Repair of Steel Pipelines

8/12/2019 Repair of Steel Pipelines

1/17

-1-

S - 26

STANDARD CONSTRUCTION SPECIFICATIONS

SECTION 26

REPAIR OF STEEL PIPELINES

This Specification covers the repair of steel pipelines as used in Company onshore oil and gas

operations.

In this Section, reference is also made to Standard Construction Specification Sections S-1, S-

2, S-3, S-4, S-10, S-20, S-2 1, S-23, S-24, S-25, S-29, S-34 and S-35.

The Shell Petroleum Development Company of Nigeria Limited

(Second Edition - 1982)

(Revision 3 - January 1985)

SECTION 26 REPAIR OF STEEL PIPELINES


2/17

-2-

I N D E X

Page

26.1 SCOPE AND RESPONSIBILITIES 4

26.2 DETAILED PROGRAMME AND WORK PROCEDURE 4

26.3 SAFETY AND ACCESS TO SITE 5

26.4 MATERIALS 5

26.4.1 Supply and Responsibilities 5

26.4.2 Materials Supplied by The Contractor 5

26.4.3 Checking Correctness of Materials 6

26.4.4 Handling and Haulage 6

26.4.5 Storage of Materials 6

26.5 EQUIPMENT 6

26.5.1 supply 6

26.5.2 Suitability for Duty 6

26.5.3 Temporary Power Supplies 6

26.5.4 Temporary Lighting 7

26.6 PRELIMINARY CHECKS AND NOTIFICATION OF START DATE 7

26.6.1 Preliminary Checks 7

26.6.2 Notification of Start Date 7

26.7 SITE PREPARATION 7

26.7.1 Area Clearance ` 7

26.7.2 Excavations 8

26.8 CONSTRUCTION OF REPLACEMENT PIPELINE SECTION 8

26.8.1 Stringing New Pipes 826.8.2 Bends and Field Bending 9

26.8.3 Ensuring Cleanliness of Pipes and Fittings 9

26.8.4 Jointing and Welding 9

26.8.5 Inspection and Radiography 9

26.8.6 Pressure Testing 9

26.8.7 Replacements or Making Good Faulty/Damaged Item 9

26.8.8 Coating and Wrapping 10

26.8.9 Lowering-in 10

26.9 PROCEDURE FOR PIPELINE REPAIRS 10

26.9.1 General 10

26.9.2 Collection and Disposal of Line Fill and Spillage 11


3/17

-3-

26.9.3 Cathodic Protection Circuits 11

26.9.4 Pipeline Inspection at Repair Locations 11

26.9.5 Hot Tapping and Stopple-Plugging 12

26.9.6 Pipe Cutting and Bevelling 12

26.9.7 Use of Encircling Clamps for Stopping Leaks 12

26.9.8 Connecting-in New Pipeline Sections

1226.9.9 Pressure Testing 13

26.10 REMOVAL AND SALVAGE OF WELDED OR SCREWED LINE 13

26.10.1 General 13

26.10.2 Site Preparation and Excavations 13

26.10.3 Draining, Flushing and De-gassing the Line 14

26.10.4 Lifting Buried Lines 14

26.10.5 Cutting up the Line and End Preparation of Pipe Lengths 14

26.10.6 Transportation and Storage of Salvaged Materials 14

26.11 BACKFILL AND REINSTATEMENT

26.12 REPAIR OF PIPELINES IN MARSH AND SWAMP AREAS 15

26.12.1 General 15

26.12.2 Boats, Barges and Equipment 15

26.12.3 Preliminaries and Company Representatives 16

26.12.4 Cleaning the Line 16

26.12.5 Repair Procedure 16


4/17

-4-

SECTION 26 REPAIR OF STEEL PIPELINES.

26.1 SCOPE AND RESPONSIBILITIES

This Specification covers the basic requirements and procedures to be used for the repair of

steel pipelines in all areas of the Company onshore oil and gas operations.

The Specification is written in general terms in as much as it applies to buried lines, above

ground lines, liquid carrying lines and gas carrying lines. Where special requirements arise for

any of the above applications these will be noted as such in the text.

The general obligations and responsibilities placed on the Contractor in executing the Contract

Works are covered by Standard Construction Specification S-1 (General; Requirements).

