EN 61511-2:2004

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 EN 61511-1. This standard has been organized so that each clause and subclause number herein addresses the same clause number in EN 61511-1

Funktionale Sicherheit - Sicherheitstechnische Systeme für die Prozessindustrie - Teil 2: Anleitungen zur Anwendung des Teils 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

provides guidance on the specification, design, installation, operation and maintenance of Safety Instrumented Functions and related safety instrumented system as defined in EN 61511-1. This standard has been organized so that each clause and subclause number herein addresses the same clause number in EN 61511-1

Funkcijska varnost - Sistemi z varnostnimi instrumenti za sektor procesne industrije - 2. del: Smernice za uporabo IEC 61511-1 (IEC 61511-2:2003)

General Information

• Status: Withdrawn
• Publication Date: 22-Dec-2004
• Withdrawal Date: 30-Sep-2007
• ICS: 13.110 - Safety of machinery
• ICS: 25.040.01 - Industrial automation systems in general
• Technical Committee: CLC/TC 65X - Industrial-process measurement, control and automation
• Drafting Committee: IEC/SC 65A - IEC_SC_65A
• Parallel Committee: IEC/SC 65A - IEC_SC_65A
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 21-Apr-2020
• Completion Date: 21-Apr-2020
• Ref Project: SIST EN 61511-2:2007 - Functional safety - Safety instrumented systems for the process industry sector -- Part 2: Guidelines for the application of IEC 61511-1

Relations

• Replaced By: EN 61511-2:2017 - Functional safety - Safety instrumented systems for the process industry sector - Part 2: Guidelines for the application of IEC 61511-1
• Effective Date: 29-Jan-2023

Standards Content (Sample)

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EUROPEAN STANDARD EN 61511-2
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2004

ICS 25.040.01;13.110
English version
Functional safety –
Safety instrumented systems for the process industry sector
Part 2: Guidelines for the application of IEC 61511-1
(IEC 61511-2:2003)
Sécurité fonctionnelle –  Funktionale Sicherheit -
Systèmes instrumentés de sécurité Sicherheitstechnische Systeme
pour le secteur des industries für die Prozessindustrie
de transformation Teil 2: Anleitungen zur Anwendung
Partie 2: Lignes directrices pour des Teils 1
l'application de la CEI 61511-1 (IEC 61511-2:2003)
(CEI 61511-2:2003)
This European Standard was approved by CENELEC on 2004-10-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61511-2:2004 E
Foreword
The text of the International Standard IEC 61511-2:2003, prepared by SC 65A, System aspects, of
IEC TC 65, Industrial-process measurement and control, was submitted to the Unique Acceptance
Procedure and was approved by CENELEC as EN 61511-2 on 2004-10-01 without any modification.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2005-10-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-10-01
__________
Endorsement notice
The text of the International Standard IEC 61511-2:2003 was approved by CENELEC as a European
Standard without any modification.
__________
NORME CEI
INTERNATIONALE IEC
61511-2
INTERNATIONAL
Première édition
STANDARD
First edition
2003-07
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
Functional safety –
Safety instrumented systems
for the process industry sector –
Part 2:
Guidelines for the application
of IEC 61511-1
© IEC 2004 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. 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
CODE PRIX
PRICE CODE XC
Commission Electrotechnique Internationale
International Electrotechnical Commission
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Pour prix, voir catalogue en vigueur
For price, see current catalogue

61511-2 © IEC:2004 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11
1 Scope.17
2 Normative references.17
3 Terms, definitions and abbreviations .17
4 Conformance to this International Standard .17
5 Management of functional safety .19
5.1 Objective.19
5.2 Requirements.19
6 Safety lifecycle requirements.33
6.1 Objective.33
6.2 Requirements.33
7 Verification.35
7.1 Objective.35
8 Process hazard and risk assessment.35
8.1 Objectives.35
8.2 Requirements.35
9 Allocation of safety functions to protection layers .41
9.1 Objective.41
9.2 Requirements of the allocation process .41
9.3 Additional requirements for safety integrity level 4.47
9.4 Requirement on the basic process control system as a layer of protection.47
9.5 Requirements for preventing common cause, common mode and dependent
failures .49
10 SIS safety requirements specification .51
10.1 Objective.51
10.2 General requirements.51
10.3 SIS safety requirements .51
11 SIS design and engineering.55
11.1 Objective.55
11.2 General requirements.55
11.3 Requirements for system behaviour on detection of a fault .65
11.4 Requirements for hardware fault tolerance .65
11.5 Requirements for selection of components and subsystems .67
11.6 Field devices.73
11.7 Interfaces.73
11.8 Maintenance or testing design requirements.79
11.9 SIF probability of failure .81
12 Requirements for application software, including selection criteria for utility
software .85
12.1 Application software safety lifecycle requirements .85
12.2 Application software safety requirements specification .93

61511-2 © IEC:2004 – 5 –
12.3 Application software safety validation planning.97
12.4 Application software design and development .97
12.5 Integration of the application software with the SIS subsystem .113
12.6 FPL and LVL software modification procedures .113
12.7 Application software verification.115
13 Factory acceptance testing (FAT) .117
13.1 Objectives.117
13.2 Recommendations.117
14 SIS installation and commissioning.119
14.1 Objectives.119
14.2 Requirements.119
15 SIS safety validation.119
15.1 Objective.119
15.2 Requirements.119
16 SIS operation and maintenance.121
16.1 Objectives.121
16.2 Requirements.121
16.3 Proof testing and inspection .121
17 SIS modification.125
17.1 Objective.125
17.2 Requirements.125
18 SIS decommissioning.125
18.1 Objectives.125
18.2 Requirements.125
19 Information and documentation requirements .127
19.1 Objectives.127
19.2 Requirements.127
Annex A (informative) Example of techniques for calculating the probability of failure
on demand for a safety instrumented function.129
Annex B (informative) Typical SIS architecture development.131
Annex C (informative) Application features of a safety PLC .141
Annex D (informative) Example of SIS logic solver application software development
methodology .145
Annex E (informative) Example of development of externally configured diagnostics
for a safety-configured PE logic solver.155
Figure 1 – Overall framework of this standard.15
Figure 2 – BPCS function and initiating cause independence illustration.49
Figure 3 – Software development lifecycle (the V-model) .87
Figure C.1 – Logic solver .143
Figure E.1 – EWDT timing diagram .159
Table 1 – Typical Safety Manual organisation and contents .109
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