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West African Gas Pipeline Regulations, 2005 (L.I. 1814).

6. CATHODIC PROTECTION AND CORROSION CONTROL Corrosion Control Records 6.1 The Operator shall maintain records and maps/alignment drawings to show the location of cathodically protected piping, cathodic protection facilities, pipe-to-soil test stations, galvanic anodes, rectifiers, ground beds, and neighbouring structures bonded to the cathodic protection system. Records or maps showing a stated number of anodes, installed in a stated manner or spacing, need not show specific distances to each buried anode. 6.2 Each record or map/alignment drawings required by Regulation 6.1 shall be retained for as long as the pipeline remains in service.

 6.3 The Operator shall maintain a record of each test, survey, or inspection required by this Regulation in sufficient detail to demonstrate the adequacy of the corrosion control measures or that a corrosive condition does not exist, and shall retain all such records for at least 5 years, except that records related to Intelligent Pig Surveys and repair of corroded pipelines shall be retained for as long as the pipeline remains in services.
 6.4 The Operator shall record cathodic protection readings in trend format and shall retain all such recordings for inspection for the lifetime of the Pipeline System.
 External Corrosion Control
 6.5 The design for the cathodic protection of the Pipeline System and its components shall be in accordance with the specification and procedures prescribed in NACE RP0169.
 6.6 Where the Pipeline System is buried or submerged it shall be protected against external corrosion, including the following:
 (a) it shall have an external protective coating meeting the requirements of Regulations 6.8; and 
 (b) it shall have a cathodic protection system designed to protect the Pipeline System in accordance with this Regulation and installed and placed in operation during pipeline construction.
 6.7 Whenever the Operator has knowledge that any buried portion of the Pipeline System is exposed, the exposed portion shall be examined for evidence of external corrosion if the pipe is bare or if the coating is deteriorated. If external corrosion is found that requires remedial action, the Operator shall investigate circumferentially and longitudinally beyond the exposed portion (by visual examination, indirect method, or both) to determine whether additional corrosion requiring remedial action exists in the vicinity of the exposed section.
 6.8 Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion control shall:
 (a) be applied on a properly prepared surface;
 (b) have sufficient adhesion to the metal surface to effectively resist underfilm migration of moisture;
 (c) be sufficiently ductile to resist cracking;
 (d) have sufficient strength to resist damage due to handling and soil stress; and 
 e) have properties compatible with any supplemental cathodic protection.
 6.9 Each external protective coating which is an electrically insulating type shall also have low moisture absorption and high electrical resistance.
 6.10 Each external protective coating shall be:
  (a) inspected prior to lowering the pipe into the ditch and backfilling, and any damage to the coating shall be repaired;
  (b) protected from damage resulting from adverse ditch conditions or damage from supporting blocks; and 
  (c) If practical, inspected at intervals not exceeding 5 years using close interval potential survey or direct current voltage gradient or comparable testing procedures.
 6.11 If coated pipe is installed by boring, driving, drilling or other similar method, precautions shall be taken to minimize damage to the coating during installation, and any damage detected shall be protected using appropriate cathodic protection.
 6.12 Each cathodic protection system reacquired by this Regulation shall provide a level of cathodic protection that complies with NACE RP0169. NACE RP0190 shall be followed for the protection of joints, valves, and fittings on metallic underground or submerged pipelines and piping systems.
 6.13 If amphoteric metals (metals of different anodic potential than the remainder of the pipeline) are included in a buried or submerged pipeline:
 (a) the amphoteric metals shall be electrically isolated from the remainder of the pipeline and cathodically protected; or :
 (b) the entire buried or submerged pipeline shall be cathodically protected at a cathodic potential that meets the requirements of NACE RP0169.
 6.14 The amount of cathodic protection shall be controlled so as not to damage the protective coating or the pipe.
 6.15 Each buried or submerged pipeline shall be electrically isolated from other underground metallic structures, unless the pipeline and the other structures are electrically interconnected and cathodically protected as a single unit.
 6.16 Insulating devices shall be installed where electrical isolation of a portion of a pipeline is necessary to facilitate the application of corrosion control.
 6.17 Cased crossings shall not be used.
 6.18 An insulating device may not be installed in an area where a combustible atmosphere is anticipated unless precautions are taken to prevent arcing.
 6.19 Where a pipeline is located in close proximity to electrical transmission tower footings, ground cables or counterpoise, or in other areas where fault currents or unusual risk of lightning may be anticipated, it shall be provided with protection against damage due to fault currents or lightning, and protective measures shall also be taken at insulating devices.