Specialised aspects of the pipeline repair operation (e.g. pipe fabrication, coating and

wrapping, welding, inspection and radiography, hot-tapping, pressure testing, etc.) are dealt

with in other sections of the Company's Standard Construction Specifications and reference

should be made to these wherever applicable.

All work must be carried out in accordance with the Contract Documents, Drawings and

Specifications 'and any other Company or National standards listed therein.

The Contractor shall maintain in his possessions at the Work Site, current issues of all

specifications and standards as listed in the Contract Documents, Drawings and Specifications,

and as referred to herein.

All documentation, certification, radiographs and test data etc. shall be formally handed over to

the Company Representative as and when they become available before completion of the

Contract Works.

26.2 DETAILED PROGRAMME AND WORK PROCEDURE

The Contractor shall submit to the Company for vetting and approval, a detailed work

procedure, programme and timetable for execution of the Works. This shall include (as

applicable):-

Procurement of all necessary materials

Organisation of sub-contracts

Erection of temporary fencing around working areas

Excavation to expose the pipelines

Stripping of pipe coating and ultrasonic surveys

Drain down, gas freeing and cutting of lineQualification of weld procedures and welder testing

Welding on split tees and branch connections

Prefabrication and testing of tie-in piping


5/17

-5-

Tie-in welding

Radiography and testing

Pipeline repair operations will be stringently controlled by the Company. The Contractor shall

prepare detailed work procedures and submit them in writing to the Company for

approval/amendment in sufficient time (as directed) before the work is due to start.

26.3 SAFETY AND ACCESS TO SITE

Throughout the duration of the Contract, 'the Contractor shall conform strictly to the

requirements of Standard Construction Specification S-35 (Contractor Safety) and shall be

responsible for ensuring that all Contractor's (and sub-contractor's) personnel maintain proper

safety precautions and work according to the requirements of this document and any other

supplementary requirements stipulated by the Company. The Contractor must carefully

establish with the Company Representative which areas of the work require safety

permits to work and the applicable Hazardous Area Classifications. He must then

ensure that the necessary Permits are obtained before starting work according to the formalprocedures laid down by the Company and that these are kept valid for the duration of the

Works. Fire fighting equipment shall be held at the ready during the pipeline repair operations

and such other precautions implemented as specified by the Company Representative.

Relaxation of the requirements for fire fighting equipment will only occur when the line

contents are non-imflammable (e.g. water, brine, etc.), and the work is being carried out in a

non-hazardous area.

Prior to entry upon the Site the Contractor shall ensure that all requirements for entry have

been complied with and that all necessary fire-fighting and safety equipment is to hand.

The contractor shall provide all necessary access facilities and assistance to responsible

Company Representative(s) for inspecting and checking all aspects and parts of the repair

works.

Bell holes and other excavations made in order to repair underground lines shall provide ample

working space for welders and all other men involved in the repair Works and allow them to

make a quick exit in the event of' an emergency or any danger arising. Sides of excavations

shall be properly shored. and braced so as to prevent any possibility of earth slips or cave-ins.

26.4 MATERIALS

26.4.1 Supply and Responsibilities

Materials will generally be supplied by the Company unless otherwise specified in the

Contract. The Contractor shall be responsible for the collection of all Company-supplied

materials from Company Stores and their subsequent transportation to Site. The offloading,

sorting and safe storage of all materials and equipment at Site shall be the responsibility of the

Contractor.

26.4.2 Materials Supplied by the Contractor

Where specified in the Contract Documents, or where the Company has directed or agreed that

the Contractor shall supply some of the materials to be used in the repair Works all materials


6/17

-6-

thus supplied by the Contractor shall strictly conform to the relevant Standards and

Specifications as directed by the Company. The cost of all such materials shall he included in

the Contract Price.

26.4.3 Checking Correctness of Materials

The Contractor shall be responsible for checking that all materials (whether they be Companysupplied or Contractor supplied) are present and correct in accordance with the Drawings and

Specifications. The Company Representative must be advised immediately of any material

defects or shortages. No damaged or corroded materials shall be used in the repair Works.

26.4.4 Handling & Haulage

The Contractor shall be responsible for the handling of all materials, supplies, machinery and

equipment used in the repair Works and their haulage to and from the Work Site(s). Handling

and haulage shall be carried out in accordance with Clauses 25.2.7 and 25.2.8 of Standard

Construction Specification S-25 (Pipeline Construction).

