Eni S.p.A.

Exploration & Production Division

COMPANY STANDARD

OFFSHORE PLATFORMS

CATHODIC PROTECTION MONITORING SYSTEM

FUNCTIONAL SPECIFICATION

20045.MAT.COR.FUN
Rev. 2 – October 2007

ENGINEERING COMPANY STANDARD

Documento riservato di proprietà di Eni S.p.A. Divisione Agip. Esso non sarà mostrato a Terzi né utilizzato per scopi diversi da quelli per i quali è stato inviato.
This document is property of Eni S.p.A. Divisione Agip. It shall neither be shown to Third Parties not used for purposes other than those for which it has been sent.
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PREMISE

Rev. 0 Not existing

Rev. 1 Sheets 28
March 1997

Rev. 2 Sheets 25
October 2007
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TABLE OF CONTENTS

1. INTRODUCTION
1.1 Premise
1.2 Scope
1.3 Reference normative
1.4 ENI Company normative
1.5 Definitions
1.5.1 General definitions
1.5.2 Technical definitions
1.6 Symbols and abbreviations
2. HEALTH, SAFETY AND ENVIRONMENTAL AND QUALITY REQUIREMENTS
2.1 Environmental Conditions
2.2 Health, safety and environmental regulations
2.3 Quality Assurance
3. FUNCTIONAL REQUIREMENTS
3.1 CPMS general configuration
3.2 CPMS detail design
3.2.1 Design life
3.2.2 Detail design package
3.2.3 Number of probes to be installed and positions
3.2.3.1 Reference cells
3.2.3.2 Instrumented anodes
3.3 CPMS components
3.3.1 Reference cells
3.3.1.1 Zinc reference electrode
3.3.1.2 Ag/AgCl reference electrode
3.3.2 Instrumented anodes
3.3.2.1 Isolating joints
3.3.2.2 Shunt
3.3.3 Underwater cables
3.3.4 Interconnection system
3.3.5 Protection box
3.3.5.1 Additional requirements for the protection box with temporary acquisition unit
3.3.6 Above water cables
3.3.7 Permanent CP monitoring unit
3.3.7.1 General
3.3.7.2 Cabinet
3.3.7.3 Data acquisition unit
3.3.7.4 Unit for the regeneration of zinc RC
3.3.8 Temporary acquisition unit (optional)
3.4 Installation
3.4.1 Installation in the yard
3.4.2 Installation after positioning of the deck
3.5 Testing
3.5.1 General
3.5.2 Testing at factory
3.5.2.1 Reference electrode calibration
3.5.2.2 Pressure test of the reference cells
3.5.2.3 Data acquisition and zinc regeneration units
3.5.2.4 Certificates
3.5.3 Testing at yard
3.5.4 Offshore Tests
3.6 Commissioning and start-up
3.7 Documentation
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1. INTRODUCTION

1.1 Premise

The present Document deals with the permanent monitoring systems to be installed on steel offshore
platforms to monitor the performance of the cathodic protection (CP) system.

CP of steel jacket is normally performed by aluminium alloy galvanic anodes; impressed current
systems are adopted in few cases only, in particular for CP retrofitting of already in service
structures.

The aims of the cathodic protection monitoring system (CPMS) are:

– to verify the performance of the CP system at any moment of the life of the platform;
– to periodically gather and record the operating data of the CP system.

CP monitoring as covered in this document is based on the installation on the steel jacket of
permanent reference cells for the reading of the steel potential and of galvanic anodes suitably
instrumented to allow the measurement of the delivered anode current.

1.2 Scope

This Specification provides the functional requirements for the supply of permanent systems for the
monitoring of cathodic protection of the immersed part of fixed steel offshore platforms, hereinafter
abbreviated as CPMS.

The document covers:

– the detail design minimum requirements of the CPMS;
– the requirements for the supply and installation of the components of the CPMS;
– the tests of the components of the CPMS.

The requirements covered in this Document are intended for all the Parties involved in a Project, i.e.
the Company, the Contractor and the Supplier, as defined at Par. 1.5.1.

1.3 Reference normative

ISO 1000 SI units and recommendation for the use of their multiples and of
certain other units.
EN 60947-1 Low-voltage switchgear and controlgear. Part 1: General rules.
EN 12473 General principles of cathodic protection in sea water.
EN 12495 Cathodic protection for fixed steel offshore structures.
EN 13509 Cathodic protection measurements techniques.
EN 60529 Degree of protection provided by enclosures.
DNV RP B401 Recommended Practice. Cathodic Protection Design.

