Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 1: General requirements (see <a href="http://www.iec.ch/functionalsafety">Functional Safety and IEC 61508</a>)

IEC 61508-1:2010 covers those aspects to be considered when electrical/electronic/programmable electronic (E/E/PE) systems are used to carry out safety functions. A major objective of this standard is to facilitate the development of product and application sector international standards by the technical committees responsible for the product or application sector. This will allow all the relevant factors, associated with the product or application, to be fully taken into account and thereby meet the specific needs of users of the product and the application sector. A second objective of this standard is to enable the development of E/E/PE safety-related systems where product or application sector international standards do not exist. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages. It has the status of a basic safety publication according to IEC Guide 104.
NEW! Also available:  IEC Standards+ 61508:2010, containing all parts, together with a commented Redline version. Changes made in this 2nd edition are highlighted and commented by a leading world expert.
This publication is of high relevance for Smart Grid.

Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques programmables relatifs à la sécurité - Partie 1: Exigences générales

La CEI 61508-1:2010 traite des aspects à prendre en considération lors de l'utilisation de systèmes électriques/électroniques/électroniques programmables (E/E/PE) pour exécuter des fonctions de sécurité. L'un des objectifs majeurs de la présente norme est de permettre l'élaboration par les comités d'études qui en sont responsables de normes internationales de produit et d'application sectorielle. Cela permet de prendre pleinement en compte l'ensemble des facteurs pertinents associés au produit ou à l'application, et donc de répondre aux besoins spécifiques des utilisateurs du produit et du secteur d'application concernés. Un second objectif de la présente norme est de permettre le développement de systèmes E/E/PE relatifs à la sécurité en l'absence de normes internationales de produit ou d'application sectorielle. Cette deuxième édition annule et remplace la première édition publiée en 1998 dont elle constitue une révision technique. Elle a fait l'objet d'une révision approfondie et intègre de nombreux commentaires reçus lors des différentes phases de révision. Elle a le statut d'une publication fondamentale de sécurité conformément au Guide CEI 104.

General Information

Status
Published
Publication Date
29-Apr-2010
Technical Committee
Current Stage
PPUB - Publication issued
Start Date
30-Apr-2010
Completion Date
30-Apr-2010
Ref Project

Buy Standard

Standard
IEC 61508-1:2010 - Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 1: General requirements (see <a href="http://www.iec.ch/functionalsafety">Functional Safety and IEC 61508</a>)
English and French language
127 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC 61508-1
Edition 2.0 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ

Functional safety of electrical/electronic/programmable electronic safety-related

systems –
Part 1: General requirements
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité –
Partie 1: Exigences générales
IEC 61508-1:2010
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2010 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

IEC's 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.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite

ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub

The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).

It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub

Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available

on-line and also by email.
ƒ Electropedia: www.electropedia.org

The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions

in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical

Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv

If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service

Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
A propos de la CEI

La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des

normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI

Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez

l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm

Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,

texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.

ƒ Just Published CEI: www.iec.ch/online_news/justpub

Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles

publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org

Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et

définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé

Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm

Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du

Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
---------------------- Page: 2 ----------------------
IEC 61508-1
Edition 2.0 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ

Functional safety of electrical/electronic/programmable electronic safety-related

systems –
Part 1: General requirements
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité –
Partie 1: Exigences générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX
ICS 13.110; 25.040; 29.020 ISBN 978-2-88910-524-3
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – 61508-1 © IEC:2010
CONTENTS

FOREWORD...........................................................................................................................5

INTRODUCTION.....................................................................................................................7

1 Scope...............................................................................................................................9

2 Normative references......................................................................................................12

3 Definitions and abbreviations ..........................................................................................12

4 Conformance to this standard .........................................................................................12

5 Documentation ...............................................................................................................13

5.1 Objectives .............................................................................................................13

5.2 Requirements ........................................................................................................13

6 Management of functional safety.....................................................................................14

6.1 Objectives .............................................................................................................14

6.2 Requirements ........................................................................................................14

7 Overall safety lifecycle requirements ...............................................................................17

7.1 General .................................................................................................................17

7.1.1 Introduction ...............................................................................................17

7.1.2 Objectives and requirements – general ......................................................20

7.1.3 Objectives .................................................................................................25

7.1.4 Requirements ............................................................................................25

7.2 Concept.................................................................................................................25

