Chevron Maintenance & Inspection Procedures

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

PIPE REPAIR Procedure Number: MIP-403

© COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

CONTENTS PIPE REPAIR MIP-403 Section

Title

Page

1.0

Purpose

403 - 1

2.0

Scope

403 - 1

3.0

Prerequisites

403 - 2

4.0

Process Overview

403 - 4

5.0

Instructions

403 - 5

5.1

Evaluate and Classify the Extent of the Pipe Defect

403 - 5

5.2

Select Repair Method

403 - 6

5.3

Temporary Pipe Repairs

403 - 6

5.4

Site Safety Plan and Work Over

403 - 7

5.5

Permits and Notifications

403 - 7

5.6

Pipe Preparation

403 - 8

5.7

Patch Installation

403 - 9

5.8

Mechanical Applied Full Encirclement Sleeves

403-10

5.9

Full Encirclement Sleeve (Full Wrap)

403-12

5.10

Composite Sleeve

403-13

5.11

Document the Repair

403-15

5.12

Backfilling

403-15

5.13

Right-of-Way Clean Up, Restoration and Pipeline Marking

403-16

© COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

6.0

Roles and Responsibilities

403-18

7.0

Reporting Requirements

403-17

8.0

Documentation and Record Retention

403-19

Appendix A

Glossary

B

Pipe Defects

C

Pipe Repair Options

D

Fiberglass Composite Repair Details

© COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

1.0

Chevron Pipe Line Company

PURPOSE

The purpose of this procedure is to: •

assure pipe repairs are performed safely and properly; and

•

comply with 49 CFR 192 and 195; in Texas, the Texas Railroad Commission, and applicable state pipeline safety regulations.

2.0

SCOPE

2.1

Personnel Covered By This Procedure

This procedure applies to all personnel, Company and contractor, who are involved in pipe repairs to regulated pipelines operated and/or maintained by Chevron Pipe Line Company (CPL) or any of the other legal entities managed under the direction of CPL, herein after referred to as "Company".

2.2

Activities Covered By This Procedure

This procedure covers the repair of regulated non-leaking pipelines. Methods covered include: •

mechanical applied full encirclement installation;

•

welded sleeve or welded full encirclement installation; and

•

composite sleeve installation.

2.3

Activities Excluded From This Procedure

2.3.1

This procedure does not cover pipe repair activities for non-regulated gathering facilities or pipelines.

2.3.2

This procedure does not cover pipe repair activities mandated by local, state, county, or parish regulations. Refer to the System manual covering the location needing repair.

2.3.3

This procedure does not cover repairs to leaking pipelines.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

2.4

References

For a list of reference documents and publications included in 49 CFR 192 and 195, refer to the latest edition of the U.S. Department of Transportation, CFR 49, Pipeline Regulations. References listed in 49 CFR 192 Appendix A and 49 CFR 195.3 include the following: •

API Specification 5L, "Specification for Line Pipe";

•

API Standard 1104, "Welding of Pipelines and Related Facilities";

•

ASME/ANSI B31.4, "Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohols"; and

•

AMSE/ANSI B31.8, "Gas Transmission and Distribution Piping Systems".

3.0

PREREQUISITES

3.1

Personnel and Training Requirements

3.1.1

Personnel performing this procedure must be: a) able to recognize and report pipeline damages or anomalies that warrant pipe repairs; b) Hazwoper trained and certified to level 3 to make pipe repairs;

Note:

Contractor personnel who will not perform any functions associated with "emergency response" situations are EXEMPT from this prerequisite.

c) capable of implementing pipe repairs in compliance with all regulatory requirements including 49 CFR 192 and 195; d) trained, qualified and experienced in making the specific pipe repairs being implemented; e) knowledgeable of the specific properties, characteristics and potential hazards of the gases or liquids contained in the pipelines requiring pipe repairs; f) qualified per API Standards 1104 for circumferential butt welds and API RP 1107 for in-service maintenance welding;

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

g) familiar with the CPL-3 process (MIP-103) for data capture, documentation and reporting; h) knowledgeable and capable of complying with the safety procedures listed in section 3.2; i) trained and competent in the use of personal protective equipment; and j) qualified to perform this task under the CPL Operator Qualification (OQ) plan. 3.1.2

The Person-in-Charge must be Hazwoper trained and certified to Level 3 and/or Level 5.

3.1.3

Personnel involved in excavations must be qualified as a "Competent Person."

Note:

3.2

See Appendix A for definitions of Person-in-Charge and Competent Persons.

Safety Requirements

3.2.1

All pipe repairs must be supervised by a qualified Person-in-Charge who is aware of the hazards and proper procedures for the type of repair being performed.

3.2.2

Personnel performing pipe repairs must comply with the following procedures as applicable: a) Confined Space Entry (HES-201) b) Excavation (HES-202) c) Lockout/Tagout (HES-203) d) Hot Work Permits (HES-205) e) Respiratory Protection (HES-502) f) Gas Testing and Analysis (HES-209) g) Safe Handling of Asbestos Containing Material (HES-703) h) Safe Work Permit (HES-204) These and other safety procedures can be found in the HES Procedures manual.

3.2.3

Personnel performing pipe repairs must be fit tested and trained to use respiratory equipment.

3.2.4

A job site safety plan must be completed prior to starting pipe repairs.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

3.3

Repair Material Requirements

All repair material must meet the design requirements for the system for which the material is used and be compatible with the product transported in the system.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

4.0

PROCESS OVERVIEW Pipe repair needed

Install suitable temporary repair

Evaluate the pipe defect

Select type of permanent repair

Complete site safety plan

Notify appropriate agencies, landowners and one-call systems and obtain any necessary permits

Prepare the pipe for repair

Repair pipe

Document repair

Page 403-5 © COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

5.0

INSTRUCTIONS

5.1

Evaluate and Classify the Extent of the Pipe Defect or Damage

When a pipe is determined to be damaged or defective, the Field Team Member performs the following steps: 5.1.1

5.1.2

Evaluate the damaged or defective pipe and classify the extent of the damage/defect (see Appendix A for definitions): •

Leaking or non-leaking

•

Severe

•

Superficial

•

Longitudinal extent

•

Deep or shallow

Classify the type of damage or defect: a)

Manufacturing defect

b)

Environmental/corrosion

c)

Construction caused

d)

Damaged by outside force

e)

Involves seam or girth weld

f)

Involves body of pipe only

5.1.3

Report findings to the Field Team leader.

