SIST EN 61511-1:2007

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

Gives requirements for the specification, design, installation, operation and maintenance of a safety instrumented system, so that it can be confidently entrusted to place and/or maintain the process in a safe state. This standard has been developed as a process sector implementation of IEC 61508. Experts in IEC Subcommittee 65A (System aspects) explain that this sector specific standard of IEC 61508 addresses the functional safety of safety instrumented systems (SIS) for the process sector. "The purpose is to ensure that the safety integrity of safety instrumented systems is adequate taking into account the associated hazards & risks. It falls under the generic IEC 61508 standard and thus required adjustment to the requirements found in IEC 61508 (generic in content since it covers all sectors) to cover process sector needs." The standard will mainly be used by integrators and operators of chemical, petro-chemical and gas process plants. It also has applications in non-nuclear power generation. It will also be used as a benchmark by those responsible for assessing the adequacy of such plants including certification bodies and regulators. IEC 61511-2 Ed. 1.0: Functional safety instrumented systems for the process industry;Part 2: Guidelines in the application of Part 1 wil be published shortly and IEC 61511-3 Ed. 1.0: Functional safety: Safety instrumented systems for the process industry sector;Part 3: Guidance for the determination of safety integrity levels is scheduled to appear in June 2003.

Funktionale Sicherheit - Sicherheitstechnische Systeme für die Prozessindustrie -- Teil 1: Allgemeines, Begriffe, Anforderungen an Systeme, Software und Hardware

Sécurité fonctionnelle - Systèmes instrumentés de sécurité pour le secteur des industries de transformation -- Partie 1: Cadre, définitions, exigences pour le système, le matériel et le logiciel

permet de définir des prescriptions relatives aux spécifications, à la conception, à l'installation, à l'exploitation et à l'entretien d'un système instrumenté de sécurité, de telle manière qu'il puisse être mis en oeuvre en toute confiance, et ainsi établir et/ou maintenir les processus dans un état de sécurité convenable. La présente norme a été conçue pour être une mise en  uvre de la norme internationale CEI 61508 "Sécurité fonctionnelle des systèmes électriques/électroniques/ électroniques programmables relatifs à la sécurité" dans le domaine de l'industrie des processus.
Le contenu du corrigendum de novembre 2004 a été pris en considération dans cet exemplaire.
Elle a le statut d'une norme horizontale conformément au Guide 108 de la CEI.

Funkcijska varnost - Sistemi z varnostnimi instrumenti za sektor procesne industrije - 1. del: Okvirno, definicije, sistem, zahteve za strojno in programsko opremo (IEC 61511-1:2003 + popravek 2004)

General Information

• Status: Published
• Publication Date: 31-Dec-2006
• ICS: 25.040.40 - Industrial process measurement and control
• Technical Committee: MOV - Measuring equipment for electromagnetic quantities
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2007
• Due Date: 01-Jan-2007
• Completion Date: 01-Jan-2007
• Ref Project: EN 61511-1:2004 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and software requirements

Relations

• Replaced By: SIST EN 61511-1:2017 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and application programming Requirements (IEC 61511-1:2016 + COR1:2016)
• Effective Date: 28-Jan-2023
• Replaced By: SIST EN 61511-1:2017 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and application programming Requirements (IEC 61511-1:2016 + COR1:2016)
• Effective Date: 22-Apr-2014

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EUROPEAN STANDARD EN 61511-1
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2004

ICS 13.110; 25.040.01


English version


Functional safety –
Safety instrumented systems for the process industry sector
Part 1: Framework, definitions, system,
hardware and software requirements
(IEC 61511-1:2003 + corrigendum 2004)


Sécurité fonctionnelle –  Funktionale Sicherheit -
Systèmes instrumentés de sécurité Sicherheitstechnische Systeme
pour le secteur des industries für die Prozessindustrie
de transformation Teil 1: Allgemeines, Begriffe,
Partie 1: Cadre, définitions, exigences Anforderungen an Systeme,
pour le système, le matériel et le logiciel Software und Hardware
(CEI 61511-1:2003 + corrigendum 2004) (IEC 61511-1:2003 + Corrigendum 2004)




