COMMITTEE ME-038
DR 04561 (Project ID: 2425)
Draft for Public Comment Australian Standard LIABLE TO ALTERATION—DO NOT USE AS A STANDARD BEGINNING DATE FOR COMMENT:
17 December 2004
CLOSING DATE FOR COMMENT:
18 February 2005
Pipelines—Gas and liquid petroleum Part 1: Design and construction
COPYRIGHT
Draft for Public Comment Australian Standard The committee responsible for the issue of this draft comprised representatives of organizations interested in the subject matter of the proposed Standard. These organizations are listed on the inside back cover. Comments are invited on the technical content, wording and general arrangement of the draft. The preferred method for submission of comment is to download the MS Word comment form found at http://www.standards.com.au/Catalogue/misc/Public%20Comment%20Form.doc. This form also includes instructions and examples of comment submission. When completing the comment form ensure that the number of this draft, your name and organization (if applicable) is recorded. Please place relevant clause numbers beside each comment. Editorial matters (i.e. spelling, punctuation, grammar etc.) will be corrected before final publication. The coordination of the requirements of this draft with those of any related Standards is of particular importance and you are invited to point out any areas where this may be necessary. Please provide supporting reasons and suggested wording for each comment. Where you consider that specific content is too simplistic, too complex or too detailed please provide an alternative. If the draft is acceptable without change, an acknowledgment to this effect would be appreciated. When completed, this form should be returned to the Projects Manager, Kris Longmore via email to
[email protected]. Normally no acknowledgment of comment is sent. All comments received electronically by the due date will be put before the relevant drafting committee. Because Standards committees operate electronically we cannot guarantee that comments submitted in hard copy will be considered along with those submitted electronically. Where appropriate, changes will be incorporated before the Standard is formally approved. If you know of other persons or organizations that may wish to comment on this draft Standard, could you please advise them of its availability. Further copies of the draft are available from the Customer Service Centre listed below and from our website at http://www.standards.com.au/.
STANDARDS AUSTRALIA Customer Service Centre Telephone: 1300 65 46 46 Facsimile: 1300 65 49 49
mailto:
[email protected] Internet: http://www.standards.com.au/
e-mail:
Draft for Public Comment STANDARDS AUSTRALIA Committee ME-038—Petroleum Pipelines Subcommittee ME-038-01 — Design and Construction DRAFT Australian Standard Pipelines—Gas and liquid petroleum Part 1: Design and construction (To be AS 2885.1)
This Standard specifies requirements for the design and construction of carbon and carbon manganese steel pipelines and associated piping and components that are used to transmit single and multiphase hydrocarbon fluids. Major changes proposed in this draft relate to a structural basis for increasing the maximum allowable operating pressure of a qualifying existing pipeline. These benefits are supported by robust requirements for safety, structural design, construction, testing and record keeping. Comment on the draft is invited from people and organizations concerned with this subject. It would be appreciated if those submitting comment would follow the guidelines given on the inside front cover. This document is a draft Australian Standard only and is liable to alteration in the light of comment received. It is not to be regarded as an Australian Standard until finally issued as such by Standards Australia.
2
DRAFT ONLY
DRAFT ONLY
PREFACE This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee ME-038 on Petroleum Pipelines, to supersede AS 2885—1997, Pipeline—Gas and liquid petroleum. AS 1697, Gas transmission and distribution systems is currently undergoing revision and will be published as a distribution pipeline standard, and has been deleted as a reference standard. 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 requirements for the design and construction of steel pipelines and associated piping and components that are used to transmit single phase and multiphase hydrocarbon fluids. This standard provides guidelines for use of pipe manufactured from certain non steel or corrosion resistant materials. This Standard is one of the following series, which refers to high pressure petroleum pipelines: AS 2885 2885.0 2885.1 2885.2 2885.3 2885.4 2885.5
Pipelines—Gas and liquid petroleum Part 0: General Requirements Part 1: Design and construction (this Standard) Part 2: Welding Part 3: Operation and Maintenance Part 4: Submarine pipelines Part 5 Field Pressure Testing
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. Statements expressed in mandatory terms in notes to tables and figures are deemed to be requirements of the Standard. This comprehensive revision is the result of extensive work by subcommittee ME-038-1 in response to a request from the industry that it consider increasing the design factor from 0.72 to 0.80. This request prompted a detailed review of each section and each clause of the Standard, resulting in the preparation of some 70 Issue Papers that considered the underlying technical issues (in relation to an increased design factor) and recommended changes to the Standard. These issue papers were debated within the subcommittee and published on the Industry web site to allow consideration by the Industry. The results of these deliberations form the basis of this revision. The revision also reflects the results of a significant and ongoing industry funded research program undertaken by the Australian Pipeline Industry Association and its research contractors, and through its association with the Pipeline Research Council International and the European Pipeline Research Group. This revision provides a basis for Industry to benefit through the application of an increased factor for pressure design (for new pipelines) and a structured basis for increasing the MAOP of a qualifying existing pipeline. These benefits are supported by robust requirements for safety, structural design, construction, testing and record keeping. Significant changes in this Revision include: 1) A restructure of the sections of the document to separate Pipeline General, Pipeline, Stations, and Instrumentation and Control.
DR04561.doc
3
DRAFT ONLY
DRAFT ONLY
2) The separation of information common to Parts 1, 2 3 and 5 of the Standard to a new part (Part 0), including the requirements for a holistic approach to pipeline and environmental safety, and including definitions that apply to the Standard. 3) The incorporation of a section defining the minimum requirements for a pipeline whose maximum allowable operating pressure is proposed to be raised. 4) Section 2 (Safety) is re-written, reflecting experience gained in the seven years since it was revised to provide a mandatory requirement for risk assessment. This revision (2005) provides more explicit guidance on obligation to undertake safety assessments with the integrity required for compliance with this Standard. 5) Section 3 (Materials) is revised to better address the treatment of materials used in pipelines. It includes a requirement to de-rate the specified minimum yield stress of pipe designed for operation at temperatures of 65°C and higher. The use of fibreglass and corrosion resistant alloy pipe materials for pipelines constructed to this Standard is permitted and limited, in this Section. 6) Section 4 (Pipeline General) contains most of the material in the Pipeline General section of the 1997 revision. The Section has been expanded to include: i.
A mandatory requirement for the design of a pipeline for the existing and intended land use.
ii.
A revision of the requirements for effective pipeline marking including a change to require the marker sign to comply with a Danger sign in accordance with AS 1319.
iii. A Plan for Isolation of a Pipeline. iv. Special requirements for pipelines constructed in locations where the consequence of failure by rupture is not acceptable. Provisions for compliance with these requirements for pipelines constructed to this, or to an earlier revision of the Standard in land where the location classification has changed to residential (or equal) is included. v.
The location classification definitions are revised and additional subclasses are defined.
vi. The hydrostatic strength test pressure is re-defined to address the situation where the pipe wall thickness exceeds the pressure design thickness, including corrosion allowance). vii. Provisions for low temperature excursions. viii. Calculation methods for critical defect length, energy release rate and radiation contour 7) The requirements for Fracture Control have been extensively revised to clarify the requirements and to reflect experience gained since 1997. Emphasis is placed on the use of the Battelle Two Curve model given the fact that most gas pipelines in Australia transport “rich” gas. 8) Section 5 (Pipeline) has been revised to incorporate those provisions specific to pipeline in the 1997 revision. Significant changes in this section include: i.
The pipe wall thickness is now required to be the greater of the pressure design thickness, and the thickness required for each other identified load condition.
ii.
An equation for calculating the thickness required for external pressure is provided.
