_RP_621-2018.pdf

Reconditioning of Metallic Gate,Globe,and Check ValvesAPI RECOMMENDED PRACTICE 621FOURTH EDITION,OCTOBER 2018Special NotesAPI publications necessarily address problems of a general nature.With respect to particular circumstances,local,state,and federal laws and regulations should be reviewed.Neither API nor any of APIs employees,subcontractors,consultants,committees,or other assignees make any warranty or representation,either express or implied,with respect to the accuracy,completeness,or usefulness of the information contained herein,or assume any liability or responsibility for any use,or the results of such use,of any information or process disclosed in this publication.Neither API nor any of APIs employees,subcontractors,consultants,or other assignees represent that use of this publication would not infringe upon privately owned rights.API publications may be used by anyone desiring to do so.Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them;however,the Institute makes no representation,warranty,or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict.API publications are published to facilitate the broad availability of proven,sound engineering and operating practices.These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized.The formulation and publication of API publications is not intended in any way to inhibit anyone from using any other practices.Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard.API does not represent,warrant,or guarantee that such products do in fact conform to the applicable API standard.All rights reserved.No part of this work may be reproduced,translated,stored in a retrieval system,or transmitted by any means,electronic,mechanical,photocopying,recording,or otherwise,without prior written permission from the publisher.Contact the Publisher,API Publishing Services,1220 L Street,NW,Washington,DC 20005.Copyright 2018 American Petroleum InstituteForewordNothing contained in any API publication is to be construed as granting any right,by implication or otherwise,for the manufacture,sale,or use of any method,apparatus,or product covered by letters patent.Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.The verbal forms used to express the provisions in this document are as follows.Shall:As used in a standard,“shall”denotes a minimum requirement in order to conform to the standard.Should:As used in a standard,“should”denotes a recommendation or that which is advised but not required in order to conform to the standard.May:As used in a standard,“may”denotes a course of action permissible within the limits of a standard.Can:As used in a standard,“can”denotes a statement of possibility or capability.This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard.Questions concerning the interpretation of the content of this publication or comments and questions concerning the procedures under which this publication was developed should be directed in writing to the Director of Standards,American Petroleum Institute,1220 L Street,NW,Washington,DC 20005.Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the director.Generally,API standards are reviewed and revised,reaffirmed,or withdrawn at least every five years.A one-time extension of up to two years may be added to this review cycle.Status of the publication can be ascertained from the API Standards Department,telephone(202)682-8000.A catalog of API publications and materials is published annually by API,1220 L Street,NW,Washington,DC 20005.Suggested revisions are invited and should be submitted to the Standards Department,API,1220 L Street,NW,Washington,DC 20005,standardsapi.org.iiiContentsPage1Scope.12Normative References .13Terms and Definitions.24Owner Access and Responsibilities.35Inspection,Identification,and Disassembly of Valves.35.1General.35.2Identification Number.45.3Traveler Documents.45.4Disassembly and Cleaning of Valves.46Repair of Valve Parts.56.1General.56.2Inspection of Valve Parts.66.3Handwheel Nut.66.4Handwheel.66.5Yoke.76.6Stem Nut and Stem Nut Housing.76.7Stem Nut Retainer.76.8Packing Gland Flange.76.9Packing Gland.76.10 Backseat Bushing.86.11 Body and Bonnet.86.12 Body Guides .136.13 Body Seat Ring(s).136.14 Wedge Guides.146.15 O