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 61511-1:2004 E

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EN 61511-1:2004 - 2 -
Foreword
The text of the International Standard IEC 61511-1:2003, 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 61511-1 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
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61511-1:2003 + corrigendum November 2004 was
approved by CENELEC as a European Standard without any modification.
__________

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- 3 - EN 61511-1:2004
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60654-1 1993 Industrial-process measurement and EN 60654-1 1993
control equipment - Operating conditions
Part 1: Climatic conditions

IEC 60654-3 1983 Part 3: Mechanical influences EN 60654-3 1997

1) 2)
IEC 61326 - Electrical equipment for measurement, EN 61326 1997
control and laboratory use - EMC
requirements

1) 2)
IEC 61508-2 - Functional safety of EN 61508-2 2001
electrical/electronic/programmable
electronic safety-related systems
Part 2: Requirements for
electrical/electronic/programmable
electronic safety-related systems

- 1) 2)
IEC 61508-3 Part 3: Software requirements EN 61508-3 2001

- 1) 2)
IEC 61511-2 Functional safety - Safety instrumented EN 61511-2 2004
systems for the process industry sector
Part 2: Guidelines for the application of
IEC 61511-1



1)
Undated reference.
2)
Valid edition at date of issue.

---------------------- Page: 4 ----------------------

NORME CEI
INTERNATIONALE
IEC



61511-1
INTERNATIONAL


Première édition
STANDARD

First edition

2003-01


Sécurité fonctionnelle –
Systèmes instrumentés de sécurité pour
le secteur des industries de transformation –
Partie 1:
Cadre, définitions, exigences pour le système,
le matériel et le logiciel

Functional safety –
Safety instrumented systems
for the process industry sector –
Part 1:
Framework, definitions, system,
hardware and software requirements

 IEC 2003 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
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PRICE CODE
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International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

---------------------- Page: 5 ----------------------

61511-1  IEC:2003 – 3 –
CONTENTS
FOREWORD.9
INTRODUCTION.13

1 Scope.19
2 Normative references.31
3 Abbreviations and definitions.31
3.1 Abbreviations.31
3.2 Definitions.33
4 Conformance to this International Standard .65
5 Management of functional safety .65
5.1 Objective.65
5.2 Requirements.65
6 Safety life-cycle requirements.75
6.1 Objective.75
6.2 Requirements.75
7 Verification.81
7.1 Objective.81
8 Process hazard and risk analysis .81
8.1 Objectives.81
8.2 Requirements.83
9 Allocation of safety functions to protection layers .85
9.1 Objective.85
9.2 Requirements of the allocation process .85
9.3 Additional requirements for safety integrity level 4.87
9.4 Requirements on the basic process control system as a protection layer.89
9.5 Requirements for preventing common cause, common mode and dependent
failures .91
10 SIS safety requirements specification .91
10.1 Objective.91
10.2 General requirements.91
10.3 SIS safety requirements .91
11 SIS design and engineering.95
11.1 Objective.95
11.2 General requirements.95
11.3 Requirements for system behaviour on detection of a fault .97
11.4 Requirements for hardware fault tolerance .101
11.5 Requirements for selection of components and subsystems .103
11.6 Field devices.111
11.7 Interfaces.111
11.8 Maintenance or testing design requirements.115
11.9 SIF probability of failure .117

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61511-1  IEC:2003 – 5 –
12 Requirements for application software, including selection criteria for utility software .119
12.1 Application software safety life-cycle requirements.119
12.2 Application software safety requirements specification .131
12.3 Application software safety validation planning.135
12.4 Application software design and development .135
12.5 Integration of the application software with the SIS subsystem .147
12.6 FPL and LVL software modification procedures .149
12.7 Application software verification.149
13 Factory acceptance testing (FAT) .151
13.1 Objectives.151
13.2 Recommendations.153
14 SIS installation and commissioning.155
14.1 Objectives.155
14.2 Requirements.155
15 SIS safety validation.157
15.1 Objective.157
15.2 Requirements.157
16 SIS operation and maintenance.163
16.1 Objectives.163
16.2 Requirements.163
16.3 Proof testing and inspection .167
17 SIS modification.169
17.1 Objective.169
17.2 Requirements.169
18 SIS decommissioning.171
18.1 Objectives.171
18.2 Requirements.171
19 Information and documentation requirements .171
19.1 Objectives.171
19.2 Requirements.173