DR04561.doc
4
DRAFT ONLY
DRAFT ONLY
iii. Recognising the result of a comprehensive investigation of its purpose and the impact of a change, the design factor has been changed from 0.72 to 0.80, and the design factor for pipeline assemblies and pipelines on bridges has been changed from 0.60 to 0.67. iv. A mandatory calculation method for determining resistance to penetration by excavator is provided. v.
Requirements for Stress and Strain are completely re-written to clarify the requirements. The limits for each stress condition are tabulated and normative and informative appendices are provided incorporating the relevant equations.
vi. The requirements for a “prequalified” design are included in a new clause. This is permitted to be used for short pipelines DN200 and smaller with a MAOP of 10.2 MPa or less. vii. The provisions for reduced cover for a pipeline constructed through “rock” are revised. 9) Section 6 (Stations) incorporates the provisions of Clause 4.4 of the 1997 revision in relation to Stations. The section has been expanded to require the design basis for stations to be documented. Additional guidance is provided on treatment of lightning, together with some clarifying revisions to the text. 10) Section 7 (Instrumentation and Control) incorporates these requirements that were included in Section 4.2 of the 1997 revision. The requirements for pipeline operation under transient conditions and a tolerance specification for pressure controls on pipelines intended to be operated at MAOP are addressed. 11) Section 8 (Corrosion) incorporates the requirements of Section 5 of the 1997 revision. The section incorporates clarifying revisions. 12) Section 9 (MAOP Upgrade). This is a new section that sets down the minimum process including activities required to demonstrate the fitness of a pipeline to designed and operated at one pressure as suitable for approval for operation at a higher pressure. The section establishes a structured methodology for demonstrating the pipeline fitness and once approved, for commissioning the pipeline at the new pressure. The maximum pressure is limited to the hydrostatic strength test pressure divided by the equivalent test pressure factor. 13) Section 10 (Construction). This section incorporates Section 6 of the 1997 standard. The requirements for construction survey are clarified, and a minimum accuracy for as-constructed survey are incorporated. Since padding and backfilling are two activities that impact on the pipeline integrity, the 2005 revision incorporates additional requirements for these activities reflecting outcomes from APIA research on backfilling. 14) Section 11 (Inspection and Testing). This section has been revised to align it with the requirements of AS 2885.5. It specific strength test endpoint requirements for pipelines with a pressure design factor of 0.80, and references APIA research and associated software designed to enable the analysis of the pipe in a proposed (and constructed) test section to be analysed to determine the presence and location of pipe that may be exposed to excessive strain at the intended strength test pressure. 15) Section 12 (Records) Obligations on the developer of a new pipeline to document the design and construction, and to transfer this information to the pipeline operator are clarified and expanded. 16) Appendices Each appendix in the 1997 revision of the standard has been critically reviewed and revised as appropriate. New appendices are provided DR04561.doc
DRAFT ONLY
5
DRAFT ONLY
reflecting the findings of APIA research, clarification of concepts in the Standard, and providing detailed calculation methods. In addition to the items identified above, there are a great many changes of lesser significance incorporated in the document to the extent that users should consider it as a familiar, but new Standard.
DR04561.doc
DRAFT ONLY
6
DRAFT ONLY
CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE......................................................................................................................... 9 1.2 REFERENCE DOCUMENTS ..................................................................................... 9 1.3 DEFINITIONS............................................................................................................. 9 1.4 SYMBOLS AND UNITS........................................................................................... 15 1.5 ABBREVIATIONS ................................................................................................... 16 SECTION 2 SAFETY 2.1 BASIS OF SECTION ................................................................................................ 18 2.2 ADMINISTRATIVE REQUIREMENTS................................................................... 19 2.3 OVERVIEW OF PROCESS ...................................................................................... 21 2.4 PIPELINE RISK MANAGEMENT ........................................................................... 24 2.5 STATIONS, PIPELINES FACILITIES AND PIPELINE CONTROL SYSTEMS .... 31 2.6 ENVIRONMENTAL RISK MANAGEMENT .......................................................... 31 2.7 ELECTRICAL ........................................................................................................... 34 2.8 CONSTRUCTION & COMMISSIONING ................................................................ 34 SECTION 3 MATERIALS AND COMPONENTS 3.1 BASIS OF SECTION ................................................................................................ 36 3.2 QUALIFICATION OF MATERIALS AND COMPONENTS................................... 36 3.3 REQUIREMENTS FOR COMPONENTS TO BE WELDED.................................... 39 3.4 ADDITIONAL MECHANICAL PROPERTY REQUIREMENTS ............................ 39 3.5 REQUIREMENTS FOR TEMPERATURE AFFECTED ITEMS.............................. 40 3.6 MATERIALS TRACEABILITY AND RECORDS ................................................... 40 3.7 RECORDS................................................................................................................. 41 SECTION 4 PIPELINE GENERAL 4.1 BASIS OF SECTION ................................................................................................ 42 4.2 ROUTE...................................................................................................................... 45 4.3 PIPELINE MARKING .............................................................................................. 46 4.4 CLASSIFICATION OF LOCATIONS ...................................................................... 48 4.5 SYSTEM DESIGN .................................................................................................... 51 4.6 ISOLATION .............................................................................................................. 53 4.7 SPECIAL PROVISIONS FOR HIGH CONSEQUENCE AREAS............................. 55 4.8 FRACTURE CONTROL ........................................................................................... 57 4.9 LOW TEMPERATURE EXCURSIONS ................................................................... 63 4.10 ENERGY DISCHARGE RATE............................................................................... 64 4.11 RESISTANCE TO PENETRATION ......................................................................... 64 SECTION 5 PIPELINE DESIGN 5.1 BASIS OF SECTION ................................................................................................ 67 5.2 DESIGN PRESSURE ................................................................................................ 67 5.3 DESIGN TEMPERATURES ..................................................................................... 68 5.4 WALL THICKNESS ................................................................................................. 68 5.5 EXTERNAL INTERFERENCE PROTECTION........................................................ 70 5.6 PRE-QUALIFIED PIPELINE SAFETY DESIGN .................................................... 77 5.7 STRESS AND STRAIN............................................................................................. 79 5.8 SPECIAL CONSTRUCTION ................................................................................... 85 5.9 PIPELINES ASSEMBLIES ..................................................................................... 118 DR04561.doc
DRAFT ONLY
7
DRAFT ONLY
5.10 JOINTING ............................................................................................................... 120 5.11 SUPPORTS AND ANCHORS................................................................................. 121 SECTION 6 STATION DESIGN 6.1 BASIS OF SECTION .............................................................................................. 124 6.2 DESIGN .................................................................................................................. 124 SECTION 7 INSTRUMENTATION AND CONTROL DESIGN 7.1 BASIS OF SECTION ............................................................................................. 133 7.2 CONTROL AND MANAGEMENT OF PIPELINE SYSTEM ................................ 133 7.3 FLUID QUALITY ASSURANCE ........................................................................... 135 7.4 SCADA.................................................................................................................... 135 7.5 COMMUNICATION ............................................................................................... 136 7.6 CONTROL FACILITIES......................................................................................... 136 7.7 CRITICAL EQUIPMENT AND REDUNDANCY/BACKUP ................................. 136 SECTION 8 MITIGATION OF CORROSION 8.1 BASIS OF SECTION .............................................................................................. 137 8.2 PERSONNEL .......................................................................................................... 137 8.3 RATE OF DEGRADATION ................................................................................... 137 8.4 CORROSION MITIGATION .................................................................................. 138 8.5 CORROSION MONITORING ................................................................................ 139 8.6 INTERNAL CORROSION MITIGATION METHODS .......................................... 139 8.7 EXTERNAL CORROSION MITIGATION METHODS ......................................... 140 8.8 EXTERNAL ANTI-CORROSION COATING ........................................................ 143 8.9 INTERNAL LINING ............................................................................................... 