Parsons Document Number EGP3-07-SP-040-403-030

CHEVRON NIGERIA LIMITED

ESCRAVOS GAS PROJECT – PHASE 3 DEVELOPMENT - ONSHORE

SPECIFICATION NUMBER EGP3–02.01

CATHODIC PROTECTION

REV DATE REVISION BY CL/APPR

0 Oct. 24,2002 Issued for ITB EJ
1 January 22, 2004 Revised for ITB3 RBM DAP

January, 2004 Specification EGP3-02.01 1 OF 30

 REVISION RECORD SHEET

Notes

i.) Revisions numbers shall be A, B, C, etc. up through the issue for Invitation to Bid.

ii.) The issue for Invitation to Bid shall be Revision 0.

iii.) Revisions after the issue for Invitation to Bid shall be 1, 2, 3, etc. Any revisions made after
Revision 0 shall be denoted by a vertical line in the left hand margin against the revised text.

iv.) A brief description of the key changes made in each revision shall be included on this page.

REVISION DESCRIPTION OF REVISION

A Based on Chevron Specification 02.01

B  Updated for EGP3 standards and definitions.

 Removed cathodic protection for piles thoughout spec

 Changed from zone to division type area classification.

 Changed oil filled transformers to dry type.

 Issued for Parsons Review/CNL Review and Comments

0 Issued for ITB

1 Revised for ITB3 – no changes

January, 2004 Specification EGP3-02.01 2 OF 30

 TABLE OF CONTENTS

PAGE

1.0 SCOPE & DEFINITIONS 6

1.1 Scope 6

1.2 Definitions 6

2.0 REFERENCES 6

2.1 Industry Codes 6

2.2 Project Specifications 7

2.3 Standard Drawings 7

3.0 RESPONSIBILITIES AND PRECEDENCE 8

3.1 Responsibilities 8

3.2 Precedence 8

4.0 GENERAL DESIGN PHILOSOPHY 8

4.1 General 8

4.2 Protection Method 9

4.3 Temporary Protection 10

4.4 Protection Criteria 11

5.0 SURVEYS 12

5.1 General 12

5.2 Soil Surveys 12

5.3 Water Circulation and Storage Systems 13

6.0 DESIGN CONSIDERATIONS 14

6.1 Electrical Isolation 14

6.2 Design of Electrical Isolation for Pipework 14

January, 2004 Specification EGP3-02.01 3 OF 30

 6.3 Continuity 15

6.4 Monitoring Facilities 15

7.0 ELECTRICAL CABLING AND CONNECTIONS 17

7.1 Cable Requirements 17

7.2 Junction Boxes 18

7.3 Cable Connection Requirements 18

8.0 SPECIFIC REQUIREMENTS FOR IMPRESSED CURRENT SYSTEMS 19

8.1 Anodes 19

8.2 Backfill Material 20

8.3 Transformer-Rectifiers 20

8.4 Installation Requirements 21

9.0 SPECIFIC REQUIREMENTS FOR SACRIFICIAL ANODE SYSTEMS 22

9.1 Anodes 22

9.2 Installation 23

10.0 AVOIDANCE OF ELECTRICAL INTERFERENCE AFFECTS 24

11.0 INSPECTION AND TESTING OF EQUIPMENT 24

11.1 General 24

11.2 Impressed Current Anodes 24

11.3 Sacrificial Anodes 25

11.4 Transformer – Rectifiers 25

11.5 Isolation Joints 25

11.6 Cabling 26

11.7 Junction Boxes and Surge Arrestors 26

12.0 SITE ACCEPTANCE TESTING AND COMMISSIONING 26

12.1 General 26

January, 2004 Specification EGP3-02.01 4 OF 30

 12.2 Transformer – Rectifiers 26

12.3 Isolation Joints 26

12.4 Cable Connections 27

12.5 Pipe Sleeves 27

12.6 Buried Structures 27

13.0 DOCUMENTATION 28

13.1 Design Specification 28

13.2 Installation and Commissioning Procedures 30

13.3 Operating and Maintenance Manuals 30

January, 2004 Specification EGP3-02.01 5 OF 30

1.0 SCOPE & DEFINITIONS

1.1 Scope
The purpose of this Engineering standard is to define the minimum requirements
for the design, manufacturing, inspection, testing, installation and commissioning
of the cathodic protection systems for the ESCRAVOS Gas EGP3 Project.

This Engineering Standard covers the following items:

● All direct buried or immersed metallic pipework

● All direct buried metallic vessels and tanks

● All above ground, storage tank base plates in direct contact with backfill materials

● Internal surfaces of water tanks

Exceptions to the scope on the basis of high soil resistivities or other factors that
indicate corrosion rates would be minimal, and/or cathodic protection would not
be economical, and alternative corrosion protection systems would provide
adequate life shall be subject to COMPANY review and approval on a case-by-
case basis.
CONTRACTOR shall notify COMPANY of any conflicts between this specification
and other project documents or referenced industry standards.

1.2 Definitions
Definitions used in this specification are as follows:

"COMPANY" is defined as CNL

"CONTRACTOR" is defined as EPC Contractor

"SUPPLIER or SUB-CONTRACTOR" is defined as companies supplying material,

equipment or services to the CONTRACTOR.

"FEED CONTRACTOR" is defined as Parsons

"PROJECT" is defined as the EGP3 Onshore Project

2.0 REFERENCES

The following documents are hereby referenced and are considered part of this
specification:

2.1 Industry Codes

NACE RP0169 Control of External Corrosion on Underground or
Submerged Metallic Piping Systems

January, 2004 Specification EGP3-02.01 6 OF 30

 NACE RP0177 Mitigation of Alternating Current and Lightning Effects on
Metallic Structures and Corrosion Control Systems

NACE RP0193 External Cathodic Protection of On-Grade Metallic Storage

Tank Bottoms.

NACE RP0196 Galvanic Anode Cathodic Protection of Internal

Submerged Surfaces of Steel Water Storage Tanks

NACE RP0285 Corrosion Control of Underground Storage Tank Systems

by Cathodic Protection

NACE RP0286 The Electrical Isolation of Cathodically Protected Pipelines

NACE RP0388 Impressed Current Cathodic Protection of Internal

Submerged Surfaces of Steel Water Storage Tanks

NACE RP0572 Design, Installation, Operation and Maintenance of

Impressed Current Deep Groundbeds

ASTM B265 Standard Specification for Titanium and Titanium Alloy

Strip, Sheet and Plate.

