SIST EN IEC 62508:2025
(Main)Guidance on human aspects of dependability (IEC 62508:2025)
Guidance on human aspects of dependability (IEC 62508:2025)
IEC 62508: 2025 provides guidance on current knowledge and practice concerning dependability in an operational environment, in terms of the humans, teams and organizations involved in conducting the work. It is part of a suite of IEC standards that are intended to address the dependability of both the technical and human elements of equipment and organizations.
This document describes the human elements of a typical operational system, and the importance of those elements to overall dependability. It also describes the means of assessing how well these elements are functioning, and general concepts on how the reliability of humans can be improved. These elements typically include the individual workers, the groups or teams into which they are organized, the interfaces between humans and technical systems, and the overall organization.
The following guidance is applicable to any industry that depends on human-systems interactions involving the technology, software, or systems of work required to support the production and safety objectives of an organization. This document primarily addresses complex technical systems, but some parts are also applicable to the manufacturing of industrial and consumer products. Principles for design of the human-machine interface (usability) are described, and further information can be found in the technical literature and in relevant product standards. Although this document does not specifically cover worker health or safety, the application of this document can raise related issues, particularly in process safety, which is closely associated with system reliability.
This second edition cancels and replaces the first edition published in 2010. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) The emphasis on user-centred design in the previous edition was reduced in favour of a greater emphasis on human dependability in an existing operational environment.
b) The emphasis on human error and error-rate determination methods was reduced in favour of a greater emphasis on means of providing organizational support for the workforce in their execution of required tasks.
c) Where appropriate, discussions of human factors in an operational environment were aligned with current theory, terminology and practice.
Leitlinien zu den menschlichen Aspekten der Zuverlässigkeit (IEC 62508:2025)
Lignes directrices relatives aux facteurs humains dans la sûreté de fonctionnement (IEC 62508:2025)
L'IEC 62508: 2025 fournit des recommandations concernant les connaissances et pratiques actuelles en matière de sûreté de fonctionnement dans un environnement opérationnel, par rapport aux êtres humains, aux équipes et aux organisations impliquées dans l'exécution du travail. Il fait partie d'une série de normes IEC destinées à traiter de la sûreté de fonctionnement des éléments techniques et humains des équipements et des organisations.
Le présent document décrit les éléments humains d'un système opérationnel type et l'importance de ces éléments pour la sûreté de fonctionnement globale. Il décrit également les moyens d'évaluer le bon fonctionnement de ces éléments, ainsi que des concepts généraux sur la manière dont la fiabilité humaine peut être améliorée. Ces éléments comprennent généralement les différents travailleurs, les groupes et équipes au sein desquels ils sont répartis, les interfaces entre les êtres humains et les systèmes techniques, et l'organisation globale.
Les recommandations suivantes s'appliquent à toute industrie qui dépend des interactions homme-système impliquant la technologie, les logiciels ou les systèmes de travail nécessaires pour soutenir les objectifs de production et de sécurité d'une organisation. Le présent document concerne principalement les systèmes techniques complexes, mais certaines parties s'appliquent également à la fabrication de produits industriels et de consommation. Les principes de conception de l'interface homme-machine (utilisabilité) sont décrits, et des informations complémentaires peuvent être obtenues dans la documentation technique et dans les normes de produits pertinentes. La santé et la sécurité des travailleurs ne sont pas spécifiquement couvertes par le présent document, mais son application peut soulever des questions connexes, notamment en ce qui concerne la sécurité des processus, qui est étroitement liée à la fiabilité des systèmes.
Cette deuxième édition annule et remplace la première édition parue en 2010. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) l'accent mis sur la conception centrée sur l'utilisateur dans l'édition précédente a été réduit au profit d'une plus grande importance accordée aux facteurs humains de la sûreté de fonctionnement dans un environnement opérationnel existant;
b) l'accent mis sur l'erreur humaine et les méthodes de détermination du taux d'erreur a été réduit au profit d'une plus grande importance accordée aux moyens de fournir un soutien organisationnel au personnel dans l'exécution des tâches exigées;
c) le cas échéant, les discussions sur les facteurs humains dans un environnement opérationnel ont été alignées sur la théorie, la terminologie et la pratique actuelles.