144 SECTION 9 UPGRADE OF MAOP 9.1 BASIS OF SECTION .............................................................................................. 146 9.2 MAOP UPGRADE PROCESS ................................................................................ 146 SECTION 10 CONSTRUCTION 10.1 BASIS OF SECTION .............................................................................................. 150 10.2 SURVEY ................................................................................................................. 150 10.3 HANDLING OF COMPONENTS ........................................................................... 150 10.4 INSPECTION OF PIPE AND COMPONENTS....................................................... 151 10.5 CHANGES IN DIRECTION ................................................................................... 152 10.6 COLD-FIELD BENDS ............................................................................................ 153 10.7 FLANGED JOINTS................................................................................................. 154 10.8 COVERING SLABS, BOX CULVERTS, CASINGS AND TUNNELS.................. 154 10.9 SYSTEM CONTROLS ............................................................................................ 154 10.10 ATTACHMENT OF ELECTRICAL CONDUCTORS ............................................ 155 10.11 LOCATION ............................................................................................................. 156 10.12 CLEARING AND GRADING ................................................................................. 156 10.13 TRENCH CONSTRUCTION .................................................................................. 156 10.14 INSTALLATION OF A PIPE IN A TRENCH ........................................................ 157 10.15 PLOUGHING-IN AND DIRECTIONALLY DRILLED PIPELINES...................... 158 10.16 SUBMERGED CROSSINGS .................................................................................. 159 10.17 REINSTATEMENT................................................................................................. 159 10.18 CLEANING AND GAUGING PIPELINES ............................................................ 159 SECTION 11 INSPECTIONS AND TESTING 11.1 GENERAL............................................................................................................... 160 11.2 INSPECTION AND TEST PLAN AND PROCEDURES........................................ 160 11.3 PERSONNEL .......................................................................................................... 160 DR04561.doc
DRAFT ONLY
8
DRAFT ONLY
11.4 PRESSURE TESTING ............................................................................................ 160 11.5 COMMENCEMENT OF PATROLLING ................................................................ 163 SECTION 12 DOCUMENTATION 12.1 RECORDS .............................................................................................................. 164 12.2 RETENTION OF RECORDS ................................................................................. 165
APPENDICES A REFERENCED DOCUMENTS............................................................................... 166 B DESIGN CONSIDERATIONS FOR EXTERNAL INTERFERENCE PROTECTION......................................................................................................... 171 C INTEGRITY ASSESSMENT OF PIPELINE RISK ASSESSMENTS CONDUCTED IN ACCORDANCE WITH AS 2885 .............................................. 174 D EFFECTIVENESS OF PROCEDURAL MEASURES FOR THE PREVENTION OF EXTERNAL INTERFERENCE DAMAGE TO PIPELINES............................. 184 E PREFERRED METHOD FOR TENSILE TESTING OF WELDED LINE PIPE DURING MANUFACTURE ................................................................................... 191 F FRACTURE TOUGHNESS TEST METHODS ...................................................... 192 G FRACTURE CONTROL PLAN FOR STEEL PIPELINES ..................................... 194 H STATION PIPING STANDARDS AND DESIGN FACTORS .............................. 198 I ....................................................................................................................................... J FATIGUE ................................................................................................................ 200 K MAOP UPGRADE .................................................................................................. 203 L SUITABILITY OF ASSOCIATED STATION EQUIPMENT................................. 204 M FACTORS AFFECTING CORROSION.................................................................. 205 N ENVIRONMENT RELATED CRACKING ............................................................ 208 O INFORMATION FOR CATHODIC PROTECTION ............................................... 215 P MITIGATION OF A.C. EFFECTS FROM HIGH VOLTAGE ELECTRICAL POWERLINES ....................................................................................................... 217 Q CHANGE IN INTEGRITY (DUE TO DEFECTS IN SERVICE) KNOWN CORROSION DEFECTS PAPER 5.13 ........................................................ 225 R PROCEDURE QUALIFICATION FOR COLD FIELD BENDS............................. 226 S GUIDELINES FOR THE TENSIONING OF BOLTS IN THE FLANGED JOINTS OF PIPING SYSTEMS.............................................................................. 231 T STRATEGIC SPARES PAPER 5.21 ....................................................................... 245 U RECORD KEEPING PAPER 5.2 ............................................................................ 246 V STRESS TYPES & DEFINITIONS ......................................................................... 247 W EXTERNAL LOADS .............................................................................................. 254 X COMBINED EQUIVALENT STRESS.................................................................... 258 Y PIPE STRESS ANALYSIS...................................................................................... 269
DR04561.doc
9
DRAFT ONLY
DRAFT ONLY
STANDARDS AUSTRALIA Australian Standard Pipelines—Gas and liquid petroleum Part 1: Design and construction
S EC T ION
1
S C OP E
AND
GENER A L
1.1 SCOPE This Standard specifies requirements for the design and construction of carbon and carbonmanganese steel pipelines falling within the scope of AS2885 Part 0 and associated piping and components that are used to transmit single phase and multiphase hydrocarbon fluids, such as natural and manufactured gas, liquefied petroleum gas, natural gasoline, crude oil, natural gas liquids and liquid petroleum products. AS 2885 Part 0 defines the principles for design, construction, operation and abandonment of petroleum pipelines that form the basis for Design and construction, Welding, Operation and maintenance and Field hydrostatic testing in accordance with AS2885 Parts 1, 2, 3, and 5. The principles are expressed in practical rules and guidelines for use by competent persons. The fundamental principles and the practical rules and guidelines set out in AS2885 Parts 1, 2, 3, and 5 are the basis on which an engineering assessment is to be made where these Standards do not provide detailed requirements appropriate to a specific item. NOTE: AS 2885.4 for offshore pipelines is a standalone document.
Where approved, this Standard may also be used for design and construction of pipelines made with corrosion resistant alloy steels or fibreglass. Where this Standard is used for pipelines fabricated from these materials appropriate requirements shall be established to replace the provisions of this standard in relation to nominated standards for Materials (Section 3), Fracture Control (Section 4.8), Stress and Strain (Section 5.7) and Corrosion (Section 8) and the provisions of AS 2885.2 in relation to Welding and Non Destructive Examination. For fibreglass appropriate requirements shall be established to replace the hydrostatic strength test endpoint provisions of AS2885.5. This standard is complementary to AS2885.0 but the requirements of this standard take precedence over any corresponding requirements in AS2885.0. 1.2 REFERENCE DOCUMENTS The documents referred to in this Standard are listed in Appendix A. 1.3 DEFINITIONS For the purpose of this standard the definitions in AS2885.0 shall apply. Where this standard imposes requirements, which add to or override the requirements of a permitted Standard or Code, the additional requirements are explicitly stated in this standard and shall be met. For the purpose of the Standard, the definitions given in AS 1929, AS 2812, AS 2832.1 and those below, apply.
DR04561.doc
10
DRAFT ONLY
DRAFT ONLY
1.3.1 Accessory A component of a pipeline other than a pipe, valve or fitting, but including a relief device, pressure-containing item, hanger, support and every other item necessary to make the pipeline operable, whether or not such items are specified by the Standard. 1.3.2 Approved and approval Approved by the Licensee, and includes obtaining the approval of the relevant regulatory authority where this is legally required. Approval requires a conscious act and is given in writing. 1.3.3 As Low as Reasonably Practicable Means the cost of further risk reduction measures is grossly disproportionate to the benefit gained from the reduced risk that would result. NOTE: Guidance on the demonstration of ALARP and grossly disproportionate is given Appendix ALARP
1.3.4 Buckle An unacceptable irregularity in the surface of a pipe caused by a compressive stress. 1.3.5 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. 1.3.6 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). 1.3.7 Competent person A person who has acquired through training, qualification, or experience, or a combination of these, the knowledge and skills enabling the person to perform the task required. 1.3.8 Common threats Threats which occur at similar locations along the pipeline and which can therefore be treated by a standard design solution for that location type (e.g. road crossings). 1.3.9 Component Any part of a pipeline other than the pipe. 1.3.10 Construction Activities required to fabricate, construct and test a pipeline, and to restore the right of way of a pipeline. 1.3.11 Control piping Ancillary piping used to interconnect control or instrument devices or testing or proving equipment. 1.3.12 Controlled threat A threat is considered to be controlled when the application of multiple independent protective measures (physical and procedural for external interference and design and/or procedures for other threats) in accordance with this Standard means that for all practical purposes failure as a result of that threat has been removed at that location.
