CLC/TR 62061-1:2010

Guidance on the application of ISO 13849-1 and IEC 62061 in the design of safety-related control systems for machinery

IEC/TR 62061-1:2010 is intended to explain the application of IEC 62061 and ISO 13849-1 in the design of safety-related control systems for machinery.

Anleitung zur Anwendung von ISO 13849-1 und IEC 62061 bei der Gestaltung von sicherheitsbezogenen Steuerungen von Maschinen

Directives relatives à l'application de l'ISO 13849-1 et de la CEI 62061 dans la conception des systèmes de commande des machines relatifs à la sécurité

La CEI/TR 62016-1:2010 a pour objet d'expliquer l'application de la CEI 62061 et de l'ISO 13849-1 dans la conception des systèmes de commande des machines relatifs à la sécurité.

Navodilo za uporabo ISO 13849-1 in IEC 62061 pri načrtovanju z varnostjo povezanih nadzornih sistemov za strojno opremo (IEC/TR 62061-1:2010)

To tehnično poročilo je namenjeno, da razloži uporabo  IEC 62061 in ISO 13849-12 pri načrtovanju z varnostjo povezanih nadzornih sistemov za strojno opremo.

General Information

• Status: Withdrawn
• Publication Date: 05-Aug-2010
• ICS: 13.110 - Safety of machinery
• ICS: 25.040.99 - Other industrial automation systems
• ICS: 29.020 - Electrical engineering in general
• Technical Committee: CLC/TC 44X - Safety of machinery: electrotchnical aspects
• Drafting Committee: IEC/TC 44 - IEC_TC_44
• Parallel Committee: IEC/TC 44 - IEC_TC_44
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 21-Mar-2023
• Completion Date: 23-Sep-2025
• Ref Project: SIST-TP CLC/TR 62061-1:2010 - Guidance on the application of ISO 13849-1 & IEC 62061 in the design of safety-related control systems for machinery (IEC/TR 62061-1:2010)

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2010
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Guidance on the application of ISO 13849-1 & IEC 62061 in the design of safety-related
control systems for machinery (IEC/TR 62061-1:2010)
Anleitung zur Anwendung von ISO 13849-1 und IEC 62061 bei der Gestaltung von
sicherheitsbezogenen Steuerungen von Maschinen (IEC/TR 62061-1:2010)
Directives relatives à l'application de l'ISO 13849-1 et de la CEI 62061 dans la
conception des systèmes de commande des machines relatifs à la sécurité (CEI/TR
62061-1:2010)
Ta slovenski standard je istoveten z: CLC/TR 62061-1:2010
ICS:
13.110 Varnost strojev Safety of machinery
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CLC/TR 62061-1
RAPPORT TECHNIQUE
August 2010
TECHNISCHER BERICHT
ICS 13.110; 25.040.99; 29.020
English version
Guidance on the application of ISO 13849-1 and IEC 62061 in the design
of safety-related control systems for machinery
(IEC/TR 62061-1:2010)
Directives relatives à l'application  Anleitung zur Anwendung von ISO 13849-1
de l'ISO 13849-1 et de la CEI 62061 und IEC 62061 bei der Gestaltung
dans la conception des systèmes von sicherheitsbezogenen Steuerungen
de commande des machines relatifs von Maschinen
à la sécurité (IEC/TR 62061-1:2010)
(CEI/TR 62061-1:2010)
This Technical Report was approved by CENELEC on 2010-07-26.

