ISO INTERNATIONAL STANDARD 4126-2 Secondedition 2018-12 Safety devices for protection against excessive pressure - Part 2: Bursting disc safety devices Dispositifs de sécurite pour protection contre les pressions excessives- Partie 2: Dispositifs de surete a disque de rupture Reference number IS0 4126-2:2018(E) so @ IS0 2018 IS0 4126-2:2018(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 2018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2018 - All rights reserved IS0 4126-2:2018(E) Contents Page Foreword ..V Introduction. ...vi 1 Scope. 2 Normative references ...1. 3 Terms and definitions 4 Materials ..4 4.1 Selection of materials .4 4.2 Material specifications 4.3 Protection from corrosion ..5 5 Types of bursting discs. .5 5.1 Conventional domed bursting discs (Forward acting) 5.2 Reverse domed bursting discs (Reverse acting) .6 5.3 Flat bursting discs .. 6 5.4 Other types and designs 、 Bursting disc holders. .8 6 6.1 Design ..8 6.1.1 Pressure-containing capability ..8 6.1.2 Other design requirements. ..8 6.2 Types. ..8 6.3 Connections .10 7 Back pressure supports .11 7.1 General .11 7.2 Opening back pressure supports .11 7.3 Non-opening back pressure supports. .11 8 Temperature shields .11 9 Stiffening rings ..11 10 Gaskets/seals. ..11 11 Assembly of bursting disc safety devices .11 11.1 General. .11 11.2 Bursting disc safety devices with replaceable bursting disc assemblies ..12 11.3 Bursting disc safety devices with non-replaceable bursting disc assemblies ..12 12 Specified bursting pressure requirements ..12 13 Inspection by the manufacturer ..13 14 Test procedures .14 14.1 General. .14 14.2 Pressure testing ..14 14.3 Burst testing. ..14 14.3.1 General. .14 14.3.2 Coincident temperature in the range 15 °C to 30 °C ..14 14.3.3 Coincident temperature above or below the range 15 °C to 30 °C ..14 14.3.4 Procedure for burst testing. .15 14.4 Leak testing. .16 14.4.1 General .16 14.4.2 Selectionofacceptableleakagerate .16 14.5 Non-destructive examination. .16 15 Certification .16 16 Product designation ..17 @ IS0 2018 - All rights reserved iii