DR04561.doc
DRAFT ONLY
11
DRAFT ONLY
1.3.13 Critical Defect Length The length of a through wall axial flaw that if exceeded, will grow by plastic failure and result in pipeline rupture. When the defect is smaller than this length, the pipeline will leak. A critical defect length also exists for part through wall flaws. 1.3.14 Defect A discontinuity or imperfection of sufficient magnitude to warrant rejection on the basis of the requirements of this Standard. 1.3.15 Dent A depression in the external surface of the pipe caused by mechanical damage that 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). 1.3.16 Diameter The outside diameter nominated in the material order. 1.3.17 Failure Analysis Threats which have not been reduced to accepted risk by external interference protection design or other design measures are then assessed to determine whether or not they will cause failure of the pipeline at the location of the threat. This combination of the characteristics of the threat and the characteristics of the pipeline is called failure analysis. Failure analysis determines the outcome from the identified threat. 1.3.18 Failure For the purpose of safety assessment, failure within the Pipeline System has occurred if one or more of the of the following conditions apply: (a)
Any loss of containment
(b)
Supply is restricted
(c)
MAOP is reduced
(d)
Immediate repair is required
NOTE: It is emphasised that failure is not restricted to loss of containment.
1.3.19 Failure Event An event that has not been reduced to an accepted risk by external interference protection or design processes, and which involves failure. Failure events are subject to risk evaluation and risk management. Threats that are not reduced to accepted risk become failure events, where their effect on a pipeline results in failure. 1.3.20 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. 1.3.21 Fluid Any liquid, vapour, gas or mixture of any of these. 1.3.22 Gas Any hydrocarbon gas or mixture of gases, possibly in combination with liquid petroleum condensates or water.
DR04561.doc
12
DRAFT ONLY
DRAFT ONLY
1.3.23 Heat Material produced from a single batch of steel processed in the final steel making furnace at the steel plant. 1.3.24 High Consequence Areas Locations where pipeline failure can be expected to result in multiple fatalities or major environmental damage. 1.3.25 High Consequence Events Failure events in high consequence areas. 1.3.26 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. 1.3.27 Hoop stress Circumferential stress in a cylindrical pressure containing component arising from internal pressure. 1.3.28 Hot tap A connection made to an operating pipeline containing hydrocarbon fluid. 1.3.29 Imperfection A material discontinuity or irregularity that is detectable by inspection in accordance with this Standard. 1.3.30 Inert gas A non-reactive and non-toxic gas such as argon, helium and nitrogen. 1.3.31 Inspector A person appointed by the licensee to carry out inspections required by this Standard. 1.3.32 Leak test A pressure test that determines whether a pipeline is free from leaks. 1.3.33 Location class An area classified according to its general geographic and demographic characteristics. 1.3.34 Mainline pipework Those parts of a pipeline between stations, including fabricated assemblies (see AS 2885.1) 1.3.35 Maximum allowable operating pressure (MAOP) The maximum pressure at which a pipeline or section of a pipeline may be operated. 1.3.36 May Indicates the existence of an option. 1.3.37 Mechanical interference-fit joint A joint for pipe, involving a controlled plastic deformation and subsequent or concurrent mating or pipe ends. 1.3.38 Non-credible threat A threat for which the frequency of occurrence is so low that it does not exist for any practical purpose at that location.
DR04561.doc
13
DRAFT ONLY
DRAFT ONLY
1.3.39 Non-location specific threat Threats which can occur anywhere along the pipeline (e.g. corrosion). 1.3.40 Pipeline Licensee The organization responsible for the design, construction, testing, inspection, operation and maintenance of pipelines and facilities within the scope of this Standard. 1.3.41 Petroleum Any naturally occurring hydrocarbon or mixture of hydrocarbons in a gaseous or liquid state and which may contain hydrogen sulfide, nitrogen, helium and carbon dioxide. 1.3.42 Pig A device that is propelled inside a pipeline by applied pressure. 1.3.43 Pig trap (scraper trap) A fabricated component to enable a pig to be inserted into or removed from an operating pipeline. 1.3.44 Piping An assembly of pipes, valves and fittings connecting auxiliary and ancillary components associated with a pipeline. 1.3.45 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. 1.3.46 Pressure strength The maximum pressure measured at the point of highest elevation in a test section. NOTE: Pressure strength for a pipeline or a section of a pipeline is the minimum of the strength test pressures of the test sections comprising the pipeline or the section of the pipeline.
1.3.47 Proprietary item An item made or marketed by a company having the legal right to manufacture and sell it. 1.3.48 Protection measures–Procedural Measures for protection on a pipeline which minimize the occurrence of activities by third parties, which could cause failure. 1.3.49 Protection measures–Physical Measures for protection of a pipeline which prevent external interference from causing failure. 1.3.50 Regulatory authority An authority with legislative powers relating to petroleum pipelines. 1.3.51 Riser The connection between a submarine pipeline and a fixed structure, such as processing a platform, jetty or pier. 1.3.52 Risk The combination of the frequency, or probability, of occurrence and the consequence of a specified failure event (Note: The concept of risk always has two elements: the frequency or probability of which a failure event occurs and the consequences of the failure event).
DR04561.doc
DRAFT ONLY
14
DRAFT ONLY
1.3.53 Rupture Rupture occurs when a defect size exceeds a critical value, dependent on the applied stress followed by rapid growth until the pipe cylinder has opened to a size equivalent to the diameter of the pipeline. Rupture may initiate propagation of the defect by brittle or tearing fracture until it is arrested. 1.3.54 Shall Indicates that a statement is mandatory. 1.3.55 Should Indicates a recommendation. 1.3.56 Sour service Piping conveying crude oil or natural gas containing hydrogen sulfide together with an aqueous liquid phase in a concentration that may affect materials. 1.3.57 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. 1.3.58 Station pipework Those parts of a pipeline within a station (e.g. pump station, compressor station, metering station) that begin and end where the pipe material specification changes to that for the mainline pipework. 1.3.59 Strength test A pressure test that confirms that the pipeline has sufficient strength to allow it to be operated at maximum allowable operating pressure. 1.3.60 Telescoped pipeline A pipeline that is made up of more than one diameter of MAOP, tested as a single unit. 1.3.61 Threat A threat is any activity or condition that can adversely affect the pipeline if not adequately controlled. NOTE: Additional information on what constitutes a threat is provided in Appendix ZZZ / HB105
1.3.62 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. 1.3.63 Nominated Standard
1.3.64 Loss of integrity Loss of integrity has occurred if one or more of the following conditions apply: (a)
MAOP is reduced.
(b)
Supply is restricted.
(c)
Immediate repair is required.
It will generally occur as a result of significant metal damage to the pipeline.
