pipeline maintenance

AS 2885.3—2001

AS 2885.3

Australian Standard™ Pipelines—Gas and liquid petroleum Part 3: Operation and maintenance

This Australian Standard was prepared by Committee ME-038, Petroleum Pipelines. It was approved on behalf of the Council of Standards Australia on 27 July 2001 and published on 6 August 2001.

The following interests are represented on Committee ME-038: Australian Corrosion Association Australian Gas Association Australian Institute of Petroleum Australian Petroleum Production and Exploration Association Australian Pipeline Industry Association Bureau of Steel Manufacturers of Australia Cooperative Research Centre for Materials, Welding and Joining Department of Labour New Zealand Department of Minerals and Energy WA Department of Mines and Energy (NT) Department of Natural Resources and Environment (Victoria) Department of Natural Resources and Mines (Qld) Gas Association of New Zealand Ministry of Energy and Utilities NSW Primary Industries and Resources SA Welding Technology Institute of Australia

Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Detailed information about Standards can be found by visiting the Standards Australia web site at www.standards.com.au and looking up the relevant Standard in the on-line catalogue. Alternatively, the printed Catalogue provides information current at 1 January each year, and the monthly magazine, The Australian Standard, has a full listing of revisions and amendments published each month. We also welcome suggestions for improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at [email protected], or write to the Chief Executive, Standards Australia International Ltd, GPO Box 5420, Sydney, NSW 2001.

This Standard was issued in draft form for comment as DR 00338.

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AS 2885.3—2001

Australian Standard™ Pipelines—Gas and liquid petroleum Part 3: Operation and maintenance

Originated in part as AS CB28—1972. Previous edition AS 2885.3—1997. Second edition 2001.

COPYRIGHT © Standards Australia International All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Published by Standards Australia International Ltd GPO Box 5420, Sydney, NSW 2001, Australia ISBN 0 7337 4084 7

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PREFACE This Standard was prepared by the joint Standards Australia/Standards New Zealand Committee ME-038, Petroleum Pipelines, to supersede AS 2885.3 — 1997. This Standard is the result of a consensus among Australian and New Zealand representatives on the Joint Committee to produce it as an Australian Standard. This Standard has been reviewed and revised to correlate with the requirements of Safety Case. Due to significant changes in the industry and the regulatory environment, the Standard has been restructured, and is based on Pipeline Integrity Management philosophy. Changes have been made to the Standard to enable it to be viewed as a stand-alone document whilst retaining and strengthening the references to AS 2885.1 and AS 2885.2. The readability of the document has been improved by drawing together like requirements into common sections, by improving the cross-references and by applying a consistent style to the structure and wording. The most important changes include the following: (a)

The addition of Pipeline Integrity Management principles.

(b)

A major review of the Operating Condition Changes section.

(c)

The inclusion of a records management process.

(d)

Responsibilities of the operating authority have been clarified.

(e)

Risk Assessment process has been further integrated.

(f)

Contents of Safety and Operating Plan have been clarified.

(g)

Approval requirements have been identified and listed in Appendix C.

(h)

The development of a threat mitigation section.

(i)

A revision of the Cathodic Protection section.

(j)

The introduction of a Safety and Environment section.

(k)

The inclusion of signage maintenance

(l)

Coverage of SCADA maintenance.

The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the appendix to which they apply. A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance.

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AS 2885.3—2001

CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE .........................................................................................................................5 1.2 BASIS OF STANDARD ..............................................................................................5 1.3 APPLICATION............................................................................................................5 1.4 RISK MANAGEMENT ...............................................................................................6 1.5 REFERENCED DOCUMENTS ...................................................................................6 1.6 DEFINITIONS ............................................................................................................6 SECTION 2 PREPARATION FOR OPERATION 2.1 GENERAL ...................................................................................................................9 2.2 PLANS AND PROCEDURES ....................................................................................9 2.3 RESPONSIBILITIES FOR PERSONNEL ...................................................................9 2.4 READINESS FOR OPERATION ................................................................................9 2.5 DELAYED COMMENCEMENT OF OPERATION.................................................. 10 2.6 PURGING AND FILLING A PIPELINE—PROCEDURES...................................... 10 SECTION 3 PIPELINE INTEGRITY MANAGEMENT 3.1 BASIS OF SECTION................................................................................................. 13 3.2 GENERAL ................................................................................................................ 13 3.3 PIPELINE STRUCTURAL INTEGRITY ................................................................. 13 3.4 THREAT MITIGATION............................................................................................ 14 3.5 SAFETY AND ENVIRONMENT.............................................................................. 15 SECTION 4 PLANS AND PROCEDURES 4.1 GENERAL ................................................................................................................. 16 4.2 SAFETY AND OPERATING PLAN......................................................................... 16 4.3 EMERGENCY PLANS.............................................................................................. 17 4.4 PROCEDURES.......................................................................................................... 19 SECTION 5 PIPELINE STRUCTURAL INTEGRITY 5.1 GENERAL ................................................................................................................. 20 5.2 OPERATING AND DESIGN CONDITIONS ............................................................ 20 5.3 PIPELINE INSPECTION AND ASSESSMENT ....................................................... 20 5.4 PIPE WALL DEFECT ASSESSMENT ..................................................................... 21 5.5 COATINGS ............................................................................................................... 24 5.6 CATHODIC PROTECTION ..................................................................................... 25 5.7 INTERNAL SURFACES ........................................................................................... 26 5.8 STATIONS ................................................................................................................ 26 5.9 ANCILLIARY EQUIPMENT .................................................................................... 27 SECTION 6 THREAT MITIGATION 6.1 GENERAL ................................................................................................................ 29 6.2 PIPELINE SURVEILLANCE .................................................................................... 29 6.3 PIPELINE MARKING............................................................................................... 30 6.4 EXTERNAL INTERFERENCE PREVENTION ....................................................... 31 6.5 CONTROLLING ACTIVITIES NEAR PIPELINES.................................................. 32

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Page SECTION 7 SAFETY AND ENVIROMENT 7.1 GENERAL ................................................................................................................. 35 7.2 EMERGENCY RESPONSE....................................................................................... 35 7.3 VENTING PROCEDURES........................................................................................ 35 7.4 PROCEDURES TO FREE PIPELINES OF HYDROCARBONS .............................. 36 7.5 COMMUNICATIONS SYSTEMS............................................................................. 37 7.6 SCADA...................................................................................................................... 37 7.7 PIPELINE FACILITY CONTROL ............................................................................ 38 7.8 NOISE ABATEMENT............................................................................................... 38 7.9 ENVIRONMENT....................................................................................................... 38 7.10 ELECTRICAL SAFETY ON METALLIC PIPELINES............................................. 38 SECTION 8 OPERATING CONDITION CHANGES 8.1 DESIGN CONDITION CHANGES ........................................................................... 39 8.2 PRESSURE TESTING OF DESIGN CONDITION CHANGES ................................ 40 8.3 PIPELINE MODIFICATIONS................................................................................... 40 8.4 REVIEW OF PRESSURE-CONTROL AND OVER-PRESSURE PROTECTION SYSTEMS.................................................................................................................. 40 8.5 REVIEW OF DESIGN LIFE...................................................................................... 40 8.6 REVIEW OF MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP) ...... 41 8.7 REVIEW OF LOCATION CLASSES........................................................................ 41 8.8 REVIEW OF RISK ASSESSMENT .......................................................................... 41 8.9 OPERATION OF A SUSPENDED PIPELINE .......................................................... 41 8.10 ABANDONING A PIPELINE ................................................................................... 42 8.11 ABANDONMENT OF ABOVE-GROUND PIPELINES........................................... 42 8.12 ADDITIONAL REQUIREMENTS FOR ABANDONMENT .................................... 42 8.13 ABANDONMENT RECORDS.................................................................................. 43 SECTION 9 PIPELINE REPAIRS 9.1 GENERAL ................................................................................................................. 45 9.2 SUPERVISION.......................................................................................................... 45 9.3 COMMUNICATION AND CONTROL..................................................................... 45 9.4 WORKING ON PIPELINES...................................................................................... 45 9.5 REPAIR STRATEGY ................................................................................................ 48 9.6 WELDING ONTO AN IN-SERVICE PIPELINE ...................................................... 49 9.7 HOT-TAPPING OPERATIONS ................................................................................ 51 SECTION 10 RECORDS 10.1 GENERAL ................................................................................................................. 52 10.2 DESIGN, CONSTRUCTION AND COMMISSIONING RECORDS ........................ 52 10.3 OPERATION AND MAINTENANCE RECORDS ................................................... 53 10.4 ABANDOMENT RECORDS..................................................................................... 53 APPENDICES A LIST OF REFERENCED DOCUMENTS.................................................................. 54 B DOCUMENT HIERARCHY...................................................................................... 56 C LIST OF APPROVAL REQUIREMENTS................................................................. 57 D ASSESSMENT OF A CORRODED PIPELINE ........................................................ 59 E TYPICAL PIPELINE MARKERS ............................................................................. 70

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AS 2885.3—2001

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STANDARDS AUSTRALIA Australian Standard Pipelines—Gas and liquid petroleum Part 3: Operation and maintenance

S E CT I ON

1

S COP E

AND

G E N ERAL

1.1 SCOPE This Standard specifies the minimum requirements for the operation and maintenance of pipelines complying with AS 2885.1 and AS 2885.2. 1.2 BASIS OF STANDARD The purpose of the AS 2885 series of Standards is detailed in Part 1. The basis of this part of the AS 2885 series of Standards is to provide important principles, practices and practical guidelines for use by competent persons and organizations involved in the operation and maintenance of high-pressure petroleum pipelines. The fundamental principles on which this Part is based are the following: (a)

Important matters relating to safety, engineering design, materials, testing and inspection to be reviewed and approved by a responsible entity, referred to as the operating authority. The responsible entity to be defined in each case.

(b)

Operation and maintenance practices to be implemented to provide for continued monitoring and safe operation of the pipeline.

(c)

Where the Standard does not provide detailed requirements appropriate to a specific item, the principles and guidelines set out in the Standard to be the basis on which an engineering assessment is made. Specific requirements of the Standard do not replace the need for appropriate experience and engineering judgement.

1.3 APPLICATION The requirements of this Standard apply to the operation and maintenance of pipelines designed in accordance with AS 2885.1. This Standard is not intended to be applied retrospectively to existing pipelines that have not been modified unless the following requirements are met: (a)

The requirements of this Standard shall apply to the operation and maintenance of existing pipelines designed and built under those Standards superseded by this Standard, where such pipelines are modified to operate under the conditions within the scope of this Standard.

(b)

Operating authorities, which operate and maintain pipelines that are not designed and constructed in accordance with AS 2885.1, and where it is not feasible to physically modify the pipeline, may apply this Standard provided the areas of non-compliance with AS 2885.1 are documented and are subject to risk assessment. Any actions required to mitigate risk shall be approved in the safety and operating plan.

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1.4 RISK MANAGEMENT Risk management during operation and maintenance shall be addressed in accordance with the requirements of AS 2885.1. 1.5 REFERENCED DOCUMENTS The documents referred to in this Standard are listed in Appendix A. 1.6 DEFINITIONS For the purpose of this Standard, the definitions given in AS 1929, AS 2812, AS/NZS 2832.1 and those below apply. 1.6.1 Approved and approval Approved by the operating authority, and includes obtaining the approval of the relevant regulatory authority where this is legally required. NOTE: Approval requires a conscious act and is given in writing.

1.6.2 Casing A conduit through which a pipeline passes, to protect the pipeline from excessive external loads or to facilitate the installation or removal of that section of the pipeline. 1.6.3 Collapse A permanent cross-sectional change to the shape of a pipe (normally caused by instability, resulting from combinations of bending, axial loads and external pressure). 1.6.4 Component Any part of a pipeline other than the pipe. 1.6.5 Construction Activities required to fabricate, construct and test a pipeline and associated infrastructure, and to restore the route of a pipeline. 1.6.6 Defect A discontinuity or imperfection of sufficient magnitude to warrant rejection on the basis of the requirements of this Standard. 1.6.7 Dent A depression in the external surface of the pipe caused by mechanical damage, which produces a visible irregularity in the curvature of the pipe wall without reducing the wall thickness (as opposed to a scratch or gouge, which reduces the pipe wall thickness) 1.6.8 Diameter The outside diameter nominated in the material order. 1.6.9 Fitting A component, including the associated flanges, bolts and gaskets used to join pipes, to change the direction or diameter of a pipeline, to provide a branch, or to terminate a pipeline. 1.6.10 Fluid Any liquid, vapour, gas or mixture of any of these. 1.6.11 Gas Any hydrocarbon gas or mixture of gases, possibly in combination with liquid petroleum condensates or water. © Standards Australia

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1.6.12 High vapour pressure liquid (HVPL) A liquid or dense phase fluid which releases significant quantities of vapour when its pressure is reduced from pipeline pressure to atmospheric, e.g., LP gas. 1.6.13 Hoop stress Circumferential stress in a cylindrical pressure-containing component, arising from internal pressure. 1.6.14 Hot tap A connection made to an operating pipeline containing hydrocarbon fluid. 1.6.15 Inert gas A non-reactive and non-toxic gas such as argon, helium or nitrogen. 1.6.16 Inspector A person appointed by the operating authority to carry out inspections required by this Standard. 1.6.17 Leak test A pressure test that determines whether a pipeline is free from leaks, which is performed in accordance with AS 1978 1.6.18 Location class An area classified according to its general geographical and demographical characteristics, as defined in AS 2885.1. 1.6.19 Maximum allowable operating pressure (MAOP) The maximum pressure at which a pipeline may be operated (see Clause 5.2 (b)). 1.6.20 May Indicates the existence of an option. 1.6.21 Operating authority The organization responsible for the design, construction, testing, inspection, operation and maintenance of pipelines and facilities within the scope of this Standard. 1.6.22 Petroleum Any naturally occurring hydrocarbon or mixture of hydrocarbons in a gaseous or liquid state, which may contain hydrogen sulfide, nitrogen, helium, carbon dioxide and trace quantities of other materials. 1.6.23 Pig A device that is propelled inside a pipeline by applied pressure. 1.6.24 Pig trap (scraper trap) A fabricated component to enable a pig to be inserted into or removed from an operating pipeline. 1.6.25 Piping An assembly of pipes, valves and fittings connecting auxiliary and ancillary components associated with a pipeline. 1.6.26 Pre-tested The condition of a pipe or a pressure-containing component that has been subjected to a pressure test in accordance with this Standard before being installed in a pipeline. www.standards.com.au

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1.6.27 Protection measures (a)

Procedural— measures for protection of a pipeline, to minimize the occurrence of activities by third parties, which could damage a pipeline.

(b)

Physical—measures for protection of a pipeline that prevent external interference from causing sufficient damage to a pipeline to cause penetration of the pipe wall, rupture the pipeline or reduce the pressure strength of the pipeline below the maximum allowable operating pressure.