API RP0651 Cathodic Protection of Aboveground Petroleum Storage

Tanks.

API RP1632 Cathodic Protection of Underground Petroleum Storage

Tanks and Piping Systems.EGP3-12.01 General
Electrical

2.2 Project Specifications

EGP3-12.01 “General Electrical Specification”

EGP3-12.16 “DC Supply”

EGP3-12.13.1 “Wire and Cable”

EGP3-15.00 “Loss Prevention Design Basis”

2.3 Standard Drawings

Not applicable

January, 2004 Specification EGP3-02.01 7 OF 30

3.0 RESPONSIBILITIES AND PRECEDENCE

3.1 Responsibilities
CONTRACTOR shall be responsible for verifying the final scope of cathodic
protection and for the final detailed design in accordance with the requirements
of this Engineering Standard and industry codes and standards. CONTRACTOR
shall identify all metallic, direct buried pipes and pipelines where failure would
result in risk to health, safety or the environment and/or plant operability and
submit a detailed scope for COMPANY review and approval. As a minimum, all
hydrocarbon and closed drains shall be included.

CONTRACTOR shall ensure that the requirements specified herein are

incorporated into any procurement specifications, material or sub-contract
requisitions and/or other purchase documentation produced by, or on behalf of,
CONTRACTOR.

3.2 Precedence
Any conflict between this Engineering Standard, other COMPANY
documentation, industry codes and standards and local regulations shall be
referred to COMPANY for clarification prior to proceeding.

Any deviations to the requirements of this Engineering Standard shall be subject

to COMPANY review and approval before proceeding.

4.0 GENERAL DESIGN PHILOSOPHY

4.1 General
4.1.1 The cathodic protection system shall be designed in accordance with the
requirements of this Engineering Standard and the applicable sections of
the following:

Component Referenced Standards(1)(2)

Onshore buried pipework NACE RP0169, NACE RP0177, BS
7361, Pt.1
Onshore buried vessels and tanks NACE RP0285, API RP1632,
BS7361, Pt.1
Internals of water storage tanks NACE RP0196
Aboveground, storage tank base plates NACE RP0193, API RP651

Notes:

1. Standards and other documents referenced within the text of the above
standards shall also apply to the design of the cathodic protection system
as applicable and shall form part of the CONTRACTOR’s design
submission for COMPANY review and approval.

January, 2004 Specification EGP3-02.01 8 OF 30

 2. Where the text of the above referenced standards uses the word ”should”,
this shall be replaced by “shall” to indicate a mandatory requirement. Any
deviation to this shall be subject to COMPANY review and approval.

4.1.2 The cathodic protection system shall be designed to protect each of the
structures in paragraph 4.1.1 continuously for a minimum period of 30
years.

4.1.3 CONTRACTOR shall ensure that the design of the cathodic protection
system is performed by a competent, experienced person, holding
certification by NACE International as a Cathodic Protection Specialist, or
equivalent national or international certification. CONTRACTOR shall
submit such evidence to COMPANY for review.

4.1.4 Equipment and materials shall be selected, designed and manufactured

for continual operation under the applicable site conditions.
CONTRACTOR shall ensure that due consideration is taken of the
tropical, marine environment with potentially corrosive saline conditions,
in the design and specification of the cathodic protection system.

4.1.5 CONTRACTOR shall ensure that the impact of the electrical grounding
system is included in the design of the cathodic protection system.
Positioning of electrical ground rods in the immediate vicinity of
cathodically protected structures should be minimized as much as
possible. Ground rods that will be electrically continuous with a cathodic
protected structure shall be hot-dipped galvanized steel.

4.1.6 Unless otherwise agreed with COMPANY, the following shall apply:

● For cathodic protection of above ground storage tank base plates,

10% of the base plate area shall be considered to have no external
coating to allow for coating damage during base plate installation and
welding. The operating temperature of the tank shall determine the
appropriate current density to be used.

● For cathodic protection of other buried structures, the calculated

current requirement shall be increased by an additional 25% to allow
for current leakage

● For cathodic protection of the internal surface of water tanks and

vessels, the anode sizing and number shall satisfy both the weight
requirement to achieve the design life and the current requirement
(i.e. the current demand necessary to achieve and maintain
protection).

4.2 Protection Method

4.2.1 An impressed current system shall be designed and installed for the
following:-

● Buried metallic vessels and tanks

January, 2004 Specification EGP3-02.01 9 OF 30

 ● Aboveground storage tank bottom plates; firewater and condensate
storage tanks, as a minimum, shall be included unless the tank is
constructed on a concrete pad. Anodes and header cables shall be
installed during the construction of the foundation. Use the largest
depth of clean “washed” sand fill as practical - allowing anodes to be
placed farther from the tank bottom and requiring fewer anodes. Sand
shall be considered “clean” if testing shows that it has a maximum of
50 ppm of chlorides.

4.2.2 As an exception to the above requirements, sacrificial anodes may be

permitted for the following, subject to COMPANY review and approval:

● Buried metallic vessels and tanks

● Short, buried sections of normally aboveground metallic pipework,

such as at road crossings, piping through bund walls etc.

● To locally supplement impressed current systems in areas of shielding

or current drainage

4.2.3 Sacrificial anodes shall be installed for the following. The use of an
impressed current system in these instances shall be subject to
COMPANY review and approval:-

● The internal surfaces of the firewater tank

● The internal surfaces of sumps and other vessels which will contain
water

● Coated metallic buried or immersed pipework

4.2.4 The number, location, and type of anodes shall be sufficient to ensure the
required current density is applied in a uniform manner throughout the
structure under protection. Details of all positions where anodes are
placed shall be indicated on drawings and submitted for COMPANY
review.

4.2.5 The use of more specialized cathodic protection techniques shall be

subject to COMPANY review and approval.

4.3 Temporary Protection

4.3.1 Temporary cathodic protection is required for impressed current systems
when the period between installation and commissioning of the system
exceeds six months and may be obtained either by installing temporary
power to the transformer-rectifier and gradually energizing the impressed
current system or by installation of temporary sacrificial anodes.

