AS 2885-3 Pipelines Gas and Petroleum-Operation & Maint..pdf

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AS 2885.31997

Australian Standard

PipelinesGas and liquidpetroleum

Part 3: Operation and maintenance


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This Australian St andard was prepared by Committee ME/38, P etroleum Pipelines.It was approved on behalf of the Council of S tandards Australia on 2 April 1997and published on 5 May 1997.

The following interests are represented on Committee ME/38:

Alinta Gas, Australia

Australasian Corrosion Association

Australasian Institute of Mining and Metallurgy

Australian Gas Association

Australian Institute for Non-destructive Testing

Australian Institute of Petroleum

Australian Pipeline Industry Association

Bureau of Steel Manufacturers of Australia

Co-operative Research Centre for Materials, Welding and Joining

Department of Energy, N.S.W.

Department of Minerals and Energy, N.S.W.

Department of Minerals and Energy, W.A.

Department of Mines and Energy, Qld.

Department of Mines and Energy, N.T.

Department of Natural Resources and Environment, Vic.

East Australian PipelineEpic Energy Operation and Maintenance, S.A.

Hazardous Industry Planning Taskforce, Australia

Institution of Engineers, Australia

Metal Trades Industry Association of Australia

Mines and Energy, S.A.

Ministry of Commerce, New Zealand

Office of Energy, W.A.

Welding Technology Institute of Australia

Review of Australi an Standards. To keep abreast of progress in industry, Australian Standards aresubject to periodic review and are kept up to date by the issue of amendments or new editions asnecessary. It is important therefore t hat Standards users ensure that they are in possession of t he latestedition, and any amendments thereto.Full details of all Australian Standards and related publications wil l be found in the Standards AustraliaCatalogue of Publications; this information i s supplemented each month by the magazine The

Australian Standard, which subscribing members receive, and which gives detail s of new publicatio ns,new editions and amendments, and of withdrawn Standards.Suggestions for improvements to Australian Standards, addressed to the head office of Standards

Australia, are welcomed. Notificat ion of any inaccuracy or ambiguity found in an Australian Standardshould be m ade wit hout delay i n order that the matter may be investigated and appropriate action taken.

This Standard was issued in draft form for comment as DR 93007.


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AS 2885.31997

Australian Standard

PipelinesGas and liquidpetroleum

Part 3: Operation and maintenance

Originated in part as AS CB28 1972.Previous edition AS 2885 1987.Revised and redesignated in part as AS 2885.3 1997.

PUBLISHED BY S TANDARDS AUSTRALIA(STANDARDS A SSOCIATION OF AUSTRALIA)1 THE CRESCENT, HOMEBUSH, NSW 2140

ISBN 0 7337 1192 8


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AS 2885.3 1997 2

PREFACE

This Standard was prepared by the Joint Standards Australia/Standards New Zealand

Committee ME/38 on Petroleum Pipelines, to supersede AS 2018 1981, SAA LiquidPetroleum Pipeline Code , and AS 28851987, SAA Pipeline Code, as well as the parts ofAS 16971981, SAA Gas Pipeline Code that relate to an MAOP of more than 1050 MPa

or a hoop stress of more than 20%, and revising the operation and maintenance relatedSections 9, 10, 11, 12, 13 and 14 of AS 28851987. The major inclusion is that of

sections of the Australian Institute of Petroleum (AIP) code of practice for inspection and

maintenance of liquid hydrocarbon pipelines (in Victoria) AIP CP18-1991.

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.

The objective of this Standard is to provide minimum requirements for the operation and

maintenance of pipelines complying with AS 2885.1 and 2.

The review of this Standard coincides with a move to deregulation and as such there maybe a need to further review this Standard in the relative short-term future.

This Standard is one of the following series, which refers to high pressure petroleum

pipelines:

AS

2885 Pipelines Gas and liquid petroleum

2885.1 Part 1: Design and construction

2885.2 Part 2: Welding

2885.3 Part 3: Operation and maintenance (this Standard)

Gas pipelines with a pressure of less than 1050 MPa and a hoop stress of less than 20%

are covered by AS 1697.The term normative has been used in this Standard to define the application of the

appendix to which it applies. A normative appendix is an integral part of a Standard.

Copyright STANDARDS AUSTRALIA

Users of Standards are r eminded that copyright subsists in all Standards Australia publications and software. Except where theCopyright Act allows and except where provided for below no publications or software produced by Standards Australia may bereproduced, stored in a retrieval system in any form or t ransmitted by any means without prior permission in writing fromStandards Australia. Permission may be conditional on an appropriate royalty payment. Requests for permission and informationon commercial software royalties should be directed to the head office of Standards Australia.

Standards Australia will permit up to 10 percent of the technical content pages of a Standard to be copied for useexclusively in-house by purchasers of the Standard without payment of a royalty or advice to Standards Australia.

Standards Australia will also permit the inclusion of its copyright material in computer software programs for no r oyaltypayment provided such programs are used exclusively in-house by the creators of the programs.

Care should be taken t o ensure t hat material used is from the current edition of the Standard and that it is updated whenever theStandard is amended or revised. The number and date of the Standard should therefore be clearly identified.

The use of material in print form or in computer software programs t o be used commercially, with or without payment, or incommercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia at any time.


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3 AS 2885.3 1997

CONTENTS

Page

SECTION 1 SCOPE A ND GENERAL

1.1 SC OPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.2 BA SIS O F S TAN DA RD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.4 RISK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.5 REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.6 DE FIN I TI ON S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.7 REC OR DS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SECTION 2 PREPARATION FOR O PERATION

2.1 GE NERA L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.2 PROCEDURES AND PLANS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3 RESPONSIBILITIES FOR PERSONNEL . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.4 READINESS FOR OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.5 DELAYED COMMENCEMENT OF OPERATION . . . . . . . . . . . . . . . . . . . . 7

2.6 FILLING PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

SECTION 3 OPERATING REQUIREMENTS

3.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2 NORMAL OPERATING PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3 SAFETY AND OPERATING PLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4 EMERGENCY PLANS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.5 VENTING PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.6 PURGING PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

SECTION 4 OPERATING CONDITION CHANGES

4.1 DESIGN CONDITION CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.2 PRESSURE TESTING OF DESIGN CONDITION CHANGES . . . . . . . . . . . 19

4.3 PIPELINE MODIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.4 REVIEW OF PRESSURE-CONTROL AND OVER-PRESSURE

PROTECTION SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.5 REVIEW OF DESIGN LIFE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.6 REVIEW OF MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP) 20

4.7 REVIEW OF LOCATION CLASSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.8 TRANSFER OF OWNERSHIP OR OPERATORSHIP OR BOTH . . . . . . . . . . 20

4.9 ABANDONING A PIPELINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.10 RECORDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

