Ergonomics, Standards and Law

Standards and Metrics n Standardisation generally makes people’s lives safer and easier n Standardisation benefits trade n A key aspect of standardisation is Quality Assurance n The main international organisations are –ISO (International Standards Organisation) covering mechanical aspects –IEC (International Electrotechnical Commission) covering electrical aspects n Computing has a joint commission (JTC1) n Governments, professional bodies, companies also produce standards

HCI Standards difficult n HCI standards are important, but difficult to pin down because of the rich variability of human beings ergonomics’ n ISO9241 addresses ergonomics’ requirements for work with VDU’s –Not legally binding minimum safety and health standards n Council Directive from EC addresses minimum safety and health standards for work with visual display equipment legally binding n EC Directive is legally binding; –unless specifically legislated, standards are not minimum standards n 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 n Studies the manner in which the anatomical, physical and psychological needs of workers relate to their immediate working environment n 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 n 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 n Equipment –Use of equipment must not be a source of risk to workers n 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 n 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 n Work desk or surface –sufficiently large, low-reflectance surface and allow flexible arrangement of screen, keyboard, documents and related equipment

EC Directive - Minimum Requirements n 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 n Space requirements –workstation designed to allow user to change position and vary movement n Lighting Requirements –appropriate contrast between screen and background environment –glare minimised by co-ordinating workstation positions with artificial light sources n Reflections and Glare –artificial and natural light sources arranged to eliminate glare –windows fitted with adjustable coverings

EC Directive - Minimum Requirements n Noise –noise emitted from workstations should not distract attention or disturb speech n Heat –equipment must not cause excess heat which discomforts workers n Radiation –reduced to negligible levels n Humidity –adequate level shall be established and maintained

EC Directive - Minimum Requirements n 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 n “ software must be suitable for the task” n “software must be easy to use” n “systems must display information in a format and at a pace which are adapted to users” n “the principles of software ergonomics must be applied”