A guide to light measurements, legislative requirements and required light levels.
Guide to Light Measurement
ATP Instrumentation has developed a short guide to helping you understand the key terms and legislative requirements related to keeping the workplace adequately lit and safe to work in. The guide provides indicative light levels for a variety of working environments.
We have a variety of light meters and lux meters for testing and logging light levels.
Light Measurements
Light can be measured in many ways. Lux and footcandles are the two most popular measurements chosen by industry. The Lux range is a European standard, and Footcandles are a U.S. scale.
· Lux (Lux) is a unit of illumination of one square metre, which is one metre away from a uniform light source.
· Footcandle (FC) a unit of illumination of one square foot, which is one foot away from a uniform light source.
· 1 Lux = 0.0929 FC 1 FC = 10.76 Lux
Legislative Requirements
Under the Health & Safety at Work Act 1974 an employer has a duty to ensure the health & safety of employees The Act includes a duty to provide lighting to ensure that work can be done safely and that employees health or eyesight are not jeopardised.
The provisions contained in the Management of Safety at Work regulations, especially regulation 3 Risk Assessment, are also relevant.
Regulation no.8 of the Workplace Regulations 1992 states that employers must ensure that:
· Every workplace has suitable & sufficient lighting.
· This should be natural light, so far as is reasonably practicable.
· Suitable & sufficient emergency lighting shall be provided where needed.
Guide to required Light Levels
The amount of light required obviously depends on the type of work being done, but the list below gives an indication of the amount of light required for the different kinds of work:
· movement of people (storage area and plant room) 150 -250 Lux
· no perception of detail (construction, loading bays) 300 - 500 Lux
· limited perception of detail (factories, kitchens) 500 - 750 Lux
· demanding work (inspection, welding, machinery) 750 - 1000 Lux
· repetitive work (electronics, textile production) 1000 - 1500 Lux
· accurate detail (technical offices) 1500 - 3000 Lux
· precision detail (jewellers and goldsmiths) 3000 plus Lux
Guide to typical outdoor light levels Interior levels are much lower than outdoor natural light. Some typical light levels are:- Very bright summer day up to 100,000 Lux Overcast summer day 30,000 to 40,000 Lux Evening televised football match 700 16000 Lux Non-televised football match 200-500 Lux Shady room in daylight 250 to 300 Lux Floodlight on a building 60 Lux Night-time in an urban street 10 Lux Night-time in a car park <1 Lux