ASME_B16.20-2007.pdf

ASME B16.20-2007(Revision of ASME B16.20-1998)Metallic Gasketsfor Pipe FlangesRing-Joint,Spiral-Wound,andJacketedAN AMERICAN NATIONAL STANDARDThe American Society ofASMEMechanical EngineersSETTING THE STANDARDNo reproducion or neworking permised wihout cense ferom IHSFOREWORDRing-joint gaskets and grooves probably originated in the boiler field,where they were usedin various forms for manhole covers,autoclaves,and other closures;however,it was in the oilindustry(both in the production and refining of oil)that they received the greatest recognitionand were developed into their present form.Their use expanded steadily as temperatures andpressures were increased in steam plants.Tests examining their application in flanges and valveswere conducted as early as 1928.In June 1936,the American Petroleum Institute(API)issued Tentative Standard 5-G-3 on Ring-Joints for Steel Flanges and Flange Unions for use with API Tubular Goods.This standard wasknown as API Specification 6B,Ring-Joint Flanges.Following the acceptance of ring-joints forflanges and valves by API and the issuance of their standard,ASA B16e on Steel Pipe Flangesand Flanged Fittings was revised to include them,and the 1939 edition included standarddimensions for a full line of ring-joint flanges based on the API standard.Development workcontinued and API formulated Standard 6E,Specification for Wellhead Equipment,whichincluded ring-joints not covered in ASA B16e-1939.In 1949,the American Standards Association(ASA),Sectional Committee B16,Subcommittee3,Steel Flanges and Flanged Fittings,assembled the available information on ring-joint gasketsinto a single standard.ASA approval was granted on April 30,1952,with the designation ASAB16.20-1952.An updated version was submitted and ASA approval was granted on April 4,1955,with thedesignation ASA B16.20-1955.Ring gaskets for Class 900(900 lb at that time)in sizes NPS 26through 36 were added and ASA approval was granted on April 2,1956.The standard wasreviewed in 1962 and approval was granted by the ASA on April 25,1963.The standard was again reviewed and approval was granted by the American National Stan-dards Institute(ANSI)on April 25,1973,with the designation of an American National Standard.API requested that ASME convert their gasket standard,API 601,into an ASME AmericanNational Standard.As a result of that request,the standard was expanded to include requirementsfor spiral-wound and jacketed gaskets that were formerly listed in API 601,7th edition,1988.Also,ring-joint groove dimensions were not included,because they were included in ASME/ANSI B16.5-1988,titled Pipe Flanges and Flanged Fittings,and ASME B16.47-1990,titled LargeDiameter Steel Flanges.The 1993 edition was approved by the B16 Standards Committee and,following approval byASME,approval by ANSI was given on January 22,1993,with the designation ASME B16.20-1993.In the 1998 edition of ASME B16.20,reference standards were updated,a quality systemprogram annex was added,inner ring inside diameters for spiral-wound gaskets were revised,and several editorial revisions were made.Following approval by ASME B16 Subcommittee Gand the B16 Main Committee,ANSI approved this American National Standard on November20,1998.In 2007,the standard adopted metric dimensions as an independent standard to the U.S.Customary units;Mandatory Appendix I has been added to cover dimensional tables in U.S.Customary units.Following approval by B16 Subcommittee G,the Standards Committee,andASME,ANSI approved this American National Standard on October 19,2007.ivee-Petrofac Intemasonal Lid 5954785001No reproduction or networking permised without lcense from IHSRo0172090666