ISO 9241-1:1992

IS0
1 "TER NATIONAL
STA N DAR D 9241 -1
First edition
1992-06-01
Ergonomic requirements for office work with
visual display terminals (VDTs) -
Part 1:
General introduction
Exigences ergonomiques pour travail de bureau avec terminaux à écrans
de visualisation (TEV) -
Partie I: Introduction générale
Reference number
IS0 9241-1:1992(E)

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IS0 9241 -1 :I 992( E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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, govern-
mental and non-governmental, in liaison with ISO, also take part in the
work. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75% of the member
bodies casting a vote.
International Standard IS0 9241-1 was prepared by Technical Committee
ISO/TC 159, Ergonomics, Sub-Committee SC 4, Signals and controls.
IS0 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 fask requirements
- Part 3: Visual display requirements
- Part 4: Keyboard requirements
- Part 5: Workstation layout and postural requirements
- Part 6: Environmental requirements
- Part 7: Display requirements with reflections
- Part 8: Requirements for displayed colours
- Part 9: Requirements for non-keyboard input devices
- Part IO: Dialogue principles
6 IS0 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 CH-I211 Genève 20 Switzerland
Printed in Switzerland
ii

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IS0 9241-1:1992(E)
- Part 1 I: Usability statements
- Part 12: Presentation of information
- Part 13: User guidance
- Part 14: Menu dialogues
- Part 15: Command dialogues
- Part 16: Direct manipulation dialogues
- Part 17: Form filling dialogues
Annexes A and B of this part of IS0 9241 are for information only.
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IS0 9241-1:1992(E)
Introduction
IS0 9241 provides the ergonomic requirements for visual display ter-
minals (VDTs) in which display screen equipment is used for office tasks
including text and data processing.
The purpose of IS0 9241 is to promote good ergonomic design of VDT
work and thus to ensure that VDT users can operate display screen
equipment safely, efficiently, effectively and comfortably. In practice, this
can only be achieved by careful design of the VDTs themselves, the
workplaces and working environments in which they are used and the
way the VDT work is designed, organized and managed. IS0 9241 is
therefore intended for all those involved in ensuring safe and effective
VDT work. Much of IS0 9241 deals with the design of the VDT itself and
is provided to help designers and manufacturers to develop
ergonomically-sound visual display terminals. This information is also
relevant to purchasers who wish to specify VDTç for applications or
systems in their own organizations. It is also relevant to those who wish
to assess the suitability of existing or proposed equipment.
IS0 9241 also deals with the VDT workplace, the VDT working environ-
ment and the organization and management of VDT work. This infor-
mation is intended for VDT users and for those responsible for their
supervision and management.
IS0 9241 is concerned with the users operating the VDT rather than the
design of the VDT per se. Unlike many standards for computer equip-
ment, the emphasis is therefore on specifying factors affecting the user
performance rather than specifying the physical characteristics of the
equipment which might be assumed to give rise to the desired human
performance outcome.
The specification and assessment of user performance is dependent on
appropriate test methods and these form an important component of
IS0 9241. However it is recognised that not every user of IS0 9241 will
have the resources necessary to conduct user performance tests and
so, where possible, specific design guidance is given, based on existing
knowledge and current technology, which is known to achieve the same
result. Some aspects of VDT use and design are not amenable to such
user performance specification, for example the design of VDT tasks,
and here IS0 9241 provides guidelines to assist manufacturers, design-
ers, users and managers.
of the complexities of VDT ergonomics and the unfamiliar and
In view
multipurpose nature of IS0 9241, it has been organized into a number
of parts, each dealing with a different aspect of VDT work. Unless oth-
erwise stated, each part of IS0 9241 deals with one aspect of VDT use
and makes the assumption that the other aspects are as specified in the
other parts. Overall, the requirements specified and the tests described
are designed to be appropriate to typical office VDT circumstances.
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INTERNATIONAL STANDARD IS0 9241-1:1992(E)
Ergonomic requirements for of‘fice work with visual display
terminals (VDTs) -
Part 1:
Genera I introduction
1 Scope
2 Principles of the user performance
approach
One of the main concerns of ergonomics is in en-
suring that equipment is fit for human use. In gen-
This part of IS0 9241 applies to the ergonomic re-
eral this involves matching the design of any
quirements for the use of visual display terminals for
controls, displays, material to be handled,
office tasks. For the purposes of this part of
workplace, working environment and tasks to the
IS0 9241, office tasks include text and data pro-
characteristics, strengths and limitations of the po-
cessing but not computer-aided design tasks (CAD)
tential user under the appropriate working environ-
or industrial process control tasks.
ment. Failure to take account of human limitations
can lead to errors, reduced performance, discomfort
NOTE 1 VDTs typically comprise a display unit (often a
and perhaps risk of injury. Failure to take account
cathode ray tube), a keyboard and some associated elec-
of human strengths can be wasteful, reduce ef-
tronics and control circuitry. The VDT may be a terminai
ficiency and result in boring, tedious work.
to a larger system or may be a self-contained computer.
Other equipment including printers and communications
In practice, all equipment users are different and it
devices may be connected and located at the VDT
is important to understand in what ways they vary
workplace or remotely.
and to quantify the variation so that it is taken into
account in the design. Good ergonomic design is
This part of IS0 9241:
important in any equipment designed for human use
but it is especially important when the use is inten-
- introduces IS0 9241 as a whole;
sive or if the accuracy or speed of the user’s per-
formance is critical.
- describes the basis of the user performance ap-
proach;
VDT use is often both intensive and sensitive to the
user’s performance and forms a significant part of
- gives an overview of the first six parts of
many office workers’ jobs. increasingly, users, their
IS0 9241; and
representatives and managers are concerned with
ensuring that VDTs are designed to appropriate
I - provides guidance on how to use IS0 9241
ergonomic standards.
I
Annex A lists the planned further parts of IS0 9241
Design guidance relevant to current technology is
l and summarizes their contents.
useful to designers and has been included within
IS0 9241. However, major emphasis is placed on
IS0 9241 does not cover electrical safety or radiation
specifying the factors affecting the performance of
emission; some aspects of these are covered by the
the user. Thus, for example, IS0 9241 sets legibility
IEC publications listed in annex B.
requirements for displays in terms of the perform-
ance which users should be able to achieve in per-
forming typical office tasks. This user performance
1

