SIST EN ISO 9241-20:2009

SLOVENSKI STANDARD
SIST EN ISO 9241-20:2009
01-april-2009
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Ergonomics of human-system interaction - Part 20: Accessibility guidelines for
information/communication technology (ICT) equipment and services (ISO 9241-
20:2008)
Ergonomie der Mensch-System-Interaktion - Teil 20: Leitlinien für die Zugänglichkleit
von Informations- und Kommunikationstechnik und Dienstleistungen (ISO 9241-
20:2008)
Ergonomie de l'interaction homme-système - Partie 20: Lignes directrices sur
l'accessibilité de l'équipement et des services des technologies de l'information et de la
communication (TIC) (ISO 9241-20:2008)
Ta slovenski standard je istoveten z: EN ISO 9241-20:2009
ICS:
13.180 Ergonomija Ergonomics
35.180 Terminalska in druga IT Terminal and other
periferna oprema IT peripheral equipment
SIST EN ISO 9241-20:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9241-20:2009

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SIST EN ISO 9241-20:2009
EUROPEAN STANDARD
EN ISO 9241-20
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2009
ICS 13.180; 35.180

English Version
Ergonomics of human-system interaction - Part 20: Accessibility
guidelines for information/communication technology (ICT)
equipment and services (ISO 9241-20:2008)
Ergonomie de l'interaction homme-système - Partie 20: Ergonomie der Mensch-System-Interaktion - Teil 20:
Lignes directrices sur l'accessibilité de l'équipement et des Leitlinien für die Zugänglichkeit der Geräte und Dienste in
services des technologies de l'information et de la der Informations- und Kommunikationstechnologie (ISO
communication (TIC) (ISO 9241-20:2008) 9241-20:2008)
This European Standard was approved by CEN on 29 December 2008.
CEN 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 Management Centre or to any CEN 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 CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9241-20:2009: E
worldwide for CEN national Members.

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SIST EN ISO 9241-20:2009
EN ISO 9241-20:2009 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 9241-20:2009
EN ISO 9241-20:2009 (E)
Foreword
The text of ISO 9241-20:2008 has been prepared by Technical Committee ISO/TC 159 “Ergonomics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 9241-20:2009 by
Technical Committee CEN/TC 122 “Ergonomics”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by July 2009, and conflicting national standards shall be withdrawn at the
latest by July 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 9241-20:2008 has been approved by CEN as a EN ISO 9241-20:2009 without any
modification.

3

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SIST EN ISO 9241-20:2009

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SIST EN ISO 9241-20:2009

INTERNATIONAL ISO
STANDARD 9241-20
First edition
2008-03-01

Ergonomics of human-system
interaction —
Part 20:
Accessibility guidelines for
information/communication technology
(ICT) equipment and services
Ergonomie de l'interaction homme-système —
Partie 20: Lignes directrices sur l'accessibilité de l'équipement et des
services des technologies de l'information et de la communication (TIC)



Reference number
ISO 9241-20:2008(E)
©
ISO 2008

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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
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All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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ii © ISO 2008 – All rights reserved

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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
Contents Page
Foreword. iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Application . 3
4.1 Principles. 3
4.2 Application framework . 4
4.3 Implementing the recommendations. 4
4.4 Conformance. 5
5 Accessibility . 7
5.1 General. 7
5.2 Context(s) of use and accessibility. 7
5.3 Process . 8
6 Recommendations related to managing development. 8
6.1 Information accessibility policy . 8
6.2 Development accountability . 8
7 Recommendations related to user characteristics . 8
7.1 General. 8
7.2 Vision . 11
7.3 Hearing. 12
7.4 Speech . 14
7.5 Physical capabilities. 14
7.6 Cognitive capabilities. 16
8 Recommendations related to task characteristics. 17
8.1 Performing tasks based on context of use . 17
8.2 Providing alternative ways of performing tasks. 18
8.3 Performing maintenance and other non-task related operations. 18
9 Recommendations related to equipment and service characteristics. 18
9.1 General. 18
9.2 Other standards for ICT equipment and services . 20
9.3 Assistive technologies. 20
9.4 Selection and operation of ICT equipment and services. 21
9.5 Preparation and completion of operation . 21
10 Recommendations related to environmental characteristics . 22
10.1 Operating in a range of environments. 22
10.2 Designing environments. 22
10.3 Impacting the environment. 23
Annex A (informative) Overview of the ISO 9241 series. 24
Annex B (informative) Sample checklist for assessing applicability and conformance of ICT
equipment and services. 28
Annex C (informative) User needs. 33
Bibliography . 42

