaces, Other than Special Category Spaces, Intended for the Carriage
of Motor Vehicles with Fuel in Their Tanks for Their Own Propulsion. All cargo spaces (other than
special category spaces) containing motor vehicles with fuel in their tanks for their own propulsion
are to comply with Regulations II-1/23-2, II-1/42-1 and II-2/20 of 1974 SOLAS, as amended.

5.5 Location and Type of Equipment

5.5.1 Certified Safe Type Equipment
Except as provided for in 4-6-6/5.5.2 below, electrical equipment and wiring within the enclosed
vehicle spaces referred to in 4-6-6/5.3.1 are to be increased-safety, explosion-proof or intrinsically-
safe type.
5.5.2 Alternative Arrangements
Except for a distance within 450 mm (17.75 in.) above a platform that does not have openings of
sufficient size permitting penetration of petroleum gases downward, electrical equipment of a type
so enclosed and protected as to prevent the escape of sparks, e.g., protection degree of IP55 or
equivalent may be permitted as an alternative, provided the ventilating system is so designed as to
provide continuous ventilation of the cargo spaces at the rate of at least ten air changes per hour
and on the assumption that the system will be so operated whenever vehicles are carried onboard.
5.5.3 Equipment in Ducts from Vehicle Space
Electrical equipment and wiring installed within an exhaust duct are to be increased-safety,
explosion-proof or intrinsically-safe type.

7 Ro-Ro Vessels

7.1 Application
In addition to the foregoing requirements in this Section, the following requirements are applicable to the
vessels of roll-on/roll-off (ro-ro) type.

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Part 4 Vessel Systems and Machinery
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Section 6 Specialized Vessels and Services 4-6-6

7.3 Ro-Ro Cargo Spaces

7.3.1 Ventilation
Closed ro-ro cargo spaces, as defined in Regulation II-2/3.12 of SOLAS 1974 as amended, are to
have ventilation systems in compliance with the applicable requirements in 4-6-6/5.3.
7.3.2 Carriage of Motor Vehicles with Fuel in Their Tank
Closed ro-ro spaces intended for the carriage of motor vehicles with fuel in their tanks for their
own propulsion are to meet the requirements in 4-6-6/5.

9 Gas Carriers or Chemical Carriers

9.1 Gas Carriers

For vessels carrying liquefied gases at or near atmospheric pressure and at temperature below atmospheric,
electrical installations are to be in accordance with Part 5C, Chapter 8 of the Steel Vessel Rules.

9.3 Chemical Carriers

For vessels carrying hazardous chemicals in bulk, electrical installations are to be in accordance with Part
5C, Chapter 9 of the Steel Vessel Rules. See also 4-6-6/1.9.3 of these Rules.

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Part 4 Vessel Systems and Machinery
Chapter 6 Electrical Installations
Section 6 Specialized Vessels and Services 4-6-6

TABLE 1
Electrical Equipment in Hazardous Areas for Oil Carriers [See 4-6-6/1.9.1]
Hazardous Area Acceptable Electrical Equipment
Cargo tanks and cargo piping as defined by a1 Category “ia” intrinsically-safe apparatus and its associated wiring
4-6-6/1.5. only.
Cofferdams and permanent (for example, b1 Category “ia” intrinsically-safe apparatus and its associated wiring.
segregated) ballast tanks adjacent to cargo b2 Hull fittings containing transducers for electrical depth sounding or
tanks, as defined by 4-6-6/1.5ii). log devices or containing the terminals. See 4-6-6/1.9.3.
b3 Shell penetrations for anodes or electrodes of an impressed current
cathodic protection system for underwater hull protection. See
4-6-6/1.9.3.
Cargo pump rooms, as defined by 4-6-6/1.5iii). c1 Intrinsically-safe apparatus.
c2 Electrical devices as described in items b2 and b3 above this Table.
c3 Explosion-proof lighting fixtures. See 4-6-3/11.1.2 and 4-6-6/1.13.3.
c4 Explosion-proof type audible and/or visual devices for
communication, general alarm and fire extinguishing medium release
alarm.
c5 Through-run of cables in extra-heavy pipe. See 4-6-6/1.13.4.
Compartments for cargo hoses, as defined by d1 Intrinsically-safe apparatus.
4-6-6/1.5iv). d2 Explosion-proof type lighting fixtures. See 4-6-3/11.1.2.
Enclosed or semi-enclosed spaces, as defined by
4-6-6/1.5v) and 4-6-6/1.5vi). d3 Through-runs of cable.
Spaces adjacent to and below the top of cargo e1 Intrinsically-safe apparatus.
tank, except for cofferdams, as defined by e2 Electrical devices as described in items b2 and b3 of this Table.
4-6-6/1.5vii).
e3 Explosion-proof type lighting fixtures. See 4-6-3/11.1.2 and
4-6-6/1.17.2.
e4 Explosion-proof type audible and/or visual devices for
communication, general alarm and fire extinguishing medium release
alarm.
e5 Through-run of cable; excepting those for intrinsically-safe circuits,
such cables require special consideration.
Areas on open deck or semi-enclosed spaces on f1 Explosion-proof, intrinsically-safe, increased safety or pressurized
open deck, as defined by 4-6-6/1.5viii). type equipment suitable for use on open deck.
Areas on open deck as defined by 4-6-6/1.5ix) f2 Through-runs of cables without expansion bends in these areas.
Areas on open deck over all cargo tanks, g1 Explosion-proof, intrinsically safe, increased safety or pressurized
including all ballast tanks within cargo tank type equipment suitable for use on open deck.
area, as defined by 4-6-6/1.5x). g2 Through-runs of cables.
Enclosed or semi-enclosed spaces having an h1 Explosion-proof or intrinsically-safe type equipment.
opening into any hazardous area, as defined by
4-6-6/1.5xi).
Enclosed or semi-enclosed spaces (not i1 Explosion-proof, intrinsically safe, increased safety or pressurized
containing a source of hazard) having openings type equipment suitable for use on open deck.
to hazardous areas, as defined by 4-6-6/1.5xii).
Areas on open deck, as defined by 4-6-6/1.5xiii),
which are outside the hazardous areas in
4-6-6/1.5viii), 4-6-6/1.5ix) and 4-6-6/1.5x).

294 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Chapter 7: Shipboard Automatic or remote Control and Monitoring Systems

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

CONTENTS
SECTION 1 General................................................................................................ 300
1 Scope ..............................................................................................300
3 Propulsion Class Notations.............................................................300
3.1 Vessels ≥ 500 GT and ≤ 46 m (150 ft) in Length ......................... 300
5 Definitions .......................................................................................301
5.1 Machinery Space......................................................................... 301
5.3 Manned Space ............................................................................ 301
5.5 Automatic Control........................................................................ 301
5.7 Remote Control ........................................................................... 301
5.9 Local Control ............................................................................... 301
5.11 Remote Station............................................................................ 301
5.13 Centralized Control and Monitoring Station ................................. 301
5.15 Instrumentation............................................................................ 301
5.17 Monitoring.................................................................................... 301
5.19 Display Systems.......................................................................... 301
5.21 Alarm ........................................................................................... 301
5.23 Summary-alarm........................................................................... 301
5.25 Safety Systems ........................................................................... 302
5.27 Emergency Shutdown Systems................................................... 302
5.29 Fail-safe....................................................................................... 302
5.31 Independent ................................................................................ 302
5.33 Computer-based System............................................................. 302
5.35 Nonvolatile Memory..................................................................... 302
5.37 Computer Monitor (Video Display Unit) ....................................... 302
5.39 ABS Type Approval Program ...................................................... 302
5.41 Integrated Propulsion Machinery................................................. 302
7 Required Plans and Data................................................................302
9 Tests and Surveys ..........................................................................304
9.1 Installation Tests ......................................................................... 304
9.3 Periodical Surveys....................................................................... 304

SECTION 2 General Systems Design and Arrangement Requirements............ 305

1 General ...........................................................................................305
3 Automatic or Remote Control Systems...........................................305
3.1 Characteristics............................................................................. 305
3.3 Interlocks ..................................................................................... 305
3.5 Transfer of Control ...................................................................... 305
3.7 Automatic Controls ...................................................................... 305

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 3.9 Remote Controls..........................................................................305
3.11 Local Controls..............................................................................305
3.13 Suitability of Equipment ...............................................................306
5 Alarm Systems ................................................................................306
5.1 Characteristics .............................................................................306
5.3 Independence ..............................................................................306
5.5 Visual and Audible Alarm.............................................................306
5.7 Acknowledgment of Alarms .........................................................306
5.9 Disconnection and Resumption of Alarm Functions ....................306
5.11 Summary-alarms .........................................................................306
5.13 Built-in Testing .............................................................................306
5.15 Suitability of Equipment ...............................................................306
7 Safety Systems ...............................................................................307
7.1 General........................................................................................307
7.3 Characteristics .............................................................................307
7.5 Independence ..............................................................................307
7.7 Activation .....................................................................................307
7.9 Resumption of Operation.............................................................307
7.11 Override of Safety Provisions ......................................................307
7.13 Suitability of Equipment ...............................................................307
9 Computer-based Systems ..............................................................307
9.1 General........................................................................................307
9.3 Independence ..............................................................................308
9.5 Visual Display of Alarm................................................................308
9.7 Memory Capacity and Response Time........................................308
9.9 Data Loss and Corruption............................................................308
9.11 Power Supply Disruption .............................................................308
9.13 Parameters and Program Changes .............................................308
11 Supply, Arrangement and System Protection of Automatic or
Remote Control and Monitoring System.........................................309
11.1 Supply and Arrangement .............................................................309
11.3 System Protection........................................................................310
13 Communications Systems ..............................................................310
15 Equipment Construction, Design and Installation ...........................310
15.1 General........................................................................................310
15.3 Electrical ......................................................................................310
15.5 Hydraulic......................................................................................310
15.7 Pneumatic....................................................................................310
15.9 Installations..................................................................................310
17 Equipment/Components Qualifications and Trials..........................312
17.1 Equipment/Components Qualifications........................................312
17.3 Type Approval of Automatic or Remote Control and Monitoring
Equipment ...................................................................................312
17.5 Trials............................................................................................312

TABLE 1 Type Tests for Control, Monitoring and Safety Equipment ...313

FIGURE 1 Test Set-up for Conducted Low Frequency Test

(See Test No. 13 of 4-7-2/Table 1) .......................................319

296 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 SECTION 3 Automatic or Remote Propulsion Control and Monitoring
Systems .............................................................................................. 320
1 General ...........................................................................................320
3 Propulsion Control Capability .........................................................320
5 Propulsion Control Orders and Indicators.......................................320
7 Propulsion Control Command.........................................................320
9 Propulsion Control Settings Deviation ............................................320
11 Propulsion Control Power Failure ...................................................321
13 Propulsion Starting..........................................................................321
15 Remote Override of Safety Provisions............................................321
17 Critical Speeds................................................................................321
19 Emergency Shutdown.....................................................................321
21 Automatic Shutdown Alarm.............................................................321
23 Automatic Propulsion Control System ............................................322
23.1 Integrity and Manual Control Functions ....................................... 322
23.3 Threshold Warning for Safety System Activations....................... 322
25 Controls and Instrumentation on Remote Propulsion Control
Stations ...........................................................................................322
27 Trials ...............................................................................................322
27.1 Automatic/Remote Control .......................................................... 322
27.3 Independent Manual Control ....................................................... 322

SECTION 4 Vessels Classed with ACCU Notation .............................................. 323

1 General ...........................................................................................323
3 Equipment.......................................................................................323
3.1 Application................................................................................... 323
3.3 Environmental Test Conditions.................................................... 323
3.5 Environmentally Controlled Space .............................................. 323
3.7 Electric and Electronic Equipment............................................... 323
3.9 Equipment Tests ......................................................................... 324
5 Automatic Propulsion Controls .......................................................324
7 Station in Navigation Bridge ...........................................................324
9 Centralized Control and Monitoring Station ....................................325
11 Power Supply for Control and Monitoring Systems ........................325
11.1 General........................................................................................ 325
11.3 Electrical...................................................................................... 325
11.5 Power Supply Transfer ................................................................ 325
13 Continuity of Power.........................................................................325
13.1 General........................................................................................ 325
13.3 Reduced Power........................................................................... 325
15 Automatic Transferring of Vital Auxiliary Pumps ............................325
17 Propulsion Gas Turbines ................................................................326
19 Propulsion Diesel Engines ..............................................................326
19.1 Lubricating Oil ............................................................................. 326
19.3 Overspeed................................................................................... 326
19.5 Controls and Instrumentation ...................................................... 326

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 21 Electric Propulsion ..........................................................................326
23 Electrical Power Generating Machinery..........................................326
25 Fuel Oil Settling and Daily Service Tanks.......................................326
25.1 General........................................................................................326
25.3 Automatic Filling ..........................................................................326
25.5 Heating Arrangements.................................................................326
27 Propulsion and Associated Machinery Start-up..............................326
29 Arrangement and Monitoring of Machinery Space .........................327
29.1 Bilges...........................................................................................327
29.3 Fire Prevention ............................................................................327
29.5 Fire Detection and Alarm .............................................................327
31 Monitoring Station in Engineers’ Accommodation ..........................328
31.1 General........................................................................................328
31.3 Alternative Arrangement ..............................................................328
33 Firefighting Arrangements for Propulsion Machinery Space
Fires ................................................................................................328
33.1 Location .......................................................................................328
33.3 Fire-fighting Controls ...................................................................328
33.5 Fire Detection and Alarm Systems ..............................................329
33.7 Fire Alarm Call Points ..................................................................329
35 Communications .............................................................................329
37 Sea Trials ........................................................................................329
37.1 Automatic or Remote Control and Monitoring System for
Propulsion Machinery and Electrical Power Generating
Machinery ....................................................................................329
37.3 Local Control ...............................................................................329
37.5 Fire Control and Alarm System....................................................329
37.7 Bilge Detection System................................................................330
37.9 Operational Test of Propulsion Machinery...................................330

TABLE 1 Tests for Unit Certification of Control, Monitoring and

Safety Equipment..................................................................331
TABLE 2 Control Station in Navigation Bridge (Applicable to All
Classed Vessels) ..................................................................332
TABLE 3 Centralized Control and Monitoring Station (Applicable to
ACCU or ABCU Vessels)......................................................334
TABLE 4A Monitoring of Propulsion Machinery – Slow Speed
(Crosshead) Diesel Engines .................................................336
TABLE 4B Monitoring of Propulsion Machinery – Medium/High
(Trunk Piston) Speed Diesel Engines ...................................339
TABLE 5 Monitoring of Propulsion Machinery – Gas Turbine..............341
TABLE 6A Monitoring of Propulsion Machinery – Electric......................343
TABLE 6B Instrumentation and Safety System Functions in
Centralized Control Station – Generator Prime
Mover for Electric Propulsion ................................................344
TABLE 7 Monitoring of Auxiliary Prime-movers and Electrical
Generators ............................................................................346

298 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
 SECTION 5 Vessels Classed with ABCU Notation .............................................. 347
1 General ...........................................................................................347
3 Station in Navigation Bridge ...........................................................347
5 Centralized Monitoring Station........................................................347
7 Communications .............................................................................347
9 Sea Trials ........................................................................................347

SECTION 6 Vessels Less Than 500 GT Having a Length Equal or Greater

Than 20 m (65 ft)................................................................................. 348
1 General ...........................................................................................348
3 Definitions .......................................................................................348
5 Plans to be Submitted.....................................................................348
7 Electrical Cables and Console Wiring.............................................348
9 Alarms .............................................................................................349
11 Safety System.................................................................................349
13 Bridge Control of Propulsion Machinery .........................................349
13.1 General........................................................................................ 349
13.3 Local Control ............................................................................... 349
13.5 Bridge Control Indicators ............................................................. 349
15 Requirements for Periodically Unattended Propulsion Machinery
Spaces ............................................................................................349
15.1 Fire Protection ............................................................................. 349
15.3 Protection Against Flooding......................................................... 350
15.5 Alarms and Displays.................................................................... 350

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 299
PART Section 1: General

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 1 General

1 Scope (1998)
The requirements contained in this section are intended for unrestricted vessels of under 90 m (295 ft) in
length fitted with control and monitoring systems that embody various degrees of automatic or remote
control and monitoring of the propulsion machinery and propulsion-machinery space. These requirements
are in addition to those in other sections of the Rules. The following table indicates the applicability of the
relevant requirements:

Gross Tonnage (GT)

500 or over/not assigned 500 or over/assigned optional
Vessel’s Length (L) Under 500 optional ACCU or ABCU ACCU or ABCU symbol
symbol
L < 20 m (65 ft) Will be specially considered Will be specially considered —
20 m (65 ft) ≤ L Use Section 4-7-6 Use Sections 4-7-1 to 4-7-3 Use Section 4-7-4 or 4-7-5,
≤ 46 m (150 ft) as applicable
L > 46 m (150 ft) Use Section 4-7-6 Use Sections 4-9-1 and 4-9-2 Use Sections 4-9-1 to 4-9-7 of
of the Steel Vessel Rules the Steel Vessel Rules, for
ACCU or Sections 4-9-1 to
4-9-7 of SVR plus 4-7-5 for
ABCU as applicable

Consideration will be given to vessels of special design such as surface effect vessels, air cushion vessels,
etc., upon submission of manufacturer’s specification and drawings.

