Pipeline Operating and Maintenance Procedures

Pipeline Operating and Pipeline Operating and Maintenance ProceduresMaintenance Procedures

Introduction

• Developed based on code provision, company experience, and knowledge of facilities and operating condition

• Location Class should be determined upon initiating gas service

Basic Requirements

• Written plan covering operating and maintenance procedures

• Written emergency plan covering facilities failure

• Operating and maintaining its facilities in conformance with those plans

• Modifying the plans periodically

• Employee training about operating and maintaining

Essential Features of the Operating and Maintenance Plan

• Detailed plans and instruction for normal operation and repair

• Plans for the greatest hazard conditions

• Provisions for periodic inspections along the route of existing steel pipelines or mains to consider the possibility of location class changes

Essential Features of the Emergency Plan

• System for receiving, identifying, and classifying emergencies

• Indicating the responsibility for instructing employees and for training employees in the execution of the procedures

• Indicating the responsibility in updating the plan

• Establishing a plan to handle all calls that concerns emergency

• Establishing a plan for response to a notice of emergency

• Controlling emergency situations, including the action to be taken by the first employee arriving at the scene

• Dissemination of information to the public

• The safe restoration of service to all facilities affected by the emergency

• Reporting and documenting the emergency

Training Program

• Provided to prepare the employee response in emergency condition

• The employee should mastering the emergency procedures and action in handling the situation

• The program established and maintained on a continuing basis with provision for updating the procedures

Educational Program

• Established to enable the public to recognize and report the gas emergency

• Operator of each section should communicate their program to the general public

• The programs in the same area should be coordinated to avoid inconsistency

Prevention of Accidental Ignition

• Source of ignition should be removed and adequate fire extinguisher should be provided

• Provide signs, flagmen or guard to warn about the hazardous area

• Accidental ignition by electric arcing can be prevented by connecting the cables to each side of any piping that is to be parted or joined

• Welding process and cutting process using torch should be done by checking the combustible gas mixture

PIPELINE MAINTENANCE Periodic Surveillance of Pipelines

Taken when unusual operating and maintenance conditions occur, such as failures and leakage. If not satisfying, a planned program shall be initiated to abandon, replace or recondition and proof test

Pipeline Patrolling

to observe surface conditions on and adjacent to each pipeline right-of way, indications of leaks, construction activity and any other factor

affecting the safety and operation

Leakage Surveys

Types of surveys shall be effective for determining if potentially hazardous leakage exists. The extent and frequency are determined by the operating pressure, piping age, and class location

PIPELINE MAINTENANCE

(Continued)

Maintenance of Cover at Road Crossings

Maintenance can be done by providing barriers, culverts, concrete

pads, casing, or lowering the line

Repair procedures for steel pipelines operating at hoop stress levels at or above 40% Fy

- Temporary measure should be employed to protect the property and the public.

- Using welded patch as a repair method is prohibited

Permanent Field Repairs of Injurious Gouges, Grooves, and Dents

• Removed or reinforce or reduced the operating pressure

• If feasible, the pipeline is taken out of service and replacing the injurious with a better one

• If the pipeline can’t be out of service, following alternative repairs can be done:

- Full encirclement welded split sleeve with or without circumferential fillet welds

- Hot tapping or grinding

• If a dent is repaired with a sleeve and circumferential fillet weld are not made, the dent shall be filled by hardenable filler

Permanent Field Repairs of Welds Having Injurious Defects

• Reduce the operating pressure to a pressure that will not produce a stress in excess of 20% yield stress

• Full encirclement welded split sleeve using circumferential fillet welds

• Injurious occurs by electric resistance weld seam can be repaired by full encirclement welded split sleeve with pressurized sleeve by hot tapping the pipeline under the sleeve

Permanent Field Repairs of Leaks and non-leaking Corroded Areas

• If feasible, the pipeline is taken out of service and replacing the injurious with a better one

• If not feasible to taken out of service, full encirclement welded split sleeve using circumferential fillet welds is done

• For corroded area smaller than 40.000 psi, the leak can be repaired by using a steel plate patch with rounded corner

• Small corroded area may be repaired by filling them with deposited metal from low-hydrogen electrodes

Pipeline leak records

Covering all leaks discovered and repairs made.

Pipeline markers

• installed to indicated the presence of pipeline at road, highway, railroad and stream crossings.