1.4 ENI Company normative

27589.VAR.COR.PRG Guidelines for design and construction of cathodic protection

systems
06033.MAT.ELE.STD Underwater cables for offshore structure cathodic protection
monitoring system
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06034.MAT.ELE.STD Above Water Cables for Cathodic Protection Monitoring System,

Insulated with Polythene, Flame Retardant, for Rated Voltage up to
0,6/1 kV. Off shore Structures

1.5 Definitions

1.5.1 General definitions

COMPANY Shall mean Eni Div. E&P or its elected representatives.

CONTRACTOR Shall mean the company appointed by COMPANY to perform the

EPCI works of a package, and its subcontractors, vendors, agents
and authorised representatives.

PROJECT Any specific project to which the present Document applies.

SUPPLIER Shall mean the company that supplies the services and materials as
specified by COMPANY or CONTRACTOR and in accordance with
this Document.

For the purpose of applying this Specification to a contract or purchase order, the word “shall”
indicates a mandatory requirement; the word “should” indicates a recommendation.

1.5.2 Technical definitions

Instrumented anode the permanent device for measuring the anode current and
potential; it includes: an anode completed with isolating joints and
shunt, a reference cell; the relevant underwater cables.

Reference cell the permanent device for measuring the potential of steel structure;
it can include one reference electrode (single RC) or two reference
electrodes (dual RC).

Probe term to indicate one of the devices for CP monitoring, i.e. reference
cells and instrumented anodes.

1.6 Symbols and abbreviations

Ag/AgCl silver / silver chloride / sea water (reference electrode)

CP Cathodic Protection
CPMS Cathodic Protection Monitoring System
DCS Data Control System
EPCI Engineering, Procurements, Construction, Installation
RC Reference Cell
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2. HEALTH, SAFETY AND ENVIRONMENTAL AND QUALITY REQUIREMENTS

2.1 Environmental Conditions

The CPMS shall be designed in accordance with the Basis of Design of the Project.

All the components of the CPMS installed above water shall be designed to withstand the
environmental conditions as specified in the Design Premises of the Project.

The SUPPLIER shall review and confirm suitability of each component of the CPMS with respect of
the following environmental factors and aspects:
– minimum and maximum design temperature;
– minimum and maximum design pressures;
– formation of condensates;
– presence of corrosive species or pollutants;
– formation of moulds;
– electrical hazard;
– mechanical stress and vibrations during operation;
– electro-magnetic influence;
– explosion and fire hazard.

2.2 Health, safety and environmental regulations

The SUPPLIER shall be responsible for ensuring that materials and services supplied meet all
applicable regulations on health, safety and environmental issues.

The equipment shall be designed to operate safely and satisfactorily at all expected combinations of
process, utilities, climates and environmental conditions including those at start-up, shutdown, partial
load operation, and emergency cases while retaining the overall system security, reliability and
availability.

2.3 Quality Assurance

The SUPPLIER shall have in place a quality assurance organization responsible for formulating and
implementing a quality system, which ensures that the requirements of this specification are
achieved.

Unless otherwise stated in a purchase order, the SUPPLIER’s quality system shall be based on ISO
9000 (or COMPANY approved equivalent) and shall be described in a Quality Assurance Manual.

The Quality Manual and Quality Plan shall be submitted to COMPANY with the tender documents.
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3. FUNCTIONAL REQUIREMENTS

3.1 CPMS general configuration

The CPMS covered in this Document includes the following main components:
– probes: permanent reference cells and instrumented anodes, both installed underwater;
– interconnection system. It includes: conduits, protecting carters, joints, cable fixing devices to be
used for the installation of the monitoring cables;
– underwater monitoring cables;
– protection box, installed at the top of the jacket;
– junction box (or boxes);
– above water monitoring cables;
– the permanent CP Monitoring Unit for measurement reading and storing, installed above water
inside a conditioned environment (control room or equivalent);
– temporary Data Acquisition Unit (optional) for data acquisition after the lifting or launching of the
jacket and before availability of the permanent CP Monitoring Unit.

The reference cells and the instrumented anodes, installed in defined positions of the jacket, are
connected to the relevant underwater monitoring cables. The underwater monitoring cables,
protected by steel conduit all along their route, are conveyed to the protection box, installed at the top
of the jacket above water.

Inside the protection box, the junction box is installed (if needed, more than one depending on
number of cables to be routed inside); within the junction box the underwater cables are connected to
the relevant terminals. At same terminals the above water cables are connected, laid between the
junction box and the terminal board located inside the permanent CP Monitoring Unit. Signals are
then sent to the unit that performs the periodical readings and allows visualizing the positions of the
reference cells and of the monitored anodes and the corresponding values of potential and delivered
current in real time.

