ASME_B31.8-2020.pdf

Gas Transmission and Distribution Piping SystemsASME Code for Pressure Piping,B31AN INTE R NAT IO NAL PIPING CO D EASME B31.8-2020(Revision of ASME B31.8-2018)ASME B31.8-2020(Revision of ASME B31.8-2018)Gas Transmissionand DistributionPiping SystemsxASME Code for Pressure Piping,B31AN INTERNATIONAL PIPING CODETwo Park Avenue New York,NY 10016 USAxDate of Issuance:May 31,2021The next edition of this Code is scheduled for publication in 2022.This Code will become effective 6 months after the Date ofIssuance.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Code.Interpretations arepublished on the Committee web page and under http:/go.asme.org/Interpretations.Periodically certain actions of theASME B31 Committee may be published as Cases.Cases are published on the ASME website under the B31 CommitteePage at http:/go.asme.org/B31committee as they are issued.Errata to codes and standards may be posted on the ASME website under the Committee Pages of the associated codes andstandardstoprovidecorrectionstoincorrectlypublisheditems,ortocorrecttypographicalorgrammaticalerrorsincodesandstandards.Such errata shall be used on the date posted.The B31 Committee Page can be found at http:/go.asme.org/B31committee.The associated B31 Committee Pages for eachcode and standard can be accessed from this main page.There is an option available to automatically receive an e-mailnotification when errata are posted to a particular code or standard.This option can be found on the appropriate CommitteePage after selecting“Errata”in the“Publication Information”section.ASME is the registered trademark of The American Society of Mechanical Engineers.This international code or standard was developed under procedures accredited as meeting the criteria for American National StandardsanditisanAmericanNationalStandard.TheStandardsCommitteethatapprovedthecodeorstandardwasbalancedtoassurethatindividualsfromcompetentandconcernedinterestshavehadanopportunitytoparticipate.Theproposedcodeorstandardwasmadeavailableforpublicreviewandcommentthatprovidesanopportunityforadditionalpublicinputfromindustry,academia,regulatoryagencies,andthepublic-at-large.ASME does not“approve,”“rate,”or“endorse”any item,construction,proprietary device,or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in thisdocument,anddoesnotundertaketoinsureanyoneutilizingastandardagainstliabilityforinfringementofanyapplicableletterspatent,norassumeanysuchliability.Usersofacodeorstandardareexpresslyadvisedthatdeterminationofthevalidityofanysuchpatentrights,andtherisk of infringement of such rights,is entirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted as government or industryendorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the established ASME proceduresand policies,which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,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 2021 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword.ixCommittee Roster.xiCorrespondence With the B31 Committee.xivIntroduction.xviSummary of Changes.xviiiGeneral Provisions and Definitions.1801General.1802Scope and Intent.1803Piping Systems Definitions.2804Piping Systems Component Definitions.5805Design,Fabrication,Operation,and Testing Terms and Definitions.7806Quality Assurance.13807Training and Qualification of Personnel.13Chapter IMaterials and Equipment.15810Materials and Equipment.15811Qualification of Materials and Equipment.15812Materials for Use in Low-Temperature Applications.16813Marking.16814Material Specifications.16815Equipment Specifications.17816Transportation of Line Pipe.17817Conditions for the Reuse of Pipe.17Chapter IIWelding.20820Welding.20821General.20822Preparation for Welding.20823Qualification of Procedures and Welders.21824Preheating.21825Stress Relieving.21826Weld Inspection Requirements.22827RepairorRemovalofDefectiveWeldsinPipingIntendedtoOperateatHoopStressLevelsof20%or More of the Specified Minimum Yield Strength.23Chapter IIIPiping System Components and Fabrication Details.24830General.24831Piping System Components.24832Expansion and Flexibility.31833Design for Longitudinal Stress.32834Supports and Anchorage for Exposed Piping.35iii835Anchorage for Buried Piping.36836Liquid Removal Equipment.36Chapter IVDesign,Installation,and Testing.37840Design,Installation,and Testing.37841Steel Pipe.39842Other Materials.53843Compressor Stations.61844Pipe-Type and Bottle-Type Holders.64845Control and Limiting of Gas Pressure.65846Val