3 Propulsion Class Notations (1998)

Where requested by the Owner, automatic or remote control and monitoring systems for propulsion and
monitoring systems of propulsion-machinery space that comply with the relevant requirements of this
Section will be distinguished in the Record as follows. A certificate indicating the degree of automation,
particulars and operating limitations, if any, will be issued. A notation preceded by À (Maltese cross)
signifies that the installations have been assembled and installed under survey by the Surveyor. A notation
without À (Maltese cross) symbol signifies that pertinent automatic or remote control and monitoring
systems have not been assembled and installed under survey but have subsequently been surveyed and
satisfactorily reported upon by the Surveyor.

3.1 Vessels ≥ 500 GT and ≤ 46 m (150 ft) in Length

3.1.1 ACCU Notation
Automatic or remote control and monitoring systems complying with Section 4-7-4 will be
distinguished in the Record by the notation ACCU.

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Section 1 General 4-7-1

3.1.2 ABCU Notation

Automatic or remote control and monitoring systems complying with Section 4-7-5 will be
distinguished in the Record by the notation ABCU.
Note: ACCU or ABCU class notation may be granted to vessels of < 500 GT and a length of 20 m (65 ft) ≤ L ≤ 46 m
(150 ft), provided that the applicable requirements in Sections 4-7-1 through 4-7-5 of this Section are met.

5 Definitions
The following definitions apply for the purpose of this Chapter:

5.1 Machinery Space

See 4-1-1/13.

5.3 Manned Space

Means any space assigned at all times with crew members needed to locally supervise the operation of the
specific machinery or system installed in the space.

5.5 Automatic Control

Type of control which is self-regulating in carrying out ordered instruction without action by the operator.

5.7 Remote Control

Control of a device by an operator from a distance through mechanical, electrical, electronic, pneumatic,
hydraulic, electromagnetic (radio) or optical means or their combination.

5.9 Local Control

Control by an operator of machinery through a device located on or adjacent to the controlled machinery.

5.11 Remote Station

A permanent installation fitted with effective control and/or monitoring means and located at a distance
from the specific machinery.

5.13 Centralized Control and Monitoring Station

A remote station designated as the central location where the necessary instrumentation required to maintain
the control and monitoring of the specific machinery is fitted, and which is equivalent at least as if the
machinery were under local supervision.

5.15 Instrumentation
A monitoring device including sensing and transmitting component.

5.17 Monitoring
The display and alarming of the operational status of a specific machinery/system.

5.19 Display Systems

Display systems are those which display operating machinery parameter values such as pressure, temperature,
liquid flow, motor running, etc., or the sequential operation of the system’s process.

5.21 Alarm
A visual and audible signal of a predetermined out of limits parameter for the controlled and/or monitored
machinery or system.

5.23 Summary-alarm
A common alarm activated by any abnormal condition of the monitored machinery or system.

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5.25 Safety Systems

Systems which provide automatic actions in response to faults that may develop too fast to be countered by
manual intervention. The safety systems are intended to operate automatically in case of faults within the
machinery plant for the purpose of:
i) Temporarily adjusting the operation of the machinery to the prevailing conditions (by reducing the
output of the machinery), or
ii) Restoring the normal operating conditions (by starting of standby units), or
iii) Protecting the machinery from critical conditions by stopping the machinery (shutdown).

5.27 Emergency Shutdown Systems

Systems intended for manual activation in an emergency to stop a particular system’s function or machinery
operation.

5.29 Fail-safe
Fail-safe means that upon failure or malfunction of a component, subsystem or system, the output automatically
reverts to a predetermined design state of least critical consequence.

5.31 Independent
As applied to two systems, means that one system will operate with the failure of any part of the other
system including power sources and its supply connection. However, for electrical systems which are not
required to have an emergency source of power as the standby power source, failure of the power source
may be excluded from this criteria.

5.33 Computer-based System

A computer-based system consists of one or more electronic or optical devices which together with their
peripherals and using fixed or programmable logic and memories, processes input data and output signals
for purposes of display, alarm, control or storage. The system is understood to comprise all required hardware,
i.e., microprocessors, monitor (video display unit), keyboard, etc., and data transmission path (data highways).

5.35 Nonvolatile Memory

Memory which does not require power to retain the stored data.

5.37 Computer Monitor (Video Display Unit)

A device where computer information or data is displayed.

5.39 ABS Type Approval Program (2003)

Certification scheme whereby ABS certifies, at the request of the equipment manufacturer, that the specific
equipment conforms to cited standards and to cited ratings which ABS has verified by engineering analysis,
and that an appropriate quality system is in place to manufacture a product of consistent quality. See the
ABS Type Approval Program in Appendix 1-1-A3 of the ABS Rules for Conditions of Classification (Part 1).
The ABS Type Approval Program and the indicated references are available for download from the ABS
website at http://www.eagle.org/absdownloads/index.cfm.

5.41 Integrated Propulsion Machinery

A propulsion machinery having its auxiliaries (fuel oil pumps, cooling water pumps, etc.), necessary for
normal operation driven by the engine, the reduction gear or the propulsion shaft.

7 Required Plans and Data

Plans and data associated with automatic or remote control and monitoring of machinery and systems are
to be submitted for approval in accordance with 4-1-1/7, and are to include the following:

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Part 4 Vessel Systems and Machinery
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Section 1 General 4-7-1

7.1
A list of electrical, pneumatic or hydraulic equipment associated with the particular systems. This is to include
manufacturer’s name, model number, material, ratings, degree of protection, permissible angles of inclination
and location of installation within the vessel.

7.3
A list of all major components installed within the particular equipment (i.e., control console, etc.) and the
data as required in 4-7-1/7.1.

7.5
Certificates or test reports, as appropriate, attesting to the suitability of the particular equipment in compliance
with the environmental criteria set forth in 4-7-2/15 and 4-7-2/17, as applicable. For equipment that have
been already certified by ABS and provided their certification remains valid, the submission of a copy of
pertinent certificate will suffice. See 4-7-2/17.3.

7.7
Plans showing the location of control and monitoring stations, controlled equipment and piping/cable runs, etc.

7.9
Arrangements and details of the control consoles and panels, including plan views and elevation details,
installation details and wiring data (rating, construction standard, insulation type, armored/unarmored/shielded/
non-shielded, temperature rating, flame-retardant properties, etc.).

7.11
A list of all cables connecting equipment associated with the systems. This is to include construction standard,
electrical rating, insulation type, armored/unarmored/shielded/non-shielded, temperature rating, size and
connected load’s power consumption requirements.

7.13
A complete operational description of the automatic or remote control and monitoring systems, including a
list of alarms and displays and functional sketches or description of all special valves, actuator, sensors and
relays.

7.15
A simplified one-line diagram (electrical and piping) of all power and automatic or remote control and
monitoring systems. This is to include power supplies, circuit or piping protection ratings and settings,
cable or pipe sizes and materials, rating of connected loads, etc.

7.17
A schematic diagram of all control, alarm, display and safety systems.

7.19
For computer-based systems, the following is to be included:
i) Overall description and specification of the systems and equipment.
ii) Block diagrams for the computer hardware showing interfacing between the work stations, input/output
(I/O) units, local controllers, traffic controllers, data highways, etc.
iii) Logic flow chart or ladder diagrams.
iv) Description of the alarm system indicating the ways it is acknowledged, displayed on the monitor
or mimic display board, etc.
v) Description of the system redundancy and backup equipment, if any.
vi) Description of the data communication protocol, including anticipated data process response delays.

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vii) Description of the system’s security protocol to prevent unauthorized program changes which may
compromise the integrity of the automatic or remote systems.
viii) Description of the system with regard to the degree of independence or redundancy provided for
the control systems, alarm/display systems and safety systems.
ix) Description of system’s task priorities.
x) Where applicable, description of UPS (uninterruptible power supply) and their capacities, including
system’s power consumption.
xi) Equipment ratings and environmental parameters.

7.21
Installation methods (electrical, pneumatic and hydraulic). This is to include details of cable or pipe runs,
separation of cables of different voltage rating and insulating rating, cable tray laying, deck or bulkhead
penetration, prevention of magnetic interference, etc. See also 4-7-2/15.9.

7.23
A matrix chart for each of the systems indicating the following, as applicable, upon activation of a given alarm
or safety action:
i) Name, device designations and type, and location of alarms.
ii) Preset parameter values, if any.
iii) Automatic tripping and other safety provisions of controlled equipment.
iv) Location of control stations where shutdown, and control and monitoring power supply transfer
devices are fitted.
v) Special remarks, if any.

9 Tests and Surveys

9.1 Installation Tests

Automatic or remote control and monitoring systems are to be subjected to tests witnessed by the Surveyor
during and after installation onboard, as outlined in this Section.

9.3 Periodical Surveys (1998)

The continuance of ACCU or ABCU certification is subject to periodic survey of the automatic or remote
control and monitoring systems installation, as outlined in Chapter 8 of the ABS Rules for Survey After
Construction (Part 7).

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PART Section 2: General Systems Design and Arrangement Requirements

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 2 General Systems Design and Arrangement

Requirements

1 General
Automatic or remote controls and monitoring systems as referenced in this Section include control,
alarm/display and safety systems. For computer-based systems, see 4-7-2/9.

3 Automatic or Remote Control Systems

3.1 Characteristics
Automatic or remote control systems are to be of the fail-safe type and designed to preclude detrimental
mechanical or thermal overloads to the controlled machinery.

3.3 Interlocks
To preclude damage to the controlled machinery, means are to be fitted to disable the starting mechanism
after designated unsuccessful starting attempts. Similarly, controlled machinery or systems fitted with more
than one remote control station are to be provided with interlocking means to preclude simultaneous control
or unauthorized transfer to associated remote stations not in control. However, control units interconnected
with a specific associated remote control station and which are within sight of each other may be accepted
without interlocks.

3.5 Transfer of Control

Transfer of controls from a remote control station under operation to other associated remote stations is to
be possible by a request from the receiving station and acceptance by the station in operation, or vice versa.
See also 4-7-3/7. All control stations are to have indicators showing which station is in control.

3.7 Automatic Controls

Automatic control systems are to be designed to maintain the controlled machinery within pre-set parameters
and to ensure that the machinery operates in the correct sequence and time intervals. Deviation from these
pre-set conditions is to force the sequential controls to a safe sequence stage that will not be detrimental to
the machinery and overall safety of the vessel. Additionally, adequate arrangements are to be included to
disable the automatic control mode and restore manual controls.

3.9 Remote Controls

Remote controls are to be arranged to provide the same degree of safety and operability as those provided
for local controls. Upon a given control input, the controlled device is to respond according to a pre-
established sequence of events and results.

3.11 Local Controls

Remotely operated machinery or systems are to be provided with effective means of independent controls
at or in the proximity to the machinery or systems. Means are to be provided locally to disconnect or override
other associated remote stations or disable automatic control, if any.

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3.13 Suitability of Equipment

Equipment associated with automatic or remote control systems is to be suitable for the intended location.
Control systems are to comply with the requirements contained in 4-7-2/15 and 4-7-2/17.

5 Alarm Systems

5.1 Characteristics
Alarm systems are to be of the self-monitoring type and designed so that a fault in the alarm system is to
cause it to fail to the alarmed condition. Additionally, they are not to react to normal transient conditions or
spurious signals.

5.3 Independence
Alarm systems are to be independent of control and safety systems, except that common sensors will be
acceptable, as permitted in 4-7-2/7.5.

5.5 Visual and Audible Alarm

Alarms are to be both audible and visual and are to be provided at the control stations, as required in this
Section. Alarms are to clearly identify the system and service of the faulted machinery or machinery
components. Visual alarms are to be displayed in a distinguishable manner such that alarms for similar
machinery or systems are grouped together and the colors representing a particular function or condition
remain uniform. Visual alarms are to flash when first activated. Audible alarms associated with machinery
are to be of distinctive tone from other alarms, such as fire-alarm, general alarm, gas detection, etc., and
they are to be of sufficient loudness to attract the attention of duty personnel. For spaces of unusually high
noise levels, a beacon light or similar, installed in a conspicuous place, is to supplement any of the audible
alarms in such spaces. However, red light beacons are only to be used for fire alarms.
A fault in the visual alarm circuits is not to affect the operation of the audible alarm circuits. For computer-
based system, see 4-7-2/9.

5.7 Acknowledgment of Alarms

Alarms are to be acknowledged by manually changing the flashing display of the incoming alarm to a steady
display and by silencing the audible signal. The steady state light display is to remain activated until the fault
condition is rectified. Alarming of other faults that may occur during the acknowledgment process is not to
be suppressed by such action and is to be alarmed and displayed accordingly. The silencing of the audible
alarm from an associated remote control station is not to lead automatically to the silencing of the original
alarm at the centralized control and monitoring station.

5.9 Disconnection and Resumption of Alarm Functions (2010)

Alarm circuits may be temporarily disabled for maintenance purposes or during initial start-up of machinery,
provided that such action is clearly indicated at the associated station in control. For ACCU fire alarm
system, see 4-7-4/29.5.2.