The logic diagram of typical CPMS is shown in Figure 3.1.

The installation of the CPMS is carried out in two phases:

– in the first phase, all the components to be mounted on the jacket, i.e. the probes with underwater
cables, the conduits and accessories, the protection box, are installed, This occurs in the yard
before launching of the jacket;
– the second phase is planned after installation of the deck: the protection box is open and the
junction box installed; the underwater and above water cables are wired inside the junction box
and the above water cables laid up to the permanent CP Monitoring Unit;

the commissioning and start up of the CPMS are performed at the completion of the installation of all
the components and once electrical power is available.

The system above illustrated provides information about the performance of the CP system only after
commissioning of the whole system, which normally occurs a few months after launching of the
jacket. This is acceptable for most project; however, in case information on polarization of the
submerged structure and on anode performance are needed from the moment the jacket is
launched, the above described system is integrated with the temporary acquisition unit, operating
with its own batteries, and designed to start recording immediately after the launch of the jacket. The
temporary acquisition unit is accommodated within the protection box.

In this document the temporary acquisition unit is intended as optional, and to be provided only in
case it is requested in the Project Documents.

NOTE. In case of small size jackets, like for instance monopods of shallow water platforms, a
simplified version of the CMPS can be proposed for approval to the COMPANY that does not include
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the instrumented anodes and permanent CP monitoring unit. In that case, reading and recording of
the potential value from reference cells shall be performed manually by operators.

permanent CP
monitoring Unit

above-water cables

protection box junction box

under-water cables

isolating joint
isolating joint c/w shunt

instrumented
anodes

reference cells

Figure 3.1 – CPMS logic diagram.

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3.2 CPMS detail design

3.2.1 Design life

The CPMS shall be designed to have a minimum operating life equal to the design life of the cathodic
protection system.

A design life greater than at least 30 years is in any case recommended.

3.2.2 Detail design package

A detail design package shall be issued of the CP monitoring for each Project and each platform.

The detail design package shall include:

– CP monitoring specification covering:
− the philosophy of CP monitoring based on the feature of the steel jacket and CP system
and in accordance with this Document;
− the type of probes to be adopted;
− for each type of probe – reference cell and instrumented anode – the number to be installed
and their location;
– the drawing showing the position of the probes;
– the drawing showing the installation details; these will include:
− probe installation details;
− cable/conduit routes (plan and elevations);
− all the details of the interconnecting system;
– specification and datasheets of all the components of the CPMS.

All the components of the CPMS shall be designed to not interfere with any operation of installation
of the jacket, including the pile and conductors driving.

3.2.3 Number of probes to be installed and positions

3.2.3.1 Reference cells

The number of reference cells to be installed on a single jacket and the relevant positions shall be
defined for each Project in accordance with the minimum requirements defined in this Document.

For platforms located in water depth up to 100 m, N. 1 reference cell minimum shall be foreseen
each 500 m2 of bare steel surface area exposed to sea water.

For greater depths, the number of reference cells shall be defined as part of the detail design and
approved by the COMPANY.

The reference cells shall be located preferably on plans.

On each plan a minimum of N. 2 reference cells shall be installed.

N. 4 reference cells minimum shall be foreseen for each jacket.

A reference cell shall be installed in close proximity (less than 0.5 m) of each instrumented anode.

Reference cells shall be preferably installed in shielded and crowded location positions, where lower
polarization values are expected. These include, for instance: proximity to nodes; proximity to
conductors.
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In any case the position of the cells and the route of conduits shall be chosen taking into account that
the structural members of the jacket shall be regularly inspected. Such inspections will be carried out
in areas adjacent to circumferential welds connecting members to joints. Such areas shall not be
obstructed in order to facilitate inspections.

3.2.3.2 Instrumented anodes

Installation and number of instrumented anodes as part of the CPMS shall be defined in detail design
phase of each Project.

The following guidelines are provided about installation of instrumented anodes.

– For shallow water platforms, i.e. located in waters less than 40 m deep, installation of
instrumented anodes is not mandatory.
– For platforms located in waters from 40 m to 80 m deep, N. 2 instrumented anodes as a minimum
shall be installed, preferably in the deepest part of the structure.
– For deep water platforms, i.e. located in waters deeper than 80 m, N. 4 instrumented anodes as a
minimum shall be installed, preferably in the deepest part of the structure.