4.3.2 CONTRACTOR shall advise COMPANY of its proposed method of

temporary protection and ensure that suitable provision is made for the
installation, operation, and monitoring of this temporary protection prior to
commissioning of the permanent impressed current system. The facility

January, 2004 Specification EGP3-02.01 10 OF 30

 for final isolation of temporary sacrificial anodes shall be provided.

4.4 Protection Criteria

4.4.1 CONTRACTOR shall advise COMPANY of the protection potentials,
coating breakdown factors, and current densities used for the design of
the cathodic protection systems. The values shall take into account
metallurgy, protective coatings applied, process conditions, and the
surrounding environment.

4.4.2 The cathodic protection systems shall be designed so that the measured
structure-to-electrolyte potentials fall within the following recommended
ranges:-

Application/ Environment Protection Protection Reference

Potential Potential
Less –ve Most –ve Cell
(mV) (mV)
Onshore, aerated Cu/CuSO4
-850 -1200
(instant “off”)
Onshore, anaerobic Cu/CuSO4
-950 -1200
(instant “off”)
Aerated raw water, firewater Cu/CuSO4
-850 -1200
(instant “off”)

Notes:-

1. The above values are based upon protection of iron and steel materials.

2. CONTRACTOR shall check the values against the coating systems chosen and
submit for COMPANY review.

4.4.3 The following current density values are the minimum recommended
values for design of cathodic protection systems for buried or immersed
metallic pipework, vessels, internal surfaces of water tanks, and
aboveground storage tank bottom plates:

Protective Coating Minimum

Current Density
(mA/m2)
Bare Steel 20
3 layer Polyethylene (PE)
0.01
3 layer Polypropylene (PP)
Fusion bonded epoxy (FBE)
Liquid applied epoxy
0.1
Polyurethane
Coal tar enamel
Bitumen 0.3

January, 2004 Specification EGP3-02.01 11 OF 30

 Protective Coating Minimum
Current Density
(mA/m2)
Tape wrap

Notes:-
1. The above values of current density do not account for coating breakdown
during the design life.
2. CONTRACTOR shall check minimum values against the coating systems
chosen and soil resistivity and submit for COMPANY review.

4.4.4 For marine steel structures, coating breakdown factors and current
densities shall be per DNV RP B401. CONTRACTOR shall clearly
specify coating breakdown factors and the initial, mean, and final current
density values and submit for COMPANY review and approval.

4.4.5 CONTRACTOR may recommend lower values of current density where

they are supported by established data from systems of similar design,
coating system, and environment, and offer economic advantage in the
design. Any recommended values shall be submitted to COMPANY for
review and approval.

4.4.6 CONTRACTOR shall handle and install materials in such a manner that
coating damage is minimized. CONTRACTOR shall ensure that any
anticipated coating damage because of handling and installation is
included in the design of the cathodic protection system as bare metal
surface.

5.0 SURVEYS

5.1 General
CONTRACTOR shall perform surveys in those areas where the protected
structures and cathodic protection systems are to be situated.

The surveys shall be performed such that the most severe environmental,
seasonal, and tidal conditions are accounted for.

5.2 Soil Surveys

5.2.1 For buried equipment and aboveground storage tanks, the soil surveys
shall be performed per ASTM G57, and include the following
measurements as a minimum:

● Soil resistivity

● Soil pH

● Soil chloride levels

January, 2004 Specification EGP3-02.01 12 OF 30

 ● Soil sulfate levels

January, 2004 Specification EGP3-02.01 13 OF 30

 5.2.2 CONTRACTOR shall conduct soil surveys over a representative sample
of the anode installation locations. If a remote surface anode bed design
is proposed, soil surveys at 10m intervals over the full length of the
proposed location shall be performed.

5.2.3 For aboveground storage tanks that have a flexible membrane installed
as part of the foundation design, resistivity measurements of the sand
foundation fill shall be performed to support calculations regarding
impressed current systems. CONTRACTOR shall ensure that these
resistivity measurements are performed sufficiently well in advance of the
installation of the foundation fill to permit design of the impressed current
system and shall be re-confirmed once the cathodic protection system is
installed and the foundation backfilled but prior to installation of the tank
base plates.

5.2.4 Resistivity measurements shall be made using a non-contact

electromagnetic instrument (e.g. Geonics), to a depth commensurate with
the burial depth, for soil resistivities in excess of 1000 ohm-cm and the
Wenner 4-pin method for soil resistivities of 1000 ohm-cm or less.

5.2.5 Where it is suspected that conditions may support microbial activity, then
the design should be based upon anaerobic conditions. In this case,
further detailed investigation is not required. Any further soil investigations
to justify a design based upon aerobic conditions (no microbial activity)
shall be subject to COMPANY review and approval.

5.2.6 Any specialized soil surveys that may be required shall be performed by a
specialist SUB-CONTRACTOR, appointed by CONTRACTOR and
subject to COMPANY review and approval. The appointed specialist
shall define and supervise any necessary measurements to assess the
nature and likelihood of the particular concern. Specialized surveys
include investigation of the likelihood and effect of microbial activity and
soil conditions that may contribute to the deterioration of concrete. These
surveys may include measurement of in-situ soil redox potentials,
sulphates, sulphides, carbonate, total dissolved solids, and dissolved
oxygen content.

5.2.7 CONTRACTOR shall ensure that any changes to the soil conditions in the
areas subject to survey are accounted for in determining the
measurements.

5.3 Water Circulation and Storage Systems

For onshore water based systems, water samples shall be taken to measure the
following as a minimum:

● Conductivity

● Dissolved oxygen content

● pH

January, 2004 Specification EGP3-02.01 14 OF 30

6.0 DESIGN CONSIDERATIONS

6.1 Electrical Isolation

6.1.1 Installation of isolating devices shall be minimized within the plant
facilities due to the risk of arcing and interference problems and shall only
be installed where necessary to limit flow of current from cathodically
protected structures. Isolating devices shall not be installed in Class 1,
Division 1 hazardous areas.

6.1.2 Electrical isolation shall be achieved by use of either monobloc isolating

joints, isolating spools, or isolating flanges in accordance with NACE
RP0286, and the rules described here within. Pre-assembled and pre-
tested joints should be provided where possible. Any work involving
electrical connections should be performed with the cathodic protection
power source turned off.