5.1.4

Determine type of repair best suitable for the pipe based on operational limitations, the extent of the damage, and the type of damage.

5.1.5

Initiate a CPL-3 per MIP-103 for documentation.

5.2

Select Repair Method

5.2.1

If a temporary repair is needed, see Section 5.3.

5.2.2

Consult the matrix in Appendix C for an evaluation of permanent pipe repair options. Consider the following criteria before making a permanent repair:

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

5.2.3

a)

Regulatory compliance requirements;

b)

System downtime;

c)

Repair materials, labor and downtime costs;

d)

Scheduling;

e)

Safety;

f)

Best method of repair for the specific situation, and;

g)

Positive isolation or double block and bleed requirements.

The Asset Integrity Team’s Pipeline Integrity Technologist, Technical Services’ Field Technical Support Representative or other subject matter expert assistance may be needed to select and develop the best repair technique based on: •

complexity/uniqueness of the repair technique;

•

experience within the Field Team with similar repair techniques; and

•

extent of the damage/defect to the pipeline.

The Field Team leader determines whether technical assistance is necessary, and if so, consults with the appropriate subject matter experts. 5.2.4

If the defect will be removed by hot tapping, refer to the Hot Tapping procedure (for liquids, Appendix 500A in the EPC General Procedures manual and for gas, Section 3.8 of the Core Gas Pipeline O & M manual). If the damaged or defective section of pipe will be replaced, refer to the Pipe Replacement procedure (MIP-404).

5.2.5

Any repair method that varies from those listed within this document or that varies from the installation procedures listed within this document must have written approval from the Technical Services Manager.

5.3

Temporary Pipe Repairs

In situations where a temporary repair is necessary, a permanent repair must be performed within one year of the temporary repair. The following methods may be used to temporarily repair a pipeline defect: •

U-bolt and clip (saddle).

•

Mechanical split sleeve clamp (full encirclement, e.g. Plidco sleeve type): This type of repair may either be permanent or temporary, but to be considered permanent it must be fully welded except where it meets other guidelines listed in Section 5.8. For some offshore crude oil locations, non-welded Plidco-type clamps are allowed as permanent connections. See Section 5.8 for installation guidance. Page 403-7

© COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair Note:

•

With either type of repair clamp, the gasket material used must be compatible with the product(s) in the pipeline and the pressure rating must be adequate for the system. A composite sleeve may be used as a temporary repair for internal corrosion. Composite sleeves are considered a permanent repair for some external corrosion and dents. See Section 5.10 for full installation guidance.

5.4

Site Safety Plan and Work Order Approval

5.4.1

The Person-in-Charge completes a site safety plan detailing how the pipe repair will be performed. The Field Team leader approves the pipe repair plan with input from the Asset Integrity Team (Pipeline Integrity Technologist), Technical Services, or other subject matter experts if necessary.

5.4.2

The Field Team leader prepares or delegates the preparation of a work order. Depending upon the estimated cost of the pipe repair project, the Field Team leader approves the work order or submits it to the Profit Center Manager for approval.

5.4.3

After obtaining approval for the pipe repair, the Field Team leader ensures that the following are completed as appropriate:

5.5

•

bid specification;

•

contracts for services and materials;

•

material and equipment acquisitions;

•

operational requirements (reduce pressure and/or flow rates);

•

plans meet regulatory requirements; and

•

Contractors and company personnel are all OQ qualified on work procedures.

Permits and Notifications

The Person-in-Charge ensures that the following notifications are made and appropriate permits are obtained. Contact the Permit Coordinator for assistance if needed. 5.5.1

Determine whether permits are required by law, regulation, easement, or other requirement. This person will contact the proper authorities for required permit(s) and submit the necessary forms to secure the permit(s). After receiving the permit(s), review and communicate the conditions of the permits with the appropriate personnel to ensure that all conditions are understood and properly executed. If you need assistance with permitting, contact the Permit Coordinator.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

Permits may be required for, but not limited to, pipe repairs in the following locations or scenarios: a) county roads; b) state roads; c) waterways/water crossings; d) railroads; e) where there is stormwater; f) where there is hydrotest water; g) where there is flaring or burning; h) within city or town limits; i) inside a refinery or plant facility; j) Native American lands and reservations; k) state and/or federal lands, parks and game reserves; l) interstate highways; m) environmentally sensitive areas, including wetlands; and n) construction areas where Environmental Protection Agency (EPA) or National Pollutant Discharge Elimination System (NPDES) water discharge permits are required. For maintenance work permit locations, see HES-101. 5.5.2

Notify landowners of the pipe repairs.

Note:

Generally, right-of-way easements permit Company the right to enter a right-of-way to do maintenance work without notifying the landowner. However, to maintain good landowner relations, Company personnel should always contact the owner or tenant before entering the property. If requesting permission to enter land that is not a Company rightof-way, the team member should inform the landowner of the work that needs to be performed and ask about special requirements and the best property access. Company personnel must ensure that all gates are closed, no livestock escapes, all roads are left in good condition, and property damage is minimal.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair 5.5.3

Notify the Customer Service Center (CSC) of the details of the pipe repair plans. Request CSC to issue pipeline orders for the pipe repair work as necessary.

5.5.4

Notify the One-Call system, appropriate agencies and utility companies as necessary.

5.6

Pipe Preparation

5.6.1

Support the pipe to prevent movement during installation. Remove as little dirt as possible underneath the pipe and use sandbags or skids to minimize stress concentration.

5.6.2

Remove all coating from the section of pipe to be repaired. Sandblast or wire brush the external surface of the pipe to remove dirt, rust, scale and other foreign materials. In addition, at each end of the sleeve-to-pipe connection, machine buff at least three inches on each side of the connection.