3.3 CPMS components

3.3.1 Reference cells

The following types of RC are applicable for potential measurements:

– single RC, with zinc as reference electrode;
– dual RC, with zinc and silver/silver chloride (Ag/AgCl) as reference electrodes.

The single RC with Ag/AgCl reference cell is not admitted.

Use of dual type reference cells shall be preferred with respect to single RC.

Use of dual type reference cells is mandatory for deep water platforms, i.e. located in waters deeper
than 80 m.

The RC’s, single or dual, shall be designed with a metallic frame, completely sealed with resin, and
suitable for being welded to the structure in the yard.

Sealing between the steel frame of the RC and the underwater cable shall be provided by:
– cable gland with O-ring or equivalent system;
– resin.

The type of resin shall be selected to provide adherence to the external sheath of the underwater
cables as well as to the steel frame.

Single RC shall be supplied connected to an underwater cable with N. 2 isolated conductors: one
connected to the zinc element and one to the steel frame to be welded to the structure. Dual RC shall
be supplied connected to an underwater cable with N. 4 isolated conductors: one couple for the zinc
reference electrode and another for the Ag/AgCl reference electrode.

Each RC shall be assembled with a cable long enough to reach the protection box without any
intermediate joint.

The position of the RC support shall be at least 200 mm far from every primary structural connection,
such as longitudinal and circumferential welds.

Each RC shall be identified by a tag made of bronze or other material suitable for seawater
exposure. The tag shall be adequately fixed to the steel frame.
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3.3.1.1 Zinc reference electrode

The zinc RC shall be manufactured using high purity zinc, fulfilling the following composition
requirements:
– Zn, 99.99 % min.
– Fe, 0.005 % max.
– Cu, 0.005 % max.
– Pb 0.006 % max

The zinc element, once assembled into the steel frame, shall have a minimum surface in contact with
sea water of 300 cm2.

The mass of the zinc element exposed to sea water (i.e. excluding the part encapsulated into the
frame) shall be of 4.0 kg minimum. Furthermore, the supplier shall verify that the zinc consumption
due to the regeneration procedure (see Par. 3.3.7.4), assumed to be performed each month all along
the design life) would not consume more than 50 % of the mass of the zinc element exposed to sea
water.

An underwater cable with N. 2 isolated conductors will be foreseen for single RC. The two
conductors will be connected one to the zinc element and one to the steel frame to be welded to the
structure.

3.3.1.2 Ag/AgCl reference electrode

The Ag/AgCl reference electrodes shall be built from a high purity silver (Ag) element on which high
purity silver chloride (AgCl) is deposited.

The AgCl deposition method shall be specified in the Documentation issued by the Supplier and it
shall guarantee a durability equal to the design life of the CPMS.

The electrode shall be enclosed in a suitable non metallic enclosure allowing free contact with sea
water and protecting the reference electrode mechanically and from light (AgCl being
photosensitive). Then, the electrode completed with plastic enclosure shall be assembled into a steel
frame.

An underwater cable with N. 2 isolated conductors will be foreseen for single RC. The two
conductors will be connected one to the silver element and one to the steel frame to be welded to the
structure.

3.3.2 Instrumented anodes

Instrumented anodes are installed with the aim to measure the anode current output and the anode
potential.

For a given Project, the instrumented anodes shall be taken from the lot of the anodes supplied for
cathodic protection of the jacket and shall be in accordance with the applicable normative for
galvanic anodes.

Each instrumented anodes shall be equipped with:

– N. 2 isolating joints, to be assembled on the anode support, at each side of the anode;
– a calibrated shunt, properly assembled into one of the two isolating joints to short-circuit it;
– a reference cell to be installed in close proximity;
– underwater cables.

The isolating joints and the shunt shall resist with no damage during the operation of welding of the
anode to the structure. If needed, advice shall be provided by Supplier.
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For each instrumented anode, a reference cell shall be foreseen to be installed on the jacket in close
proximity to the anode itself. For each Project, the reference cell of the instrumented anodes shall be
of same type installed on the jacket.

3.3.2.1 Isolating joints

The isolating joint shall have a minimum resistance of 5 MΩ and adequate dimensions to be installed
on the supports of the anodes.

The original support of the anode to be instrumented shall be cut to insert the joint. This shall be
positioned in a way that the further welding operations on the structure cannot cause any problem to
the measurement equipment installed in it.

3.3.2.2 Shunt

The shunts to be used in the monitoring of the current emitted from the anodes shall have a gauged
resistance of 5 ± 0.1 mΩ and shall be sized based on expected circulating current and shall have
adequate dimensions to be installed inside the isolating joints.