26.4.5 Storage of Materials

The Contractor shall be responsible for the proper storage, protection and security of all

materials and equipment as stipulated in Standard Construction Specification S-1 (General

Requirements) and will be liable for the replacement costs of any materials or equipment lost

or damaged.

All materials and equipment received shall be stored well clear of the ground on timber skids

or pallets and shall be properly protected from the weather. All machined items such as bolt

threads or the contact faces of flanges, shall be greased (if not otherwise protected) to preventcorrosion.

26.5 EQUIPMENT

26.5.1 Supply

Unless otherwise stated in the Contract Documents, the Contractor will be required to provide

all tools and equipment necessary for the correct execution of the repair Works. Where the use

of special tools and/or equipment supplied on loan by the Company is agreed, the Contractor

shall give a full week's notice to the Company Representative of the days on which thetools/equipment are actually required.

26.5.2 Suitability for Duty

The Contractor shall verify that all tools and equipment to be used for the repair Works are of

the correct type and are in good working order. Special attention shall be given to the specified

working ranges, limitations and condition of equipment, particularly where the pipeline repair

is to take place in hazardous locations or where the pipe diameter, wall thickness and pressure

or temperature conditions approach the maximum rating and working limitations of the

equipment.

All of the Contractor's tools and equipment shall be suitable for the work in hand and in good

working order and any items which are deemed (by the Company Representative) to be


7/17

-7-

unsuitable, worn or unserviceable, shall be replaced by the Contractor at his own expense. All

lifting equipment must be covered by a valid inspection/test certificate in accordance with Part

4 of Specification S-35 (Contractor Safety).

26.5.3 Temporary Power Supplies

The Contractor shall be responsible for the provision of all temporary power supplies requiredfor the execution of the repair Works. This shall be taken to include (as required) diesel-driven

generators, compressors and hydraulic pumps, plus all necessary fuel supplies and lubricants.

The Contractor shall ensure that all diesel engines intended for use in Zone 2 hazardous areas

are properly fitted with approved spark arrestors on their exhausts. The Safety Regulations

listed in Part 2 of Specification S-35 shall apply.

The positioning of all Zone 2 unsafe equipment and the location of fuel stores shall he well

outside any potentially hazardous area (taking into account the prevailing wind) and will be

subject to the approval of the Company Representative. The safe operation, security and

storage of all such equipment and fuel supplies, however, shall be the responsibility of theContractor.

26.5.4 Temporary Lighting

The Contractor shall supply all necessary temporary lighting and shall ensure that flame proof

enclosure are provided for temporary lighting systems in hazardous areas and that all

associated power generating equipment is located in a non-hazardous area.

26.6 PRELIMINARY CHECKS AND NOTIFICATION OF START DATE

26.6.1 Preliminary Checks

The Contractor shall first verify that all planned repair work operations are entirely possible

with respect to location, accessibility, size, pressure and temperature ratings, material

suitability or any other relevant factors and shall take account of all such matters in his detailed

work procedure.

26.6.2 Notification of Start Date

After the proposed work programme and detailed working procedures have been vetted and

approved by the Company, the Contractor shall give at least one week's notice reconfirming the

actual date on which he intends to start work.

26.7 SITE PREPARATION

26.7.1 Area Clearance

All preliminary work necessary on the pipeline right-of-way, access roads and storage areas

shall be carried out in accordance with the relevant parts of the following StandardConstruction Specifications:-

S-2 (Right of Way and Access Roads)


8/17

-8-

S-3, (Clearing, Grading and Surface Stripping)

S-4 (Earthwork at Construction Sites)

26.7.2 Excavations

In the case of underground pipelines, the contractor shall perform all excavations necessary for

access to the pipe(s) to be repaired. The width and depth of the trench excavation for any pipeshall be sufficient to properly conduct the work but in any case shall be at least 50 cms wider

than the outside diameter of the existing pipeline. Extra excavations and bellholes shall be

carried out as necessary so as to provide ample working space for cutting and jointing or the

installation of any valve or fitting.

The Contractor shall install all necessary timbering for shoring the sides of the excavations in a

safe manner so as to prevent earth slips and falls and shall also ensure that all excavations are

kept free of water.

