1、BS EN ISO9241-171:2008ICS 13.180; 35.080NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDErgonomics of human-system interactionPart 171: Guidance on softwareaccessibility (ISO 9241-171:2008)This British Standardwas published under theauthority of the StandardsPol
2、icy and StrategyCommittee on 31 October2009 . BSI 2009ISBN 978 0 580 69257 4Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 9241-171:2008National forewordThis British Standard is the UK implementation of EN ISO9241-171:2008.The UK participation in its preparation was entrusted t
3、o TechnicalCommittee PH/9, Applied ergonomics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a B
4、ritish Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 9241-171July 2008ICS 13.180English VersionErgonomics of human-system interaction - Part 171: Guidanceon software accessibility (ISO 9241-171:2008)Ergonomie de linteraction homme-systme
5、- Partie 171:Lignes directrices relatives laccessibilit aux logiciels(ISO 9241-171:2008)Ergonomie der Mensch-System-Interaktion - Teil 171:Leitlinien fr die Zugnglichkeit von Software (ISO 9241-171:2008)This European Standard was approved by CEN on 28 June 2008.CEN members are bound to comply with t
6、he CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre
7、or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial vers
8、ions.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, Spai
9、n, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Membe
10、rs.Ref. No. EN ISO 9241-171:2008: EBS EN ISO 9241-171:2008EN ISO 9241-171:2008 (E) 3 Foreword This document (EN ISO 9241-171:2008) has been prepared by Technical Committee ISO/TC 159 “Ergonomics“ in collaboration with Technical Committee CEN/TC 122 “Ergonomics” the secretariat of which is held by DI
11、N. 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 January 2009, and conflicting national standards shall be withdrawn at the latest by January 2009. Attention is drawn to the possibility that som
12、e 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 impl
13、ement 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
14、 and the United Kingdom. Endorsement notice The text of ISO 9241-171:2008 has been approved by CEN as a EN ISO 9241-171:2008 without any modification. BS EN ISO 9241-171:2008ISO 9241-171:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv Introduction . vi 1 Scope . 1 2 Normative refer
15、ences . 1 3 Terms and definitions. 2 4 Rationale and benefits of implementing accessibility 8 5 Principles for designing accessible software8 6 Sources of variation in user characteristics 9 7 How to use this part of ISO 9241. 10 7.1 General. 10 7.2 Conformance. 10 8 General guidelines and requireme
16、nts 11 8.1 Names and labels for user-interface elements 11 8.2 User preference settings 14 8.3 Special considerations for accessibility adjustments 16 8.4 General control and operation guidelines17 8.5 Compatibility with assistive technology 21 8.6 Closed systems. 26 9 Inputs . 26 9.1 Alternative in
17、put options . 26 9.2 Keyboard focus. 28 9.3 Keyboard input 29 9.4 Pointing devices . 35 10 Outputs 39 10.1 General output guidelines . 39 10.2 Visual output (displays) . 39 10.3 Text/fonts. 40 10.4 Colour 41 10.5 Window appearance and behaviour .42 10.6 Audio output 45 10.7 Text equivalents of audio
18、 (captions) 47 10.8 Media 47 10.9 Tactile output 48 11 On-line documentation, “Help” and support services 48 11.1 Documentation and “Help” 48 11.2 Support services. 49 Annex A (informative) Overview of the ISO 9241 series. 51 Annex B (informative) List of requirements. 55 Annex C (informative) Sampl
19、e procedure for assessing applicability and conformance 57 Annex D (informative) Activity limitation issues. 68 Annex E (informative) Access features 74 Annex F (informative) Accessibility and usability 83 Bibliography . 85 BS EN ISO 9241-171:2008ISO 9241-171:2008(E) iv ISO 2008 All rights reservedF
20、oreword 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 te
21、chnical 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
22、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
23、 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 f
24、or identifying any or all such patent rights. ISO 9241-171 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4, Ergonomics of human-system interaction. This first edition of ISO 9241-171 cancels and replaces ISO/TS 16071:2003, of which it constitutes a technical revision. I
25、SO 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 layou
26、t 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 guid
27、ance Part 14: Menu dialogues Part 15: Command dialogues BS EN ISO 9241-171:2008ISO 9241-171:2008(E) ISO 2008 All rights reserved v Part 16: Direct manipulation dialogues Part 17: Form filling dialogues Guidance on software individualization and human-centred design process for interactive systems ar
28、e to form the subjects of future parts 129 and 210. 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 Par
29、t 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 m
30、ethods 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 Repor