3.3.3 Underwater cables

Underwater cables connecting the probes to the junction box shall conform to requirements specified
in the Company Document 06033.MAT.ELE.STD.

The configuration of the cable conductors shall be:

– single RC: N. 2 conductors each 1.5 mm2 minimum;
– dual RC: N. 4 conductors each 1.5 mm2 minimum.

Each reference cell and instrumented anode shall be assembled with a quantity of cable long enough
to reach the protection box without any intermediate joint. An extra length of 5 m minimum shall be
added for each cable.

On protection box, cables ends shall be insulated in the yard with heat shrinkable sleeve caps (with
sealant) to avoid cable flooding in launch operations.

3.3.4 Interconnection system

The interconnection system, from probes to the protection box, includes the underwater cables,
conduits, caisson, protection carter (see Figure 3.2).

The cables shall run inside the protection conduits along the members and joints of the
corresponding plan of the jacket, up to a single ascending caisson-manifold. The caisson shall
protect cables in their route up to the protection box.

The construction material for conduits pipes, the relevant joints and the caisson shall be carbon and
low alloy steel.

The cable conduits shall be fixed by welded supports (see Figure 3.4) to the structure and shall be
conveniently shaped near the joints and structures with complex geometry. The conduit pipes shall
be jointed through connection joint spools (see Figure 3.4) and shall be interrupted in adequate
positions to facilitate the installation and pull of cables, that is, near bends or after around 10 m of
rectilinear segment. Protection carters shall be provided in these interruption points (see Figure 3.5).
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Connection boxes shall be provided between conduits (see

Figure 3.6).
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The conduits shall be designed taking in consideration the number of cables that shall contain (see
Figure 3.4).

The underwater cables shall be protected all along the length from the reference cell or instrumented
anode up to the protection box. Flexible joints shall be provided for the final connection between
metal conduits, installed on the structure, and each reference cell or instrumented anode.

3.3.5 Protection box

The protection box is a carbon steel box located in the upper part of the jacket, preferably in
correspondence with the upper plan of the jacket, in a position that guarantees its accessibility after
deck installation. It provides protection to the underwater cables coming from the caisson launch and
installation operations of the Jacket.

Inside the protection box, the supports shall be installed for the junction box to be fixed after erection
of the deck.

The sizes of the protection box shall be designed to contain the ends of the underwater cables (5 m
each) to be further wired into the junction box.

The protection box shall be identified through a tag made of stainless steel.

The protection box shall be painted preferably with the same cycle of painting provided for the jacket
in correspondence to the splash zone or with same cycle specified for structural steel elements of the
deck.

The connection system of the protection box with the jacket shall be defined in an agreement with the
Company and shall be such as to withstand the operations of fabrication and installation of the
jacket, with main reference to the launch and the pile driving, and to allow for an easy execution of
these operations.

3.3.5.1 Additional requirements for the protection box with temporary acquisition unit

In case a temporary acquisition unit (see Par. 3.3.7 in this Document) shall be installed, the
protection box shall guarantee seal protection against entry of sea water during the launch of the
jacket.

The temporary acquisition unit shall be conveniently fixed into the protection box or preferably into
the junction box, in this case previously assembled in the yard.

Depending on impact resistance properties of the temporary acquisition unit, vibration dumpers shall
be installed to absorb the impacts due to pile driving. The stress approximate values are the
followings:
– vibrations: 5 ÷ 100 Hz, 2g;
– shocks: 20 g, 6 milliseconds ½ sinusoidal.

3.3.6 Above water cables

Above water cables connecting the junction to the permanent CP monitoring unit shall conform to
requirements specified in the Company Document 06034.MAT.ELE.STD.

Number of cores shall be defined in the detail design documents based on number of installed
probes.

3.3.7 Permanent CP monitoring unit

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3.3.7.1 General

The permanent CP monitoring unit consists of the following main components:

– cabinet, installed inside a conditioned environment like the Instrument Equipment Room, sized for
19" electronic racks;
– terminal boards;
– data acquisition unit; in its preferred version it is an industrial personal computer with accessories
as specified, and with dedicated software programs;
– unit for the regeneration of zinc RC.

All components shall withstand to impact and vibrations loads of the deck during transportation,
installation and to operative conditions.

3.3.7.2 Cabinet

The cabinet of the permanent CP monitoring unit shall contain all the components of the unit.

The cabinet shall be sized for sized for 19" electronic racks.

Cables shall enter into the cabinet from the bottom. The terminal boards shall be located in the lower
part of the cabinet.