• Easy to read and not obscured

• the signs must include the name of gas transported, company, and telephone number

Abandoning of transmission facilities

• Abandoned facilities must be disconnected from all sources and supplies of gas

• Facilities to be abandoned in place shall be purged of gas with an inert

Repositioning a pipeline in service

Factors to be considered:

• Deflection, diameter, wall thickness, and grade of pipe

• Pipeline pressure

• Type of girth welds

• Test and operating history

• Presence of defects

• Existing curvature

• Bends, valves and fitting

• Terrain and soil condition

• Personnel safety consideration

• Additional stresses

DISTRIBUTION PIPING MAINTENANCE

Patrolling

Leakage Surveys

• Surface and subsurface gas detection surveys

• Vegetation surveys

• Pressure drop, bubble leakage and ultrasonic leakage tests

Leakage investigation and action

• Leakage Classification and Repair

• Investigation of reports from outside

• Odor or indicators from foreign sources

• Follow up Inspection


(Continued)

Requirements for Abandoning, Disconnecting, and Reinstating Distribution Facilities

• Abandoning of distribution facilities

• Temporarily disconnected service

• Test requirements for reinstating abandoned facilities and temporarily disconnected service line

Plastic pipe maintenance

• Pinching and reopening of thermoplastic pipe and tubing for pressure control

• Repair of plastic pipe or tubing


(Continued)

Piping maintenance records

• the condition of the surface of bare pipe if corroded

• condition of pipe surface and of the protective coating

• any damaged protective coating

• any repair made

• thermal effect


(Continued)

Cast iron pipe maintenance

• For operating pressure more than 25 psig, the pipe must be sealed with a mechanical leak clamp

• For operating pressure less than 25 psig, the pipe must be sealed by means other than caulking

• Inspection to check the existing graphitization

• Provide permanent protection for buried cast iron pipeline

MISCELLANEOUS FACILITIES MAINTENANCE

Compressor station maintenance

• Compressors and prime movers

• Inspection and testing of relief valves

• repairs to compressors station piping

• Isolation of equipment for maintenance

• storage of combustible materials

• maintenance and testing of gas detection and alarm systems


(continued)

Procedures for maintaining pipe-type and bottle-type holders in safe operating condition

• detection of external corrosion

• periodic sampling and testing gas that may cause internal corrosion

• pressure control and pressure limiting must be inspected


(continued)

Maintenance of pressure limiting and pressure regulating stations

• Visual Inspection

• The case of malfunction must be determined

• At least once a year, a review shall be made to ensure that the facilities working properly

• Inspection on valves should be taken

• Gas pressure must be monitored


(continued)

Valve Maintenance

• Routine valve maintenance

• Distribution System valves

• Service line valves

• Valve records

• Prevention of accidental operation

Vault Maintenance

Vault shall be inspected to determine its condition. Vault that personnel enter must be checked for combustible gas.

LOCATION CLASS

TABLE 854.1C

LOCATION CLASS

Changes in Location Classification

• Steel pipeline operating in excess of 40% SMYS must be monitored if additional buildings intended for human occupancy have been constructed

• The change should be made by judging items such as operating stress levels, frequency of patrolling, and cathodic

protection requirement

• If the number of buildings near the upper limit of location class in table, shall complete study in 6 months to determine:

- Design, construction, and testing procedures

- Physical condition of pipeline

- Operating and maintenance history of pipeline

- Maximum operating pressure and hoop stress

- Actual area affected

Changes in Location Classification (Continued)

If maximum allowable operating pressure (MAOP) of pipeline is not commensurate with existing locations 2, 3 or 4, the MAOP shall be revised within 18 months following completion study of section involved in less than 2 hours, MAOP shall be reduced thus not exceed that allowed in table

Concentration of People in Location Class 1 and 2

• Possible failure must be considered if the facilities were built near an existing steel pipeline in location classes 1 and 2

• Pipelines near places of public assembly shall has a maximum allowable stress not exceeding 50% of specified minimum yield strength

• Level of safety that the segment is hydrostatically retested for at least 2 hr to a minimum stress level of:

- 100% of SMYS if the pipeline is operating over 60% and up to 72% of SMYS

- 90% of SMYS if the pipeline is operating over 50% and up to 60% of SMYS

• Patrols and leakage surveys are conducted at an intervals

PIPELINE SERVICE CONVERSIONS

General

Provide the requirements to allow an operator of a steel pipeline previously used for service not covered by this code to qualify that pipeline for the service under this code

Historical Records Study

• pipeline design, inspection and testing

• Operating and maintenance data including leak records, inspections, failure, cathodic protection, and internal

corrosion control practices

• the age of the pipeline and the length of service time

Requirements for conversion to gas service

Conversion Procedure

Records of the conversion


(continued) Requirements for conversion to gas service

• Historical records

• Inspection on all above-ground segments of the pipeline

• Operating stress level study

• Inspections on appropriate sections of underground piping

• Replacements, repairs or alterations

• Strength test

• Leak test

• Cathodic protection




(continued)


Prepare a written procedure outlining the steps to be followed during the study and conversion of the pipeline system


Maintain for the life of the pipeline a record of the studies, inspections, tests, repairs, replacements, and alteration made in connection with conversion of the existing steel pipeline to gas service under this code

Pipeline Operating and Maintenance Procedures

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