Commissioning and Operation of Cathodic Protection Systems of Plant Facility Structures

1. SCOPE ……………………………………………………………………………………2. REFERENCE ……………………………………………………….3. DEFINITIONS……………………………………………………….4. GENERAL REQUIREMENTS …………………………..
4.1. Health and Safety ……………………………………………………….4.2. Supervision ……………………………………………………….4.3. Quality Assurance System …………………………..
5. CRITERIA ……………………………………………………….5.1. Protection Criteria ……………………………………………………….5.2. CP System Acceptance Criteria …………………………..
6. COMMISSIONING AND CP ADJUSTMENT …………………………..6.1. Pre-Commissioning Testing and Inspection …………………………..6.2. Pre-Energizing Measurements …………………………..6.3. Initial Energizing and Current Adjustment …………………………..6.4. Initial Performance Assessment…………………………..6.5. Adjustment of Current Output …………………………..
7. SYSTEM RECORDS AND DOCUMENTATION …………………………..7.1. Quality and Test Records ……………………………………………………….7.2. Installation & Commissioning Report …………………………..7.3. Operation and Maintenance Manual …………………………..7.4. Submittals and Completion Dates …………………………..
8. OPERATION AND MAINTENANCE …………………………..8.1. System Operation ……………………………………………………….8.2. System review report. ……………………………………………………….8.3. Long Term Operation ……………………………………………………….
9. APPENDIX A ……………………………………………………….10. APPENDIX B ……………………………………………………….11. APPENDIX C ……………………………………………………….

1. SCOPE

This specification establishes the minimum requirements for the commissioning, operation
and maintenance of impressed current cathodic protection (ICCP) systems and sacrificial
anode cathodic protection systems (SACP) for plant facility structures. This standard shall be
read and applied in conjunction with L02-E01.
2. REFERENCE

Reference is made in this standard to the following documents. The latest issues,
amendments and supplements to these documents shall apply unless otherwise indicated
SABIC Engineering Standards (SES)

L02-E01 Cathodic Protection of Plant Facility Structures.
3. DEFINITIONS

For the purpose of understanding this standard, the following definitions apply.
ANODE – The electrode at which oxidation reactions (i.e. corrosion reactions) occur. For
cathodic protection of plant facility structures, the anode is used to distribute protective
current to the metallic structure.
CATHODE – The electrode at which reduction reactions occur. In a cathodic protection
system for plant facility structure, the cathode is the metallic structure.
CONSTANT CURRENT CONTROL – Mode of operation of a transformer rectifier to provide
constant current output. In this operation mode, drive voltage automatically adjusts with
changes in the circuit resistance to provide constant current.
CONSTANT VOLTAGE CONTROL – Mode of operation of a transformer rectifier to provide
constant voltage output. In this operation mode, current automatically adjusts with changes in
the circuit resistance to provide constant voltage.
CURRENT-ON POTENTIAL – The potential of the metallic structure measured by the
reference electrode when the cathodic protection system is in operation, i.e., with cathodic
protection current flowing. This potential includes the polarization potential and any other
voltage drops resulting from the flow of current (IR drop).
ELECTRODE POTENTIAL – The measured potential of an electrode in an electrolyte relative
to the potential of a reference electrode.
ELECTROLYTE – A liquid, or the liquid component in a composite material such as soil or
water, in which electric current may flow by ionic charge transfer.
EMBEDDED REFERENCE ELECTRODE – A reference electrode which is permanently fixed
within the electrolyte close to the metallic structure but not touching it.
ENERGIZING – The process of the initial application of power to the cathodic protection
system.
IMPRESSED CURRENT – Direct current supplied by an external power source to
cathodically protected structure.
INSTANT-OFF POTENTIAL – in order to measure the true polarized potential, the potentials
are measured with the current turned off instantaneously, thus eliminating the IR drop (see
CURRENT-ON POTENTIAL above).
INTERRUPTER – A timing device that permits a cyclic off/on interruption to the flow of
cathodic protection current.