1.6.28 Regulatory authority An authority with legislative powers relating to petroleum pipelines. 1.6.29 Risk assessment A systematic identification and evaluation of threats to personnel and pipelines to facilitate appropriate management of these threats in accordance with the methodology prescribed in AS 2885.1. 1.6.30 Shall Indicates that a statement is mandatory. 1.6.31 Should Indicates a recommendation. 1.6.32 Specified minimum yield stress (SMYS) The minimum yield stress for a pipe material that is specified in the manufacturing standard with which the pipe or fittings used in the pipeline complies. 1.6.33 Station pipe work Those parts of a pipeline within a station (e.g., pump station, compressor station, metering station) which begin and end where the pipe material specification changes to that for the mainline pipe work. 1.6.34 Strength test A pressure test that confirms that the pipeline has sufficient strength to allow it to be operated at MAOP. 1.6.35 Telescoped pipeline A pipeline that is made up of more than one diameter or MAOP, tested as a single unit. 1.6.36 Wall thickness, nominal The thickness of the wall of a pipe that is nominated for its manufacture, ignoring the manufacturing tolerance provided in the nominated Standard to which the pipe is manufactured. (Quantity symbol δN.)

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S E CT I ON

2

P REP AR AT I ON

FOR

OP E RAT I ON

2.1 GENERAL Preparations for operation shall be deemed complete when the plans and procedures set out in this Section have been implemented. With the preparation completed and with approval given to start operation, the filling of the pipeline can occur and the pipeline can then be put into operation. 2.2 PLANS AND PROCEDURES The operating authority shall ensure that the following plans and procedures have been prepared and approved as appropriate, and that personnel have been properly trained in their application: (a)

A safety and operating plan including an emergency plan (see Sections 4 and 7).

(b)

Operating, maintenance and repair procedures.

(c)

An environmental code of practice to deal with possible pipeline leaks and ruptures.

2.3 RESPONSIBILITIES FOR PERSONNEL Personnel responsible for the operation and maintenance of the pipeline shall, as applicable to their position, be— (a)

adequately trained and experienced in all aspects of the equipment in their control;

(b)

adequately briefed in the requirements of the actions defined in the risk assessment;

(c)

aware of properties of the fluid, including its hazard level in accordance with AS 4343;

(d)

capable of ensuring the safe disposal of any accidentally discharged fluid; and

(e)

capable of arranging for damaged pipelines to be repaired.

2.4 READINESS FOR OPERATION Pipelines shall not be considered ready to commence or recommence operation unless, as a minimum, the following check list has been completed: (a)

The pipeline complies with the requirements of all relevant parts of AS 2885.1.

(b)

The hydrostatic strength and leak test requirements have been achieved and documented.

(c)

The MAOP has been established.

(d)

The welds of tie-ins to existing facilities, which have not been subjected to testing in accordance with Item (b), have been inspected by an approved non-destructive examination method, and comply with AS 2885.2.

(e)

Components have been tested for satisfactory operation. Where impractical, other appropriate inspection shall be carried out.

(f)

Operating, maintenance and emergency personnel have been trained.

(g)

The pipeline is cathodically protected as required by AS 2885.1.

(h)

Threat mitigation measures have been implemented in accordance with Section 3.4.

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NOTES: 1 Additional site-specific aspects may need to be evaluated prior to commencement of operation. 2 Initial operation may be approved before completion of the field work, provided that the incomplete work does not directly affect the safety of the pipeline, the public, or the operating personnel. 3 For a list of plans and procedures that this Standard requires to be approved, see Appendix C.

2.5 DELAYED COMMENCEMENT OF OPERATION Where a pipeline is to be placed in operation with a time delay, it shall meet the requirements of Clause 2.4. If the hydrostatic test fluid is allowed to remain in the pipeline, the test fluid shall either be dosed with a corrosion inhibitor or the pipeline filled with a fluid that inhibits corrosion, unless it can be demonstrated that such measures are not warranted. Where the test fluid is removed, the pipeline shall be dried or purged, or both, with inert gas to produce a moisture level that will not promote corrosion during the delay period. Where the pipeline is left filled with a fluid, precautions shall be taken to ensure that no damage is caused by overpressure due, for example, to thermal expansion effects. During the period between the hydrostatic test and the initial operation, the pipeline integrity shall be maintained in accordance with this Standard. Corrective action shall be taken when an inspection reveals that unacceptable corrosion is occurring. 2.6 PURGING AND FILLING A PIPELINE — PROCEDURES 2.6.1 General To bring a pipeline into service, the operating authority shall ensure that— (a)

a pipeline is purged and filled in a safe manner;

(b)

work is undertaken on a pipeline only when all relevant aspects of this Standard have been complied with;

(c)

an approved procedure is developed specific to the pipeline and the nature of the fluid being purged, filled or commissioned; and;

(d)

the approved procedure is implemented during purging and filling or commissioning.

The procedure shall address the following requirements: (i)

The appropriate number, experience, training and induction of personnel involved in the procedure.

(ii)

The level and control of the filling rate.

(iii) Controlling and monitoring the discharge of displaced fluids and venting of gases. (iv)

Limiting the mixing of fluids at their interface.

(v)

Controlling and minimizing the formation of explosive gaseous mixtures at the gas/air interface.

(vi)

Removing unacceptable residues from the pipeline.

(vii) Continually discharging any static electricity generated to an effective earth (see AS/NZS 1020) (viii) A job hazard analysis.

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AS 2885.3—2001

(ix)

Appropriate signage.

(x)

Minimization of hydrocarbon discharge.

(xi)

Preventing the discharged fluid from causing unacceptable environmental effects such as damage to crops, excessive erosion, soil contamination or contamination of watercourses or bodies of water.

NOTE: See AGA Operating Section Report Purging Principles and Practice, Catalogue No. XK0775 as amended.

2.6.2 Filling a gas pipeline Prior to filling a gas pipeline, a plan shall be prepared, which shall contain all relevant supporting calculations. When a pipeline is being purged of air by the use of gas, prior to filling, consideration shall be given to the safety and operational consequences of the formation of an explosive mixture at the gas/air interface. A direct purge with gas may be used provided the approved procedures meet the conditions and requirements of AGA Operating Section Report Purging Principles and Practice, Catalogue No. XK0775 as amended. During purging gas should be released into one end of the pipeline in a controlled and continuous flow at an appropriate rate for the pipeline being purged. A slug of inert gas of sufficient length to separate the air from the gas to control the formation of an explosive mixture, may be released into the pipeline before the gas. Pigs or spheres may be used in some cases to reduce mixing at the interface and, therefore, reduce the volume of explosive mixture or reduce the volume of inert gas required. Where the above conditions cannot be met or controlled for the duration of the purge, then the operating authority shall ensure that the approved procedure, using an alternative technique, purges the pipeline in a safe manner. 2.6.3 Filling a liquid petroleum pipeline Prior to filling a liquid pipeline, a plan shall be prepared, which shall contain all relevant supporting calculations. The plan shall control the speed of the interface by applying appropriate back pressure at the gas release point. Where air in a pipeline is to be displaced by a hydrocarbon liquid, a slug of appropriate liquid between spheres or batching pigs should separate the air and hydrocarbon liquid. Where the slug in a pipeline is to be displaced by a hydrocarbon liquid, it shall be physically separated from the hydrocarbon liquid. The flashpoint of the initial hydrocarbon liquid introduced into a pipeline shall, where possible, be not less than 61°C, to prevent the formation of explosive gas/air mixtures. NOTES: 1 The operating authority should consider the risks of introducing lower flashpoint hydrocarbon liquid and take appropriate measures. 2 Physical separation using a batching pig is recommended. This can be improved using a slug of inert liquid or high flashpoint hydrocarbon in front of the pig to improve separation. 3 The use of an immiscible fluid like water may introduce contamination risks, and the risk of corrosion to the pipe invert where trace quantities may exist for long periods after the initial filling.

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2.6.4 Filling a high vapour pressure liquid (HVPL) pipeline Where the HVPL consists of a single component hydrocarbon, the pipeline may be filled in the gas phase in accordance with Clause 2.6.2, upon which the pipeline shall be pressurized to above the dewpoint of the HVPL and the pipeline confirmed as fully liquid. Procedures for the pressurization and recondensing of the gas phase HVPL shall be approved. Where the HVPL is a mixture of hydrocarbon components, the pipeline should be filled first with water or a suitable low vapour pressure hydrocarbon liquid, and then that liquid displaced by the liquid phase HVPL. Suitable spheres or pigs should separate the two liquids. The pressure shall be maintained at, or above, the bubble point of the HVPL, to maintain it in its liquid phase. NOTE: Where the HVPL consists of a mixture of hydrocarbon components other than ethane and the risk of contamination with inerts is considered low, the operating authority should complete a process simulation and prepare specific procedures to fill the pipeline in the gas phase. The operating authority needs to be aware of the effects of the variation of the composition of the recondensed HVPL along the pipeline, the potential low temperature effects and of the difficulty in determining when the pipeline is in a total liquid state.

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S E CT I ON

3

PI P E LI NE I NT E GRI T Y M AN AGE ME NT

3.1 BASIS OF SECTION For the purpose of this Standard, pipeline integrity management ensures that the high pressure pipeline infrastructure remains fit for purpose by implementing a systematic approach to the utilization of resources on high pressure pipeline system design, construction, operation and maintenance activities and the application of sound engineering principles with due regard to safety and the environment. The operating authority is responsible for ensuring continued Pipeline Integrity during the life of the pipeline. 3.2 GENERAL This Section details the key aspects of pipeline integrity management, which ensures the risks management strategies defined in the risk assessment carried out in accordance with the requirements of AS 2885.1, are implemented and managed effectively. Ongoing management of risks is required as part of a total pipeline risk management strategy. The operating authority shall ensure that approved actions, as a result of the risk assessment, and any other risk management assessments associated with operation and maintenance activities are documented and implemented. This Standard is based on pipeline integrity management principles. Pipeline integrity management as it relates to the operation and maintenance of pipelines covers the following: (a)

Pipeline structural integrity including the technical aspects of maintaining pipelines and facilities.

(b)

Threats to pipeline infrastructure.

(c)

Safety and the environment.

3.3 PIPELINE STRUCTURAL INTEGRITY Structural pipeline integrity is achieved when the pipeline is leak tight, operating within the design parameters and able to safely withstand all identifiable forces to which it may be subjected during operation, including the MAOP (see Section 5). In order to maintain structural integrity, the operating authority shall ensure that a pipeline has the following: (a)

Sufficient wall thickness at all locations to contain hydrocarbons at the system MAOP. The minimum allowable wall thickness shall be assessed as follows:

(i)

For a new pipeline, and for an in-service pipeline containing no corrosion anomalies or uniform general wall thickness loss, the minimum wall thickness shall be calculated in accordance with AS 2885.1.

(ii)

For a pipeline with physical damage, the minimum wall thickness shall be assessed in accordance with Clause 5.4.1 or other approved method.

(iii)

For a pipeline with corrosion anomalies, the minimum wall thickness shall be assessed in accordance with Clause 5.4.2.

(b)

Sufficient structural integrity at joints to prevent leakage at the MAOP.

(c)

An appropriate overpressure control system to ensure that the pipeline pressure does not exceed the MAOP during normal operation.

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The continued structural integrity of pipelines relies on elements of pipeline design, construction and operation and maintenance. Procedures shall be developed to ensure structural integrity of the pipeline infrastructure including compressor and pump stations, regulator stations, and metering facilities are retained during operation and maintenance activities. The procedures shall be approved. The operating authority shall address structural integrity issues of at least the following: (i)

Protective coatings.

(ii)

Pipeline wall thickness.

(iii) Valves, pig traps, launcher enclosures. (iv)

Pipe supports.

(v)

Cathodic protection systems/inhibition/corrosion control systems.

(vi)

Pressure control and protective equipment.

(vii) Stations. (viii) Casings. (ix)

Structures.

(x)

Joints.

3.4 THREAT MITIGATION 3.4.1 General The risk assessment, carried out in accordance with the requirements of AS 2885.1, requires that the operating authority identifies and assesses the risks associated with threats to the pipeline and instigates appropriate measures to mitigate these threats (see Section 6). To adequately manage risk, the operating authority shall develop, implement and monitor the threat mitigation measures and risk management procedures that have been identified in risk assessment, and documented and approved in the safety and operating plan. The minimum areas, identified in the risk assessment to be included in the safety and operating plan shall be the following: (a)

(b)

Physical measures: (i)

Separation by burial.

(ii)

Separation by barriers (e.g., crash barriers).

(iii)

Separation by exclusion (e.g., fencing).

(iv)

Resistance to penetration due to wall thickness.

(v)

Resistance to penetration by barriers (e.g., concrete slabs).

Procedural protection measures: (i)

One-call systems.

(ii)

Third party awareness programs.

(iii)

Landowner and emergency service liaison.

(iv)

Pipeline marking.

(v)

Marker tape.

(vi)

Patrolling.

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AS 2885.3—2001

(viii) Approved procedures (ix) (c)

(d)

Inspection or supervision of third party activities or proposed activities near the pipeline.

Operating authority review measures: (i)

Regular review of MAOP in accordance with Clause 8.6.

(ii)

Review of class location in accordance with Clause 8.7.

Operating authority activities: (i)

Coating assessment and repairs.

(ii)

Pipe wall assessment and repairs.

(iii)

Joint assessment and repair.

(iv)

Loss of cover repair.

(v)

Pigging.

(vi)

Venting.

(vii) Purging. (viii) High capacity utilization. (ix)

Incident response, review and prevention.

(x)

In-service modifications.

3.5 SAFETY AND ENVIRONMENT 3.5.1 General The operating authority shall ensure that all its actions and activities do not unduly expose its personnel, the public or the environment to unacceptable risks (see Section 7). Measures to mitigate these risks shall be documented in the operating and maintenance procedures and referenced in the safety and operating plan. Areas to be considered for inclusion in the safety and operating plan include the following: (a)

Safety of the public.

(b)

Safety of personnel working on the pipeline.

(c)

Safety of contractors.

(d)

Minimization of environmental impacts.

(e)

Incident management.

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AS 2885.3—2001

S E CT I ON

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4

P LANS

AND

P ROCE DURE S

4.1 GENERAL The operating authority, using the results of the risk assessment carried out in accordance with the requirements of AS 2885.1 and its experience and knowledge of the facilities and conditions under which they are operated and maintained, shall develop a safety and operating plan and procedures and emergency plan based on the relevant requirements of this Standard. Operating and maintenance personnel that are required to carry out these procedures shall be suitably qualified, trained and experienced to accepted industry standards. NOTE: These plans should be implemented prior to the pipeline bring placed into operation.