© ISO 2008 – All rights reserved iii

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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has
been established has the right to be represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9241-20 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4,
Ergonomics of human-system interaction.
ISO 9241 consists of the following parts, under the general title Ergonomic requirements for office work with
visual display terminals (VDTs):
⎯ Part 1: General introduction
⎯ Part 2: Guidance on task requirements
⎯ Part 3: Visual display requirements
⎯ Part 4: Keyboard requirements
⎯ Part 5: Workstation layout and postural requirements
⎯ Part 6: Guidance on the work environment
⎯ Part 7: Requirements for display with reflections
⎯ Part 8: Requirements for displayed colours
⎯ Part 9: Requirements for non-keyboard input devices
⎯ Part 11: Guidance on usability
⎯ Part 12: Presentation of information
⎯ Part 13: User guidance
⎯ Part 14: Menu dialogues
⎯ Part 15: Command dialogues
⎯ Part 16: Direct manipulation dialogues
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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
⎯ Part 17: Form filling dialogues
Guidance on software individualization is to form the subject of a future part 129.
ISO 9241 also consists of the following parts, under the general title Ergonomics of human-system interaction:
⎯ Part 20: Accessibility guidelines for information/communication technology (ICT) equipment and services
⎯ Part 110: Dialogue principles
⎯ Part 151: Guidance on World Wide Web user interfaces
⎯ Part 171: Guidance on software accessibility
⎯ Part 300: Introduction to electronic visual display requirements
⎯ Part 302: Terminology for electronic visual displays
⎯ Part 303: Requirements for electronic visual displays
⎯ Part 304: User performance test methods
⎯ Part 305: Optical laboratory test methods for electronic visual displays
⎯ Part 306: Field assessment methods for electronic visual displays
⎯ Part 307: Analysis and compliance test methods for electronic visual displays
⎯ Part 308: Surface-conduction electron-emitter displays (SED) [Technical Report]
⎯ Part 400: Principles and requirements for physical input devices
⎯ Part 410: Design criteria for physical input devices
⎯ Part 920: Guidance on tactile and haptic interactions
Framework for tactile and haptic interaction is to form the subject of a future part 910.
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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
Introduction
The number of people using information/communication technologies (ICT) equipment and services, which
combine hardware, software and network technologies, is increasing, as is the variety of ICT equipment and
services. Our everyday lives are filled by such equipment and services.
This part of ISO 9241 is intended to help developers enable ICT equipment and services (and forthcoming
novel or innovative equipment and services) so that they can be used by the widest range of people,
regardless of their capabilities or disabilities, limitations or culture.
This part of ISO 9241 is based on the current understanding of the characteristics of individuals who have
particular physical, sensory and/or cognitive impairments. However, accessibility is an issue that affects many
people. The users of interactive systems are consumers or professionals with roles such as home occupiers,
school pupils, engineers, clerks, salespersons and web designers. The individuals in such target groups vary
significantly as regards physical, sensory and cognitive abilities and each target group will include people with
different abilities. Thus people with disabilities do not form a specific group that can be separated out and then
disregarded. The differences in capabilities may arise from a variety of factors that serve to limit the capability
to engage in the activities of daily living, and are a “universal human experience”. Therefore, accessibility
addresses a widely defined group of users including
⎯ people with physical, sensory and cognitive impairments present at birth or acquired during life,
⎯ elderly people (a growing percentage of the population), who can benefit from new products and services
but who experience reduced physical, sensory and cognitive capacities,
⎯ people with temporary disabilities, such as a person with a broken arm or someone without his or her
reading glasses, and
⎯ people who experience difficulties in particular situations, such as a person who works in a noisy
environment or has both hands occupied by other activities.
This part of ISO 9241 is prepared as guidance to secure and improve accessibility to ICT equipment, software
and services when they are used by people within the widest range of capabilities. It presents:
a) a framework based on the ergonomic concept of context of use, and
b) principles for the accessibility of ICT equipment and services.
Their presentation is intended to assist the users of this part of ISO 9241 in the consideration of accessibility
issues. It also describes major product attributes with design examples, provides information for the planning,
design and development of ICT equipment and services and acquisition and evaluation of ICT equipment and
services. It recognizes the importance of following general ergonomic guidance as well as the more
accessibility-specific guidance found in this and other accessibility-specific standards in achieving full use of
ICT equipment, software and services.
While many of the requirements and recommendations in this part of ISO 9241 also apply outside the domain
of accessibility, they are especially important to this domain. The checklist of Annex B has also been included
to help users examine the accessibility features of ICT equipment and services.


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SIST EN ISO 9241-20:2009
INTERNATIONAL STANDARD ISO 9241-20:2008(E)

