1、Gas Transmission and Distribution Piping SystemsASME Code for Pressure Piping, B31AN INTERNATIONAL PIPING CODEASME B31.8-2016(Revision of ASME B31.8-2014)ASME B31.8-2016(Revision of ASME B31.8-2014)Gas Transmissionand DistributionPiping SystemsASME Code for Pressure Piping, B31AN INTERNATIONAL PIPIN
2、G CODETwo Park Avenue New York, NY 10016 USADate of Issuance: October 19, 2016The next edition of this Code is scheduled for publication in 2018. This Code will become effective6 months after the Date of Issuance.ASME issues written replies to inquiries concerning interpretations of technical aspect
3、s of this Code.Interpretations are published on the Committee Web page and under go.asme.org/Interpretations.Periodically certain actions of the ASME B31 Committee may be published as Cases. Cases arepublished on the ASME Web site under the B31 Committee Page at go.asme.org/B31committee asthey are i
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11、endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any for
12、m,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersTwo Park Avenue, New York, NY 10016-5990Copyright 2016 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword
13、 viiiCommittee Roster . xIntroduction . xivSummary of Changes xviGeneral Provisions and Definitions 1801 General . 1802 Scope and Intent 1803 Piping Systems Definitions 2804 Piping Systems Component Definitions 4805 Design, Fabrication, Operation, and Testing Terms andDefinitions . 7806 Quality Assu
14、rance 12807 Training and Qualification of Personnel 12Chapter I Materials and Equipment . 14810 Materials and Equipment . 14811 Qualification of Materials and Equipment . 14812 Materials for Use in Low-Temperature Applications 14813 Marking 15814 Material Specifications 15815 Equipment Specification
15、s 16816 Transportation of Line Pipe . 16817 Conditions for the Reuse of Pipe 16Table817.1.3-1 Tensile Testing 17Chapter II Welding . 19820 Welding 19821 General . 19822 Preparation for Welding . 19823 Qualification of Procedures and Welders . 19824 Preheating 20825 Stress Relieving . 20826 Weld Insp
16、ection Requirements . 21827 Repair or Removal of Defective Welds in Piping Intendedto Operate at Hoop Stress Levels of 20% or More ofthe Specified Minimum Yield Strength 22Chapter III Piping System Components and Fabrication Details. 23830 Piping System Components and Fabrication Details 23831 Pipin
17、g System Components . 23832 Expansion and Flexibility . 30833 Design for Longitudinal Stress . 31834 Supports and Anchorage for Exposed Piping 33835 Anchorage for Buried Piping 34Tables831.4.2-1 Reinforcement of Welded Branch Connections, SpecialRequirements . 28832.2-1 Thermal Expansion or Contract
18、ion of PipingMaterials . 30iii832.5-1 Modulus of Elasticity for Carbon and Low AlloySteel . 31Chapter IV Design, Installation, and Testing 35840 Design, Installation, and Testing . 35841 Steel Pipe . 37842 Other Materials . 51843 Compressor Stations 58844 Pipe-Type and Bottle-Type Holders 61845 Cont
19、rol and Limiting of Gas Pressure 62846 Valves 68847 Vaults 69848 Customers Meters and Regulators 70849 Gas Service Lines . 71Tables841.1.6-1 Basic Design Factor, F . 39841.1.6-2 Design Factors for Steel Pipe Construction . 40841.1.7-1 Longitudinal Joint Factor, E . 41841.1.8-1 Temperature Derating F
20、actor, T, for Steel Pipe . 41841.1.11-1 Pipeline Cover Requirements 43841.2.3-1 Pipeline Field Cold Bend Requirements 45841.3.2-1 Test Requirements for Steel Pipelines and Mains toOperate at Hoop Stresses of 30% or More of theSpecified Minimum Yield Strength of the Pipe . 49841.3.3-1 Maximum Hoop St
21、ress Permissible During an Air or GasTest 50842.1.1-1 Standard Thickness Selection Table for DuctileIron Pipe . 52842.2.9-1 Nominal Values for Coefficients of Thermal Expansionof Thermoplastic Pipe Materials . 56844.3-1 Design Factors, F . 62844.3-2 Minimum Clearance Between Containers and FencedBou
22、ndaries . 62845.2.2-1 Maximum Allowable Operating Pressure for Steel orPlastic Pipelines or Mains . 63845.2.3-1 Maximum Allowable Operating Pressure for PipelinesOperating at 100 psig (690 kPa) or More . 63845.2.3-2 Maximum Allowable Operating Pressure for PipelinesOperating at Less Than 100 psig (6
