IEC 61511-2:2003

Functional safety - Safety instrumented systems for the process industry sector - Part 2: Guidelines for the application of IEC 61511-1

provides guidance on the specification, design, installation, operation and maintenance of Safety Instrumented Functions and related safety instrumented system as defined in IEC 61511-1. This standard has been organized so that each clause and subclause number herein addresses the same clause number in IEC 61511-1 (with the exception of the annexes). It has the status of a horizontal standard in accordance with IEC Guide 108.

Sécurité fonctionnelle - Systèmes instrumentés de sécurité pour le secteur des industries de transformation - Partie 2: Lignes directrices pour l'application de la CEI 61511-1

donne des conseils sur la spécification, la conception, l'installation, l'exploitation et la maintenance des fonctions instrumentées de sécurité et du système instrumenté de sécurité concerné, comme cela est défini par la CEI 61511-1. La présente Partie 2 de la CEI 61511 a été organisée de sorte que chaque numéro d'article mentionné corresponde au même numéro d'article que celui de la CEI 61511-1 (à l'exception des annexes). Elle a le statut d'une norme horizontale conformément au Guide 108 de la CEI.

General Information

• Status: Published
• Publication Date: 03-Jul-2003
• ICS: 13.110 - Safety of machinery
• ICS: 25.040.01 - Industrial automation systems in general
• Technical Committee: SC 65A - System aspects
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 28-Jul-2016

Relations

• Revised: IEC 61511-2:2016 - Functional safety - Safety instrumented systems for the process industry sector - Part 2: Guidelines for the application of IEC 61511-1:2016
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
61511-2
First edition
2003-07
Functional safety –
Safety instrumented systems
for the process industry sector –
Part 2:
Guidelines for the application of IEC 61511-1

Reference number
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.

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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.
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INTERNATIONAL IEC
STANDARD
61511-2
First edition
2003-07
Functional safety –
Safety instrumented systems
for the process industry sector –
Part 2:
Guidelines for the application of IEC 61511-1

 IEC 2003  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
XB
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 61511-2  IEC:2003(E)
CONTENTS
FOREWORD . 4

INTRODUCTION .6

1 Scope . 8

2 Normative references. 8

3 Terms, definitions and abbreviations. 8

4 Conformance to this International Standard . 8

5 Management of functional safety. 9
5.1 Objective . 9
5.2 Requirements . 9
6 Safety lifecycle requirements .15
6.1 Objective .15
6.2 Requirements .15
7 Verification .15
7.1 Objective .15
8 Process hazard and risk assessment .16
8.1 Objectives .16
8.2 Requirements .16
9 Allocation of safety functions to protection layers.19
9.1 Objective .19
9.2 Requirements of the allocation process .19
9.3 Additional requirements for safety integrity level 4 .21
9.4 Requirement on the basic process control system as a layer of protection .21
9.5 Requirements for preventing common cause, common mode and dependent
failures .22
10 SIS safety requirements specification .23
10.1 Objective .23
10.2 General requirements .23
10.3 SIS safety requirements.23
11 SIS design and engineering .24
11.1 Objective .24

11.2 General requirements .24
11.3 Requirements for system behaviour on detection of a fault .28
11.4 Requirements for hardware fault tolerance.28
11.5 Requirements for selection of components and subsystems .30
11.6 Field devices .32
11.7 Interfaces .32
11.8 Maintenance or testing design requirements .34
11.9 SIF probability of failure.35
12 Requirements for application software, including selection criteria for utility
software.37
12.1 Application software safety lifecycle requirements .37
12.2 Application software safety requirements specification.40
12.3 Application software safety validation planning .42
12.4 Application software design and development.42

61511-2  IEC:2003(E) – 3 –
12.5 Integration of the application software with the SIS subsystem .49

12.6 FPL and LVL software modification procedures .49

12.7 Application software verification.50

13 Factory acceptance testing (FAT) .51

13.1 Objectives .51

13.2 Recommendations .51

14 SIS installation and commissioning.52

14.1 Objectives .52

14.2 Requirements .52

15 SIS safety validation .52
15.1 Objective .52
15.2 Requirements .52
16 SIS operation and maintenance .53
16.1 Objectives .53
16.2 Requirements .53
16.3 Proof testing and inspection.53
17 SIS modification.55
17.1 Objective .55
17.2 Requirements .55
18 SIS decommissioning.55
18.1 Objectives .55
18.2 Requirements .55
19 Information and documentation requirements.55
19.1 Objectives .55
19.2 Requirements .55
Annex A (informative) Example of techniques for calculating the probability of failure
on demand for a safety instrumented function .57
Annex B (informative) Typical SIS architecture development.58
Annex C (informative) Application features of a safety PLC.63
Annex D (informative) Example of SIS logic solver application software development
methodology .65
Annex E (informative) Example of development of externally configured diagnostics
for a safety-configured PE logic solver .69