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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

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

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 62061-1:2010 E

Foreword
The text of document 44/598/DTR, future edition 1 of IEC/TR 62061-1, prepared by IEC TC 44, Safety of
machinery - Electrotechnical aspects, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as CLC/TR 62061-1 on 2010-07-26.
__________
Endorsement notice
The text of the Technical Report IEC/TR 62061-1:2010 was approved by CENELEC as a Technical
Report without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 62061 NOTE  Harmonized as EN 62061.
IEC 60947-5-1:2003 NOTE  Harmonized as EN 60947-5-1:2004 ([not] modified).
IEC 61511-1 NOTE  Harmonized as EN 61511-1.
IEC 61508 series NOTE  Harmonized in EN 61508 series (not modified).
IEC 61800-5-2 NOTE  Harmonized as EN 61800-5-2.
ISO 13849-1 NOTE  Harmonized as EN ISO 13849-1.
ISO 13849-2 NOTE  Harmonized as EN ISO 13849-2.
ISO 14121-1 NOTE  Harmonized as EN ISO 14121-1.
__________
IEC/TR 62061-1 ®
Edition 1.0 2010-07
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Guidance on the application of ISO 13849-1 and IEC 62061 in the design of
safety-related control systems for machinery

Lignes directrices relatives à l'application de l'ISO 13849-1 et de la CEI 62061
dans la conception des systèmes de commande des machines relatifs à la
sécurité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
R
CODE PRIX
ICS 13.110; 25.040.99; 29.020 ISBN 978-2-88912-042-0
– 2 – TR 62061-1 © IEC:2010
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 General .6
3 Comparison of standards.6
4 Risk estimation and assignment of required performance .7
5 Safety requirements specification .7
6 Assignment of performance targets: PL versus SIL.8
7 System design.9
7.1 General requirements for system design using IEC 62061 and ISO 13849-1 .9
7.2 Estimation of PFH and MTTF and the use of fault exclusions .9
D d
7.3 System design using subsystems or SRP/CS that conform to either
IEC 62061 or ISO 13849-1 .10
7.4 System design using subsystems or SRP/CS that have been designed using
other IEC or ISO standards .10
8 Example .10
8.1 General .10
8.2 Simplified example of the design and validation of a safety-related control
system implementing a specified safety-related control function .11
8.3 Conclusion .18
Bibliography.19

Figure 1 – Example implementation of the safety function.11
Figure 2 – Safety-related block diagram.13
Figure 3 – Safety-related block diagram for calculation according to ISO 13849-1 .13
Figure 4 – Logical representation of subsystem D.15

Table 1 – Relationship between PLs and SILs based on the average probability of
dangerous failure per hour.8
Table 2 – Architectural constraints on subsystems' maximum SIL CL that can be
claimed for an SRCF using this subsystem .17

TR 62061-1 © IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDANCE ON THE APPLICATION OF ISO 13849-1 AND IEC 62061
IN THE DESIGN OF SAFETY-RELATED CONTROL SYSTEMS
FOR MACHINERY
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62016-1, which is a technical report, has been prepared jointly by Technical Committee
ISO/TC 199, Safety of machinery, and Technical Committee IEC/TC 44, Safety of machinery –
Electrotechnical aspects. The draft was circulated for voting to the national bodies of both ISO
and IEC. These technical committees have agreed that no modification will be made to this
Technical Report except by mutual agreement .

This Technical Report is published at the ISO as ISO/TR 23849.

– 4 – TR 62061-1 © IEC:2010
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
44/598/DTR 44/608/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site 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.
TR 62061-1 © IEC:2010 – 5 –
INTRODUCTION
This Technical Report has been prepared by experts from both IEC/TC 44/WG 7 and
ISO/TC 199/WG 8 in response to requests from their Technical Committees to explain the
relationship between IEC 62061 and ISO 13849-1. In particular, it is intended to assist users
of these International Standards in terms of the interaction(s) that can exist between the
standards to ensure that confidence can be given to the design of safety-related systems
made in accordance with either standard.
It is intended that this Technical Report be incorporated into both IEC 62061 and ISO 13849-1
by means of corrigenda that reference the published version of this document. These
corrigenda will also remove the information given in Table 1, Recommended application of
IEC 62061 and ISO 13849-1, provided in the common introduction to both standards, which is
now recognized as being out of date. Subsequently, it is intended to merge ISO 13849-1 and
IEC 62061 by means of a JWG of ISO/TC 199 and IEC/TC 44.