Note:

If the coating contains asbestos, follow the Safe Handling of Asbestos Containing Material procedure (HES-703).

Warning:

Grinding must not be used to clean the pipe or sleeve.

5.7

Patch Installation Although welded patches are an industry accepted method for repairing certain pipelines and have been used for repairing Company pipelines in the past, this method is not recommended for Company pipeline repairs today or in the future. Existing patch repairs may be acceptable only if they meet all current regulatory specifications and applications

5.8 5.8.1

Mechanical Applied Full Encirclement Sleeves A mechanical applied full encirclement sleeve is a sleeve manufactured with matching halves and sealing elements for both longitudinal and circumferential sealing of the pipe. It has stud bolts and nuts for installation onto the pipeline. In most cases, mechanical applied full encirclement sleeves used for permanent repairs must be welded to the pipe. On offshore crude oil pipelines, non-welded Plidco-type clamps are allowed as permanent repairs where they eliminate the need for lifting the pipeline to the surface. However, welded sleeves are still the preferred method for repair. Mechanical applied full encirclement sleeves do not need to be welded for the following: a) Temporary repairs. b) DOT 192 regulated gas transmission pipelines which are:

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair •

submerged offshore pipelines; or

•

submerged pipelines in inland navigable waters when the encirclement sleeve meets the design requirements of the pipeline for which it is installed.

c) DOT 195 regulated submerged offshore crude oil pipelines when the encirclement sleeve meets the design requirements of the pipeline for which it is installed. 5.8.2

Prepare the pipe as described in section 5.6 of this procedure.

5.8.3

Coat all exposed surfaces of the gasket with a lubricant that is compatible with the seal and product.

5.8.4

Clean and lubricate all studs and nuts, and prove the nut is free and turns easy prior to the installation.

5.8.5

Assemble the sleeve loosely around the pipeline to one side of the pipeline defect, matching the mating identified ends recommended by the manufacturer. Slide the sleeve over the defect, being careful not to damage the girdering and packing. Center the sleeve over the pipeline defect. Hand tighten the studs and nuts.

5.8.6

All studs and nuts should be uniformly torqued as recommended by the sleeve manufacturer. Maintain an equal gap between side bars while tightening the bolts.

5.8.7

Complete assembly by rechecking tightness of all the studs to the manufacturer's torque recommendations.

5.8.8

Depending on the manufacturer, the side bars are generally gapped approximately 1/8" when the sleeve is fully tightened.

5.8.9

After the mechanical sleeve has been installed and the pipeline has been repressured, check the sleeve to ensure there are no leaks. Use soap or a combustible gas indicator (CGI) for testing. If leaks are detected, return to step 5.8.7 above.

5.8.10 If the sleeve will be welded to the pipe, complete the following steps: 5.8.10.1

Warning:

Reduce the pressure by one third of the normal operating pressure to allow the sleeve to share hoop stress. In cases where the product or operation does not allow the pressure to be dropped by one third, consult the Asset Integrity Team (Pipeline Integrity Technologist) or Technical Services before continuing. Product flow must be maintained to permit cooling and prevent the build-up of gases.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair 5.8.10.2

After the pressure is reduced, complete final tightening of the sleeves. The gap of the longitudinal weld groove is critical. The gap must be 1/16 inch on each side. Reposition the sleeve or grind the edges to achieve the proper gap.

5.8.10.3

Weld the sleeve per the Pipe Welding procedure (MIP-407) and the sleeve manufacturer’s recommendation. The sleeve installation welding procedure is a low hydrogen API1107 process. Use absolutely dry low hydrogen electrodes and carefully control the size and shape of the circumferential fillet weld. The leg length of the fillet weld should not be less than the wall thickness of the pipe. Strive for a concave faced fillet weld, with streamlined blending into both members; avoid notches and undercuts. The smoother and more streamlined the weld, the greater the resistance to fatigue.

Note:

The worst possible shape would be a heavy reinforced convex weld with an undercut.

5.8.10.4

Welding should proceed slowly and caution should be observed so the welding does not overheat the packing and sealing elements. Sequence the welding so that the heat is not concentrated in one area.

5.8.10.5

Fillet-weld the sleeve ends to pipe.

5.8.10.6

Seal-weld the sleeve side openings.

5.8.10.7

Re-torque the studs and nuts.

5.8.10.8

Seal-weld around the bottoms of the nuts to the side bars.

5.8.10.9

Seal-weld the nuts to the studs (see the manufacturer's material list for ASTM metal composition of studs and bolts).

Warning: 5.8.10.10

Product flow must be maintained to permit cooling and prevent the build-up of gasses. Inspect the welded sleeve per MIP-407.

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

5.9

Full Encirclement Sleeve (Full Wrap)

5.9.1 A full encirclement sleeve (full wrap) is a metal wrap installed around pipe for reinforcement and containing pressure. The full sleeve is produced by welding together two half sleeves around pipe. Sleeves are only permitted to be installed on pipe having a wall thickness between .188 and .750 inches. There are two types of full wrap encirclement sleeves: •

Type A is longitudinally welded along its connecting edges but not welded to the pipe at the ends.

•

Type B is welded on the ends to the carrier pipe in addition to the longitudinal weld. Type B is the recommended installation because it is pressure containing.

Note:

Consult the Asset Integrity Team (Pipeline Integrity Technologist) or Technical Services before using Type A sleeves.

Sleeve material is listed in the Pipe Welding procedure (MIP-407) by pipe material/sleeve material classification. See Section 5.9.10 and 5.9.11 for girth weld and long repair lengths. For assistance, contact the Asset Integrity Team (Pipeline Integrity Technologist). 5.9.2

The sleeve material wall thickness must be calculated to accommodate the full design pressure of the mainline pipe on which it is installed. Use the following formula: Ts =

Tp S p D p D p S s - 2 S p Tp

Where: Ts= Minimum sleeve thickness in inches (at full design pressure) Tp= Minimum pipe thickness in inches (at full design pressure) Ss= SMYS for the sleeve material in psi Sp= SMYS for the pipe material in psi Dp= Outside diameter of the pipe in inches The sleeve thickness must be greater than or equal to the pipe wall thickness. Sleeve material of higher SMYS than the pipeline shall have a wall thickness equal to or greater than the original pipeline design thickness. No credit shall be taken for the increased SMYS of the sleeve. If the sleeve thickness is greater than

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair the pipe thickness, the ends of the sleeve must be chamfered at a 45 degree angle to a thickness equal to the pipe. 5.9.3

Inspect the wall thickness. The integrity of the pipe at the fillet weld location must be verified. This may be done using an ultrasonic thickness gage and by visual inspection. The minimum pipe wall thickness at the location where the sleeve will be welded to the pipe is .188 inches.