SECTION 5 MAINTENANCE REQUIREMENTS

5.1 PIPELINE INTEGRITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

5.2 PIPELINE INSPECTION AND ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . 22

5.3 COATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.4 PIPE WALL DEFECT ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245.5 ANCILLARY EQUIPMENT ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . 26

5.6 CATHODIC PROTECTION CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.7 CATHODIC PROTECTION INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 27


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AS 2885.3 1997 4

Page

5.8 PRESSURE CONTROL AND PROTECTIVE EQUIPMENT INSPECTION . . 27

5.9 PIG TRAP INSPECTION AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . 27

5.10 CASING (SLEEVE) MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.11 STRUCTURES HOUSING EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . 28

SECTION 6 PIPELINE REPAIRS

6.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.2 SUPERVISION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.3 COMMUNICATION AND CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.4 WORKING ON PIPELINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.5 REPAIR STRATEGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

6.6 WELDING ONTO AN IN-SERVICE PIPELINE . . . . . . . . . . . . . . . . . . . . . . 31

6.7 HOT-TAPPING OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

APPENDIX

A LIST OF REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

B ASSESSMENT OF A CORRODED PIPELINE . . . . . . . . . . . . . . . . . . . . . . 36

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46


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5 AS 2885.3 1997

STANDARDS AUSTRALIA

Australian Standard

Pipelines Gas and liquid petroleum

Part 3: Operation and Maintenance

S E C T I O N 1 S C O P E A N D G E N E R A L

1.1 SCOPE This Standard specifies the minimum requirements for the operation and

maintenance of pipelines complying with AS 2885.1 a nd AS 2885.2.

1.2 BASIS OF STANDARD It is not the intention of this Standard to prescribe a

detailed set of operating and maintenance procedures that will encompass all cases. The

operating authority, using its experience and its knowledge of the facilities and conditionsunder which it operates, shall develop operating and maintenance procedures based on the

relevant requirements of the Standard. These procedures shall be adequate with regards tothe safety of the public, operating personnel, pipeline and protection of the environment.

1.3 APPLICATION The requirements of this Standard apply to the operation and

maintenance of pipelines designed in accordance with AS 2885.1.

The requirements of this Standard will also apply to the operation and maintenance of

existing pipelines when they are modified to operate under the conditions within the scopeof this Standard.

This Standard is not intended to be applied retrospectively to existing pipelines that have

not been modified.

1.4 RISK MANAGEMENT Risk management during operation and maintenance

should be addressed in accordance with AS 2885.1.

1.5 REFERENCED DOCUMENTS The documents referred to in this Standard arelisted in Appendix A.

1.6 DEFINITIONS For the purpose of this Standard, the definitions in AS 2885.1

apply.

1.7 RECORDS During the period commencing from the receipt of the materials forthe pipeline and its construction until it is decommissioned or removed, the operating

authority shall prepare and keep current records of the following:

(a) The identity of all materials and components including all test results and inspection

reports.

(b) All maps, charts, plans, drawings and records that are required to allow the

procedures to be properly administered.

(c) Any modifications to the maps, charts, plans, drawings and procedures that arerequired to allow the procedures to be properly administered (e.g. exposure to the

public, changes in design and operating conditions).

(d) Charts and maps showing the location of cathodically-protected pipelines, cathodicprotection equipment and structures affected by or affecting the cathodic protectionsystem.

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(e) The MAOP that are required by Section 4.

(f) The condition of the internal and external surfaces.

(g) Cathodic protection potential readings, cathodic protection unit outputs and

interference current readings.

(h) Details of any corrosion.

(i) Details of any leaks, ruptures and other damage.

(j) A current list of land holders who have been granted easement rights or other

operating permits.

(k) Any approved changes to operating conditions, engineering investigations and any

work carried out i n connection with any changes to operating conditions.

(l) Records of pipeline sections or components identified as potentially high risk in an

emergency.

(m) Routine inspections and inspections carried out when cutting a pipeline or making

hot taps.(n) Repairs and maintenance work to pipelines and stations.

The operating authority shall also prepare and retain for a minimum of 2 years records of

the following:

(i) Necessary operational data.

(ii) Pipeline patrols.

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7 AS 2885.3 1997

S E C T I O N 2 P R E P A R A T I O N F O R O P E R A T I O N

2.1 GENERAL Preparations for operation shall be deemed complete when the

procedures and plans below have been implemented. With the preparation completed andwith approval given to start operation, the filling of the pipeline can occur and the

pipeline can then be put into operation.

2.2 PROCEDURES AND PLANS The operating authority shall ensure that the

following plans and procedures have been prepared and approved as appropriate, and thatpersonnel have been properly trained in their application:

(a) Operating, maintenance and repair procedures.

(b) Safety and operating plans including emergency plans.

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

2.3 RESPONSIBILITIES FOR PERSONNEL Personnel responsible for the operationand 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) aware of properties of the fluid, including its hazard level in accordance withAS 3920.1;

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

(d) capable of arranging for damaged pipelines to be repaired.

2.4 READINESS FOR OPERATION Pipelines shall not be considered ready tocommence operation unless, as a minimum, the following checklist has been completed:

(a) The pipeline complies with the requirements of all relevant parts of AS 2885.

(b) The hydrostatic strength and leak test requirements have been achieved.

(c) The MAOP has been established.

(d) The welds of tie-ins to existing facilities have been inspected by an approved non-

destructive examination method and are considered to comply with AS 2885.2.

(e) Components have been tested for satisfactory operation. Where impractical, otherappropriate inspection shall be carried out.

(f) Operating, maintenance and emergency personnel have been trained.

(g) The pipeline is cathodically protected.

(h) Third party awareness is established in accordance with Clause 3.2.4.

Additional site specific aspects may need to be evaluated prior to commencement of

operation.

NOTE: Initial operation may be approved before completion of t he field work, provided that the

incomplete work does not directly affect the safety of the pipeline, the public or the operating

personnel.

2.5 DELAYED COMMENCEMENT OF OPERATION Where a pipeline is to beplaced in operation with a time delay after it has been hydrostatically tested and if the

fluid is allowed to remain in the pipeline, the test fluid shall be dosed with a corrosion

inhibitor or the pipeline filled with a fluid that inhibits corrosion, unless it can bedemonstrated that such measures are not warranted.

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AS 2885.3 1997 8

If the test fluid is removed, the pipeline shall be dried or purged with inert gas to produce

a moisture level which will not promote corrosion during the delay period.

Where the pipeline is left filled with a liquid, precautions shall be taken to ensure that nodamage is caused by overpressure due, for example, to thermal expansion effects.

During the period between the hydrostatic test and the initial operation, the pipeline shallbe inspected in accordance with Clause 5.7 to determine whether the corrosion mitigationsystems are effective, and shall undergo surveillance in accordance with Clause 3.2.2.