– 6 – TR 62061-1 © IEC:2010
GUIDANCE ON THE APPLICATION OF ISO 13849-1 AND IEC 62061
IN THE DESIGN OF SAFETY-RELATED CONTROL SYSTEMS
FOR MACHINERY
1 Scope
2)
This Technical Report is intended to explain the application of IEC 62061 and ISO 13849-1
in the design of safety-related control systems for machinery.
2 General
2.1 Both IEC 62061 and ISO 13849-1 specify requirements for the design and
3)
implementation of safety-related control systems of machinery . The methods developed in
both of these standards are different but, when correctly applied, can achieve a comparable
level of risk reduction.
2.2 These standards classify safety-related control systems that implement safety functions
into levels that are defined in terms of their probability of dangerous failure per hour.
ISO 13849-1 has five Performance Levels (PLs), a, b, c, d and e, while IEC 62061 has three
safety integrity levels (SILs), 1, 2 and 3.
2.3 Product standards (type-C) committees specify the safety requirements for safety-related
control systems and it is recommended that these committees classify the levels of
confidence required for them in terms of PLs and SILs.
2.4 Machinery designers may choose to use either IEC 62061 or ISO 13849-1 depending on
the specific features of the application.
2.5 The selection and use of either standard is likely to be determined by, for example:
– previous knowledge and experience in the design of machinery safety-related control
systems based upon the concept of categories described in ISO 13849-1:1999 can mean
that the use of ISO 13849-1:2006 is more appropriate;
– safety-related control systems based upon media other than electrical can mean that the
use of ISO 13849-1 is more appropriate;
– customer requirements to demonstrate the safety integrity of a machine safety-related
control system in terms of a SIL can mean that the use of IEC 62061 is more appropriate;
– safety-related control systems of machinery used in, for example, the process industries,
where other safety-related systems (such as safety instrumented systems in accordance
with IEC 61511) are characterized in terms of SILs, can mean that the use of IEC 62061 is
more appropriate.
3 Comparison of standards
3.1 A comparison of the technical requirements in ISO 13849-1 and IEC 62061 has been
carried out in respect of the following aspects:

2) This Technical Report considers ISO 13849-1:2006 rather than ISO 13849-1:1999, which has been withdrawn.
3) These standards have been adopted by the European standardization bodies CEN and CENELEC as
ISO 13849-1 and EN 62061, respectively, where they are published with the status of transposed harmonized
standards under the Machinery Directive (98/37/EC and 2006/42/EC). Under the conditions of their publication,
the correct use of either of these standards is presumed to conform to the relevant essential safety
requirements of the Machinery Directive (98/37/EC and 2006/42/EC).