4.2 SAFETY AND OPERATING PLAN 4.2.1 General A safety and operating plan shall be written and it shall be approved. The plan shall be monitored reviewed and updated every two years if significant incremental change has occurred and, in any event, when the scope of any single change is significant. Significant change shall be considered to have taken place if any event initiates an operational, technical or procedural change in the elements covered by Items (a) to (g) listed below, or if the engineering design has been upgraded or modified. As a minimum, risk assessments shall be reviewed and updated to coincide with any update of the safety and operating plan. The safety and operating plan shall detail the policy of personnel, public and environment protection, as identified in the risk assessment, including measures to— (a)

protect the pipeline and associated installations;

(b)

promote public awareness of the pipeline;

(c)

operate and maintain the pipeline safely;

(d)

respond to emergencies;

(e)

prevent and minimize product leakage;

(f)

carry out inspections in accordance with Clause 5.3; and

(g)

ensure that the plans and procedures continue to comply with the engineering design.

4.2.2 Safety and operating plan requirements The safety and operating plan shall include, but not be limited to, the following: (a)

A description of the organization structure and responsibilities of key positions including the positions with approval authority for the procedures and plans.

(b)

A description of the pipeline system operation including suitable maps (alignment sheets) showing the route of the pipeline, the location of associated facilities such as compressor and pump stations, SCADA control centres, transmission towers, cathodic protection points, valve stations, metering points, and launching and receiving stations.

(c)

Risk assessment in accordance with the requirements of AS 2885.1 that includes—

(i)

a systematic review of threats identified in the risk assessment together with identification of any further operational threats, their potential causes, and the consequences (in qualitative terms) of such events;

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(d)

(e)

(f)

(g)

(ii)

the operational, maintenance and organization measures to eliminate those threats or reduce them to an acceptable level under AS 2885.1 (see Section 6); and

(iii)

the consequence analysis of any hazardous events and the design, operational, maintenance and organizational measures required to reduce the level of risk to as low as reasonably practicable (ALARP).

A summary of operational and maintenance processes and procedures for implementation of the required measures identified in Clause 4.2.2(c) including— (i)

maintenance schedule;

(ii)

operating procedures;

(iii)

a maintenance plan;

(iv)

pipeline inspections as detailed in Clause 5.3; and

(v)

cathodic protection surveys.

A summary of the contents of emergency response plans covering as a minimum— (i)

impact events;

(ii)

fire;

(iii)

rupture;

(iv)

leak/spill; and

(v)

natural events.

A summary of the records management plan addressing as a minimum— (i) the records to be maintained; (ii)

retention;

(iii)

storage methods; and

(iv)

record maintenance procedures.

Audit schedule.

4.2.3 Audit of compliance to safety and operating plan The operating authority shall, at periods defined in the safety and operating plan, conduct a full audit of each of the items listed in the safety and operating plan to determine that work is being carried out according to the plan and the written procedures. The audit shall identify any non-compliance with the plan or procedures. The operator shall then implement appropriate measures to rectify any non-compliance and ensure continuing pipeline integrity. Audits shall be carried out by appropriately qualified and experienced personnel. NOTES: 1 See Appendix B for a description of the document hierarchy. 2

See Appendix C for list of documents requiring approval.

4.3 EMERGENCY PLANS The following recommendations are given as a general guide with respect to preparing emergency plans: (a)

The number of experienced operative and supervisory staff should be adequate at all times to respond to any reported emergency event. Procedures should be established in order to ensure that personnel attend the site of the emergency as soon as possible in the circumstances. An emergency staffing structure and an up-to-date contact list of such personnel should be documented and maintained.

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(b)

Emergency procedures should be documented. All operational personnel should be made aware of emergency procedures and be fully trained in their application including any action required under such procedures.

(c)

Sound incident management procedures, covering the necessary planning and preparation to implement emergency actions in the event of an accident, a failure or other emergency may include the following: (i)

Promptly and expediently providing remedial action for the safety of the public and operating personnel, minimizing damage to property and protecting the environment.

(ii)

Liaising with the appropriate authorities, including the regulatory authority, and other relevant bodies.

(iii)

Limiting the quantity of and controlling any accidentally discharged fluid.

(iv)

Preventing or controlling the spread of vapour by the use of temporary flares, blow-downs, or other means.

(v)

Giving particular attention to those sections of the pipeline that present the greatest risk to the public or the environment or, because of construction features, have special requirements or extraordinary maintenance requirements.

(vi)

Critically reviewing and revising the plans and procedures at approved intervals.

(vii) Revising the plans and procedures whenever there is a change in the fluid or the operating conditions along the route or the equipment. (viii) Carrying out periodic simulated exercises at approved intervals, to determine the procedural correctness and the understanding by personnel of the emergency procedures. (ix)

(d)

Having adequate emergency equipment, pipe and fittings fit for the intended purpose readily available at all times, complete with traceable material test certificates.

Emergency plans should address the following: (i)

Attendance at the emergency site to analyse and develop a response plan.

(ii)

Precautions to take in the event of either HVPL or a gas cloud.

(iii)

Reduction of the pressure in the pipeline.

(iv)

Closure of any valves on each side of any dangerous or potentially dangerous situation.

(v)

Maintenance or curtailment of supply.

(vi)

Spill control.

(vii) Establishment of a control centre from which emergency activities may be coordinated. (viii) Instruction to the appropriate authorities and other relevant bodies of the action to be taken. (ix)

Evacuation of any endangered members of the public and unauthorized personnel.

(x)

Prohibition of road and rail traffic, low-flying aircraft and isolation of electrical power in any areas that may be hazardous to safety, to reduce any risk of ignition and resultant dangers.

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(xi)

AS 2885.3—2001

Expeditious transport of repair equipment, materials and personnel to the site.

(xii) Additional prudent action that any particular circumstances may require. (xiii) Distribution and control of plans. Emergency plans shall be reviewed periodically at periods not in excess of 2 years and, if necessary, shall be revised and approved. 4.4 PROCEDURES The operating authority shall— (a)

have written procedures (controlled document), which shall be approved and reviewed at nominated intervals, for the operation and maintenance of the pipeline and any associated systems, including those necessary for maintaining structural integrity in accordance with this Standard;

(b)

maintain a list of positions responsible for approval of operation and maintenance procedures and risk assessment as defined in the Standard;

(c)

document and record the interval between reviews of the safety and operating plan, emergency plan, and operation and maintenance procedures; and

(d)

operate and maintain the pipeline in compliance with these procedures.

The procedure specified in Clause 4.4(a) shall include detailed plans and instructions for persons responsible for the operation and maintenance of the pipeline during normal operation and maintenance. The operating authority shall maintain a record of training and competency of operation and maintenance personnel carrying out the operation and maintenance procedures.

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S E CT I ON

5

PI P E LI NE ST RUCT URAL I NT E GRIT Y

5.1 GENERAL The operating authority shall ensure that appropriate systems are identified, implemented and maintained to ensure pipeline structural integrity for the design life of the pipeline. 5.2 OPERATING AND DESIGN CONDITIONS The operating authority shall— (a)

operate a pipeline only when it conveys the fluid or fluids under the conditions (including subsequent changes) for which it was designed, constructed, tested, and approved;

(b)

ensure that during normal operation, the operating pressure at any point in the pipeline does not exceed the MAOP, and that transient pressure does not exceed 110% of the MAOP;

(c)

ensure that the operating temperature is such that the coating temperature rating and the thermal stress limits used in the pipeline design are not exceeded; and

(d)

ensure that operating conditions are such that the likelihood of stress corrosion cracking initiation or growth is minimized.

5.3 PIPELINE INSPECTION AND ASSESSMENT 5.3.1 General Periodic inspections shall be carried out to identify actual or potential problems that could affect the integrity of the pipeline. The operating authority shall plan and perform any maintenance required to rectify and manage any such problems. Inspections shall be carried out by approved and appropriately trained and experienced personnel. The inspection and assessment of a pipeline shall include the following: (a)

A full visual survey of all above-ground sections of the pipeline, including supports and associated equipment, to locate and assess any defects.

(b)

An audit of corrosion control facilities to assess their effectiveness in accordance with the corrosion-monitoring program required by this Standard. This includes cathodic protection systems, pipeline coatings, surge protection systems, static earth systems, and inhibitor dosing facilities.

(c)

Inspections of actual or potential problems identified in the ongoing risk assessment such as river or creek crossings, areas prone to ground instability and pipe supports at bridge crossings. NOTE: Where available, intelligent pigging results should also be considered when assessing pipeline integrity.

(d)

Inspections of any sections on the pipeline identified in the ongoing risk assessment as being of higher propensity for development of stress corrosion cracking.

5.3.2 Frequency of inspection assessment The frequency of inspection and assessment should be documented and approved and based on the past reliability of the pipeline, historical records, current knowledge of its condition, the rate of deterioration (both internal and external corrosion, coating degradation and the like), and statutory requirements. © Standards Australia

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AS 2885.3—2001

5.3.3 Leakage survey and detection The operating authority shall provide for leakage detection systems or periodic leakage surveys of the pipeline in its operating and maintenance plan. The types of surveys selected shall be effective for determining whether a potentially hazardous leakage exists. The extent and frequency of the leakage surveys shall be determined by the operating pressure, piping age, class location, whether the pipeline transports gas without an odorant and the ability to detect or observe product leakage. 5.3.4 Assessment of results and appropriate action Where the integrity of a pipeline, or a section of a pipeline, is assessed as being inadequate or at immediate risk, the operator shall immediately take steps to prevent failure of the pipeline until the integrity of the pipeline is restored. Measures shall be taken to mitigate the risk of a leak or failure to the minimum. This may be by a reduction in pressure, by passing, or by carrying out temporary repairs and appropriately adjusted surveillance. 5.3.5 Internal surfaces Notwithstanding the requirements of Clause 5.3.2 where a part of any pipeline is removed for any reason, the internal surface shall be inspected to confirm the suitability of, or the requirement for, an internal corrosion control program. Suitable measures shall be implemented to address any observed problems. 5.3.6 External surfaces 5.3.6.1 Above-ground pipelines Above-ground pipelines shall be inspected for evidence of corrosion or damage to or deterioration of any anti-corrosion coatings at intervals defined in the safety and operating plan, and the rate of corrosion shall be assessed. Where the rate of corrosion will reduce the design life, remedial action shall be taken. NOTE: Suitable action may include a reduction of the design life.

5.3.6.2 Buried and submerged uncoated pipelines Buried or submerged uncoated pipelines shall be surveyed using approved techniques at intervals as specified in the safety and operating plan. Pipelines shall be inspected at positions that are not more than 1 km apart and wherever the most corrosion is expected to occur. 5.3.6.3 Buried and submerged anti-corrosion-coated pipelines Whenever any part of a buried or submerged anti-corrosion coated pipeline is exposed, it shall be inspected for corrosion and evidence of damage to, or deterioration of, any anticorrosion coatings (see Clause 5.5.2). 5.4 PIPE WALL DEFECT ASSESSMENT 5.4.1 Damaged pipework Gouges, grooves and notches less than 0.25 mm are considered harmless. Gouges, grooves and notches above 0.25 mm and up to 10% of wall thickness may be removed by grinding. The requirements for non-destructive testing (NDT) for microcracking should be assessed. Wall thickness loss due to grinding may be assessed in the same manner as corroded pipework.

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Unless detailed analysis has been carried out to confirm the acceptability of an anomaly, anomalies in excess of the following shall be removed, replaced or otherwise repaired: (a)

Dents, as described in AS 2885.1 except that the maximum depth specified may be increased to 6% of the pipe diameter.

(b)

Gouges grooves and notches that are outside the criteria set out in AS 2885.1.

Combined pipe wall anomalies shall be subjected to detailed assessment. NOTE: Detailed analysis may be undertaken using CSA–Z662 Oil and Gas Pipeline Systems. This allows, subject to stated conditions, repair of dents containing stress concentrators by grinding, by pipe replacement, by pressure containment sleeve, or by reinforcement sleeve.

5.4.2 Corroded pipework 5.4.2.1 General Where corrosion is detected, it shall be investigated to determine its nature, extent, depth and cause. The corrosion shall be evaluated and the current MAOP shall be confirmed. In the event that the MAOP is determined to have been compromised, a safe operating pressure shall be determined by assessment in accordance with Clause 5.4.3 and, if necessary, either a new MAOP shall be established or the corroded portion of the pipeline shall be repaired or replaced. Corroded pipelines shall be protected against further corrosion in accordance with AS 2885.1. NOTE: Figure 5.1 provides a flow chart for assessing corrosion features.

5.4.2.2 Safety precautions Great care shall be taken when work is carried out on a corroded portion of pipeline. The operating pressure shall either not exceed the pressure at which the corroded portion was subjected to at the time of identification, or it should be reduced to a safe level (initially 80% of normal operating pressure). This pressure should not be exceeded until such time as the corroded area has been cleaned and inspected, the extent and depth of corrosion has been determined and an assessment has been made of the corroded portion of the pipeline. Prior to the commencement of any activity, an approved plan shall be prepared. Where the contents of the pipeline are liquid and locked in between valves, consideration shall be given to any increase in pressure that may be caused by changes in temperature. 5.4.3 Assessment of corroded pipework 5.4.3.1 General The assessment required by Clause 5.4.2.1 shall be made by any one of the following methods: (a)

Calculation, in accordance with Appendix D, Paragraph D3.

(b)

AGA Project PR3-805. NOTE: This program is based on the calculation method given in Appendix D, Paragraph D3 but is less conservative.

(c)

Pressure testing, in accordance with Clause 5.4.3.2.

(d)

Other approved method.

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NOTES: 1

The design pressure (Pd) shall be calculated as follows:

Pd =

2 Fd δ dp σ y D

where

2

Pd

= design pressure, in megapascals

Fd

= design factor


dp

= wall thickness for design internal pressure, in millimetres

y

= yield stress, in megapascals

D

= nominal outside diameter

Test pressure = 1.25 × Pd

FIGURE 5.1 FLOW CHART FOR ASSESSING CORROSION DEFECTS

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5.4.3.2 Assessment by pressure testing Where an assessment is to be made by pressure testing, the pipeline shall be tested in accordance with AS 2885.1 and its MAOP determined in accordance with Appendix D, Paragraph D2. The normal maximum pressure, recorded or determined for the corroded section over the six months prior to the discovery of the corrosion, may be deemed to be a test pressure for the purposes of recalculating the MAOP in accordance with this Clause. Where the original design included an allowance (G) (see AS 2885.1) and it can be shown that the original allowance is not required for the corroded section of pipe, a revised value for G may be used in the re calculation of MAOP. The revised value shall be approved. 5.5 COATINGS 5.5.1 Above-ground pipework Where, after inspection (see Clause 5.3.6.1), external corrosion that will compromise the integrity of the pipework before the next integrity assessment is identified, the operating authority shall take appropriate remedial action. This could include repair or renewal of the coating. Specific assessment of the coating should be made at crevice areas such as pipe supports and on the underside of the pipework. The pipe wall should also be inspected for corrosion at areas of blistered or disbonded coating. Where installed insulation shall be maintained in a condition such that— (a)

water cannot reach and collect next to the pipe surface; and

(b)

the requisite thermal insulation performance is maintained.

