The duty to provide and maintain light
The WHSWR impose and absolute duty on an employer to ensure that every workplace has both ‘suitable’ and ‘sufficient’ lighting.
All these requirements must be taken into account in any risk assessment process undertaken by the employer.
Assessing workplace lighting
Any assessment of lighting in the workplace should take account of the following aspects:
HSC approved code of practice
The ACOP makes the following points about lighting in the workplace.
The quantity of light
The current criteria for deciding what is sufficient lighting are the recommended average and minimum measured illuminance published in HSE Guidance Notes HS(G)38: Lighting at Work.
Light flow or ‘illuminance’ is the quantity of light emitted from a light source such as fluorescent strip or a bulb. Lighting is measured quantitatively in Lux. Average and minimum measure illuminances (in Lux) are based on both the general activity undertaken and the type of work location and/or work carried out. No maximum illuminance level is specified. See tables 5 & 6 below.
|General activity||Typical locations/types of work||Average illuminance (Lux)||Minimum measured illuminance (Lux)|
|Movement of people, machines & vehicles||Lorry parks, corridors, circulation routes||20||5|
|Movement of people, machines and vehicles in hazardous areas, rough work not requiring any perception of detail (1)||Construction site clearance excavation and soil work, docks, loading bays, bottling and canning plants||50||20|
|Work requiring limited perception of detail (2)||Kitchens, factories, assembling large components, potteries||100||50|
|Work requiring perception of detail||Office, sheet metal work, bookbinding||200||100|
|Work requiring perception of fine detail||Drawing offices, factories assembling electronic components, textile production||500||200|
|Situations to which recommendation applies||Typical location||Maximum ration of illuminances
|Maximum ration of illuminances
|Where each task is individually lit and the area around the task is lit to a lower illuminance||Local lighting in an office||5||1|
|Where 2 working areas are adjacent, but one is lit to a lower illuminance than the other||Localised lighting in a works store||5||1|
|Where 2 working areas are lit to different illuminances and are separated by a barrier but there is frequent movement between them||A storage area inside a factory and loading bay outside||10||1|
Lighting of the work area and adjacent areas is important. Large differences between them may cause visual discomfort or even affect safety in places where there is frequent movement of traffic. This problem arises most often where local or localised lighting in an interior exposes a person to a range of illuminances for a long time, or where there is movement between interior and exterior working areas exposing a person to sudden changes of illuminance.
To guard against danger and discomfort the recommendations in the Table should be followed.
Recommended lighting levels
The Chartered Institution of Building Services Engineers (CIBSE) recommend the following lighting levels (measurements in Lux):
Table : Recommended lighting levels
Conference rooms, executive offices
Computer and data preparation rooms
|Banks and building societies
Counter, office area
Reception, cashiers and porters' desks
Bars, coffee bars, dining rooms, grill rooms, restaurants, lounges
Cloakrooms, baggage, rooms
Small retail outlets
Covered arcades and malls
The quality of lighting
Average illuminance and minimum measured illuminance relate to the quantity of lighting for a particular task. For lighting to be suitable, it is necessary to consider the qualitative aspects of lighting and the design of lighting.
The following aspects are significant in the design of lighting for work stations and installations.
This is the effect of light which causes impaired vision or discomfort, and is experienced when parts of the visual field are excessively bright compared with the general surroundings. Glare, in its various forms, can be a contributory factor in accidents
Glare is experienced in three forms:
a) Disability glare-the visually disabling effect caused by bright bare lamps directly in the line of sight;
b) Discomfort glare- the visual discomfort caused mainly by too much contrast of brightness between an object and its background; and
c) Reflected glare-where the reflection of bright light sources on wet or shiny work surfaces, such as plated metal or glass, can almost conceal the detail in or behind the surface which is glinting.
The way in which light is distributed or spread is an important feature of lighting design. The British Zone Method classifies luminaries (light fittings) according to the way in which they distribute light from BZ1 (all light down in a narrow column) to BZ10 (light in all directions).
This is particularly important where it may be necessary to illuminate danger areas and hazards arising from machinery.
This refers to the appearance of an object under a given light source compared with its colour under a reference illuminant e.g. natural light. Colour rendition enables correct perception of the colour. Incorrect perception of colour by an individual can be a contributory factor in incidents involving, for instance, electricity supply e.g. incorrect wiring of a fitting.
This is the projection of light in many directions with no directional predominance. Diffused lighting, in many cases, will reduce or soften the output from a particular source and so limit the amount of glare that may be encountered from bare fittings. To be effective, diffusers must be cleaned on a regular basis.
There is an absolute duty on employers to maintain the workplace, equipment, systems and devices ‘in an efficient state, in efficient working order and in good repair’. This includes lighting systems and fittings.
A planned preventative maintenance programme, including the keeping of records of assessment and maintenance, is necessary to ensure compliance with this general duty. On this basis, lighting maintenance should feature in an organisations planned preventative maintenance programme. This should include regular cleaning and replacement of lamps, maintenance of systems and fittings, together with regular assessment of illuminance using a standard photometer (light meter) in order to ensure these illuminances are maintained.
Emergency lighting arrangements
Emergency lighting may be necessary in any part of a workplace where danger can arise from a failure of the lighting system. In the event of the artificial lighting system failing, the emergency lighting arrangements should come into operation. This takes two forms:
a) Standby lighting – which enables essential work to continue; and
b) Escape lighting – which enables a building to be evacuated safely.
Current fire safety legislation requires the lighting of escape routes.
Much will depend upon the nature of the work undertaken and the risks arising form same. It may be between 5% and 100% of the illuminance level currently provided.
The general recommendation is that escape lighting should reach the necessary illuminance level within 5 seconds of the failure of the principal lighting system, although if the occupants are familiar with the layout of the premises this may be increased by 15 seconds.
Escape lighting may take the form of battery-powered installations designed to operate for between 1 and 3 hours according to the size of the premises and problems arising from evacuation. Other systems powered by generators will operate for as long as the generator functions and should at least match the operating times of the battery-powered installations.