Separate terminal boards shall be foreseen for zinc and silver - silver chloride reference electrodes.

The protection degree as per EN 60529 shall be defined in the detail design phase based on the
location of the cabinet.

3.3.7.3 Data acquisition unit

The hardware and software of the data acquisition unit shall be suitable for data processing,
recording and measuring.

The values of potential from the reference cells and of anode current from instrumented anodes shall
be recorded in the memory of the unit.

The unit shall allow an operator to periodically unload the data stored in the memory by the portable
personal computer, using appropriate software. The unloading can be allowed also through a serial
link to DCS (Data Control System) if foreseen.

The unit shall be capable of working in a completely automatic way, recording the measurements
from the probes, for at least 12 months.

The unit shall be programmable via software only.

The electronic will include:

– a minimum number of channels equal to the number of reference cells and instrumented anodes
plus N. 5 channels spare minimum;
– an amplifier with programmable gain via software;
– A/D converter;
– real-time clock microprocessor;
– resident industrial personal computer, keyboard and monitor;
– programme memory and data memory (RAM);
– RS-232-C serial interface for portable personal computer;
– RS-485 serial interface for DCS (optional);
– back-up battery.
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All any other equipment and/or device required to meet the functional requirements of the CPMS
shall be indicated and provided by the SUPPLIER.

The minimum requirements of the electronics of the data acquisition unit shall be:
– nominal range of the channels used to record the data coming from the instrumented anodes:
0.00 A / 10 A
– accuracy on above channels: ± 2 mV for potential measurements and ± 0.04 A for current
measurements;
– operating temperature: -10°C/+65°C;
– nominal range for the channels used to record the data coming from the Ag/AgCl electrodes: 0
mV/ -2000 mV;
– nominal range for the channels used to record the data coming from the zinc electrodes: +1000
mV/ -1000 mV;
– acquisition interval: programmable via software from a minimum of 1 minute;
– A/D converter suitable to satisfy the precision required to the sensors;
– storage capacity: suitable to guarantee the CPMS working criteria, as they are defined in this
specification without any loss of data;
– entry impedance: 10 Mohm minimum;
– watch error: it shall not exceed 5 minutes on 6 months and shall be adjustable during the
periodical visits to the platform;
– thermal drift: less than 3 mV/°C (data acquisition part);
– "hardened" type electronics and at low energy consumption;
– galvanically insulated entries;
– the data memory shall have back-up lithium cells that guarantee at last 3 years data storage in the
absence of any battery supply.

The resident software shall carry out the following main functions:
– data acquisition;
– organization and storage;
– processing of the signal coming from the shunts;
– management of the CPMS drawings;
– interface towards an operator connected via resident personal computer or DCS.

The processing of tension signals coming from the shunts of the monitored anodes shall be executed
by the data acquisition unit so that the value of the current emitted may be recorded.

The data acquisition unit shall record an identification header of more data organized in time series.
The identification general header shall always be transmitted to the permanent personal computer or
DCS. The identification general header shall contain two data series that shall be automatically
generated by the data acquisition unit or possibly be inserted in the data acquisition unit by an
operator via the management software. The same software shall carry out the automatic saving of
the information transmitted to the operator.

The first series of data will concern:

– the name of the platform;
– the CPMS supplier name;
– the alphanumerical identification code of reference cells (the same reported on the tags) and of
monitored anodes.

The second series of data concerns:

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– the parameters of the measurement and of the recording;

– the number of time series collected after the last data unloading operation;
– reference cell and reference electrode type.

The data acquisition unit shall record data organized in time series. Each time series shall consist of:
– a series header containing a progressive number which identifies the time series, date and time
(serial number; year; month; day; hour; minutes);
– the potential values read by the single reference cells and the values of current delivered by the
monitored anodes.

The software shall also allow to define the data acquisition, in a user-defined time interval, to have
the memorization of all the measurements (basic option), but also the memorization of minimum
values, or maximum values, or medium values, or of minimum, medium and maximum values at the
same time.

In order to facilitate processing and interpretation of the data organized in time series, the data files
stored in the memory shall be compatible with electronic spread sheets or with database operating
on a Windows graphic platform of Microsoft Corporation.

The software shall allow the operator to effectively interface with the CPMS and to easily test the
correct performance of the system.

The CPMS shall also have capabilities of self diagnosis for at least a small number of functions (i.e.
lack of supply, potential value of a reference cell or current delivered value of an instrumented anode
reasonably out of range) and shall be capable of communicating anomalies.

