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Ergonomics, Standards and Law. Standards and Metrics. Standardisation generally makes people’s lives safer and easier Standardisation benefits trade A key aspect of standardisation is Quality Assurance The main international organisations are
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Standards and Metrics • Standardisation generally makes people’s lives safer and easier • Standardisation benefits trade • A key aspect of standardisation is Quality Assurance • The main international organisations are • ISO (International Standards Organisation) covering mechanical aspects • IEC (International Electrotechnical Commission) covering electrical aspects • Computing has a joint commission (JTC1) • Governments, professional bodies, companies also produce standards
HCI Standards • HCI standards are important, but difficult to pin down because of the rich variability of human beings • ISO9241 addresses ergonomics’ requirements for work with VDU’s • Not legally binding • Council Directive from EC addresses minimum safety and health standards for work with visual display equipment • EC Directive is legally binding; • unless specifically legislated, standards are not • House style guides are designed to provide conformity to minimum standards across a family of products (e.g., MS User Interface Guidelines) • Usually enforceable only through management policy
Ergonomics • Studies the manner in which the anatomical, physical and psychological needs of workers relate to their immediate working environment • Focuses on HCI and how it can be designed to achieve • worker satisfaction • often the last to be considered, if at all • worker safety • worker health • worker productivity
Computer Hazards • Several areas known to have a direct effect on users’ health • RSI • CTS (Carpal Tunnel Syndrome) • both caused by repeated flexing of wrist while using fingers - damages the medial nerve • Lower back injuries
EC Directive - Minimum Requirements • Equipment • Use of equipment must not be a source of risk to workers • Display Screen • Characters well-defined, clearly formed, adequate size and spacing between characters and lines • stable screen image, no flickering • adjustable brightness and contrast esp. to ambient conditions; no reflective glare • display unit must swivel and tilt easily • must be possible to use a separate base or adjustable table for the screen
EC Directive - Minimum Requirements • Keyboard • tiltable, separate from screen • provide support for hands and arms of operator • matt surface to avoid reflective glare • arrangement and characteristics to facilitate use • key symbols shall be adequately contrasted and readable • Work desk or surface • sufficiently large, low-reflectance surface and allow flexible arrangement of screen, keyboard, documents and related equipment
EC Directive - Minimum Requirements • Work Chair • stable; allowing freedom of movement and comfort • adjustable seat height • adjustable seat back (height and tilt) • footrests must be made available for optional use
EC Directive- Minimum Requirements • Space requirements • workstation designed to allow user to change position and vary movement • Lighting Requirements • appropriate contrast between screen and background environment • glare minimised by co-ordinating workstation positions with artificial light sources • Reflections and Glare • artificial and natural light sources arranged to eliminate glare • windows fitted with adjustable coverings
EC Directive - Minimum Requirements • Noise • noise emitted from workstations should not distract attention or disturb speech • Heat • equipment must not cause excess heat which discomforts workers • Radiation • reduced to negligible levels • Humidity • adequate level shall be established and maintained
EC Directive - Minimum Requirements • Operator/Computer Interface • software must be suitable for the task • software must be easy to use and, where appropriate, adaptable to the user’s level of knowledge or experience; no quantitative or qualitative checking facility may be used without knowledge of workers • systems must provide feedback to workers on their performance • systems must display information in a format and at a pace which are adapted to operators • The principles of software ergonomics must be applied, in particular to human data processing
Health and Safety (Display Screen) Equipment Regulations 1992 • “software must be suitable for the task” • “software must be easy to use” • “systems must display information in a format and at a pace which are adapted to users” • “the principles of software ergonomics must be applied”