NATURAL POTENTIAL – Corrosion of the structure occurs when there is a net flow of
electrical current between one part of the structure and another. This tendency to corrode
can be measured with a voltmeter and a reference electrode and is called the “natural
potential” or “corrosion potential”.
POLARISATION – When the cathodic protection system is in operation, there is a net flow of
electrical current between the anodes and the metallic structure. As a result of that current
flow metallic structure/electrolyte potential is shifted towards more negative potentials. This
potential shift from their open circuit corrosion potentials is called “ polarization”. This
polarization potential can be varied by varying the current flow in the cathodic protection
system. Accordingly, a desired level of corrosion protection can be selected.
REFERENCE ELECTRODE – A half-cell of reproducible potential, such as copper-copper
sulfate (Cu/CuSo4 ) and silver-silver chloride (Ag/AgCl). A standard against which potentials
or other electrodes can be measured or compared. Reference electrodes may be portable or
permanently installed in the electrolyte.
SYSTEM NEGATIVE CONNECTIONS – Cables electrically connected to the metallic
structure in the concrete. These cables are connected to the negative terminals in the
rectifier.
TRANSFORMER RECTIFIER – A device used to convert alternating current to direct current.
In a cathodic protection system, the transformer rectifier is used to control the voltage, current
or potential to each CP system.

4. GENERAL REQUIREMENTS

In addition to the above standards, referenced in section 2, the anode manufacturer‟s own
recommended installation/materials standards and procedures shall be recognized as part of
this standard. No deviations from that recommended, and/or quality standards shall be
permitted without prior written agreement by SABIC.

4.1. Health and Safety

All work associated with cathodic protection of underground metallic structures shall be
undertaken in compliance with the SABIC Affiliate (Plant) Health and Safety Procedures,
SASO‟s SSA 336 and OSHA‟s 29 CFR 1910 and 1926. Work permits shall be obtained from
respective authorities when necessary.
4.2. Supervision

The cathodic protection of metallic structure requires expertise in the field of electrochemistry,
electrical, structural engineering and cathodic protection engineering.
4.2.1. The engineer supervising the cathodic protection system‟s pre-commissioning, energizing,
commissioning and long-term operation and maintenance, shall be a Cathodic Protection
tester with NACE approved training. The engineer‟s professional experience should be
minimum 5 years in cathodic protection of underground metallic structures.

4.3. Quality Assurance System

4.3.1. Each stage of the CP system commissioning, initial energizing, and long-term operation &
assessment shall be fully documented and recorded in accordance with ANSI/ASQC Q9001
quality assurance plan.
4.3.2. Appropriate visual and mechanical or electrical testing, or both, shall be carried out for every
stage of the pre-commissioning checks (circuit verification), initial energizing, long-term
operation & assessment and maintenance. Testing shall be documented.
4.3.3. Test instruments shall have valid calibration certificates traceable to international standards
of calibration.
4.3.4. The quality documentation shall constitute part of the permanent record of the works.

5. CRITERIA

5.1. Protection Criteria

Any representative monitoring point shall meet the following criteria:

a. An instant off potential (measured between 0.1 s and 1 s after switching the DC
circuit open) more negative than -850 mV and less negative than -1,200 mV with
respect to a saturated copper/copper sulphate (Cu/CuSO4
) reference electrode.
b. An instant off potential (measured between 0.1 s and 1 s after switching the DC
circuit open) more negative than -800 mV and less negative than -1,150 mV with
respect to a silver/silver chloride (Ag/AgCl/Sat. KCl) reference electrode.
c. Where anaerobic bacteria are active, an instant off potential (measured between
0.1 s and 1 s after switching the DC circuit open) more negative than -950 mV and
less negative than -1,300 mV with respect to a saturated copper/copper sulphate
(Cu/CuSO4) reference electrode or more negative than -900 mV and less negative
than -1,250 mV with respect to a silver/silver chloride (Ag/AgCl/Sat. KCl) reference
electrode.

d. For tank internal only, ON potential shall be more negative than -900 mV and less
negative than -1,250 mV with respect to silver/silver chloride (Ag/AgCl/Sat. KCl)
reference electrode. This criterion is only applicable to tank internal when protected
by sacrificial anode cathodic protection system. For tank internal protected by
impressed current cathodic protection system, follow the first two criteria mentioned
above.