5.11 Summary-alarms
In addition to required alarms to be fitted at the centralized control and monitoring station, visual alarms
may be displayed and alarmed at other associated remote control stations as summary-alarms.

5.13 Built-in Testing

Alarm systems are to be provided with effective means for testing all audible and visual alarms and indicating
lamps without disrupting the normal machinery or system operation. Such means are to be fitted in the
associated remote stations.

5.15 Suitability of Equipment

Equipment associated with automatic or remote alarm systems is to be suitable for the intended location.
Alarm systems are to comply with the requirements contained in 4-7-2/15 and 4-7-2/17.

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7 Safety Systems

7.1 General
Safety systems are to be provided as required in this Section. Considerations will be given to the manual
activation of safety systems, provided that measures are taken, by the inherent design of the system or by
suitable arrangements, to retard the escalation of the abnormal condition and to alert personnel to take the
appropriate action prior to the developing of a dangerous condition.

7.3 Characteristics
Safety systems are to be of the fail-safe type and are to respond automatically to fault conditions that may
endanger the machinery or safety of the crew. Unless otherwise required in this Section or specially approved,
this automatic action is to cause the machinery to take the least drastic action first, as appropriate, by reducing
its normal operating output or switching to a stand-by machinery and last, by stopping it, i.e., disrupting
source of fuel or power supply, etc.

7.5 Independence
Safety systems for different parts of the machinery plant are to be independent of each other. The safety
system intended for the functions specified in 4-7-1/5.25iii) (shutdown) is to be completely independent of
the control and alarms systems so that a failure in these systems will not prevent the safety system from
operating. However, for the functions specified in 4-7-1/5.25i) and 4-7-1/5.25ii), complete independence
of the safety systems from the control and alarm systems is not required.

7.7 Activation
Each safety action is to be alarmed at the associated remote station. When both an alarm and a safety action
are required for a specific failure condition, the alarm is to be activated first.

7.9 Resumption of Operation

Machinery that is stopped as a result of a safety action is not to resume operation unless it is reset manually.

7.11 Override of Safety Provisions

Remote overrides are not to override those safety actions specified in other Sections (i.e., Part 4, Chapter 2
of these Rules and Part 4, Chapters 2, 3 and 4 of the Steel Vessel Rules). For safety action specified in subject
Part 4, Chapter 7, any overrides of safety provisions are to be so arranged that they cannot go unnoticed
and their activation and condition are to be alarmed and indicated at the associated remote station. The
override is to be arranged to preclude inadvertent operation and is not to deactivate alarms associated with
safety provisions. The override mechanism to disconnect safety provisions is to be fitted at the associated
remote station, except that same may be fitted at the centralized control and monitoring station instead.
Overrides fitted on the bridge are to be operable only when in the bridge control mode.

7.13 Suitability of Equipment

Equipment associated with safety systems is to be suitable for the intended location. Safety systems are to
comply with the requirements contained in 4-7-2/15 and 4-7-2/17.

9 Computer-based Systems

9.1 General
Computer-based systems are to be designed so that failure of any of the system’s components will not
cause unsafe operation of the system. Hardware and software serving vital and non-vital systems are to be
arranged to give priority to vital systems.

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9.3 Independence
Control, alarm and safety shutdown system functions are to be arranged such that a single failure or malfunction
of the electronic computer equipment will not affect more than one of these system functions. This is to be
achieved by dedicated equipment for each of these functions within a single system, or by the provision of
back-up equipment, or by other suitable means considered not less effective.

9.5 Visual Display of Alarm

9.5.1 Incoming Signals
In addition to the requirements contained in 4-7-2/5, and when displayed by way of a computer
monitor (video display unit), alarms are to be presented in an identifiable manner, and when displayed,
alarms are to appear in the sequence as the incoming signals are received. Alarming of incoming
fault signals are to automatically appear on the screen to alert the on-duty personnel, regardless of
whether the computer and monitor (video display unit) are in a mode other than the monitoring mode
(i.e., computing or displaying other system’s mimic or schematic diagrams).
9.5.2 Unrectified Alarms
Alarms associated with faults which have not been rectified may be displayed in a summarized
fashion until all of the faults have been dealt with.
9.5.3 Computer Monitor (Video Display Unit)
Displays on the computer monitor (video display unit) are to be clearly visible under ambient lighting
conditions Computer monitors on the navigation bridge are to be provided with dimmers to control
display lighting. Data displayed on computer monitors are to be readable by the operator from the
normal operating position.
9.5.4 Response Delay
The time limit on response delays for safety and alarm displays is not to exceed two seconds.

9.7 Memory Capacity and Response Time

Computer system’s memory is to be of sufficient capacity to handle the operation of all computer programs
(software) as configured in the computer system. The time response for processing and transmitting data is
to be such that undesirable chain of events may not arise as a result of unacceptable data delay or response
time during the computer system’s worst data overload operating condition (multi-tasking mode).

9.9 Data Loss and Corruption

To preclude the possible loss or corruption of data as a result of power disruption, program and associated
memory data considered to be essential for the operation of the specific system is to be stored in non-
volatile memory or a volatile memory with a secure uninterruptible power supply (UPS).

9.11 Power Supply Disruption

The system’s software and hardware is to be designed so that upon restoration of power supply after power
failure, automatic or remote control and monitoring capabilities can immediately be available after the pre-
established computer control access (sign-in) procedure has been completed.

9.13 Parameters and Program Changes

Alteration of parameters that may affect the system’s performance are to be limited to authorization personnel
by means of keyswitch, keycard, password or other approved methods. Similarly, computer program or
system’s configuration changes are to be effected only by authorized personnel.

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11 Supply, Arrangement and System Protection of Automatic or Remote

Control and Monitoring System

11.1 Supply and Arrangement

11.1.1 General
The power distribution to control systems, alarm/display systems (considered as one for the purpose
of this requirement) and safety systems is to be provided with their individual circuits so that a
fault in one of the systems cannot cause loss of the other systems. Their supply status and failure
condition is to be displayed and alarmed at the associated remote propulsion station.
11.1.2 Electrical (2005)
11.1.2(a) Power Source. Power supply requirements provided in 4-7-2/11.1.1, as applicable, are
to be complied with. Electric power for control, monitoring and safety systems is to be fed from
two feeders, one from the main switchboard or other suitable distribution board and the other from
the emergency switchboard or an emergency distribution board. The supply status of these feeders
is to be displayed and the main power supply failure is to be alarmed. The electric power supply to
each of the control, monitoring and safety systems is to be individually monitored. For vessels
whose propulsion machinery spaces are intended for unattended operation (ACCU or ABCU
notation), 4-7-4/11 is to be complied with.
In the event of power supply failure, the propulsion prime movers are to continue to operate at the
last ordered speed and the propellers at the last ordered direction of thrust until local control is in
operation or control power is safely resumed.
11.1.2(b) Power Supply Transfer. The two feeders are to be connected to a transfer switch in the
remote control station. Power supply to controls, monitoring and safety systems may be commonly
connected to the transfer switch. The transfer between the power supplies may be effected by manual
means at the remote control station. For vessels whose propulsion machinery spaces are intended
for unattended operation (ACCU or ABCU notation), 4-7-4/11 is to be complied with.
11.1.3 Hydraulic
The hydraulic pumps for control and monitoring systems are to be fitted in duplicate. The pump
suctions are to be from a reservoir of sufficient capacity to contain all of the fluid when drained
from the system, maintain the fluid level at an effective working height and allow air and foreign
matter to separate out. The pump suctions are to be sized and positioned to prevent cavitation or
starvation of the pump. The hydraulic fluid is to be suitable for its intended operation.
11.1.4 Pneumatic (2010)
Compressed air for control and monitoring systems is to be supplied from at least two air compressors.
The starting air system, where consisting of two air compressors, may be used for this purpose.
The system is to be arranged such that a single failure will not result in the loss of air supply. The
required air pressure is to be automatically maintained.
Means are to be provided to assure that the compressed air for control and monitoring systems is
clean, dry and oil-free to a specification compatible with the control and monitoring equipment. In
this regard, the compressors, cooling equipment, filters and dryers are to be selected and arranged
as necessary to ensure the quality of the air supplied will comply with the standards or criteria
identified by the manufacturers of the pneumatic equipment being installed in the system (e.g.,
max. solid particle size/density, max. dew point, max. oil content, etc.).
Air supplies to safety systems and control systems may be derived from the same source, but are
to be by separate lines incorporating shutoff valves.

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11.3 System Protection

11.3.1 Electrical
Circuits are to be arranged so that a fault in one circuit will not cause maloperation or failure on
another circuit or system. It is to be possible to isolate the faulted circuit. Additionally, systems are
to be protected against accidental reversal of power supply polarities, voltage spikes and harmonic
interference, and in no case is the system’s total harmonic distortion to exceed 5%.
11.3.2 Hydraulic
Pipe systems subject to pressure build-up that may exceed the rated pressure of the pipe and associated
components are to be provided with suitable pressure relief devices fitted on the pump’s discharge
side. Each relief valve is to be capable of relieving not less than full pump flow with a maximum
pressure rise of not more than 10% of the relief valve setting.
11.3.3 Pneumatic
The requirements in 4-7-2/11.3.2 are to be complied with, as applicable.

13 Communications Systems
For communication systems associated with propulsion control stations, the requirements in 4-6-2/15.5.1
are applicable.

15 Equipment Construction, Design and Installation

15.1 General
Equipment associated with remote or automatic control and monitoring systems is to meet compliance with
the requirements contained herein. Deviation from the environmental requirements such as temperature,
humidity and corrosion will be considered for equipment intended for installation in ambient controlled rooms
or enclosures. See also 4-7-2/15.9.2 and 4-7-2/15.9.7. Similarly, where equipment is installed in environments
having parameters other than those as specified in 4-7-2/Table 1 (i.e., cryogenic or highly corrosive
environments, etc.), special consideration corresponding to those of the operating environment will be required.

15.3 Electrical
Equipment is to be constructed of robust, durable and flame-retardant material. It is to be designed to
incorporate the degree of enclosure protection as required in 4-6-3/Table 1. Wiring and cables are to meet
the requirements contained in 4-6-4/7.11.4 and 4-6-4/13, respectively.
Non-current carrying metal parts are to be effectively earthed.

15.5 Hydraulic
Hydraulic pumps, actuators, motors and accessories are to be suitable for the intended service, compatible
with the working fluid and are to be designed to operate safely at full-power conditions. In general, the
hydraulic fluid is to be nonflammable or have a flash point above 157°C (315°F).

15.7 Pneumatic
Air compressors, actuators, motors and accessories are to be suitable for the intended service and have
working and other parts that will not be damaged or rendered ineffective by corrosion.

15.9 Installations
15.9.1 General
The installation of equipment associated with automatic or remote control and monitoring systems
is to be carried out taking into consideration adverse effects that may be introduced by their exposure
to unintended temperatures, weather, vibration conditions, falling objects or liquid, electromagnetic
interference, high voltage systems, electric noise, etc. Additionally, the installation is to facilitate
the checking, adjustment and replacement of components, including filters and sensing devices,
without disrupting the normal operation of the system, as far as practicable.

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15.9.2 Ranges in Ambient Temperatures

For the selection and installation of equipment associated with control and monitoring systems, a
temperature range of 5°C (41°F) to 55°C (131°F) is to be considered for machinery space, control
rooms, accommodations and navigation bridge. When equipment is located inside panels or cubicles,
consideration is to be given to the temperature rise inside those panels due to the dissipation of
heat from its own components. See also 4-7-2/Table 1, Note 1.
Where compliance with the above temperature ranges cannot be met, consideration will be given
to the installation of equipment per 4-7-2/15.9.7.
15.9.3 Electromagnetic and Conducted Interference
In general, the installation of equipment associated with automatic or remote control and monitoring
systems in areas of unusual electromagnetic systems in areas of unusual electromagnetic sources
is to be avoided. Where the values per 4-7-2/Table 1 may be exceeded, appropriate measures are
to be implemented to reduce the effects of electromagnetic and conducted interference. To avoid
electromagnetic noise caused by circulating currents, the conductive shield and cable armor is to
be earthed only at one end of the cable. Description of the preventive measures to be followed is
to be submitted for review.
15.9.4 Shielded Cables
To avoid possible signal interference, cables for automatic or remote control and monitoring systems
occupying the same cable tray, trunk or conduit with power cables are to be of the shielded type.
15.9.5 Electrical Grounding
Automatic or remote control and monitoring systems are not to have common earth conductors
with systems of higher voltage level.
15.9.6 Condensation
Electrical equipment liable to be exposed to ambient temperature fluctuations is to be provided
with means to prevent accumulation of moisture inside of the component’s enclosure (i.e., by the
provisions of space heaters that automatically energize upon shutdown or disconnection of the
electrical component).
15.9.7 Cold Environment
Electrical equipment which may be adversely affected by the exposure to temperatures lower than
those for which they are designed are to be provided with suitable heating arrangements so that
they may be readily operated when needed. See 4-7-2/15.9.2.
15.9.8 Protection Against Falling Liquids or Leakage of Fluid Medium
Electrical equipment is not to be installed in the same compartment or cabinet containing equipment
or pipes carrying water, oil or steam unless effective measures are taken in order to protect the
electrical equipment from possible fluid leakage (i.e., welded connections, physical isolation together
with suitable draining arrangements, etc.).
15.9.9 Measuring and Sensing Devices
The installation of measuring and sensing elements is to permit their easy access for functional testing
or replacement.
15.9.10 Marking
All units, controllers, actuators, displays, terminal strips, cable and test points, etc. are to be clearly
and permanently marked. Their systems and system’s functions are to be included so that they can
be easily identified in associated drawings and instrument lists.

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17 Equipment/Components Qualifications and Trials

17.1 Equipment/Components Qualifications

The manufacturers and assemblers of automatic or remote control and monitoring equipment/ components
associated with main propulsion engines are to provide documented evidence showing that the equipment/
components have been tested individually or by acceptable sampling to establish their suitability for the
intended service.

17.3 Type Approval of Automatic or Remote Control and Monitoring Equipment

Equipment that meets the requirements contained in this subsection or 4-7-4/3 is eligible to be certified
under the ABS Type Approval Program upon formal request by the equipment manufacturer. See also
4-7-1/5.39 and 4-7-1/7.5.

17.5 Trials
Automatic or remote control and monitoring systems and associated equipment are to be tested in the presence
of the Surveyor, under normal operating conditions and for the period that the Surveyor may deem necessary
or otherwise specified in other Subsections.