5.9.4

Prepare the pipe as described in section 5.6 of this procedure.

5.9.5

Prepare the sleeve and fit it to the pipe.

5.9.5.1 Warning:

Wire brush the internal surface of the sleeve to remove dirt, rust, scale, and other foreign materials. Grinding must not be used to clean the pipe or sleeve.

5.9.5.2

A factory manufactured half sleeve is usually ten feet long and may be cut to the required length in the field. The minimum length for a sleeve is four inches per DOT. However, Chevron Pipe Line recommends no sleeve shall be less than 12” long. Bevel the sides for butt welding and plane cut the ends for fillet welding. If any adjustments are made to the half sleeve, the sides must be re-beveled and the ends planed.

5.9.5.3

A backing strip is recommended at the longitudinal butt weld to protect the pipe from weld damage. The strip must be a minimum of 16 gauge (.0625 inch thick) mild carbon steel cut to the length of the half sleeve. Tack weld the strips to the bottom half of each side, with welds approximately a half inch long and spaced twenty-four inches apart. Follow the sleeve manufacturer's instructions, if available.

5.9.5.4

When sleeves are used to repair dents, fill the dent with a hardening filler material such as epoxy or automobile body putty before installing the sleeve.

5.9.5.5

Place the bottom sleeve, with the backing strips attached, under the pipe with the edges of the strip barely touching the sides of the pipe. Position the top sleeve over the pipe using wedges on the ends of the top sleeve's longitudinal seam to provide clearance for the backing strip to fit underneath the top half.

5.9.5.6

Plate clamps can be used for positioning the top sleeve and can be removed when the proper position is obtained. Spreader bar rigging may be used when handling long half sole sleeve sections.

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair 5.9.5.7

Once the half sole sleeves are in close proximity to the pipe, position the chain clamps around the half sole. Chain clamps should be fabricated of a diamond, double roller type chain. The tightening mechanism must be supported by a metal shoe contoured to the shape of the half sole/pipe.

5.9.5.8

Tighten the clamps at an equal rate on each clamp until the top half sole has cleared the backing strips. At this point, the wedges can be removed. Continue tightening the clamps until the half sole is firmly in position.

Note:

5.9.5.9

5.9.6

Remove any hydrocarbon film on the sleeve and pipe at the fillet weld location with a suitable solvent. This is an important step and integral to ensuring a low-hydrogen weld!

Reduce the pressure by one third of the normal operating pressure to allow the sleeve to share hoop stress. In cases where the product or operation does not allow the pressure to be dropped by one third, consult the Asset Integrity Team (Pipeline Integrity Technologist) or Technical Services before continuing.

Warning: 5.9.7

Before tightening the half sole for the final time and welding the longitudinal seams, the pipeline pressure must be reduced to ensure the gap between the pipe and sleeve is at a minimum and the sleeves are load bearing.

Product flow must be maintained to permit cooling and prevent the build-up of gasses.

After the pressure is reduced, complete final tightening of the sleeves. The gap of the longitudinal weld groove is critical. The gap must be 1/16 inch on each side. Reposition the sleeve or grind the edges to achieve the proper gap.

5.9.8

Weld the sleeve per the Pipe Welding procedure (MIP-407). The sleeve installation welding procedure is a low hydrogen API-1107 process. Use absolutely dry low hydrogen electrodes and carefully control the size and shape of the circumferential fillet weld. The leg of the fillet weld should equal 1.4 times the wall thickness of the pipe. Strive for a concave faced fillet weld, with streamlined blending into both members; avoid notches and undercuts. The smoother and more streamlined the weld, the greater the resistance to fatigue. The longitudinal welds must be completed before welding circumferentially type "B" full encirclement sleeves.

Note:

The worst possible shape would be a heavy reinforced convex weld with an undercut.

Warning:

Product flow must be maintained to permit cooling and prevent the build-up of gasses.

5.9.9

Inspect the welded sleeve per MIP-407. Page 403-15

© COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair 5.9.10 If the area to be sleeved contains a girth weld that may provide difficulty with fitting a plain sleeve, an expanded sleeve (sometimes called a pumpkin) can be installed providing the material meets the requirements listed in MIP-407. 5.9.11 If the area to be sleeved is longer than the sleeve material and additional pieces must be used, use one of the following methods:

5.10

•

Butt weld the sleeves together at each end and radiographically inspect the butt welds prior to installing the sleeve halves on the pipeline.

•

Leave a minimum of ½ pipe diameters (or 4” minimum) between the two sleeves.

•

Butt the sleeves together and install another sleeve over those using the proper sleeve weld procedure listed in MIP-407. The overlapping sleeve must be at least 12” long and centered over the primary sleeve ends. The overlapping sleeve must be oversized (larger inside diameter) and be able to cover the entire circumference of the primary sleeve. The overlapping sleeve material and thickness must be calculated using the larger outside diameter of the primary sleeves.

Composite Sleeve Repair

5.10.1

A composite sleeve repair is a full-encirclement fiberglass composite wrap installed around the pipe using multiple layers. One of the most well-known composite sleeve repairs is called “Clockspring”. The sleeve is manufactured from high tensile strength corrosion resistant fiberglass with a filler material. This type of repair is produced by wrapping the product around the pipe and attaching it to the pipe and itself with an adhesive. At this time, “Clockspring” is the only composite repair sleeve approved for use by CPL.