Napotki o človeških vidikih zanesljivosti (IEC 62508:2025)
Ta dokument vsebuje napotke o trenutnem znanju in praksi glede zanesljivosti v operativnem okolju, in sicer z vidika ljudi, ekip in organizacij, ki sodelujejo pri opravljanju dela. Je del skupine standardov IEC, namenjenih obravnavi zanesljivosti tehničnih in človeških elementov opreme in organizacij.
Ta dokument opisuje človeške elemente tipičnega operativnega sistema in njihov pomen za splošno zanesljivost. Opisuje tudi načine za ocenjevanje delovanja teh elementov in splošne koncepte o tem, kako je mogoče izboljšati zanesljivost ljudi. Ti elementi običajno vključujejo posamezne delavce, skupine ali ekipe, v katere so organizirani, vmesnike med ljudmi in tehničnimi sistemi ter celotno organizacijo.
Napotki se uporabljajo za vse panoge, ki so odvisne od interakcij med človekom in sistemi, vključno s tehnologijo, programsko opremo ali delovnimi sistemi, potrebnimi za doseganje proizvodnih in varnostnih ciljev organizacije. Ta dokument obravnava predvsem kompleksne tehnične sisteme, nekateri deli pa se uporabljajo tudi za proizvodnjo industrijskih in potrošniških izdelkov. V njem so opisana načela za načrtovanje vmesnika človek-stroj (uporabnost), dodatne informacije pa so na voljo v tehnični literaturi in ustreznih standardih za izdelke. Čeprav ta dokument ne zajema posebej zdravja ali varnosti delavcev, lahko njegova uporaba sproži s tem povezana vprašanja, zlasti glede varnosti procesov, ki je tesno povezana z zanesljivostjo sistema.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2025
Nadomešča:
SIST EN 62508:2010
Napotki o človeških vidikih zanesljivosti (IEC 62508:2025)
Guidance on human aspects of dependability (IEC 62508:2025)
Leitlinien zu den menschlichen Aspekten der Zuverlässigkeit (IEC 62508:2025)
Lignes directrices relatives aux facteurs humains dans la sûreté de fonctionnement (IEC
62508:2025)
Ta slovenski standard je istoveten z: EN IEC 62508:2025
ICS:
03.120.01 Kakovost na splošno Quality in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 62508
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2025
ICS 03.120.01 Supersedes EN 62508:2010
English Version
Guidance on human aspects of dependability
(IEC 62508:2025)
Lignes directrices relatives aux facteurs humains dans la Leitlinien zu den menschlichen Aspekten der
sûreté de fonctionnement Zuverlässigkeit
(IEC 62508:2025) (IEC 62508:2025)
This European Standard was approved by CENELEC on 2025-07-24. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
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,
Türkiye 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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62508:2025 E
European foreword
The text of document 56/2074/FDIS, future edition 2 of IEC 62508, prepared by TC 56 "Dependability"
was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-08-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-08-31
document have to be withdrawn
This document supersedes EN 62508:2010 and all of its amendments and corrigenda (if any).
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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62508:2025 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60300-1 NOTE Approved as EN IEC 60300-1
IEC 60812 NOTE Approved as EN IEC 60812
IEC 61025 NOTE Approved as EN 61025
IEC 62402 NOTE Approved as EN IEC 62402
IEC 62502 NOTE Approved as EN 62502
IEC 62740 NOTE Approved as EN 62740
IEC 62960 NOTE Approved as EN IEC 62960
ISO 6385:2016 NOTE Approved as EN ISO 6385:2016 (not modified)
ISO 9000 NOTE Approved as EN ISO 9000
ISO 9241-1:1997 NOTE Approved as EN ISO 9241-1:1997 (not modified)
ISO 9241-2 NOTE Approved as EN 29241-2
ISO 9241-5 NOTE Approved as EN ISO 9241-5
ISO 9241-6 NOTE Approved as EN ISO 9241-6
ISO 9241-11 NOTE Approved as EN ISO 9241-11
ISO 9241-13 NOTE Approved as EN ISO 9241-13
ISO 9241-14 NOTE Approved as EN ISO 9241-14
ISO 9241-20 NOTE Approved as EN ISO 9241-20
ISO 9241-110 NOTE Approved as EN ISO 9241-110
ISO 9241-125 NOTE Approved as EN ISO 9241-125
ISO 9241-143 NOTE Approved as EN ISO 9241-143
ISO 9241-171 NOTE Approved as EN ISO 9241-171
ISO 9241-210:2019 NOTE Approved as EN ISO 9241-210:2019 (not modified)
ISO 9241-220 NOTE Approved as EN ISO 9241-220
ISO 9241-300 NOTE Approved as EN ISO 9241-300
ISO 9241-302 NOTE Approved as EN ISO 9241-302