Corrective action shall be taken when an inspection reveals that unacceptable corrosion is

occurring.

2.6 FILLING PROCEDURES

2.6.1 General The operating authority shall ensure that

(a) a pipeline is filled in a safe manner;

(b) work is undertaken on a pipeline only when all relevant aspects of this Standard

have been complied with; and(c) an approved procedure is used.

The filling of pipelines shall take into account the following actions:

(i) Controlling the filling rate.

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

(iii) Limiting the mixing of fluids at their interface.

(iv) Preventing the formation of explosive gaseous mixtures at the gas/air interface.

(v) Removing unacceptable residues from the pipeline.

(vi) Preventing the discharged fluid from causing unacceptable environmental effects

such as damage to crops, excessive erosion, soil contamination or contamination ofwatercourses or bodies of water.

(vii) Allowing any static electricity that may be generated to be continually discharged

by an effective earth.

(viii) Minimization of hydrocarbon discharge.

2.6.2 Filling a gas pipeline Where a gas pipeline which is full of air is to be placed in

operation, the air may be displaced with gas separated with an inert gas slug provided thatan appropriate continuous steady flow is introduced at one end of the pipeline and ventedat the other. The flow should not be interrupted until the vented gas is fr ee from air. The

vent should then be closed.

Where an uninterrupted flow cannot be maintained, the slug of inert gas shall be separatedfrom the air by a pig to prevent the formation of an explosive mixture.

When the pipeline has not been designed to allow pigging, alternative procedures shall bedeveloped.

2.6.3 Filling a liquid petroleum pipeline Where air in a pipeline is to be displaced bya hydrocarbon liquid, a s lug of water between spheres or batching pigs shall separate theair and hydrocarbon liquid.

Where water in a pipeline is to be displaced by a hydrocarbon liquid, a sphere or batchingpig shall separate the water from the hydrocarbon liquid.

The flashpoint of the initial hydrocarbon liquid introduced into a pipeline shall, where

possible, be not less than 61C to prevent the formation of explosive gas/air mixtures.

When the pipeline has not been designed to allow pigging, alternative procedures shall bedeveloped.

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9 AS 2885.3 1997

2.6.4 Filling a high vapour pressure liquid (HVPL) pipeline Where the HVPL

consists of a single hydrocarbon, the pipeline may be filled in the gas phase in accordancewith Clause 2.6.2.

Where the HVPL is a m ixture of hydrocarbons, the pipeline shall be filled first with wateror a suitable low vapour pressure hydrocarbon liquid, and that liquid displaced by the

HVPL. The two liquids should be separated by suitable spheres or pigs. The pressure shall

be maintained at, or above, the bubble point of the HVPL to maintain it in its liquidphase.

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S E C T I O N 3 O P E R A T I N G R E Q U I R E M E N T S

3.1 GENERAL The operating authority, using its experience and its knowledge of the

facilities and conditions under which they are operated, shall develop procedures based onthe relevant requirements of this Standard.

Operating personnel shall be suitably qualified, trained and experienced to accepted

industry standards.

3.2 NORMAL OPERATING PROCEDURES

3.2.1 Operating to 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 w hich it w as designed, constructed, tested, and

approved;

(b) ensure that during normal operation, the operating pressure at any point in thepipeline 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 thermal stress limits used in the

pipeline designs are not exceeded;

(d) have written procedures (controlled document) for the operation and maintenance of

the pipeline in accordance with this Standard; and

(e) operate and maintain the pipeline in compliance with these procedures.

The procedure specified in Clause 3.2.1(d) shall include detailed plans and instructions for

persons responsible for the operation and maintenance of the pipeline during normaloperations and maintenance.

3.2.2 Pipeline surveillance

3.2.2.1 General Pipeline surveillance shall be carried out by the operator to ensure a

pipeline is free from identifiable leaks and to identify any unacceptable risks to thepipeline, particularly unnotified external interference near the pipeline. The type of

surveillance and the frequency required for safe pipeline operation varies and is related tothe consequences of a hazard and the hazard r eduction measures in place, as well as being

dependent upon fac tors which include the following:

(a) Operation of a mandatory One-Call System.

(b) Whether the pipeline is above or below ground.

(c) Other forms of protection against interference.(d) Activities by third parties which could affect the pipeline.

(e) Location in a built-up area.

(f) Location 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 which is not regularly used, a patrol at frequent intervals may be

maintained during use only, provided the line is isolated from sources of pressure whennot in use. An annual patrol is required as a minimum.

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11 AS 2885.3 1997

For a pipeline in regular or continuous use, the type of surveillance shall be by at least

one of the f ollowing, provided the observer can clearly identify the pipeline and observeall the surveillance criteria:

(i) Foot patrols.

(ii) Vehicle patrol.(iii) Aerial patrol.

(iv) Water craft for underwater pipelines.

3.2.2.2 Patrol of route The route shall be patrolled and inspected in an approvedmanner at approved intervals, and whenever it is considered that damage or threats to the

integrity of the pipeline may have occurred or may be expected to occur.

The route shall be accessible to authorized personnel and clear access to valve stationsshall be maintained.

Corrective action shall be initiated immediately a condition requiring such action is

detected.

Particular attention shall be given to drains or ditches that are maintained and cleaned byan independent party.

Surveillance criteria shall include the following:

(a) Variations of 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 impeding construction activity on or near theroute.

(d) Impediments to the access to the route, valve stations, pressure regulator stations,

compressor stations, pump stations, cathodic protection sites, communicationinstallations and the like.

(e) Deteriorating condition, visibility, adequacy and correctness of route markers and

signs installed in accordance with the relevant requirements of AS 2885.1.

(f) Security of sites and evidence of unauthorized entry.

(g) Any other factors affecting the safety and operation of the pipeline.

The person conducting the patrol shall

(i) be issued with written patrolling procedures;

(ii) know the extent of the pipeline easement and the location of the pipeline;

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

(iv) maintain a patrol log.

All surveillance patrol records shall be retained for a minimum period of 2 years.

3.2.2.3 Underwater pipelines The pipeline operator will have measures in place such as

to remain reasonably assured that, for underwater crossing, the depth of cover if thepipeline is buried remains adequate, that scouring has not caused any part of the pipeline

to be unsupported beyond allowable freespan length, and that there is no accumulation ofdebris 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 taken. Additional inspections

shall be made following severe floods or storms which could have affected the integrity ofthe crossing. Corrective action s hould be initiated immediately when inspection reveals anunsafe condition.

3.2.2.4 Tunnels, shafts and valve pits Tunnels and shafts shall be inspected at approvedintervals to confirm

(a) the structural integrity of the tunnel or shaft; and(b) the absence of leaks in the pipeline.