DR04561.doc
15
DRAFT ONLY
DRAFT ONLY
1.3.65 Loss of integrity event An event that has not been reduced to an accepted risk by external interference protection or design processes, and which involves loss of integrity. Loss of integrity events are subject to risk evaluation and risk management. Threats that are not reduced to accepted risk become loss of integrity events, where their effect on a pipeline results in loss of integrity. 1.3.66 Threat An activity or condition with the potential to damage the pipeline, cause interruption to service or cause release of fluid from the pipeline. 1.3.67 Risk Combination of the frequency, or probability, of occurrence and the consequence of a specified loss of integrity event. NOTE: The concept of risk always has two elements: the frequency or probability of which a loss of integrity event occurs and the consequences of the loss of integrity event.
1.3.68 Pipeline risk assessment The process comprising Risk Identification, Risk Evaluation and Risk Management set out in Section 2 of this Standard, used to ensure that risks imposed by a pipeline are reduced to ALARP / accepted levels. 1.4 SYMBOLS AND UNITS NOTE: Unless otherwise noted, pressure and calculations involving pressure are based on gauge pressures
Symbol
∆S H
Description Stress for longitudinal welds (consistent with API 1102)
Unit MPa
∆S L
Stress for girth welds (consistent with API 1102)
MPa
σ σE
Stress
MPa
Expansion stress range
MPa
σ flow
Flow stress (=SMYS + 68.95 MPa)
MPa
σH
Hoop stress
MPa
σL
Longitudinal stress
MPa
σO
Occasional stress
MPa
σ SUS
Sustained stress
MPa
σU
Ultimate tensile strength
MPa
σY
Yield strength
MPa
µ
Poisson’s ratio (stress and strain)
AC CDL
Fracture area of the Charpy V Notch specimen
mm2
Critical defect length
mm
CV
Upper shelf CharpyVe Notch energy
J
Ca10
Full size specimen (10 x 10 mm) Charpy energy arrest value
J
c
Half of the length of an axial through wall flaw
mm
D
Nominal outside diameter = Pipe diameter = Pipeline diameter
mm
Dm
Average diameter
mm DR04561.doc
16
DRAFT ONLY
DRAFT ONLY
D max
Greatest diameter
Mm
D min d
Smallest diameter Branch diameter
mm mm
dW
Depth of part through wall flaw
mm
E
Young’s modulus
MPa
FD F Bucket
Design factor for Pressure Containment Force exerted at a bucket, correlated against excavator mass
kN
F MAX
Maximum force exerted at bucket (most severe geometry)
kN
F TP F TPE
Test Pressure factor Equivalent test pressure factor
fo
Ovality factor
G
Sum of allowances
L Kc
Length of tooth at tip In plane stress intensification factor (fracture initiation toughness)
MT
Folias factor
PC
Collapse pressure
MPa
PD P EXT
Design pressure External pressure
MPa MPa
PL
Pressure limit
MPa
PM
Measured pressure from hydrostatic test
MPa
P MIN Rp
Minimum strength test pressure Puncture resistance
MPa N
RLi
Number of runs of n p pipe, each run having a length i
SDEV
Standard deviation of toughness in all heat population
S eff SF
Effective stress (consistent with API 1102) Statistical Factor used to calculate minimum toughness for any heat
MPa
S FG
Stress limit for girth weld fatigue (consistent with API 1102)
MPa
S FL
Stress limit for longitudinal weld fatigue (consistent with API 1102)
MPa
t t DP
Wall thickness Wall thickness for internal pressure design
mm mm
tN
Nominal wall thickness
mm
tW W
Required wall thickness
mm
Width of tooth at tip
mm
W OP
Operating weight
mm mm MPa/mm0.5
tonne
1.5 ABBREVIATIONS Abbreviations
Meaning
Unit
ALARP
As low as reasonably practicable
AS
Australian standard
CDL
Critical defect length
CHAZOP
Control hazard and operability
CRA
Corrosion resistant alloy DR04561.doc
17
DRAFT ONLY
CW
Continuously welded
DN
Nominal diameter
DWTT
Drop weight tear test
EIP
External interference protection
EIS
Environmental impact statement
EPRG
European Pipeline Research Group
ERW
Electric resistance welded
FRP
Fibre reinforced plastic
GIS
Geographic information system
HAZ
Heat affected zone
HAZAN
Hazard analysis study
HAZOP
Hazard and operability study
HAZID
Hazard identification study
HVPL
High vapour pressure liquid
JSA
Job safety analysis
LPG
Liquefied petroleum gas
MAOP
Maximum allowable operating pressure
MLV
Main line valve
MOP
Maximum operating pressure
O&M
Operation and maintenance
P&ID
Piping and instrumentation diagram
PDR
Public draft
PRCI
Pipeline research council international
QC
Quality control
SAOP
Safety and operating plan
SAW
Submerged arc welded
SCADA
Supervisory control and data acquisition
SCC
Stress corrosion cracking
SIL
Safety integrity level
SLV
Station limit valve
SMYS
Specified minimum yield stress
XS
Extra strong
DR04561.doc
DRAFT ONLY
MPa MPa
MPa
18
DRAFT ONLY
S E C T ION
2
DRAFT ONLY
S AFE T Y
2.1 BASIS OF SECTION 2.1.1 General This Section provides guidance on techniques which, when implemented rigorously, are sufficient for the review of all activities associated with the pipeline life-cycle to ensure that risks associated with the pipeline are As Low As Reasonably Practical (ALARP). Risks to public safety, supply and the environment arise from threats to the pipeline which have the potential to result in pipeline failure. Risks to public safety, supply and the environment also arise from as a result of construction, operations and maintenance activities. Pipeline risk management is an ongoing process over the life of the pipeline. The pipeline risk management process is designed to ensure that each threat to a pipeline and each risk from immediate or delayed pipeline failure is systematically identified and evaluated, and action to mitigate threats and risks from failure is implemented. The pipeline risk management process is a structured, qualitative process which requires the application of multiple independent measures to protect the pipeline from each identified threat: (a)
Route selection shall be the primary control for avoiding or minimising threats to the pipeline and consequences to the public and environment.
(b)
Physical and procedural and/or design methods are applied to all threats with the objective of controlling them.
(c)
Those threats not controlled by the above are subject to risk evaluation and risk treatment.
Application of Physical and Procedural protection measures to control external interference threats to the pipeline is mandatory, because these threats are known to be the most frequent events that have the potential to create a risk. Furthermore, mandatory requirements are specified in high consequence areas for: (a)
Control of rupture, and
(b)
Maximum energy release rate.
Where land use changes from a low consequence area to a high consequence area this Standard applies mandatory requirements for maintaining the risk at ALARP. The safety of stations, pipeline facilities and pipeline control systems are determined by the application of one or more of a number of recognised safety study methodologies. HAZOP studies of the process design for pipeline facilities is mandatory. The basis for the control of all threats and acceptance of all risks shall be documented and approved. The principles established for risk management for pipeline failure are used to provide guidance on environmental risk management. It is intended that this process be applied when assessing alternative methodologies to mitigate environmental risk through pipeline planning, design, construction and operating phases of its life, irrespective of the existence of other environmental assessment methodologies. Guidance on electrical and construction safety is provided.
DR04561.doc
DRAFT ONLY
19
DRAFT ONLY
The Licensee shall ensure that the pipeline risk management process is carried out by suitably qualified, trained and experienced personnel, and shall demonstrate that the integrity of the assessment process is in accordance with the requirements of Appendix C. Where necessary, other processes, including numerical methods, may be used to assist to determine that an ALARP condition is achieved and to compare and rank the effectiveness of the threat mitigation measures. However, these processes shall complement but not replace the methodology set out in this Standard. Threats controlled in accordance with the provisions of this Standard are considered an accepted risk subject to the continuous application of effective operations and maintenance procedures to monitor and correct any deviations from the design conditions. 2.2 ADMINISTRATIVE REQUIREMENTS 2.2.1 Approval The risk management study and its components shall be approved. 2.2.2 Documentation 2.2.2.1 General All aspects of the risk management process shall be documented with sufficient detail for independent or future users of the risk management study to make an informed assessment of the integrity of the process and its outcomes, including the reasoning behind the assessment of the effectiveness of the mitigation measures applied. NOTE: The risk management study results in a risk management documentation which includes risk management actions which form the basis of the risk management plan.