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TABLE 1
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note 7]
1. Power supply - AC Supply
variations
Combination Voltage Frequency
(a) electric variation variation
permanent permanent
(%) (%)
1 +6 +5
2 +6 –5
3 – 10 –5
4 – 10 +5

Combination Voltage Frequency

transient transient
1.5 s (%) 5 s (%)
5 + 20 + 10
6 – 20 – 10

DC Supply
Voltage tolerance continuous ± 10%
Voltage cyclic variation 5%
Voltage ripple 10 %

Electric battery supply:

+ 30% to – 25% for equipment connected
to charging battery or as determined by the
charging / discharging characteristics,
including ripple voltage from the charging
device;
+ 20% to – 25% for equipment not
connected to the battery during charging
2 Power supply - Pressure: ± 20%
variations Duration: 15 minutes
(Continued)
(b) Pneumatic
and hydraulic
3. Dry heat IEC Publication Temperature: 55°C (131°F) ± 2°C (3.6°F) Equipment operating during
60068-2-2 Duration: 16 hours conditioning and testing;
Or functional test during the last hour
Temperature: 70°C (158°F) ± 2°C (3.6°F) at the test temperature;
Duration: 2 hours
[See Note 1]

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TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note 7]
4. Damp heat IEC Publication Temperature: 55°C (131°F) Measurement of insulation
60068-2-30 - Test Humidity: 95% resistance before test;
Db Equipment operating during the
Duration: 2 cycles 2 × (12 + 12 hours)
complete first cycle and switched
off during second cycle, except
for functional test;
Functional test during the first
two hours of the first cycle at the
test temperature and during the
last two hours of the second cycle
at the test temperature;
Recovery at standard atmosphere
conditions;
Insulation resistance
measurements and performance
test.
5. Vibration IEC Publication 2.0 (+3/-0) Hz to 13.2 Hz – amplitude Duration: 90 minutes at 30 Hz in
(2008) 60068-2-6, Test Fc ± 1 mm (0.039 in) case of no resonance conditions;
13.2 Hz to 100 Hz – acceleration ± 0.7 g Duration: 90 minutes for each
For severe vibration conditions, e.g., on resonance frequency at which
diesel engines, air compressors, etc.: Q ≥ 2 is recorded;
2.0 Hz to 25 Hz – amplitude ± 1.6 mm During the vibration test,
(0.063 in) functional tests are to be carried
out;
25.0 Hz to 100 Hz – acceleration ± 4.0 g
Tests to be carried out in three
mutually perpendicular planes;
Note: It is recommended as guidance
More severe conditions may exist, for that Q does not exceed 5;
example, on exhaust manifolds of diesel Where sweep test is to be carried
engines, especially for medium and high speed
out instead of the discrete
engines.
frequency test and a number of
Values may be required to be in these cases resonant frequencies are detected
40 Hz to 2000 Hz – acceleration ± 10.0 g at close to each other duration of the
600°C duration 90 min. test is to be 120 min. Sweep over
a restricted frequency range
between 0.8 and 1.2 times the
critical frequencies can be used
where appropriate. Note: Critical
frequency is a frequency at which
the equipment being tested may
exhibit:
• malfunction and/or
performance deterioration
• mechanical resonances
and/or other response effects
occur, for example, chatter

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TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note 7]
6. Inclination IEC Publication Static 22.5° a) Inclined at an angle of at
60092-504 least 22.5° to the vertical;
b) Inclined to at an angle of at
least 22.5° on the other side
of the vertical and in the
same plane as in (a);
c) Inclined to at an angle of at
least 22.5° to the vertical
and in plane at right angles
to that used in (a);
d) Inclined to at an angle of at
least 22.5° on the other side
of the vertical and in the
same plane as in (c)
Note: The duration of testing in
each position should be sufficient
to fully evaluate the behavior of
the equipment.
Dynamic 22.5° Using the directions defined in a)
to d) above, the equipment is to
be rolled to an angle of 22.5° each
side of the vertical with a period
of 10 seconds.
The test in each direction is to be
carried out for not less than
15 minutes
Note: These inclination tests are
normally not required for
equipment with no moving parts.
7. Insulation - Rated Test Min. Insulation Insulation resistance test is to be
resistance supply voltage (V) Resistence carried out before and after: damp
(2008) voltage heat test, cold test, salt mist test,
Before After
(V) and high voltage test;
test test
• between all phases and earth;
(MΩ) (MΩ)
• and where appropriate,
Un ≤ 65 2 × Un 10 1.0
between the phases.
(min. 24 V)
Un is the rated (nominal) voltage.
Un > 65 500 100 10 Note: Certain components, e.g.,
for EMC protection, may be
required to be disconnected for
this test. For high voltage
equipment, reference is made to
4-6-5/1.
8. High voltage - Rated voltage Test voltage [A.C. voltage Separate circuits are to be tested
Un (V) 50 or 60 Hz] (V) against each other and all circuits
Up to 65 2 × Un + 500 connected with each other tested
against earth;
66 to 250 1500
Printed circuits with electronic
251 to 500 2000 components may be removed
501 to 690 2500 during the test;
Period of application of the test
voltage: one minute

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Section 2 General Systems Design and Arrangement Requirements 4-7-2

TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note 7]
9. Cold (2008) IEC Publication Temperature: +5°C (41°F) ± 3°C (5.4°F) Initial measurement of insulation
60068-2-1 Duration: two hours resistance;
Or Equipment not operating during
Temperature: –25°C (–13°F) ± 3°C (5.4°F) conditioning and testing, except
Duration: two hours for functional test;
[See Note 2] Functional test during the last
hour at the test temperature;
Insulation resistance
measurement and the functional
test after recovery
10. Salt mist IEC Publication Four spraying periods with a storage of Initial measurement of insulation
60068-2-52 Test Kb seven days after each. resistance and initial functional
test;
Equipment not operating during
conditioning of the test specimen;
Functional test on the 7th day of
each storage period;
Insulation resistance
measurement and performance
test: four to six hours after
recovery [See Note 3]
11. Electrostatic IEC Publication Contact discharge: 6 kV To simulate electrostatic
discharge 61000-4-2 Air discharge: 8 kV discharge as may occur when
persons touch the appliance;
Interval between single discharges: 1 sec.
The test is to be confined to the
Number of pulses: 10 per polarity points and surfaces that can
According to level 3 severity standard normally be reached by the
operator;
Performance Criterion B
[See Note 4].
12. Electro- IEC Publication Frequency range: 80 MHz to 2 GHz To simulate electromagnetic
magnetic field 61000-4-3 Modulation*: 80% AM at 1000 Hz fields radiated by different
transmitters;
Field strength: 10 V/m
The test is to be confined to the
appliances exposed to direct
Frequency sweep rate: ≤ 1.5 × 10-3 radiation by transmitters at their
decades/s (or 1% / 3 sec) place of installation.
According to level 3 severity standard. Performance criterion A [See
Note 5]
* If for tests of equipment, an
input signal with a
modulation frequency of
1000 Hz is necessary, a
modulation frequency of
400 Hz may be chosen.

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Part 4 Vessel Systems and Machinery
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Section 2 General Systems Design and Arrangement Requirements 4-7-2

TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note 7]
13 Conducted AC: To simulate distortions in the
Low Frequency range: rated frequency to 200th power supply system generated,
Frequency harmonic; for instance, by electronic
(2008) consumers and coupled in as
Test voltage (r.m.s.): 10% of supply to 15th harmonics;
harmonic reducing to 1% at 100th harmonic
and maintain this level to the 200th harmonic, Performance criterion A
minimum 3 V (r.m.s.), maximum 2 W [See Note 5]
See 4-7-2/Figure 1 for test set-up.
DC:
Frequency range: 50 Hz – 10 kHz;
Test voltage (rms): 10% of supply,
maximum 2 W
14. Conducted IEC Publication AC, DC, I/O ports and signal/control Equipment design and the choice
Radio 61000-4-6 lines: of materials are to simulate
Frequency Frequency range: 150 kHz – 80 MHz electromagnetic fields coupled as
high frequency into the test
Amplitude: 3 V r.m.s. [See Note 6] specimen via the connecting lines.
Modulation ** : 80% AM at 1000 Hz Performance criterion A [See
Frequency sweep range: ≤ 1.5 × 10-3 Note 5].
decades/sec. (or 1% / 3 sec.) ** If for tests of equipment, an
According to level 2 severity standard input signal with a
modulation frequency of
1000 Hz is necessary, a
modulation frequency of
400 Hz should be chosen.
15. Burst/Fast IEC Publication Single pulse time: 5 ns (between 10% and Arcs generated when actuating
Transients 61000-4-4 90% value) electrical contacts;
Single pulse width: 50 ns (50% value) Interface effect occurring on the
Amplitude (peak): 2 kV line on power power supply, as well as at the
supply port/earth; external wiring of the test
1 kV on I/O data control and specimen;
communication ports (coupling clamp); Performance criterion B
Pulse period: 300 ms; [See Note 4].
Burst duration: 15 ms;
Duration/polarity: 5 min
According to level 3 severity standard.
16. Surge Voltage IEC Publication Pulse rise time: 1.2 μVs (between 10% and Interference generated, for
61000-4-5 90% value) instance, by switching “ON” or
Pulse width: 50 μVs (50% value) “OFF” high power inductive
Amplitude (peak): 1 kV line/earth; consumers;
0.5 kV line/line Test procedure in accordance
with figure 10 of the standard for
Repetition rate: ≥ 1 pulse/min equipment where power and
Number of pulses: 5 per polarity signal lines are identical;
Application: continuous Performance criterion B
According to level 2 severity standard. [See Note 4].

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Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 2 General Systems Design and Arrangement Requirements 4-7-2

TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[SEE NOTE 7]
17. Radiated CISPR 16-1, 16-2 For equipment installed in the bridge Procedure in accordance with the
Emission and deck zone. standard, but distance 3 m (10 ft)
Frequency range: Limits: between equipment and antenna
0.15 – 0.3 MHz 80 – 52 dBμV/m
0.3 – 30 MHz 50 – 34 dBμV/m
30 – 2000 MHz 54 dBμV/m
except for:
156 – 165 MHz 24 dBμV/m
For equipment installed in the general
power distribution zone.
Frequency range: Limits:
0.15 – 30 MHz 80 – 50 dBμV/m
30 – 100 MHz 60 – 54 dBμV/m
100 – 2000 MHz 54 dBμV/m
except for:
156 – 165 MHz 24 dBμV/m
18. Conducted CISPR 16-1, 16-2 For equipment installed in the bridge
Emission and deck zone.
Frequency range: Limits:
10 – 150kHz 96- 50 dBμV
150 – 350 kHz 60- 50 dBμV
350 kHz – 30 MHz 50 dBμV
For equipment installed in the general
power distribution zone.
Frequency range: Limits:
10 – 150 kHz 120- 69 dBμV
150 – 500 kHz 79 dBμV
0.5 – 30 MHz 73 dBμV
19. Flame IEC Publication Flame application: 5 times 15 sec each. The burnt out or damaged part of
retardant 60092-101 or Interval between each application: 15 sec. the specimen by not more than
(2008) IEC Publication or 1 time 30 sec. 60 mm long.
60695-11-5 Test criteria based upon application. No flame, no incandescence or in the
The test is performed with the Equipment event of a flame or incandescence
Under Test (EUT) or housing of the EUT being present, it shall extinguish
applying needle-flame test method. itself within 30 sec. of the removal
of the needle flame without full
combustion of the test specimen.
Any dripping material shall
extinguish itself in such a way as
not to ignite a wrapping tissue.
The drip height is 200 mm ± 5 mm.

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Section 2 General Systems Design and Arrangement Requirements 4-7-2

TABLE 1 (continued)
Type Tests for Control, Monitoring and Safety Equipment (2008)
Notes:
1 Equipment to be mounted in consoles, housing, etc., together with other equipment is to be tested with 70°C (158°F).
2 For equipment installed in non-weather protected locations or cold locations, test is to be carried out at –25°C (–13°F).
3 Salt mist test is to be carried out for equipment installed in weather exposed areas.
4 Performance criterion B (for transient phenomena): The equipment under test is to continue to operate as intended
after the tests. No degradation of performance or loss of function is allowed, as defined in the technical specification
published by the manufacturer. During the test, degradation or loss of function or performance which is self-recoverable
is, however, allowed but no change of actual operating state or stored data is allowed.
5 Performance criterion A (for continuous phenomena): The equipment under test is to continue to operate as intended
during and after test. No degradation of performance or loss is allowed, as defined in relevant equipment standard
and the technical specification published by the manufacturer.
6 For equipment installed on the bridge and deck zone, the test levels are to be increased to 10 V rms for spot frequencies,
in accordance with IEC 60945 at 2, 3, 4, 6.2, 8.2, 12.6, 16.5, 18.8, 22, 25 MHz.
7 Alternative equivalent testing procedures may be accepted, provided the requirements in the other columns are complied
with.

FIGURE 1
Test Set-up for Conducted Low Frequency Test
(See Test No. 13 of 4-7-2/Table 1) (2008)

Generator

Power Supply

AC DC

L1 (+)
V Voltmeter *)

EUT N (−)

PE

*) Decoupling (optional)

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PART Section 3: Automatic or Remote Propulsion Control and Monitoring Systems

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 3 Automatic or Remote Propulsion Control and

Monitoring Systems

1 General
The requirements contained in this section are applicable to propulsion machinery/systems intended for
automatic operation or operation from a remote propulsion control station. Except as noted herein, the
requirements in Sections 4-7-1 and 4-7-2, as applicable, are to be complied with.

3 Propulsion Control Capability (1 July 1998)

Vessels with the keel laid or in similar stage of construction on or after 1 July 1998 are to meet the following
requirements. Under all sailing conditions, including maneuvering, the speed, direction of thrust and, where
applicable, the pitch of the propeller, is to be fully controllable from the remote propulsion control station.
The remote control is to be performed by a single control device for each independent propeller, with
automatic performance of all associated services, including, where necessary, means of preventing overload
of the propulsion machinery.

5 Propulsion Control Orders and Indicators (1 July 1998)

Vessels with the keel laid or in similar stage of construction on or after 1 July 1998 are to meet the following
requirements. Propulsion machinery orders from the navigation bridge are to be indicated in the main machinery
control room and at the maneuvering platform. See 4-6-2/15. The navigation bridge, main machinery
control room and maneuvering platform is to be fitted with indication of the following:
i) Propeller speed and direction of rotation in the case of fixed pitch propeller, or
ii) Propeller speed and pitch position in the case of controllable propellers.

7 Propulsion Control Command

The remote propulsion control stations in the propulsion machinery space, as described in 4-7-3/5, are to
be capable of assuming control at all times and to block orders from other associated remote control stations,
if fitted. Considerations will be given to cases where, due to the intended vessel’s service and operational
requirements, it may be necessary for other associated stations to have override controls over the remote
propulsion control stations in the propulsion-machinery space. See 4-7-2/3.3 and 4-7-2/3.5.

9 Propulsion Control Settings Deviation

Control transfer arrangements are to include means to prevent the propelling thrust from altering significantly
when transferring control from one propulsion control station to another.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 3 Automatic or Remote Propulsion Control and Monitoring Systems 4-7-3

11 Propulsion Control Power Failure

In the event of power failure of the propulsion control system, the propulsion units are to continue to
operate at the last ordered speed and direction of thrust of the propellers until local control is in operation
or control power is safely resumed, However, considerations will be given to special cases, where due to
the intended vessel’s propulsion design and operational requirements, it may be necessary to automatically
reduce the propulsion engine speed and reset the propeller pitch to zero upon control power failure.