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AS 2885.3 1997 12

Corrective action shall be initiated immediately where the necessity for such action is

revealed. Tunnels and shafts accessible by people may be a confined space whereby entryshall be controlled by the confined space entry procedure and permit.

A valve pit may be a confined space whereby entry shall be controlled by the confinedspace entry procedure and permit. The pit shall be kept free of all matter that in any way

could interfere with the operation of the valve.

3.2.2.5 Valves Valves including mainline valves and the emergency hand-operated

equipment of remotely controlled valves shall be operated at intervals not exceeding 18months.

3.2.3 Stations

3.2.3.1 General Stations for pumps, compressors, meters, mainline valves, pressure-

regulators, odorizers and the like shall comply with the following:

(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 theequipment.

(d) Start up, operating, and shutdown procedures for all equipment shall be establishedand followed. The procedures shall include details of the measures required toensure 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, c orrective action shall be initiated immediately.

(g) The necessary firefighting equipment shall be kept on site and maintained in good

condition.

3.2.3.2 Controls and pressure protection equipment Controls and protection equipment,including regulators, controllers, relief valves, and the safety devices shall be inspectedand tested at regular intervals and serviced, as necessary, to ensure that the equipment is

(a) adequate f rom the standpoint of capacity and reliability of operation; and

(b) set at the required level.

3.2.3.3 Site security When a station is unattended, the site shall be appropriatelysecured.

3.2.3.4 Structure A structure housing equipment containing hydrocarbons, such as

valve/regulator/metre 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.

3.2.4 Third party awareness

3.2.4.1 General Consideration shall be given to inform people and organizations thatmay in any way rely upon the safety of the pipeline detailed as follows:

(a) The appropriate authorities and other relevant bodies shall be informed of thehazardous 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.

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(b) Landowners and other occupiers of land through which the pipeline passes shall be

informed of the methods of recognizing an emergency. They should be suppliedwith 24 h contact telephone numbers of the appropriate responsible persons or

organizations to be notified in the case of emergency.

Warnings should be issued concerning the dangers of interference with the pipeline

and its appurtenances.

(c) Landowners and other occupiers of land through which the pipeline passes shall be

visited by staff of the operating authority at approved intervals, and be provided

with information to ensure that their activities do not endanger the pipeline and itsappurtenances.

To ensure land use planning, development, subdivision and the like does not jeopardizethe integrity of the pipeline and the safety of the public and the environment, it is cr itical

that land use planners, property and service designers, developers, owners and operators,

construction organizations and the general public take into account the presence of thepipeline in their intended activities. Frequent communication with these groups is

recommended.

The operating authority should be advised about any changes in planning, development or

similar near the pipeline, preferably while they are still in the concept stages, so that work

will not interfere with the pipeline or vice versa.

Third party development work may require additional protection to be considered such as

concrete slab cover, increasing the depth or varying the route of the pipeline.

Frequent communication with land use planners, developers, excavators, driller and borers

is required to raise or reinforce the awareness of the presence of a pipeline and theconstraints with respect to the use of the land on and near the pipeline.

Constraints on land use adjacent to the pipeline include maintaining access to the pipeline,prohibition of buildings near the pipeline, restriction on and addition of fill, control of

placement of vegetation, power and telegraph poles, f encing and a gricultural activities.

3.2.4.2 Access to the pipeline In order to maintain the security and safe operation ofthe pipeline, regular patrol of the route is mandatory under pipeline regulations and as a

condition of the pipeline licence.

To meet this requirement, the easement or pipeline route shall be able to be accessed and

traversed by pipeline personnel and authorized contractors at any time without delay,except in weather-induced conditions.

3.2.4.3 Prohibition of buildings near the pipeline Where a pipeline easement exists, nobuilding or structure shall be allowed on the easement without approval.

3.2.4.4 Vegetation on and near the pipeline Unless approved, vegetation is to be

restricted to allow free passage along the pipeline route. Vegetation in the vicinity of thepipeline whose roots may damage the anti-corrosion coating of the pipeline, is notpermitted.

3.2.4.5 Addition of fill on or near the pipeline It is preferred that fill is not added on or

near the pipeline as this increased depth increases the cost of excavation and the poorstability of the fill increases the risk of cave-in during subsequent excavation.

If fill must be added, the depth and quality is to be advised prior to placement foragreement by the operating authority. Any landscaping should be level within the

easement or a minimum of 3 m (but preferably 6 m) either side of the pipeline to permit

excavating equipment t o 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 thenatural soil in that area) and shall not contain ash, salt or chemicals that could have a

deleterious affect on the pipeline.

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3.2.4.6 Power and telegraph poles, fencing and agricultural activities Proposed new or

replacement power and telegraph poles and fencing across or along the easement orpipeline route is to be advised prior to commencement to prevent damage to the pipeline

by pole-hole augers or pole drivers. Holes are only to be dr illed and poles or posts placedafter the exact pipeline location has been marked by the operating authority.

Agricultural activities deeper than 300 mm such as deep ripping and the installation ofdrainage systems are not permitted on the pipeline easement, or when no easement exists,

a minimum of 3 m (but preferably 6 m) each side of the pipeline, without the approval of

the operating authority. Such works adjacent to the pipeline should be advised prior tocommencement to allow marking out the prohibited area.

3.2.5 External interference near pipelines

3.2.5.1 General The f ollowing conditions shall be imposed upon external interference

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. It is theresponsibility of the operating authority to bring the requirement to the attention of

third parties.

(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 inspectedand a work plan specified and approved.

(c) A representative from the operating authority shall be present during machine

excavation which exposes a pipeline, to minimize the risk of pipeline damage.

(d) No mechanical equipment shall be used within 1 m of the pipeline even after the

pipeline location has been proven, except when approved by, and under explicit on-site direction from the operating authoritys inspector. Under no circumstances is

mechanical equipment to be used closer than 0.3 m to the pipeline.

(e) The minimum clearance from a pipeline for any buried structure shall be

(i) 0.3 m between the pipeline and the other equipment, if up to 1.5 m wide; and

(ii) 0.5 m between the pipeline and the other equipment, if greater than 1.5 m

wide.

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.

The minimum clearance for parallel installation shall be such that future

maintenance can be conducted, but shall not be less than 0.5 m.

(f) Any accidental damage to the pipeline coating or steel shall be advised to theoperating authority.

(g) All backfill within 150 mm around the pipeline shall be in accordance withAS 2885.1.

(h) Where boring is to take place under or over a pipeline, methods shall be employed

to ensure that the pipeline or its coating will not be damaged and a separation of atleast 0.3 m between the pipe and bore is maintained.

3.2.5.2 Explosives The use of explosives shall not be permitted within 30 m of the

pipeline without prior approval of the operating authority.

3.2.5.3 One-Call-services Operating authorities shall register their assets with One-Call(or D ial Before You Dig) services, where available, for the benefit of members of the

public seeking the location of buried assets prior to excavation.