ISO 9241-303 NOTE Approved as EN ISO 9241-303
ISO 9241-304 NOTE Approved as EN ISO 9241-304
ISO 9241-305 NOTE Approved as EN ISO 9241-305
ISO 9241-306 NOTE Approved as EN ISO 9241-306
ISO 9241-307 NOTE Approved as EN ISO 9241-307
ISO/TR 9241-309 NOTE Approved as CEN ISO/TR 9241-309
ISO/TR 9241-311 NOTE Approved as CEN ISO/TR 9241-311
ISO 9241-400 NOTE Approved as EN ISO 9241-400
ISO 9241-410 NOTE Approved as EN ISO 9241-410
ISO/TS 9241-411 NOTE Approved as CEN ISO/TS 9241-411
ISO/TR 9241-810 NOTE Approved as CEN ISO/TR 9241-810
ISO 9241-920 NOTE Approved as EN ISO 9241-920
ISO 11064-1 NOTE Approved as EN ISO 11064-1
ISO 11064-2 NOTE Approved as EN ISO 11064-2
ISO 11064-3 NOTE Approved as EN ISO 11064-3
ISO 11064-4 NOTE Approved as EN ISO 11064-4
ISO 11064-5 NOTE Approved as EN ISO 11064-5
ISO 11064-6 NOTE Approved as EN ISO 11064-6
ISO 11064-7 NOTE Approved as EN ISO 11064-7
ISO/IEC/TR 25060 NOTE Approved as CEN ISO/TR 25060
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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-192 2015 International electrotechnical vocabulary - - -
Part 192: Dependability
IEC 62508 ®
Edition 2.0 2025-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Guidance on human aspects of dependability
Lignes directrices relatives aux facteurs humains dans la sûreté de
fonctionnement
ICS 03.120.01 ISBN 978-2-8327-0487-5
IEC 62508:2025-06(en-fr)
IEC 62508:2025 © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms. 11
4 Dependability elements of a socio-technical system . 11
4.1 Overview . 11
4.2 Task element . 13
4.3 Human element . 14
4.3.1 Role of humans in a system . 14
4.3.2 Dependability characteristics of humans . 15
4.4 Machine element . 15
4.5 Organization and team elements . 16
4.5.1 Overview . 16
4.5.2 Teamwork and operational environment . 16
4.5.3 Organizational environment and structure . 16
4.5.4 Physical environment . 16
4.5.5 Cultural environment . 17
4.6 Feedback within the socio-technical system . 17
5 Human-factors influence on dependability . 18
5.1 Overview . 18
5.2 Influence of the human element on dependability . 19
5.2.1 Overview . 19
5.2.2 Human strengths and limitations in an operational environment . 19
5.2.3 Performance shaping factors (human factors) . 20
5.2.4 External human factors . 21
5.2.5 Internal human factors . 21
5.2.6 Information processing . 22
5.3 Influence of the machine element on dependability. 22
5.4 Influence of the task element on dependability . 23
5.4.1 General. 23
5.4.2 Allocation of tasks to humans versus machines to optimize
dependability . 23
6 Human dependability programme: Identifying the steps to improve human
dependability . 23
6.1 Overview . 23
6.2 Analysing dependability failures to define countermeasures . 24
6.2.1 Overview . 24
6.2.2 Human failures . 24
6.2.3 Machine failures . 26
6.2.4 Human – System interaction failures . 26
6.3 Analysis of dependability data . 27
6.4 Improving human dependability . 27
6.4.1 Minimizing risk due to human-related failures. 27
6.4.2 Human decision-making. 28
IEC 62508:2025 © IEC 2025
6.5 Improving machine dependability through a human-factors approach . 28
6.6 Improving socio-technical system dependability . 29
7 Human dependability at each life-cycle stage . 29
7.1 Overview of human dependability aspects of life-cycle stages . 29
7.2 Concept and definition stage . 30
7.2.1 Concept stage . 30
7.2.2 Human-centred design planning . 31
7.2.3 System requirements . 31
7.2.4 Human-centred design requirements . 31
7.3 Design and development stage . 32
7.3.1 Human-centred design principles . 32
7.3.2 Human-centred design guidelines . 32
7.3.3 Human-centred design activities . 34
7.3.4 Integrating human dependability into design and development . 34
7.3.5 Human dependability analysis in design and development . 35
7.4 Realization and implementation stage . 35
7.5 Operations and maintenance stage. 36
7.6 Enhancement stage . 37
7.7 Retirement or decommissioning stage. 37
Annex A (informative) Examples of human reliability analysis (HRA) methods . 38
Annex B (informative) Summary of human-oriented design activities and their impact
on system dependability . 42
B.1 Overview . 42
B.2 Automation . 42
B.3 Design for maintainability . 43
B.4 Human-machine interface . 43
B.5 Incorporation of displays, controls, and alarm functions . 44
