IEC_61511-2.pdf

INTERNATIONALSTANDARDIEC61511-2First edition2003-07Functional safety Safety instrumented systemsfor the process industry sector Part 2:Guidelines for the application of IEC 61511-1Reference numberIEC 61511-2:2003(E)COPYRIGHT 2003;International Electrotechnical Commission Document provided by IHS Licensee=Agip KOC/5950653001,User=,09/30/200305:06:03 MDT Questions or comments about this message:please call the DocumentPolicy Group at 1-800-451-1584.-,-,-Publication numbering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series.For example,IEC 34-1 is now referred to as IEC 60034-1.Consolidated editions The IEC is now publishing consolidated versions of its publications.For example,edition numbers 1.0,1.1 and 1.2 refer,respectively,to the base publication,the base publication incorporating amendment 1 and the base publication incorporating amendments 1 and 2.Further information on IEC publications The technical content of IEC publications is kept under constant review by the IEC,thus ensuring that the content reflects current technology.Information relating to this publication,including its validity,is available in the IEC Catalogue of publications(see below)in addition to new editions,amendments and corrigenda.Information on the subjects under consideration and work in progress undertaken by the technical committee which has prepared this publication,as well as the list of publications issued,is also available from the following:IEC Web Site(www.iec.ch)Catalogue of IEC publications The on-line catalogue on the IEC web site(www.iec.ch/searchpub)enables you to search by a variety of criteria including text searches,technical committees and date of publication.On-line information is also available on recently issued publications,withdrawn and replaced publications,as well as corrigenda.IEC Just Published This summary of recently issued publications(www.iec.ch/online_news/justpub)is also available by email.Please contact the Customer Service Centre(see below)for further information.Customer Service Centre If you have any questions regarding this publication or need further assistance,please contact the Customer Service Centre:Email:custserviec.ch Tel:+41 22 919 02 11 Fax:+41 22 919 03 00 COPYRIGHT 2003;International Electrotechnical Commission Document provided by IHS Licensee=Agip KOC/5950653001,User=,09/30/200305:06:03 MDT Questions or comments about this message:please call the DocumentPolicy Group at 1-800-451-1584.-,-,-INTERNATIONALSTANDARDIEC61511-2First edition2003-07Functional safety Safety instrumented systemsfor the process industry sector Part 2:Guidelines for the application of IEC 61511-1 IEC 2003 Copyright-all rights reservedNo part of this publication may be reproduced or utilized in any form or by any means,electronic ormechanical,including photocopying and microfilm,without permission in writing from the publisher.International Electrotechnical Commission,3,rue de Varemb,PO Box 131,CH-1211 Geneva 20,SwitzerlandTelephone:+41 22 919 02 11 Telefax:+41 22 919 03 00 E-mail:inmailiec.ch Web:www.iec.chXBFor price,see current cataloguePRICE CODECommission Electrotechnique InternationaleInternational Electrotechnical Commission COPYRIGHT 2003;International Electrotechnical Commission Document provided by IHS Licensee=Agip KOC/5950653001,User=,09/30/200305:06:03 MDT Questions or comments about this message:please call the DocumentPolicy Group at 1-800-451-1584.-,-,-2 61511-2 IEC:2003(E)CONTENTSFOREWORD.4INTRODUCTION.61Scope.82Normative references.83Terms,definitions and abbreviations.84Conformance to this International Standard.85Management of functional safety.95.1Objective.95.2Requirements.96Safety lifecycle requirements.156.1Objective.156.2Requirements.157Verification.157.1Objective.158Process hazard and risk assessment.168.1Objectives.168.2Requirements.169Allocation of safety functions to protection layers.199.1Objective.199.2Requirements of the allocation process.199.3Additional requirements for safety integrity level 4.219.4Requirement on the basic process control system as a layer of protection.219.5Requirements for preventing common cause,common mode and dependentfailures.2210SIS safety requirements specification.2310.1 Objective.2310.2 General requirements.2310.3 SIS safety requirements.2311SIS design and engineering.2411.1 Objective.2411.2 General requirements.2411.3 Requirements for system behaviour on detection of a fault.2811.4 Requirements for hardware fault tolerance.2811.5 Requirements for selection of components and subsystems.3011.6 Field devices.3211.7 Interfaces.3211.8 Maintenance or testing design requirements.3411.9 SIF probability of failure.3512Requirements for application software,including selection criteria for utilitysoftware.3712.1 Application software safety lifecycle requirements.3712.2 Application software safety requirements specification.4012.3 Application software safety validation planning.4212.4 Application software design and de