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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 buriedassets, at least 48 hours prior to excavating.

3.2.6 Communications systems Adequate communication systems shall be used toensure safe pipeline operation under both normal and emergency conditions. Systems

allowing multiple simultaneous listening are preferred over one-to-one s ystems.

3.2.7 Noise abatement A certain amount of noise is inherent in operation and

maintenance activities. The best practicable methods and industry standards should beemployed to meet statutory requirements for the protection of site personnel and thegeneral 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) Use of acoustically treated power tools, compressors and generators.

(d) The timing of all operations and maintenance activities, which should take into

account the impact on the environment.

3.2.8 Leakage survey and detection Operating authorities shall provide for leakage

detection systems or periodic leakage surveys of the pipeline in its operating andmaintenance plan. The types of surveys selected shall be effective for determining

whether potentially hazardous leakage exists. The extent and frequency of the leakagesurveys shall be determined by the operating pressure, piping age, class location, and

whether the pipeline transports gas without an odorant.

3.2.9 Review of procedures Operating and maintenance procedures, and emergencyplans shall be reviewed periodically and, if necessary, shall be revised and approved.

3.3 SAFETY AND OPERATING PLAN

3.3.1 General A safety and operating plan shall be established, monitored and

maintained by the operating authority. The plan shall detail the policy of protection of

personnel, the public and the environment including measures to

(a) protect the pipeline and associated installations;

(b) promote public awareness of the pipeline;

(c) operate and maintain pipeline safety;

(d) respond to emergencies;

(e) minimize product leakage; and

(f) monitor plans in accordance with Clause 5.1.2.

3.3.2 Safety and operating plan requirements The safety and operating plan shallinclude the following:

(a) A description of the pipeline system operation including suitable maps showing theroute of the pipeline, the location of associated facilities such as compressorstations, SCADA control centres, transmission towers, cathodic protection points,

valve stations, metering points, and launching and receiving stations.

(b) An analysis of the likely hazards which include

(i) a systematic identification of hazardous events, their potential causes, andthe consequences (in qualitative terms) of such events; and

(ii) the proposed operational, maintenance and organization safeguards that

would prevent such hazardous event from occurring or should they occur,that would protect the plant, its equipment, operating personnel, thecommunity and the environment.

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AS 2885.3 1997 16

(c) Operational and maintenance safeguards which include

(i) maintenance schedule;

(ii) pipeline inspections; and

(iii) cathodic protection surveys.

(d) Emergency plans covering

(i) impact events;

(ii) fire;

(iii) explosion;

(iv) leak/spill; and

(v) natural events.

3.4 EMERGENCY PLANS The following recommendations are given as a generalguide with respect to emergency plans:

(a) Both operative and supervisory staff levels should be adequate at all times torespond to reported escapes. Procedures should be established in order to ensure that

personnel attend the site of the emergency as soon as possible in the circumstances.An up-to-date contact list of such personnel should be maintained.

(b) Emergency procedures should be established and all operational personnel should bemade aware of them and be fully trained in their application including any action

required from them under such procedures.

(c) Necessary planning and preparation to implement emergency actions to be followedin the event of an accident, a failure or other emergency should be made, and may

include the following:

(i) Promptly and expediently providing remedial action for the safety of thepublic and operating personnel, minimizing damage to property and

protecting the environment.

(ii) Liaising with the appropriate authorities 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 the actions and revising them at approved intervals.

(vii) Revising the actions whenever there is a change in the fluid, the operating

conditions along the route or the equipment.

(viii) Carrying out periodic mock-up exercises to determine the procedural

correctness and personnel understanding of the emergency procedures.

(ix) Having emergency equipment, pipe and fittings in good working order.

(d) Emergency plans should consider the necessity of the following:

(i) Attendance at the emergency site to assess the situation.

(ii) Reduction of the pressure in the pipeline.

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(iii) Closure of any valves on each side of any dangerous or potentially dangerous

situation.

(iv) Establishment of a control centre from which emergency activities may be

coordinated.

(v) Instruction to the appropriate authorities and other relevant bodies of theaction to be taken.

(vi) Evacuation of any endangered members of the public and unauthorized

personnel.

(vii) Prohibition of any road and rail traffic, low-flying aircraft and isolation ofelectrical power, in any areas that may be hazardous to safety, to reduce any

risk of ignition and resultant dangers.

(viii) Expeditious transport of repair equipment, materials and personnel to the

site.

(ix) Additional prudent action that particular circumstances may make necessary.

3.5 VENTING PROCEDURES

3.5.1 Precautions to prevent an explosion Precautions shall be taken to prevent theaccidental 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 theproposed 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

(i) smoking and the presence of matches, lighters, and naked flame; and

(ii) all sources of ignition from the work area, e.g. spark-ignition engines, motor

vehicles and mobile phones.

(g) Electrical safety (see AS 2885.1)3.5.2 Venting gas In cases where venting of gas is to take place, reference should be

made to the Recommendations IGE/SR/23 and the guidance contained therein should be

applied as appropriate.

3.6 PURGING PROCEDURES

3.6.1 General Hydrocarbon fluids shall be purged from a pipeline when operating

procedures dictate the need and before a pipeline is abandoned. Any purging of pipelinesshall be in accordance with an approved procedure.

3.6.2 Gas When a pipeline is to be purged of gas after depressurization

(a) a continuous steady flow of air shall be introduced at one end of the pipeline andvented at the other end, until the vented fluid is free of gas; or

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AS 2885.3 1997 18

(b) a slug of inert gas such as nitrogen or carbon dioxide shall be introduced between

the air and the gas, to prevent the formation of an explosive mixture at theinterface; or

(c) the requirements of AGA 1975 shall be met.

Dissimilar fluids should be separated by suitable spheres or batching pigs.Discharged gas shall be disposed of in an approved manner.

3.6.3 Hydrocarbon liquid Where a pipeline is to be purged of hydrocarbon liquid, the

purging fluid shall be water, air or a non-flammable gas.

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

introduced between the air and the hydrocarbon liquid.

Where the hydrocarbon has a flashpoint greater than 61C and is being purged with air, a

batching sphere or a batching pig should be introduced between the air and thehydrocarbon liquid.

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

pigs.

3.6.4 Purging an HVPL Where an HVPL is to be purged from a pipeline the pressurein the pipeline shall be maintained at a value greater than the bubble point at all points in

the pipeline until the purging is compete. The liquid phase purging operation shall be inaccordance with Clause 3.6.3.

Gas phase purging shall be used only where the pr essure in the pipeline has accidentally

fallen to less than the bubble point or where the HVPL is deemed to be a singlehydrocarbon. The gas phase purging operation shall be in accordance with Clause 3.6.2.