7.2.1 Objective ...................................................................................................25

7.2.2 Requirements ............................................................................................26

7.3 Overall scope definition .........................................................................................26

7.3.1 Objectives .................................................................................................26

7.3.2 Requirements ............................................................................................26

7.4 Hazard and risk analysis ........................................................................................27

7.4.1 Objectives .................................................................................................27

7.4.2 Requirements ............................................................................................27

7.5 Overall safety requirements ...................................................................................28

7.5.1 Objective ...................................................................................................29

7.5.2 Requirements ............................................................................................29

7.6 Overall safety requirements allocation....................................................................30

7.6.1 Objectives .................................................................................................30

7.6.2 Requirements ............................................................................................31

7.7 Overall operation and maintenance planning ..........................................................35

7.7.1 Objective ...................................................................................................35

7.7.2 Requirements ............................................................................................35

7.8 Overall safety validation planning...........................................................................37

7.8.1 Objective ...................................................................................................37

7.8.2 Requirements ............................................................................................37

7.9 Overall installation and commissioning planning.....................................................38

7.9.1 Objectives .................................................................................................38

7.9.2 Requirements ............................................................................................38

7.10 E/E/PE system safety requirements specification ...................................................38

7.10.1 Objective ...................................................................................................39

7.10.2 Requirements ............................................................................................39

7.11 E/E/PE safety-related systems – realisation ...........................................................41

---------------------- Page: 4 ----------------------
61508-1 © IEC:2010 – 3 –

7.11.1 Objective ...................................................................................................41

7.11.2 Requirements ............................................................................................41

7.12 Other risk reduction measures – specification and realisation.................................41

7.12.1 Objective ...................................................................................................41

7.12.2 Requirements ............................................................................................41

7.13 Overall installation and commissioning...................................................................41

7.13.1 Objectives .................................................................................................41

7.13.2 Requirements ............................................................................................42

7.14 Overall safety validation.........................................................................................42

7.14.1 Objective ...................................................................................................42

7.14.2 Requirements ............................................................................................42

7.15 Overall operation, maintenance and repair .............................................................43

7.15.1 Objective ...................................................................................................43

7.15.2 Requirements ............................................................................................43

7.16 Overall modification and retrofit .............................................................................46

7.16.1 Objective ...................................................................................................46

7.16.2 Requirements ............................................................................................47

7.17 Decommissioning or disposal.................................................................................48

7.17.1 Objective ...................................................................................................48

7.17.2 Requirements ............................................................................................48

7.18 Verification ............................................................................................................49

7.18.1 Objective ...................................................................................................49

7.18.2 Requirements ............................................................................................49

8 Functional safety assessment .........................................................................................50

8.1 Objective ...............................................................................................................50

8.2 Requirements ........................................................................................................50

Annex A (informative) Example of a documentation structure................................................54

Bibliography ..........................................................................................................................60

Figure 1 – Overall framework of the IEC 61508 series ...........................................................11

Figure 2 – Overall safety lifecycle ..........................................................................................18

Figure 3 – E/E/PE system safety lifecycle (in realisation phase) .............................................19

Figure 4 – Software safety lifecycle (in realisation phase) ......................................................19

Figure 5 – Relationship of overall safety lifecycle to the E/E/PE system and software

safety lifecycles.....................................................................................................................20

Figure 6 – Allocation of overall safety requirements to E/E/PE safety-related systems

and other risk reduction measures.........................................................................................32

Figure 7 – Example of operations and maintenance activities model ......................................45

Figure 8 – Example of operation and maintenance management model .................................46

Figure 9 – Example of modification procedure model.............................................................48

Figure A.1 – Structuring information into document sets for user groups ................................59

Table 1 – Overall safety lifecycle – overview..........................................................................21

Table 2 – Safety integrity levels – target failure measures for a safety function operating

in low demand mode of operation ..........................................................................................33

Table 3 – Safety integrity levels – target failure measures for a safety function operating

in high demand mode of operation or continuous mode of operation ......................................34

---------------------- Page: 5 ----------------------
– 4 – 61508-1 © IEC:2010
Table 4 – Minimum levels of independence of those carrying out functional safety

assessment (overall safety lifecycle phases 1 to 8 and 12 to 16 inclusive (see Figure 2)) .......53

Table 5 – Minimum levels of independence of those carrying out functional safety

assessment (overall safety lifecycle phases 9 and 10, including all phases of E/E/PE

system and software safety lifecycles (see Figures 2, 3 and 4)) .............................................53

Table A.1 – Example of a documentation structure for information related to the overall

safety lifecycle ......................................................................................................................56

Table A.2 – Example of a documentation structure for information related to the E/E/PE

system safety lifecycle...........................................................................................................57

Table A.3 – Example of a documentation structure for information related to the

software safety lifecycle ........................................................................................................58

---------------------- Page: 6 ----------------------
61508-1 © IEC:2010 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/
PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS –
Part 1: General requirements
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61508-1 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 revision.

