IEC_TR_61511-4-2020.pdf

IEC TR 61511-4 Edition 1.0 2020-02 TECHNICAL REPORT Functional safety Safety instrumented systems for the process industry sector Part 4:Explanation and rationale for changes in IEC 61511-1 from Edition 1 to Edition 2 IEC TR 61511-4:2020-02(en)THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2020 IEC,Geneva,Switzerland 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 IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.IEC Central Office Tel.:+41 22 919 02 11 3,rue de Varemb infoiec.ch CH-1211 Geneva 20 www.iec.ch Switzerland About the IEC The International Electrotechnical Commission(IEC)is the leading global organization that prepares and publishes International Standards for all electrical,electronic and related technologies.About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigendum or an amendment might have been published.IEC publications search-webstore.iec.ch/advsearchform The advanced search enables to find IEC publications by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,replaced and withdrawn publications.IEC Just Published-webstore.iec.ch/justpublished Stay up to date on all new IEC publications.Just Published details all new publications released.Available online and once a month by email.IEC Customer Service Centre-webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further assistance,please contact the Customer Service Centre:salesiec.ch.Electropedia-www.electropedia.org The worlds leading online dictionary on electrotechnology,containing more than 22 000 terminological entries in English and French,with equivalent terms in 16 additional languages.Also known as the International Electrotechnical Vocabulary(IEV)online.IEC Glossary-std.iec.ch/glossary 67 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002.Some entries have been collected from earlier publications of IEC TC 37,77,86 and CISPR.IEC TR 61511-4 Edition 1.0 2020-02 TECHNICAL REPORT Functional safety Safety instrumented systems for the process industry sector Part 4:Explanation and rationale for changes in IEC 61511-1 from Edition 1 to Edition 2 INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 13.110,ICS 25.040.01 ISBN 978-2-8322-7870-3 Registered trademark of the International Electrotechnical Commission Warning!Make sure that you obtained this publication from an authorized distributor.2 IEC TR 61511-4:2020 IEC 2020 CONTENTS CONTENTS.2 FOREWORD.5 INTRODUCTION.7 1 Scope.8 2 Normative references.8 3 Terms,definitions and abbreviated terms.8 3.1 Terms and definitions.8 3.2 Abbreviated terms.9 4 Background.10 5 Management of functional safety(IEC 61511-1 Ed.2 Clause 5).10 5.1 Why is this clause important?.10 5.2 Common misconceptions.10 5.3 What was changed from Ed.1 to Ed.2 and why?.11 5.3.1 Existing systems.11 5.3.2 Change management.11 5.3.3 Performance metrics and quality assurance.11 5.3.4 Competency.12 5.3.5 More requirements for functional safety product and service providers.12 5.4 Summary on how.12 6 Safety life cycle(IEC 61511-1 Ed.2 Clause 6).12 6.1 Why is this clause important?.12 6.2 Common misconceptions.12 6.3 What was changed from Ed.1 to Ed.2 and why?.13 6.4 Summary on how.13 7 Verification(IEC 61511-1 Ed.2 Clause 7).13 7.1 Why is this clause important?.13 7.2 Common misconceptions.13 7.3 What was changed from Ed.1 to Ed.2 and why?.13 7.4 Summary on how.13 8 Hazard and risk analysis(IEC 61511-1 Ed.2 Clause 8).13 8.1 Why is this clause important?.13 8.2 Common misconceptions.14 8.3 What was changed from Ed.1 to Ed.2 and why?.14 8.4 Summary on how.15 9 Allocation of safety functions to protection layers (IEC 61511-1 Ed.2 Clause 9).15 9.1 Why is this clause important?.15 9.2 Common misconceptions.15 9.3 What was changed from Ed.1 to Ed.2 and why?.16 9.3.1 Limits on BPCS protection layers.16 9.3.2 Requirements for claiming RRF 10 000 in total for instrumented safeguards.16 9.4 Summary on how.16 10 SIS safety requirements specification(IEC 61511-1 Ed.2 Clause 10).17 10.1 Why is this clause important?.17 10.2 Common misconceptions.17 10.3 What was changed from Ed.1 to Ed.2 and why?.18 IEC TR 61511-4:2020 IEC 2020 3 10.4 Summary on how.18 11 Design and engineering(IEC 61511-1 Ed.2 Clause 11).18 11.1 Why is this clause important?.18 11.2 Common misconceptions.18 11.3 What was changed from Ed.1 to Ed.2 and why?.19 11.3.1