Ergonomics of human-system interaction —
Part 20:
Accessibility guidelines for information/communication
technology (ICT) equipment and services
1 Scope
This part of ISO 9241 is intended for use by those responsible for planning, designing, developing, acquiring,
and evaluating information/communication technology (ICT) equipment and services. It provides guidelines for
improving the accessibility of ICT equipment and services such that they will have wider accessibility for use
at work, in the home, and in mobile and public environments. It covers issues associated with the design of
equipment and services for people with a wide range of sensory, physical and cognitive abilities, including
those who are temporarily disabled, and the elderly.
A detailed design for particular equipment or a service can be developed based on its recommendations. If a
specific detailed standard exists concerning the accessibility of equipment or services, then it can be used in
conjunction with that more specific standard. Where such standards are not available, this part of ISO 9241
can then form the basis for the design of the accessibility features of ICT equipment and services.
It also provides general guidelines for acquiring and evaluating ICT equipment and services, including both
hardware and software aspects of information processing equipment, electronic communication facilities,
office machines, and other similar technologies and services, used at work, in the home, and in mobile and
public environments.
In addition, it gives important information about context of use. Accessibility is increased by expanding the
range of contexts where equipment and services can be used. Context of use can result from the various
components of the equipment or service, including user, task and equipment (hardware, software and
materials) characteristics, as well as those of physical and social environments. Context of use can be
considered when planning, designing, developing, acquiring and evaluating ICT equipment and services.
NOTE This part of ISO 9241 is a high-level standard applicable to all ICT equipment and services, therefore, detailed
descriptions specific to equipment or services have been avoided. It can be referred to for the prevention of barriers to
trade or the movement of people in respect of each national, regional and international standardization activity in this area.
More specific recommendations on software accessibility are contained in ISO 9241-171.
2 Normative references
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.
ISO 9241-5, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 5:
Workstation layout and postural requirements
ISO 9241-11:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 11:
Guidance on usability
ISO 9241-12, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 12:
Presentation of information
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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
ISO 9241-13, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 13: User
guidance
ISO 9241-14, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 14: Menu
dialogues
ISO 9241-15, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 15:
Command dialogues
ISO 9241-16, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 16: Direct
manipulation dialogues
ISO 9241-17, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 17: Form
filling dialogues
ISO 9241-110:2006, Ergonomics of human-system interaction — Part 110: Dialogue principles
ISO 9241-151, Ergonomics of human-system interaction — Part 151: Guidance on World Wide Web user
1)
interfaces
1)
ISO 9241-171, Ergonomics of human-system interaction — Part 171: Guidance on software accessibility
ISO 9241-300, Ergonomics of human-system interaction — Part 300: Introduction to electronic visual display
1)
requirements
ISO 9241-302, Ergonomics of human-system interaction — Part 302: Terminology for electronic visual
1)
displays

ISO 9241-410, Ergonomics of human-system interaction — Part 410: Design criteria for physical input devices
ISO 13407:1999, Human-centred design processes for interactive systems
ISO 14915 (all parts), Software ergonomics for multimedia user interfaces
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
accessibility
〈interactive systems〉 usability of a product, service, environment or facility by people within the widest range
of capabilities
NOTE 1 The concept of accessibility addresses the full range of user capabilities and is not limited to users who are
formally recognized as having disability.
NOTE 2 The usability-oriented concept of accessibility aims to achieve levels of effectiveness, efficiency and
satisfaction that are as high as possible considering the specified context of use, while paying attention to the full range of
capabilities within the user population.
3.2
assistive technology
hardware or software, added to or incorporated within a system, which increases accessibility for an individual

1) To be published.
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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
3.3
context of use
users, tasks, equipment (hardware, software and materials), and the physical and social environments in
which a product is used
[ISO 9241-11:1998, definition 3.5]
3.4
information/communication technology
ICT
technology for gathering, storing, retrieving, processing, analysing and transmitting information
3.5
interactive system
combination of hardware and software components that receive input from, and communicate output to, a
human user in order to support his or her performance of a task
[ISO 13407:1999, definition 2.1]
NOTE The term “system” is often used rather than “interactive system”.
3.6
screen reader
assistive technology in combination with information available via the operating system that allows users to
navigate through windows, determine the state of controls, and read text through Braille or text-to-speech
conversion
3.7
usability
extent to which a product can be used by specified users to achieve specified goals with effectiveness,
efficiency and satisfaction in a specified context of use
[ISO 9241-11:1998, definition 3.1]
3.8
user
〈ICT〉 individual interacting with the ICT equipment or service
NOTE Adapted from ISO 9241-11:1998, definition 3.7 and ISO 9241-110:2006, definition 3.8.
4 Application
4.1 Principles
Design for accessibility should adhere to the following principles.
a) Suitability for the widest range of use
Suitability for the widest range of use involves designing with the objective of producing solutions that will
be useful, acceptable and available to the widest range of users within the user population, taking
account of their special abilities, variations in their capabilities, the diversity of their tasks, and their
differing environmental, economic and social circumstances.
b) Equitable use
Achieving equitable use will ensure that solutions designed to increase accessibility do not result in loss
of privacy, increased risks to personal safety or security, or the stigmatization of individuals, and that
solutions provide the same means of use for all users that are identical whenever possible; equivalent
when not.
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SIST EN ISO 9241-20:2009
ISO 9241-20:2008(E)
c) Robustness
Robustness involves supporting a wide range of options both in terms of the features provided by ICT
equipment or services and in terms of the ability to connect additional ICT equipment, software, and/or
services.
NOTE 1 Although it is not feasible to make all ICT operable without add-on assistive technologies, the application of
this part of ISO 9241 can help designers develop equipment and services that increases accessibility without the use of
assistive technologies. Additionally, by providing the necessary interface information, its application will enable assistive
software and devices to operate effectively and efficiently when used.
NOTE 2 ICT can promote integration of assistive technologies by providing information that can be read by those
technologies, and by communicating through standard app
...