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Optical Radiation

Optical radiation includes light emitted from all sources including sunlight. Artificial optical radiation includes light in all its forms including ultra-violet, infra-red and laser beams. For work-related health and safety management purposes, sunlight usually only concerns outdoor workers and this is dealt with separately. Also lasers and some applications of ultra-violet light constitute high risk and are covered as separate topics.

Artificial sources of light are present in a very wide range of work-place environments, work activities and research applications at the University. It is useful to rank light sources into high, medium or low hazard categories, this enables risk management to be focused where it is most valuable i.e. on work-place activities where the higher hazards are encountered.

Hazard category definitions, with examples given in the table Optical Radiation Hazards:

  • High Hazard: Artificial optical radiations which may pose a hazard even for a momentary or brief exposure. Harm could include burns or reddening (erythema) of the skin or surface of the eye (photo-keratitis); burns to the retina of the eye (photo-retinitis) and, damage to the eye that may bring about early onset of cataract.
  • Medium Hazard: Artificial optical radiations which do not pose a hazard due to the aversion response of the eyes to very bright light sources or due to thermal discomfort. It also includes lamps that emit infra-red radiation without a strong visual stimulus and which do not pose a near-infrared retinal hazard within 10 seconds
  • Low Hazard: Optical radiation which does not pose a hazard due to normal behavioural limitations on exposure. Also includes lamps that emit infra-red radiation without a strong visual stimulus and which do not pose a near-infrared retinal hazard within 100 seconds.

Risk Assessments should be carried out for all work activities carried out at the University. Low hazards light sources and most medium hazard sources will probably be identified and included in ‘general’ workplace risk assessments. However some light sources in the medium hazard group and all high hazard sources may require a specific risk assessment to be carried out focusing on particular hazard(s).

The risk assessments must identify controls to minimize risk of harmful exposure to as low as reasonably practicable. Control measures to consider when managing artificial optical radiation risks are:-

  • Use an alternative safer light source that can achieve the same result.
  • Use filters, screens, remote viewing, curtains, safety interlocks, dedicated rooms, remote controls.
  • Train workers in best practice and give them appropriate information.
  • Organise work to reduce exposure to workers and restrict access to hazardous areas.
  • Use protective equipment such as clothing, goggles or face shields.
  • Use relevant safety signs.

For further information, refer to the Radiation Protection Officer within the Health and Safety Department. Health and Safety Executive and Health Protection Agency guidance documents are available online.

Table: Optical Radiation Hazards.

Low Hazard Medium Hazard High Hazard
  • Task lighting from ceiling mounted fluorescent strips or filaments with diffusers attached
  • Local task lighting e.g. desk lamps
  • LED remote control devices
  • Vehicle side, brake and indicator lights
  • Photocopiers
  • Computer display screens
  • Task lighting from ceiling mounted fluorescent strips or filaments without diffusers attached.
  • Desk-top projectors
  • High pressure mercury vapour lights
  • Art and entertainment activity floodlights and spotlights provided UV emission is filtered
  • Vehicle headlights
  • Professional projection systems
  • Intense Pulsed Light (IPL, e.g. for cosmetic use)
  • Searchlights
 
  • UV insect traps
  • UV sterilisation
  • UV curing of printing ink
  • UV curing of paints and welds e.g. in motor vehicle repair
  • UV from plasma cutting and welding
  • UV lasers
  • Class 1 lasers
  • Class 1 laser light products
  • Class 1M, 2, 2Mand 3R lasers
  • Class 3B and 4 lasers
  • Laser surgery
  • IR from artificial heaters
  • IR from furnaces
  • IR lasers
  • IR from welding