13 Propulsion Starting

13.1
An alarm is to be provided in the propulsion-machinery space and at any propulsion control station fitted
outside of the propulsion-machinery space to indicate a low level starting condition which is to be set at a
level to permit further main engine starting operations. Where automatic starting of the propulsion machinery
is fitted, the number of consecutive attempts to automatically start an engine is to be limited in order to
safeguard sufficient capacity for local starting from the propulsion-machinery space. See also 4-2-1/13.

13.3
Propulsion machinery control system is to be designed so that it will automatically inhibit the starting of
the propulsion machinery where conditions exist which may damage the propulsion machinery, i.e., shaft
turning gear engaged, insufficient lubricating oil pressure, etc.

15 Remote Override of Safety Provisions

Remote override of safety provisions is not permitted for the following:

15.1
Shutdown of propulsion gas turbines upon failure or loss of the oil lubricating system. See 4-6-5/5.3.3 of
the Steel Vessel Rules.

15.3
Shutdown of prime-movers for propulsion and ship’s service diesel-generators upon activation of overspend
mechanism. See 4-6-4/3.19 of these Rules and 4-2-1/7.3 of the Steel Vessel Rules. However, considerations
will be given to specific cases where due to the vessel’s design and operational requirements, it may be
necessary to momentarily override the propulsion machinery over the overspeed automatic shutdown.

15.5
Shutdown of prime-movers upon failure or loss of oil lubricating system to forced-lubricated propulsion or
ship’s service diesel-generators. See 4-6-4/3.15.

17 Critical Speeds
Adequate means are to be provided at the remote propulsion control station to alert the station operator of
prolonged operation of the propulsion drives within barred speed ranges.

19 Emergency Shutdown
The propulsion machinery is to be provided with an emergency stopping device on the navigation bridge
which is to be independent of the navigation bridge control system.

21 Automatic Shutdown Alarm

If the control system automatically shuts down the main propulsion machinery for any reason, this is to be
alarmed at the remote propulsion control station.

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Section 3 Automatic or Remote Propulsion Control and Monitoring Systems 4-7-3

23 Automatic Propulsion Control System

23.1 Integrity and Manual Control Functions

The automatic propulsion control system is to be designed and arranged so that a failure in the system is
not to compromise the integrity nor the manual operation of the propulsion machinery.

23.3 Threshold Warning for Safety System Activations (1 July 2004)

Where the propulsion machinery is capable of remote control from the navigation bridge, regardless of
manned or unmanned machinery space, automation systems are to be designed in a manner such that a
threshold warning of impending or imminent slowdown or shutdown of the propulsion system is given to
the officer in charge of the navigational watch in time to assess navigational circumstances in an emergency.
In particular, the systems are to control, monitor, report, alert and take safety action to slow down or shut
down propulsion while providing the officer in charge of the navigational watch an opportunity to
manually intervene (override), except for those cases where manual intervention will result in total failure
of the engine and/or propulsion equipment within a short time, for example, in the case of over speed.

25 Controls and Instrumentation on Remote Propulsion Control Stations

Remote propulsion control stations fitted in vessels having the propulsion-machinery space manned are to
be provided with the controls, alarms and displays as listed in 4-7-4/Table 2, as a minimum. This requirement
is not applicable to portable propulsion control units interconnected with and arranged for operation within
sight from the associated remote propulsion control station.

27 Trials

27.1 Automatic/Remote Control

The ability to effectively control the propulsion from the remote propulsion control station is to be
demonstrated to the satisfaction of the Surveyor during sea trials or at dockside. These trials are to include
propulsion control transfer, propulsion starting, verification of propulsion control responses, propulsion
control power failure and actuation of propulsion emergency stop device.

27.3 Independent Manual Control

Independent manual control of the propulsion machinery is to be demonstrated during the tests or trials to
the satisfaction of the Surveyor. This is to include demonstration of independent manual control through
the full maneuvering range and transfer from automatic control.

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PART Section 4: Vessels Classed with ACCU Notation

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 4 Vessels Classed with ACCU Notation

1 General
Vessels having the means to control and monitor the propulsion machinery and propulsion-machinery
space from the navigation bridge and from a centralized control and monitoring station installed within, or
adjacent to, a periodically unattended propulsion-machinery space are to comply with the requirements
contained in this subsection. Except as noted herein, the requirements in Sections 4-7-1 through 4-7-3, as
applicable, are to be complied with. The requirements in this subsection cover the operation required for
propulsion machinery start-up, safe sailing during open sea and maneuvering conditions, and do not cover
operations after anchoring or mooring.

3 Equipment (2003)
Equipment associated with the remote or automatic control and monitoring of the propulsion machinery is
to comply with the following requirements.

3.1 Application
Requirements of 4-7-4/3 apply to equipment that are components of the control, monitoring and safety
systems of propulsion machinery, propulsion boilers, vital auxiliary pumps and the electrical power
generating plant, including its prime mover, for vessels to be assigned with ABCU or ACCU notation.

3.3 Environmental Test Conditions

Control, safety and monitoring equipment is to be designed such that it will successfully withstand the test
conditions stipulated in 4-7-2/Table 1, as applicable.
Upon request by the manufacturer, equipment designed to environmental conditions in excess of those in
4-7-2/Table 1 may be tested to such conditions and certified accordingly.

3.5 Environmentally Controlled Space

Where equipment is designed to operate only in a temperature regulated environment, the temperature
regulating system (such as air-conditioner) is to be backed up by a stand-by unit. Failure of the system is to
be alarmed.

3.7 Electric and Electronic Equipment

Electric and electronic equipment that are components of control, safety and monitoring systems are to be
designed and constructed in accordance with the provisions of 4-7-2/15.

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Section 4 Vessels Classed with ACCU Notation 4-7-4

3.9 Equipment Tests

3.9.1 Prototype Environmental Testing
The following tests are to be carried out as a prototype testing in the presence of the Surveyor:
i) Power supply variation test (item 1 in 4-7-2/Table 1)
ii) Vibration test (item 5 in 4-7-2/Table 1)
iii) Inclination test (item 6 in 4-7-2/Table 1)
Other prototype environmental tests specified in 4-7-2/Table 1 are to be conducted by the
manufacturers. Acceptance will be based on review of the manufacturer’s certified test reports by
ABS. Omission of certain tests may be considered, taking into consideration the location of
installation, functionality, contained devices, etc. of the equipment.
In general, field sensors (e.g., pressure transmitters) and field devices (e.g., solenoid valves), circuit
breakers and cables may be exempted from the tests specified in 4-7-2/Table 1.
For computer-based systems, the equipment to be tested includes microprocessors, storage devices,
power supply units, signal conditioners, analog/digital converters, computer monitors (visual display
units), keyboards, etc., but may exclude printer, data recording or logging device not required in
this section.
3.9.2 Production Unit Certification
After assembled to a complete assembly unit or subassembly unit, each production unit of equipment
used in control, monitoring and safety systems is to be tested at the manufacturer’s shop in the
presence of the Surveyor to verify the tests in 4-7-4/Table 1.
3.9.3 Type Approval Program
At the request of the manufacturer, equipment, subassemblies or complete assemblies of control,
monitoring and safety systems may be considered for Type Approval in accordance with the provisions
of 1-1-A3/5.3 (AQS)/(RQS) or 1-1-A3/5.5 (PQA) of the ABS Rules for Conditions of Classification
(Part 1). Where qualified, they may be listed on the ABS website as Type Approved Products.
Those products type-approved under 1-1-A3/5.3 (RQS) of the ABS Rules for Conditions of
Classification (Part 1) will be acceptable, subject to renewal and updating of the certificates, for
the purposes of Part 4, Chapter 7 without the need for the Surveyor’s attendance at the production
tests and inspections specified in 4-7-4/3.9.2. Production unit certification in such instances will
be carried out as described in 1-1-A3/5.7.1(a) of the above-referenced Part 1.
For the updating or renewal of type approval, please refer to 1-1-A3/5.7.2 and 1-1-A3/5.7.4 of the
ABS Rules for Conditions of Classification (Part 1).

5 Automatic Propulsion Controls

Effective control of the propulsion machinery from the navigation bridge is to be performed with automatic
performance of all associated functions, including, where necessary, means of preventing overload of the
propulsion machinery. The required automatic control means to operate the propulsion machinery are to be
capable of meeting load demands from standby to full system rated load under all operating conditions
without the need for manual adjustment or manipulation.

7 Station in Navigation Bridge

The navigation bridge propulsion control station is to include the following: controls, displays and alarms
(see also 4-7-4/Table 2).
i) The means to alarm excessive rise of water in the propulsion-machinery space bilges.
ii) A summary-alarm for the propulsion and its associated machinery. Any of the alarm conditions as
listed in 4-7-4/Table 4A through 4-7-4/Table 7 is to activate the summary-alarm.
iii) Means of remote starting of any one of the main fire pumps unless the fire main is permanently
pressurized.

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Section 4 Vessels Classed with ACCU Notation 4-7-4

9 Centralized Control and Monitoring Station

The centralized control and monitoring station is to include adequate controls, displays and alarms needed
to maintain normal and safe operation of the propulsion machinery and monitor associated ship’s service
systems, electrical power generating machinery and propulsion-machinery space. The installed control and
monitoring system is to provide the same degree of control as if the propulsion-machinery space was manned.
See 4-7-4/Table 3 through 4-7-4/Table 7 for required controls, alarms and displays to be fitted at such station.

11 Power Supply for Control and Monitoring Systems

11.1 General
The power supply arrangement is to be in accordance with 4-7-2/11.1.1. In addition, an emergency feeder
or pipe is to be provided for control systems, display/ alarm systems and safety systems.

11.3 Electrical
The emergency feeder as well as the main supply feeder for control systems, alarm/display systems and safety
are to be connected to the emergency switchboard and main switchboard (distribution boards), respectively,
and are to be provided with short-circuit protection at such boards. Their supply status are to be displayed
at the remote propulsion stations.

11.5 Power Supply Transfer

Transfer of power supply for the systems is to be effected automatically. The power supply transfer device
(switch or valve) is to be arranged for manual operation.

13 Continuity of Power

13.1 General
Provision is to be made for automatic starting and connecting to the main switchboard of a standby generator of
sufficient capacity to permit propulsion and steering and to ensure the safety of the vessel with automatic
restarting of the essential auxiliaries, including, where necessary, sequential operations. This standby electric
power is to be available in no more than 45 seconds.

13.3 Reduced Power

To satisfy 4-7-4/13.1, the operation of propulsion machinery and vital services may be at reduced power.

15 Automatic Transferring of Vital Auxiliary Pumps (2007)

The means for the automatic starting and transferring of required standby vital auxiliary pumps associated
with propulsion are to be provided. The automatic starting and transferring of vital auxiliary pumps, where
fitted is to be alarmed at the centralized control and monitoring station. The centralized control and monitoring
station is to be provided with means to remotely start and stop vital auxiliary pumps associated with the
following machinery/systems:
i) Propulsion Machinery
ii) Electrical Power Generating Machinery
iii) Controllable Pitch Propellers (C.P.P)
iv) Fuel Oil Transfer or Service System. This is applicable to pumps associated with settling and daily
service tanks.

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Section 4 Vessels Classed with ACCU Notation 4-7-4

17 Propulsion Gas Turbines (1999)

The centralized control and monitoring station is to be provided with the safety provisions, alarms and
displays as listed in 4-7-4/Table 5. Special consideration may be given for vessels in restricted service.
See 4-2-3/7.7 of the Steel Vessel Rules.

19 Propulsion Diesel Engines

19.1 Lubricating Oil

In the event of loss of lubricating oil, there is to be an automatic shutdown of the main engine.

19.3 Overspeed
An overspeed condition is to cause the automatic shutdown of the main engine.

19.5 Controls and Instrumentation

The centralized control and monitoring station is to be provided with the safety provisions, alarms and
displays as listed in 4-7-4/Table 4A and 4-7-4/Table 4B.

21 Electric Propulsion
For electric propulsion driven vessels, in order to prevent nuisance tripping of the main generator circuit
breakers, a power management system is to be provided and arranged so that when the power requirement
for the propulsion motors exceeds the on-line generating capacity, the power management system is to
automatically take a corrective action, such as reduction of power, shedding of non-essential loads, etc.
The centralized control and monitoring station is to be provided with the alarms and displays as listed in
4-7-4/Table 6.

23 Electrical Power Generating Machinery

The centralized control and monitoring station is to be provided with the alarms and displays as listed in
4-7-4/Table 7.

25 Fuel Oil Settling and Daily Service Tanks

25.1 General
Low level conditions of fuel oil settling and daily service tanks are to be alarmed at the centralized control
and monitoring station. Additionally, adequate interlock means to prevent tank overpressurization or overflow
spillages are to be provided.

25.3 Automatic Filling

The fuel oil settling or daily service tanks are to be of a capacity sufficient for at least eight hours operation
at normal power. The arrangements are to include high level alarm together with automatic filling pump
shutdown and automatic pump start-up at a predetermined low level, in addition to the arrangements per
4-7-4/25.1.

25.5 Heating Arrangements

See 4-7-4/29.3.3.

27 Propulsion and Associated Machinery Start-up

Starting of the propulsion and associated machinery or preparing the engines for sea may be performed
manually, but if done automatically, this is to be programmed that the propulsion machinery cannot be
started until all engine auxiliaries are functioning correctly.

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Part 4 Vessel Systems and Machinery
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Section 4 Vessels Classed with ACCU Notation 4-7-4

29 Arrangement and Monitoring of Machinery Space

29.1 Bilges
29.1.1 General
The propulsion-machinery space is to be provided with a bilge water-level system to detect excessive
water influx or rise in the propulsion-machinery space bilges at the various angles of vessel’s heel
and trim. The bilge wells are to be large enough to accommodate the normal drainage. Excessive
water influx or rise in the bilge wells is to be alarmed at the centralized control and monitoring
station. See also 4-7-4/Table 2 and 4-7-4/Table 3 for alarms and displays.
29.1.2 Excessive Automatic Starting of Bilge Pumps
Means are to be provided to indicate at the centralized control and monitoring station when the
influx of liquid is greater than the pump capacity or when the pump is operating more frequently
than would normally be expected. Additionally, special attention is to be given to oil pollution
prevention requirements.

29.3 Fire Prevention

To minimize the outbreak of fire, the following is to be provided:
29.3.1
In high pressure fuel-oil piping (see 4-2-1/7.3 of these Rules and 4-6-5/3.7.1 of the Steel Vessel
Rules), an oil leakage condition is to be alarmed at the centralized control and monitoring station.
29.3.2
Drip trays for collecting oil, as required in 4-4-1/9.23, are to be of suitable height and provided
with suitable drainage to a collecting tank incorporating a high level alarm audible at the centralized
control and monitoring station.
29.3.3
Where heaters are provided in fuel systems, the required alarms in 4-4-4/1.5 are to be located at
the centralized control and monitoring station.
29.3.4
Fuel oil heaters, purifiers, pumps and filters are to be shielded or grouped in a special room or
location ventilated by suction.