The topsoil shall be segregated from the main fill or subsoil during excavation work and shall

be subsequently replaced last after the backfill operation.

Blasting with dynamite or any other explosive will not be permitted and the Contractor shall

conduct all excavation work in such a manner as to protect all persons and property (including

the pipeline and adjacent underground services) from injury and damage.

Mechanical excavators may only be used (with the prior approval of the Company

Representative) when the exact locations of the pipeline and all adjacent pipelines and other

underground services have been clearly established. Mechanical excavation shall not be

permitted within 1 metre (above or to either side) of any pipeline; water conduit or sewer;

power or telecommunications cable or any other service. In all such proximities, only handexcavation will he permitted.

All additional hand excavation, whether incurred by these restrictions or otherwise, shall be

done at no additional cost to the Company.

All excavated material shall be deposited in neat tidy rows or heaps, well away from the edges

of excavations and shall be placed in such a manner that it does not impede the escape of

personnel from the working area in the event of danger or an emergency. The contractor shall

remove the excavated material from the work site (and return it as required for backfill) if the

Company Representative considers it necessary for safety reasons or for improving the

efficiency of the work in hand.

26.8 CONSTRUCTION OF REPLACEMENT PIPELINE SECTION

26.8.1 Stringing New Pipes

Pipe haulage, offloading and Stringing -operations shall be organised so as to cause the least

practicable interference with-the use of the land, and gaps should be left in strings at intervals,

as directed, so as to allow the passage of livestock, vehicles and equipment across the route of

the pipeline.

The Contractor shall offload and string the pipes in an orderly line along one side of the right-

of-way as directed by the Company Representative using suitable approved plant. (Each pipe


9/17

-9-

length shall be set down in a slightly skewed position so as to make both ends easily accessible

for visual inspection).

Pipes shall not be placed directly on the ground and wrapped pipes shall be set down on well

padded timbers provided by the Contractor. Valves and fittings shall also be kept well clear ,of

the ground surface by timber skids.

26.8.2 Bends and Field Bending

The use of bends and field bending shall be strictly in accordance with Part 3 of Standard

Specification S-25.

26.8.3 Ensuring Cleanliness of Pipes and Fittings

The Contractor shall ensure that the inside of each pipe and fitting is thoroughly clean

immediately before jointing together. The inside of each pi pe shall be cleaned out by a pull-

through swab and all debris and foreign matter removed. Pipe manufacturer's serial numbering

labels shall be removed from inside pipes after the Contractor has recorded the labelledinformation on his pipe materials/welding charts.

Protective end caps on pipes, valves and fittings shall be retained/replaced in position as long

as practicable before jointing operations but shall not be relied upon as proof of internal

cleanliness immediately before jointing.

The pipeline itself shall be carefully kept clean internally and free of any tools and materials at

all times. When work is not actively in progress the ends of pipeline sections shall be closed

with approved caps securely fixed so as to resist unauthorised removal. The temporary

placement of welding rods or welder's gloves, vizors, chipping hammers, etc within the openend of the pipeline is expressly forbidden.

26.8.4 Jointing and Welding

The jointing and welding of pipes shall be carried out strictly in accordance with Standard

Specifications S-25 (Pipeline Construction) and S-21 (Welding).

Proposed welding procedures for all welding operations shall be submitted and qualified by the

Contractor. Only qualified welders shall be used. Welding procedure and welder qualification

tests shall be strictly in accordance with Standard Specification S-21.

The Contractor shall use mechanical line-up clamps for the alignment of welded joints and

wherever possible these shall be of the internal type.

Special welding procedures and qualification tests for branch fittings (split-tees, flanges and

weldolets etc.) shall be in accordance with the relevant parts of Standard Construction

Specification S-34 (Hot Tapping of Steel Pipelines).

26.8.5 Inspection and Radiography

The welding shall be inspected in accordance with the relevant parts of Standard ConstructionSpecifications S-21; S-34 and S-ZO (Radiographic Inspection and NDT) as applicable.

26.8.6 Pressure Testing


10/17

-10-

All pressure testing operations (including pre-cleaning, pigging, pre-installation tests on sub-

assemblies and final integrity tests) shall be carried out in accordance with Standard

Construction Specification S-29 (Pressure Testing).