NOTES: 1 Corrosion under thermal or acoustic insulation can be a severe problem, especially if the pipeline is in intermittent service (i.e., subject to fluctuating temperatures encompassing the water vapour dewpoint). Inspection for corrosion under the insulation should be a regular feature of assessment surveys. 2 The coating system under insulation needs to be adequate to prevent corrosion under the conditions it will be subjected to. 3 Corrosion within crevices between surfaces, such as at pipe support saddles, can be a severe problem, which can be difficult to identify by simple visual inspection. 4 Coating inspection of ground entry locations should be in accordance with Clause 5.9.4.

Records of the coating condition shall be kept. 5.5.2 Below-ground pipework Assessment of the coating condition on below-ground pipework shall be achieved by evaluation of some or all of the following: (a)

Cathodic protection data.

(b)

Special coating defect surveys (eg. Pearson or DC-pulsed method surveys).

(c)

Visual inspection at selected locations in bellhole excavations and where the pipeline is exposed for other reasons.

The coating and/or the cathodic protection system shall be maintained to a standard such that— (i)

the cathodic protection system effectively maintains protection at all coating defects; and

(ii)

coating disbondment is minimized.

Records of the coating condition shall be kept. © Standards Australia

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5.5.3 Coating repairs Where a repair is made to a pipeline coating, the material used shall be compatible with the original coating and shall have been demonstrated by test, investigation or experience to be suitable for the method of installation, the service conditions and the environment. Procedures for application of the repair shall be developed so that the desired physical and chemical qualities are obtained. The application thereafter shall be in strict accordance with the procedures. Surface preparation, application and testing of the coating shall be subject to an approved quality control program. 5.6 CATHODIC PROTECTION 5.6.1 Criteria Criteria for pipeline cathodic protection shall be as specified in AS/NZS 2832.1 5.6.2 Personnel The parties responsible for the monitoring, survey, inspection, testing and maintenance of the cathodic protection system shall have the requisite experience and qualifications in cathodic protection as approved by the operating authority. NOTE: The Australasian Corrosion Association provides training for personnel in the Corrosion Prevention Industry.

5.6.3 Commissioning of cathodic protection systems Commissioning of cathodic protection systems shall be carried out in accordance with the requirements of AS/NZS 2832.1. 5.6.4 Operation, maintenance and monitoring of cathodic protection systems Operation, maintenance and monitoring of cathodic protection systems shall be carried out in accordance with the requirements of AS/NZS 2832.1 AS/NZS 2832.1 contains information in the following areas: (a)

Criteria for cathodic protection.

(b)

Measuring techniques and equipment.

(c)

Operation of cathodic protection systems.

Where any inspection indicates that satisfactory protection is not fully achieved on the pipeline, timely and appropriate action shall be taken to restore full protection or to instigate other measures that monitor corrosion 5.6.5 Measuring equipment Only approved measuring equipment and techniques in accordance with the requirements of AS/NZS 2832.1 shall be used. 5.6.6 Interference Interference testing shall be conducted in accordance with AS/NZS 2832.1 5.6.7 Records Records in accordance with the requirements of AS/NZS 2832.1 shall be retained for the life of the pipeline.

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5.7 INTERNAL SURFACES 5.7.1 Mitigation audits Where the design of the pipeline in accordance with AS 2885.1 includes the use of inhibitors and biocides as the method of corrosion mitigation, the operating authority shall confirm the suitability of the design on a regular basis. Where the mitigation method is found to be unsatisfactory, the method shall be revised to achieve the required level of corrosion control in accordance with AS 2885.1. 5.7.2 Personnel The parties responsible for the monitoring, testing and maintenance of the internal corrosion mitigation system shall have the requisite experience and qualifications as approved by the operating authority. 5.8 STATIONS 5.8.1 General The following requirements apply to stations for pumps, compressors, meters, mainline valves, pressure-regulators, odorizers, and the like. (a)

The area around stations shall be maintained in a clean and safe condition.

(b)

Entries, exits, and escapes routes shall be kept free from obstruction at all times.

(c)

Fences and gates shall be maintained to ensure the protection of the public and the equipment.

(d)

Start up, operating, and shutdown procedures for all equipment shall be established and followed. The procedures shall include details of the measures required to ensure that all equipment, including any shutdown control or alarm circuits, functions correctly.

(e)

Warning signs shall be maintained to ensure their accuracy, legibility and adequacy.

(f)

When deviations from the normal operating conditions that affect the safety of the pipeline occur, corrective action shall be initiated immediately. Where determined necessary, firefighting equipment shall be kept on site and maintained in good condition.

(g)

NOTES: 1 When the site is attended, sufficient personnel trained in the use of the firefighting equipment should also be in attendance. 2 AS 3788 should be considered for pressure vessel inspections. 3 The relevant sections of AS/NZS 3000 should be considered.

5.8.2 Pressure control and protective equipment inspection All pressure control and protective equipment, including regulators, controllers, relief valves and safety devices, shall be subjected to systematic inspection and testing in accordance with the maintenance plan to determine if they are — (a)

in good electrical, mechanical or hydraulic condition;

(b)

set to function at the correct level;

(c) (d)

properly installed and protected from foreign material or other conditions that might prevent proper operation; installed in a manner so as to prevent unauthorized operation or alteration;

(e)

operating correctly; and

(f)

adequate from the standpoint of capacity and reliability of operation.

Safety valves shall be maintained and tested in accordance with AS 1271. © Standards Australia

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5.8.3 Site security When a station is unattended, the site shall be appropriately secured. 5.8.4 Structure Structures housing equipment containing hydrocarbons, such as compressors, pumps, valve/regulator/meter pits or buildings, instrument rooms and laboratories, shall be inspected at approved intervals and shall be maintained in a safe condition. The inspection shall include the following: (a)

Testing of the atmosphere in the structure for toxic and combustible vapour.

(b)

Operation of ventilating equipment.

(c)

Structural integrity of pit covers.

(d)

Testing of any alarms.

5.8.5 Structures housing equipment A structure that houses equipment shall be inspected at intervals determined by experience with the equipment and the risk assessment carried in accordance with the requirements of AS 2885.1. It shall be maintained in good condition. The inspection shall include the testing of the atmosphere in the structure for toxic and combustible vapour. Leaks of these types shall be located and repaired. Ventilating equipment shall be maintained in a satisfactory operating condition. Ventilation ducts shall be cleared of any obstruction. A pit cover shall be examined to determine that it does not constitute a risk to the public, and that no damage to the equipment will result from unexpected loads on the cover. 5.9 ANCILLIARY EQUIPMENT 5.9.1 General In addition to the pipeline itself, equipment ancillary to the pipeline, and in particular the items listed in Clause 5.8, shall be regularly maintained. 5.9.2 Valves Valves and actuators require regular usage and maintenance to ensure they are functioning correctly. They should be inspected at approved intervals to ensure that— (a)

each valve is properly supported and that corrosion problems at support points are not occurring;

(b)

valves are secured to prevent unauthorized access and usage;

(c)

valve pits are structurally sound and that corrosion on fittings is not occurring;

(d)

valves are not leaking; and

(e)

valves and actuators are fully operable.

Valves including mainline valves and the emergency hand-operated equipment of remotely controlled valves shall be tested or operated at approved intervals to confirm operability. 5.9.3

Pipe supports

All pipe supports, for above-ground portions of lines, shall be inspected at approved intervals. The inspections shall establish the physical condition of each support, and verify that they are providing the required support for the pipe at that point. Where applicable, the interface between the carrier pipe and the pipe support shall be inspected for corrosion.

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5.9.4 Ground entry locations Severe corrosion can occur at the point where pipelines enter and leave the ground. Such points shall be inspected, in accordance with the maintenance plan, for coating deterioration and associated corrosion. NOTE: The inspection intervals are dependent on the coating type applied to the line.

5.9.5 Pig trap inspection and maintenance Maintenance of all components of pig traps (including end closure seals, bleed locks, electrical bonds, locking rings, pig signallers and fasteners) should be undertaken just prior to use, after painting or at approved intervals. In addition, temporary or removable pig traps should be inspected before use for mechanical damage (due to handling) and for evidence of corrosion. NOTE: Quick opening closures shall be operated and maintained strictly in accordance with the manufacturer’s instructions, particularly with regard to the yoke adjustments and pressurewarning devices.

5.9.6 Underwater pipelines The operating authority shall have measures in place so as to remain reasonably assured that, for underwater crossings — (a)

the depth of cover, if the pipeline is buried, remains adequate;

(b)

that scouring has not caused any part of the pipeline to be unsupported beyond allowable freespan length; and

(c)

that there is no accumulation of debris or silt that could affect the stability and safety of the pipeline.

In the event that the operation is not so assured, further inspections are to be undertaken. Additional inspections shall be made following severe floods, storms or earthquakes which could have affected the integrity of the crossing. Corrective action should be initiated immediately when inspection reveals an unsafe condition. 5.9.7 Tunnels, shafts and valve pits Tunnels and shafts shall be inspected at approved intervals to confirm— (a)

the structural integrity of the tunnel or shaft; and

(b)

the absence of leaks in the pipeline.

Corrective action shall be initiated immediately where the necessity for such action is revealed. A tunnel shaft or valve pit accessible by people may be a confined space. Such entry shall be controlled by the confined space entry procedure and permit in accordance with AS 2865. Valve pits shall be kept free of all matter that in any way could interfere with the operation of the valve. 5.9.8 Casings (sleeve) maintenance Schedules for pipeline maintenance should include appropriate checks on casings and attachments (e.g., checks for pipe to casing contacts or resistive bonds and gas detection of annulus vents for hydrocarbon).

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S E CT I ON

6

T HRE AT

MIT I GAT I ON

6.1 GENERAL The operating authority shall implement systems to ensure that all threats to pipeline integrity identified in the risk assessment carried out in accordance with the requirements of AS 2885.1 are adequately addressed to reduce the level of risk to ALARP. The effectiveness of the physical and procedural measures implemented to mitigate all identified risks and the corresponding risks shall be reviewed. 6.2 PIPELINE SURVEILLANCE 6.2.1 General Pipeline surveillance shall be carried out by the operating authority to ensure a pipeline is free from identifiable leaks and to identify any new or changed threats to the pipeline, particularly any unnotified external interference near the pipeline. The type of surveillance and the frequency required for safe pipeline operation varies and should be determined by risk assessment performed in accordance with AS 2885.1 and incorporated into the safety and operating plan. Factors to be considered in the risk assessment include, but are not limited to, the following (see Section 4): (a)

Operation of a ‘One-Call system’.

(b)

Whether the pipeline is above- or below-ground.

(c)

Other forms of protection against interference.

(d)

Activities by third parties that could affect the pipeline.

(e)

Location in a built-up area.

(f)

Locations close to environmentally sensitive areas.

(g)

Provision of a leak-detection system.

(h)

Regularity of use.

(i)

Nature of the fluid carried.

(j)

Design and operating pressure and temperature.

For a pipeline that is not regularly used, a patrol at frequent intervals may be maintained during use only, provided the line is isolated from sources of pressure when not in use. An annual patrol is required as a minimum. For a pipeline in regular or continuous use and provided the observer can clearly identify the pipeline and observe all the surveillance criteria (see Clause 6.2.2), the type of surveillance shall be by at least one of the following: (i)

Foot patrols.

(ii)

Vehicle patrol.

(iii) Aerial patrol. (iv)

Watercraft for underwater pipelines.

6.2.2 Patrol of route The route shall be patrolled and inspected in an approved manner at approved intervals as detailed in the safety and operating plan, and whenever it is considered that damage or threats to the integrity of the pipeline may have occurred or may be expected to occur. www.standards.com.au

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The route shall be accessible to authorized personnel, and clear access to valve stations shall be maintained. Corrective action shall be initiated immediately a condition requiring such action is detected. Particular attention shall be given to excavation, boring activities, including the use of an auger, and drains or ditches that are maintained and cleaned by an independent party. Surveillance criteria shall include the following: (a)

Variations to surface conditions such as erosion or earth movement.

(b)

Indications of leaks such as dead vegetation or evidence of liquid.

(c)

Construction activity or evidence of impending construction activity on or near the route.

(d)

Impediments to the access to the route, valve stations, pressure regulator stations, compressor stations, pump stations, cathodic protection sites, communication installations, and the like.

(e)

Deteriorating condition, visibility, adequacy and correctness of route markers and signs installed in accordance with the relevant requirements of Clause 6.3.

(f)

Security of sites and evidence of unauthorized entry.

(g)

Any specific action identified in the risk assessment.

(h)

Any other factors affecting the safety and operation of the pipeline.

(i)

Any factors likely to change the risk assessment such as urban encroachment and new developments.

The person conducting the patrol shall— (i)

be issued with written patrolling procedures;

(ii)

be appropriately trained in the procedures;

(iii) know the extent of the pipeline easement and the location of the pipeline; (iv)

be in radio/telephone communication with the pumping station/control centre; and

(v)

maintain a patrol log.

All surveillance patrol records shall be retained for the minimum period specified in the record management plan. 6.3 PIPELINE MARKING Signs shall be maintained along the route so that the pipeline can be properly located and identified from the air, ground, or both, as appropriate to each particular situation, as identified in the risk assessment. Maintenance of pipeline marking shall ensure the following: (a)

Legible signs are maintained at spacings as per the design documentation and in any case at the minimum requirements specified in AS 2885.1.

(b)

Signs at the landfall of submerged crossings or submarine pipelines shall be visible from a distance of at least 100 m on the water side of the landfall. NOTE: Illustrations of typical marker signs are shown in Appendix E.

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Maintenance of pipeline marking shall also include maintaining or adding — (i)

signs or other markers at each change of direction, at each side of permanent watercourses, at each side of road and rail crossings and at crossings of each property boundary;

(ii)

signs at all above-ground facilities; or

(iii) any other signs that identify the location of the pipeline. NOTE: Signage is intended to provide a visible indication of the existence of a pipeline in the vicinity. It is desirable to maintain a line of sight so that from any point on the right of way a sign is visible.

6.4 EXTERNAL INTERFERENCE PREVENTION 6.4.1 General The operating authority shall take all reasonable steps to inform people and organizations that may in any way rely upon the safety of the pipeline as follows: (a)

Informing the appropriate authorities and other relevant bodies of the hazardous properties of the fluid and the effects of any accidentally discharged fluid on the safety of the public so that, in the event of an emergency, prompt joint cooperative action can be taken. Procedures for cooperative action shall be established and maintained in the emergency plans required by Clause 2.2 and Section 4 of this Standard.

(b)

Informing landowners and other occupiers of land through which the pipeline passes of the methods of recognizing threats to the pipeline and an emergency situation. They should be supplied with 24 hour contact telephone numbers of the appropriate responsible persons or organizations to be notified in the case of an emergency. Warnings should be issued concerning the dangers of interference with the pipeline and its appurtenances.

