ISO INTERNATIONAL STANDARD 7121 Third edition 2016-04-15 Steel ball valves for general-purpose industrial applications Robinets en acier a tournant sphérique pour les applications industriellesgénerales Reference number ISO 7121:2016(E) ISO International Organization for Standardization ISee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 @IS02016 vided by IHS under I Not for Resale, 2016/7/20 02:56:35 No reproduction or networking permitted without license from IHS IS0 7121:2016(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Licensee-ZHEJIANG INST OF STANDARDIZzRoISQ6 - All rights reserved Not for Resale, 2016/7/20 02:56:35 networking permited without license from IHS IS0 7121:2016(E) Contents Page Foreword ..V Introduction. ...vi 1 Scope. 2 Normative references 3 Terms and definitions 4 Pressure/temperature ratings .3 4.1 Valve rating. .3 4.2 Shell rating. .3 4.3 Seat and seal rating .3 5 Design .4 5.1 Flow passageway ..4 5.2 Body ..5 5.2.1 Body wall thickness .5 5.2.2 Flanged ends .8 5.2.3 Butt-welding ends. ..8 5.2.4 Socket welding ends ..8 5.2.5 Threaded ends ..9 5.2.6 Body openings .9 5.2.7 Anti-static design. .9 5.2.8 Anti-blow-out stem.. ..10 5.2.9 Ball-stem construction ..10: 5.2.10 Ball construction. .10 5.2.11 Operating means. .10 5.2.12 Giands. .11 5.2.13 End flange facing interruptions ..11 5.2.14 Shell joints .12 5.2.15 Packing gland bolting. ..13 6 Materials ..13 6.1 Shell ..13 6.2 Shell material repair. .14 6.3 Trim .14 6.4 Identification plate .14 6.5 Bolting ..14 6.6 Seals.. 6.7 Threaded plugs .14 7 Marking. ..14 7.1 Legibility. ..14 7.2 Body marking .14 7.3 Ring joint marking .15 7.4 Identification plate .15 7.5 Special marking for unidirectional valves ..15 8 Testing and inspection ..16 8.1 Pressure tests. ..16 8.1.1 General ..16 8.1.2 Shell test .16 8.1.3 Closure tightness test. .16 8.2 Inspection... ..17 8.3 Examination. ..17 8.4 Supplementary examination .18 9 Preparation for despatch ..18 iii icensee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 d without license from IHS