3.3.7.4 Unit for the regeneration of zinc RC

The zinc reference cell can provide incorrect potential readings if covered by corrosion products or
marine fouling. However, the cell can be easily regenerated by temporary circulation of a continuous
anodic current designed to clean the electrode thus exposing a new metallic surface to sea water.

The regeneration shall be performed by a dedicated unit, controlled by a software program, which
perform the regeneration according to the following parameters:
– current density: 3 ÷ 5 mA/cm2;
– duration: 15 minutes;

The regeneration unit shall control the circulation of the DC current between the zinc electrode and
the structure through a circuit that uses the cable connecting the cell to the permanent CP monitoring
unit. The circuit will include a DC power source with maximum voltage indicatively of 20 V and a
resistance whose size shall be designed based on sizes of the exposed zinc element.

The regeneration of each zinc reference cell shall be performed:

– automatically, with frequency of a regeneration process every month;
– manually, on request of the operator.

3.3.8 Temporary acquisition unit (optional)

The temporary acquisition unit shall be installed only in case it expressively requested by the
COMPANY.

It is an electronic instrument lodged in the protection box whose function is to record the data from
reference cells and instrumented anodes in the period from launch of the jacket to the start uo of the
permanent CP monitoring unit.
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The electronic and software of the temporary acquisition unit shall be suitable for data processing,
recording and measuring. The values of potential and current emission data shall be recorded in the
memory. The stored data shall then be recovered by an operator connecting the temporary
acquisition system itself to the serial door of a portable computer using appropriate menu software.

The temporary acquisition unit shall be capable of working in a completely automatic way, recording
the data acquired by the sensors, for at least 6 months without any need to be fed by an external
source.

The programming of the temporary acquisition unit shall be carried out via software only, by
connecting it to the serial door of a portable personal computer.

The temporary acquisition unit shall have an appropriate number of channels and an amplifier with
programmable gain via software; A/D converter; real-time clock microprocessor, programme memory
and data memory (RAM); RS-232-C serial interface for personal computer; work battery with battery
monitoring circuits, back-up battery.

3.4 Installation

3.4.1 Installation in the yard

The installation of RC and instrumented anodes with relevant cables is performed in the jacket
fabrication yard.

Each RC and instrumented anode is first positioned and fixed on the member where it must be
welded; then cables are routed into the protection conduits previously installed and pulled until they
reach the protection box situated on top of the jacket.

The RC and the instrumented anode shall be installed having the cable glands as close as possible
to the terminal part of the conduit, therefore reducing the length of the flexible conduit which protects
the last part of the cables to the minimum.

The mounting and welding procedure of the probes shall not damage the probes themselves and
their components (electrodes, shunt, isolating joint).

3.4.2 Installation after positioning of the deck

After the installation of the deck, the following works shall be performed:
– opening of the protection box;
– laying of the above water cables and wiring to the terminal board in the junction box inside the
protection box;
– installation of the permanent CP monitoring unit if not already installed onshore;
– wiring to the terminal boards located in the cabinet of the permanent CP monitoring unit.

3.5 Testing

3.5.1 General

Testing of the CPM system shall be carried out:

– at the factory of the Supplier;
– at the jacket fabrication yard;
– on platform.

3.5.2 Testing at factory

3.5.2.1 Reference electrode calibration

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Calibration shall be performed after complete assemble of the cells, with the underwater cable
connected.

The test shall be performed in accordance with the Suppliers calibration procedures. Measured
potential for each reference cell shall be reported in the Calibration Certificate, where the testing
procedure and the used laboratory reference electrode shall be indicated.

3.5.2.2 Pressure test of the reference cells

Calibration shall be performed after complete assemble of the cells, with the underwater cable
connected.

The pressure test shall be performed in accordance with the Suppliers calibration procedures and
with the following requirements:
– the pressure test shall be 1.5 time the hydrostatic pressure corresponding to the maximum water
depth for the Project under study;
– pressure shall be maintained for at least 24 hours;
– at the end of the test a visual inspection shall be performed of the reference cell and of the free
terminal of the underwater cables to exclude that any water entrainment was occurred; electrical
isolation shall be verified between the reference electrode and the corresponding cable core.

Pressure tests shall be performed:

– for platforms installed waters more than 80 m deep: on all the reference cells;
– for platforms installed waters less than 80 m deep: on a sample of at least 2 (two) reference cells
extracted form the lot of the reference cells to be installed on a platform.

3.5.2.3 Data acquisition and zinc regeneration units

The data acquisition unit, the temporary acquisition unit, if foreseen, and the zinc RC regeneration
unit shall be tested at factory to verify their integrity and correct functionality.