Annex A (informative) Differences.175

Bibliography.177

Figure 1 – Overall framework of this standard.17
Figure 2 – Relationship between IEC 61511 and IEC 61508 .23
Figure 3 – Relationship between IEC 61511 and IEC 61508 (see 1.2).25
Figure 4 – Relationship between safety instrumented functions and other functions.27
Figure 5 – Relationship between system, hardware, and software of IEC 61511-1 .29
Figure 6 – Programmable electronic system (PES): structure and terminology .49
Figure 7 – Example SIS architecture.55
Figure 8 – SIS safety life-cycle phases and functional safety assessment stages .71
Figure 9 – Typical risk reduction methods found in process plants .89

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61511-1  IEC:2003 – 7 –
Figure 10 – Application software safety life cycle and its relationship to the SIS safety
life cycle .121
Figure 11 – Application software safety life cycle (in realization phase) .125
Figure 12 − Software development life cycle (the V-model) .125
Figure 13 – Relationship between the hardware and software architectures of SIS .131

Table 1 – Abbreviations used in IEC 61511.31
Table 2 – SIS safety life-cycle overview .77
Table 3 – Safety integrity levels: probability of failure on demand .85
Table 4 – Safety integrity levels: frequency of dangerous failures of the SIF .87
Table 5 – Minimum hardware fault tolerance of PE logic solvers .101
Table 6 – Minimum hardware fault tolerance of sensors and final elements and non-PE
logic solvers .103
Table 7 – Application software safety life cycle: overview .127

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61511-1  IEC:2003 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

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

Part 1: Framework, definitions, system,
hardware and software 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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 61511-1 has been prepared by subcommittee 65A: System
aspects, of IEC technical committee 65: Industrial-process measurement and control.
This bilingual version (2003-12) replaces the English version.

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61511-1  IEC:2003 – 11 –
The text of this standard is based on the following documents:
FDIS Report on voting
65A/368/FDIS 65A/372/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 61511 consists of the following parts, under the general title Functional safety: Safety
instrumented systems for the process industry sector (see Figure 1):
Part 1: Framework, definitions, system, hardware and software requirements
Part 2: Guidelines in the application of IEC 61511-1
Part 3: Guidance for the determination of the required safety integrity levels

The committee has decided that the contents of this publication will remain unchanged until
2007. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of November 2004 have been included in this copy.

---------------------- Page: 10 ----------------------

61511-1  IEC:2003 – 13 –
INTRODUCTION
Safety instrumented systems have been used for many years to perform safety instrumented
functions in the process industries. If instrumentation is to be effectively used for safety
instrumented functions, it is essential that this instrumentation achieves certain minimum
standards and performance levels.
This standard addresses the application of safety instrumented systems for the process
industries. It also requires a process hazard and risk assessment to be carried out to enable
the specification for safety instrumented systems to be derived. Other safety systems are only
considered so that their contribution can be taken into account when considering the
performance requirements for the safety instrumented systems. The safety instrumented
system includes all components and subsystems necessary to carry out the safety
instrumented function from sensor(s) to final element(s).
This standard has two concepts which are fundamental to its application; safety lifecycle and
safety integrity levels.
This standard addresses safety instrumented systems which are based on the use of
electrical/electronic/programmable electronic technology. Where other technologies are used
for logic solvers, the basic principles of this standard should be applied. This standard also
addresses the safety instrumented system sensors and final elements regardless of the
technology used. This standard is process industry specific within the framework of IEC 61508
(see Annex A).
This standard sets out an approach for safety life-cycle activities to achieve these minimum
standards. This approach has been adopted in order that a rational and consistent technical
policy is used.
In most situations, safety is best achieved by an inherently safe process design. If necessary,
this may be combined with a protective system or systems to address any residual identified
risk. Protective systems can rely on different technologies (chemical, mechanical, hydraulic,
pneumatic, electrical, electronic, programmable electronic). To facilitate this approach, this
standard
• requires that a hazard and risk assessment is carried out to identify the overall safety
requirements;
• requires that an allocation of the safety requirements to the safety instrumented system(s)
is carried out;
• works within a framework which is applicable to all instrumented methods of achieving
functional safety;
• details the use of certain activities, such as safety management, which may be applicable
to all methods of achieving functional safety.
This standard on safety instrumented systems for the process industry
• addresses all safety life-cycle phases from initial concept, design, implementation,
operation and maintenance through to decommissioning;
• enables existing or new country specific process industry standards to be harmonized with
this standard.

