ISO 9241


ISO 9241 is a multi-part standard from the International Organization for Standardization covering ergonomics of human-system interaction and related, human-centered design processes. It is managed by the ISO Technical Committee 159. It was originally titled Ergonomic requirements for office work with visual display terminals .
From 2006 onwards, the standards were retitled to the more generic Ergonomics of Human System Interaction.
As part of this change, ISO is renumbering some parts of the standard so that it can cover more topics, e.g. tactile and haptic interaction. For example, two zeros in the number indicate that the document under consideration is a generic or basic standard. Fundamental aspects are regulated in standards ending with one zero. A standard with three digits other than zero in the number regulate specific aspects. The first part to be renumbered was part 10.
Part 1 is a general introduction to the rest of the standard. Part 2 addresses task design for working with computer systems. Parts 3 to 9 deal with physical characteristics of computer equipment. Part 110 and parts 11 to 19 deal with usability aspects of software, including Part 110 and Part 11.

Ergonomics of Human System Interaction

The revised multipart standard is numbered in series as follows:
  • 100 series: Software ergonomics
  • 200 series: Human system interaction processes
  • 300 series: Displays and display related hardware
  • 400 series: Physical input devices - ergonomics principles
  • 500 series: Workplace ergonomics
  • 600 series: Environment ergonomics
  • 700 series: Application domains - Control rooms
  • 900 series: Tactile and haptic interactions
Within those series, the standard currently includes the following parts:
  • Part 100: Introduction to standards related to software ergonomics
  • Part 110: Dialogue principles
  • Part 112: Principles for the presentation of information
  • Part 125: Guidance on visual presentation of information
  • Part 129: Guidance on software individualization
  • Part 151: Guidance on World Wide Web user interfaces
  • Part 143: Forms
  • Part 154: Interactive voice response applications
  • Part 161: Guidance on visual user interface elements
  • Part 171: Guidance on software accessibility
  • Part 210: Human-centred design for interactive systems
  • 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 for electronic visual displays
  • 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
  • Part 309 : Organic light-emitting diode displays
  • Part 310 : Visibility, aesthetics and ergonomics of pixel defects
  • Part 400: Principles and requirements for physical input devices
  • Part 410: Design criteria for physical input devices
  • Part 910: Framework for tactile and haptic interaction
  • Part 920: Guidance on tactile and haptic interactions

    ISO 9241-110

The first edition of ISO 9241-110 was issued in 2006. In 2020, a revised version was published, titled "Ergonomics of human-system interaction — Part 110: Interaction principles". The core idea of the standard was not changed. Interaction principles are design guidelines for user interfaces that embody principles. The seven interaction principles are applicable to the design of any user interface, whether it is software, hardware or a combination of both.
Some principles have been refined to be more appropriate to today's possibilities or forms of interaction and User Engagement has been introduced as a new interaction principle. For each interaction principle, general design recommendations are given, which helps to follow them when designing user interfaces.
  • Suitability for the user's tasks
  • Self-descriptiveness
  • Conformity with user expectations
  • Learnability
  • Controllability
  • Use error robustness
  • User engagement
The 2020 revision tied the earlier principle of individualisation into the principle of controllability, and introduced the principle of user engagement.

ISO 9241-210

Part 210: Human-centred Design; This part, updated in 2019, provides guidance on human-system interaction as holistic approach to plan, research, conceptualize, specify, design, develop, deploy and maintain interactive systems throughout their life cycle. It also covers the importance of sustainability and accessibility within the human-centered approach.
With its introduction in 2008, it revised ISO 13407, Human-centred design for interactive systems.

ISO-9241-302, 303, 305, 307:2008 pixel defects

Of particular interest to the lay computer user are the definitions of flat-panel TV and monitor pixel defects provided in the series of standards. These identify three classes for measuring pixel defects in flat panel monitors:
  • Class 0 panels are completely defect-free, including no full pixel or sub-pixel defects.
  • Class 1 panels permit any or all of the following:
  • * 1 full bright pixel
  • * 1 full dark pixel
  • * 2 single or double bright or dark sub-pixels
  • * 3 to 5 “stuck on” or “stuck off” sub-pixels
  • Class 2 panels permit any or all of the following:
  • * 2 full bright pixels
  • * 2 full dark pixels
  • * 5-10 single or double bright or dark sub-pixels.
  • Class 3 panels permit any or all of the following:
  • * 5 full bright pixels
  • * 15 full dark pixels
  • * 50 single or double sub-pixels stuck on or off
As of 2010, most premium branded panel manufacturers specify their products as Class 0, expecting a small number of returns due to early failure where a particular item fails to meet Class 0 but would meet Class 1. Budget panel manufacturers tend to specify their products as Class 1. Most premium branded finished product manufacturers tend to specify their products as meeting Class 1 even when they have a Class 0 specified panel inside. Some premium branded finished product manufacturers have started to specify their products as Class 0 or offer a Class 0 guarantee for an additional premium.

Previous version

ISO 9241 was originally titled Ergonomic requirements for office work with visual display terminals and consisted of the following parts:
  • 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: Display requirements with reflections
  • Part 8: Requirements for displayed colors
  • Part 9: Requirements for non-keyboard input devices
  • Part 10: Dialogue principles
  • 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
  • Part 17: Form filling dialogues
  • Part 20: Accessibility guidelines for ICT equipment and services

    ISO 9241-1

Part 1: Ergonomic requirements for office work with visual display terminals : General Introduction
This part introduces the multi-part standard ISO 9241 for the ergonomic requirements for the use of visual display terminals for office tasks and explains some of the basic underlying principles. It provides some guidance on how to use the standard and describes how conformance to parts of ISO 9241 should be reported.

ISO 9241-2

Part 2: Guidance on task requirements
This part deals with the design of tasks and jobs involving work with visual display terminals. It provides guidance on how task requirements may be identified and specified within individual organisations and how task requirements can be incorporated into the system design and implementation process.

ISO 9241-3

Part 3: Visual display requirements
This part specifies the ergonomics requirements for display screens which ensure that they can be read comfortably, safely and efficiently to perform office tasks. Although it deals specifically with displays used in offices, it is appropriate to specify it for most applications that require general purpose displays to be used in an office-like environment.

ISO 9241-4

Part 4: Keyboard requirements
This part specifies the ergonomics design characteristics of an alphanumeric keyboard which may be used comfortably, safely and efficiently to perform office tasks. Keyboard layouts are dealt with separately in various parts of ISO/IEC 9995: 1994 Information Processing - Keyboard Layouts for Text and Office Systems

ISO 9241-5

Part 5: Workstation layout and postural requirements
This part specifies the ergonomics requirement for a Visual Display Terminal workplace which will allow the user to adopt a comfortable and efficient posture.

ISO 9241-6

Part 6: Environmental requirements
This part specifies the ergonomics requirements for the Visual Display Terminal working environment which will provide the user with comfortable, safe and productive working conditions.

ISO 9241-7

Part 7: Display requirements with reflections
This part specifies methods of measurement of glare and reflections from the surface of display screens, including those with surface treatments.

ISO 9241-8

Part 8: Requirements for displayed colors
This part specifies the requirements for multicolour displays which are largely in addition to the monochrome requirements in Part 3.

ISO 9241-9

Part 9: Requirements for non-keyboard input devices
This part specifies the ergonomics requirements for non-keyboard input devices which may be used in conjunction with a visual display terminal. It also includes a suggestion for a user-based performance test as an alternative way of showing conformance. The standard covers such devices as the mouse, trackball and other pointing devices, but it does not address voice input.