5.10.2

Composite sleeves are permitted: •

For repairing external metal loss defects (except for locations with metal loss of 80% of pipe wall thickness or greater)

•

For repairing external metal loss in bends with a radius of 3D or greater (custom repair)

•

For repairing external metal loss at girth welds (except for locations with metal loss of 50% of pipe wall thickness or greater or a width of 30% of circumference or greater)

•

For repairing plain dents (unless cracks are evident). Visual inspection and either magnetic particle or dye penetrant testing should be used to look for cracking. Dents with cracking or stress concentrators, such as

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

gouging, grooving or metal loss, cannot be repaired with a composite sleeve. •

For repairing 4” through 56” diameter pipe (with a minimum wall thickness of .068”)

Composite sleeves are not permitted: •

For repairing leaking pipe

•

For repairing internal corrosion

•

For leak prevention from through-wall internal pitting

•

For repairing dents in bends and dents with cracking or stress concentrators, such as gouging, grooving or metal loss

•

For repairing linear crack-like defects such as stress corrosion cracking

•

For repairing defects with sharp edges

•

For repairing gouges

•

Where there is a concern of the pipe pulling apart

•

For repairing girth welds with crack-like defects

•

For repairing girth welds that fail code-required weld quality requirements

•

For repairing piping with a continuous operating temperature greater than 140F or spiking temperature greater than 180F (unless manufacturer has a product with a higher temperature adhesive and resin).

Composite sleeves should be: •

Installed per manufacturer’s guidelines

•

Installed by qualified personnel trained and certified by the specific composite sleeve’s manufacturer or a trainer certified by the manufacturer. The installation of composite sleeves is a covered task under the Operator Qualification Rule (Task 40.3). Company personnel may train and qualify additional installers if they have been specifically trained and certified as a trainer by the composite repair kit manufacturer. Installers must re-certify annually by written test per the sleeve manufacturer’s guidelines. Installers who have not installed a composite sleeve within a 15 month period must be recertified by a qualified instructor by written test and by performing a sample installation. Page 403-17

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair Note:

5.10.3

Note:

5.10.4

See Appendix C or consult the Asset Integrity Team (Pipeline Integrity Technologist) or Technical Services for more clarification on the use of these sleeves. The sleeve design is established by the repair sleeve manufacturer. The proper number of wrap layers is also determined by the sleeve manufacturer. The length of sleeve varies from manufacturer to manufacturer, but Chevron Pipe Line recommends no repair sleeve shall be less than 11 1/2” long (length refers to length along the pipeline) except for bend repair and on each side of a girth weld repair. Only material supplied with a composite sleeve repair kit may be used. No substitutes are allowed. This includes dent filler also. Do not use auto body filler or Bondo. Inspect the wall thickness. The integrity of the pipe at each end of the sleeve must be verified. This may be done using an ultrasonic thickness gage and by visual inspection. The minimum pipe wall thickness at each end of the sleeve is .068 inches. Extend or move the sleeve to ensure that this minimum is maintained.

5.10.5

Prepare the pipe as described in Section 5.6 of this procedure. The pipe must be cleaned of all coating, oil, corrosion products, dirt or foreign material by sandblasting, wire brush, or scrapers. Coatings containing zinc or coal tar must be completely removed from the surface as they inhibit the curing and bonding properties of the composite’s adhesive. The pipe must be bare, clean and dry and should meet the standard of a NACE 3 finish. An Anchor Pattern is required. Any sharp defects must be re-shaped to “blunt” condition. Filler material should be applied to the metal loss area to restore the original pipe contour. This includes any longitudinal weld bead above the contour of the pipe and leading edge of the starter pad. A slight excess of filler may be applied to the metal loss area to be repaired prior to installation of the repair sleeve. When sleeves are used to repair dents, fill the dent with a hardening filler material provided by the composite sleeve manufacturer before installing the sleeve. A temporary sleeve will also be installed to ensure that the contour of the dent and pipe are the same.

5.10.6

Prepare to install the sleeve and fit it to the pipe. Reduce the pressure by one third of the normal operating pressure to allow the sleeve to share hoop stress. In cases where the product or operation does not allow the pressure to be dropped by one third, consult Technical

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

Services before continuing. The pressure should stay reduced until the sleeve installation is complete and allowed to cure. 5.10.7

The repair sleeve, and all its components, shall be installed in strict accordance with the manufacturer’s instructions by qualified installers. The repair sleeve must extend a minimum of 2” beyond the defect. Sleeves can be butted up for long defects. Composite repair sleeves shall not be installed directly over the butt weld joint fusion line. Composite material repair sleeves shall only be installed at ambient temperatures between 32 degrees Fahrenheit and 120 degrees Fahrenheit (for temperatures lower than 32 degrees Fahrenheit, consult manufacturer). The pipe shall be dry and protected with tarps or shelters in conditions of rain, high humidity, blowing sand and dust, etc. This method of permanent repair shall be limited to the calculated length indicated by the manufacturer’s software analysis, measured along the pipeline. When the defect is located adjacent to a girth weld, it will be necessary to install a four-wrap sleeve on each side of the girth weld, apply filler material in the area between the wraps, allow molded material (use of single wrap composite) to cure, then install a full-size eight-wrap sleeve over the defect.

5.10.8

Because most of the composite sleeves do not contain carbon steel, they are not detectable by an MFL (magnetic flux leakage) smart pig inspection tool. For the future location of the repair sleeve, a thin metal band should be installed on the pipe near each end of the sleeve.

5.10.9

All metal loss defects shall be carefully measured and documented to ensure they meet the criteria for suitability to repair.

5.10.10

The shelf-life of the adhesive and the filler material should be checked to make sure it is less than 1 year old. If the shelf-life exceeds 1 year, properly dispose of the material within the guidelines set forth in HES-707 through HES-710.

5.10.11

Visually inspect the sleeve upon completion of the installation. There shall be no gaps or voids between the pipe and the sleeve or between the sleeve layers. It may be necessary to fill these gaps with adhesive or remove the existing sleeve if the gaps or voids cannot be removed.