The Contractor shall submit a detailed test programme and schedule of operations to the

Company for approval/amendment in sufficient time (as directed) before the work is due tostart.

The Contractor shall determine the locations of any leakages or any faulty or suspect pipe

material, valves and fittings during pressure testing.

26.8.7 Replacement or Making Good Faulty/Damaged Items

Where faulty or suspect materials have been supplied for the repair Works by the Company,

their replacement and/or making good shall be carried out by the Contractor as Extra Work,

providing always that written agreement has been given by the Company Representative.

But in cases where the faulty or suspect materials were supplied by the Contractor (or where

leakage or damage has been caused by the Contractor overstressing the materials or testing to a

pressure greater than the specified test pressure) or if failure is due to faulty work performed by

the Contractor, the materials or component thus affected shall be repaired or replaced to the

satisfaction of the Company at the Contractor's own expense.

In any case, the whole of the Works shall be made good to the satisfaction of the Company

Representative.

26.8.8 Coating and Wrapping

The Contractor shall coat and wrap all buried lines in accordance with Standard Construction

specifications S-10 (Field Coating and Wrapping) and S-23 (Coating, Wrapping and

Concreting of Line Pipe). The Contractor shall repair any damaged or defective areas (or

suspect areas) in the pipe coating/wrapping in accordance with Specifications S-10 and S-23,

carrying out full holiday detection test procedures as specified. All materials used for pipeline

coating and wrapping repairs shall be entirely compatible with the existing coating and

wrapping materials.

All coating and wrapping operations shall be subject to the approval of the Company

Representative or Inspector who may, from time to time, cut out samples from the appliedcoat/wrap to check the thickness and composition of the material and carry out tests to

determine the adhesion of the coating to the pipe. The cost of repairing and making good small

localised areas of the coat/wrap damaged in the execution of such tests and checks shall all be

borne by the Contractor, irrespective of whether the tests prove the coating and wrapping to be

satisfactory or unsatisfactory.

26.8.9 Lowering-In

The repaired or renewed sections of pipeline shall be handled and lowered into the trench in

strict accordance with Part 5 of Standard Specification S-25 (Pipeline Construction).


11/17

-11-

Prior to lowering in any section of pipeline or fittings, the Contractor shall ensure the removal

of all stones, rocks and hard objects from the bottom of the trench excavation, which shall then

be prepared in accordance with Part 5 of Standard Specification S-25.

The prepared trench or pipe ditch must be inspected and approved by the Company

Representative before any repaired pipeline/fitting is lowered in.

26.9 PROCEDURE FOR PIPELINE REPAIRS

26.9.1 General

All procedures for pipeline repair shall be submitted for approval to the Company as detailed in

Clause 26.2 herein.

Prior to starting any repair operations on a pipeline in service, the necessary safety procedures

shall be carefully established and official Permits-to-Work obtained from the Company

Representative as detailed in Clause 26.3 herein. On no account shall any work commence

until the Contractor has given formal acknowledgment of receipt of the official Permits-to-Work and his understanding and acceptance of the various conditions and procedures laid

down therein.

26.9.2 Collection and Disposal of Line Fill and Spillage

The Contractor shall provide approved means for the safe collection and disposal of the line fill

in the repair area(s) and also any spillage which occurs during the repair operations. The

Contractor shall furnish all necessary pumps, temporary piping, hoses and connections and

(unless otherwise directed or agreed by the Company) shall also provide tanker trucks, or

barges, to empty the pipeline repair sections and transport the liquid contents to therecovery/disposal point as specified by the Company.

26.9.3 Cathodic Protection Circuits

Where a pipeline has cathodic protection by an impressed current system, the source(s) of

power will normally be switched off by the Company's Operations Department before issuance

of the Permits-to-Work to the Contractor for the pipeline repair Works.

Where, however, the Company requires the C.P. system to remain in operation during pipeline

repair work, the source(s) of power will not be switched off and the Contractor shall maintain

electrical continuity by connecting bypass jumper cables so as to bridge the points at which thepipeline is to be cut or disconnected or a fitting removed. Each electrical bypass cable

connection shall be made before the pipeline is cut or disconnected. The cables used for this

purpose shall be heavy section insulated flexible cables of approved type, such as used for

electric welding equipment. The connections shall be made by proper cable lugs and setbolts

or studs (not less than 12mm dia.) either clamped or welded (via steel pads) to the pipeline, or

connected as alternatively directed by the Company Representative.