B.6 Incorporation of input devices . 44
B.7 Environment . 45
B.8 Safety. 45
B.9 Security . 45
Annex C (informative) Processes for human-centred design . 46
Bibliography . 53
Figure 1 – Components and interaction of a socio-technical system . 12
Figure 2 – Performance shaping factors (PSFs) that can influence human dependability . 21
Figure 3 – Model of typical human information processing . 22
Figure 4 – Hierarchy of human failures . 25
Figure 5 – System life cycle . 30
Figure 6 – Human-centred design activities . 34
Table 1 – People who influence dependability . 14
Table A.1 – HRA methods and their application . 38
Table B.1 – Automation . 42
Table B.2 – Design for maintainability . 43
Table B.3 – Human-machine interface . 43
Table B.4 –Incorporation of displays, controls, and alarm functions . 44
IEC 62508:2025 © IEC 2025
Table B.5 – Incorporation of input devices. 44
Table B.6 – Environment . 45
Table B.7 – Safety . 45
Table B.8 – Security . 45
Table C.1 – Examples of methods and techniques that contribute to human-centred
design . 46
IEC 62508:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Guidance on human aspects of dependability
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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62508 has been prepared by IEC Technical Committee 56: Dependability. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2010. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The emphasis on user-centred design in the previous edition was reduced in favour of a
greater emphasis on human dependability in an existing operational environment.
b) The emphasis on human error and error-rate determination methods was reduced in favour
of a greater emphasis on means of providing organizational support for the workforce in
their execution of required tasks.
c) Where appropriate, discussions of human factors in an operational environment were
aligned with current theory, terminology and practice.
IEC 62508:2025 © IEC 2025
The text of this International Standard is based on the following documents:
Draft Report on voting
56/2074/FDIS 56/2096A/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IEC 62508:2025 © IEC 2025
INTRODUCTION
This document is intended as a basic guide for managers, engineers and other professionals.
It concerns good practice for improving dependability of humans in an operational environment,
as well as optimizing the interactions between humans and equipment, software, and
organizational systems. Modern workplaces often involve the integration of humans with
complex technologies and production systems. This document is intended to assist
management to:
• understand the basis for human dependability, including designing equipment and systems
to minimize human error rather than overly relying on the workforce to act correctly,
• assess the risks related to human performance in an operational environment, and
• implement changes in an operational environment in order to improve the effectiveness of
personnel in relation to the technology and systems with which they interact.
One objective in implementing the guidelines in this document is to facilitate the optimization of
interactions between humans and equipment, software, facilities, services and organizational
systems. A second objective is to reduce the potential for failures to occur that can adversely
affect production, equipment maintenance, safety or the well-being of the workforce. Towards
this end, guidance on applicable methods and metrics are included for assessing the risks
associated with human dependability.
This document is not intended as a handbook or theoretical guide to the fields of human factors
or human-systems interactions. These are available elsewhere, and some useful references
are listed in the bibliography. Rather, it is intended as a tool for managers and engineers who
are tasked with designing, assessing or controlling the human and technical elements of their
area of responsibility.
Rather than being a review of human "undependability", the aim is to describe the elements of
operational systems that positively contribute to human performance. This document provides
an awareness of the relative importance of these elements to dependability, and the tools for
assessing how well they are functioning in the organization, and how they can be enhanced.