5.2. CP System Acceptance Criteria
The criteria for the acceptance of CP systems at different stages shall be as follows:

Stage 1: Commissioning & 30 Day Performance Verification Acceptance
30 days after initial energizing of the CP system, the system commissioning and performance shall
be considered satisfactory and verified if it meets the following criteria:
The specified criteria (as given above in 5.1) are met at 80% of the monitoring locations
(permanent and portable reference electrodes) in each independently powered CP system.
Note:
If the above criteria is met then the system shall be deemed commissioned and the 12 month
monitoring period shall commence. If the above criterion is not met then the current shall be
increased in the area which did not meet the criteria and left for agreed period of time with SABIC
Engineer (typically 3 to 7 days). After agreed time period has elapsed second performance
verification shall be conducted. If no further adjustments are required after this time, the
performance verification will be certified as acceptable and the date of submission of the
performance verification shall be considered as completion of the commissioning of the CP system.

Stage 2: 12-Month System Performance Assessment & Final Acceptance
The CP system shall be accepted only if its performance assessment meets the following criteria:
The specified protection criterion (as given above in 5.1) is met at all (100%) monitoring locations.

6. COMMISSIONING AND CP ADJUSTMENT

6.1. Pre-Commissioning Testing and Inspection

6.1.1. Impressed Current Cathodic Protection System.

Appendix A provides typical forms (Forms 1 to 5) for CP system circuit verification. These
forms are examples for testing and inspection data recording. These example forms can be
modified for specific requirements.
6.1.2. Prior to energizing, the following inspection and testing shall be conducted as a minimum:
a) Power supplies shall be inspected, to verify AC input and DC output
connections. Mechanical fasteners shall be inspected, tightened, or replaced
if required.
b) Correct polarity shall be verified for all circuits. Test results shall be recorded
on Form 5, Appendix A.
c) Continuity of the anode circuits shall be tested and verified. Test results shall
be recorded on Form 1, Appendix A.
d) Discontinuity between positive and negative circuits shall be tested and
verified. Test results shall be recorded on Form 4, Appendix A.
e) Continuity of negative circuits shall be tested and verified. Test results shall
be recorded on Forms 2 and 3, Appendix A

f) CP system components shall be visually inspected for proper installation,
labeled where appropriate, and protected from environmental and human
damage. Other testing shall be undertaken as required, to ensure
performance of the CP system.
6.1.3. Sacrificial Anode Cathodic Protection System.
Appendix A provides typical forms (Forms 6 to 9) for CP system circuit verification. These
forms are examples for testing and inspection data recording. These example forms can be
modified for specific requirements.

6.1.4. Prior to connection of galvanic anodes with the metallic structure, the following inspection and
testing shall be conducted as a minimum:

a) Potential of the anode circuits shall be tested and verified. Test results shall
be recorded on Form 6, Appendix A.
b) Discontinuity between positive and negative circuits and adjacent and
isolated anode circuits shall be tested and verified. Test results shall be
recorded on Form 9, Appendix A.
c) Potential of the permanent reference electrode shall be tested and verified.
Test results shall be recorded on Form 5, Appendix A.
d) Continuity of negative circuits shall be tested and verified. Test results shall
be recorded on Forms 7 and 8, Appendix A
e) CP system components shall be visually inspected for proper installation,
labeled where appropriate, and protected from environmental and human
damage. Other testing shall be undertaken as required, to ensure
performance of the CP system.
6.2. Pre-Energizing Measurements

6.2.1. Prior to energizing of the CP system, the following measurements shall be made and
recorded in accordance with section 4.3:

a) „As Found‟ metallic structure interface corrosion potentials shall be measured with respect to
permanently installed reference electrodes. The specialist shall measure the metallic structure
potentials both at low (about 10 MΩ to 20 MΩ) and high (about 500 MΩ to 1000 MΩ) input
impedance to determine whether the contact resistance of the electrodes or cells to the soil or
water is excessive.
b) „As Found‟ metallic structure interface corrosion potentials with respect to portable reference
electrodes at locations determined by the specialist
c) „As Found‟ metallic structure interface corrosion potentials with respect to the anode system.
d) Checking of the polarity of electrical circuits and confirming that the positive connections are to
the anode and the negative connections are to the structure.
e) Obtain monitoring coupon potentials, at all metallic structure test points

Note: These pre-energization tests may not be possible where temporary galvanic anodes are
connected during the course of construction. Therefore, the temporary CP system shall be
disconnected to carry out the above measurements.

