When a general lighting proves inadequate for a specific task it is necessary to provide a localised light in order to obtain the required type and degree of illumination. This can be grouped in four types:
- Fixed units.
- Flexible arm bracket (either high or low voltage).
- Portable hand lamps (preferably low voltage).
- Fluorescent tubes.
Where task lights are extensively used, general light should provide minimum brightness which is equal to square root of the illumination (when expressed in lm/ft²) of task light with a minimum of 6 lm/ft²
The use of fixed light is confined to bench/desk work where working positions are fixed. Mains voltage can be used with safety as units are mounted out of reach. In some cases projector type of unit also can be used as they can be mounted well clear of the working area.
Flexible arms bracket find their greatest use with machine tools, but here care should be used and low voltage should be given by means of small transformer. In cases where movable light is used, care should be exercised to see that glare to adjacent workers is minimized. For this purpose special low surface brightness visors and reflector extensions should be used.