For new pipelines, or modifications to existing pipelines, the detailed design and the risk management study are undertaken as integrated iterative processes. The output of this process is a design (generally shown on alignment sheets), and a risk management study document (generally recorded on a database). 2.2.2.2 Safety and Operating Plan Where threat mitigation and management requires actions by the pipeline Licensee (e.g. procedural protective measures) the obligations of the Licensee shall be documented in the Safety and Operating Plan (SAOP). The SAOP shall identify that these actions arose from the risk management study and are an integral part of pipeline risk management. NOTES: 1
Because of the SAOP is prepared after the design phase risk management study, the risk management documentation should clearly summarise the obligations of the pipeline operator that arise in order to facilitate transfer of these requirements to the SAOP.
2
The detailed requirements for the incorporation of the risk management study are provided in Part 3.
2.2.3 Implementation All actions arising from the risk management study shall be implemented and the implementation documented. Risk management documentation shall be transferred from the design and construct phase of the project to the operating phase of the project in a form that enables risk management to be undertaken from the time that operation commences. For new pipelines, all actions which are considered necessary for the safe pressurisation of the pipeline shall be completed prior to the commencement of commissioning. For new pipelines, all actions which are considered necessary for the safe operation of the pipeline shall be completed prior to the commencement of operation. DR04561.doc
20
DRAFT ONLY
DRAFT ONLY
For existing pipelines the period for the implementation of each action shall be identified as part of the risk management documentation. The schedule for implementation shall be approved. Where ongoing action is required, a reporting mechanism to demonstrate action shall be established and audited. 2.2.4 Pre-requisites for Risk Management Studies 2.2.4.1 Pre-requisites for an initial risk management study An initial risk management study shall be undertaken to provide for regulatory approvals. It shall consider at least: (a)
Location and zoning information / Location class / Environmental sensitivity assessments / leading to definition of High Consequence Areas.
(b)
Typical threats in typical locations
(c)
Location specific threats, particularly in High Consequence Areas
(d)
Basic pipeline design parameters
(e)
The energy release rate and the contour radius for a radiation intensity of 12.6 and 4.7 kW/m2 in the event of a full bore rupture.
NOTE: A thermal radiation level of 4.7 kW/m2 will cause injury, at least second degree burns, after 30 seconds exposure. A thermal radiation level of 12.6 kW/m2 represents the threshold of fatality, for normally clothed people, resulting in third degree burns after 30 seconds exposure. The energy release is calculated in accordance with Section 4.10. Guidance is provided in HB 105 and API 521, API 581.
2.2.4.2 Detailed Risk Management Study A robust risk management study requires detailed preparatory information & analysis to ensure a consistency of approach across the pipeline and to provide all of the tools necessary to correctly identify ALL threats and facilitate their assessment and control. The risk management study shall be undertaken by personnel with expertise in each component of the design, construction and operation of the pipeline, including, or with the support of, personnel closely familiar with the land uses and environments along the entire route. The following information shall be generated and used for the detailed risk management study: (a)
Design basis and description including: (i)
Basic pipeline properties.
(ii)
Engineering design guidelines for non-standard construction (crossings, facilities etc).
(b)
Design calculations (e.g. thickness).
(c)
Initial pipeline alignment.
(d)
Typical design drawings (crossings, facilities etc).
(e)
Risk management study of common threats to typical designs
(f)
Documented investigations of external threats including information from land owner/holder, public / planning authority, construction contractor
(g)
Documented investigations of external threats from existing and planned buried and above ground infrastructure crossing and parallel to the pipeline
DR04561.doc
21
DRAFT ONLY
DRAFT ONLY
(h)
An assessment of current land uses, and plans for future land use (based on information from landowners and land planning authorities).
(i)
Construction line list (list of construction and landowner constraints)
(j)
Environmental line list (list of environmental constraints)
(k)
Preliminary Safety and Operating Plan (which provides first drafts of standard procedural measures, such as patrolling, land access procedures etc).
(l)
Isolation Plan
(m)
HAZOP and other design review studies applied to stations, pipeline facilities and pipeline control systems.
(n)
Fracture Control Plan
(o)
Critical defect length / rupture case / resistance to penetration.
(p)
Consequence modelling. Consequence modelling shall include the energy release rate and the contour radius for a radiation intensity of 12.6 and 4.7 kW/m2 in the event of a full bore rupture. Consequence modelling shall include an assessment of the impacts of a fluid release on people, property and the environment, and shall take into account factors such as the nature of the fluid released, topography and prevailing weather conditions.
(q)
Environmental studies and information developed specifically for the pipeline project or as otherwise may be available for the route traversed by the pipeline.
NOTE: Electronic Tools (eg. Risk database, GIS) can greatly assist both in process of risk assessment and in documenting its deliberations and outcomes, and allowing decisions to be made transparently.
For in-service pipelines, in addition to the foregoing, the information shall also include: (a)
Land use changes
(b)
Changes in population density
(c)
As-built drawings
(d)
Maintenance history
(e)
Previous risk assessment studies
If any of the above items are considered to be not applicable the reason for exclusion from the risk management study shall be documented and approved. 2.2.5 Risk Management Study Validation Each detailed risk management study shall be validated by a properly constituted workshop(s) which shall review the risk management study in detail and either approve or recommend actions necessary to control the risk from each identified threat to ALARP. The information requirements listed in Section 2.4.2 are essential for the detailed risk assessment validation workshop, and shall be considered in the workshop. NOTE: Guidance on risk management study validation is provided in Appendix C.
2.3 OVERVIEW OF PROCESS 2.3.1 Whole of Life Pipeline Risk Management Pipeline Risk assessment to this Standard is an integral component of the planning, design, construction, operation and abandonment of the pipeline. Figure 2.3.1 illustrates the components of the process and their interrelationship.
DR04561.doc
22
DRAFT ONLY
DRAFT ONLY
WHOLE OF LIFE PIPELINE RISK MANAGEMENT
PRELIMINARY DESIGN AND APPROVAL
Preliminary Design System Design Feasibility Study
Environmental Impact Assessment
Route Selection
Initial Pipeline Risk Risk Assessment Pipeline Licence Approval
System Design Commercial Design a Delivery Points Hydraulic Design a Compressor stations SAOP a Scraper Stations Isolation Plan a MLVs and SLVs
Pipeline Risk Assessment
Process Design
Avoid by route selection Apply Physical & Procedural Measures Apply Design Damage Analysis Risk Evaluation Risk Management
AS 2885 SECTION 2
DETAILED DESIGN
Pipeline Design
PIDs, Equipment, Layout Process Safety a HAZOP Control System Safety a CHAZOP Electronic Systems Safety a SIL Societal Safety a HAZAN
Review and Validate
Construction Safety Plan, Environmental Management Plan, Risk Assessment of Plans / JSA
Approval to Construct Commissioning Safety Commissioning Plan, Safety and Operating Plan, As constructed Risk Assessment / Review
ABANDON
OPERATE, MAINTAIN, MODIFY
Approval to Commission
Operations Safety Safety and Operating Plan, Environment Plan, Training, Audits, Integrity Inspections, Risk Assessment Review
Abandon Pipeline Abandonment Plan, Environment Plan, Maintenance Plan, Risk Assessment
FIGURE 2.3.1 WHOLE OF PIPELINE RISK MANAGEMENT
DR04561.doc
16 October 2004 version
CONSTRUCT AND COMMISSION
Construction Safety
23
DRAFT ONLY
DRAFT ONLY
2.3.2 Project Phases 2.3.2.1 General The risk management process involves periodic re-assessment of threats and the implementation of measures to mitigate them which evolves as knowledge of the threats is gained over time. The risk management study shall be reviewed at intervals during the pipeline design, construction and operational cycles. As a minimum, reviews shall be conducted at the following phases. 2.3.2.2 Initial Design Phases The initial design is typically developed as part of a feasibility study undertaken early in the life of the project. It is also generally used as the basis to obtain regulatory approvals for the project. The initial design shall include an initial assessment of risks to the community and the environment. The initial risk management study shall identify “high consequence events” that impose major risks to the project, community and environment, and their mitigation. The initial design shall generate sufficient information to allow this study to be carried out effectively. The initial risk management study will deliver sufficient information to allow stakeholders involved in the regulatory approvals process to make informed decisions about the risks associated with the project The initial risk management study must recognise that detailed design will identify detailed threats and develop specific procedures for their mitigation. NOTE: The study should be consistent with the requirements of the relevant licensing authority. These may vary from jurisdiction to jurisdiction and should be clarified at the earliest opportunity.
