CLC IEC/TR 61511-4:2020

Functional safety - Safety instrumented systems for the process industry sector - Part 4: Explanation and rationale for changes in IEC 61511-1 from Edition 1 to Edition 2

This part of IEC 61511, which is a Technical Report, • specifies the rationale behind all clauses and the relationship between them, • raises awareness for the most common misconceptions and misinterpretations of the clauses and the changes related to hem, • explains the differences between Ed. 1 and Ed. 2 of IEC 61511-1 and the reasons behind the changes, • presents high level summaries of how to fulfil the requirements of the clauses, and • explains differences in terminology between IEC 61508-4:2010 and IEC 61511-1 Ed. 2.

Funktionale Sicherheit - PLT-Sicherheitseinrichtungen für die Prozessindustrie - Teil 4: Erläuterung und Gründe der Änderungen in der IEC 61511-1 von Edition 1 zu Edition 2

Sécurité fonctionnelle - Systèmes instrumentés de sécurité pour le secteur des industries de transformation - Partie 4 : Explication et justifications relatives aux modifications apportées entre l’Edition 1 et l’Edition 2 de l’IEC 61511-1

Funkcijska varnost - Sistemi z varnostnimi instrumenti za sektor procesne industrije - 4. del: Pojasnilo in razlogi za spremembe v IEC 61511-1 od 1. do 2. izdaje (IEC/TR 61511-4:2020)

General Information

• Status: Published
• Publication Date: 24-Sep-2020
• 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: CLC/TC 65X - Industrial-process measurement, control and automation
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 25-Sep-2020
• Due Date: 05-Nov-2021
• Completion Date: 25-Sep-2020
• Ref Project: SIST-TP CLC IEC/TR 61511-4:2020 - Functional safety - Safety instrumented systems for the process industry sector - Part 4: Explanation and rationale for changes in IEC 61511-1 from Edition 1 to Edition 2 (IEC/TR 61511-4:2020)

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2020
Funkcijska varnost - Sistemi z varnostnimi instrumenti za sektor procesne
industrije - 4. del: Pojasnilo in razlogi za spremembe v IEC 61511-1 od 1. do 2.
izdaje (IEC/TR 61511-4:2020)
Functional safety - Safety instrumented systems for the process industry sector - Part 4:
Explanation and rationale for changes in IEC 61511-1 from Edition 1 to Edition 2 (IEC/TR
61511-4:2020)
Funktionale Sicherheit - PLT-Sicherheitseinrichtungen für die Prozessindustrie - Teil 4:
Erläuterung und Gründe der Änderungen in der IEC 61511-1 von Edition 1 zu Edition 2
(IEC/TR 61511-4:2020)
Sécurité fonctionnelle - Systèmes instrumentés de sécurité pour le secteur des industries
de transformation - Partie 4 : Explication et justifications relatives aux modifications
apportées entre l'Edition 1 et l'Edition 2 de l'IEC 61511-1 (IEC/TR 61511-4:2020)
Ta slovenski standard je istoveten z: CLC IEC/TR 61511-4:2020
ICS:
25.040.01 Sistemi za avtomatizacijo v Industrial automation
industriji na splošno systems in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT CLC IEC/TR 61511-4

RAPPORT TECHNIQUE
TECHNISCHER BERICHT
September 2020
ICS 13.110; 25.040.01
English Version
Functional safety - Safety instrumented systems for the process
industry sector - Part 4: Explanation and rationale for changes in
IEC 61511-1 from Edition 1 to Edition 2
(IEC/TR 61511-4:2020)
Sécurité fonctionnelle - Systèmes instrumentés de sécurité Funktionale Sicherheit - PLT-Sicherheitseinrichtungen für
pour le secteur des industries de transformation - Partie 4 : die Prozessindustrie - Teil 4: Erläuterung und Gründe der
Explication et justifications relatives aux modifications Änderungen in der IEC 61511-1 von Edition 1 zu Edition 2
apportées entre l'Edition 1 et l'Edition 2 de l'IEC 61511-1 (IEC/TR 61511-4:2020)
(IEC/TR 61511-4:2020)
This Technical Report was approved by CENELEC on 2020-09-14.