These temporary bypass cables shall not be disconnected until the repair works on the pipeline

have been completed and the original C.P. circuit reinstated.

26.9.4 Pipe Inspection at Repair Locations


12/17

-12-

The pipe wrapping at each repair location shall be carefully removed and the surface of the

pipe in the vicinity of intended welding operations thoroughly cleaned of all coating, paint, rust

and dirt deposits by wi re brushing to bright metal.

Prior to any hot tapping operations, the pipe shall be prepared and inspected in accordance with

the Standard Construction Specification S-34, with checks for corrosion damage and

laminations being applied to the standards detailed therein. Hot tapping shall proceed onlyafter the Company Representative has inspected and approved the examination and test results.

If the area thus inspected and tested is found to be unsuitable, the Contractor shall strip and

prepare other locations as directed by the Company Representative.

Pipeline repair work shall proceed only after the Company Representative has inspected the

section which is to be, repaired or replaced and has given formal instructions for the repair

works to proceed.

26.9.5 Hot Tapping and Stopple Plugging

Where it is essential that a pipeline remain in service during repair, replacement or re-routingof sections and hot tapping operations are required, the Contractor shall carry out all hot

tapping work strictly in accordance with Standard Construction Specification S-34 (Hot

Tapping of Steel Pipelines).

Similarly, if it is necessary to plug a section of line, the Contractor shall conduct all Stoppling

operations in accordance with Standard Specification S-34.

26.9.6 Pipe Cutting and Bevelling

All pipe cutting shall be carried out by approved forms of specialised pipe cutting equipment.

The equipment may be either of mechanical cold-cutting type or (when conditions allow usage)

a thermal cutting and bevelling machine. Thermal cutting will not be permitted for cutting any

oil or gas pipeline or in any situation where there is a possibility of a fire hazard. Manual

thermal cutting or bevelling (using a hand-held cutting torch) will not be permitted under any

circumstances in the preparation of pipe ends for welding.

Cuts shall be made in true circles, square to -the axis of the pipe. Welding bevels shall be

made smooth and uniform, without indentations, in accordance with Part 5 of Standard

Specification S-21 and the qualified welding procedure.

The cut and bevelled ends of pipes shall be checked to ensure freedom from laminations.

26.9.7 Use of Encircling Clamps for Stopping Leak

Where approval has been given by the Company, the Contractor shall use an encircling clamp

with pinhole locating probe and plugging screw (as manufactured by approved specialist

proprietary companies) for sealing a small localised leakage perforation. The Contractor shall

strip off the pipe coating adjacent to the leak, if possible, then fit the clamp and seal the leak.

A check on the pipe wall thickness in the vicinity of the clamp shall be made before seal

welding the clamp.

26.9.8 Connecting-in New Pipeline Sections


13/17

-13-

(a) Tie-in Welds

Before any welding, cutting or grinding operation is performed on the existing pipeline, the

Contractor shall first ensure that the line is free of residual gas by systematic checks with

Company-approved experimenters. All such tests are to be done in the presence of the

Company Representative and the meter readings properly witnessed and recorded.

All welding procedures shall have been previously submitted to the Company by the

Contractor for approval and qualification in accordance with Standard Construction

Specification S-21 (Welding). Only fully experienced qualified welders shall be used and all

welding shall be strictly in accordance with Specification S-21. The Contractor shall , use only

conventional welding methods for tie-in welds and welding operations shall be strictly

controlled to ensure high quality welds. Proper line up clamps shall be used, for piping

alignment.

(b) Inspection

All tie-in welds shall be subjected to 100% radiographic inspection. This shall be carried out

in accordance with Standard Specifications S-21 and S-20 (Radiographic Inspection and NDT).

Radiographs shall be S" Subject to the approval of the Company Representative and no attempt

at weld repair or the elimination of defects shall be undertaken without his discretionary

agreement.

26.9.9 Pressure Testing

Purging, filling, pigging and flushing operations and pressure testing of the pipeline afterrepairs have been completed shall be carried out where called for in the Contract Works and as

directed by the Company Representative. Filling and pressure testing shall be carried out in

accordance with Standard Construction Specification S-29 (Pressure Testing). The required

test pressure will be advised by the Company and on no account shall the test pressure

specified for the particular section of pipeline be exceeded.

