1、AN AM E R IC AN NAT IO NAL STANDARDASME B16.4-2021(Revision of ASME B16.4-2016)Gray IronThreadedFittingsClasses 125 and 250ASME B16.4-2021(Revision of ASME B16.4-2016)Gray IronThreadedFittingsxClasses 125 and 250AN AMERICAN NATIONAL STANDARDTwo Park Avenue New York,NY 10016 USAxDate of Issuance:Febr
2、uary 1,2022The next edition of this Standard is scheduled for publication in 2026.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Standard.Periodically certainactionsoftheASMEB16CommitteemaybepublishedasCases.CasesandinterpretationsarepublishedontheAS
3、MEwebsiteunder the Committee Pages at http:/cstools.asme.org/as they are issued.Errata to codes and standards may be posted on the ASME website under the Committee Pages to provide corrections toincorrectlypublisheditems,ortocorrecttypographicalorgrammaticalerrorsincodesandstandards.Sucherratashallb
4、eusedon the date posted.TheCommitteePagescanbefoundathttp:/cstools.asme.org/.Thereisanoptionavailabletoautomaticallyreceiveane-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
5、Information”section.ASME is the registered trademark of The American Society of Mechanical Engineers.ThiscodeorstandardwasdevelopedunderproceduresaccreditedasmeetingthecriteriaforAmericanNationalStandards.TheStandardsCommitteethatapprovedthecodeorstandardwasbalancedtoassurethatindividualsfromcompete
6、ntandconcernedinterestshavehadanopportunityto participate.The proposed codeorstandardwasmadeavailable forpublic reviewandcommentthatprovidesanopportunityfor additional public input from industry,academia,regulatory agencies,and the public-at-large.ASME does not“approve,”“rate,”or“endorse”any item,co
7、nstruction,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,n
8、orassumeanysuchliability.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 inte
9、rpreted 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 docum
10、ent 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 2022 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedCON
11、TENTSForeword.ivCommittee Roster.viCorrespondence With the B16 Committee.viiSummary of Changes.ixList of Changes in Record Number Order.x1Scope.12General.13PressureTemperature Ratings.14Size.25Marking.26Material.27Dimensions and Tolerances.28Threading.39Ribs.310Plugs,Bushings,and Locknuts.311Face Be
12、vel.312Coatings.3Mandatory AppendixIReferences.14Nonmandatory AppendixAQuality System Program.15Figures4.2-1Identification of Reducing Fittings.28-1Gaging of Chamfered Internal Threads.13Tables3-1PressureTemperature Ratings.27.1-1Dimensions of Class 125 90-deg and 45-deg Elbows,Tees,and Crosses(Stra
13、ight Sizes).47.1-2Dimensions of Class 125 90-deg Elbows and Crosses(Reducing Sizes).57.1-3Dimensions of Class 125 Tees(Reducing Sizes).77.1-4Dimensions of Class 125 Caps,Reducing Couplings,and Closed-and Open-Pattern Return Bends107.1-5Dimensions of Class 250 90-deg and 45-deg Elbows,Tees,and Crosse
14、s(Straight Sizes).127.3-1Inspection Tolerances.13iiiFOREWORDInthespringof1921,whentheunificationand extensionoftheflangedand threadedfittingsstandardsinforceintheUnitedStatesseemeddesirable,theAmericanEngineeringStandardsCommitteesubsequentlytheAmericanStandardsAssociation(ASA)and currently the Amer
15、ican National Standards Institute(ANSI)authorized the organization of aSectional Committee onthe Standardization of Pipe Flanges and Flanged Fittings.The following organizations served asjointsponsors:Heating,Piping,andAirConditioningContractorsNationalAssociation(latertheMechanicalContractorsAssoci
16、ation of America),Manufacturers Standardization Society of the Valve and Fittings Industry,and the AmericanSociety of Mechanical Engineers.AtthesecondmeetingoftheSectionalCommitteeheldinNewYorkonDecember16,1921,areportwassubmittedbytheSubcommitteeonThreadedFittings.ThereportindicatedclearlythatgoodprogresswasalreadybeingmadetowardthedevelopmentofanAmericanStandardforcastironthreadedfittingsintendedforservicesof125-lband250-lbsteampressure.The review of the proposals of the manufacturers Committe