5.10.12

Upon completion of the curing (at least 2 hours or with a Shore Hardness test of 40) of the sleeve adhesive, the entire repair area shall be sealed. The sleeve and adjoining bare pipe shall be sealed by using an approved pipe coating. (See MIP-503 for coating information.) The sleeve ends may Page 403-19

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Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair require a filler tape or coating strips applied to effect a smooth transition in preparation for applying the pipe coating. Any extra adhesive or filler except those in unopened containers should be disposed of within the guidelines set forth in HES-707 through HES-710. 5.10.13

5.11

Document the Repair

5.11.1

5.12

See Appendix D for sample applications for girth weld repair, dent repair, bend repair and marking repair locations.

Document the repair on a CPL-3 and forward a copy to the Data Management Specialist.

Backfilling

5.12.1

When a ditch for a pipeline is backfilled, it must be backfilled in a manner that a) provides firm support under the pipe and b) prevents damage to the pipe and pipe coating from equipment or from the backfill material.

5.12.2

Reinstall or repair any broken or damaged cathodic protection test stations affected during excavation before backfilling.

5.12.3

Check backfill for rocks and determine whether rock shield needs to be installed around the pipe. If rock shield is used, install the rock shield per the manufacturer's specifications. If rock shield is not used, shade or cover the pipeline three inches deep with rock-free dirt ensuring that the dirt is firmly compacted around the sides and top of the pipeline.

5.12.4

Backfill to cover the pipeline with six inches or more of select dirt (select dirt may contain some small rocks).

5.12.5

Continue to backfill until there is a six to twelve inch tall crown over the pipeline ditch to allow for any settling of the soil/dirt.

5.13

Right-of-Way Clean Up, Restoration and Pipeline Marking

5.13.1

Pick up and remove all trash and debris from the work area and right-ofway.

5.13.2

Measure the right-of-way damage area and document for submission for payment.

5.13.3

Return the right-of-way to as close to its original condition as possible or as specified.

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair 5.13.4

Construct water breaks or specified erosion control as required. (Refer to MIP-203, Right-of-Way Erosion Prevention and Repair.)

5.13.5

Re-vegetate the right-of-way, as required, per the tenant approval of the revegetation plan. (Refer to MIP-202, Right-of-Way Vegetation Maintenance.)

5.13.6

Grade and/or repair private roads to restore them to as close to their original pre-construction condition as possible.

5.13.7

Rebuild or repair fences, gaps and gates to return them to their original condition.

5.13.8

Ensure that the pipeline(s) is properly marked and identified in the right-ofway per the Pipeline and Facility Marking procedures (MIP-204). Document the marker location(s) as necessary on the CPL-3 form.

6.0

ROLES AND RESPONSIBILITIES

6.1

The Team Leader is responsible for:

•

ensuring that Field Team members and the Person-in-Charge have the proper training and qualifications to direct and perform pipe repairs;

•

requesting technical assistance as needed;

•

approving the selected pipe repair technique and installation method; and

•

ensuring that all pipe repair work is performed properly, safely and in compliance with applicable governmental regulations and Company policies and procedures.

6.2

The Person-in-Charge is responsible for:

a) ensuring a site safety plan is completed before beginning the repairs; b) ensuring that proper procedures are followed for all repairs; c) ensuring only qualified personnel are involved in pipe repair; d) selecting the type of repair with assistance from the Team Leader and Subject Matter Experts as needed; e) ensuring proper permits are obtained; f) ensuring landowners and/or tenants, One Call systems, utility companies, pipeline companies and others are necessary have been notified;

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair g) notifying the Customer Service Center of the pipeline repairs and requesting the Customer Service Center issue pipeline repair orders, as necessary; and h) ensuring the pipe repair work is accurately documented.

6.3

Team Members are responsible for:

a) complying with all applicable Company safety, welding and pipe repair procedures when performing pipe repairs; b) only performing procedures for which they are qualified; c) identifying, investigating and evaluating pipeline conditions that require pipe repair and reporting the conditions to the Field Team Leader; d) ensuring permit applications are prepared; e) notifying landowners and/or tenants, One Call systems, utility companies, pipeline companies and others are necessary; f) performing and/or inspecting the pipe repair work; g) properly documenting the pipe repair; h) performing right-of-way restoration, vegetation maintenance and pipeline marking work; and i) determining if right-of-way damage claims are valid and coordinating with the rightof-way specialist to negotiate a fair settlement.

6.4

The Asset Integrity Team (Pipeline Integrity Technologist), Technical Services, HES and other Subject Matter Experts are responsible for providing assistance and support as requested.

7.0

REPORTING REQUIREMENTS

7.1

Pipe Repairs in the Gulf Coast Region

For offshore pipeline repairs in Federal (OCS) waters, submit a plan of the repair to: U. S. Department of the Interior Minerals Management Services Gulf of Mexico OCS Region

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

7.2 7.2.1

Chevron Pipe Line Company

Pipe Repairs in Navigable Waters in the Western Region In the State of Utah, contact: State of Utah Department of Natural Resources Division of Water Rights

7.2.2

In the State of Colorado, contact: Colorado Department of Natural Resources Army Corp. of Engineers

7.2.3

In the State of Idaho, contact: Army Corp. of Engineers Idaho Department of Water Resources State office

7.2.4

In the State of Oregon, contact: Oregon Division of State Lands Eastern Region Local Corp. of Engineers Department of the Army Regulatory branch

7.2.5

In the State of Washington, contact: Department of Natural Resources Aquatic Resource Division Local Corp. of Engineers Department of the Army Regulatory Branch, Seattle District

7.2.6

To report repairs in California navigable waters, contact the US Coast Guard.

7.2.7

To report emergency leak repairs in California, contact: Office of State Fire Marshall Pipe Line Safety Division

7.3

Pipe Repairs in Navigable Waters in the Central Region

7.3.1 In the State of Texas, contact: Corp. of Engineers Page 403-23 © COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

Reviewed/Revised 9/05

MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair Department of the Army Fort Worth District Attn.: CESWF-OD-R 7.3.2

In the State of New Mexico, contact the New Mexico Department of Surface Water Quality

8.0

DOCUMENTATION AND RECORD RETENTION

8.1

Required Documentation

The CPL-3 form (MIP-103) is used to document the pipeline repair.