In accordance with other dependability standards (cf. IEC 60300-1), the term ‘human reliability’
will refer to qualitative and, when appropriate, quantitative measures of human performance.
The term "human dependability" will be applied more broadly to the ability of humans to conduct
a task or job as-required and when-required, with an outcome that satisfies agreed stakeholder
expectations. The concepts of "maintainability" and "supportability" will still apply, but in the
broader context of the organizational factors required for maintaining and supporting human
performance.
Although knowledge of the field of human factors in the workplace and principles of human-
centred design would be useful, this document will help managers, engineers and other
professionals to identify the areas of their responsibility that would benefit from improvement in
terms of human dependability, and to put in place interventions designed to optimize human
performance.
This document primarily addresses complex technical systems, but some parts are also
applicable to manufacturing of mass-produced industrial and consumer products. Principles for
the design of the human-machine interface (usability) are described, and further information
can be found in technical literature and in relevant product standards.
IEC 62508:2025 © IEC 2025
1 Scope
This document provides guidance on current knowledge and practice concerning dependability
in an operational environment, in terms of the humans, teams and organizations involved in
conducting the work. It is part of a suite of IEC standards that are intended to address the
dependability of both the technical and human elements of equipment and organizations.
This document describes the human elements of a typical operational system, and the
importance of those elements to overall dependability. It also describes the means of assessing
how well these elements are functioning, and general concepts on how the reliability of humans
can be improved. These elements typically include the individual workers, the groups or teams
into which they are organized, the interfaces between humans and technical systems, and the
overall organization.
The following guidance is applicable to any industry that depends on human-systems
interactions involving the technology, software, or systems of work required to support the
production and safety objectives of an organization. This document primarily addresses
complex technical systems, but some parts are also applicable to the manufacturing of industrial
and consumer products. Principles for design of the human-machine interface (usability) are
described, and further information can be found in the technical literature and in relevant
product standards. Although this document does not specifically cover worker health or safety,
the application of this document can raise related issues, particularly in process safety, which
is closely associated with system reliability.
2 Normative references
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.
IEC 60050-192:2015, International Electrotechnical Vocabulary (IEV) – Part 192: Dependability,
available at www.electropedia.org
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-192 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
IEC 62508:2025 © IEC 2025
3.1.1
dependability
ability to perform as and when required
Note 1 to entry: A dependable item or service is one where there is justified confidence that it operates as desired
and satisfies agreed stakeholder expectations.
Note 2 to entry: In most cases, the term "dependability" is used as an umbrella term to express its core attributes
of reliability, maintainability, and supportability and the attribute of availability derived therefrom. In some cases,
attributes such as resilience, recoverability, durability, integrity, safety, security, trustworthiness are also included in
or overlap with dependability.
Note 3 to entry: In order to express the ability to perform, requirements are specified in terms of the functions to be
performed, when the performance is to be achieved, and the life profile conditions, as specified by customers, users,
or stakeholders.
Note 4 to entry: The attributes of dependability can be expressed qualitatively or quantitatively.
Note 5 to entry: It is also a common practice to use the term "dependability" in the context of a subject of study or
discipline.
[SOURCE: IEC 60050-192:2015, 192-01-22, modified – The domain has been
deleted and the Notes to entry have been replaced with new Notes to entry.]
3.1.2
ergonomics
human factors
HF
scientific discipline concerned with the understanding of interactions among human and other
elements of a system, and the profession that applies theory, principles, data and methods to
design in order to optimize human well-being and overall system performance
[SOURCE: ISO 6385:2016, 2.3]
3.1.3
human error resistance
ability of a system to minimize the probability of human error occurring
3.1.4
human aspects
abilities, limitations, and other human characteristics that are relevant to the design, operation
or maintenance of systems and their components, affecting overall system performance
3.1.5
human-centred design
approach to systems design and development that aims to make interactive systems more
usable by focusing on the use of the system, applying human factors, ergonomics and usability
knowledge and techniques
Note 1 to entry: Usable systems provide a number of benefits including improved productivity, enhanced user well-
being, avoidance of stress, increased accessibility, and reduced risk of harm.
Note 2 to entry: This standard uses the term "human-oriented design" to refer to the need to take account of humans
in system design but retains the term "human-centred design" used in ISO standards to refer to the specific principles
and activities.