2.3.2.3 Detailed Design Phase A risk management study which complies with this Standard shall be undertaken in parallel with the design. NOTE: The application of the risk management process is an integral part of pipeline system design, and cannot be performed independently from the design process. This allows the pipeline design to be continually refined on the basis of pipeline risk management information.
2.3.2.4 Pre-Construction Review The review shall determine that the design complies with this Standard prior to construction. Each corrective action that relates to the physical pipeline shall be implemented prior to or during the construction of the affected part of the pipeline. 2.3.2.5 Pre-Commissioning Review The review shall confirm that the constructed pipeline complies with the requirements of this Standard prior to commissioning. Where the pipeline route or its design has been changed during construction, the compliance of each change with the requirements of this Standard shall be established. The review shall confirm that the requirements of the risk management study have been incorporated into the Safety and Operating Plan. 2.3.2.6 Operational Review A risk management study shall be conducted as a result of any of the following triggers: (a)
At intervals not exceeding five years DR04561.doc
24
DRAFT ONLY
(b)
At any review for changed use
(c)
At any review for extension of design life
(d)
At any review to increase MAOP
(e)
As may be required by AS 2885.3
(f)
At any other time that new or changed threats occur
DRAFT ONLY
Where a trigger point relates to a part of the pipeline (for example a change at a specific location), the risk management study may be restricted to only that part which is changed. An assessment of the implementation and effectiveness of the controls required by the design and risk management study shall be made at each Operational Review. 2.4 PIPELINE RISK MANAGEMENT 2.4.1 General The pipeline risk management process consists of four stages: (a)
Threat Identification
(b)
Initial Threat Control
(c)
Risk Evaluation of “failure threats”
(d)
Risk Treatment
Figure 2.4.1 illustrates the Pipeline Risk Management Process. This section describes the detail and application of risk management process.
DR04561.doc
24
DRAFT ONLY
DRAFT ONLY
Description of design and operation
THREAT IDENTIFICATION / LOCATION ANALYSIS
Common Threats / Common Threat Locations / Standard Design
Location analysis Non location related threats
Threat analysis / specification
5 Oct 2004 version
Is threat credible?
NO
YES Apply External Interference Protection (where applicable) Apply Design & Procedures & HAZOP (where applicable)
Threat controlled?
YES
NO Failure analysis
THREAT CONTROL
Failure?
NO
YES Failure Event
RISK EVALUATION
Consequence analysis
HIGH Reduce
LOW / NEGLIGIBLE Assess INTERMEDIATE
RISK TREATMENT
Re-evaluate HIGH
NOTE: All stages of the process must be documented.
Frequency analysis
RISK RANKING
LOW Re-Assess STILL INTERMEDIATE Reduce to ALARP
FIGURE “PIPELINE RISK MANAGEMENT PROCESS”
Management Plan
ACCEPTED RISK
FIGURE 2.4.1 PIPELINE RISK MANAGEMENT PROCESS DR04561.doc
DRAFT ONLY
25
DRAFT ONLY
2.4.2 Threats 2.4.2.1 General The underlying principle of threat identification is that “a threat exists at a location”. Threats exist at either specific locations (e.g. excavation threat at a particular road crossing), specific sections of a pipeline (e.g. farming; forestry; fault currents for sections with parallel power lines), or over the entire length of the pipeline (e.g. corrosion). NOTE: Threats which apply to the entire pipeline are considered non-location-specific, and are often qualitatively different to location-specific threats (eg. Corrosion, versus external interference threats at a road crossing). The same risk assessment process applies to both location-specific and non-location-specific threats.
2.4.2.2 Location analysis The pipeline route should be analysed to divide it into risk assessment sections, for each of which the land use and population density is consistent. A risk assessment section shall not contain more than one location class. NOTES: 1
Use of risk assessment sections facilitates the threat analysis for threats that apply over whole sections of the route (eg. Farming, forestry, urban development, etc).
2
It is recommended that data sources to be used to conduct the location analysis include: alignment survey data to determine basic geographical information; land user surveys in which land liaison officers gather information from land users on the specific activities carried out on the land, and obtain any other “local knowledge”; third-party spatial information (GIS type data) on earthquakes, drainage, water tables, soil stability, near-surface geology, environmental constraints etc; land planning information.
2.4.2.3 Threat identification Threat identification shall be conducted for the full length of the pipeline, including stations and pipeline facilities. The threats to be considered shall include external interference, corrosion, natural events, electrical effects, operations and maintenance activities, construction defects, design defects, material defects, intentional damage and other threats such as seismic and blasting. The threat identification shall consider all threats with the potential to damage the pipeline, cause interruption to service, cause release of fluid from the pipeline, or cause harm to pipeline operators, the public or the environment. The threats identification must generate sufficient information about each threat to allow external interference protection and engineering design to take place. For each identified threat, the following minimum information shall be recorded: (a)
What is the threat to the pipeline?
(b)
Where does it occur? (The location of the threat)
(c)
Who (or what) is responsible for the activity?
(d)
What is done? (e.g. depth of excavation)
(e)
When is it done? (Frequency of the activity, time of the year)
(f)
What equipment is used? (e.g. power of plant, characteristics of the excavator teeth, etc)
The description shall be sufficiently detailed for independent or future reviewers of the risk management study to make an informed assessment of the identified threat and its potential consequence. 2.4.2.4 Common Threats to Typical Designs The pipeline design process involves the development and application of typical designs to locations where there is a common range of design conditions and identified threats. Where DR04561.doc
DRAFT ONLY
26
DRAFT ONLY
the pipeline design uses typical designs the threats common to that design shall be documented. Each typical design shall be subjected to the risk management process in accordance with this Standard to demonstrate that the threats are mitigated by that design. 2.4.2.5 Other Threats at Typical Design Locations Each location at which a typical design is applied shall be assessed to determine whether threats other than the approved threats “common” to that design exist at that location. Where identified, effective threat mitigation measures shall be applied to each of these location specific threats and the effectiveness of the additional mitigation measures shall be assessed. 2.4.2.6 Non-credible threats Each non-credible threat and the reason for it being declared “non-credible” shall be documented. Non-credible threats are considered accepted risk. The correctness of this decision shall be considered at each review of the risk assessment. 2.4.3 Threat Control by External Interference Protection or Design 2.4.3.1 General Each credible threat shall be subject to a systematic process to control the threat. For external interference threats, external interference protection measures shall be applied. For those threats for which external interference protection is either not effective or not applicable, design and/or procedure shall be applied. Threats that are not controlled by this process shall be subject to failure analysis. 2.4.3.2 Threat control by external interference protection The whole of the pipeline shall be protected from external interference by a combination of physical and procedural measures applied to mitigate the identified threats at each location. The minimum number of physical and procedural measures that must be applied at a location are varied by the location class. Physical external interference protection for the full length of the pipeline shall be designed in accordance with Section 5.5. The physical measures applied shall be demonstrated to protect the pipeline from the specified threat. NOTE: Guidance on resistance to penetration calculations is provided in Section 4.11.