(c)

Operating authority staff visits, at approved intervals, to provide landowners and other occupiers of land through which the pipeline passes with information to ensure that their activities do not endanger the pipeline and its appurtenances. To ensure the integrity of the pipeline and the safety of the public and the environment, it is critical that identified groups such as land use planners, developers, property and service designers, owners and operators, construction organizations, excavators, drillers and borers and the general public take into account the presence of the pipeline in their intended activities. Appropriate regular communication with these and with the relevant authorities is required to raise and reinforce awareness of the presence of a pipeline and the constraints with respect to the use of the land on and near the pipeline. The operating authority should identify all such parties on the basis of the requirements identified in the risk assessment and establish a liaison program with these groups, to ensure that, preferably in the concept stage, any changes in planning development or similar activities are advised to the operating authority. Appropriate consultation between the parties at this stage will ensure minimal impact on pipeline operations. NOTE: Where it is not possible to personally contact the identified parties consideration should be given to providing a package of information and contact details to the parties.

Third parties responsible for development work should be made aware that certain developments near the pipeline could require additional protection, as detailed in AS 2885.1. The operating authority shall include the constraints set out on land adjacent to the pipeline, when communicating with the relevant parties. www.standards.com.au

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6.4.2 Access to the pipeline The requirement for access to the pipeline easement shall be assessed. Where access is determined necessary, the easement shall be maintained to allow appropriate access by pipeline personnel and authorized contractors. 6.4.3 Prohibition of buildings near the pipeline The operating authority should have systems in place to ensure that no building or structure shall be allowed within a safe distance from the pipeline, as determined by the pipeline design and the risk assessment. Any parties intending to construct or erect a building or structure within this zone should first consult with, and obtain the approval of, the operating authority and, where an easement exists, the approval of the authority administering the easement. 6.4.4 Vegetation on and near the pipeline Unless approved, vegetation shall be restricted to allow free passage along the pipeline route. Vegetation, whose roots may damage the anti-corrosion coating of the pipeline, shall not be permitted in the vicinity of the pipeline. 6.5 CONTROLLING ACTIVITIES NEAR PIPELINES 6.5.1 General The operating authority shall take all reasonable steps to bring the following conditions to the attention of relevant parties and to enforce their imposition upon activities near pipelines: (a) A minimum of 48 working hours notice of intended activities near a pipeline should be given to the operating authority or operators so that arrangements can be made to have an operating authority’s representative on site during the work. (b)

Where third party works are to be conducted in the proximity of a pipeline so that the integrity of the pipeline is potentially under threat, the site shall be inspected, and where determined necessary, a work plan shall be specified and approved.

(c)

A representative from the operating authority shall be present during machine excavation that exposes a pipeline, to minimize the risk of pipeline damage.

(d)

No mechanical equipment shall be used within 1 m of the pipeline in any radial direction, even after the pipeline location has been proven, except when approved by, and under explicit ‘on-site’ direction from the operating authority’s inspector. Under no circumstances is mechanical equipment to be used closer than 0.3 m to the pipeline. Exposure of the pipeline shall be performed by hand digging, to minimize the risk of pipeline or coating damage. The minimum clearance from a pipeline for any buried structure shall be 0.3 m.

(e)

The minimum clearance for parallel installation shall be such that future maintenance can be conducted, but shall not be less than 0.5 m. The operating authority shall consider the following when determining appropriate separation distances of pipeline to other buried structures: (i)

Corrosion protection interference

(ii)

Penetration resistance.

(iii)

Rupture or explosion interaction.

(iv)

Access for maintenance.

(v)

Additional third party activity.

NOTE: Separation distances from the metallic structure forming part of electrical power generation, transmission and distribution systems should be determined on an individual basis as large currents can be discharged into the ground under fault conditions. © Standards Australia

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(f)

Any accidental damage to the pipeline, which affects the integrity of the pipeline in accordance with this Standard, shall be advised to the operating authority and, where legally required, to the regulatory authority.

(g)

All backfill within 150 mm around the pipeline shall be in accordance with AS 2885.1.

(h)

Where boring is to take place under or over a pipeline, approved measures shall be employed to ensure that the pipeline or its coating will not be damaged and a separation of at least 0.3 m between the pipe and bore is maintained.

6.5.2 Addition of fill on or near the pipeline Fill should not be added on or near the pipeline, as increased depth increases the cost of excavation and the poor stability of the fill increases the risk of cave-in during subsequent excavation. Where fill has to be added, the depth and quality shall be advised, prior to placement, for agreement by the operating authority. Any landscaping should be level within the easement or a minimum of 3 m (but preferably 6 m) each side of the pipeline, to permit excavating equipment to operate without having to destroy the adjacent landscaping. The addition of fill on or near the pipeline shall only be clean (preferably the same as the natural soil in that area) and shall not contain ash, salt or chemicals, which could have a deleterious affect on the pipeline. 6.5.3 Power and telegraph poles, fencing, seismic and land disturbance activities The operating authority should ensure adequate liaison so that parties undertaking such works adjacent to the pipeline advise the operating authority not less than 48 hours prior to commencement. This allows marking out the prohibited area and enables the operating authority to supervise, where appropriate, to prevent damage to the pipeline. The following activities need operating authority approval: (a)

The location of proposed new or replacement power and communications services poles and fencing across or along the easement or pipeline route. NOTE: Holes are only to be drilled and poles or posts placed after the operating authority has marked the exact pipeline location.

(b)

Land disturbance activities deeper than 300 mm, such as deep ripping, and the installation of drainage systems on the pipeline easement, or where no easement exists, a minimum of 3 m (but preferably 6 m) each side of the pipeline.

(c)

Any seismic activities near the pipeline, which need to be planned, and crossings designed to ensure that these activities do not affect the pipeline. NOTES: 1 The operating authority should advise seismic contractors of restrictions on working near the pipeline and the advance notice required to enable calculations and designs to be produced for actions to protect the pipeline during seismic work. 2 The operating authority should ensure that it is able to respond within a reasonable time to requests for seismic crossings.

6.5.4 Explosives The operating authority should ensure adequate liaison so that any person intending to use explosives does not do so within 30 m of the pipeline without the approval of the operating authority. Any use of explosives in the vicinity of the pipeline should be fully evaluated prior to granting approval.

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6.5.5 One-call-services Operating authorities shall register their assets with One-Call (or Dial Before You Dig) services, where available, for the benefit of members of the public seeking the location of buried assets prior to excavation. Third parties excavating in areas for which ‘One Call’ or ‘Dial Before You Dig’ services are available should be encouraged to seek from that service information about buried assets, at least 48 hours prior to excavating. 6.5.6 Operating Authority activities The operating authority shall, prior to undertaking activities that may affect the integrity of the pipeline, carry out measures to identify and mitigate threats to the pipeline. The types of activities that should be considered are as follows: (a)

Coating assessment and repairs.

(b)

Pipe wall assessment and repairs.

(c)

Joint assessment and repair.

(d)

Loss of cover repair.

(e)

Pigging.

(f)

Venting.

(g)

Purging.

(h)

High capacity utilization.

(i)

Incident reporting and response.

(j)

In-service pipeline modifications. NOTE: Apart from incident reporting to the regulatory authority where required by legislation, the circumstances of any incident, as defined in the Australian Pipeline Industry Association (APIA) Pipeline Operators Database, should be reported to APIA to enable statistics of pipeline incidents to be gathered.

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S E CT I ON

7

S AFE T Y

AND

E NVI RONME NT

7.1 GENERAL The operating authority shall ensure that the activities associated with operation and maintenance of the pipeline do not cause harm to personnel, contractors, the public or the environment. 7.2 EMERGENCY RESPONSE In the event of a pipeline emergency, the operating authority shall ensure that response to the emergency is performed in a planned and safe manner. The personnel responding to the emergency shall be trained in carrying out such procedure. The personnel and infrastructure shall not be exposed to unnecessary levels of risk. Measures to ensure that the operating authority is adequately prepared include the following: (a)

Documented emergency plan and procedures in accordance with Section 4.

(b)

Personnel training.

(c)

Simulation exercises.

(d)

Emergency response equipment.

(e)

Repair equipment.

(f)

Emergency services liaison.

(g)

Communications.

(h)

Public and customer relations.

(i)

Product containment/loss procedures.

7.3 VENTING PROCEDURES 7.3.1 Precautions to prevent an explosion Precautions shall be taken to prevent the accidental ignition of a possible hazardous concentration of flammable vapour or gas. Appropriate precautions may include the following: (a)

The display of suitable signs to advise the public about the extent of the hazardous area.

(b)

Where a cut in a pipeline is to be made by means other than a cutting torch, the installation of a metallic bond around that location.

(c)

Only electrical equipment, including radios, flashlights, and hand lanterns that are safe for use in a Zone 1 hazardous location, as defined in AS 2430.1, should be used.

(d)

When two flanges are to be separated, the installation of a metallic bond across the proposed break. Any impressed current cathodic protection system should be isolated but should be restored as soon as the work is complete.

(e)

The safe discharge of any static electricity (see AS/NZS 1020).

(f)

The prohibition of—

(g)

(i)

smoking and the presence of matches, lighters, and naked flame; and

(ii)

all sources of ignition from the work area, eg. spark-ignition engines, motor vehicles and mobile phones.

Electrical safety (see AS 2885.1)

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7.3.2 Venting gas In cases where venting of gas is to take place, reference should be made to the recommendations of IGE/SR/23, and the guidance contained therein should be applied as appropriate. The operating authority should ensure that venting is carried out in a safe manner with minimal impact on the environment. Consideration should be given to noise implications and the impact of a gaseous cloud. 7.4 PROCEDURES TO FREE PIPELINES OF HYDROCARBONS 7.4.1 General Hydrocarbon fluids shall be purged from a pipeline only when operating procedures dictate the need. Any purging of pipelines shall be in accordance with an approved procedure developed in accordance with the relevant requirements of Clause 2.6.1. 7.4.2 Gas When a pipeline is being purged of gas by the use of air after venting, consideration shall be given to the safety and operational consequences of the formation of an explosive mixture at the gas/air interface. During purging, air should be released into one end of the pipeline in a controlled and continuous flow at an appropriate rate for the pipeline being purged. A slug of inert gas of sufficient length to separate the gas from the air to control the formation of an explosive mixture may be released into the pipeline before the air. Pigs or spheres may be used in some cases to reduce mixing at the interface and, therefore, reduce the volume of explosive mixture or reduce the inert gas required. Where air movers are used to purge the pipeline or section of pipeline of gas, sizing of components should be carefully considered to ensure a continuous and adequate flow. Additional earth strapping should be used at the air mover location to discharge any buildup of static electricity. Where the above conditions cannot be met or controlled for the duration of the purge, the operating authority shall ensure that the approved procedure is suitable for the task. This procedure shall ensure that the pipeline is purged in a safe manner. Under certain conditions, a direct purge with air may be used, provided the approved procedures meet the conditions and requirements of AGA (XK0101-IN1). 7.4.3 Hydrocarbon liquid The following applies to hydrocarbon liquid: (a)

Where a pipeline is to be purged of hydrocarbon liquid, the purging fluid shall be water, air or a non-flammable gas.

(b)

Where the hydrocarbon has a flashpoint equal to or less than 61°C and is being purged with air, a batching sphere, a batching pig or slug of water between two spheres should be introduced between the air and the hydrocarbon liquid.

(c)

Where the hydrocarbon has a flashpoint greater than 61°C and is being purged with air, a batching sphere or a batching pig should be introduced between the air and the hydrocarbon liquid.

(d)

Where the hydrocarbon is being purged with water, an assessment should be made of the need to separate water from the hydrocarbon liquid with batching spheres or batching pigs.

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7.4.4 Purging an HVPL Where an HVPL is to be purged from a pipeline, the pressure in the pipeline shall be maintained at a value greater than the bubble point, at all points in the pipeline, until the purging is complete. The liquid phase purging operation shall be in accordance with Clause 7.4.3. Gas phase purging shall be used only where the pressure in the pipeline has accidentally fallen to less than the bubble point or where the HVPL is deemed to be a single hydrocarbon. The gas phase purging operation shall be in accordance with Clause 7.4.2. Dual-phase conditions shall be avoided. 7.4.5 Trapped hydrocarbon Where a pipeline or auxiliary equipment that has been in service is to be filled with air and there is a reasonable possibility that — (a)

the inside surfaces are wetted with a volatile combustible liquid;

(b)

a volatile combustible liquid may have accumulated in low places; or

(c)

gas may have accumulated,

a procedure designed to purge such liquids or gas shall be used. NOTES: 1 Filter vessels can accumulate combustible material, which may spontaneously ignite when exposed to air. 2 Transmission pressure may be trapped in valve body cavities and other blind off-takes.

7.5 COMMUNICATIONS SYSTEMS Adequate communication systems shall be used to ensure safe pipeline operation under both normal and emergency conditions. Systems allowing multiple simultaneous listening are preferred over one-to-one systems. 7.6 SCADA Where a pipeline is provided with a SCADA system, it shall be operated and maintained to the design to enable the safe operation of the pipeline. The following features incorporated in the design shall be maintained during the operational life of the pipeline — (a)

Reliability.

(b)

Supervision of the operation of the pipeline system.

(c)

The capability of issuing operating and control commands.

(d)

The capability of collecting and displaying data, facility alarms and status.

(e)

When specified, gather operating data and presenting it in a form that can be used by system operators and managers, including data required for the commercial operation of the pipeline.

(f)

Ensuring safe operation of control systems at remote facilities, irrespective of the condition of the SCADA system.

The design may also incorporate one or more of the following: (i)

A leak detection system.

(ii)

A business management system.

(iii) A personnel management system. Any changes to the system design shall be approved. www.standards.com.au

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7.7 PIPELINE FACILITY CONTROL Most facilities are remote from their point of operation and are generally designed for unattended operation. Each facility with a local system to manage the safe operation of the facility shall be operated and maintained to ensure functionality of the system design. The local control system shall— (a)

either continue to operate in the event of a communications failure or fail in a safe manner;

(b)

where electrically powered, in conjunction with an uninterruptible power supply, maintain the design capacity to ensure continuous operation throughout a reasonable power outage;

(c)

use reliable technology;

(d)

be maintained to fail in a safe manner; and

(e)

be maintained with appropriate security.

Each facility may also be configured to enable remote monitoring or control of the facility. Any changes to the system design shall be approved. 7.8 NOISE ABATEMENT A certain level of noise is inherent in operation and maintenance activities. The best practicable methods and industry standards should be employed to meet statutory requirements for the protection of site personnel and the general public. Special consideration should be given to the following: (a)

Provision of suitable ear protection to site personnel.

(b)

Siting and screening of plant.

(c)

The use of acoustically treated power tools, compressors, generators, air-coolers, vents and pipework.

(d)

The timing of all operation and maintenance activities, to take into account the impact on the environment.

7.9 ENVIRONMENT The operating authority shall establish an approved environmental management system in accordance with regulatory requirements. NOTE: The Australian Pipeline Industry Association (APIA) Code of Practice on environmental management should be referred to by the operating authority for guidelines on environmental management of pipelines.