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61511-1  IEC:2003 – 15 –
This International Standard is intended to lead to a high level of consistency (for example, of
underlying principles, terminology, information) within the process industries. This should
have both safety and economic benefits.
In jurisdictions where the governing authorities (for example, national, federal, state, province,
county, city) have established process safety design, process safety management, or other
requirements, these take precedence over the requirements defined in this standard.

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61511-1  IEC:2003 – 17 –
Support
Technical
parts
requirements
PART 1 References
Clause 2
Development of the overall safety
PART 1
requirements (concept, scope definition,
hazard and risk assessment)
Definitions and
abbreviations
Clause 8
Clause 3
PART 1
PART 1
Conformance
Allocation of the safety requirements to
Clause 4
the safety instrumented functions and
development of safety requirements
PART 1
specification
Management of
Clauses 9 and 10
functional safety
Clause 5
PART 1
PART 1
Safety life-cycle
Design phase for Design phase for
requirements
safety
safety
Clause 6
instrumented instrumented
PART 1
system software
systems
Clause 12
Clause 11
Verification
Clause 7
PART 1
PART 1
Information
Factory acceptance testing,
requirements
installation and commissioning and
Clause 19
safety validation of safety
instrumented systems PART 1
Clauses 13, 14, and 15
Differences
Annex “A”
PART 1
PART 1
Operation and maintenance,
modification and retrofit, Guideline for the
application of part 1
decommissioning or disposal of
safety instrumented systems
PART 2
Clauses 16, 17, and 18
Guidance for the
determination of the
required safety
integrity levels
PART 3
IEC  3240/02
Figure 1 – Overall framework of this standard

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61511-1  IEC:2003 – 19 –
FUNCTIONAL SAFETY –
SAFETY INSTRUMENTED SYSTEMS
FOR THE PROCESS INDUSTRY SECTOR –

Part 1: Framework, definitions, system,
hardware and software requirements



1 Scope
This International Standard gives requirements for the specification, design, installation,
operation and maintenance of a safety instrumented system, so that it can be confidently
entrusted to place and/or maintain the process in a safe state. This standard has been
developed as a process sector implementation of IEC 61508.
In particular, this standard
a) specifies the requirements for achieving functional safety but does not specify who is
responsible for implementing the requirements (for example, designers, suppliers,
owner/operating company, contractor); this responsibility will be assigned to different
parties according to safety planning and national regulations;
b) applies when equipment that meets the requirements of IEC 61508, or of 11.5 of
IEC 61511-1, is integrated into an overall system that is to be used for a process sector
application but does not apply to manufacturers wishing to claim that devices are suitable
for use in safety instrumented systems for the process sector (see IEC 61508-2 and
IEC 61508-3);
c) defines the relationship between IEC 61511 and IEC 61508 (Figures 2 and 3);
d) applies when application software is developed for systems having limited variability or
fixed programmes but does not apply to manufacturers, safety instrumented systems
designers, integrators and users that develop embedded software (system software) or
use full variability languages (see IEC 61508-3);
e) applies to a wide variety of industries within the process sector including chemicals, oil
refining, oil and gas production, pulp and paper, non-nuclear power generation;
NOTE Within the process sector some applications, (for example, off-shore), may have additional
requirements that have to be satisfied.
f) outlines the relationship between safety instrumented functions an
...