23、90 kPa) 64Chapter V Operating and Maintenance Procedures 75850 Operating and Maintenance Procedures Affecting theSafety of Gas Transmission and DistributionFacilities 75851 Pipeline Maintenance . 77852 Distribution Piping Maintenance 83853 Miscellaneous Facilities Maintenance 86854 Location Class an
24、d Changes in Number of BuildingsIntended for Human Occupancy 89855 Pipeline Service Conversions 91856 Odorization . 91857 Uprating 92ivFigure851.4.1-1 Allowable Ripple Heights . 80Tables851.4.4-1 Wall Thickness for Unlikely Occurrence ofBurn-Through 81854.1-1 Location Class 89857.4-1 Wall Thickness
25、Allowance for Uprating a Ductile IronHigh-Pressure Main or System 94Chapter VI Corrosion Control . 95860 Corrosion Control General 95861 External Corrosion Control for Steel Pipelines 96862 Cathodic Protection Criteria . 98863 Operation and Maintenance of Cathodic ProtectionSystems 98864 Internal Co
26、rrosion Control 98865 Steel Pipelines in Arctic Environments . 99866 Steel Pipelines in High-Temperature Service . 100867 Stress Corrosion and Other Phenomena 101868 Cast Iron, Wrought Iron, Ductile Iron, and Other MetallicPipelines . 101Chapter VII Intentionally Left Blank . 102Chapter VIII Offshor
27、e Gas Transmission 103A800 Offshore Gas Transmission 103A801 General . 103A802 Scope and Intent 103A803 Offshore Gas Transmission Terms and Definitions 103A811 Qualification of Materials and Equipment . 104A814 Material Specifications 105A817 Conditions for the Reuse and Requalification of Pipe 105A
28、820 Welding Offshore Pipelines 105A821 General . 105A823 Qualification of Procedures and Welders . 105A825 Stress Relieving . 106A826 Inspection of Welds . 106A830 Piping System Components and Fabrication Details 106A831 Piping System Components . 106A832 Expansion and Flexibility . 106A834 Supports
29、 and Anchorage for Exposed Piping 107A835 Anchorage for Buried Piping 107A840 Design, Installation, and Testing . 107A841 Design Considerations 107A842 Strength Considerations . 108A843 Compressor Stations 111A844 On-Bottom Stability . 112A846 Valves 113A847 Testing . 113A850 Operating and Maintenan
30、ce Procedures Affecting theSafety of Gas Transmission Facilities 114A851 Pipeline Maintenance . 115A854 Location Class 115A860 Corrosion Control of Offshore Pipelines 115A861 External Corrosion Control 116A862 Cathodic Protection Criteria . 117A864 Internal Corrosion Control 117vTableA842.2.2-1 Desi
31、gn Factors for Offshore Pipelines, PlatformPiping, and Pipeline Risers 109Chapter IX Sour Gas Service . 118B800 Sour Gas Service 118B801 General . 118B802 Scope and Intent 118B803 Sour Gas Terms and Definitions . 118B813 Marking 119B814 Material Specifications 119B820 Welding Sour Gas Pipelines . 11
32、9B821 General . 119B822 Preparation for Welding . 119B823 Qualification of Procedures and Welders . 119B824 Preheating 119B825 Stress Relieving . 120B826 Welding and Inspection Tests 120B830 Piping System Components and Fabrication Details 120B831 Piping System Components . 120B840 Design, Installat
33、ion, and Testing . 120B841 Steel Pipe . 120B842 Other Materials . 121B843 Compressor Stations 121B844 Pipe-Type and Bottle-Type Holders 121B850 Additional Operating and MaintenanceConsiderations Affecting the Safety of Sour GasPipelines . 121B851 Pipeline Maintenance . 122B854 Location Class and Cha
34、nges in Number of BuildingsIntended for Human Occupancy 122B860 Corrosion Control of Sour Gas Pipelines . 122B861 External Corrosion Control for Steel Pipelines 124B864 Internal Corrosion Control 124B867 Stress Corrosion and Other Phenomena 124TablesB850.1-1 100-ppm ROE . 123B850.1-2 500-ppm ROE . 1
35、23B850.1-3 Metric Example for 100-ppm ROE . 123B850.1-4 Metric Example for 500-ppm ROE . 123AppendicesMandatory Appendix A References 125Mandatory Appendix B Numbers and Subjects of Standards and SpecificationsThat Appear in Mandatory Appendix A . 130Nonmandatory Appendix C Publications That Do Not
36、Appear in the Code orMandatory Appendix A 131Mandatory Appendix D Specified Minimum Yield Strength for Steel PipeCommonly Used in Piping Systems . 134Mandatory Appendix E Flexibility and Stress Intensification Factors 137Mandatory Appendix F Extruded Headers and Welded Branch Connections 143Mandator