6.3. Initial Energizing and Current Adjustment
Appendix B provides typical form (Forms 10, 11 & 12) for CP system initial energisation. Appendix C
provides typical form (Form 13 & 14) for CP system performance assessment and verification. These
forms are examples for testing and inspection data recording. These example forms can be modified for
specific requirements.

6.3.1. Following successful completion of all circuit verification tests as specified above in 6.1 & 6.2,
CP system shall be energized initially at low current (10 to 20 percent) capacity.
6.3.2. Within a few minutes after energizing, potential of the metallic structure shall be measured
with respect to the permanently installed reference electrodes and at all accessible location
using portable reference electrode to confirm that metallic structure potential has shifted in
negative direction from the values measured in accordance with 6.2.1.a and 6.2.1.b. If any
value shift in positive direction that shall be investigated by the specialist who shall determine
any requirements for additional testing or remedial works or both.
6.3.3. After confirming metallic structure potential polarization towards more negative potentials at
all monitoring locations, the specialist shall determine the value of current at each anode of
CP system that shall be set for its initial operational period.
6.3.4. Current shall be increased incrementally until the „current-on‟ metallic structure potentials
measured with respect to Permanente reference electrodes have shifted towards more
negative potentials by 200 to 300 mV. Current shall be increased gradually and in small
increments. Slow polarization at relatively low current density may be beneficial. Individual
anode current output adjustment procedures shall be followed for each metallic structure.
Test results shall be recorded on Form 11 & 12, Appendix B.
6.3.5. The specialist shall ensure that metallic structure potential is not exceeding the upper limit of
the protection criteria (as given above in 5.1) at any reference electrode location.
6.3.6. The specialist shall determine the period of initial polarization during which these initial
settings of current shall be maintained for polarization prior to initial performance
assessment. Typically it shall be between 3 days and 7 days after initial energisation
depending upon the actual rate of polarization. If a slow polarization energizing policy (low
initial current) is adopted, full polarization may require longer than 7 days. Test results shall
be recorded on Form 11 and 12, Appendix B.
6.3.7. The specialist shall measure and record the output voltage and current values of dc power
supplies providing current to the CP systems at regular intervals (as and when required)
during the initial polarization period. Test results shall be recorded on Form 10, Appendix B.

6.4. Initial Performance Assessment

Appendix C provides typical form (Form 13 & 14) for CP system performance assessment and
verification. These forms are examples for monitoring data recording and can be modified for specific
requirements.

6.4.1. Initial performance of the CP system shall be assessed after the initial polarization period has
elapsed. This assessment shall include the following measurements:

a) Voltage output and current supply to each metallic structure.

b) Using the Clamp-On ammeter and calibrated current shunt, measure the current flow of
each anode. Record outputs and compare to expected values to ensure they are within
design limits. In addition, measure and record the amount and direction of current flow
for:
i. Each grounding electrode (CPG) at isolating flanges.
ii. Monitoring coupons.
c) ON / Instant-OFF potentials at a representative number of locations on nearby CP
systems and structural items to ensure operation of the CP system does not adversely
effect other items.Typical locations for readings are pipe crossings, pipeline
terminations, sacrificial anode systems, at permanent RE locations, and adjacent plant
earthing grid. Structures having a potential shift in the less negative (more positive)
direction 20 mV or more may require remedial action to prevent stray current corrosion.