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

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC IEC/TR 61511-4:2020 E

European foreword
The text of document (65A/911/DTR), future edition 1 of IEC/TR 61511-4, prepared by SC 65A
"System aspects" of IEC/TC 65 "Industrial-process measurement, control and automation" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as CLC IEC/TR 61511-
4:2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC/TR 61511-4:2020 was approved by CENELEC as a
European Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-192 - International electrotechnical vocabulary - Part 192: - -
Dependability
IEC 61508-4 2010 Functional safety of EN 61508-4 2010
electrical/electronic/programmable electronic
safety-related systems - Part 4: Definitions and
abbreviations (see href="http://www.iec.ch/functionalsafety">Functional
Safety and IEC 61508)
IEC 61511-1 2016 Functional safety - Safety instrumented systems for EN 61511-1 2017
the process industry sector - Part 1: Framework,
definitions, system, hardware and application
programming requirements
+ A1 2017  + A1 2017
ISO/IEC Guide 51 2014 Safety aspects - Guidelines for their inclusion in - -
standards
IEC TR 61511-4 ®
Edition 1.0 2020-02
TECHNICAL
REPORT
Functional safety – Safety instrumented systems for the process industry

sector –
Part 4: Explanation and rationale for changes in IEC 61511-1 from Edition 1 to

Edition 2
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.110, ICS 25.040.01 ISBN 978-2-8322-7870-3

– 2 – IEC TR 61511-4:2020 © IEC 2020
CONTENTS
CONTENTS . 2
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 9
4 Background . 10
5 Management of functional safety (IEC 61511-1 Ed. 2 Clause 5) . 10
5.1 Why is this clause important? . 10
5.2 Common misconceptions . 10
5.3 What was changed from Ed. 1 to Ed. 2 and why? . 11
5.3.1 Existing systems . 11
5.3.2 Change management . 11
5.3.3 Performance metrics and quality assurance . 11
5.3.4 Competency . 12
5.3.5 More requirements for functional safety product and service providers . 12
5.4 Summary on how . 12
6 Safety life cycle (IEC 61511-1 Ed. 2 Clause 6) . 12
6.1 Why is this clause important? . 12
6.2 Common misconceptions . 12
6.3 What was changed from Ed. 1 to Ed. 2 and why? . 13
6.4 Summary on how . 13
7 Verification (IEC 61511-1 Ed. 2 Clause 7). 13
7.1 Why is this clause important? . 13
7.2 Common misconceptions . 13
7.3 What was changed from Ed. 1 to Ed. 2 and why? . 13
7.4 Summary on how . 13
8 Hazard and risk analysis (IEC 61511-1 Ed. 2 Clause 8) . 13
8.1 Why is this clause important? . 13
8.2 Common misconceptions . 14
8.3 What was changed from Ed. 1 to Ed. 2 and why? . 14
8.4 Summary on how . 15
9 Allocation of safety functions to protection layers (IEC 61511-1 Ed. 2 Clause 9) . 15
9.1 Why is this clause important? . 15
9.2 Common misconceptions . 15
9.3 What was changed from Ed. 1 to Ed. 2 and why? . 16
9.3.1 Limits on BPCS protection layers . 16
9.3.2 Requirements for claiming RRF > 10 000 in total for instrumented
safeguards . 16
9.4 Summary on how . 16
10 SIS safety requirements specification (IEC 61511-1 Ed. 2 Clause 10) . 17
10.1 Why is this clause important? . 17
10.2 Common misconceptions . 17
10.3 What was changed from Ed. 1 to Ed. 2 and why? . 18

IEC TR 61511-4:2020 © IEC 2020 – 3 –
10.4 Summary on how . 18
11 Design and engineering (IEC 61511-1 Ed. 2 Clause 11) . 18
11.1 Why is this clause important? . 18
11.2 Common misconceptions . 18
11.3 What was changed from Ed. 1 to Ed. 2 and why? . 19
11.3.1 Hardware fault tolerance . 19
11.3.2 Security risk requirements . 20
11.3.3 Safety manual . 20
11.3.4 Requirements for system behaviour on detection of a fault . 20
11.3.5 Limitations on field device communication design . 21
11.4 Summary on how . 21
12 Application program development (IEC 61511-1 Ed. 2 Clause 12) . 21
12.1 Why is this clause important? . 21
12.2 Common misconceptions . 22
12.3 What was changed from Ed. 1 to Ed. 2 and why? . 22
12.4 Summary on how . 22
13 Factory acceptance test (IEC 61511-1 Ed. 2 Clause 13) . 22
13.1 Why is this clause important? . 22
13.2 Common misconceptions . 23
13.3 What was changed from Ed. 1 to Ed. 2 and why? . 23
13.4 Summary on how . 23
14 Installation (IEC 61511-1 Ed. 2 Clause 14) . 23
14.1 Why is this clause important? . 23
14.2 Common misconceptions . 24
14.3 What was changed from Ed. 1 to Ed. 2 and why? . 24
14.4 Summary on how . 24
15 Validation (IEC 61511-1 Ed. 2 Clause 15) . 24
15.1 Why is this clause important? .
...