Note 3 to entry: The term "human-centred design" is used rather than "user-centred design" in order to emphasize
that this document addresses a number of stakeholders, not just those typically considered as users. However, in
practice, these terms are often used synonymously.
[SOURCE: ISO 9241-210:2019, 3.7, modified – Note 2 to entry has been added, and Notes 1
and 3 to entry have been renumbered.]
IEC 62508:2025 © IEC 2025
3.1.6
human error
discrepancy between the human action taken or omitted, and that intended or required
[SOURCE: IEC 60050-192:2015, 192-03-14, modified – the example has been omitted.]
3.1.7
human error probability
probability that an operator will fail in an assigned task
Note 1 to entry: This can be based on the ratio of the average number of errors within a certain task in relation to
the overall number of error possibilities for this type of task.
Note 2 to entry: Human error probability is expressed as a distribution, where the distribution is determined in
accordance with the human variations and situational variations under which the task is to be conducted.
3.1.8
human failure
occurrence of a deviation from the human action that is necessary for achieving an objective,
regardless of the reason for that deviation
Note 1 to entry: For any particular system or situation, the range of human failures is the combination of human
errors and violations that lead to system failures or hazardous outcomes, or both.
3.1.9
human-oriented design
user-centric approach to design by adapting technologies to meet human performance
requirements, account for human limitations, achieve mental comfort and enhance overall
system performance
3.1.10
human reliability
ability of human beings to complete a task under given conditions within a defined period of
time and within the acceptance limits
3.1.10.1
human dependability
ability of humans to conduct a task or job as required and when required, with an outcome that
satisfies agreed stakeholder expectations
3.1.11
human reliability analysis
human reliability assessment
systematic process to evaluate human reliability
Note 1 to entry: Evaluation methods can be qualitative alone or can be expanded to provide quantitative results.
3.1.12
machine
non-human component of a system that assists humans to achieve the organization's output
Note 1 to entry: Machine includes hardware and software used to perform physical, computational, decisional and
creative tasks.
3.1.13
mistake
deficiency or failure in the judgemental or inferential process involved in the selection of an
objective or in specification of the means to achieve it, irrespective of whether or not the actions
run according to plan
IEC 62508:2025 © IEC 2025
3.1.14
performance shaping factors
characteristics of the task, workplace or organizational environment that influence the outcome
of human activities
3.1.15
requirement
statement which translates or expresses a need and its associated constraints and conditions
Note 1 to entry: Requirements exist at different levels in the system structure.
Note 2 to entry: A requirement is an expression of one or more particular needs in a very specific, precise and
unambiguous manner.
Note 3 to entry: A requirement always relates to a system, software or service, or other item of interest.
Note 4 to entry: A requirement is a statement where evidence or assurance of compliance can be provided.
[SOURCE: ISO/IEC/IEEE 29148:2018, 3.1.19, modified – Note 4 to entry has been added.]
3.1.16
situational awareness
human perception of the elements in the environment within a specified or implied volume of
time and space, the comprehension of their meaning and the projection of their status in the
near future
3.1.17
socio-technical system
set of interrelated or interacting technical, human and organizational elements which produce
an output generally based on inputs and tasks
EXAMPLES A system producing IT, a factory production line, an office processing paperwork or a mine extracting
minerals.
Note 1 to entry: In the context of dependability, a system will have:
– a defined purpose expressed in terms of intended functions,
– stated conditions of operation or use, and
– defined boundaries.
Note 2 to entry: The structure of a system can be hierarchical.
Note 3 to entry: For some systems, such as information technology products, data is an important part of the
system.
3.1.18
task
defined activity that is assigned to a person or machine in order to achieve a specific goal
Note 1 to entry: These activities can be physical, perceptual or cognitive.
Note 2 to entry: While goals are independent of the means used to achieve them, tasks describe particular means
of achieving goals.
3.1.19
violation
deliberate, but not necessarily malicious, deviation from practices deemed necessary
3.1.20
workplace
permanent, temporary, physical, or virtual location where tasks are accomplished
EXAMPLE A component of a socio-technical system.