REMOVAL AND SALVAGE OF WELDED OR SCREWED LINE

26.10.1 General

The Contractor shall identify the pipeline section(s) to be taken up and removed, usingdrawings and instructions provided by the Company Representative and (in the case of buried

lines) by using Pipeline metal detectors. and digging trial holes to definitely establish the

identity and Position of the line.

Before starting any work (including the digging of trial holes), the necessary safety procedures

must be carefully established with the Company Representative and official Permits-to- Work

issued by the Company. The Contractor shall also give formal acknowledgment of receipt of

each Permit, signifying his understanding and acceptance of the various conditions and

procedures laid down therein, before starting the work covered by the Permit.

26.10.2 Site Preparation and Excavations


14/17

-14-

The Contractor shall clear the pipeline right-of-way and carry out all necessary excavation

work in accordance with Clause 26.7 herein.

Note: The limitations on the usage and working proximity of mechanical excavators to the

line being removed (as stipulated in 26.7.2) may be varied by the prior direction or agreement

of the Company.

26.10.3 Draining, Flushing and Degassing the Line

The Contractor shall drain, flush out and degass the section(s) of pipeline to be removed in

accordance with the Company's instructions. The Contractor shall provide approved means for

the safe collection and disposal of the line fill and any spillage which may occur during

drainage and flushing operations.

The Contractor shall furnish all necessary pumps, swabbing pigs, temporary piping and valves,

hoses and connections required for pigging, flushing and degassing the line section(s) and

(unless otherwise directed or agreed by the Company) shall also provide tanker trucks, or

barges, for collecting the petroleum liquids (or petroleum/water mixtures) and transportingthem to the recovery/disposal point as specified by the Company. In any case, the Contractor

shall provide any tanker trucks or barges which may be required to bring up a supply of fresh

water for use in pigging and flushing operations.

26.10.4 Lifting Buried Lines

After removal of the ditch backfill sufficiently to expose the pipe, the Contractor shall carefully

raise the line from the ditch in such a manner as to prevent bending or overstressing the pipe or

damaging its protective coat and wrapping. Particular care shall be taken so as not to

overstress valves, fittings and connections. The contractor shall be responsible for any damageto pipes, pipe coating, valves and fittings that is attributable to poor or care-less handling

during the salvage operation.

26.10.5 Cutting up the Line and End Preparation of Pipe Lenghts

Flame cutters may only be used (In a Non-Hazardous Area) provided that all petroleum

residues have been thoroughly removed from the line by swabbing and flushing, and the

contents of the line have been checked in the presence of the Company Representative to verify

freedom from gas or flammable vapours. Otherwise, mechanical pipe cutters shall be used.

Screw thread jointed pipelines shall be cut through the middle of the couplings and the cuthalves of the coupling sleeves left in-situ on the pipe ends as thread protectors.

Welded pipe which is to be salvaged shall be cut into 10-12 metre lengths and the ends

bevelled so that the pipe is ready for rewelding when required for further use by the Company.

Cutting and bevelling shall be in accordance with Clause 26.9.6 herein and existing butt welds

shall be cut out preferentially. The bevelled ends shall be left as flame cut, without grinding,

but shall be smooth and uniform, without indentations.

26.10.6 Transportation and Storage of Salvaged Materials

The Contractor shall load all pipe, fittings and other salvaged materials and transport to a

storage location as specified by the Company. There he shall unload all salvaged material and

store as directed by the Company Representative.


15/17

-15-

The Contractor shall take all possible care during handling and transportation to avoid

damaging the pipe and other salvaged materials. Particular care shall be taken in the case of

coated and wrapped pipes to avoid damaging the coating and wrapping. Only broad band

slings or properly shaped end-hooks shall be used for lifting these pipes and the bolsters of the

transporter trucks shall be well padded with soft material.

The pipes shall be neatly stacked to a limited height as directed by the Company

Representative, during transportation and at the storage yard. During transportation, the pipes

shall be adequately secured in such a manner as to prevent damage to the coating and

wrapping.

BACKFILL AND REINSTATEMENT

Prior to any backfilling on the repaired/replaced section(s) of any pipeline, all inspections and

tests as called for by this specification and other specifications referred to herein, shall have

been completed and accepted as satisfactory by the Company Representative.

