ASME_B16-42-1998.pdf

Copyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.#+8 The American Society of Mechanical Engineers AN AMERICAN NATIONAL STANDARD DUliTllElRON PIPEFLANGESAND FLANGED FlTTlNbS Classes 150 and 300 ASIVIE B16.42-1 UN8(Revision olASMVANSlBlB.42-1987)Copyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.Date of Issuance:April 26,1999 The 1998 edition of this Standard is being issued with an automatic addenda subscription service.The use of addenda allows revisions made in response to public review comments or committee actions to be published on a regular yearly basis;revisions published in addenda will become effective six months after the Date of Issuance of the addenda.The next edition of this Standard is scheduled for publication in 2003.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Standard.The interpretations will be included with the above addenda service.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 National Standards.The Standards Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate.The proposed code or standard was made available for public review and comment,which provides an opportunity for additional public input 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 any items mentioned in this document,and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent,nor assumes any such liability.Users of a code or standard are expressly advised that determination of the validity of any such patent rights,and the risk 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 interpreted as government or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations issued in accordance with governing ASME procedures and policies which precludes the issuance of interpretations by individual volunteers.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 Engineers Three Park Avenue,New York,NY 10016-5990 Copyright 0 1999 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A.Copyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.FOREWORD(This Foreword is not part of ASME B16.42-1998.)In 1921,the American Engineering Standards Committee,later the American Standards Association(ASA),now the American National Standards Institute(ANSI),authorized the organization of a Sectional Committee on the Standardization of Pipe Flanges and Flanged Fittings,with the following organizations as joint sponsors:Heating,Piping,and Air Conditioning Contractors National Association(later the Mechanical Contractors Association of America,MCAA),Manufacturers Standardization Society of the Valves and Fittings Industry(MSS),and The American Society of Mechanical Engineers(ASME).Cast iron flanges and flanged fittings are within the scope of Subcommittee No.1(now Subcommittee A),with standards approved by ASA as early as 1928.In 1957,piping components of ductile iron(also called nodular iron and,in Europe,spheroidal graphite iron)first appeared in the market.Controversy immediately developed over proper pressure-temperature ratings,and this was further aggravated by the use of casting patterns for both gray iron and carbon steel for producing the components.Conflicting philosophies,which emerged from that controversy,thwarted efforts by MSS to develop standard practices in the early 1960s;the conflicts persisted during a study of ratings,starting in 1966 by American National Standards Committee B16(as the Sectional Committee was called after reorganization of ASA as ANSI).The conflict continued to delay acceptance and approval of this Standard,which ultimately originated with a draft developed by MSS(taking advantage of earlier efforts)and submitted to Subcommittee A in 1977.Combining tha