TR 62061-1 © IEC:2010 – 7 –
– terminology;
– risk estimation and performance allocation;
– safety requirements specification;
– systematic integrity requirements;
– diagnostic functions;
– software safety requirements.
3.2 Additionally, an evaluation of the use of the simplified mathematical formulae to
determine the probability of dangerous failures (PFH ) and MTTF according to both
D d
standards has been carried out.
3.3 The conclusions from this work are the following.
– Safety-related control systems can be designed to achieve acceptable levels of functional
4)
safety using either of the two standards by integrating non-complex SRECS (safety-
related electrical control system) subsystems or SRP/CS (safety-related parts of a control
system) designed in accordance with IEC 62061 and ISO 13849-1, respectively.
– Both standards can also be used to provide design solutions for complex SRECS and
SRP/CS by integrating electrical/electronic/programmable electronic subsystems designed
in accordance with IEC 61508.
– Both standards currently have value to users in the machinery sector and benefits will be
gained from experience in their use. Feedback over a reasonable period on their practical
application is essential to support any future initiatives to move towards a standard that
merges the contents of both IEC 62061 and ISO 13849-1.
– Differences exist in detail and it is recognized that some concepts (e.g. functional safety
management) will need further work to establish equivalence between respective design
methodologies and some technical requirements.
4 Risk estimation and assignment of required performance
4.1 A comparison has been carried out on the use of the methods to assign a SIL and/or PL
r
to a specific safety function. This has established that there is a good level of correspondence
between the respective methods provided in Annex A of each standard.
4.2 It is important, regardless of which method is used, that attention be given to ensure that
appropriate judgements are made on the risk parameters to determine the SIL and/or PL that
r
is likely to apply to a specific safety function. These judgements can often best be made by
bringing together a range of personnel (e.g. design, maintenance, operators) to ensure that
the hazards that may be present at machinery are properly understood.
4.3 Further information on the process of risk estimation and the assignment of performance
targets can be found in ISO 14121-1 and IEC 61508-5.
5 Safety requirements specification
5.1 A first stage in the respective methodologies of both ISO 13849-1 and IEC 62061
requires that the safety function(s) to be implemented by the safety-related control system are
specified.
5.2 An assessment should have been performed relevant to each safety function that is to
be implemented by a control circuit by, for example, using ISO 13849-1, Annex A, or
IEC 62061, Annex A. This should have determined what risk reduction needs to be provided

4) Although there is no definition for the term “non-complex” SRECS or SRP/CS this should be considered
equivalent to low complexity in the context of IEC 62061:2005, 3.2.7.

– 8 – TR 62061-1 © IEC:2010
by each particular safety function at a machine and, in turn, what level of confidence is
required for the control circuit that performs this safety function.
5.3 The level of confidence specified as a PL and/or a SIL is relevant to a specific safety
function.
5.4 The following shows the information that should be provided in relation to safety
functions by a product (type-C) standard.
Safety function(s) to be implemented by a control circuit:
Name of safety function
Description of the function
Required level of performance according to ISO 13849-1: PL a to e
r
and/or
Required safety integrity according to IEC 62061: SIL 1 to 3
6 Assignment of performance targets: PL versus SIL
Table 1 gives the relationship between PL and SIL based on the average probability of a
dangerous failure per hour. However, both standards have requirements (e.g. systematic
safety integrity) additional to these probabilistic targets that are also to be applied to a safety-
related control system. The rigour of these requirements is related to the respective PL and
SIL.
Table 1 – Relationship between PLs and SILs based on the average probability
of dangerous failure per hour
Average probability of a dangerous
Performance level (PL) Safety integrity level (SIL)
failure per hour (1/h)
−5 −4
a No special safety requirements
W 10 to < 10
−6 −5
b 1
W 3 × 10 to < 10
−6 −6
c W 10 to < 3 × 10 1
−7 −6
d W 10 to < 10 2
−8 −7
e W 10 to < 10 3
TR 62061-1 © IEC:2010 – 9 –
7 System design
7.1 General requirements for system design using IEC 62061 and ISO 13849-1
The following aspects should be taken into account when designing a SRECS/SRP/CS.
– When applied within the limitations of their respective scopes either of the two standards
can be used to design safety-related control systems with acceptable functional safety, as
indicated by the achieved SIL or PL.
– Non-complex safety-related parts that are designed to the relevant PL in accordance with
ISO 13849-1 can be integrated as subsystems into a safety-related electrical control
system (SRECS) designed in accordance with IEC 62061. Any complex safety-related
parts that are designed to the relevant PL in accordance with ISO 13849-1 can be
integrated into safety-related parts of a control system (SRP/CS) designed in accordance
with ISO 13849-1.
– Any non-complex subsystem that is designed in accordance with IEC 62061 to the
relevant SIL can be integrated as a safety-related part into a combination of SRP/CS
designed in accordance with ISO 13849-1.
– Any complex subsyste
...