8.2

Document Storage and Retention Time

All repair documentation, including CPL-3, Welder Qualification, Clock-Spring Installation Qualification, Pipe Mill Certification Reports, Sleeve Material Mill Reports, Hydrotest Records, etc. must be maintained for the life of the pipeline or facility for which the pipe repairs were made. The original completed CPL-3 form should be forwarded to the Data Management Specialist.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

APPENDIX A - GLOSSARY Person-in-Charge A person who has been designated to see that the pipe repair is performed properly. This can only be a Company employee.

Competent Person A person who has received the training required to perform pipe repairs and excavation.

Insert Patches A small piece or portion of pipe not cylindrical in shape used to replace an identical piece or portion of pipe which has been cut out for repairs.

Mechanical Sleeve Plidco type sleeve with bolt closures and o-ring type seal which can be used for repairs without welding.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

APPENDIX B - PIPE DEFECTS MANUFACTURING DEFECTS Lap Fold of metal which has been rolled or otherwise worked against the surface of rolled metal, but has not fused into sound metal.

Pit A depression resulting from the removal of foreign material rolled into the pipe surface during manufacture.

Rolled-in slugs A foreign metallic body rolled into the metal surface, usually not fused.

Seam Crevice in rolled metal which has been more or less closed by rolling or other work, but has not been fused into sound metal.

Hard Spot An area in the pipe with a hardness level considerably higher than that of the surrounding metal, usually due to localized quenching.

Crack A stress-induced separation of metal which, without other influence, is insufficient in extent to cause rupture of the material.

Incomplete Fusion Lack of complete coalescence of some portion of the metal in a weld joint.

Incomplete Penetration A condition where the weld metal does not continue through the full thickness of the joint. (The first weld pass or root pass.)

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Undercut Undercutting on submerged-arc-welded pipe is the reduction in the thickness of the pipe wall adjacent to the weld where it is fused to the surface of the pipe.

Weld Area Crack A crack that occurs in the weld deposit, the fusion line or the heat-affected zone.

Upturned Fiber Imperfection Metal separations, resulting from imperfections at the edge of the plate or skelp, parallel to the surface, which turn toward the ID or OD pipe surface when edges are upset during welding.

Penetrator A localized spot of incomplete fusion.

Cold Weld A metallurgically inexact term generally indicating a lack of adequate weld bonding strength of the abutting edges, due to insufficient heat and/or pressure. A cold weld may or may not have separation in the weld line. Other more-definitive terms should be used whenever possible.

DEFECTS RESULTING FROM EXTERNAL OR INTERNAL DEGENERATION OF THE PIPE Selective Corrosion Preferential corrosion in the fusion line of an ERW or FW longitudinal seam.

Hydrogen Stress Cracking Environmentally stimulated cracking of the weld metal or heat-affected zone of the longitudinal seam.

Blister A raised spot on the surface of pipe caused by expansion of gas in a cavity within the pipe wall.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

Generalized Corrosion Reduction of the wall thickness of the pipe over a wide area of the pipe surface caused by the electrochemical environment.

Pitting Corrosion Isolated or connected pits in the pipe wall caused by the electrochemical environment.

Hydrogen Stress Cracking (in a hard spot) Environmentally stimulated cracking of an abnormally hard spot in the body of the pipe.

Stress Corrosion Cracking Crack-like defects, usually occurring in clusters which arise because of particular combinations of stress and electrochemical environments.

DEFECTS CAUSED BY OUTSIDE FORCES Dent A local change in surface contour caused by mechanical impact, but not accompanied by loss of metal.

Gouge Elongated grooves or cavities caused by mechanical removal of metal.

Gouge and Dent Combination of the above.

GIRTH WELD DEFECTS Incomplete Fusion Lack of complete coalescence of some portion of the metal in a weld joint.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Incomplete Penetration A condition where the weld metal does not continue through the full thickness of the joint.

Weld Area Cracks A crack that occurs in the weld deposit, the fusion line, or the heat affected zone.

Undercut The reduction in thickness of the pipe wall adjacent to the weld where it is fused to the surface of the pipe.

OTHER DEFECTS Arc Burn Localized point of surface melting caused by arching between the electrode or ground and pipe surface.

Buckle Wrinkle bend.

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

APPENDIX C - PIPE REPAIR OPTIONS This matrix provides repair options for a variety of defects. See Appendix B of this procedure for defect descriptions. The Asset Integrity Team (Pipeline Integrity Technologist), Technical Services or other appropriate subject matter expert assistance may also be needed to select and develop the best repair technique.

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PERMANENT PIPE REPAIR OPTIONS The purpose of this matrix is to assist in the selection of repair options. It does not designate that every defect must be repaired and/or replaced. See Appendix B of this procedure for defect descriptions. Repair Manufacturing Defects Method In Seam Weld

Seamless Pipe or In Pipe Body Only Lap, Hard spot Pit, exceeding Rc>35 Seam, and 2” in extent Crack or more Rolled-in-slug

Undercut, Incomplete fusion., Incomplete penetration Crack, cold weld, upturned fiber Non Leaking defects Full Encirclement Sleeves (welded) (MIP-403) Pipe Replacement (MIP-404)

Selective seam corrosion

General corrosion

Pitting Corrosion

Stress corrosion cracking

Hydrogen stress cracking in hard spot

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X

X

X

X

X

X

X

X

X

X

Removal by Hot Tap

X

Mechanical Sleeves (non welded) (MIP-403) Composite Sleeve Repair (MIP-403)

Repair Method

Non Leaking Defects Full Encirclement Sleeves (welded) (MIP-403) Pipe Replacement (MIP-404)

X

X

X (Note 1)

X (Note 1)

Defects Caused By: Outside Forces

X

X X (Note 1)

Rupture

Girth Weld Defects

In Seam or Other Weld Plain dent, gouge, or gouge-in-dent

Plain dent

In Body of Pipe Gouge only (>12.5%of nom. w.t.)