6.1.3 CONTRACTOR shall review the need for electrical isolation at the
following locations in its design submission:

● Between buried pipework or equipment and aboveground pipework or

equipment

● Between buried pipework and equipment with different external

protective coatings

● Between aboveground storage tank nozzles and aboveground

pipework

● At the connection to structures protected by a separate cathodic

protection system

● Electrical and instrument cable conduit and/or cable armour or lead

sheathing

● Reinforcing steel in concrete

● Steel casings at road crossings

● Steel supports

● Electrical earthing systems

6.1.4 There may be circumstances where the isolation requirements above

may not apply. CONTRACTOR shall clearly define where electrical
isolation is to be applied.

6.2 Design of Electrical Isolation for Pipework

6.2.1 Isolating joints/flanges shall not be direct buried, but shall be installed
either aboveground or in a dry inspection pit, for ease of inspection and
maintenance.

January, 2004 Specification EGP3-02.01 15 OF 30

 6.2.2 High voltage protection shall be provided by installing zinc earthing cells
across isolating joints. These shall be included where there is a risk that
the protected structures offer a path for high voltages, sources of which
include; local power systems, risk of lightening strikes, and process fluid
static build up.

6.2.3 All isolation flanges shall have non-metallic flange covers to protect
against ingress of dirt and moisture. The covers shall be of a contrasting
color and include a suitable warning sign to identify it as a cathodic
protection isolation joint.

6.2.4 All isolation joints shall be provided with test stations. These may include
bond boxes and/or resistive bonds depending on the purpose of the joint.

6.3 Continuity
6.3.1 Bonding connections shall be used as far as practicable to interconnect
isolated metallic structures within the scope of a given cathodic protection
system.

6.3.2 Bonds shall be applied across all non-welded joints to ensure electrical
continuity of pipes and pipelines.

6.3.3 Bond boxes shall be provided between parallel underground pipelines.

6.3.4 Bond boxes shall be provided between adjacent structures with separate
cathodically protected systems.

6.3.5 Bond boxes shall also be provided at isolation joints that are used for
separation of adjacent cathodic protection systems or in the management
of interference effects.

6.4 Monitoring Facilities

6.4.1 Permanent potential test boxes shall be installed at the following
locations, as a minimum, to verify the effectiveness of the cathodic
protection system:

● Locations as defined in paragraph 4.5 of NACE RP0169

● Every 500m (or less) for on-plot buried pipework

● At each buried vessel or tank

● At each aboveground storage tank

● At each water tank, if internally cathodically protected

6.4.2 Permanent test points shall be installed at each isolating joint in

accordance with the requirements of Section 7.4 of NACE Standard
RP0286.

January, 2004 Specification EGP3-02.01 16 OF 30

 6.4.3 At least one permanent reference electrode shall be installed for each
protected structure. This is in order to provide an easily accessible
potential measurement reading. For aboveground storage tanks, the
number of permanent reference electrodes shall be in accordance with
paragraph 11.2.4 of NACE RP0193.

6.4.4 Additional permanent reference electrodes shall be provided with the

potential monitoring stations, where high soil IR drops are encountered,
and/or representative protection measurements by portable reference
electrode cannot be easily made.

6.4.5 Buried reference electrodes shall be installed in a backfill material, such

as gypsum, that provides a stable, uniform environment, capable of
retaining moisture.

6.4.6 Separate test polarization coupons should be combined with buried

permanent reference electrodes in the following circumstances:-

● High soil IR drop

● Possibility of stray currents

● Monitoring of buried sacrificial anodes

6.4.7 Copper/copper sulphate reference electrode combinations shall be used

in combination with soil and fresh water unless otherwise agreed with
COMPANY.

6.4.8 The use of alternative reference electrodes shall be subject to COMPANY

review and approval.

6.4.9 Each monitoring station shall be given a unique tag number for future
identification and reference against monitoring records.

6.4.10 In addition to the permanent reference electrodes for aboveground

storage tanks, slotted pipes (50mm diameter) shall be installed across the
diameter of the tank foundation. The slotted pipe material shall be
suitable for the normal operational temperature of the tank and shall be
wrapped with a low weight, water permeable textile to prevent sand
entering the pipe during compaction. Permanent access points for the
temporary installation of portable reference electrodes beneath the tank
periphery shall be installed through the ring wall. CONTRACTOR shall
ensure that the slotted pipes and access tubes are installed during the
ring wall construction and do not clash or interfere with other structures,
pipes etc. and that adequate access is provided for insertion/pulling of the
reference electrodes during monitoring activities.

January, 2004 Specification EGP3-02.01 17 OF 30

7.0 ELECTRICAL CABLING AND CONNECTIONS

7.1 Cable Requirements

7.1.1 Cables shall be copper, sized to minimize the voltage drop throughout the
system to less than 2V. The minimum cable sizes shall be as follows:

● AWG #4 or 25mm² for DC power and bonding cables

● AWG #6 or 16mm2 for anode cables

● AWG #10 or 6mm2 for test cables

7.1.2 Cable insulation shall be suitable for the environment in which it is

installed. All cable insulation shall have a 100V rating, as a minimum. DC
power cable insulation shall be rated for 600V minimum. The following
requirements shall also be met:

● For onshore buried cables, insulation shall be either double layer

polyvinylchloride (PVC/PVC), polyethylene (PE/PE), or cross-linked
polyethylene-polyvinylchloride (XLPE/PVC) as a minimum.
CONTRACTOR shall provide additional protective sheathing for rocky
or aggressive soil conditions

● For cables installed in a marine environment, insulating materials shall

be resistant to both water and chlorides. Cables shall be either double
layer polypropylene (PP/PP), ethylene propylene rubber/chloro-
sulphonated polyethylene (EPR/CSP), neoprene or chloroprene, and
shall be completely waterproofed. Protection shall be provided

● Where cable is buried in congested areas or areas potentially subject to

frequent excavation or damage, the cables shall be either run in a
conduit, be armored, or be protected by other suitable method

7.1.3 All buried cables shall be installed at least 600mm below grade and
without splices. Cable connections shall only be made aboveground and
be tagged with identification labels. CONTRACTOR shall install route
markers to identify the presence of buried cables at intervals of not more
than 100m. Buried cables shall be installed with at least one relief loop
underground.