Dual-phase conditions shall be avoided.3.6.5 Trapped hydrocarbon Where a pipeline or auxiliary equipment that has been in

service is to be filled with air and there is a r easonable possibility that the inside surfacesare wetted with a volatile combustible liquid or a volatile combustible liquid may have

accumulated in low places, a procedure designed to purge such liquids shall be used.

NOTE: Transmission pressure may be trapped in valve body cavities and other blind off-takes.

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S E C T I O N 4 O P E R A T I N G C O N D I T I O NC H A N G E S

4.1 DESIGN CONDITION CHANGES The operating authority shall ensure thatwhere 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 m odification 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 would 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.

(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 inaccordance with AS 2885.1.

(iv) The protection measures r equired against third-party damage in accordance with

AS 2885.1.

(v) The physical characteristics of the pipeline, including the diameter, w all 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.

4.2 PRESSURE TESTING OF DESIGN CONDITION CHANGES Where a change

in a design condition occurs, and where a pipeline which has been strength-pressure testedpreviously to an appropriate pressure is in good physical condition, the results of that

strength test shall be used to determine the MAOP.

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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 inaccordance with AS 2885.1 and the results to that pressure test used to determine the

MAOP. The condition of the pipeline shall be determined through a f ormal engineeringinvestigation.

4.3 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 orthe inclusion of a pressure-containing component) the MAOP of the modified pipeline

shall be determined in accordance with AS 2885.1, and approved.

4.4 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 protectionsystems shall be approved.

Suitability of systems shall be reviewed at approved intervals and in conjunction withchanges to supply capacity.

4.5 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 shallbe made of the design, operating conditions and history of the pipeline, and an

engineering investigation shall be made to determine its condition and any limits forcontinued safe operation. The pipeline shall only be operated under the conditions and the

limits so established and approved.

4.6 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 integrityof 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 accordancewith Appendix B.

4.7 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 theclassification of a location, the classification of the locations along the route of the

pipeline shall be reviewed and if necessary changed, and appropriate corrective actionshall be taken.

4.8 TRANSFER OF OWNERSHIP OR OPERATORSHIP OR BOTH The new

owners or operators or both shall satisfy themselves of the integrity of the pipeline priorto takeover, by examination of the previous owner s or operator s records or by

conducting an assessment of i ntegrity.

4.9 ABANDONING A PIPELINE When a pipeline is abandoned, it shall bedisconnected from all sources of hydrocarbons that may be present in other pipelines,

meter stations, control lines and other appurtenances, and shall be purged of hydrocarbonsand vapour with a non-flammable fluid. Disposal of the purging fluid shall meet all

relevant environmental and safety requirements.

When abandonment in place is approved, the ends of the pipeline shall be sealed on

completion of purging and any warning signs along the route shall be removed.

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Consideration is to be given to filling the pipeline with a cementitious slurry, or

alternatively applying cathodic protection to prevent the eventual collapse of the pipelineand consequent ground subsidence.

In the event that cathodic protection is applied, the responsibility for ownership willremain with the pipeline operator and appropriate records will be kept.

4.10 RECORDS A record of approved changes of operating conditions, all engineering

investigations and work carried out in connection with any change in the operatingconditions shall be maintained until the pipeline is abandoned or removed.

A record should be kept of all abandoned pipelines that remain in situ, to prevent possiblemistakes in identifying an abandoned pipeline as an operational pipeline.

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S E C T I O N 5 M A I N T E N A N C E R E Q U I R E M E N T S

5.1 PIPELINE INTEGRITY

5.1.1 General For the purpose of integrity assessment, the MAOP of a pipeline isequivalent to the allowable maximum pipeline pressure under the requirements ofAS 2885.1.

In order to maintain the integrity, a pipeline shall have 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

defects or uniform general wall thickness loss, the minimum wall thicknessshall be calculated in accordance with AS 2885.1.

(ii) For a pipeline with physical damage, the minimum wall thickness shall beassessed in accordance with Clause 5.4.1 or other approved method.

(iii) For a pipeline with corrosion defects, the minimum wall thickness shall beassessed in conformance with Clause 5.4.2 or another approved method.

(b) Sufficient integrity at joints to prevent leakage at the design conditions and at theMAOP.

(c) An appropriate pressure control system to ensure that the pipeline pressure does not

exceed the MAOP during normal operation.

(d) A documented system for pipeline maintenance and corrosion prevention.

5.1.2 Monitoring plan As part of the safety and operating plan (as required in

Clause 3.3), the operating authority shall prepare, document and follow a plan detailingthe inspections and tests that are necessary to allow the quality and integrity of completed

pipelines to be monitored, to ensure that they continue to comply with the engineering

design.

5.1.3 Audit A operating authority shall periodically conduct a full audit and

assessment of each pipeline to

(a) assess the integrity of the pipeline;

(b) review the operational and maintenance procedures of the pipeline; and

(c) implement, if necessary, appropriate measures to ensure continuing pipelineintegrity.

Inspections shall be carried out to identify actual or potential problems that could affectthe integrity of the pipeline. The operator shall plan and perform any maintenance

required to rectify any such problems.

Inspections shall be carried out by appropriately qualified and experienced personnel.

5.2 PIPELINE INSPECTION AND ASSESSMENT

5.2.1 General 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. This includescathodic protection systems, pipeline coatings, surge protection systems, static earth

systems, and inhibitor dosing f acilities.NOTE: Where available, intelligent pigging results should also be considered in assessing

pipeline integrity.

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5.2.2 Regularity of assessment The regularity of assessment should be based on the

past reliability of the pipeline, current knowledge of its condition, the rate of deterioration(corrosion rates, coating degradation and the like), a nd statutory requirements.

5.2.3 Assessment results and appropriate action If the integrity of a pipeline isassessed as being inadequate or at immediate risk, the operator shall immediately take

steps to rectify the problem until the integrity of the pipeline is restored.

Measures shall be taken to mitigate the risk of a leak to the minimum. This may be by a

reduction in pressure, bypassing, or carrying out temporary repairs and appropriately

adjusted surveillance.

5.2.4 Internal surfaces Where a part of any pipeline is removed f or any reason, the

internal surface shall be inspected to confirm integrity, (such as corrosion) withappropriate action taken.

5.2.5 External surfaces

5.2.5.1 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 of

not more than 12 months, and the rate of corrosion shall be assessed. Where the rate ofcorrosion will reduce the design life, remedial action shall be taken.

NOTE: Suitable action may include a reduction of the design life.

5.2.5.2 Buried and submerged uncoated pipelines Uncoated pipelines that are buried or

submerged shall be surveyed using approved techniques at intervals of not more than sixmonths. Pipelines shall be inspected at positions that are not more than 1 km apart and

wherever the most corrosion is expected to occur.

5.2.5.3 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 forcorrosion and evidence of damage to or deterioration of any anti-corrosion coatings.