 6.20 Each onshore pipeline under cathodic protection required by this Regulation shall have sufficient test stations or other contact points for electrical measurement to determine the adequacy of the cathodic protection:
 (a) each test lead wire shall be connected to the pipeline so as to remain mechanically secure and electrically conductive; 
 (b) each test lead wire shall be attached to the pipeline so as to minimize stress concentration on the pipe;
 (c) each bared test lead wire and bared metallic area at point of connection to the pipeline shall be coated with an electrical insulating material compatible with the pipe coating and the insulation on the wire; and 
 (d) each test point shall be identified with a marker post.
 6.21 The Operator shall maintain a continuing program to minimize the detrimental effects of stray currents.
 6.22 Each impressed current type cathodic protection system or galvanic anode system shall be designed and installed so as to minimize any adverse effects on existing adjacent underground metallic structures. Sacrificial galvanic anodes shall be designed to provide a minimum design life greater than the design life of the Pipeline System.
 6.23 Anodes shall be designed to provide a minimum maintenance life for the offshore portion of the Pipeline System of 40 years. 
 Internal Corrosion Control 
 6.24 Corrosive gas may not be transported in the Pipeline System.
 6.25 Whenever any pipe is removed from the Pipeline System for any reason, the internal surface shall be inspected for evidence of corrosion. If internal corrosion is found:
 (a) the adjacent pipe shall be investigated to determine the extent of internal corrosion; and 
 (b) steps shall be taken to minimize the internal corrosion.
 6.26 Corrosion coupons or other suitable means shall be used to determine the effectiveness of the steps taken to minimize internal corrosion. Each coupon or other means of monitoring internal corrosion shall be checked two times each calendar year, but with intervals not exceeding 7 months.
 Atmospheric Corrosion Control
 6.27 The Operator shall, at intervals not exceeding 1 year, inspect each pipeline segment that is exposed to the atmosphere and take remedial action whenever necessary to maintain protection against atmospheric corrosion.
 6.28 Each aboveground part of the Pipeline System that is exposed to the atmosphere shall be either painted, coated or jacketed with a material suitable for the prevention of atmospheric corrosion except where the Operator can demonstrate by test, investigation, or experience in the area of application that a corrosive atmosphere does not exist.
 6.29 Each aboveground part of the Pipeline System shall be visually inspected at least annually and if atmospheric corrosion is found, cleaned and either painted, coated or jacketed the areas of atmospheric corrosion on the pipeline with a material suitable for the prevention of atmospheric corrosion.
 Repair of Corroded Pipe
 6.30 Each segment of pipeline with general corrosion and with a remaining wall thickness less than that required for the Maximum Allowable Operating Pressure of the pipeline shall be replaced or the operating pressure reduced commensurate with the strength of the pipe based on actual remaining wall thickness. However, corroded pipe may be repaired by a method that reliable engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting so closely grouped as to affect the overall strength of the pipe is considered general corrosion for the purpose of this Regulation.
 6.31 Each segment of a pipeline with localized corrosion pitting to a degree where leakage might result shall be replaced or repaired, or the operating pressure shall be reduced commensurate with the strength of the pipe, based on the actual remaining wall thickness in the pits.
 6.32 Under Regulations 6.30 and 6.31, the strength of pipe based on actual remaining wall thickness may be determined by the procedure in ASME B31G.
 Pipeline Integrity Management Plan
 6.33 The Operator shall prepare and submit to the Authority a Pipeline Integrity Management Plan which is consistent with internationally recognised industry standards and good practice applicable to high pressure Natural Gas pipelines.
 6.34 The Pipeline Integrity Management Plan shall periodically be reviewed and updated in accordance with internationally recognised industry standards and good practice applicable to high pressure Natural Gas pipelines, and a copy of the revised Pipeline Integrity Management Plan shall be provided to the Authority on each occasion that it is updated.
 Intelligent Pig Survey
 6.35 An Intelligent Pig Survey shall be performed on the main line piping for monitoring internal and external corrosion within five years after the pipeline is first placed in operation. Lateral lines will not be pigged unless corrosion control records indicate a need for an Intelligent Pig Survey. Future Intelligent Pig Surveys of the main line will be performed as deemed necessary based on the Pipeline Integrity Management Plan.

Subject : West African Gas Pipeline  

Procedure to Follow


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Responsible Institution


West African Gas Pipeline Company Limited (WAPCo)

Codemm House, Nii Nortei Nyanchi Street, West Airport

Relevant Forms to Download

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Online System

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Fees/ charges

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