Procedural external interference protection for the full length of the pipeline shall be designed in accordance with Section 5.5. The procedural measures shall be demonstrated to be effective in contributing to reducing the frequency of the occurrence of that threat. NOTE: Guidance on the effectiveness of procedural measures is provided in Appendix D.
External interference threats that are not controlled by external interference protection shall be considered for control by development of additional specific design and/or procedures. NOTE: Re-routing is a design change decision that may be taken here if EIP is not sufficient, prior to undertaking risk evaluation.
Threats controlled by effective physical measures and with the required procedural protection are considered accepted risk. 2.4.3.3 Control of other threats by design and/or procedures For threats for which external interference protection is not applicable, specific design and/or procedures shall be applied. Materials shall be specified, qualified and inspected in accordance with Section 3. Pipeline design shall be carried out in accordance for with Section 4 and Section 5.
DR04561.doc
DRAFT ONLY
27
DRAFT ONLY
Protection against stress and strain shall be designed in accordance with Section 5.7. Operational controls for the full length of the pipeline shall be designed in accordance with Section 7. Corrosion and erosion protection for the full length of the pipeline shall be designed in accordance with Section 8. Guidance on design for environment related cracking is provided in Appendix O. Protection against construction related defects shall be in accordance with Section 10. Induced voltage, lightning and fault current protection for sections of the pipeline affected by these conditions shall be designed in accordance with AS 4853. Further guidance on design for electrical hazards is provided in Appendix Q of this Standard. Other threats requiring specific control by design and/or procedures include: (a)
Operational releases
(b)
Loss of communication leading to loss of control
(c)
Temperature outside design range
(d)
Natural events (landslip, seismic activity, flotation and erosion).
(e)
Threats arising through operating and maintenance activities
(f)
Fluid composition
Threats controlled by effective design and/or procedures are considered accepted risk. 2.4.4 Failure Analysis 2.4.4.1 General Each threat that is not controlled by external interference protection or design and/or procedures shall be analysed to determine the damage that the threat may cause to the pipeline. The analysis shall determine whether the damage resulting from a threat results in a failure. Where the outcome is failure the analysis shall determine the mode of failure (significant metal damage, leak or rupture) and the energy release rate at the point of failure (if applicable) as inputs to the consequence analysis. Each failure event shall be subjected to risk evaluation and risk control. The analysis may conclude there is no immediate or delayed failure, in which case the threat is reduced to accepted risk. Appropriate management action shall be identified. Guidance on failure analysis is provided in Appendix Z.
DR04561.doc
28
DRAFT ONLY
DRAFT ONLY
FAILURE TREE EXAMPLE EXTERNAL INTERFERENCE THREAT OCCURS
PIPELINE DAMAGE
HIT?
NO
NEAR MISS
YES
COATING DAMAGE
• MAOP not reduced • Maintenance repair
FAILURE
SUPERFICIAL METAL DAMAGE
SIGNIFICANT METAL DAMAGE
• MAOP reduced MAOP REDUCTION
• Supply restr icted
LOSS OF CONTAINMENT
• Immediate repair
Note 1: Procedural errors such as failure to correctly follow venting procedures result in uncontrolled gas release and injur y/fatality.
ENVIRONMENTAL DAMAGE FIRE / EXPLOSION
Note 2: Loss of containment resulting in energy release rates of 1 GJ/s (T2) and 10 GJ/s (T1) are prohibited.
INJURY / FATALITY
Figure 2.4.4.1
DR04561.doc
28
DRAFT ONLY
DRAFT ONLY
2.4.4.2 2.4.4.3 Documentation The failure analysis for the specific threat shall document (as applicable): (a)
The pipeline design features.
(b)
The threat.
(c)
Mode of failure.
NOTE: Modes of failure include rupture as a running crack in brittle fracture mode, rupture as a ductile tear, hole, pinhole, crack, dent, gouge, loss of wall thickness.
(d)
The physical dimensions of the failure.
(e)
Location of the failure.
(f)
Nature of the escaping fluid.
(g)
The energy release rate and the contour radius for a radiation intensity of 12.6 and 4.7 kW/m2 .
(h)
Environmental effects at the location (eg. wind)
(i)
For fluids with potential to cause environmental damage, the volume release and other factors related to the spread of the fluid in the environment (eg. oil and drainage systems). NOTE: Some of this information can be addressed in a generic manner for a given set of pipeline parameters, and does not necessarily have to be documented against every threat analysed.
2.4.5 Risk Evaluation 2.4.5.1 General Consequence analysis and frequency analysis shall be conducted for each failure event. The risk shall be evaluated for each failure event. Where a failure event may have several outcomes, each outcome shall be considered. Full evaluation of every outcome may not be necessary, but sufficient outcomes shall be evaluated to identify the outcome with the highest risk ranking. NOTE: The highest energy release rate may not give rise to the highest consequence or the highest risk (eg. A small LPG leak which is initially unignited may well have a higher consequence or higher risk ranking than a large immediately ignited release).
2.4.5.2 Consequence Analysis The severity of the consequences of each failure event shall be assessed. Consequences to be assessed shall include the potential for— (a)
Human injury or fatality;
(b)
Interruption to continuity of supply with economic impact; and
(c)
Environmental damage.
NOTES: 1
Other factors such as property damage and loss of reputation may also be considered.
2
Gas pipelines and some liquid petroleum pipelines may be identified as “essential infrastructure” where the consequence of a loss of supply is significant. This may be in terms of the potential for economic impact, and in some cases significant fatalities may result from the cascading consequence of loss of the energy supply.
The consequence analysis for each failure event shall derive the extent of effect of the consequences at that location and shall include assessment of location specific environmental parameters. DR04561.doc
29
DRAFT ONLY
DRAFT ONLY
The description of the severity classes based on Table “risk matrix” shall be established for the pipeline under study and used in the risk matrix which determines the risk rank. In establishing pipeline-specific severity classes description, the severity classification shall be maintained, but the description of the consequences associated with each classification shall be reviewed and approved. The reasons for any changes to the severity class description shall be documented and approved. 2.4.5.3 Frequency analysis A frequency of occurrence of each failure event shall be assigned for each location where risk estimation is required. The frequency of occurrence shall be selected from Table 2.4.5. The contribution of operations and maintenance practices and procedures to the occurrence of or prevention of failure events may be considered in assigning the frequency of occurrence to each failure event at each location. 2.4.5.4 Risk Ranking Table “risk matrix” shall be used to combine the results of frequency analysis and consequence analysis. Risks determined to be low, negligible or demonstrated to be ALARP are accepted risks. TABLE 2.4.5 RISK MATRIX CATASTROPHI C
People
Multiple fatalities result.
Few fatalities, or several people with lifethreatening injuries
Injury or illness requiring hospital treatment
Injuries requiring first aid treatment
Minimal impact on health & safety
Supply
Long term interruption of supply
Prolonged interruption or long-term restriction of supply
Short term interruption prolonged restriction of supply
Short term interruption or restriction of supply but shortfall met from other sources
No impact; no restriction of pipeline supply
Effects widespread; viability of ecosystems or species affected; permanent major changes
Major offsite impact or long-term severe effects or rectification difficult
Localised (