Note: Some structures require substantial periods of time to achieve full polarization. It
may be necessary to conduct a survey after initial energization to check the potential on
such structures.

d) Current ON and INSTANT OFF strcture-to-soil potentials for each strcture using test
leads at the monitoring test stations and bonding test posts.

e) Current ON and INSTANT OFF potentials for each moniotring coupon and each
permanent reference electrode.

f) The time interval between the current interruption and the measurement of „instant off‟

metallic structure potential shall be sufficient to avoid any transient voltage arising from
switching surges, capacitance or reactance effects, and sufficiently short to avoid
significant depolarization. Typical values are between 0.1 and 0.5 seconds but
appropriate values will vary from system to system and with the extent or period of
polarization. The measurement period (for digital „counting‟) should be sufficiently short
to avoid significant depolarization during the measurement period, but of sufficient
length not to degrade the accuracy or noise rejection capability of the measurement
system. Typical values are between 0.1 and 0.5 seconds, but calibration and other
instrumentation calculation steps may dictate a longer period than this between
subsequent measurements.
6.4.2. The specialist shall analyze the data collected in accordance with 6.4.1 above to assess
compliance with protection criteria specified in 5.1 above.

6.5. Adjustment of Current Output

6.5.1. Based upon the interpretation made in accordance with 6.4.2, the specialist shall determine
whether the output current should be increased, decreased or maintained. The specialist shall
determine whether the CP system shall be run at constant current or constant voltage output
supply mode or in some form of closed loop monitoring and automatic control mode.
6.5.2. Following initial adjustment, the specialist shall demonstrate compliance with protection criteria
specified in 5.1 above to SABIC.
6.5.3. A copy of „CP system performance data‟, in compliance with 6.4.1, shall be submitted to SABIC
before it leaves the site.
7. System Records and Documentation

7.1. Quality and Test Records
The quality assurance system plan, the quality documents arising where from, and the inspection and test
results shall form the permanent records of the installation of the system.

7.2. Installation & Commissioning Report
Installation and commissioning report for the CP system shall be prepared, which shall have the following as
a minimum:
a) A general description of the works
b) SABIC, design engineer, supervising engineer, contractor, subcontractor(s) and the specialist(s) and
their responsibilities
c) A copy of the materials specifications, installation procedures, and design calculations
d) A detailed description of the installation, completion date, and commissioning date
e) As-built drawings, detailing the installation and its components to a sufficient detail to facilitate future
requirements for inspection, maintenance, and reconstruction of the system and its major components.
They shall also indicate deviations or variations from the original design drawings.
f) A list of the major components of the CP system with data sheets and the source(s) of spare parts and
maintenance for these components and for the overall system
g) Test results of pre-commissioning checks and inspection
h) Results of the measurements and data taken before energizing of the system, while the system was
energized, and during the initial system performance
i) A record of the „as left‟ operating conditions of the system
j) A copy of the permanent records, in accordance with 7.1
k) Recommendations for any modifications to the CP system
l) Other documents required by SABIC

7.3. Operation and Maintenance Manual

Operation and maintenance manual shall be prepared for the CP system, which shall incorporate the
following as a minimum:
a) A detailed description of the system, describing what it does, how it works and when it was installed and
commissioned
b) A set of „as built‟ drawings and a list of components used in CP system along with names and
addresses of their manufacturers and suppliers
c) Details of the power source of the ICCP system only, its rating, fittings, protection system, earthling,
control and circuit and wiring diagram
d) Detailed (step by step) guide for system operation, that is, how and when to adjust, which controls
perform what function, operating limits, procedures for shutting down and re-energizing. For remote
monitoring systems see Note 1 & 2 below.
e) Detailed guide and procedures for system monitoring
f) Detailed recommended routine maintenance and inspection intervals and procedures in accordance
with 8.2 and 8.3.
g) Recommended procedures for future performance assessments and the interpretation of the data there
from
h) Perform or computer data for recommended routine maintenance, inspection and performance
assessment activities
i) Fault finding procedures for faults within the CP electrical power supply (ac and dc), short circuits and
open circuits in the CP system
j) Maintenance and repair procedures for the electrical power supply equipment, any data logging and
control equipment and the anode system, sealant or decorative coating
k) Other documents required by SABIC

Note 1:
In case of a “Remote Monitoring and Control System” the contractor shall provide a detailed step up
step guide for each (major & sub menu) screen window on system operation and adjustment. The
contractor shall also provide a comprehensive demonstration and training to SABIC CP Engineers
and/or Technicians on operation of both hardware and software. The training shall include both
theoretical and practical (hands on-operation) sessions.