Cathodic protection systems on coated buried pipelines shall be inspected in accordancewith Clauses 5.6 and 5.7.

The effectiveness of the cathodic protection system on submerged coated pipelines shall

be established within a period of not more than 12 months after installation.

The system shall be monitored at intervals of not more than five years. The interval m ayneed to be shortened towards the end of the design life.

5.3 COATINGS

5.3.1 Above-ground pipework The coating of above-ground pipework should berepaired or renewed if external corrosion is occurring, which will compromise the

integrity of the pipework within the period between integrity assessments. The coatingshould be assessed in particular at crevice areas like pipe supports and on the underside ofthe pipework. The pipe wall should also be inspected for corrosion at areas of blistered or

disbonded coating.

Insulation where installed 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.

NOTE: Corrosion under 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.

Records of the coating condition shall be kept.

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AS 2885.3 1997 24

5.3.2 Below-ground pipework All below-ground pipework should be coated to prevent

external corrosion and be cathodically protected. The coating system used shall beappropriate for underground service and the operating conditions. The coating shall be

applied in conformance with the appropriate industry standards including proper pipesurface preparation, controlled application and quality te sting of the final coating.

The coating shall be maintained to a standard such that

(a) the cathodic protection system effectively maintains protection at all coating

holidays; and

(b) coating disbondment is minimized.

Assessment of the coating condition on below-ground pipework should be achieved by

evaluation of some or all of the following:

(i) Cathodic protection data.

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

(iii) Visual inspection at selected locations of bellhole excavations and where the

pipeline is exposed for other reasons.

Records of the coating condition shall be kept.

5.4 PIPE WALL DEFECT ASSESSMENT

5.4.1 Damaged pipework Unless detailed analysis has been carried out to confirm theacceptability of the defect, defects in excess of the following criteria shall be removed,

replaced or otherwise repaired:

(a) Dents, as described in AS 2885.1 except that maximum depth shall be 6% of the

pipe diameter.

(b) Gouges, grooves and notches which are outside the criteria described in AS 2885.1.

Pipework with wall thickness loss due to grinding should be treated as corroded pipework.

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 MAOPshall 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 withClause 5.4.3 and if necessary a new MAOP established or the corroded portion of the

pipeline repaired or replaced.

Corroded pipelines shall be protected against further corrosion in accordance withAS 2885.1.

NOTE: F igure 5.1 provides a flow chart for assessing corrosion defects.

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 should be maintained or reduced to asafe level (usually 80% of normal operating pressure), until such time as the corroded

area has been cleaned and inspected, the extent and depth of corrosion has beendetermined and an assessment has been made of the corroded portion of the pipeline.

Where the contents of the pipeline are liquid and locked in between valves, c onsideration

shall be given to any increase in pressure that may be caused by changes in temperature.

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NOTES:

1 The design pressure Pd shall be calculated as follows:

where

Pd = design pressure, i n megapascals

Fd = design factor

dp = w all thickness for design internal pressure, in millimetres

y = yield stress, in megapascals

D = nominal outside diameter, in millimetres

2 Test pressure = 1.25 P d

FIGURE 5.1 FLOWCHART FOR ASSESSING CORROSION DEFECTS

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AS 2885.3 1997 26

5.4.3 Assessment of corroded pipework

5.4.3.1 General The assessment required by Clause 5.4.2 shall be made by one of the

following methods:

(a) Pressure testing, in accordance with Clause 5.4.3.2.

(b) Calculation, in accordance with Appendix B, Paragraph B3.

(c) AGA Project PR3-805.

NOTE: This program is based on the calculation method given in Appendix B, Paragraph B3

but is slightly less conservative.

(d) Any other approved methods.

5.4.3.2 Assessment by pressure testing The section of any pipeline containing corrosion

shall be pressure tested in accordance with AS 2885.1 and its MAOP determined in

accordance with Appendix B, Paragraph B2.

The normal maximum pressure, recorded or determined for the corroded section over thesix months prior to the discovery of the corrosion, may be deemed to be a test pressure

for the purposes of r ecalculating the MAOP in accordance with this Clause.

Where the original design included an allowance G (refer to AS 2885.1) and it can beshown that the original allowance is not required for the corroded section of pipe, a

revised value f or G may be used in the re calculation of MAOP. The r evised value shallbe approved.

5.5 ANCILLARY EQUIPMENT ASSESSMENT

5.5.1 General In addition to the pipeline itself, equipment ancillary to the pipeline,

and in particular the items listed in this Clause 5.5, shall be regularly maintained.

5.5.2 Valves Valves require regular usage and maintenance to ensure they are

functioning correctly. They s hould be inspected at approved intervals to ensure that

(a) each valve is properly supported and that corrosion problems at support points arenot 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 are fully operable.

5.5.3 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 thatpoint. Where applicable the interface between the carrier pipe and the pipe support shallbe inspected for corrosion.

5.5.4 Ground entry locations Severe corrosion can occur at the point where pipelinesenter and leave the ground. Such points shall be regularly inspected for coating

deterioration and associated corrosion. The inspection intervals are dependent on thecoating type applied to the line.

5.6 CATHODIC PROTECTION CRITERIA

5.6.1 General For pipeline cathodic protection criteria, including the effects of pipeand soil potentials, foreign structure interference, stray current and telluric effects, the

requirements of AS 2832.1, local pipeline regulations and local electrolysis committeesshall apply.

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5.6.2 Steel-cased crossings Where possible, steel casings shall be maintained

electrically isolated from the pipeline.

If electrical isolation is lost, it shall be restored or other measures taken to prevent

corrosion occurring on the pipe inside the casing.

5.7 CATHODIC PROTECTION INSPECTION

5.7.1 Inspectors The parties responsible for the survey, inspection, testing andmaintenance of the cathodic protection system shall have the requisite experience and

qualifications in c athodic protection as approved by the operating a uthority.

5.7.2 Measuring equipment Only approved measuring equipment shall be used forcathodic protection testing.

5.7.3 Inspections The operating authority shall carry out inspections to ensure the

correct operation of transformer and rectifier units, stray current control and drainagebonds at an interval not exceeding two months in accordance with AS 2832.1.

The operating authority shall, at intervals not exceeding twelve months, carry out cathodicprotection inspections, including pipeline potential surveys in accordance with AS 2885.1

and tests for stray current electrolysis.

The inspections shall ensure that the cathodic protection system is operating satisfactorily

in conformance with the design criteria and Clause 5.6. If variations are f ound, actionshall be taken to rectify the deficiencies.

5.7.4 Records Information should be recorded in accordance with AS 2832.1, to cover

the following major areas:

(a) Commissioning and installation.

(b) Inspections undertaken and results of pipe to soil potential testing.

(c) Equipment maintenance.

