ASME_B16.21-2005.pdf

ASME B16.21-2005(Revision of ASME B16.21-1992)Nonmetallic FlatGaskets forPipe FlangesAN AMERICAN NATIONAL STANDARDThe American Society ofMechanical EngineersThree Park Avenue.New York,NY 10016No roproduction or notworking permitled without liconso from IHSNot for ResaloCONTENTSForeword.ivCommittee Roster.。.Correspondence With the B16 Committeey1 Scope。1Types and Sizes.23Materials4Dimensions and Tolerances.15 Markings,。.。,Tables1Gasket Dimensions for ASME B16.1 Class 25,Cast Iron Pipe Flanges andFlanged Fittings32Gasket Dimensions for ASME B16.1 Class 125,Cast Iron Pipe Flanges andFlanged Fittings03Flat Ring Gasket Dimensions for ASME B16.1 Class 250,Cast Iron Pipe Flangesand Flanged Fittings.4 Gasket Dimensions for ASME B16.5 Class 150,Pipe Flanges and Flanged Fittings45Flat Ring Gasket Dimensions for ASME B16.5 Pipe Flanges and Flanged Fittings,Classes300,400,600,and900.46Full Face Gasket Dimensions for ASME B16.24,Cast Copper Alloy Pipe Flangesand Flanged Fittings,Classes 150 and 300.57Flat Ring Gasket Dimensions for ASME B16.47 Series A,Large Diameter SteelFlanges,Classes150,300,400,and600.5Flat Ring Gasket Dimensions for ASME B16.47 Series B,Large Diameter SteelFlanges,Classes75,150,300,400,and600.69Full Face Gasket Dimensions for MSS SP-51 Class 150LW,Corrosion-ResistantCast Flanges and Flanged Fittings.6Mandatory AppendicesIDimensions of Gaskets in U.S.Customary Units.II References.12Nonmandatory AppendixA Quality System Program13i进Eow曲AS/ENo roproduction or notworking permitled without liconso from IHSNot for ResaloFOREWORDBefore this standard was issued,the individual sizes of gaskets were made to many differentsets of dimensions,based on different concepts of adaptation and functional use on the part ofconsumers as well as manufacturers.In some cases dimensions were shown in American Stan-dards.To standardize gasket sizes,the Standards and Specifications Committee of the Mechani-cal Packing Association started work on a standard for nonmetallic or cut gaskets for bronze,iron,and steel pipe flanges.Dimensions of gaskets being used were collected,and a basic design philosophy for sizing wasformulated by the committee.This was the result of extensive field research experience and ac-cepted standard user requirements.The procedure followed was to dimension the gasket for eachtype and size of flange so as to prevent the gasket from projecting into the line of flow.Dimen-sional tolerances of standard pipe flanges and fittings as to I.D.,O.D.,and bolting were all con-sidered.Suggested dimensional standards were tabulated and distributed for industry comment.Afterseveral revisions,a final draft,dated September 15,1948,was approved by the Mechanical Pack-ing Association for submission as an American Standard.Sectional Committee(B16)on the Standardization of Pipe Flanges and Fittings was organizedin 1921 under the procedure of the American Standards Association,with the Heating,Piping,and Air Conditioning ContractorsNational Association,ManufacturersStandardization Societyof the Valve and Fittings Industry,and the American Society of Mechanical Engineers as jointsponsors.Sectional Committee B16 received the proposal on May 9,1949,and assigned it to a joint groupof Subcommittees 1 and 3.The ManufacturersStandardization Society was also consulted as theproposal included gaskets for bronze flanges made to their Standard Practice SP-2.This joint groupoffered a revision of the original design concept for sizing,which was acceptable to the Mechani-cal Packing Associations Committee(now the Fluid Sealing Association).The Standard was ap-proved as an American Standard on December 5,1951,with the designation ASA B16.21-1951.In 1961,the Standard was reviewed by the members of Subcommittee No.7 on Gaskets andproposals for revision and updating the Standard were agreed upon.The American StandardsAssociation granted approval of the revision on March 20,1962 following sectional committeeand sponsor approval.In the mid-1960s,work had begun on a revision.The revision became a complete rewrite andincluded gaskets for API Std 605,MSS SP-44 and SP-51,as well as complete metric equivalentsfor all dimensions.Following its approval by the B16 Standards Committee and Co-Secretariatorganizations,this Standard was approved as an American National Standard by ANSI on May2,1978.In 1982,American National Standards Committee B16 was reorganized as an ASME Commit-tee operating under procedures accredited by ANSI.In 1989,general revisions had begun to reflect the current size ranges covered by the corre-sponding flange standard.Gasket dimensions for tongue and groove,male and female RatingClasses above 900 were deleted because a survey indicated these nonmetallic gaskets were al-most never used for these joints.Tolerances to the dimensions were added.Following approval by the Standards Committee and ASME,approval as an American Na-tional Standard was given by ANSI on March 16,1992,with the new designation ASME B16.21-1992.In 2005,the Standard adopted metric(SI)dimensions.Following approval by the B16 Sub-committee G,the B16 Standards Committee,and ASME,ANSI approved this American NationalStandard on March 16,2005.All requests for interpretation or suggestions for revisions should be sent to the Administra-tive Secretary B16,The American Society of Mechanical Engineers,Three Park Avenue,New York,NY10016-5990.ivso with ASMENo roproduction or notworking permitled without liconso from IHSNot for Resale