ASME_B2.1-1968.pdf

BP2.5 B2.L 0047024 000084L 178 USA STANDARD Pip e T hr eads(Except Dry seaI)USAS B2.1-1968 Specifications,Dimens ions,and Gaging for Ta per and Straight Pipe T hreads Including Certain Special Applications 3pon50,The Am er ica n Society of Mechanica l Engineer s Yl,d$X,d 6y THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS United Engineering Center New York,N.Y.1 O01 7 345 East 47th Street BP25 82.1 0049024 0000842 004 m USA STANDARD This USA Standard is one of nearly 3000 standards approved as American Standards by the American Standards Association.On August 24,1966,the ASA was reconstituted as the United States of America Standards Institute.Standards approved as American Standards are now designated U SA Standards.There is no change in their index identification or technical content.Any part of this standard may be quoted.Credit lines should read:“Extracted from USA Standard Pipe Threads(Except Dryseal)(USAS B2.1-1968)with the permission of the publisher,The American Society of Mechanical Engineers,United Engineering Center,345 East 47th Street,New York,N.Y.10017.”Copyright.,1969.by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS Pr in ted in U.S.A.II BP25 B2.1 0049024 0000843 T40 FOREWORD In 1913 a Committee on the Standardization of Pipe Threads was organized for the purpose of re-editing and expanding the Briggs Standard.The American Gas Association and The American Society of Mechanical Engineers served as joint sponsors.After six years of work,this com-mittee completed the revised standard for taper pipe thread which was published in the ASM E“Transactions”of 1919,and was approved as an American Standard by the American Engineering Standards Committee,later named the American Standards Association in December 1919.It was the first standard to receive this designation under the A SA procedure,and was later published in pamphlet form.In the years which followed,the need for a further revision of this American Standard became evident as well as the necessity of adding to it the recent developments in pipe threading practice.Accordingly,the Sectional Committee on the Standardization of Pipe Threads,B2,was organized in 1927 under the joint sponsorship of the A.G.A.and the ASME.During the f ollowing 15 years,several meetings were held leading to approval by the members of the Sectional Committee,of the April 1941 draft.The revision was approved by the sponsors and ASA and published as an American Standard in October,1942.Shortly after publication of the 1942 standard,the Committee undertook preparation of a com-plete revision.The text and tables were rearranged and expanded to include Dryseal pipe threads,and an extensive appendix was added to provide additional data on the application of pipe threads and to record in abbreviated form the several special methods which were established for gaging some of the various applications of pipe threads.The resulting proposal was approved by letter ballot of the Sectional Committee.Following its acceptance by the sponsor bodies,the draft was submitted to the American Standards Association and designated an American Standard on December 11,1945.At a subsequent meeting of the Sectional Committee it was agreed that for the convenience of users,the standards covering Dryseal pipe threads should be published under separate cover.Consequently,the section included in A SA B2.1-1945 on Dryseal pipe threads was deleted fr om the 1960 revision to that standard and used as a basis for the development of a separate proposal for Dryseal pipe threads.The text and tables were expanded to completely document the various series threads and gages,and appendices covering formulas,drilled hole sizes and special series threads were added.The E,internal diameter and the LI hand type engagements for the/,and?4 inch sizes were revised to correct for a disproportionate number of threads for hand tight engage-ment.This proposal was approved by letter ballot vote of the Sectional Committee and submitted t o the A.G.A.and the ASME.Following approval by the sponsor organizations,it was approved by the American Standards Association on April 29,1960,and designated as ASA B2.1-1960,Pipe Threads(Except Dry seal).The present revision of this standard constitutes a general updating.In line with their current policy,the A GA.has wi thd rawn sponsorship of this standard,while remaining active in the work of the standards committee.In compliance with the rules of the United States of America Standards Institute(formerly ASA)the previously designated Sectional Committees are now called Standards Committees.Following approval b y the Standards Committee B2 and the sponsor,ASME,the revision was approved by the United States of America Standards Institute on November 29,196 8.III BP25 B2.L 0049024 0000844 987 HISTORICAL NOTE The USA(American)Standard for Pipe Threads,originally known as the Briggs Standard,was formulated by Mr.Robert Briggs.For several years around 1862 Mr.Briggs was superintendent of the Pascal