7.1.4 Where underground cable splice joints are unavoidable, then a

“Scotchcast” epoxy resin kit, or similar, shall be used for sealing the joint.

7.1.5 All above ground cables shall be encased in armored cable and/or cable
trays. If armored cable is used, this shall be isolated from any earthing
system.

January, 2004 Specification EGP3-02.01 18 OF 30

 7.2 Junction Boxes
7.2.1 All connections, including anode cables, above ground splices, test leads,
surge arrestors, bonding, reference electrodes, and negative connections,
shall be made in junction/test/bond boxes, certified for the hazardous
area classification in which they are installed.

7.2.2 Weatherproofing of junction boxes shall meet the minimum degree of

protection NEMA 4X/IP56 in accordance with EGP3-12.01.

7.2.3 Junction boxes for plants containing hazardous areas, shall meet the
requirements of EGP3-12.01. Junction boxes shall not be installed in
Class 1, Division 1 areas.

7.2.4 All junction/test/bond boxes shall be identified by a unique number, shall

be accessible at all times, and shall be constructed to prevent
unauthorized entry, vandalism or damage.

7.2.5 All cables being brought above ground shall enter a junction box via a
buried conduit or other suitable protective shroud, and entrance shall be
by a COMPANY approved fitting/gland.

7.2.6 All cables inside junction/test/bond boxes shall be identified with suitable
tags or labels to indicate the structures to which they are connected.

7.3 Cable Connection Requirements

7.3.1 Connection of cables to structures shall ensure that an electrically
conductive and mechanically secure bond is made. The following are
acceptable methods of connection:-

● Fusion welded metal plate with welded stud bolt connection

● Stud welded bolt

● Thermite brazed copper connection

● Pin brazed connection

7.3.2 The minimum welded plate size shall be 50mm x 50mm x 6mm.

7.3.3 All connections shall be made a minimum of 50mm from other welded
joints.

7.3.4 Thermite brazed connections shall be limited to 15gramme cartridge size

with a maximum cable size of AWG #6 or 16mm². Multiple cable
connections will be necessary for negative connections. Thermite brazing
shall not be used with austenitic stainless of duplex steels.

7.3.5 The connection method shall take into account metallurgical, welding, and
inspection requirements for the base material. Specific attention shall be
paid to satisfying the base metal hardness limits.

January, 2004 Specification EGP3-02.01 19 OF 30

 7.3.6 Connections shall be made prior to testing of pipe, as far as practically
allowed by the pipe spool fabrication method and testing sequence.

7.3.7 Where connections are to be made to internally lined piping, they shall be
made prior to the installation of the internal protective coating/lining, or by
low heat input methods that ensure no damage occurs to the internal
lining. Alternative methods shall be submitted to COMPANY for review
and approval.

7.3.8 Coating repairs to structures after installation of cable connections shall

be performed in accordance with the original protective coating
specification. Epoxy resin cast seals may be an acceptable alternative
method to repair coating damage. All alternative methods shall be subject
to COMPANY review and approval.

8.0 SPECIFIC REQUIREMENTS FOR IMPRESSED CURRENT SYSTEMS

8.1 Anodes
8.1.1 Anodes shall be selected from the following types:-

● High silicon cast iron, with chromium

● Mixed metal oxide (MMO)on a noble metal (such as titanium or

platinum),

● Platinized titanium or niobium

8.1.2 For aboveground storage tanks that have a flexible membrane installed
as part of the foundation design, MMO/Ti anode systems shall be
installed with the following requirements:

● For MMO/Ti systems, all titanium ribbon, conductor bars and connector
assemblies shall be manufactured from ASTM B265, Ti, Gr.1 or
COMPANY approved equivalent. The titanium ribbon anode, with the
exception of the titanium conductor bar, shall be coated with a mixed
metal oxide layer. CONTRACTOR shall confirm the minimum
dimensions of the ribbon and conductor bar during detailed design.

● Multiple power feed cables from the anode junction box to the central
conductor bar shall be provided and the central conductor bar shall be
interconnected to the other conductor bars. The connections between
the cables and the central conductor bar shall be factory made, tested
and epoxy encapsulated for water tightness. No field joints/splices
shall be permitted below the tank base plates.

● A secondary, complete, redundant MMO/Ti anode grid with power feed

cables shall be installed during foundation construction.

January, 2004 Specification EGP3-02.01 20 OF 30

 8.1.3 The number, size and spacing of MMO/Ti grid anodes shall ensure a
sufficient structure-to-soil potential is met over the entire surface area of
the base plates. Maximum spacing between the ribbon anodes shall not
exceed three times the actual distance between the anode grid and the
tank base plates or 1.75m, whichever is less, unless otherwise
recommended by the anode manufacturer and agreed with COMPANY.

8.1.4 Alternative anode selections shall be subject to COMPANY review and

approval.

8.1.5 Anode lead wires shall be one continuous length with no breaks. Splicing
shall be avoided.

8.2 Backfill Material

8.2.1 Backfill for anode beds shall be calcined petroleum coke breeze, with a
low sulphur content (4% or less).

8.2.2 For deep groundbeds, calcined fluid petroleum coke breeze in

accordance with the minimum requirements of NACE RP0572 shall be
used.

8.2.3 Other low resistivity back fill materials may be proposed for COMPANY
review and approval, where the ground conditions dictate.

8.2.4 Pre-packaged anodes, where used, shall be supplied with pre-compacted

calcined fluid petroleum type coke breeze.

8.2.5 Backfill under aboveground storage tanks shall be clean, “washed” sand
with a maximum of 50 ppm of chlorides.

8.3 Transformer-Rectifiers
8.3.1 Transformer-rectifiers (T/R’s) shall be specifically designed for cathodic
protection duties, and shall meet the minimum requirements of this
Engineering Standard.

8.3.2 The T/R shall be dry type for outdoor applications, with double wound
transformer and silicon diode rectifier, and supplied with sunshade for
outdoor installations. Dry type T/R’s may be used for indoor installations.
Electronic switched mode T/R’s shall be subject to COMPANY review and
approval.