29.5 Fire Detection and Alarm (2010)

29.5.1 General
The propulsion-machinery space is to be provided with a fixed fire detection and alarm system
complying with Regulation II-2/14 of SOLAS 1974, as amended. This fixed fire detection and
alarm system may be combined with other fire detection and alarm systems required onboard the
vessel. The fire control panel is to be located on the navigation bridge or in the fire fighting station.
If located in the fire fighting station, a repeater panel is to be fitted on the navigation bridge. Propulsion
machinery space fire is to be alarmed in the centralized control station.
29.5.2 Temporarily Disconnecting Alarms
A fire detector loop or detector(s) covering the unattended machinery space may be temporarily
disabled, for example, for maintenance purposes and such action is to be clearly indicated at the
fire control panel and at the centralized control station described in 4-7-4/29.5.1. Disabled loop or
detectors are to be reactivated automatically after a preset time period.

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Section 4 Vessels Classed with ACCU Notation 4-7-4

31 Monitoring Station in Engineers’ Accommodation

The following is applicable to vessels fitted with engineers’ accommodations.

31.1 General (2006)

At least one alarm monitoring station is to be provided in the engineers’ public spaces, such as the officers’
lounge or officers’ mess room. Where the engineer on-duty is assigned to work in a specific space, such as
the ship’s office or engineers’ office, then such a space is also to be provided with an alarm monitoring station.
Each such station is to be provided with alarms for fire, high bilge-water level in the propulsion-machinery
space, and summary-alarms for the propulsion and its associated machinery Any of the alarm conditions as
listed in 4-7-4/Table 4A through 4-7-4/Table 7, as applicable, are to activate the specific machinery
summary-alarm. Additionally, alarm monitoring stations through a selector switch are to be provided in
each individual engineer’s stateroom and arranged so that at least one alarm monitoring station is active at
all times. Selective switching is not to be provided for the fire alarms. The fire alarm is to be separate and
distinct from the alarms of any other systems. Fire, high bilge-water level and the specific machinery
summary-alarms are to be audible in the engineers’ public spaces and staterooms until manually silenced at
the centralized control and monitoring station in the propulsion-machinery space.

31.3 Alternative Arrangement

The arrangements in 4-7-4/31.1 may be modified to permit the audible machinery summary-alarm and
high bilge water level alarm to be silenced locally at the alarm monitoring stations in the engineers’ public
spaces and staterooms, provided the associated visual alarm is not extinguished. Also, the arrangements are
to be such that if the audible alarm is not also silenced manually at the centralized control and monitoring
station in a reasonable period of time, the system is to activate the engineers’ alarm audible in the engineers’
accommodations. The means for silencing locally at the alarm monitoring stations is not to be provided for
fire alarms.

33 Firefighting Arrangements for Propulsion Machinery Space Fires

33.1 Location
The firefighting arrangements are to be centralized in a location outside of the propulsion-machinery space.

33.3 Fire-fighting Controls

Firefighting arrangements are to be provided with remote manual controls for the operations detailed in the
following list. These controls are to be capable of being tested to the satisfaction of the Surveyor.
33.3.1 (2010)
Stopping of ventilation fans serving the machinery-space. See 4-6-2/19.1.1.
33.3.2 (2010)
Stopping of fuel oil, lubricating oil and thermal oil system pumps. See 4-6-2/19.1.2.
33.3.3 (2010)
Stopping of forced and induced draft fans of boilers, inert gas generators and incinerators, and of
auxiliary blowers of propulsion diesel engines. See 4-6-2/19.1.2.
33.3.4
Closing propulsion-machinery space fuel oil tanks suction valves. (See 4-5-1/5.5).
33.3.5 (2010)
Closing machinery-space skylights, openings in funnels, ventilator dampers and other openings.
33.3.6
Closing machinery-space watertight and fire-resistant doors.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

33.3.7
Starting the emergency generator or connecting a source of emergency power, unless automatic
operation is provided.
33.3.8 (2004)
Operation of a fire pump located outside of the propulsion-machinery space, including associated
valves necessary to deliver the required capacity to the fire main. However, valves located near the
pump need not be provided with remote operation from the fire fighting station if they are kept
locked open (LO) or closed (LC), as appropriate, to provide immediate water supply to the fire
main. The position of the valves (open or closed) is to be clearly marked. Where the sea chest
valve is located in the same compartment as the fire pump and the sea chest valve is kept locked
open, a high-level bilge alarm is to be fitted in the fire pump space. If the sea chest is located in a
different space than the compartment containing the fire pump, then a high-level bilge alarm is to
be fitted in the fire pump space, as well as the compartment containing the sea chest, in order to
detect possible flooding in each of these spaces. The high-level bilge alarm is to sound in the
centralized control station.
33.3.9
Releasing of the fire-fighting media for the propulsion-machinery space. This release is to be
manual and not initiated automatically by signals from the fire-detecting system.

33.5 Fire Detection and Alarm Systems

See 4-7-4/29.5.

33.7 Fire Alarm Call Points

Manually operated fire alarm call points are to be provided in, and in the passageways leading to, the
propulsion-machinery space.

35 Communications
The communication system required by 4-7-2/13 is to include the engineer’s accommodations area, if provided.

37 Sea Trials
In addition to the requirements in 4-7-3/27, effective operation of the following is to be demonstrated to the
satisfaction of the Surveyor. With the exception of 4-7-4/37.9, it is recommended that these demonstrations
or tests be carried out before sea trials and are to include simulated failures so that proper corrective
actions may be carried out and witnessed by the Surveyor.

37.1 Automatic or Remote Control and Monitoring System for Propulsion Machinery and
Electrical Power Generating Machinery
In addition to the verification of required control responses, alarms and displays, this demonstration is to
include the automatic transferring of the required standby vital auxiliary pumps.

37.3 Local Control

Local control of the propulsion machinery is to be demonstrated.

37.5 Fire Control and Alarm System

In addition to the verification of required detectors, displays and call points and where the fire main is not
maintained pressurized, it is to be demonstrated that at least one of the main fire pumps can be started from
the station in the navigation bridge.

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Section 4 Vessels Classed with ACCU Notation 4-7-4

37.7 Bilge Detection System

Where provided, automatic starting of the propulsion-machinery space bilge pumps is to be demonstrated.

37.9 Operational Test of Propulsion Machinery

After the propulsion machinery has been running for at least two hours, the ability to control the machinery
functions correctly for all loads and engine maneuvers without any manual intervention in the propulsion-
machinery space is to be demonstrated for an additional period of four hours. Propulsion machinery or
engine response to throttle control demands is to be tested during the trials and after final adjustments to
demonstrate that no part of the plant or engine is jeopardized by the rate at which the throttle is moved
from one extreme position to the other. The loss of electric power is to be simulated with the main engine
running.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 1
Tests for Unit Certification of Control, Monitoring and Safety Equipment (2008)
PROCEDURE
No TEST ACCORDING. TO: TEST PARAMETERS OTHER INFORMATION
[See Note]
1. Visual --- --- Conformance to drawings, design
inspection data
Quality of workmanship and
construction
2. Performance Manufacturer’s Standard atmosphere conditions Confirmation that operation is in
test performance test Temperature: 25°C (77°F) ± 10°C (18°F) accordance with the requirements
program based upon specified for particular systems or
specification and Relative humidity: 60% ± 30% equipment;
relevant Rule Air pressure: 96 kPa (0.98 kgf/cm2, 13.92 psi) Checking of self-monitoring
requirements ± 10 kPa (0.10 kgf/cm2, 1.45 psi) features;
Checking of specified protection
against an access to the memory;
Checking against effect of
unerroneous use of control
elements in the case of computer
systems.
3. External --- 3 interruptions during 5 minutes; The time of 5 minutes may be
Power supply switching-off time 30 s each case exceeded if the equipment under
failure (2008) test (EUT) needs a longer time for
start up, for example, booting
sequence.
For equipment which requires
booting, one additional power
supply interruption during
booting is to be performed.
Verification of:
the specified action of
equipment upon loss and
restoration of supply;
possible corruption of program
or data held in programmable
electronic systems, where
applicable.

Note: Alternative equivalent testing procedures may be accepted, provided the requirements in the other columns are complied
with.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 2
Control Station in Navigation Bridge
(Applicable to All Classed Vessels) (2011)
Provisions of
Alarm Device on
(), 9)
Item Display (12) Station (1) Remarks
Required for All Vessels 8)
A1 Failure or malfunctioning of x See Notes 2, 10.
system
A2 (2005) Failure, power supply x Main/Standby See Note 2
For non-ACCU vessels, the
failure alarm is applicable to
main power source only.
For ACCU vessels, applicable to
main and emergency power
sources. Automatic transfer for
ACCU vessels only.
(See 4-7-2/11.1.2.)
Control and
Monitoring A3 (2005) Failure, individual x x See Notes 2, 10.
System power supply to control,
monitoring and safety systems
A4 Control station in operation Station
A5 (1998) Control transfer x
acknowledgement switch
A6 Alarm, disabled (override) Disabled See Note 4.
A7 Safety, activation x See Notes 3, 10.
A8 Safety disabled x Disabled See Notes 4, 10.
A9 (1 July 2004) Threshold x For navigation bridge only
warning for safety system (See 4-7-3/23.3)
activations
B1 Remote controls x For each propelling unit and all
units, as applicable
B2 (1998) Propeller shaft, speed Speed See Note 11.
Propulsion, B3 Propeller shaft, direction Direction See Note 11.
General (1998)
B4 (1998) Propeller, pitch Pitch For controllable-pitch propeller
See Note 11.
B5 (1998) Telegraph or similar x See Note 11.
C1 Starting medium, pressure or x Pressure or See Note 5.
Propulsion, level, low level
Starting
C2 Hazardous condition present x See 4-7-3/13.3
Emergency D1 Propulsion x See 4-7-3/19
Shutdown
Required for ACCU or ABCU Classed Vessels
E1 Prime movers, prolonged x Visual display may be
Propulsion operation within critical speed acceptable
range
F1 Start/stop switch x Not required if the fire main is
Fire Pump
maintained pressured
Propulsion, G1 Start/stop switch for starting x Not required for non-reversing
Starting system engines

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 2 (continued)
Control Station in Navigation Bridge
(Applicable to All Classed Vessels) (2011)
Provisions of
Alarm Device on
(1, 9)
Item Display (12) Station (1) Remarks
H1 Start/stop switch for CPP x If provided
Controllable- hydraulic motor
Pitch
H2 CPP hydraulic motor running Running If provided
Propeller
(CPP) H3 Automatic starting of required x If provided
standby pump
Electric I1 Propulsion generator load- x See 4-6-4/3.21.3 & 4-6-4/3.23.3
Propulsion share overload and 4-7-4/19
Summary- J1 Propulsion and associated x See Notes 6, 7.
alarms machinery failure
(7)
Bilges In K1 Level, bilges, high x See 4-7-4/29.1.1
Machine
Space
(7)
Fire in L1 Fire control panel x Fire x See 4-7-4/29.5
Machinery
Space
Vital M1 Start/stop and transfer switches x For ABCU vessels having non-
Auxiliary integrated propulsion machinery
Pumps
Notes:
1 Required actuation device or alarm is denoted by a (x).
2 For each system: control systems, alarm/display systems and safety systems. See 4-7-2/11.1.1 and 4-7-4/11.
3 Actuation of propulsion safeties is to either reduce output or shutdown the propulsion machinery, as required. See
also 4-7-2/7, 4-7-3/15 and 4-7-4/Table 4A through 4-7-4/Table 7.
4 Deactivation means are to be arranged so that such action cannot be done inadvertently. Alternative means to
indicate disabling of safety actions or alarms will be considered.
5 This alarm is also to be provided in the machinery space.
6 This summary-alarm is to be activated by any of the alarm conditions as listed in 4-7-4/Table 4A through
4-7-4/Table 7. See 4-7-4/31.
7 These alarms are also to be alarmed at the engineer’s accommodations, see 4-7-4/31.
8 The listed instrumentation is also applicable to other remote propulsion control stations installed outside of the
navigation bridge. See 4-7-3/25.
9 Provided the audible alarms reactivate automatically after a preset time, audible alarms may be bypassed or deactivated
during machinery start-up.
10 May be arranged as a summary-alarm (common).
11 (1 July 1998) To be provided also at the maneuvering platform.
12 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 3
Centralized Control and Monitoring Station
(Applicable to ACCU or ABCU Vessels) (2011)
Provisions of
Alarm Device on
(1, 6)
Item Display (7) Station (1) Remarks
A1 Failure or malfunctioning of x See Notes 2, 5.
system
A2 Failure, supply x Main/Standby Automatic transfer to standby
supply (2, 5)
A3 Control station in operation Station
A4 (1998) Control transfer x
Control and acknowledgement switch
Monitoring
A5 Control power available, Pressure/Level See Note 5.
System
pressure or level
A6 Alarm, disabled (override) Disabled See Notes 4, 5.
A7 Safety, activation x See Notes 3, 5.
A8 Safety disabled x Disabled See Notes 4, 5.
A9 Safety, disabled (override) x See 4-7-2/7.11 (5)
switch
B1 Remote controls x
B2 Propeller shaft, speed Speed See Note 5.
B3 Propeller shaft, direction Direction See Note 5.
Propulsion, B4 Propeller, pitch Pitch For controllable-pitch
General propeller (6)
B5 Prime movers, critical speed x Visual display may be
acceptable (6)
B6 Engine order telegraph or x Not applicable to certain vessels
similar < 500 GT. See 4-6-2/15.1.2
C1 Starting medium, pressure or x Pressure or See Note 5.
Propulsion, level, low Level
Starting
C2 Hazardous condition present x See 4-7-3/15.5 (5)
Diesel D1 Alarms and displays See 4-7-4/Table 4A & B
Propulsion
Gas Turbine E1 Alarms and displays See 4-7-4/Table 5
Propulsion
F1 Alarms and displays See 4-7-4/Table 6
Electric
Propulsion F2 Propulsion generator load- x See 4-6-4/3.21.3 & 4-6-4/3.23.3
share overload and 4-7-4/19
Elect. Gen. G1 Alarms and displays See 4-7-4/Table 7
Machinery
H1 Level, tank, low x See Note 5.
FO Settling and
H2 Level, tank, high x If automatic filling provided (5)
Daily Service
Tanks H3 Oil temperature, high or oil flow, x Includes L.O. systems (5)
low
FO and LO I1 Level, tank, high x See 4-7-4/29.3.2 (5)
Collect. Tank
High Pres. FO J1 Leakage x See 4-7-4/29.3.1 (5)
System