Backfill and reinstatement shall be carried out in accordance with Standard Specification S-25

(Pipeline Construction). In particular, the attention of the Contractor is drawn to the whole of

Part 6 and Clauses 25.7.9 and 25.8.7 therein.

26.12 REPAIR OF PIPELINES IN MARSH AND SWAMP AREAS

26.12.1 General

In marsh and swamp locations, different established working procedures, requiring specialisedequipment, will be used for pipeline repairs but the contractual responsibilities and formal

procedures as stipulated in Sections 26.1 to 26.6 herein shall still apply. The works shall also

be carried out in accordance with Part 8 of- Standard Specification S-25 (Pipeline Construction

Marsh and Swamp Areas).

26.12.2 Boats, Barges and Equipment

The Contractor shall supply all tools and equipment necessary for -properly carrying out repair

works to pipelines and flowlines in marsh and swamp areas. The specialised equipment shall

include (but not be limited to) the following essential items:-

(a) A laybarge, mounted on which shall be: linepipe racks, arc-welding machines, a

heavy duty crane, heavy duty winches, electric generators, air , compressors and all necessary

power operated hand tools.

(b) A pump barge, equipped with a large capacity flushing pump, high pressure test pump,

air compressors and all necessary pig units for flushing, cleaning, proving, testing,

clearing and swabbing the sections of pipeline concerned in the repair Works.

(c) A spud barge with boom and bucket mounted for dredging and a heavy duty winch

for operating spuds.

(d) A floating work platform


16/17

-16-

(e) A water barge

(f) A tug boat for equipment movements

(g) House boats for staff and workers

(h) Launches and dinghies for shuttle service

26.12.3 Preliminaries and Company Representatives

The Contractor shall be advised of the point(s) of leakage by the Company and shall obtain the

necessary Permits-to-Work before starting any repair work. The pipeline or flowline

concerned will be closed down, isolated and bled to zero pressure by Company Operations

Personnel prior to commencement of any work. Two Company Representatives, one from

Engineering and another from Production, shall be present during the execution of the repair

Works and, the Contractor shall afford them full access, facilities and assistance as necessary

during their attendance and supervision of the Works.

26.12.4 Clearing the Line

The Contractor shall pig the line so as to displace any residual oil or gas and flush it out with

clean water. In the case of flowlines, the displaced oil residues and flushing water shall be

discharged into the oil saver of the respective flowstation. Otherwise the Contractor shall

displace, collect, transport and dispose of the line fill as directed by the Company and Clause

26.9.2 herein . The Contractor shall ensure that no oily water spillage contaminates the

surrounding swamp or marsh during preparations for repair work. The quantity of flushwater

used shall be at least six times the volumetric capacity of the line and the Contractor shall

continue pigging and flushing the line until the Company Representative is satisfied that theline is clear of residual gas. Tests for residual gas in the line shall be made at the water exit

end during flushing operations and at the leak location (if possible). Hot water flushing may be

necessary for removing waxy crude and shall be carried out by the Contractor, if necessary, at

no extra cost to the Company.

26.12.5 Repair Procedure

The Contractor shall carry out excavation/dredging work in the vicinity of the pipeline as

necessary and then, using broad band slings, carefully lift the damaged section(s) with a crane,

taking care not to overstress the line at any point.

The leaking, damaged or suspect parts of the line shall then be replaced or repaired in

accordance with the procedures detailed under Specification Sections 26.8 and 26.9 herein. All

welds shall be subject to 100% radiographic examination.

After the tie-in welds have been satisfactorily completed, coating and wrapping the field joints

and all unprotected surfaces (and repairs to any damaged or suspect areas of the wrapping

protection) shall be carried out to the satisfaction of the Company Representative.

The repaired line section shall then be lowered back into the trench, refilled with water and

hydrostatically tested in accordance with Standard Construction Specification S-29 (PressureTesting). The required test pressure will be advised by the Company. The specified test

pressure shall be held for 24 hours. The test pressure shall never exceed 150 bars (2160 psig)

for lines of ANSI 600 lb rating.


17/17

17

After pressure testing has been satisfactorily completed the pipeline trench or slot shall be

backfilled in accordance with the instructions of the Company Representative.