8.3.3 T/R’s shall be installed in non-hazardous areas wherever possible. If this

is not practicable, the T/R shall be an oil immersed type and shall meet all
hazardous area classification requirements for the area into which it is
installed. T/R’s shall not be installed into Class 1, Division 1 areas. The
T/R shall have a minimum degree of protection of NEMA 4X/IP56 in
accordance with EGP3-12.01. In all cases, T/R’s shall be protected from
damage by vehicular traffic by four concrete-filled steel posts or
COMPANY approved alternative.

8.3.4 The rectifier shall comply with the requirements of EGP3-12.16.

January, 2004 Specification EGP3-02.01 21 OF 30

 8.3.5 The T/R shall be sized to provide a minimum 25% spare capacity of both
voltage and current requirement determined during detailed design of the
cathodic protection system.

8.3.6 The T/R unit shall be designed to withstand power surges, lightning
strikes, and short circuits of up to 15 seconds duration.

8.3.7 The rectifier output current RMS ripple shall be limited to less than 5% of
the DC output current, through the range 5% to 100% of the full rated
current output.

8.3.8 The current rating of silicon diodes shall be at least 1.25 times the full
current rating of the rectifier.

8.3.9 The T/R shall be provided with continuous reading, flush-mounted DC

voltmeter and ammeter for displaying the measured output voltage and
current. Meters shall be accurate to within 2% of full scale value and
shall be linear from zero to full scale value. Digital meters are also
acceptable.

8.3.10 Control switches and meters shall be accessible and mounted as close as
possible to eye level.

8.3.11 Stepless adjustment should be used where practical. Stepped manual

control may be used for onshore buried structures where a low variation
in output current is expected. Where stepped control is used, then this
shall be by front mounted switches with a maximum step size of 5% of the
full rated voltage. Detachable links or jumps shall not be used. For the
T/R of the system for the internal surfaces of the firewater storage tank ,
the output voltage shall be controlled to provide a constant structure-to-
electrolyte potential using an electrical or electronic automatic control
circuit.

8.3.12 The T/R shall be provided with an “ON/OFF” timer unit and circuit
interrupter on the DC output capable of switching the full output current
for 2 minutes ON and 3 minutes OFF. If the system is protected by more
than one T/R, then the timer units shall be provided with synchronous
switching. The timer unit shall be provided with a bypass for normal
operation.

8.3.13 A power failure signal shall be provided from the T/R for feed back to a
centralized control room.

8.4 Installation Requirements

8.4.1 Impressed current systems shall be installed in accordance with the
requirements of the standards referenced in this specification.

8.4.2 Groundbeds may be either shallow or deep. Deep groundbeds shall be

installed in accordance with the requirements of NACE RP0572.

8.4.3 For deep groundbeds, the fluidized calcined petroleum coke breeze shall
be pumped from the bottom of the hole, and not gravity fed from the top.

January, 2004 Specification EGP3-02.01 22 OF 30

 8.4.4 Groundbed anodes shall be centered within the coke breeze envelope.

8.4.5 For deep groundbeds, the following additional requirements shall be met:

● Subsurface strata shall be logged at 1500mm intervals and at all

formation changes. CONTRACTOR shall note the type of rock or
sediment.

● Before installing anodes, each hole shall be electrically logged at

1500mm intervals, and anodes placed to minimize ground resistance
whilst maintaining a balance with the other anodes.

● Surface casings shall be installed and sealed with a bentonite or

cement seal plug after loading and testing is completed.

● Each hole shall have a vent tube installed concurrently with the first
anode in order to vent dangerous gases that may form due to anode
reactions. The vent tube shall be resistant to chlorides and shall be
perforated from the top of the bottom anode to 5m above the top
anode. It shall extend a sufficient height aboveground to prevent
ingress of water and dirt and have a filter and breather cap installed.

9.0 SPECIFIC REQUIREMENTS FOR SACRIFICIAL ANODE SYSTEMS

9.1 Anodes
9.1.1 Sacrificial anodes shall be selected from the following types. Untried or
special alloy compositions and/or applications shall require COMPANY
review and approval:-

● High purity zinc (99.9% Zn or greater),

● Zinc to US Military Specification MIL-A-18001.

● Magnesium-Aluminum-Zinc alloy

● Magnesium-Manganese alloy

9.1.2 Additions of elements that have a detrimental affect on the anode output,
(e.g. iron, copper, nickel) or that are potential carcinogens (e.g. mercury,
cadmium, tin) shall not be permitted.

9.1.3 The application of Zinc anodes shall be limited to resistivities less than
2000ohm-cm.

9.1.4 The anode selection shall take into account cost, number of anodes
required, ease of installation, lifespan, service temperature, and the risk
of any other detrimental effects due to environmental conditions.

9.1.5 CONTRACTOR shall submit full details of anode compositions and

proposed inspection and test procedures, for COMPANY review and
approval prior to installation.

January, 2004 Specification EGP3-02.01 23 OF 30

 9.1.6 Cast anodes shall be free from through body and surface inclusions,
pores, and longitudinal cracks. Transverse cooling cracks may be
permitted. Casting acceptance criteria shall be submitted to COMPANY
for review and approval.

9.1.7 Anode steel cores shall be blast cleaned to a near-white metal finish and
shall have this finish at the time of casting. Zinc anode inserts may be
galvanized. The core shall be centered in the anode and shall extend a
minimum of 75% of the length of the anode.

9.1.8 The net mass of each anode shall not be less than 95% of the specified
nominal mass.

9.1.9 The anode material shall be bonded to the steel core over a minimum of
90% of the total surface. No individual discontinuity shall exceed 35mm
in length.

9.1.10 Dimensions and positions of inserts shall be within +/-2% tolerance of the
defined dimensions.

9.1.11 Fabricated inserts shall be subject to 20% MPI inspection of completed

welds.

9.1.12 For direct buried anodes, lead wires shall be attached to the core by
brazing or silver soldered and sealed with a water repellent, electrically
insulating material such as epoxy resin with a heat shrinkable sleeve. The
lead wire connection shall have a breaking strength equal to or greater
than the anode cable and shall be capable of supporting the full weight of
the anode. The lead wire shall be a minimum of 10m in length.

9.1.13 Direct buried anodes shall be pre-packaged with a chemical back-fill of

gypsum, bentonite and sodium sulphate, the composition of which shall
be suitable for the specific soil resistivities and ground water encountered.