Figure 1 – Overall framework of this standard . 7
Figure 2 – BPCS function and initiating cause independence illustration .21
Figure 3 – Software development lifecycle (the V-model) .38
Figure C.1 – Logic solver .64
Figure E.1 – EWDT timing diagram .71
Table 1 – Typical Safety Manual organisation and contents .47

– 4 – 61511-2  IEC:2003(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
FUNCTIONAL SAFETY –
SAFETY INSTRUMENTED SYSTEMS
FOR THE PROCESS INDUSTRY SECTOR –

Part 2: Guidelines for the application of IEC 61511-1

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
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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 effor
...

IEC 61511-2
Edition 1.0 2003-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Functional safety – Safety instrumented systems for the process industry sector –
Part 2: Guidelines for the application of IEC 61511-1

Sécurité fonctionnelle – Systèmes instrumentés de sécurité pour le secteur des
industries de transformation –
Partie 2: Lignes directrices pour l’application de la CEI 61511-1

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IEC 61511-2
Edition 1.0 2003-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Functional safety – Safety instrumented systems for the process industry sector –
Part 2: Guidelines for the application of IEC 61511-1

Sécurité fonctionnelle – Systèmes instrumentés de sécurité pour le secteur des
industries de transformation –
Partie 2: Lignes directrices pour l’application de la CEI 61511-1

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XC
CODE PRIX
ICS 13.110; 25.040.01 ISBN 2-8318-7556-0
– 2 – 61511-2 © IEC:2003
CONTENTS
FOREWORD.7

INTRODUCTION.6

1 Scope.9

2 Normative references.9

3 Terms, definitions and abbreviations .9

4 Conformance to this International Standard .9

5 Management of functional safety .10
5.1 Objective.10
5.2 Requirements.10
6 Safety lifecycle requirements.17
6.1 Objective.17
6.2 Requirements.17
7 Verification.18
7.1 Objective.18
8 Process hazard and risk assessment.18
8.1 Objectives.18
8.2 Requirements.18
9 Allocation of safety functions to protection layers .21
9.1 Objective.21
9.2 Requirements of the allocation process .21
9.3 Additional requirements for safety integrity level 4.24
9.4 Requirement on the basic process control system as a layer of protection.24
9.5 Requirements for preventing common cause, common mode and dependent
failures .25
10 SIS safety requirements specification .26
10.1 Objective.26
10.2 General requirements.26
10.3 SIS safety requirements .26
11 SIS design and engineering.28
11.1 Objective.28

11.2 General requirements.28
11.3 Requirements for system behaviour on detection of a fault .33
11.4 Requirements for hardware fault tolerance .33
11.5 Requirements for selection of components and subsystems .34
11.6 Field devices.37
11.7 Interfaces.37
11.8 Maintenance or testing design requirements.40
11.9 SIF probability of failure .41
12 Requirements for application software, including selection criteria for utility
software .43
12.1 Application software safety lifecycle requirements .43
12.2 Application software safety requirements specification .47

61511-2 © IEC:2003 – 3 –
12.3 Application software safety validation planning.49

12.4 Application software design and development .49

12.5 Integration of the application software with the SIS subsystem .57

12.6 FPL and LVL software modification procedures .57

12.7 Application software verification.58

13 Factory acceptance testing (FAT) .59

13.1 Objectives.59

13.2 Recommendations.59

14 SIS installation and commissioning.60

14.1 Objectives.60
14.2 Requirements.60
15 SIS safety validation.60
15.1 Objective.60
15.2 Requirements.60
16 SIS operation and maintenance.61
16.1 Objectives.61
16.2 Requirements.61
16.3 Proof testing and inspection .61
17 SIS modification.63
17.1 Objective.63
17.2 Requirements.63
18 SIS decommissioning .63
18.1 Objectives.63
18.2 Requirements.63
19 Information and documentation requirements .64
19.1 Objectives.64
19.2 Requirements.64

Annex A (informative) Example of techniques for calculating the probability of failure
on demand for a safety instrumented function.65
Annex B (informative) Typical SIS architecture development.66
Annex C (informative) Application features of a safety PLC .71
Annex D (informative) Example of SIS logic solver application software development
methodology .73

Annex E (informa
...