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 3 (continued)
Centralized Control and Monitoring Station
(Applicable to ACCU or ABCU Vessels) (2011)
Provisions of
Alarm Device on
(1, 6)
Item Display (7) Station (1) Remarks
LO Stern Tube K1 Level, oil, low x See Note 5.
Tank
Bilges in L1 Level, bilges, high x See 4-7-4/29.1.1 (5)
Machinery L2 Excessive running of bilge x If auto, starting provided.
Space pump motor See 4-7-4/29.1.2 (5)
Notes:
1 Required actuation device or alarm is denoted by a (x).
2 For each system: control systems, alarm/display systems and safety systems. See 4-7-2/11.1.1 and 4-7-4/11.
3 Actuation of propulsion safeties is to either reduce output or shutdown the propulsion machinery, as required. See
4-7-3/15 and 4-7-4/Table 4A through 4-7-4/Table 7.
4 Deactivation means are to be arranged so that such action cannot be done inadvertently. Alternative means to
indicate disabling of safety actions or alarms will be considered.
5 For ABCU vessels, only these items and the alarms and displays per 4-7-4/Table 4A through 4-7-4/Table 7, as
applicable, need to be provided on such station.
6 Provided the audible alarms reactivate automatically after a preset time, audible alarms may be bypassed or deactivated
during machinery start-up.
7 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 4A
Monitoring of Propulsion Machinery – Slow Speed (Crosshead) Diesel Engines
(See also 4-7-4/Table 3) (2011)
Automatic Start
of Required
Standby Vital
Alarm Display Auxiliary Pump
Item (11) (1) (16)
with Alarm (1) Remarks (12)
A1 Fuel oil after filter (engine inlet) x Pressure x See Note 3.
pressure – low
A2 Fuel oil before injection pumps, x
temperature – high (or viscosity –
low), and Fuel oil before injection
Fuel Oil pumps, temperature – low (or
System viscosity – high)
A3 Leakage from high pressure pipes x
A4 Fuel oil in daily service tank, low- x See also 4-7-4/25
level
A5 (2010) Common rail fuel oil x
pressure – low
B1 Lube oil to main bearing and thrust x Pressure x See Notes 2, 3, 4.
bearing, pressure-low
B2 Lube oil to crosshead bearing, x Pressure x See Notes 2, 3, 4, 5.
pressure – low
B3 Lube oil to camshaft, pressure – x x Automatic engine
low shutdown (3, 4, 5)
B4 Lube oil to camshaft, temperature – x See Note 5.
high
B5 Lube oil inlet, temperature – high x
B6 Thrust bearing pads or Bearing x Automatic engine
Lube Oil outlet, excessive temperature – shutdown/shutdown (2, 3)
System high
B7 (2009) Oil mist in crankcase, mist x Automatic engine
concentration – high; or shutdown (2, 6)
Bearing temperature - high; or
Alternative arrangements
B8 Flow rate cylinder lubricator, flow x Automatic engine
– low. Each apparatus slowdown (2)
B9 Lubricating tanks, level – low x See Note 7.
B10 (2010) Common rail servo oil x
pressure – low
C1 (2010) Lube oil inlet, pressure – low x See Note 13
Turbocharger C2 (2010) Lube oil outlet (each bearing), x See Note 14
System temperature – high
C3 Turbocharger speed Speed
D1 Coolant inlet, pressure – low x x Automatic engine
slowdown (2, 3, 8)
D2 Coolant outlet (each cylinder), x Automatic engine
Piston Cooling temperature – high slowdown (2)
System D3 (2010) Coolant outlet (each x Automatic engine
cylinder), flow – low slowdown (2, 15)
D4 Coolant in expansion tank, level – x
low
S. W. Cooling E1 Sea water cooling, pressure – low x x See Note 3.

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Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 4A (continued)
Monitoring of Propulsion Machinery –Slow Speed (Crosshead) Diesel Engines
(See also 4-7-4/Table 3) (2011)
Automatic Start
of Required
Standby Vital
Alarm Display Auxiliary Pump
Item (11) (1) (16)
with Alarm (1) Remarks (12)
F1 Water inlet, pressure-low x x Automatic engine
slowdown (2, 3)
F2 Water outlet (for each cylinder), x Automatic engine
Cylinder Fresh temperature-high, or Water outlet slowdown (2, 9)
Cooling Water (general), temperature-high
System F3 Oily contamination of engine x See Note 10.
cooling water system
F4 Cooling water in expansion tank, x
level – low
G1 Starting air before main shut-off See item C1 in 4-7-4/Table
valve, pressure – low 3
Air System
G2 Control air, pressure – low x
G3 Safety air, pressure – low x
H1 Scavenge air receiver Pressure
H2 Scavenge air box, temperature – x Automatic engine
Scavenge Air
high (fire) shutdown (2)
Systems
H3 Scavenge air receiver water, level – x
high
I1 Exhaust gas after each cylinder, x Temp. Automatic engine
temperature – high slowdown (2)
I2 Exhaust gas after each cylinder, x
deviation from average,
Exhaust Gas temperature – high
System
I3 Exhaust gas before each T/C, x Temp.
temperature – high
I4 Exhaust gas after each T/C, x Temp.
temperature – high
J1 Fuel valve coolant, pressure – low x x See Note 3.
J2 Fuel valve coolant, temperature – x
Fuel Valve
high
Coolant
J3 Fuel valve coolant in expansion x
tank, level – low
K1 Engine speed/direction of rotation Speed/
rotation
K2 Engine overspeed x Automatic engine
Engine
shutdown (3)
K3 (1998) Direction of rotation – x
Wrong way
L1 Control, alarm or safety system, x
Power Supply
power supply

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Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 4A (continued)
Monitoring of Propulsion Machinery – Slow Speed (Crosshead) Diesel Engines
(See also 4-7-4/Table 3) (2011)
Notes:
1 Required alarm or starting of standby pump is denoted by a (x).
2 A common sensor for alarm/display and automatic slowdown is acceptable.
3 Separate sensors are required for a) alarm/automatic starting of required standby pump, and b) automatic engine
shutdown.
4 Automatic engine shutdown is to be alarmed and effected upon loss of oil pressure.
5 If separate lube oil systems are installed.
6 (2009) For engines having a power of 2250 kW (3000 hp) and above or having a cylinder bore of more than 300 mm
(11.8 in.). See 4.2.1/7.2 of the Steel Vessel Rules.
7 Where separate lubricating oil systems are installed (e.g., camshaft, rocker arms, etc.), individual level alarms are
required for the tanks.
8 The slowdown is not required if the coolant is oil taken from the main cooling system of the engine.
9 Where one common cooling space without individual stop values is employed for all cylinder jackets.
10 Where main engine cooling water is used in fuel and lubricating oil heat exchangers.
11 For ABCU vessels having integrated propulsion machinery, exemption from the listed instrumentation and safety
provisions will be considered.
12 (1998) Instead of automatic slowdown, manual slowdown will be acceptable, provided visual/audible alarm with
illumination sign “Reduced Power” is located in the navigation bridge.
13 (2010) Unless provided with a self-contained lubricating oil system integrated with the turbocharger.
14 (2010) Where outlet temperature from each bearing cannot be monitored due to the engine/turbocharger design
alternative arrangements may be accepted. Continuous monitoring of inlet pressure and inlet temperature in combination
with specific intervals for bearing inspection in accordance with the turbocharger manufacturer’s instructions may
be accepted as an alternative.
15 (2010) Where outlet flow cannot be monitored due to engine design, alternative arrangements may be accepted.
16 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

338 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 4B
Monitoring of Propulsion Machinery –
Medium/High (Trunk Piston) Speed Diesel Engines
(See also 4-7-4/Table 3) (2011)
Automatic Start
of Required
Standby Vital
Alarm Display Auxiliary Pump
Item (11) (1) (14)
with Alarm (1) Remarks (12)
A1 Fuel oil after filter (engine inlet), x Pressure x See Note 3
pressure – low
A2 Fuel oil before injection pumps, x See Note 5
temperature – high (or viscosity –
low), and Fuel oil before injection
Fuel Oil pumps, temperature – low (or
System viscosity – high)
A3 Leakage from high pressure pipes x
A4 Fuel oil in daily service tank, level x See also 4-7-4/25
– low
A5 (2010) Common rail fuel oil x
pressure – low
B1 Lube oil to main bearing and x Pressure x Automatic engine
thrust bearing, pressure – low shutdown (3, 4)
B2 (1998) Lube oil filter differential, x Pressure x See Note 3
pressure – high
B3 Lube oil inlet, temperature – high x Temp.
B4 (2009) Oil mist in crankcase, mist – x Automatic engine
Lube Oil concentration high; or shutdown (6)
System
Bearing temperature – high; or
Alternative arrangements
B5 Flow rate cylinder lubricator, flow x (1997) Automatic engine
– low. Each apparatus slowdown (2, 10)
B6 (2010) Common rail servo oil x
pressure – low
C1 Turbocharger lube oil inlet, x Pressure See Note 7
pressure – low
Turbocharger
C2 (2010) Turbocharger oil temp., x Temp. See Note 13
each bearing – high
S. W. Cooling D1 Sea water cooling, pressure – low x Pressure x See Note 3
E1 Water inlet, pressure-low or flow – x Press. or x Automatic engine
low flow slowdown (2, 3)
Cylinder
E2 Water outlet (general), x Temp. Automatic engine
Fresh Cooling
temperature – high slowdown (8)
Water System
E3 Cooling water in expansion tank, x
level – low
F1 Starting air before main shut-off See item C1 in 4-7-4/Table 3
Air valve, pressure – low
System
F2 Control air, pressure – low x Pressure
Scavenge Air G1 Scavenge air receiver, temperature x
System – high
H1 Exhaust gas after each cylinder, x Temp. Automatic engine
temperature – high slowdown (2, 9)
Exhaust Gas
System H2 Exhaust gas after each cylinder, x See Note 9
deviation from average,
temperature – high

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 339
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 4B (continued)
Monitoring of Propulsion Machinery –
Medium/High (Trunk Piston) Speed Diesel Engines
(See also 4-7-4/Table 3) (2011)
Automatic Start
of Required
Standby Vital
Alarm Display Auxiliary Pump
Item (11) (1) (14)
with Alarm (1) Remarks (12)
I1 Engine speed Speed
Engine I2 Engine overspeed x Automatic engine
shutdown (3)
J1 Control, alarm or safety system, x
Power Supply
power supply failure
Notes:
1 Required alarm or starting of standby pump is denoted by a (x).
2 A common sensor for alarm/display and automatic slowdown is acceptable.
3 Separate sensors are required for a) alarm/automatic starting of required standby pump, and b) automatic engine
shutdown.
4 Automatic engine shutdown is to be alarmed and effected upon loss of oil pressure.
5 For heavy fuel oil burning engines only.
6 (2009) For engines having a power of 2250 kW (3000 hp) and above or having a cylinder bore of more than 300 mm
(11.8 in.). Single sensor having two independent outputs for initiating alarm and for shutdown will satisfy for
independence of alarm and shutdown. See 4-2-1/7.2 of the Steel Vessel Rules.
7 (2010) Unless provided with a self-contained lubricating oil system integrated with the turbocharger.
8 Two separate sensors are required for alarm and slowdown.
9 For engine power > 500 kW/cyl.
10 If necessary for the safe operation of the engine.
11 For ABCU vessels having integrated propulsion machinery, exemption from the listed instrumentation and safety
provisions will be considered.
12 (1998) Instead of automatic slowdown, manual slowdown will be acceptable, provided visual/audible alarm with
illumination sign “Reduced Power” is located in the navigation bridge.
13 (2010) Where outlet temperature from each bearing cannot be monitored due to the engine/turbocharger design
alternative arrangements may be accepted. Continuous monitoring of inlet pressure and inlet temperature in
combination with specific intervals for bearing inspection in accordance with the turbocharger manufacturer’s
instructions may be accepted as an alternative.
14 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

340 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 5
Monitoring of Propulsion Machinery – Gas Turbine
(See also 4-7-4/Table 3) (2011)
Automatic
Starting of
Alarm Required Standby
(1)
Item Display (6) Pump (1,5), Remarks
A1 Pressure, low x Pressure x (1999)
A2 (1999) Pressure, low-low x Turbine automatic
shutdown (3)
Lube Oil (2) A3 Temperature, inlet – high x Temperature
A4 Differential pressure, filter – x
high
A5 Level, tank – low x In gravity tank and sump
Bearings B1 Temperature – high x Main bearings
Cooling C1 Pressure or flow – low x
Medium C2 Temperature – high x
D1 Pressure or flow – low x Pressure or
flow
D2 (1999) Temperature – low or x Temperature For heavy fuel
Fuel
viscosity – high or Viscosity
D3 (1999) Temperature – high or x For heavy fuel
viscosity – low
E1 Temperature – high x Temperature
(1999)
Exhaust Gas E2 Temperature – high-high x (1999) Turbine automatic
shutdown (3)
E3 Temperature deviation – high x
F1 Vibration level – high x
Turbine F2 Vibration level – high-high x (1999) Turbine automatic
shutdown (3)
G1 Axial displacement – high x
G2 (1999) Axial displacement – x Turbine automatic
Rotor high-high shutdown (3,4)
G3 Overspeed x (1999) Turbine automatic
shutdown
Automatic H1 (1999) Failure x
Starting
Ignition and I1 (1999) Failure x Turbine automatic
Flame shutdown (3)
J1 (1999) Pressure, inlet – low x
Compressor J2 (1999) Pressure, inlet – x Turbine automatic
low-low shutdown (3)
Control K1 (1999) Failure x
System

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 341
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 5 (continued)
Monitoring of Propulsion Machinery – Gas Turbine
(See also 4-7-4/Table 3) (2011)
Notes:
1 Required alarm or starting of standby pump is denoted by a (x).
2 Individual alarms are required where separate systems (e.g., reduction gear, bearing, etc.) are installed.
3 (1999) The automatic shutdown is to be effected upon reaching the preset level (high-high or low-low, where
applicable) or the event.
4 (1999) Automatic shutdown is not required where roller bearings are provided.
5 For ABCU vessels having non-integrated propulsion machinery, starting of required standby pump is to be alarmed.
6 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

