IEC 61511-1:2016/AMD1:2017

Amendment 1 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and application programming requirements

Amendement 1 - Sécurité fonctionnelle - Systèmes instrumentés de sécurité pour le secteur des industries de transformation - Partie 1: Cadre, définitions, exigences pour le système, le matériel et la programmation d'application

General Information

• Status: Published
• Publication Date: 15-Aug-2017
• ICS: 13.110 - Safety of machinery
• ICS: 25.040.01 - Industrial automation systems in general
• Technical Committee: SC 65A - System aspects
• Current Stage: PPUB - Publication issued
• Start Date: 16-Aug-2017
• Completion Date: 11-Aug-2017

Relations

• Amends: IEC 61511-1:2016 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and application programming requirements
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61511-1 ®
Edition 2.0 2017-08
INTERNATIONAL
STANDARD
AMENDMENT 1
Functional safety – Safety instrumented systems for the process industry
sector –
Part 1: Framework, definitions, system, hardware and application programming
requirements
IEC 61511-1:2016-02/AMD1:2017-08(en)

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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IEC 61511-1 ®
Edition 2.0 2017-08
INTERNATIONAL
STANDARD
AMENDMENT 1
Functional safety – Safety instrumented systems for the process industry

sector –
Part 1: Framework, definitions, system, hardware and application programming

requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.110; 25.040.01 ISBN 978-2-8322-4582-8

– 2 – IEC 61511-1:2016/AMD1:2017
© IEC 2017
FOREWORD
This amendment has been prepared by subcommittee 65A: System aspects, of IEC technical
committee 65: Industrial-process measurement, control and automation.
The text of this amendment is based on the following documents:
FDIS Report on voting
65A/844/FDIS 65A/848/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website 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.
A bilingual version of this publication may be issued at a later date.

_____________
1 Scope
In Note 4 under Figure 3, replace the words "and IEC 61511-2:2016" by "and A.7.2.2 in
IEC 61511-2:2016".
3 Terms, definitions and abbreviations
3.2.11
dangerous failure
Replace the text of the existing Note 2 to entry with the following:
Note 2 to entry: When fault tolerance is implemented, a dangerous failure can lead to either:
• a degraded SIF where the safety action is available but there is either a higher PFD or a PFH, or
• a disabled SIF where the safety action is completely disabled or the hazardous event has been induced.
3.2.15.1
Replace the e
...

IEC 61511-1 ®
Edition 2.0 2017-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Functional safety – Safety instrumented systems for the process industry
sector –
Part 1: Framework, definitions, system, hardware and application programming
requirements
Sécurite fonctionnelle – Systèmes instrumentes de sécurité pour le secteur des
industries de transformation –
Partie 1: Cadre, définitions, exigences pour le système, le matériel et la
programmation d'application
IEC 61511-1:2016-02/AMD1:2017-08(en-fr)

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
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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.

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3, rue de Varembé [e-mail]
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.

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variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
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If you wish to give us your feedback on this publication or TC 37, 77, 86 and CISPR.

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IEC 61511-1 ®
Edition 2.0 2017-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Functional safety – Safety instrumented systems for the process industry

sector –
Part 1: Framework, definitions, system, hardware and application programming

requirements
Sécurite fonctionnelle – Systèmes instrumentes de sécurité pour le secteur des

industries de transformation –

Partie 1: Cadre, définitions, exigences pour le système, le matériel et la

programmation d'application
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.110; 25.040.01 ISBN 978-2-8322-7951-9

– 2 – IEC 61511-1:2016/AMD1:2017
© IEC 2017
FOREWORD
This amendment has been prepared by subcommittee 65A: System aspects, of IEC technical
committee 65: Industrial-process measurement, control and automation.
This bilingual version (2020-03) corresponds to the monolingual English version, published in
2017-08.
The text of this amendment is based on the following documents:
FDIS Report on voting
65A/844/FDIS 65A/848/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The French version of this standard has not been voted upon.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website 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.
_____________
1 Scope
In Note 4 under Figure 3, replace the words "and IEC 61511-2:2016" by "and A.7.2.2 in
IEC 61511-2:2016".
3 Terms, definitions and abbreviations
3.2.11
dangerous failure
Replace the text of the existing Note 2 to entry with the following:
Note 2 to entry: When fault tolerance is implemented, a dangerous failure can lead to either:
• a degraded SIF where the safety action is available but there is either a higher PFD or a PFH, or
• a disabled SIF where the safety action is completely disabled or the hazardous event has been induced.
3.2.15.1
Replace the existing entry with the following:

© IEC 2017
3.2.15.1
diagnostic coverage
DC
fraction of dangerous failures rates detected by diagnostics. Diagnostic coverage does not
include any faults detected by proof tests
Note 1 to entry: Diagnostic coverage is typically applied to SIS devices or SIS subsystems. E.g., the diagnostic
coverage is typically determined for a sensor, final element or a logic solver.
Note 2 to entry: For safety applications the diagnostic coverage is typically applied to dangerous failures of SIS
devices or SIS subsystems. For example, the diagnostic coverage for the dangerous failures of a device is
DC = λ /λ , where λ is the dangerous detected failure rate and λDT is the total dangerous failure rate. For
DD DT DD
a SIS subsystem with internal redundancy, DC is time dependant: DC(t) = λ (t) / λ (t).
DD DT
Note 3 to entry: When the diagnostic coverage (DC) and the total dangerous failure rate (λ ) are given, the
DT
detected (λ ) and undetected dangerous failures (λ ) can be computed as follows:
DD DU
λ = DC × λ and λ = (1-DC) × λ .
DD DT DU DT
3.2.18
failure
Replace, in Note 4 to entry, the words "(see 3.2.61 and 3.2.83)" with “(see 3.2.59 and
3.2.81)".
3.2.26
hardware safety integrity
Delete, in Note 1 to entry, the words "(continuous mode of operation)" and “(demand mode of
operation)”.
3.2.62
safe failure
Delete, in the first dash of Note 2 to entry the words "(demand mode of operation)" and
“(continuous mode of operation)”.
3.2.69
safety integrity level
SIL
Replace the existing Note 1 to entry with the following:
Note 1 to entry: The higher the SIL, the lower the expected PFDavg or the lower the average frequency of a
dangerous failure causing a hazardous event.
8 Process H&RA
8.1 Objectives
Replace, in 8.1, the existing Note 3 with the following:
NOTE 3 The risk reduction can be accomplished using several layers of protection (see Clause 9).
9 Allocation of safety functions to protection layers
Add, in Note 3 of 9.2.4, the words "or demand" between "continuous" and "mode" (twice).
10.3 SIS safety requirements
Replace the existing text of 10.3.1 with the following:

– 4 – IEC 61511-1:2016/AMD1:2017
© IEC 2017
10.3.1 The obje
...