2013_2018.pdf

AN AM E R IC AN NAT IO NAL STANDARD ASME B1.20.1-2013Revision of ASME B1.20.1-1983(R2006)Pipe Threads,General Purpose(Inch)REAFFIRMED 2018ASME B1.20.1-2013Revision of ASME B1.20.1-1983(R2006)Pipe Threads,General Purpose(Inch)AN AMERICAN NATIONAL STANDARDTwo Park Avenue New York,NY 10016 USADate of Issuance:November 15,2013This Standard will be revised when the Society approves the issuance of a new edition.There willbe no written interpretations of the requirements of this Standard issued to this edition.PeriodicallycertainactionsoftheASMEB1CommitteemaybepublishedasCases.Casesarepublishedon the ASME Web site under the Committee Pages at http:/cstools.asme.org/as they are issued.Errata to codes and standards may be posted on the ASME Web site under the Committee Pages toprovide corrections to incorrectly published items,or to correct typographical or grammatical errorsin codes and standards.Such errata shall be used on the date posted.The Committee Pages can be found at http:/cstools.asme.org/.There is an option available toautomatically receive an e-mail notification when errata are posted to a particular code or standard.ThisoptioncanbefoundontheappropriateCommitteePageafterselecting“Errata”inthe“PublicationInformation”section.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards.The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate.The proposed code or standard was madeavailable forpublic review andcomment thatprovides an opportunityfor additional publicinput from industry,academia,regulatory agencies,and the public-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 anyitems mentioned in this document,and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent,nor assumes any such liability.Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights,and the risk of infringement of such rights,isentirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.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 2013 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword.ivCommittee Roster.vCorrespondence With the B1 Committee.vi1Introduction.12American National Standard Pipe Thread Form.23Specification for Taper Pipe Threads,NPT.44Specifications for Internal Straight Threads in Pipe Couplings,NPSC.135Specifications for Railing Joint Taper Pipe Threads,NPTR.146Specifications for Straight Pipe Threads for Mechanical Joints;NPSM,NPSL.167Gages and Gage Tolerances for American National Standard Taper PipeThreads,NPT.19Figures1Root,Crest,and Flank Engagement,NPT.22Basic Form of American National Standard Taper Pipe Thread,NPT.33American National Standard Taper Pipe Thread Notation.64Gaging External Taper Threads With L1Ring Gage.105Gaging of Chamfered Threads.116Gaging Internal Taper Threads With L1Plug Gage.127NPT Standard Taper Pipe Thread Plug and Ring Gages.208Suggested Form of Gage Thread.21Tables1Limits on Crest and Root Truncation of American National Standard Externaland Internal Taper Pipe Threads,NPT.52Basic Dimensions of American National Standard Taper Pipe Thread,NPT.83Tolerances on Taper,Lead,and Angle of Pipe Threads,NPT.104Dimensions,Internal Straight Threads in Pipe Coupling,NPSC.145Dimensions of External and Internal Taper Pipe Threads for RailingJoints,NPTR.156Dimensions of External and Internal Straight Pipe Threads for Fixtures,NPSM.177Dimensions,External and Internal Straight Pipe Thread for LocknutConnections,NPSL.188Basic Dimensions of Threaded Gages for American National Standard Taper PipeThreads,NPT.229Working Gage Tolerances for American National Standard Taper PipeThread,NPT.2310Diameter Equivalent of Variation in Half Included Angle of Thread for Toolsand Gages.2511Diameter Equivalent of Variation in Lead for Tools and Gages.26Nonmandatory AppendicesAThe Turns of Engagement Method of Gaging Product Threads.27BTap Drill Sizes.28CThread Types and Corresponding Gages and Gaging.29iiiFOREWORDIn 1973,American National Standards Committee B2,which had formerly been responsible forpipe thread standards,was absorbed by American National Standards Institute(ANSI)StandardsCommittee