Simulated electrical circuits shall be used to verify the correct readings for each channel and the
regeneration unit.

A suitable testing procedure shall be issued by the Supplier.

3.5.2.4 Certificates

The following certifications shall be issued, as a minimum, by the Supplier before shipping:
– compliance certificate of all the components to the Project Documents including this Specification;
– calibration test certificates of all the reference cells;
– pressure test certificates, if performed;
– data acquisition and zinc regeneration units factory test certificates.

3.5.3 Testing at yard

The following tests and inspections shall be carried out in the jacket fabrication yard after the
installation of the CPMS components:
– check of conformity with the Project Documents (drawings, specifications, etc.);
– visual inspection of all the installed reference cells and relevant cables to assess their integrity
and absence of any damage;
– check of the underwater cable routes and connections to the protection box and junction box;
– electrical isolation test to be performed on the instrumented anodes, after their installation, to
verify the electrical isolation between the anode and the steel supporting element of the jacket.
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A test certificate covering all above tests and inspections shall be issued.

3.5.4 Offshore Tests

The following tests and inspections shall be carried out on platform after complete installation of the
CPMS:
– check of cable routes and connections between the junction box and the data acquisition unit
cabinet;
– functionality test of the data acquisition unit and of the zinc regeneration unit.

A procedure for offshore tests and commissioning (see Par. 3.6) shall be proposed by
Supplier/Contractor and approved by the Company.

3.6 Commissioning and start-up

The commissioning of the CPMS shall be performed in accordance with a Commissioning

Specification to be issued by the Supplier of the CPMS.

As part of the commissioning the following activities shall be performed:

– reading and recording of the potential of the structure with respect to all the permanent cells;
– reading and recording of the potential and of the current of all the instrumented anodes;
– repolarization of all the zinc reference electrodes.

3.7 Documentation

A CPMS Documentation Package shall be issued by Supplier / Contractor including:

– CPMS project specifications and drawings (as built);
– Functional and wiring diagrams;
– Data sheet of all the main components;
– Testing documentation;
– List of spare parts;
– Procedure for commissioning, start-up and operation;
– CPMS operating manual, including maintenance requirements.
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PROTECTION BOX

CAISSON 6"-8"-10"

A
SPOOL FLEXIBLE CONDUIT
REFERENCE CELL

CONDUIT 2"- 3"- 4"- 6"

A

PROTECTION CARTER

PROTECTION CARTER

CONDUIT CONNECTION BOX

Figure 3.2 – Interconnection system. Assembly.

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STAUFF TYPE HOLDER STAUFF TYPE HOLDER

OR EQUIVALENT TYPE OR EQUIVALENT TYPE

CONDUIT 2" D.N. CONDUIT 3" D.N.

CONDUIT 2" D.N. CONDUIT 3" D.N.

STAUFF TYPE HOLDER

OR EQUIVALENT TYPE STAUFF TYPE HOLDER
OR EQUIVALENT TYPE

CONDUIT 4" D.N. CONDUIT 6" D.N.

CONDUIT 4" D.N. CONDUIT 6" D.N.

STAUFF TYPE HOLDER

OR EQUIVALENT TYPE

R18 R=4

CONDUIT

CONDUIT 8"/ 10" D.N.

CONDUIT 8"/ 10" D.N.

Figure 3.3 – Conduit cable holders. Details.

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CONDUIT SUPPORTS

CONDUIT '1' CONDUIT '2'

CONDUIT

CONDUIT '1' CONDUIT '2' PIPE N.D. x th.

2" 2" 88.9 x 7.62
3" 3" 114.3 x 7.92
4" 4" 168.3 x 21.95
6" 6" 219.1 x 20.6

Figure 3.4 – Conduit supports and joint spool. Details.

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CONDUIT '1' CONDUIT '2'

FORO

PIPE ND x Th.

CONDUIT '1' CONDUIT '2'

PIPE ND x Th.
D.N. HOLE D.N. HOLE

2" 62 2" 62 168.3 x 5.06

3" 91 3" 91 168.3 x 5.06

4" 116 4" 116 219.1 x 5.46

6" 170 6" 170 273 x 5.56

8" 221 8" 221 323.8 x 6.35

10" 275 10" 275 406.4 x 7.92

Figure 3.5 – Protecting carter. Details.

Eni S.p.A. 20045.MAT.COR.FUN
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HOLE

A A
SECTION A-A

B B

SECTION B-B

HOLE

C C

SECTION C-C

D D

SECTION D-D

Figure 3.6 – Connecting conduits boxes. Details.