9.1.14 For anodes with a net weight in excess of 100kg, a destructive test shall
be performed on one anode to check the strength of the bond between
the steel insert and the anode, and the result recorded.

9.2 Installation
9.2.1 Anodes shall be installed in accordance with the standards referenced in
this specification.

9.2.2 Pre-packaged sacrificial anodes for onshore buried structures shall be

installed no closer than 1m from the structure to be protected, and for
buried pipes and pipelines, the top of the anode shall be below the pipe
centerline.

January, 2004 Specification EGP3-02.01 24 OF 30

10.0 AVOIDANCE OF ELECTRICAL INTERFERENCE AFFECTS

The following general requirements shall be noted

1. CONTRACTOR shall ensure that the design of the cathodic protection system
avoids stray currents and other electrical interference effects, such as from direct
current, AC power cables, train traction power supplies, foreign pipelines, other
secondary metallic structures, and neighboring cathodic protection systems.

2. Where CONTRACTOR can show that avoidance is not practicable, it shall

propose mitigating measures to be adopted to minimize the effects on the
cathodic protection system for COMPANY review.

3. The measures adopted by CONTRACTOR shall consider in the first place,

maintaining independence of the cathodic protection systems and structures.
This should include the selection of high standard/high integrity coating systems.
Where this is considered inadequate or impracticable, then consideration may
also be given to the following:-

 Resistive bonding

 Localized sacrificial anodes or impressed current cathodic protection system

 Zinc grounding cells

 Decoupling devices (specific to AC or DC power sources)

11.0 INSPECTION AND TESTING OF EQUIPMENT

11.1 General
11.1.1 CONTRACTOR shall propose the minimum inspection and testing
requirements for all cathodic protection equipment and materials for
COMPANY review and approval. Inspection and testing shall ensure that
the material requirements of this specification and referenced
specifications are satisfied prior to dispatch from manufacturers’ works.
The following requirements are in addition to any site inspection activities.

11.1.2 All electrical equipment shall be inspected against the relevant

requirements of EGP3-12.01.

11.1.3 Final inspection of all equipment described within this section shall
include visual checks to confirm compliance with the specified design
drawings and details.

11.2 Impressed Current Anodes

Inspection and testing of impressed current anodes shall include the following
activities:

January, 2004 Specification EGP3-02.01 25 OF 30

 ● Agreed manufacturer standard tests

● Chemical analysis per heat for cast anodes (at least two samples)

● Review of all material certificates for plating materials, substrates, inserts,

cables, and any other sub-supplied materials integral to the anode construction

● Visual inspection and measurement of cracking and shrinkage of cast anodes

● Measurement of overall dimensions, thicknesses, weights, and positions on at

least a 5% sample basis

11.3 Sacrificial Anodes

Inspection and testing of sacrificial anodes shall include the following activities:-

● Agreed manufacturer standard tests

● Chemical analysis per heat (at least two samples)

● Review of all material certificates for inserts and cables, and any other sub-
supplied materials integral to the anode construction

● Visual inspection of steel inserts’ surface preparation and dimensions, on at

least a 5% sample basis

● Visual inspection and measurement of cracking and shrinkage

● Measurement of overall dimensions, thicknesses, weights, and positions on at

least a 5% sample basis

11.4 Transformer – Rectifiers

11.4.1 A manufacturer’s standard Factory Acceptance Test shall be performed
to demonstrate the capacity and functionality of the transformer –
rectifiers. This procedure shall be submitted by CONTRACTOR for
COMPANY review and approval.

11.4.2 Enclosure certification shall be reviewed to confirm compliance with the

specified enclosure protection and hazardous classification ratings.

11.5 Isolation Joints

11.5.1 Monobloc type isolation joints and isolation spool pieces shall be
hydrostatically tested at the manufacturer’s works in accordance with the
applicable piping code.

11.5.2 The electrical resistance and resistance to sparking of pre-assembled

isolation joints shall be checked using the following tests:-

● Apply 1500V 50Hz AC across the joint for at least 5 minutes without
sparking or insulation breakdown.

January, 2004 Specification EGP3-02.01 26 OF 30

 ● Apply 1000V DC across the joint and measure the resistance. The
resistance shall be greater than 1mega-ohm.

11.6 Cabling
Jun Cabling certificates shall be reviewed prior to shipping to confirm compliance
with the specified size, type, rating, and quantity.

11.7 Junction Boxes and Surge Arrestors

Certification for junction boxes / monitoring stations / bond boxes and surge
arrestors shall be reviewed prior to shipping to confirm compliance with the
specified enclosure protection and hazardous classification ratings.

12.0 SITE ACCEPTANCE TESTING AND COMMISSIONING

12.1 General
12.1.1 Site acceptance testing and commissioning of the cathodic protection
systems shall be undertaken in accordance with the standards referenced
in this specification and this section, as a minimum.

12.1.2 CONTRACTOR shall ensure that commissioning of the cathodic

protection system is integrated into the overall construction and
commissioning activities and schedules.

12.1.3 Stable, effective operation of onshore cathodic protection systems shall

be achieved within 2-4 weeks of the start of commissioning. Ineffective
operation beyond this time shall be investigated and resolved by
CONTRACTOR to COMPANY satisfaction. Any necessary remedial
measures shall be proposed by CONTRACTOR for COMPANY review
and approval.

12.1.4 All measurements, readings, and pertinent data shall be recorded within
the final operating and maintenance documentation described in Section
15.

12.2 Transformer – Rectifiers

Each transformer-rectifier shall undergo a load test prior to initial system
energizing. The T/R shall be run continuously for a minimum of 24 hours at the
maximum current and DC voltage rating. During this test, calibration checks of
the ammeters, voltmeters, and any other instrumentation shall be performed.

12.3 Isolation Joints

12.3.1 All monobloc type isolation joints shall be retested immediately prior to
welding into the pipeline.

January, 2004 Specification EGP3-02.01 27 OF 30

 12.3.2 Insulating flanges and spools should be pre-assembled and tested
immediately prior to welding into the pipeline. Where this is not possible,
the following checks shall be made to ensure adequate performance of
the joint:-

● The individual bolt to flange resistance’s shall be measured prior to

energizing the system for the first time,

● After energizing, the current through the joint shall be measured using
an ammeter, and recorded.

