IEC 61508-4:2010
(Main)Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 4: Definitions and abbreviations (see Functional Safety and IEC 61508)
Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 4: Definitions and abbreviations (see Functional Safety and IEC 61508)
IEC 61508-4:2010 contains the definitions and explanation of terms that are used in parts 1 to 7 of the IEC 61508 series of standards. The definitions are grouped under general headings so that related terms can be understood within the context of each other. However, it should be noted that these headings are not intended to add meaning to the definitions. 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 4: Définitions et abréviations
La CEI 61508-4:2010 contient les définitions et explications des termes utilisés dans les parties 1 à 7 de la série de normes CEI 61508. Les définitions sont regroupées sous des titres généraux de telle sorte que les termes qui sont en rapport puissent être compris dans le contexte des autres. Toutefois, il convient de remarquer que ces titres ne sont pas attribués pour ajouter un sens aux définitions. 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.
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IEC 61508-4 ®
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 4: Definitions and abbreviations
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité –
Partie 4: Définitions et abréviations
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IEC 61508-4 ®
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 4: Definitions and abbreviations
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité –
Partie 4: Définitions et abréviations
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 25.040.40; 29.020 ISBN 978-2-88910-527-4
– 2 – 61508-4 © IEC:2010
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.7
2 Normative references.9
3 Definitions and abbreviations .9
3.1 Safety terms .10
3.2 Equipment and devices.12
3.3 Systems – general aspects .15
3.4 Systems – safety-related aspects.17
3.5 Safety functions and safety integrity.19
3.6 Fault, failure and error (see Figure 4).22
3.7 Lifecycle activities.27
3.8 Confirmation of safety measures.28
Bibliography .32
Index .33
Figure 1 – Overall framework of the IEC 61508 series .8
Figure 2 – Programmable electronic system .16
Figure 3 – Electrical/electronic/programmable electronic system (E/E/PE system) –
structure and terminology.16
Figure 4 – Failure model .23
Table 1 – Abbreviations used in this standard.9
61508-4 © IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/
PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS –
Part 4: Definitions and abbreviations
FOREWORD
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International Standard IEC 61508-4 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.
– 4 – 61508-4 © IEC:2010
The text of this standard is based on the following documents:
FDIS Report on voting
65A/551/FDIS 65A/575/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
stability 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.
61508-4 © 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-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 ele
...
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