1、 IEC 61508-5 Edition 2.0 2010-04 INTERNATIONAL STANDARD NORME INTERNATIONALE Functional safety of electrical/electronic/programmable electronic safety-related systems Part 5: Examples of methods for the determination of safety integrity levels Scurit fonctionnelle des systmes lectriques/lectroniques
2、/lectroniques programmables relatifs la scurit Partie 5: Exemples de mthodes pour la dtermination des niveaux dintgrit de scurit IEC 61508-5:2010 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2010 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publicati
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17、ONALE Functional safety of electrical/electronic/programmable electronic safety-related systems Part 5: Examples of methods for the determination of safety integrity levels Scurit fonctionnelle des systmes lectriques/lectroniques/lectroniques programmables relatifs la scurit Partie 5: Exemples de mt
18、hodes pour la dtermination des niveaux dintgrit de scurit INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE X ICS 25.040.40 PRICE CODE CODE PRIX ISBN 978-2-88910-528-1 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commissi
19、on Electrotechnique Internationale 2 61508-5 IEC:2010 CONTENTS FOREWORD.3 INTRODUCTION.5 1 Scope.7 2 Normative references .9 3 Definitions and abbreviations9 Annex A (informative) Risk and safety integrity General concepts.10 Annex B (informative) Selection of methods for determining safety integrit
20、y level requirements.21 Annex C (informative) ALARP and tolerable risk concepts .24 Annex D (informative) Determination of safety integrity levels A quantitative method 27 Annex E (informative) Determination of safety integrity levels Risk graph methods .30 Annex F (informative) Semi-quantitative me
21、thod using layer of protection analysis (LOPA) .38 Annex G (informative) Determination of safety integrity levels A qualitative method hazardous event severity matrix44 Bibliography46 Figure 1 Overall framework of the IEC 61508 series 8 Figure A.1 Risk reduction general concepts (low demand mode of
22、operation) .14 Figure A.2 Risk and safety integrity concept 14 Figure A.3 Risk diagram for high demand applications.15 Figure A.4 Risk diagram for continuous mode operation 16 Figure A.5 Illustration of common cause failures (CCFs) of elements in the EUC control system and elements in the E/E/PE saf
23、ety-related system.17 Figure A.6 Common cause between two E/E/PE safety-related systems 18 Figure A.7 Allocation of safety requirements to the E/E/PE safety-related systems, and other risk reduction measures 20 Figure C.1 Tolerable risk and ALARP.25 Figure D.1 Safety integrity allocation example for
24、 safety-related protection system.29 Figure E.1 Risk Graph: general scheme.33 Figure E.2 Risk graph example (illustrates general principles only).34 Figure G.1 Hazardous event severity matrix example (illustrates general principles only) .45 Table C.1 Example of risk classification of accidents .26
25、Table C.2 Interpretation of risk classes 26 Table E.1 Example of data relating to risk graph (Figure E.2).35 Table E.2 Example of calibration of the general purpose risk graph .36 Table F.1 LOPA report.40 61508-5 IEC:2010 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FUNCTIONAL SAFETY OF ELECTRICAL/
26、ELECTRONIC/ PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS Part 5: Examples of methods for the determination of safety integrity levels FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees
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37、 rights. International Standard IEC 61508-5 has been prepared by subcommittee 65A: System aspects, of IEC technical committee 65: Industrial-process measurement, control and automation. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical
38、 revision. This edition has been subject to a thorough review and incorporates many comments received at the various revision stages. 4 61508-5 IEC:2010 The text of this standard is based on the following documents: FDIS Report on voting 65A/552/FDIS 65A/576/RVD Full information on the voting for th
39、e approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2 A list of all parts of the IEC 61508 series, published under the general title Functional safety of electrical / electron
40、ic / programmable electronic safety-related systems, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publica
41、tion. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. 61508-5 IEC:2010 5 INTRODUCTION Systems comprised of electrical and/or electronic elements have been used for many years to perform safety functions in most application sectors. Computer-ba
42、sed systems (generically referred to as programmable electronic systems) are being used in all application sectors to perform non-safety functions and, increasingly, to perform safety functions. If computer system technology is to be effectively and safely exploited, it is essential that those respo
43、nsible for making decisions have sufficient guidance on the safety aspects on which to make these decisions. This International Standard sets out a generic approach for all safety lifecycle activities for systems comprised of electrical and/or electronic and/or programmable electronic (E/E/PE) eleme
44、nts that are used to perform safety functions. This unified approach has been adopted in order that a rational and consistent technical policy be developed for all electrically-based safety-related systems. A major objective is to facilitate the development of product and application sector internat
45、ional standards based on the IEC 61508 series. NOTE 1 Examples of product and application sector international standards based on the IEC 61508 series are given in the Bibliography (see references 1, 2 and 3). In most situations, safety is achieved by a number of systems which rely on many technolog
46、ies (for example mechanical, hydraulic, pneumatic, electrical, electronic, programmable electronic). Any safety strategy must therefore consider not only all the elements within an individual system (for example sensors, controlling devices and actuators) but also all the safety-related systems maki
47、ng up the total combination of safety-related systems. Therefore, while this International Standard is concerned with E/E/PE safety-related systems, it may also provide a framework within which safety-related systems based on other technologies may be considered. It is recognized that there is a gre
48、at variety of applications using E/E/PE safety-related systems in a variety of application sectors and covering a wide range of complexity, hazard and risk potentials. In any particular application, the required safety measures will be dependent on many factors specific to the application. This Inte
49、rnational Standard, by being generic, will enable such measures to be formulated in future product and application sector international standards and in revisions of those that already exist. This International Standard considers all relevant overall, E/E/PE system and software safety lifecycle phases (for example, from initial concept, though design