This edition has been subject to a thorough review and incorporates many comments received

at the various revision stages.
It has the status of a basic safety publication according to IEC Guide 104.
---------------------- Page: 7 ----------------------
– 6 – 61508-1 © IEC:2010
The text of this standard is based on the following documents:
FDIS Report on voting
65A/548/FDIS 65A/572/RVD

Full information on the voting for the 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 / electronic / 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

maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 8 ----------------------
61508-1 © IEC:2010 – 7 –
INTRODUCTION

Systems comprised of electrical and/or electronic elements have been used for many years to

perform safety functions in most application sectors. Computer-based 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 responsible 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)

elements 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 international 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 technologies

(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 making 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 great 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 International 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, through design, implementation, operation and maintenance

to decommissioning) when E/E/PE systems are used to perform safety functions;

– has been conceived with a rapidly developing technology in mind; the framework is

sufficiently robust and comprehensive to cater for future developments;

– enables product and application sector international standards, dealing with E/E/PE safety-

related systems, to be developed; the development of product and application sector

international standards, within the framework of this standard, should lead to a high level of

consistency (for example, of underlying principles, terminology etc.) both within application

sectors and across application sectors; this will have both safety and economic benefits;

– provides a method for the development of the safety requirements specification necessary

to achieve the required functional safety for E/E/PE safety-related systems;
– adopts a risk-based approach by which the safety integrity requirements can be
determined;

– introduces safety integrity levels for specifying the target level of safety integrity for the

safety functions to be implemented by the E/E/PE safety-related systems;

NOTE 2 The standard does not specify the safety integrity level requirements for any safety function, nor does it

mandate how the safety integrity level is determined. Instead it provides a risk-based conceptual framework and

example techniques.
---------------------- Page: 9 ----------------------
– 8 – 61508-1 © IEC:2010

– sets target failure measures for safety functions carried out by E/E/PE safety-related

systems, which are linked to the safety integrity levels;

– sets a lower limit on the target failure measures for a safety function carried out by a single

E/E/PE safety-related system. For E/E/PE safety-related systems operating in

– a low demand mode of operation, the lower limit is set at an average probability of a

dangerous failure on demand of 10 ;

– a high demand or a continuous mode of operation, the lower limit is set at an average

–9 -1
frequency of a dangerous failure of 10 [h ];

NOTE 3 A single E/E/PE safety-related system does not necessarily mean a single-channel architecture.

NOTE 4 It may be possible to achieve designs of safety-related systems with lower values for the target safety

integrity for non-complex systems, but these limits are considered to represent what can be achieved for relatively

complex systems (for example programmable electronic safety-related systems) at the present time.

– sets requirements for the avoidance and control of systematic faults, which are based on

experience and judgement from practical experience gained in industry. Even though the

probability of occurrence of systematic failures cannot in general be quantified the standard

does, however, allow a claim to be made, for a specified safety function, that the target

failure measure associated with the safety function can be considered to be achieved if all

the requirements in the standard have been met;

– introduces systematic capability which applies to an element with respect to its confidence

that the systematic safety integrity meets the requirements of the specified safety integrity

level;

– adopts a broad range of principles, techniques and measures to achieve functional safety

for E/E/PE safety-related systems, but does not explicitly use the concept of fail safe.

However, the concepts of “fail safe” and “inherently safe” principles may be applicable and

adoption of such concepts is acceptable providing the requirements of the relevant clauses

in the standard are met.
---------------------- Page: 10 ----------------------
61508-1 © IEC:2010 – 9 –
FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/
PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS –
Part 1: General requirements
1 Scope
1.1 This International Standard covers those aspects to be considered when

electrical/electronic/programmable electronic (E/E/PE) systems are used to carry out safety

functions. A major objective of this standard is to facilitate the development of product and

application sector international standards by the technical committees responsible for the

product or application sector. This will allow all the relevant factors, associated with the product

or application, to be fully taken into account and thereby meet the specific needs of users

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.