Gouge in dent

Rupture

Undercut, Incomplete fusion, Incomplete penetration, crack

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X (Note 2)

X

X

X

X

X

X

X

X

X

X

X

X

X

X (Plain dents only – Note 1)

X (Note 1)

Removal by Hot Tap Mechanical Sleeves (non welded) (MIP-403) Composite Sleeve Repair (MIP-403)

Environmentally Caused Defects

Note 1: See Section 5.10 for limitations on installations

Note 2: Wall thickness must be .188 min.

MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

APPENDIX D – FIBERGLASS COMPOSITE REPAIR DETAILS 1.0

CLOCK SPRING DETAILS

1.1

Girth Weld Repair

These guidelines are included to provide some awareness on the application of the Clock Spring wrap. For the latest and most accurate instructions see the Clock Spring application procedures. 1.1.1

Clock Spring® composite repair system can be used to reinforce corrosion or other blunt defects that affect the girth weld zone.

1.1.2

Clock Spring® provides hoop reinforcement for pipe damaged by corrosion or other blunt defects by wrapping tightly around the pipe and sharing the hoop load. The cap of a girth weld restricts the Clock Spring® contact with the pipe. Defects in the weld zone can be repaired by bridging the weld cap with an additional Clock Spring® unit. Clock Springs are installed on either side of the weld; the space between the units is filled with high compressive strength filler and a third unit installed over the filled gap.

1.1.3

The following technique will provide structural reinforcement for external corrosion, or other blunt defects associated with the girth weld zone. The three steps to the process are: •

Application of Clock Spring® on both sides of the weld.

•

Molding the area between the Clock Spring® units (over the weld bead) with filler material using a single wrap mold.

•

Application of the bridging unit.

1.1.4

Only certified installers may apply Clock Spring®.

1.1.5

The pipeline operator must inspect the weld zone to ensure that it is free of cracks.

1.1.6

Defect shall not exceed the following •

50% pipe wall loss

•

30% of the pipe circumference

1.1.7

The following additional material is required. Filler kits, single-wrap mold, parting film, tie-down straps, 100-grit sandpaper.

1.1.8

Installation Page 403-D1

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

1.2

•

Install a Clock Spring® unit on each side of the girth weld. (See Figure 1) (Optional: Six-inch (150 mm) wide Clock Spring® may be used.)

•

Remove all extruded adhesive material from the area of the girth weld.

•

Allow adhesive to cure and remove the securing filament tape nearest the girth weld.

•

Apply filler material to the area between the Clock Spring® units (over the weld bead). Install the parting film and the single-wrap Clock Spring mold. Tighten the mold using the tie-down straps. (See Figure 2)

•

Remove all extruded filler material.

•

Allow the filler to harden (approximately 1-1/2 hours). Cure time will be affected by temperature.

•

Remove mold, lightly abrade filler and the exterior of the installed Clock Springs, and wipe abraded area.

•

Apply filler material as required to all voids, center and install the “Bridging” Clock Spring® unit over the girth weld in accordance with standard Clock Spring® repair procedures. (See Figure 3)

Bend Repair

1.2.1

Clock Spring® provides hoop reinforcement for pipe damaged by corrosion or other blunt defects by wrapping tightly around the pipe and sharing the hoop load. Defects in bends require special consideration to ensure that the following design requirements are met (Figure 1a, b, c).

1.2.2

Only certified installers may apply Clock Spring®.

1.2.3

Install Clock Spring® units in accordance with standard Clock Spring® repair procedures.

1.2.4

Installation •

The repair area shall have the installed Clock Spring® units extend a minimum of 2 inches (51 mm) beyond both ends of the defect.

•

The gap between the Clock Spring® and the intrados of the bend shall not exceed 0.187 inches (4.8 mm).

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

Chevron Pipe Line Company

•

The gap between adjacent Clock Spring® units on the extrados of the bend shall not exceed 0.5 inches (12.7 mm).

•

The width of each Clock Spring® unit shall not be less than 2.5 inches (63.5 mm).

•

Start the installation of Clock Spring® units from the middle of the defect moving outwards

•

In addition to applying filler material to all cavities and tented areas, ensure that filler is applied to both the intrados and extrados area of the pipe contacting the Clock Spring® unit.

Figures 1a, b, c Bend Repairs The design of the bend repair requires specific information about the bend. In addition to pipe grade, diameter, wall thickness, class location, defect length, defect width and defect depth; provide:

(S1 and S2) Or (C and H)

Figure 2 Page 403-D3 © COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

1.3

Dent Repair

1.3.1

The following procedure provides the generic approach to reinforcing dented pipe sections. Reinforcing dented pipe reduces cyclical loading that can lead to time dependent failure. 1.3.2 The repair is limited to smooth dents caused by inadvertent pipe contact with machinery or objects in the ditch or backfill. Stress concentrators in the dent must be removed in accordance with applicable codes and the dent area inspected for surface cracking.

Figure 1

Figure 2

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MAINTENANCE AND INSPECTION PROCEDURES Chevron Pipe Line Company

Pipe Repair

Figure 3

Figure 4

Figure 5 Page 403-D5 © COPYRIGHT 2005 Chevron Pipe Line Company. All Rights Reserved

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MAINTENANCE AND INSPECTION PROCEDURES Pipe Repair

1.4

Chevron Pipe Line Company

Marking ClockSpring Repair Locations

1.4.1

Clock Spring® repair material is not magnetic and cannot be detected with an MFL smart pig inspection. This procedure is to be used when installing Clock Spring® to be able to detect the repair location. Having the Clock Spring® identified in the tool data provides definitive information about previous repairs and serves to identify locations that may be used to verify tool performance.

1.4.2

Detailed measurements of the defect should be acquired before installation of the Clock Spring®. This information should then be filed for future reference. On subsequent inspections, this information can confirm the performance of the inspection tool or be used to help calibrate the inspection tool for better data analysis.

1.4.3

The procedure outlined is only effective for Magnetic Flux Leakage (MFL) inspection tools. • Measure the external defect and record results for future reference. • Install the Clock Spring® using standard installation procedures. • Wrap five (5) layers of steel banding material on top of the Clock Spring® at each end. (See Figure 1.) The banding material is standard 1.25” x .031” steel strap used for material shipping. (Groves Industrial Supply #14031) • Coat and back-fill.

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