TB-1_Edtn_2009.pdf

ASME PTB-1-2009ASME Section VIII Division 2Criteria and CommentaryCopyrighted 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.Copyright 2009 by the American Society of Mechanical Engineers.No reproduction may be made of this material without written consent of ASME.c PTB-1-2009 ASME Section VIII-Division 2 Criteria and Commentary David A.Osage,P.E.The Equity Engineering Group,Inc.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.Copyright 2009 by the American Society of Mechanical Engineers.No reproduction may be made of this material without written consent of ASME.cDate of Issuance:June 10,2009 This document was prepared as an account of work sponsored by ASME Pressure Technology Codes and Standards(PTCS)through the ASME Standards Technology,LLC(ASME ST-LLC).Neither ASME,the author,nor others involved in the preparation or review of this document,nor any of their respective employees,members or persons acting on their behalf,makes any warranty,express or implied,or assumes any legal liability or responsibility for the accuracy,completeness or usefulness of any information,apparatus,product or process disclosed,or represents that its use would not infringe upon privately owned rights.Reference herein to any specific commercial product,process or service by trade name,trademark,manufacturer or otherwise does not necessarily constitute or imply its endorsement,recommendation or favoring by ASME or others involved in the preparation or review of this document,or any agency thereof.The views and opinions of the authors,contributors and reviewers of the document expressed herein do not necessarily reflect those of ASME or others involved in the preparation or review of this document,or any agency thereof.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 assume 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 is the registered trademark of The American Society of Mechanical Engineers.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 2009 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All rights reserved Printed in the 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.Copyright 2009 by the American Society of Mechanical Engineers.No reproduction may be made of this material without written consent of ASME.cPTB-1-2009 iii FOREWORD In 1998 the ASME Boiler and Pressure Vessel Standards Committee authorized a project to rewrite the ASME B&PV Code,Section VIII,Division 2.This decision was made shortly after the design margin on specified minimum tensile strength was lowered from 4.0 to 3.5 in Section I and Section VIII,Division 1.ASME saw the need to update Section VIII,Division 2 to incorporate the latest technologies and to be more competitive.In lieu of revising the existing standard,the decision was made to perform a clean sheet rewrite.By doing so it was felt that,not only could the standard be modernized with regard to the latest technical advances in pressure vessel construction,but it could be structured in a way to make it more user-friendly for both users and the committees that maintain it.Much new ground was broken in the development of the new Section VIII,Division 2,including the process taken to write the new standard.Traditionally,development of new standards by ASME is carried out by volunteers who serve on the different committees responsible for any given standard.Depending upon the complexity of the standard,the development of the first drafts may take up to 15 years to complete based on past history.The prospect of taking 15 or more years to develop VIII-2 was unacceptable to ASME and the volunteer leadership.The decision was made to subcontract the development of the draft to th