12.4 Cable Connections

12.4.1 Thermite and pin brazing cable connection procedures shall be pre-
qualified by CONTRACTOR by a minimum of three representative
connections on a sample plate of the same type and class of material as
the actual pipe. Fusion and stud welded connections shall be performed
to prequalified welding procedures. The test procedures shall be
submitted by CONTRACTOR for COMPANY review and approval.
Brazing test welds shall be witnessed by COMPANY.

12.4.2 The following test requirements apply specifically to thermite brazing:-

● A single hammer blow using a 1kg hammer shall be applied without

visible cracking or breakage.

● The penetration of the copper joints into the base metal shall be
inspected metallographically. Copper penetration into the base metal
shall not exceed 0.5mm.

● Transverse Vickers hardness checks shall be made to confirm the

relevant base material requirements are satisfied.

12.5 Pipe Sleeves

The electrically isolation of pipe sleeves from the protected pipe is critical. Visual
checks shall be made during installation to ensure satisfactory separation and
prevention of accidental in-fills into the sleeve. Measurements shall be made
before backfill and after completion and recorded, to ensure satisfactory isolation.

12.6 Buried Structures

12.6.1 Prior to energizing the cathodic protection system, the “native” structure
to soil potentials shall be measured at the following locations, as a
minimum:-

● All test stations

● Locations where buried structures protrude above ground

January, 2004 Specification EGP3-02.01 28 OF 30

 12.6.2 The cathodic protection system shall be energized and preliminary
adjustments made to balance the distribution of current and satisfy the
structure to soil protection potential criteria. “On” and “Instant Off”
potential measurements shall be made at the same locations as the
“native” potentials, when the system is first energized and then switched
off.

12.6.3 The current output and potential of the transformer – rectifier shall be
measured and recorded.

12.6.4 The current output from individual impressed current and sacrificial
anodes shall be measured and recorded.

12.6.5 Any effects due to stray current and interference between the cathodically
protected structures, secondary structures, and neighboring cathodic
protection systems shall be determined and corrected as necessary.

12.6.6 Where permanent reference electrodes are installed, the readings shall
be compared with measurements obtained using the portable reference
electrode, in order to validate the permanent reference electrodes.

12.6.7 After a minimum period of two weeks, but no more than four weeks, the
initial polarization testing shall be repeated and system adjustments made
as necessary. Both “On” and “Instant Off” potential measurements shall
be recorded before and after any adjustments.

12.6.8 For aboveground storage tanks, “native”, “On” and “Instant Off” potential
measurements shall be taken utilizing the permanent reference
electrodes.

12.6.9 For water tanks, “native” and “On” potential measurements shall be taken
using a portable copper/copper sulphate reference electrode.
Measurements shall be taken at minimum of three depths, as follows:

● At the tank floor,

● 500mm below the water surface, and

● At a point midway between the two.

13.0 DOCUMENTATION

13.1 Design Specification

13.1.1 CONTRACTOR shall submit a basic design specification for each
cathodic protection system. This shall propose the design philosophies
and outline the selected cathodic protection systems for COMPANY
review and approval before detailed design proceeds. The specifications
shall include the following, as a minimum:

● Design philosophy, including protection criteria, design life, and

referenced codes and standards

January, 2004 Specification EGP3-02.01 29 OF 30

 ● Results and assessment of site surveys

● Outline description of the chosen cathodic protection systems, including

the size, number, and location of anodes / groundbeds, transformer –
rectifiers, as well as control and measurement features, with basic
calculations and economic justifications

● Evaluation of any potential stray current and interference effects, and

also impact from and to any neighboring secondary structures and
other cathodic protection systems

● Definition of the type of isolating joints to be used

● Definition of the type and number of monitoring stations to be used

13.1.2 CONTRACTOR shall provide a detailed design specification for each

cathodic protection system as part of its detailed engineering
deliverables. This final specification shall contain, but not be limited to,
the following:

● Design philosophy, including protection criteria, design life, and

referenced codes and standards

● Results and assessment of site surveys

● Definition of the chosen cathodic protection systems (including

temporary systems), including selection, sizing, and placement with all
necessary calculations and economic justifications

● Evaluation of any potential stray current and interference effects, and

also impact from and to any neighboring secondary structures and
other cathodic protection systems

● List of all structures to be protected, including identification numbers,

locations, and dimensions

● List of all piping and pipelines to be protected, including identification

numbers, length, nominal diameter, coating and lining systems, pipe
specification, and service

● List of all isolating joints, including associated piping identification

numbers, service, type of joint, and calculations for sizing isolating
spool pieces

● List of all monitoring stations and junction boxes, including identification

numbers, location, and purpose

● List of all negative connection points, including identification numbers

and location

January, 2004 Specification EGP3-02.01 30 OF 30

 ● Detailed system layout drawings, indicating the location of anodes and
ground beds, transformer – rectifiers, cable routings, monitoring
stations, reference electrodes, negative connection points, and
adjacent secondary structures and neighboring cathodic protection
systems

● Definition of assigned IP ratings and Hazardous area classifications

13.1.3 The basic and detailed design specifications shall be produced by a

specialist cathodic protection engineer.

13.2 Installation and Commissioning Procedures

13.2.1 CONTRACTOR shall ensure that full installation and commissioning
procedures are submitted by the cathodic protection system design
CONTRACTOR, and that they are in accordance with the requirements of
this Project Specification and CONTRACTOR’s instructions.

13.2.2 Commissioning procedures shall contain, but not be limited to, the
information necessary to perform the tests and system balancing required
in this specification. CONTRACTOR shall submit these procedures for
COMPANY review and approval.

13.3 Operating and Maintenance Manuals

CONTRACTOR shall submit operating and maintenance manuals to COMPANY
as part of the hand-over documentation. These manuals shall contain, but not be
limited to, the following:

● A full description of each cathodic protection system as-installed, including as-

built drawings of the system layouts.

● Commissioning report, including a record of all measurements required.

● Maintenance procedures for all equipment items with recommended

schedules.

● Monitoring schedules and procedures for each monitoring station.

● Safe operating guidelines for the cathodic protection system.

● Schedule of recommended spares.

January, 2004 Specification EGP3-02.01 31 OF 30