37、y Appendix G Testing of Welders Limited to Work on Lines Operatingat Hoop Stresses of Less Than 20% of the SpecifiedMinimum Yield Strength 150Mandatory Appendix H Flattening Test for Pipe . 151Mandatory Appendix I End Preparations for Buttwelding . 152Nonmandatory Appendix J Commonly Used Conversion
38、 Factors 161viMandatory Appendix K Criteria for Cathodic Protection . 165Nonmandatory Appendix L Determination of Remaining Strength of CorrodedPipe 167Nonmandatory Appendix M Gas Leakage Control Criteria 168Nonmandatory Appendix N Recommended Practice for Hydrostatic Testing ofPipelines in Place .
39、175Nonmandatory Appendix O Preparation of Technical Inquiries . 177Nonmandatory Appendix P Nomenclature for Figures . 178Mandatory Appendix Q Scope Diagrams . 179Nonmandatory Appendix R Estimating Strain in Dents 182Index 183viiFOREWORDThe need for a national code for pressure piping became increasi
40、ngly evident from 1915 to1925. To meet this need, the American Engineering Standards Committee later changed to theAmerican Standards Association, now the American National Standards Institute (ANSI) initiatedProject B31 in March 1926 at the request of the American Society of Mechanical Engineers an
41、dwith that Society as sole sponsor. After several years of work by Sectional Committee B31 andits subcommittees, a first Edition was published in 1935 as an American Tentative Standard Codefor Pressure Piping.A revision of the original tentative standard began in 1937. Several more years of effort w
42、eregiven to securing uniformity among sections, eliminating divergent requirements and discrepan-cies, keeping the Code abreast of current developments in welding technique, calculating stresscomputations, and including reference to new dimensional and material standards. During thisperiod, a new se
43、ction on refrigeration piping was prepared in cooperation with the AmericanSociety of Refrigeration Engineers and complemented the American Standard Code for MechanicalRefrigeration. This work culminated in the 1942 American Standard Code for Pressure Piping.Supplements 1 and 2 of the 1942 Code, whi
44、ch appeared in 1944 and 1947, respectively, introducednew dimensional and material standards, a new formula for pipe wall thickness, and morecomprehensive requirements for instrument and control piping. Shortly after the 1942 Code wasissued, procedures were established for handling inquiries requiri
45、ng explanation or interpretationof Code requirements and for publishing such inquiries and answers in Mechanical Engineeringfor the information of all concerned.By 1948, continuing increases in the severity of service conditions combined with the develop-ment of new materials and designs to meet the
46、se higher requirements warranted more extensivechanges in the Code than could be provided from supplements alone. The decision was reachedby the American Standards Association and the sponsor to reorganize the sectional committeeand its several subcommittees and to invite the various interested bodi
47、es to reaffirm their represen-tatives or to designate new ones.Because of the wide field involved, between 30 and 40 different engineering societies, govern-ment bureaus, trade associations, institutes, and similar organizations had one or more representa-tives on the sectional committee, plus a few
48、 “members-at-large” to represent general interests.Code activities were subdivided according to the scope of the several sections. General directionof Code activities rested with the Standards Committee officers and an executive committee,membership of which consisted principally of Standards Commit
49、tee officers and section chairmen.Following its reorganization in 1948, Standards Committee B31 made an intensive review ofthe 1942 Code that resulted in(a) a general revision and extension of requirements to agree with present-day practice(b) the revision of references to existing dimensional standards and material specifications andthe addition of references to the new ones(c) the clarification of ambiguous or conflicting requirementsA revision was presented for letter ballot vote of Standards Committee B31. Following approvalby this body, the project was approved by the sponsor