IEC 62508:2025 © IEC 2025
3.2 Abbreviated terms
ASEP accident sequence evaluation programme
ATHEANA a technique for human error analysis
CAD computer-aided design
CAHR connectionism assessment of human reliability
CARA controller action reliability assessment
CPC common performance condition
CREAM cognitive reliability and error analysis method
EFC error-forcing context
ESAT Experten-System zur Aufgaben-Taxonomie (expert system for task taxonomy)
FMEA failure modes and effects analysis
FMECA failure modes effects and criticality analysis
HEART human error assessment and reduction technique
HEP human error probability
HF human factors
HRA Human Reliability Analysis
HR human resources
HSI human-system interactions
ILS integrated logistics support
IT information technology
MERMOS méthode d'évaluation de la réalisation des missions opérateur pour la sûreté
(method for evaluating the accomplishment of an operator's safety tasks)
ORE operator reliability experiments
PSF performance shaping factor
RR reliability rating
SHERPA systematic human error reduction and prediction approach
SLI success likelihood index
SLIM success likelihood index methodology
SPAR-H standardized plant analysis risk-human reliability analysis
THERP technique for human error rate prediction
4 Dependability elements of a socio-technical system
4.1 Overview
Human actions can have a strong influence on the dependability of the whole system and the
quality of the output. Therefore, important benefits accrue from consideration of human aspects,
among which are preventing failures, improving system performance, promoting safe systems
of work, increasing reliability and enhancing cost effectiveness. A system that requires human
interaction involves human(s), machine(s) and the organizational and physical environment in
which they operate. The dependability of the system and the efficiency and effectiveness with
which the output or tasks of the system are achieved depend on each component of the system
individually and the interactions between them (Figure 1).
IEC 62508:2025 © IEC 2025
Figure 1 – Components and interaction of a socio-technical system
The elements shown in Figure 1 are as follows.
• Task element: what the work system is expected to achieve (4.2).
• Human or team element: person or people who perform the task (4.3).
• Machine: technical component of the system designed to support achievement of the work
system tasks by interacting with the human element (4.4).
• Team and organizational element: structure of the social and organizational operating
environment, and systems for organizing the human element (4.5).
• Physical and cultural environment: factors in the operational environment that can influence
the humans and organization (4.5.3).
• Output: that which the system achieves with the required level of effectiveness, efficiency
and satisfaction.
• Feedback: information exchanged between elements of the system to indicate successful
or unsuccessful achievement of the output (4.6).
• In addition, all the elements of the system are influenced by performance shaping factors
(PSFs) (5.2.2).
Dependability is usually characterized in terms of reliability, maintainability, supportability, and
availability. In some cases, attributes such as resilience, recoverability, durability, and integrity,
are also included in dependability. Dependability is critical at all life-cycle stages. Dependability
also affects other attributes such as safety and environmental protection, where the inability to
perform a required function can result in safety-related or environmentally damaging
consequences. Dependability should therefore be actively managed throughout the system life
cycle. Clause 7 describes the details of human dependability at each life-cycle stage.
IEC 62508:2025 © IEC 2025
NOTE The dependability objective can be different from the safety objective at each life-cycle stage because
dependability is defined as "ability to perform as and when required" and safety is "freedom from unacceptable risk".
Although this document does not directly refer to safety nor environmental issues, much of the guidance in this
document can also be applied to them.
4.2 Task element
Achieving the goals of a socio-technical system can require the satisfactory completion of many
tasks. The objective of the socio-technical system is to complete these tasks with a desired
effectiveness and output quality, within an efficient timeframe, in accordance with defined
processes and procedures (including safe methods of work).
Tasks within an operational environment vary depending on the work system. Tasks can be
value-adding or non-value adding; both can affect dependability. Examples of different types of
tasks include:
• design of the system (not covered by this document);
• construction tasks e.g. assembling, connecting, testing and commissioning;
• operational tasks e.g. sampling, monitoring, changing configurations, adjustment of
parameters, removing impediments;
• maintenance tasks e.g. inspection, fault-finding, cleaning, repair or replacement, calibration,
lubrication, updating;
• travelling and movement within the system;
• transferring information e.g. communication, reporting, handovers and briefings;
• supervision e.g. planning, issuing directions to personnel, monitoring and correcting;
• training, instruction and assessment e.g. determining skills required, determining skills
level, assigning to appropriate training courses and materials.
The allocation of tasks between humans and technology (such as machines and software)
should be based on performance criteria, such as performance demands (e.g. work constraints,
speed of response, frequency of action, need for judgement and decision-making) and relative
capabilities of humans versus technology (se
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