7.10 ELECTRICAL SAFETY ON METALLIC PIPELINES Where a coated pipeline is exposed to threats from induced AC voltage (low frequency induction), earth potential rise effects, direct lightning strikes or DC voltage conduction (interference bonds to DC traction systems) a risk assessment shall be completed. Procedures shall be developed in accordance with ASN/ZS 4853, to ensure that the mitigation equipment installed as part of the design is maintained, and if necessary improved, to protect personnel from excessive touch voltages. Personnel shall be trained in these procedures.

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S E CT I ON

8

OPE RAT I NG CH ANGE S

CONDI T I ON

8.1 DESIGN CONDITION CHANGES The operating authority shall ensure that where any changes to the originally approved design conditions occur or are proposed, these changes are fully assessed to ensure the integrity of the pipeline is not impaired and that safety of the public, operating personnel or protection of the environment is not diminished. The changes may require the modification and re-approval of operating, maintenance and emergency procedures and to the MAOP and design life. The following list is given as a guide to items of change that should initiate an assessment: (a)

Process fluid.

(b)

Pressure and temperature.

(c)

Land use location class.

(d)

Pipeline damage or deterioration.

(e)

Pipeline modification.

(f)

Pipeline raising/lowering.

(g)

Pipeline route relocation.

(h)

Pressure control and protection systems including logic changes.

(i)

Design life extension.

The assessment shall include, as appropriate, a review of the following: (i)

The location class.

(ii)

The boundaries of the location class and the location of physical barriers or other features that could restrict the movement of these boundaries.

(iii) Management of risk to the public, property, environment or to the pipeline in accordance with AS 2885.1. (iv)

The protection measures required against third-party damage in accordance with AS 2885.1.

(v)

The physical characteristics of the pipeline, including the diameter, wall thickness, SMYS, fracture toughness properties, strength test pressure and leak test pressure. NOTE: These may be determined from records or, in the absence of records, by testing.

(vi)

The physical condition of the pipeline as determined from records of the operation and maintenance and from reports of examinations, inspections and monitoring, including those pertinent to corrosion mitigation.

(vii) The design pressure. (viii) The action that is required for the approval of a revised MAOP. The results of the investigation shall be used as the basis for the confirmation of, or the need to, review the MAOP, and shall be documented and approved.

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8.2 PRESSURE TESTING OF DESIGN CONDITION CHANGES Where a change in a design condition occurs, and where a pipeline, which has been strength-pressure tested previously to an appropriate pressure, is in good physical condition, the results of that strength test shall be used to determine the MAOP. Where a pipeline has not been strength-pressure tested previously to the pressure appropriate to the location or is in a poor condition, the pipeline shall be tested in accordance with AS 2885.1 and the results of that pressure test used to determine the MAOP. The condition of the pipeline shall be determined through a formal engineering investigation. 8.3 PIPELINE MODIFICATIONS Where a pipeline is modified and the modifications may result in a change to the MAOP, (e.g., the addition of a branch line or the inclusion of a pressure-containing component) the MAOP of the modified pipeline shall be determined in accordance with AS 2885.1, and approved. 8.4 REVIEW OF PRESSURE-CONTROL AND OVER-PRESSURE PROTECTION SYSTEMS Pressure-control and over-pressure protection systems, including compressor supplier packages control software, shall be suitable for and effective at the operating pressure and at the MAOP. Any changes to pressure-control and over-pressure protection systems shall be approved. Suitability of systems shall be reviewed at approved intervals and in conjunction with changes to supply capacity. 8.5 REVIEW OF DESIGN LIFE Where it is intended to operate a pipeline beyond its design life then, prior to the expiry of the design life, an engineering investigation shall be made of the design, operating conditions and history of the pipeline, to determine its condition and any limits for continued safe operation. The engineering investigation shall include verification of the following issues: (a)

Proof of structural integrity in accordance with this Standard, to confirm the pipeline can continue to contain the hydrocarbons at the design conditions.

(b)

Where the pipeline has been subjected to corrosion, as defined in accordance with AS 2885.1, the configuration of the defects, the rate of corrosion and the minimum remaining wall thickness shall be determined and used in the engineering investigation.

(c)

The completion of a fracture control plan in accordance with AS 2885.1, and the identification of the proposed fracture control methods.

(d)

The completion of a risk assessment conducted in accordance with AS 2885.1 and the identification of the proposed mitigation methods.

(e)

The identification of any additional requirements that enable the pipeline to comply with the latest versions of AS 2885.1 and AS 2885.2 current at the time of the review.

(f)

The identification of any tenure issue (ie. permit to occupy expiry) or statutory requirements (ie. pipeline licence renewal).

(g)

Review of the adequacy of the safety and operating plan, operating and maintenance, emergency response, and safety and environmental procedures.

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AS 2885.3—2001

Upon completion of the review, and prior to the expiry of the design life, all issues identified in the engineering investigation shall be addressed, and the pipeline records amended in accordance with the requirements of this Section. The pipeline shall be operated only under the conditions and the limits so established and approved. 8.6 REVIEW OF MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP) The MAOP of each pipeline shall be reviewed at approved intervals not exceeding 5 years and, if necessary, amended whenever there are changes (including corrosion or damage) that could adversely affect the safety of the public, the operating personnel or the integrity of the pipeline. Investigations, tests and calculations shall be made during the review to establish the current condition of the pipeline and to determine an MAOP in accordance with AS 2885.1, this Section and Appendix D. 8.7 REVIEW OF LOCATION CLASSES At approved intervals not exceeding 5 years and at any time when patrolling indicates the possibility of a need to change the classification of a location, the classification of the locations along the route of the pipeline shall be reviewed and, if necessary, changed. Appropriate corrective action shall be taken, including a risk assessment carried out in accordance with the requirements of AS 2885.1. 8.8 REVIEW OF RISK ASSESSMENT As part of any design review for change of use or extension of design life and at a period not exceeding 5 years (or as approved) an identification shall be made of the threats that could result in hazardous events affecting the pipeline. Threat mitigation procedures, failure analysis and risk evaluation shall be reviewed at those times. Notwithstanding the above, the risk assessment is a live document, and new or changed threats, and methods for their mitigation should be added to the risk assessment and operating procedures whenever they are identified. 8.9 OPERATION OF A SUSPENDED PIPELINE The operation of a pipeline shall be considered as suspended where the pipeline is maintained in a non-flowing condition for an extended period beyond the established maintenance routine. Where a pipeline is suspended for an indefinite period for a later alternative use, the following conditions apply: (a)

Where in accordance with AS 2885.1, the pipeline is considered as not being subject to internal corrosion, the hydrocarbon contents of the pipeline may be stored within the pipeline for the duration of the suspension.

(b)

Where in accordance with AS 2885.1, the pipeline is considered as being subject to internal corrosion, the pipeline shall be purged or flushed to remove all hydrocarbons, dried and filled with an approved fluid to an above-atmospheric pressure.

(c)

The normal pipeline operating functions of patrols, cathodic protection monitoring, corrosion and coating surveys and reporting shall continue in accordance with the operating procedures, and Sections 3 to 8 inclusive.

(d)

The level of pressurization shall be monitored.

(e)

Maintenance shall be completed to preserve the structural integrity of the pipeline in accordance with Section 5.

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The suspension of above-ground pipelines shall be subject to a risk assessment. The suspension of a pipeline shall be approved and subject to an annual review to determine if the pipeline should be abandoned. The decommissioning and preservation of associated plant shall also be completed. 8.10 ABANDONING A PIPELINE 8.10.1 General When a pipeline is to be abandoned, an abandonment plan, including an environmental rehabilitation plan, shall be compiled and approved. The sequence of decision making required to develop and implement the plan should be in accordance with Figure 8.10.1. When a pipeline is abandoned, it shall be disconnected from all sources of hydrocarbons that may be present in other pipelines, processing plant, meter stations, control lines and other appurtenances, and shall be purged of all hydrocarbons and vapour with a nonflammable fluid. Disposal of the purging fluid shall meet all relevant environmental and safety requirements. 8.10.2 Abandonment in place When abandonment in place is approved, the pipeline section shall be abandoned in such a way to ensure that ground subsidence and the risk of contamination of the soil or ground water is minimized. Where cathodic protection is applied, to prevent the eventual collapse of the pipeline, the responsibility for maintenance of the system shall remain with the pipeline operator and appropriate records shall be kept. NOTE: Consideration should be given to filling the abandoned pipeline with an inert substance.

8.10.3 Abandonment by removal When abandonment by removal is approved, the removal of the pipeline section shall meet all relevant safety, and environmental requirements. The requirements for pipeline removal shall be considered as similar to pipeline construction, and shall comply with the relevant requirements of Clause 9.4.3 and AS 2885.1. 8.11 ABANDONMENT OF ABOVE-GROUND PIPELINES Above-ground pipelines shall be abandoned by removal of the pipeline. 8.12 ADDITIONAL REQUIREMENTS FOR ABANDONMENT When a pipeline is abandoned, the following additional requirements shall be completed: (a)

The cutting of all buried pipelines at a minimum of 750 mm below natural surface or at the pipeline depth, whichever is the lesser.

(b)

The removal of all buildings, fences and equipment.

(c)

The removal of all signage associated with the pipeline on completion of the post abandonment maintenance period. Except where cathodic protection is required in accordance with Clause 8.10.2, the cathodic protection system including buried cables, impressed current units, power lines, solar arrays and batteries are to be removed. Anode and earthing beds are to be disconnected at 600 mm below the natural surface level.

(d)

(e)

All interference mitigation bonds with third party structures to be removed, that is the pipeline has to be mechanically and electrically disconnected from all other structures.

(f)

Obtaining landowner releases for the completed abandonment.

(g)

The relinquishing of the easement where no future or continuing use of the easement is proposed.

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8.13 ABANDONMENT RECORDS Where abandonment in place is approved, on completion of the abandonment of the pipeline section in situ, as executed drawings, complying with AS 1100.401, identifying and locating sections of the abandoned pipeline, shall be prepared as part of the relinquishment procedure. These records shall be made publicly available to prevent possible mistakes in identifying an abandoned pipeline as an operational pipeline. Records of approved changes of operating conditions, all engineering investigations and work carried out in connection with any change in the operating conditions shall be maintained until the pipeline is abandoned or removed.

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FIGURE 8.10.1 PIPELINE ABANDONMENT FLOW CHART

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S E CT I ON

9

PI P E LI NE

RE P AI RS

9.1 GENERAL Where a pipeline is damaged or corroded to the extent that continued operation would be unsafe, the pipeline shall be shut down or the operating pressure reduced to a safe level until such time as a repair is effected. 9.2 SUPERVISION Before any work is carried out on a pipeline, a competent person shall declare the work area safe in accordance with Clause 9.4. The person responsible for declaring the area safe, or an equally competent stand-in, shall remain alongside workers in that area until all work of a hazardous nature has been completed. 9.3 COMMUNICATION AND CONTROL A reliable communication system and procedure shall be established between the work site and all locations from which pipeline conditions can be controlled. 9.4 WORKING ON PIPELINES 9.4.1 General When any work is to be carried out on a pipeline, the formation of mixtures of flammable vapour or gas and air may occur. Mixtures of flammable gas shall be prevented from forming. This may be achieved by the exclusion of— (a)

air from spaces filled with hydrocarbon fluid; or

(b)

hydrocarbon fluid from spaces filled with air.

A safe condition shall be established. Where there is a likelihood of a gas leak, the area should be tested continuously to prove the absence of hazardous concentrations of flammable vapour or gas. The person(s) responsible for declaring the area safe shall remain alongside workers in that area until all work of a hazardous nature is completed. Equipment used in these situations shall be appropriate for such environments. 9.4.2 Tunnels, shafts, and casing The atmosphere in a tunnel, shaft, or casing, including those that are too small for human access, shall be declared safe by a competent person before any work is carried out on the pipeline within that tunnel, shaft, or casing (see Clause 5.9.7). 9.4.3 Construction safety Construction and repair of pipelines shall be carried out in a safe manner. The safety of the public, construction/repair personnel, adjacent property, equipment and the pipeline shall be maintained and not compromised. A construction or repair safety plan, including a job hazard analysis, shall be prepared and approved. As a minimum, the following items shall be addressed: (a)

Approved fire protection to be provided and local bushfire and other fire regulations shall be observed.

(b)

Where the public could be exposed to danger or where construction or repair operations are such that there is the possibility that vehicles or other mobile equipment could damage the pipeline, suitable warnings to be given.

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(c)

Where a powerline is in close proximity to the route and mobile construction equipment is in use, adequate danger signs to be installed.

(d)

Adequate danger and warning signs to be installed in the vicinity of construction operations, to warn persons of dangers, including those from mobile equipment, radiographic process and the presence of excavations, overhead powerlines and overhead telephone lines.

(e)

Unattended excavations in locations accessible to the public to be suitably barricaded or fenced off and, where appropriate, traffic hazard warning lamps to be operated during the hours of darkness.

(f)

During the construction or repair of submerged pipelines, suitable warnings to be given. Signs and buoys to be appropriately located to advise the public of any danger, and to minimize any risk of damage to shipping. Where warnings to shipping are required by an authority controlling the waterway, the authority's requirements for warning to be ascertained and the authority advised of all movements of construction equipment.

(g)

Adequate measures to be taken to protect the public from hazards caused by welding.

(h)

Procedure to be followed for lifting pipes both from the stockpile and into the trench after welding.

(i)

Procedures to be followed for the safe use and handling of chemicals and solvents.

(j)

The frequency of safety talks (toolbox meetings) to be determined and conducted.

(k)

An accident reporting and investigation procedure to be implemented.

(l)

A safety supervisor to be appointed with a detailing of duties, if applicable.

9.4.4 Precautions to prevent an explosion To prevent an accidental ignition of possible hazardous concentrations of flammable vapour or gas, appropriate precautions shall be taken and, where relevant, the following requirements shall apply: (a)

The work area to be monitored, using approved and correctly calibrated and tested flammable gas detectors prior to and during the work, to determine the presence and concentration of flammable gas.

(b)

Work to be suspended whenever a flammable gas concentration within the explosive range is detected.

(c)

The perimeter of hazardous areas to be determined and delineated.

(d)

Suitable signs that indicate to the public the extent of any hazardous areas to be displayed.

(e)

The following to be prohibited in hazardous areas: (i)

Smoking.

(ii)

The presence of matches, lighters and naked flame.

(iii)

The access of any sources of ignition to the work area (eg. spark-ignition engines, motor vehicles and mobile phones).

(f)

Electrical equipment, including radios, flashlights and hand lanterns, to be safe for use in Zone 1 hazardous locations as defined by AS 2430.1.

(g)

Adequate training and instruction to be given to operating and maintenance personnel about the possibility of electric surges (sparks) occurring across insulated joints.

(h)

Static electricity to be safely discharged (see AS/NZS 1020).

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(i)

Where two joining flanges are to be separated, an electrical connection to be installed across the proposed separation.

(j)

Prior to making a cut in a pipeline, the pipeline to be electrically earthed on each side of the location for the cut. NOTE: High voltages and currents can occur in pipelines as a consequence of lightning or a fault condition in nearby powerlines. Adequate precautions to prevent accidental injury or the creation of a source of ignition during any pipeline alteration work should be considered, such as the use of grounding mats or earth rods.