5.8 PRESSURE CONTROL AND PROTECTIVE EQUIPMENT INSPECTION All

pressure control and protective equipment shall be subjected to systematic inspection andtesting to determine if they are

(a) in good electrical, mechanical or hydraulic condition;

(b) set to function at the correct pressure;

(c) properly installed and protected from foreign material or other conditions that mightprevent proper operation;

(d) installed in a manner so as to prevent unauthorized operation or alteration; and

(e) operating correctly.

5. 9 PIG TR AP I NS PEC TIO N AN D M AI NT ENA N CE 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, for temporary or removable pig traps, the traps should be inspected before use

for mechanical damage ( due to handling) and for evidence of corrosion.

5.10 CASING (SLEEVE) MAINTENANCE Schedules for pipeline maintenanceshould include appropriate checks on casings and attachments (e.g. checks for pipe to

casing contacts or resistive bonds and sniffing of annulus vents for hydrocarbon).

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AS 2885.3 1997 28

5.11 STRUCTURES HOUSING EQUIPMENT A structure housing equipment shall

be inspected at intervals of not more than 3 months, and shall be maintained in goodcondition.

The inspection shall include the testing of the atmosphere in the structure for toxic andcombustible 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 can result from unexpected loads on the cover.

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S E C T I O N 6 P I P E L I N E R E P A I R S

6.1 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 pressurereduced to a safe level until such time as a repair is effected.

6.2 SUPERVISION Before any work is carried out on a pipeline, the area shall bedeclared safe by a competent person in accordance with Clause 6.4. The person

responsible for declaring the area safe or an equally competent stand-in shall remainalongside workers in that area until all work of a hazardous nature has been completed.

6.3 COMMUNICATION AND CONTROL A reliable communication system and

procedure shall be established between the work site and all locations from which pipelineconditions can be controlled.

6.4 WORKING ON PIPELINES

6.4.1 General When any work is to be carried out on a pipeline, the formation ofmixtures of flammable vapour or gas and air shall be prevented. 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.

The area should be tested continuously to prove the absence of hazardous concentrations

of flammable vapour or gas. The person responsible for declaring the area safe shallremain alongside workers in that area until all work of a hazardous nature is completed.

6.4.2 Tunnels, shafts, and casing The atmosphere in a tunnel, shaft, or casing,

including those which 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.

6.4.3 Precautions to prevent an explosion To prevent an accidental ignition ofpossible hazardous concentrations of flammable vapour or gas, appropriate precautions

shall be taken and, where relevant, the following requirements shall apply:

(a) The work area shall be monitored, using approved and correctly calibrated andtested flammable gas detectors prior to and during the work, to determine the

presence a nd concentration of flammable gas.

(b) Work shall be suspended whenever a flammable gas concentration within theexplosive range is detected.

(c) The perimeter of hazardous areas shall be determined and delineated.

(d) Suitable signs to indicate to the public the extent of any hazardous areas shall be

displayed.

(e) The following shall be prohibited in hazardous areas:

(i ) Sm oking.

(ii) The presence of matches, lighters and naked flame.

(iii) The access of any sources of ignition to the work area (e.g. spark-ignition

engines, motor vehicles a nd mobile phones).

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AS 2885.3 1997 30

(f) Electrical equipment, including radios, flashlights and hand lanterns, shall be safe

for use in Zone 1 hazardous locations as defined by AS 2430.1.

(g) Adequate training and instruction shall be given to operating and maintenancepersonnel about the possibility of e lectric surges (sparks) occurring across insulated

joints.

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

(j) Where two joining flanges are to be separated, an electrical connection shall beinstalled across the proposed separation.

(k) Prior to making a cut in a pipeline the pipeline shall 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.

6.4.4 Pipelines filled with hydrocarbon gas

6.4.4.1 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 fittedcanvas 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

workmen.

6.4.4.2 Where gas is not escaping Work to be carried out on a pipeline containing gasfrom which gas is not escaping shall be in accordance with Clause 6.7.

6.4.5 Pipelines filled with liquid petroleum or HVPL Any cutting of pipelines that

contain or have contained liquid petroleum or HVPL that has not been purged shall onlybe cut by non-sparking mechanical means and any heat generated shall be controlledbelow the product flashpoint.

Welding shall not be carried out on a pipeline filled with liquid petroleum or HVPL,

unless liquid and vapour is prevented from escaping from the pipeline.

6.4.6 Purged pipelines Where a pipeline has been purged in accordance withSection 3, 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 bepermitted unless the flow of hydrocarbon fluid toward the work site is prevented and thepipeline 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 operationof 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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31 AS 2885.3 1997

6.5 REPAIR STRATEGY

6.5.1 Initial response Immediately a leak is detected, corrective action shall beinitiated. Damage should be evaluated pr omptly.

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 r educed to a safe level,until necessary repairs have been completed and inspected and it is safe to resume normaloperation.

6.5.2 Repair strategy flowchart The operating authority shall plan a repair strategy

taking into account the process shown in Figure 6.1.

6.5.3 Temporary repairs Temporary repairs shall exclude any method which involves

welding. Temporary repairs may only be made when immediate shut down is notpracticable, provided that as soon as possible they will be made permanent in accordance

with Clause 6.5.4.

6.5.4 Permanent repairs Permanent repairs shall be made to a pipeline, subject to thefollowing conditions:

(a) On a liquids pipeline, the defect has been sealed 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 6.2 to 6.4.

(e) Cutting and welding comply with Clauses 6.6 and AS 2885.2. Welding proceduresshall 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 shall be pre-tested and have a wall thickness and a SMYS of notless than that of the replaced section. The repaired section shall not impede the

passage of the type of pig for which the pipeline was designed.

(g) Pressure-containing full-encirclement welded split sleeves and other approved

mechanical devices that are used to effect repairs shall have design pressuresdetermined in accordance with AS 2885.1, subject to the MAOP of the pipeline not

being reduced.

(h) The carbon equivalent for materials which are to be welded into the pipeline shallconform 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.

6.6 WELDING ONTO AN IN-SERVICE PIPELINE

6.6.1 General Welding onto an in-service pipeline shall be in accordance with the

relevant requirements of AS 2885.2.

6.6.2 Monitoring of operating conditions Whilst any welding is in progress, thepressure and flowrate of the fluid shall be monitored continuously. Welding shall be

discontinued at any time when the pressure or the flowrate is outside the limits specifiedin the approved procedure.

6.6.3 Resumption of normal operation The pressure in a pipeline f ollowing 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 tobe resumed.

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AS 2885.3 1997 32

FIGURE 6.1 REPAIR STRATEGY FLOWCHART

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33 AS 2885.3 1997

6.7 HOT-TAPPING OPERATIONS

6.7.1 General A hot-tapping operation shall be carried out by trained and experiencedpersons and in accordance with an approved written procedure which incorporates the

appropr

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