ISO INTERNATIONAL STANDARD 21013-4 First edition 2012-06-01 Cryogenic vessels Pilot operated pressure-relief devices Part 4: Pressure-relief accessories for cryogenic service Récipients cryogeniques -Dispositifs de sécurité pour le service cryogénique- Partie 4: Dispositifs de sécurite pour la pression a pilotage automatique Reference number ISO 21013-4:2012(E) LSO @ ISO 2012 HS under ted without license from IHS Not for Resale ISO21013-4:2012(E) COPYRIGHTPROTECTEDDOCUMENT ISO2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 · CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland @ ISO 2012 -All rights reserved No reproduction networking permitted without license from IHS Not for Resale ISO 21013-4:2012(E) Contents Page Foreword ..iv 1 Scope 2 Normative reference : Terms and definitions 4 Requirements 3 4.1 General 4.2 Design. 3 4.3 Materials 5 Qualification and testing 5.1 Type approval.. 5 5.2 Type approval tests. 5.3 Production testing. 8 6 Determination of the certified coefficient of discharge (Kdr) 8 7 Setpressuretolerances 8 8 Re-seating pressure 8 6 Cleanliness 8 10 Marking.... 8 10.1 Marking on the shell body of the main valve 8 10.2 Marking on the body of the pilot valve. 8 10.3 Marking on an identification plate 9 10.4 Additional marking.. 9 11 Sealing. Bibliography 10 ili se with I ut license from IHS Not for Resale