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IS0 9241-1:1992(E)
approach deals directly with the ergonomics re-
f) a degree of individual control over the pace of
quirements and should be much less dependent on
work;
the current state of technology than product stan-
g) some cohesion so that the task forms an under-
dards.
standable part of the work of the organization;
However, the user performance approach depends
on sound methods of testing which include detailed
h) an opportunity for the individuals to use their
specifications of which ergonomic factors are im-
skills and experience, and to gain new skills;
portant for a particular item of equipment, how they
should be measured including where appropriate
i) sufficient feedback on the task performance in
the test equipment to be used, what sample of sub-
terms which are meaningful and helpful to the
jects is appropriate, what experimental conditions
user.
are relevant and what level of performance is ex-
pected. All of these points are dealt with in each of
IS0 9241-2 provides guidance on how task require-
the relevant parts of IS0 9241. ments can be identified and specified within individ-
ual organizations and how task requirements can
It is recognised that some users of IS0 9241 will not
be incorporated into the system design and im-
have the resources to carry out the test methods in
plementation process.
full and are only using current technology in a rela-
tively straightforward way. In order to help such us-
3.3 Part 3 Visual display requirements
ers, prescriptive guidance has been provided which
should achieve the specified level of user perform-
IS0 9241-3 deals with the characteristics of the vis-
ance with current technology.
ual display which determine its effectiveness in
presenting an image to the user. The user perform-
ance objective is that the user should be able to
3 Overview of the first six parts of
detect and recognize the image accurately, quickly
IS0 9241 and without discomfort.
The display characteristics which influence de-
3.1 Part 1: General introduction
tection and recognition performance are identified.
Where appropriate, design guidance on the mini-
The general introduction contains information about
mum, maxim
...