342 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 6A
Monitoring of Propulsion Machinery – Electric
(See also 4-7-4/Table 3) (2011)
Item Alarm (1) Display (3) Remarks
A1 Pressure, bearing, lube oil inlet – low x Pressure Prime mover automatic shutdown
A2 Voltage – off-limits x Voltage To read all phases and at least one bus (2)
A3 Frequency – off-limits x Frequency
Propulsion
Generator A4 Current Current To read all phases (2)
A5 Temperature, stationary windings – x Temperature To read all phases; for generators
high > 500 kW
A6 Transfer of standby generator x
B1 Pressure, bearing, lube oil inlet – low x Pressure
B2 Voltage, armature – off-limits x Voltage To read all phases and at least one bus
B3 Voltage, field Voltage
B4 Frequency – off-limits x Frequency
B5 Current, armature Current To read all phases
B6 Current field Current For synchronous motors
Propulsion
A.C. Motor B7 Ground lights or similar Status
B8 Temperature, stationary windings – x Temperature To read all phases; for motors >500 kW
high
B9 Motor running Running
B10 Transfer of standby motor x
B11 Motor cooling medium temperature – x Temperature If required
high
C1 Pressure, bearing, lube oil inlet – low x Pressure Automatic shutdown
C2 Voltage armature x Voltage
C3 Voltage, field Voltage
C4 Current, armature Current
Propulsion C5 Current, field Current
D.C. C6 Ground lights or similar Status
Motor
C7 Motor running Running
C8 Failure of on-line motor x
C9 Transfer of standby motor x
C10 Motor cooling medium temperature – x Temperature If required
high
D1 Voltage, SCR Voltage
D2 Current, SCR Current
D3 Overloading conditions, high current x Alarms before protective device is
Propulsion
activated
Semi-conductor
Rectifier (SCR) D4 Open/close position for assignment Position
switches
D5 SCR cooling medium temperature – x Temperature If required
high
Notes:
1 Required alarm is denoted by a (x).
2 For D.C. generators. Additionally, field voltmeters and ammeters are to be included.
3 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 343
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 6B
Instrumentation and Safety System Functions in Centralized Control Station –
Generator Prime Mover for Electric Propulsion (2011)
Auto Notes
Auto
Systems Monitored parameters A D shut
start [ A = alarm. D = display. x = apply. ]
down
Trunk Piston Type Diesel Engines
Fuel E1 Fuel oil after filter (engine inlet), x x x
Oil Pressure – low
E2 Fuel oil before injection pumps, x For heavy fuel oil burning engines
temp. – high (or viscosity – low) only.
E3 Fuel oil before injection pumps, x For heavy fuel oil burning engines
temp. – low (or viscosity – high) only.
E4 Leakage from high pressure pipes x
E5 Fuel oil service tank, level – low x High level alarm is also required if
without suitable overflow
arrangements.
E6 (2010) Common rail fuel oil x
pressure – low
Lubricating F1 Lub. oil to main bearing, pressure x x x x
Oil – low
F2 Lub. oil filter differential, x x
pressure – high
F3 Lub. oil inlet, temp. – high x x
F4 (2009) Oil mist in crankcase, mist x x (2009) For engines having power of
concentration – high; or 2250 kW (3000 hp) and above or
Bearing temperature – high; or having cylinder bore of more than
Alternative arrangements 300 mm (11.8 in.).
Single sensor having two independent
outputs for initiating alarm and for
shutdown will satisfy independence
of alarm and shutdown.
See 4-2-1/7.2 of the Steel Vessel Rules.
F5 Each cylinder lubricator, flow rate x If necessary for the safe operation of
– low the engine.
F6 (2010) Common rail servo oil x
pressure - low
Sea Cooling G1 Sea water cooling system x x x
Water pressure – low
Cylinder H1 Water inlet, pressure – low or x x x
Fresh Water flow – low
Cooling H2 Water outlet (general), temp. – x x
high
H3 Cooling water expansion tank, x
level – low
Compressed J1 Starting air before shut-off valve, x x
Air pressure – low
J2 Control air pressure – low x x
Exhaust K1 Exhaust gas after each cylinder, x x For engine power > 500 kW/cylinder
Gas temp. – high

344 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 6B (continued)
Instrumentation and Safety System Functions in Centralized Control Station –
Generator Prime Mover for Electric Propulsion (2011)
Auto Notes
Auto
Systems Monitored parameters A D shut
start [ A = alarm. D = display. x = apply. ]
down
Gas Turbines
(2010) L1 Turbocharger oil inlet pressure – x Unless provided with a self-contained
Turbocharger low lubricating oil system integrated with
the turbocharger
L2 Turbocharger oil temp., each x Where outlet temperature from each
bearing – high bearing cannot be monitored due to
the engine/ turbocharger design,
alternative arrangements may be
accepted. Continuous monitoring of
inlet pressure and inlet temperature in
combination with specific intervals
for bearing inspection in accordance
with the turbocharger manufacturer’s
instructions may be accepted as an
alternative.
Engine M1 Over speed x x
Power N1 Main x x
Supply N2 Emergency x
Fuel Oil O1 Pressure or flow – low x x
O2 Temperature – high and low (or x x For heavy fuel oil.
viscosity – low and high)
Lubricating P1 Inlet pressure – low x x x x
Oil P2 Inlet temperature – high x x
P3 Bearing temp. or bearing oil x x
outlet temp. – high
P4 Filter differential pressure – high x
P5 Tank level – low x x
Cooling Q1 Pressure or flow – low x x
Medium Q2 Temperature – high x
Starting R1 Stored starting energy level – low x
R2 Ignition failure x x
Combustion S1 Combustion or flame failure x x
Exhaust Gas T1 Temperature – high x x x
Turbine U1 Vibration level – high x x
U2 Rotor axial displacement – large x x Auto shutdown may be omitted for
rotors fitted with roller bearings
U3 Overspeed x x
U4 Vacuum at compressor inlet – x x
high
Power V1 Main x x
Supply V2 Emergency x

(2011) Display = display of the analog or digital signal for the monitored parameter. The display of the signal is to
provide indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.)
or status indication. The engineering unit is to effectively display the relevant information concerning
the monitored parameter. An alternative engineering unit which provides equivalent effectiveness,
may be considered.
Auto start = automatic starting of a standby pump, along with activation of suitable alarm.
Auto shut down = automatic stopping of the diesel engines and gas turbine, along with activation of suitable alarm.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 345
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 4 Vessels Classed with ACCU Notation 4-7-4

TABLE 7
Monitoring of Auxiliary Prime-movers and Electrical Generators
(See also 4-7-4/Table 3) (2011)
Item Alarm Display Remarks
(1) (4)

A1 Pressure, lube oil inlet – low x Pressure Automatic engine shutdown

A2 Temperature, inlet – high x Temperature
Lube Oil
A3 (2010) Common rail servo oil x
pressure – low
B1 Pressure or flow – low x Pressure, or
Cooling flow
Medium B2 Temperature, outlet – high x
B3 Level, expansion tank – low x If separate from main system
C1 Fuel oil leakage from pressure pipe x
C2 Level, in fuel oil daily service tank – x See also 4-7-4/25
Diesel Fuel
low
Engine Oil
C3 (2010) Common rail fuel oil x
pressure – low
D1 Oil mist in crankcase, mist x Automatic engine shutdown (2)
concentration – high; or
Crankcase
Bearing temperature – high; or
Alternative arrangements
Starting E1 Pressure or level – low x Pressure, or
Medium level
F1 Device activated x Automatic shutdown. See
Overspeed 4-2-1/7.5.3 and 4-2-1/7.3 of the
Steel Vessel Rules
G1 Pressure, bearing, lube oil inlet – x Pressure Prime mover automatic
low shutdown
G2 Voltage – off-limits x Voltage To read all phases and at least
Electrical one bus (3)
Generator
G3 Frequency – off-limits x Frequency
G4 Current – high x Current To read all phases (3)
G5 Transfer of standby generator x
Notes:
1 Required alarm is denoted by a (x).
2 (2009) For engines having a power of 2250 kW (3000 hp) and above or having a cylinder bore of more than 300 mm
(11.8 in.). Single sensor having two independent outputs for initiating alarm and for initiating alarm and for
shutdown will satisfy independence of alarm and shutdown. See 4-2-1/7.2 of the Steel Vessel Rules.
3 For D.C. generation. Additionally, field voltmeters and ammeters are to be included.
4 (2011) Display of the analog or digital signal for the monitored parameter. The display of the signal is to provide
indication of the monitored parameter in engineering units (such as degrees, PSI, RPM, etc.) or status indication.
The engineering unit is to effectively display the relevant information concerning the monitored parameter. An
alternative engineering unit which provides equivalent effectiveness, may be considered.

346 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
PART Section 5: Vessels Classed with ABCU Notation

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 5 Vessels Classed with ABCU Notation

1 General
The requirements in this subsection apply to vessels capable of operating as ACCU classed vessels but
because of their compact propulsion-machinery space design are not fitted with the means to control the
propulsion and its associated machinery from a centralized location within the propulsion-machinery space.
Except as noted herein, the requirements in Sections 4-7-1 through 4-7-4, as applicable, are to be complied
with.

3 Station in Navigation Bridge

Controls, alarms and displays as listed in 4-7-4/7 are to be provided on the station in the navigation bridge.
See 4-7-4/Table 2. For vessels having nonintegrated propulsion machinery, the means for starting, stopping
and transferring vital auxiliary pumps (see 4-7-4/15) are to be fitted at the station in the navigation bridge
and may also be fitted in the centralized station. See 4-7-1/5.41 for definition of integrated propulsion
machinery.

5 Centralized Monitoring Station

The requirements in 4-7-4/9 are applicable, except that the centralized station need not be provided with
propulsion controls, but is to include displays and alarms needed for the monitoring of the propulsion
machinery and associated ship’s service systems, electrical power generating machinery, and monitoring of
propulsion-machinery space. The monitoring system is to provide the same degree of equivalency as if the
propulsion-machinery space was manned. See 4-7-4/Table 3 through 4-7-4/Table 7 for required alarms and
displays to be fitted at this station.

7 Communications
Communications, as required in 4-7-2/13, are also to include the centralized monitoring station in the
propulsion-machinery space.

9 Sea Trials
In addition to the trials per 4-7-4/37, successful operation of the propulsion machinery is to be demonstrated
with the propulsion-machinery space unattended for a period of at least 12 hours.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 347
PART Section 6: Vessels Less Than 500 GT Having a Length Equal or Greater Than 20 m (65 ft)

4
CHAPTER 7 Shipboard Automatic or Remote Control and
Monitoring Systems

SECTION 6 Vessels Less Than 500 GT Having a Length Equal

or Greater Than 20 m (65 ft)

1 General
The requirements contained in this Section are intended for vessels less than 500 GT having a length equal
to or greater than 20 m (65 ft). Vessels having a length less than 20 m (65 ft) will be specially considered.
Note: ACCU or ABCU class notation may be granted to vessels of < 500 GT and a length of 20 m (65 ft) ≤ 1 ≤ 46 m
(150 ft), provided that the applicable requirements in Sections 4-7-1 through 4-7-5 are met.

3 Definitions
See 4-7-1/5.

5 Plans to be Submitted
Plans and specifications are to be submitted in accordance with 4-1-1/7 for approval and are to include the
following information.
i) Machinery arrangement plans showing location of control stations in relation to controlled units;
ii) Arrangements and details of control consoles, including front views, installation arrangements together
with schematic diagrams for all power, control and monitoring systems, including their functions;
and a list of alarms/displays, as required in 4-7-6/15.5.
iii) Type and size of all electrical cables and wiring associated with the control systems, including voltage
rating, service voltage and currents together with overload and short-circuit protection;
iv) Description of all alarm and emergency tripping arrangements; functional sketches or description
of all special valves, actuators, sensors and relays;
v) Schematic plans and supporting data of fire-protection and extinguishing systems, including fire-
detection and alarm systems and bilge high water alarms.
vi) Schematic plans of hydraulic or pneumatic control systems.

7 Electrical Cables and Console Wiring

In general, cables are to be used external to the consoles and they are to be of the marine type in accordance
with the applicable parts of Part 4, Chapter 6. Cables in accordance with other standards which are not less
effective will be considered. Cables and console wiring for control and monitoring are to be of the flame-
retarding type and are to be stranded, except that solid conductors may be used in low-energy circuit where
they are properly supported and not subject to undue vibration or movements.

348 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 6 Vessels Less Than 500 GT Having a Length Equal or Greater Than 20 m (65 ft) 4-7-6

9 Alarms
The alarm system is to be able to indicate more than one fault at the same time and be so arranged that
acceptance of one fault is not to inhibit another alarm. Audible alarms are to be maintained until they are
acknowledged, and visual indication is to remain until the fault is corrected.

11 Safety System
Safety systems are to be of the fail-safe type and are to respond automatically to fault conditions that may
endanger the machinery or safety of the crew. This automatic action is to cause the machinery to take the
least drastic action first, as appropriate, by reducing its normal operating output or switching to a stand-by
machinery and last, by stopping it, i.e., disrupting source of fuel or power supply, etc. However, the propulsion
machinery is to automatically shut down upon a loss of lubricating oil or an overspeed condition, and such
conditions are to be alarmed. Where arrangements for overriding the shutdown of the main propelling
machinery are fitted, these are to be as to preclude inadvertent activation. Visual means shall be provided
to show whether or not it has been activated.

13 Bridge Control of Propulsion Machinery

13.1 General
The requirements in 4-7-3/3 through 4-7-3/7 and 4-7-3/19 are applicable.

13.3 Local Control

It is to be possible to control the propelling machinery locally in the case of failure in any part of the automatic
or remote control systems.

13.5 Bridge Control Indicators

Indicators for the following items are to be fitted on the navigation bridge:
i) Propeller speed and direction where fixed pitch propellers are fitted;
ii) Propeller speed and pitch position where controllable pitch propellers are fitted;
iii) For air-started engines, an alarm is to be provided to indicate low starting air pressure and is to be
set at a level which still permits main engine starting operation;
iv) An alarm is to be provided for low control fluid pressure for controllable pitch propellers.

15 Requirements for Periodically Unattended Propulsion Machinery

Spaces

15.1 Fire Protection

15.1.1 Fire Prevention
15.1.1(a) Piping for high pressure fuel injection and return piping on main and auxiliary engines
is to be effectively shielded and secured to prevent fuel or fuel mist from reaching a source of
ignition on the engine or its surroundings. Leakages from such piping are to be collected in a suitable
drain tank provided with high level alarm audible at the navigation bridge.
15.1.1(b) Drip trays for collecting fuel and lubricating oil are to be fitted below pumps, heaters,
burners, tanks not forming part of the vessel’s structure, etc., with connections to a suitable drain
tank with high level alarm audible at the navigation bridge.
15.1.1(c) Where daily service fuel oil tanks are filled automatically or by remote control, means
are to be provided to prevent overflow spillages. Similar consideration is to be given to other
equipment which treat flammable liquids automatically (e.g., fuel oil purifiers), which whenever
practicable shall be installed in special space reserved for purifiers and their heaters.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011 349
Part 4 Vessel Systems and Machinery
Chapter 7 Shipboard Automatic or Remote Control and Monitoring Systems
Section 6 Vessels Less Than 500 GT Having a Length Equal or Greater Than 20 m (65 ft) 4-7-6

15.1.1(d) Where fuel oil daily service tanks or settling tanks are fitted with heating arrangements,
a high temperature alarm, audible at the navigation bridge, is to be provided if the flashpoint of the
fuel oil can be exceeded.
15.1.2 Fire Detection
A fire detection system is to be provided for the machinery spaces.

15.3 Protection Against Flooding

Bilges in machinery spaces are to be provided with a high level alarm in such a way that the accumulation
of liquids is detected at normal angles of trim and heel. The detection system is to initiate an audible and
visual alarm on the navigation bridge.

15.5 Alarms and Displays

The following alarms and displays are to be provided at the navigation bridge.

Items Display Alarm

1 L.O. Pressure to main engine and reduction gear Pressure Low
2 Engine coolant Temperature High
3 Starting air (if applicable) pressure Low
4 Propeller Speed RPM
5 Propeller Direction Ahead
6 or Astern
7 Pitch Pitch
8 Steering gear motor Stopped
9 Control power Available Failure
(1)
10 Generator voltage Volt
11 Generator current Amps (1)
12 Fuel oil day tanks Level (1) Low
13 Fuel oil tanks heater temperature [see 4-7-6/15.1.1(d)] High
14 Oil collection tank [see 4-7-6/15.1.1(a) & 4-7-6/15.1.1(b)] Level (1) High
15 Bilge level Light (1) High
16 Fire alarm Light (1) Fire
Note:
1 As an alternative, these displays may be provided locally.

350 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS UNDER 90 METERS (295 FEET) IN LENGTH . 2011