9.4.5 Pipelines filled with hydrocarbon gas 9.4.5.1 Where gas is escaping Where gas is escaping and a live repair is being carried out, thermal cutting, welding and other work shall only be carried out on the pipeline, when the following conditions, where practical and appropriate, prevail: (a)

Prior to commencement and throughout the process, a slight flow of gas within the pipeline is kept moving past any thermal cutting process and any welding process that is being undertaken.

(b)

The gas pressure is controlled by suitable means.

(c)

Any slots or open ends are sealed, as soon as they are made, with tape, tightly fitted canvas or other suitable means.

(d)

Only one opening is uncovered at any one time. NOTE: This is particularly important where the two openings are at different elevations.

(e)

Any escape of gas at the working location is ignited and kept burning.

(f)

Where the gas is toxic, adequate precautions are taken to protect the public and the work personnel.

9.4.5.2 Where gas is not escaping Work to be carried out on a gas pipeline from which gas is not escaping shall be in accordance with Clause 9.6. 9.4.6 Pipelines filled with liquid petroleum or HVPL Any cutting of pipelines, which contain or have contained liquid petroleum or HVPL that has not been purged, shall only be carried out by non-sparking mechanical means, and any heat generated shall be controlled below the product flashpoint. Welding shall not be carried out on a leaking pipeline filled with liquid petroleum or HVPL, unless the liquid and vapour are prevented from escaping from the pipeline or are suitably flared at a location remote from welding. 9.4.7 Purged pipelines Where a pipeline, which has been purged in accordance with Clause 7.4, is filled with air and is connected to a source of hydrocarbon fluid that cannot be completely isolated, welding, thermal cutting or repair operations shall not be permitted unless the flow of hydrocarbon fluid toward the work site is prevented and the pipeline contents at the work site are tested continuously to ensure that an unsafe concentration of hydrocarbon fluid does not occur. This may require— (a)

the generation of airflow away from the work within the pipeline, by the operation of air movers at suitable locations; or

(b)

the installation of stopples or spheres with bleed vents on each side of the work site, taking care that this does not prevent adequate airflow that may be required in Item (a) above.

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9.5 REPAIR STRATEGY 9.5.1 Initial response Immediately a leak is detected, corrective action shall be initiated. Damage should be evaluated promptly. Where a pipeline is damaged or corroded to the extent that continued operation would be unsafe, the pipeline shall be shut down or the operating pressure reduced to a safe level, until necessary repairs have been completed and inspected and it is safe to resume normal operation. 9.5.2 Repair strategy flow chart The operating authority shall plan a repair strategy taking into account the process shown in Figure 9.5.2. 9.5.3 Temporary repairs Temporary repairs may only be made when immediate shut down is not practicable, provided that as soon as possible they will be made permanent in accordance with Clause 9.5.4. 9.5.4 Permanent repairs Permanent repairs shall be made to a pipeline, subject to the following conditions: (a)

On a liquids pipeline, the defect has been sealed or suitably vented to prevent leakage during repair.

(b)

The internal pressure is at a low enough level to ensure safety during the repair operation.

(c)

Grinding in the area containing the defect is limited to a depth that will ensure safety during the repair operation.

(d)

Safety precautions comply with Clauses 9.2 to 9.4.

(e)

Cutting and welding comply with Clauses 9.6 and AS 2885.2. and welding procedures ensure that pipe walls are not reduced in thickness or weakened.

(f)

Where a section of pipe or reinforcement containing a defect is replaced, the replacement pipe is pre-tested and its properties verified such that the integrity of the pipe is not less than that of the section to be replaced, and the repaired section does not impede the passage of the type of pig for which the pipeline was designed.

(g)

Pressure-containing full-encirclement welded split sleeves used to effect repairs have design pressures determined in accordance with AS 2885.1, subject to the MAOP of the pipeline not being reduced.

(h)

The use of mechanical devices other than full-encirclement welded sleeves to repair pipeline defects have the type, installation and pressure rating approved, operators installing such devices have been trained and approved to conduct such work. NOTE: The use of reinforcement sleeves or mechanical devices for permanent repair of pipeline internal corrosion defects is not recommended as — (a) the passivation of the internal corrosion cannot be guaranteed; and (b) it is required to establish the internal corrosion mechanism. A fully welded encirclement sleeve is the recommended method of repair.

(i)

The carbon equivalent of materials, which are to be welded into the pipeline, conform to that specified in the certified weld procedure in accordance with AS 2885.2. NOTE: Guidance on methods for the repair of pipelines is given in WTIA Technical Note 20.

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AS 2885.3—2001

9.6 WELDING ONTO AN IN-SERVICE PIPELINE 9.6.1 General Welding onto an in-service pipeline shall be in accordance with the relevant requirements of AS 2885.2. 9.6.2 Monitoring of operating conditions The operating authority shall ensure that the welding procedures used are appropriate for the task and that the required operating conditions and controls are defined in the approved procedure. Whilst any welding is in progress, the pressure and flowrate of the fluid or heatsink capacity measurement shall be adequately monitored. Welding shall be discontinued at any time when the pressure, flowrate or heatsink capacity measurement is outside the limits specified in the approved procedure. 9.6.3 Resumption of normal operation The pressure in a pipeline following a repair shall not be increased, until the repair has been inspected in accordance with this Standard and AS 2885.2 and the inspection has demonstrated that it is safe for normal operation to be resumed.

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FIGURE 9.5.2 REPAIR STRATEGY FLOW CHART

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9.7 HOT-TAPPING OPERATIONS Any hot-tapping operation shall be carried out by trained and experienced persons and in accordance with an approved written procedure that incorporates the appropriate job hazard analysis, emergency procedures and safety precautions. The detailed procedure shall be based on shop tests, experience, practice runs and other relevant information. This procedure shall be followed throughout the operation. Operating personnel should be thoroughly familiar with the procedure before the hot-tap operation is commenced. The procedure should address the following: (a)

Safety of personnel, public and the environment.

(b)

Product containment.

(c)

Site control and use of a permit.

(d)

Specific welding and NDT requirements as specified in AS 2885.2.

(e)

Testing requirements.

(f)

Coating and backfill.

(g)

Emergency procedures.

(h)

Testing and operation of hot tapping tool and fittings.

(i)

Traceability of materials. NOTE: See WTIA Technical Note 20 and AS 2885.2.

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S E CT I ON

1 0

RE CORDS

10.1 GENERAL The Operating authority shall obtain and maintain records that are necessary to safely operate and maintain the pipeline and to determine the fitness for purpose of the pipeline at any stage of the pipeline operating life. 10.2 DESIGN, CONSTRUCTION AND COMMISSIONING RECORDS During the design stage, receipt of materials for the pipeline, and pipeline construction, the operating authority shall obtain, prepare and keep current, records of the following: (a)

The design criteria.

(b)

Risk assessments conducted in accordance with AS 2885.1.

(c)

Hazard and operability study records.

(d)

The traceability of all materials and components including all test results and inspection reports.

(e)

All tests and inspections that are required to verify the integrity of the pipeline in accordance with AS 2885.1 or AS 2885.2.

(f)

The MAOP that is required by Section 8.

(g)

All drawings, as built and alignment (developed in accordance with AS 1100.401) relating to the pipeline and facilities.

(h)

Charts and maps showing the location of cathodically protected pipelines, cathodic protection equipment and structures affected by or affecting the cathodic protection system.

(i)

Cathodic protection potential readings, cathodic protection unit outputs and interference current readings.

(j)

The condition of the internal and external surfaces.

(k)

A list of the authorities that have granted easement rights or other operating permits, and land-holders through whose land the pipeline passes, including contact history and title information.

(l)

A list of other easements (especially easements in gross for other pipelines, power lines and communications cables) through which the pipeline passes, their contact details and other relevant information.

(m)

Records of pipeline sections or components identified as potentially high risk in an emergency.

(n)

Commissioning records.

(o)

Quality assurance records and traceability

(p)

Safety and environment records.

(q)

Approvals and correspondence with regulatory authorities.

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10.3 OPERATION AND MAINTENANCE RECORDS The operating authority shall prepare a records management plan. The records management plan shall detail the records to be obtained, the records to be retained, storage methods and procedures to maintain currency of the records, until the abandonment of or removal of the pipeline. This plan shall be approved. Records that shall be included in the plan are the following: (a)

Records required under Clause 10.2.

(b)

Any approved change to operating conditions, engineering investigations and any work carried out in connection with any changes to operating conditions.

(c)

Any modifications to the maps, charts, plans, drawings and procedures, which are required to allow the procedures to be properly administered (e.g., exposure to the public, changes in design and operating conditions).

(d)

Details of any corrosion.

(e)

Details of the cathodic protection system as required to be recorded by AS/NZS 2832.1.

(f)

Details of any leaks, ruptures and other damage.

(g)

Routine inspections, and inspections and testing carried out when cutting a pipeline or making hot taps.

(h)

Repairs and maintenance work to pipelines and stations.

(i)

Details of inspections of internal or external pipeline condition.

(j)

Details of any coating inspections and repairs.

(k)

Correspondence with statutory and regulatory authorities.

(l)

Risk assessment reviews.

(m)

Incidents and subsequent preventative actions.

(n)

Operation and maintenance personnel competency details.

(o)

MAOP review documents.

(p)

Location class review documents.

(q)

Reports on landholder and third party liaison and the information given.

(r)

Records of emergency response exercises, the actions arising, and the completion of those actions.

The operating authority shall also prepare and retain for a minimum of 5 years records of the following: (A)

Necessary operational data.

(B)

Pipeline surveillance patrol reports.

10.4 ABANDOMENT RECORDS The operating authority shall document the archiving or disposal of records associated with an abandoned pipeline. A record should be kept of all abandoned pipelines that remain in situ, to prevent possible mistakes in identifying an abandoned pipeline as an operational pipeline as required by Clause 8.12. Where cathodic protection is applied, to prevent the eventual collapse of the pipeline, the responsibility for maintenance of the system shall remain with the pipeline operator and appropriate records shall be kept. www.standards.com.au

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APPENDIX A

LIST OF REFERENCED DOCUMENTS (Normative) A1 IDENTIFICATION OF DOCUMENTS The prefix letters in the document number identifies the name of the issuing body of each document as follows: AGA American Gas Association AS Australian Standards AS/NZS

Australian and New Zealand Standards

ASTM

American Society for Testing and Materials

CSA

Canadian Standards Association

IGE WTIA

Institutions of Gas Engineering, UK Welding Technology Institute of Australia

A2 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1100 1100-401

Technical drawing Part Engineering survey and engineering survey design drawing 401:

1271

Safety valves, other valves, liquid level gauges, and other fittings for boilers and unfired pressure vessels

1929

Non-destructive testing — Glossary of terms

1978

Pipeline — Gas and liquid petroleum — Field pressure testing

2430 2430.1

Classification of hazardous areas Part 1: Explosive gas atmospheres

2812

Welding, brazing and cutting of metals — Glossary of terms

2865 2885 2885.1 2885.2

Safe working in a confined space Pipelines—Gas and liquid petroleum Part 1: Design and construction Part 2: Welding

4343

Pressure equipment — Hazard levels

AS/NZS 1020

The control of undesirable static electricity

2832 2832.1

Cathodic protection of metals Part 1: Pipes and cables

3000

Electrical Installations (Known as the Australian/New Zealand Wiring Rules

3788

Pressure equipment — In-service inspection

4853

Electrical safety on metallic pipelines

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AGA PR3-805

A modified criterion for evaluating the remaining strength of corroded pipe (RSTRENG)

XK0101-IN1

Purging principles and practice, 3 rd edition, 2001

API 5L

Specification for line pipe

ASTM A53

Specification for pipe, steel, black and hot-dipped, zinc-coated welded and seamless

A106

Specification for seamless carbon steel pipe for high-temperature service

A381

Specification for metal-arc-welded steel pipe for use with high-pressure transmission systems.

CSA Z662

Oil and gas pipeline systems

IGE SR/23

Safety recommendation—Venting of natural gas

WTIA Technical Note 20

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Repair of steel pipelines

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APPENDIX B

DOCUMENT HIERARCHY (Informative)

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AS 2885.3—2001

APPENDIX C

LIST OF APPROVAL REQUIREMENTS (Informative) C1 CONCEPT OF APPROVAL The concept of approval is a central element of this Standard. Approval requires a conscious act to be performed in formally reviewing the item to be approved, as defined by this Standard, recording the review has taken place and accepting responsibility for the implications of acceptance. Throughout this Standard items are identified as requiring approval. These items are considered crucial to the objective of providing and retaining safe and reliable pipeline infrastructure. The principles that follow detail the types of items that have been designated as requiring approval. C2 PRINCIPLES The following constitutes the principles of approval: (a)

Parameters, acceptance criteria or values that are not explicit in AS 2885.3 (this Standard) which have to be determined by the operating authority and have to be approved.

(b)

Parameters, acceptance criteria, values or answers derived from processes required by AS 2885.1 or AS 2885.3 (this Standard) have to be approved. In the case where other approved methods are allowed by the Standard, these have to be demonstrably no less stringent than the recommended methods.

(c)

Deviations from the Standard or exemptions from the Standard or the application of Clause 1.3 have to be approved. This includes the use of Standards not expressly nominated in the AS 2885 series.

(d)

Items where AS 2885.3 does not define a unique requirement, but provides a generic basis or guideline, have to be approved.

(e)

Unique or unusual technical items for which AS 2885.1, AS 2885.2 or AS 2885.3 (this Standard) do not have specific or complete requirements.

C3 LIST OF APPROVED ITEMS The following list of items is considered to be the minimum requirement for compliance with this Standard: (a)

The authorities and organizational structure....................................Clauses 4.2.2, 4.4.

(b)

Matters relating to safety, engineering design, materials, testing and inspection.............................................. Clauses 2.4, 3.3, 3.4, 5.4.2, 5.4.3.

(c)

Non-compliance with AS 2885.1 ...............................................................Clause 1.3.

(d)

Safety and operating plan including emergency plan. ............... Clauses 2.2, 4.2.1, 4.3.

(e)

Maintenance plan and schedule .............................................................. Clause 4.2.2.

(f)

Environmental code of practice to deal with possible pipeline leaks............................................................................................Clause 2.2.

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(g)

Risk assessment actions and measures ............................................Clauses 3.2, 4.2.2.

(h)

Review intervals .................................................... Clauses 4.2, 4.3, 4.4, 6.4, 8.4, 8.7.

(i)

Patrol frequency and techniques ............................................................. Clause 6.2.2.

(j)

Pipeline inspections .................................................................. Clauses 4.2.2(d), 5.3.

(k)

External interference......................................................................Clauses 6.4.3, 6.5.

(l)

Purging and filling pipelines (commissioning) ...........................................Clause 2.6.

(m)

Venting and purging pipelines ...........................................................Clauses 7.4, 8.9.

(n)

Operating, maintenance and repair procedures ...................................Clauses 2.2, 4.4.