31、t Part 309: Organic light-emitting diode (OLED) displays 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 for
32、m the subject of a future part 910. BS EN ISO 9241-171:2008ISO 9241-171:2008(E) vi ISO 2008 All rights reservedIntroduction The purpose of this part of ISO 9241 is to provide guidance on the design of the software of interactive systems so that those systems achieve as high a level of accessibility
33、as possible. Designing human-system interactions to increase accessibility promotes increased effectiveness, efficiency and satisfaction for people having a wide variety of capabilities and preferences. Accessibility is therefore strongly related to the concept of usability (see ISO 9241-11). The mo
34、st important approaches to increasing the accessibility of a human-system interface are adopting a human-centred approach to design (see ISO 13407), following a context-based design process, providing the capacity for individualization (see ISO 9241-110), and offering individualized user instruction
35、 and training. It is important to incorporate accessibility goals and features into the design as early as possible, when it is relatively inexpensive compared to the cost of modifying products to make them accessible once they have been designed. As well as providing guidance for achieving that, th
36、is part of ISO 9241 addresses the increasing need to consider social and legislative demands for ensuring accessibility by the removal of barriers that prevent people from participating in life activities such as the use of environments, services, products and information. This part of ISO 9241 is a
37、pplicable to software that forms part of interactive systems used in the home, in leisure activities, in public situations and at work. Requirements and/or recommendations are provided for system design, appearance and behaviour, as well as specific accessibility issues, thereby complementing Intern
38、ational Standards ISO 9241-11, ISO 9241-12, ISO 9241-13, ISO 9241-14, ISO 9241-15, ISO 9241-16 and ISO 9241-17, ISO 9241-110 and ISO 14915, as well as reflecting the goals outlined in ISO Guide 7160. Conforming with the aforementioned International Standard is also important if the goal of accessibi
39、lity is to be achieved. NOTE 1 While the requirements and recommendations of this part of ISO 9241 are generally applicable to all software application domains, additional detailed guidance on the accessibility of Web content (including Web applications) is available from the Web Content Accessibili
40、ty Guidelines (WCAG) 53. 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 groups of people. The intended users of interactive syst
41、ems are consumers or professionals people at home, at school, engineers, clerks, salespersons, Web designers, etc. 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, p
42、eople with disabilities do not form a specific group that can be separated out and then disregarded. The differences in capabilities can 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” 50. Therefor
43、e, 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 who can benefit from new products and services but who experience reduced physical, sensory and cognitive capacities,
44、people with temporary disabilities, such as a person with a broken arm or someone who has forgotten his/her 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. BS EN ISO 9241-171:2
45、008ISO 9241-171:2008(E) ISO 2008 All rights reserved viiWhen designing and evaluating interactive systems there are other terms that are often associated with accessibility. In Europe, the expression design for all or, in North America, universal design 9, address the goal of enabling maximum access
46、 to the maximum number and diversity of users, irrespective of their skill level, language, culture, environment or disability. This does not mean that every product will be usable by every consumer. There will always be a minority of people with severe or multiple disabilities who will need adaptat
47、ions or specialized products. Accessibility as defined in this part of ISO 9241 emphasizes the goals of maximizing the number of users and striving to increase the level of usability that these users experience. This part of ISO 9241 recognizes that some users of software will need assistive technol
48、ogies in order to use a system. In the concept of designing software to be accessible, this includes the capability of a system to provide connections to, and enable successful integration with, assistive technologies, in order to increase the number of people who will be able to use the interactive
49、 system. Guidance is provided on designing software that integrates as effectively as possible with common assistive technologies. It is important to note that accessibility can be provided by a combination of both software and hardware controlled by software. Assistive technologies typically provide specialized input and output capabilities not provided by the system. Software examples include on-screen keyboards that replace physical keyboards, screen-magnificat