Note 2:
For Sacrificial anode cathodic protection system some of the above requirements (remote monitoring
system and control) are not necessary since it does not exist.

7.4. Submittals and Completion Dates

a) Records of testing and commissioning shall be available, as specified in section 4.3, for review by
SABIC during all stages of execution of the works. In accordance with the quality assurance plan,
SABIC may certify or approve some of these records during the works.
b) Installation and commissioning report and the operation and maintenance manual shall be completed
and supplied to SABIC within 30 days after completion of the initial performance assessment or within a
period agreed between SABIC and the contractor.

c) The installation and commissioning of the CP system shall be considered complete only when accepted
by SABIC, after successful demonstration of the satisfactory performance of the system by the
contractor in accordance with 5.1 & 5.2.
d) Prior to issuing the completion certificate, SABIC will check and ensure compliance with 6.1 to 6.5 and
7.2 and 7.3.
e) SABIC will ensure performance of CP system as demonstrated by the contractor in compliance with 5.1
and 5.2.

8. Operation and maintenance
Appendix C provides a typical form for logging the system monitoring data and performance assessment. These
forms are included here as guideline for customizing the forms for different systems.

8.1. System Operation
8.1.1. After commissioning and initial performance assessment and acceptance by SABIC, the
system shall be operated by the contractor for a period of 12 months (The final acceptance of
the system by SABIC shall be after 12 months subject to satisfactory operation of the
system). The system operation shall include the following:

a) Function check of the following (typically every 1 month by SABIC or every 3 months by the
contractor).
i. Confirmation that all sub-systems are functioning
ii. Measurement of output voltage to each metallic structure of the cathodic protection
system.
iii. Measurement of output current to each anode of the cathodic protection system.
b) Performance monitoring of the following (typically every 3 months by the Contractor.
i. Measurement of “current-on” potentials.
ii. Measurement of “instantaneous off” polarized potentials.
iii. Measurement of parameters from any other sensors installed as part of the
performance monitoring system.
iv. A full close-up visual inspection of the cathodic protection system and structure.
v. Assessment of data by the Specialist.
vi. Adjustment of current output
8.1.2. All measurement/testing/inspections shall be in accordance with section 6 above.
8.2. System review report.

8.2.1. The report shall detail the following and shall be submitted to SABIC within 30 days after
completion of system review:

a) The work undertaken;
b) The data collected;
c) Recommendations for any changes to the operation and maintenance procedures;
d) Recommendations for any changes to the cathodic protection system.
e) Recommendations for frequency and scope of monitoring
8.3. Long Term Operation

8.3.1. The system shall continue to be monitored and maintained by SABIC in accordance with
8.1.1 and at time intervals given in 8.3.1e.
8.3.2. Each performance monitoring shall include and perform the measurements and adjustments
described in 8.1.1a and 8.1.1b.
8.3.3. The SABIC engineer who will conduct the routine monitoring shall review the previous data
and the recommendations made in the system review report for future monitoring and apply
them where necessary.
8.3.4. The SABIC engineer shall consider extending the intervals between routine inspection and
testing if no faults, damage or significant variation in system performance are indicated by
successive inspections/tests.

NOTE:
It is to be noted that long-term polarization arising from long term cathodic protection could result in a
reduction in the requirement for current.

Typical Form for CP System – Circuit Verification

Form 1
Continuity Checks Between System Positive Output and Anode Feeders

Structure: ______________________ Inspection Date & Time: __________________________
Contractor QA/QC Engr. Name & Signature: __ _______________________________________
CP Sub-Contractor, CP Tech./Engr. Name & Signature: ________________________________
CP Sub-Contractor, CP Specialist Name & Signature: _________________________________