(o)

Cathodic protection surveys ........................................................ Clauses 4.2.2, 5.6.2.

(p)

Measuring equipment for corrosion protection assessment ...................... Clause 5.6.5.

(q)

Pipeline and coating assessment repair, techniques and plans ........................................................................Clauses 5.3.2, 5.3.6.2, 5.5.3.

(r)

Tie-ins to existing facilities ...............................................................Clauses 2.4, 9.7.

(s)

Hot tapping, welding and repair procedures .......................................Clauses 9.6, 9.7.

(t)

Personnel and contractors training and experience to perform tasks .................................................................... Clauses 5.3.1, 5.6.2, 9.5.4.

(u)

Modifications and changes to design criteria.......................................................Clauses 7.6, 7.7, 8.1, 8.3, 8.4,8.5, 8.6, 8.7.

(v)

Suspension, abandonment plan and rehabilitation plan .....................Clauses 8.9, 8.10.

(w)

Construction or repair safety plan........................................................... Clause 9.4.3.

(x)

Other mechanical repair devices ........................................................Clause 9.5.4 (h).

(y)

Records management plan....................................................................... Clause 10.3.

(z)

Environmental management system ...........................................................Clause 7.9.

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APPENDIX D

ASSESSMENT OF A CORRODED PIPELINE (Normative) D1 SCOPE This Appendix sets out approved methods that may be used when the suitability for service of a pipeline having corrosion damage is being assessed. The methods in this Appendix are relevant to assessments based on pressure testing or calculation. A logic diagram for a calculation method is shown in Figure D1. NOTE: The methods described in this Appendix are used for assessing individual corrosion anomalies. For complex corrosion, including closely linked corrosion anomalies, engineering judgement and experience should be used.

D2 ASSESSMENT BY PRESSURE TESTING The MAOP of a pipeline that is corroded, but is otherwise satisfactory, may be determined by re-testing the corroded section of the pipeline hydrostatically to a pressure that would not cause the pipe to leak or lose its integrity. This would be carried out only after the appropriate safety measures had been taken and an estimate of the appropriate test pressure made (see AS 1978). NOTE: The operating authority should consider the possibility of the propagation of stress corrosion cracking.

Following a successful re-test, the MAOP for the pipeline is established by dividing the retest pressure by 1.25 (1.1 for appropriate parts of telescoped pipelines). Where a pipeline that is corroded has been operating successfully, the recent operating history at the time and place where corrosion has occurred may be used as a successful test pressure and it is not necessary to re-test the pipeline. The MAOP for the pipeline is determined by using the operating pressure as the re-test pressure and dividing this by 1.25 (1.1 for appropriate parts of telescoped pipelines). Where the thickness of the pipeline is reduced by corrosion, and corrosion is expected to continue, an allowance shall be made. In the analysis that follows, the MAOP is used in place of the test pressure as in the relevant equation (see Equation D4 or D5). One is expressed as a proportion of the other and any common multipliers would cancel out. D3 ASSESSMENT BY CALCULATION D3.1 General As an alternative to the determination of a MAOP from a pressure test, it may be preferable to calculate the pressure at which the pipe is expected to fail. This may be carried out by using a method of hoop stress analysis. One method is shown in Paragraph D3.2. The pressure at which the corroded pipe would fail occurs when the pressure causes the sound metal beneath the corrosion to fail. If the test pressure calculated from the hoop stress analysis is equal to or greater than the original test pressure, the MAOP need not be reduced. If this calculated pressure is lower than the original test pressure, the MAOP is determined by dividing the calculated pressure by 1.25 (1.1 for appropriate parts of telescoped pipelines).

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D3.2 Hoop stress analysis D3.2.1 General This Method of hoop stress analysis begins with the calculation of the critical length of the corroded area, which is appropriate to the measured depth and the original MAOP. Where the projected length is less than the critical length, further calculations are not necessary and the MAOP is confirmed. Where the projected length is greater than the critical length, further calculations are necessary. A systematic approach is given in Steps 1 to 8 of Paragraph 3.2.3. Steps 1 to 5 give verifications or otherwise of the original MAOP, by calculation of the critical length of the corrosion. Steps 6 to 8 give the method for the calculation of a new MAOP. Step 6 is the appropriate method for relatively long or shallow corrosion as it overestimates the area of corrosion. Consequently, the new MAOP is not dependent on the length of the corrosion. In the limiting case where shallow corrosion occurs, i.e., dc/δN is not greater than 0.1, no reduction in the original MAOP is necessary. The use of Figure D3, Figure D4, and Figure D5 is recommended as the graphical solution is sufficiently accurate. The limitations on the use of the equations are shown graphically. Where the corroded pipe has a wall thickness greater that the pressure design wall thickness and this is to be used in the analysis, formal calculations, rather than a graphical method, should be used to justify the final recommendation. Eight solutions are presented to illustrate a range of typical corrosion depths and lengths. NOTE: The derivation of the method shown in this Appendix, and a review of the test program that confirmed the method and discussion on the Folias factor are given in the American Gas Association, 5th Symposium on Line Pipe Research Catalogue No L30174—Chapter L, 1974.

D3.2.2 Limitations Hoop stress analysis has the following limitations: (a)

It is limited to corrosion on weldable pipeline steels categorized as carbon steels or high strength low-alloy steels. Typical of these materials are those described in ASTM A 53, A 106, and A 381, and API 5L.

(b)

It applies only to defects in the body of line pipe, which have relatively smooth contours and cause low stress concentration (e.g., electrolytic or galvanic corrosion, loss of wall thickness due to erosion).

(c)

It should not be used to evaluate the remaining strength of — (i)

corroded girth welds;

(ii)

longitudinal welds;

(iii)

related heat-affected zones;

(iv)

anomalies caused by mechanical damage, such as gouges and grooves, that have not been assessed in accordance with Clause 5.4.1; or

(v)

defects introduced during pipe or plate manufacture, such as seams, laps, rolled ends, scabs, or slivers.

(d)

The criteria for corroded pipe to reman in service are based only upon the ability of the pipe to maintain structural integrity under internal pressure. It should not be the sole criterion when the pipe is subject to significant secondary stresses (e.g., bending), particularity if the corrosion has a significant transverse component.

(e)

It does not predict leaks or rupture failures.

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D3.2.3 Review of corrosion parameter The procedure is as follows: (a)

Step 1— Depth of corrosion Measure the depth of corrosion (dc) and express it as a ratio of the nominal wall thickness (δN ) for the pipe. Evaluate this ratio as follows: (i)

Where d c/δN is equal to or less than 0.1, the MAOP (po) need not be reduced.

(ii)

Where d c/δN is equal to or greater than 0.8, the corroded pipe shall be repaired.

(iii)

Where d c/δN is greater than 0.1 but less than 0.8, proceed to Step 2.

(b)

Step 2— Length of corrosion Measure the projected length of corrosion (L p).

(c)

Step 3— Constant K f Calculate the value of the constant Kf from the following: (i)

Where d c/δN is less than or equal to 0.18, the value of the constant Kf is 4.

(ii)

Where d c/δN is greater than 0.18, the value of the constant Kf shall be determined from Figure B3 or calculated from the following equation: 2    dc /δ N Kf =    −1   (1.1 d c / δ N ) − 0.15 

(d)

(f)

(i)

Where the critical length (L c) is greater than the projected length (L p), the MAOP (p o) need not be reduced.

(ii)

Where the critical length is less than or equal to the projected length, the value of the constant Kc shall be calculated and compared with 4 and a new MAOP (p c) calculated.

Step 6— Constant Kc Calculate the value of the constant Kc from the following equation: −1 / 2

. . . D3

Step 7— Value of Kc less than or equal to 4 Where the value of the constant Kc is less than or equal to 4, the new MAOP (p c) shall be determined from Figure B4 or calculated from the following equation:   1 − 2 d c / 3δ N  p c = 1.1 po  1/ 2  2 1 − 2 /[3 ( + 1 ] ) dc δ N Kc  

(h)

. . . D2

Step 5— Evaluation of the MAOP of corroded pipe Evaluate the MAOP of corroded pipe as follows:

K c = 0.893 L p ( D δ N ) (g)

. . . D1

Step 4— Critical length of corrosion Calculate the value of the critical length (L c) from the following equation: 1/ 2 L c = 1.12 K f (D δ N )

(e)

1/ 2

  

. . . D4

Step 8— Value of Kc greater than 4 Where the value of the constant Kc is greater than 4, the new MAOP (p c) shall be determined from Figure D5 or calculated from the following equation: p c = 1.1 po (1 − d c / δ N )

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. . . D5

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D3.2.4 Example Determine the MAOP of a corroded pipe having an outside diameter (D) of 762 mm, nominal wall thickness (δN ) of 6.35 mm, and the maximum depth of the deepest pit in the corroded area (d) of 3.2 mm in Case (i) and 0.5 mm in Case (ii). The measured length of the corroded area projected onto the longitudinal axis of the pipe (L p) is, in each case — (a)

5 mm;

(b)

100 mm;

(c)

300 mm; and

(d)

1000 mm.

Case 1 DEPTH OF CORROSION 3.2 mm Step 1—Depth of corrosion Express the depth of corrosion as a ratio of the nominal wall thickness, i.e., d c/δN = 3.2/6.35 = 0.5. Assessment: As d c/δN is greater than 0.1 but less than 0.8, the critical length has to be calculated and the MAOP evaluated. Step 2—Length of corrosion The length of projected corrosion is given in this example. Step 3—Constant Kf As d c/δN is greater than 0.18, calculate the value of the constant Kf from Equation D1 as follows: 2    dc /δ N Kf =    −1   (1.1 d c / δ N ) − 0.15 

1/ 2

  

. . . D6

= 0.74 Step 4—Critical length of corrosion Calculate the value of the critical length (Lc) from Equation D2 as follows:

Lc =1.12Kf (Dδ N )

1/ 2

. . . D7

= 57.65 mm. Step 5— Compare L c with L p Compare the value of the critical length (L c) with the projected length (L p ): millimetres Example: Case 1

Lc

Lp

(a) (b) (c) (d)

57.65 57.65 57.65 57.65

25 100 300 1000

Evaluation of MAOP of corroded pipe In example Case 1(a), where L p is 25 mm, which is less than 57.65 mm (the value of L c), the corroded pipe may be operated without any reduction in the original MAOP established previously for the non-corroded pipe, i.e., p c is equal to po. In examples Case 1(b), (c) and (d), where L p is 100 mm, 300 mm and 1000 mm, all of which are greater than 57.65 mm, the value of L c and a new MAOP (pc) are to be calculated.

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Step 6—Constant K c Calculate the values of the constant Kc, where L p is 100 mm, 300 mm, and 1000 mm, from Equation D3 as follows: millimetres Example: Case 1 (b) (c) (d)

Lp 100 300 1000

Kc 1.28 3.85 12.84

In examples Case 1(b) and (c), the value of K c is less than 4. In example Case 1(d), the value of K c is greater than 4. Step 7—Value of K c less than or equal to 4 Calculate the value of a new MAOP (pc) for values of K c equal to 1.28 and 3.85 from Equation B4 as follows:   1 − 2 d c / 3δ N  p c = 1.1 po  1/ 2  2 1 − 2 /[3 ( + 1 ] ) d K δ c N c  

. . . D8

In example case 1(b), where L p = 100 mm and K c = 1.28, pc = 0.92 pc. In example Case 1(c), where L p = 300 mm and K c = 3.85, pc = 0.80 po. Step 8—Value of K c greater than 4 Calculate the value of a new MAOP (p c) for the value of Kc equal to 12.84 from Equation B5 as follows: p c = 1.1 po (1 − d c / δ N )

. . . D9

In example Case 1(d), where Lp = 1000 mm and K c = 12.84, pc = 0.55 po. Case 2 DEPTH OF CORROSION 0.5 mm Step 1— Depth of corrosion Express the depth of corrosion as a ratio of the nominal wall thickness, i.e. d c/δN = 0.5/6.35 = 0.08. Assessment: As d c/δN is less than 0.1, the MAOP need not be reduced, i.e., pc is equal to po. Step 2—Length of corrosion Step 2 and subsequent steps are unnecessary; however, as a further example, Steps 3 to 8 are shown as follows: Step 3—Constant K f As d c/δN equals 0.08, which is less than 0.18, the value of Kf is 4. Step 4— Critical length of corrosion Calculate the value of the critical length (L c) from Equation D2 as follows: 1/ 2 Lc = 1.12 K f ( D δ N )

. . . D10

= 311.6 mm. Step 5— Compare Lc with L p Compare the value of the critical length (L c) with the projected length (L p ): millimetres Example: Case 2

Lc

Lp

(a) (b) (c) (d)

311.6 311.6 311.6 311.6

25 100 300 1000

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Evaluation of MAOP of corroded pipe In examples Case 2(a), (b) and (c), where L p is 25 mm, 100 mm, and 300 mm, which is less than 311.6 mm (the value of L c), the corroded pipe may be operated without any reduction in the original MAOP established previously for the non-corroded pipe, i.e., pc is equal to p o. In examples Case 2(d), where L p is 1000 mm, which is greater than 311.6 mm (the value of L c), a new MAOP (p c) is to be calculated. Step 6—Constant K c Calculate the value of the constant Kc, where L p is 1000 mm from Equation A3 as follows: K c = 0.893 L p ( D δ N )

−1 / 2

. . . D11

= 12.84. Step 7 — Value of Kc less than or equal to 4 As K c is not greater than 4 this Step is not required. Step 8 — Value of K c greater than 4 Calculate the value of a new MAOP (pc) for a value of Kc equal to 12.84 from Equation D5 as follows: p c = 1.1 po (1 − d c / δ N)

. . . D12

In example Case 2(d), where L p = 1000 mm and K c = 12.84, pc = po; and therefore original MAOP is acceptable.

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AS 2885.3—2001

FIGURE D1 REVIEW PROCEDURE FOR CORRODED PIPE www.standards.com.au

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FIGURE D2 ILLUSTRATION OF NOTATIONS Ls AND dc /δN

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AS 2885.3—2001

FIGURE D3 RELATIONSHIP BETWEEN Kf (BETWEEN THE VALUES 0.448 AND 4) AND THE RATIO dc /δN (BETWEEN THE VALUES 0.18 AND 0.8)

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FIGURE D4 RELATIONSHIP BETWEEN pc AND po IN TERMS OF VALUE OF THE RATIO dc /δN BETWEEN THE VALUES 0.18 AND 0.8 AND THE CONSTANT Kc , WHERE Kc IS EQUAL TO OR LESS THAN 4

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FIGURE D5 RELATIONSHIP TERMS OF VALUE OF THE RATIO dc /δN BETWEEN THE VALUES 0 AND 0.8, WHERE THE CONSTANT Kc IS GREATER THAN 4

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APPENDIX E

TYPICAL PIPELINE MARKERS (Informative)

DIMENSIONS IN MILIMETRES

FIGURE E1 TYPICAL PIPELINE MARKERS © Standards Australia

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