Human factors: Lighting, thermal comfort, working space, noise and vibration
The work environment can impact on a person’s performance in a number of different ways from effects that damage health (heat stress, musculoskeletal disorders); effects that reduce the individual’s ability to perform a task (poor lighting, distraction); to effects that cause dissatisfaction, resistance to change and uncooperative attitudes (“if management think so little of us why should we …”).
Lighting – At its simplest, different levels of lighting are required for different types of work – close, accurate work such as soldering a control panel will require higher light levels than walking down a corridor. However, when considering lighting, a number of different factors need to be considered such as colour, contrast, glare and so on. More information on Lighting.
Thermal comfort – Extremes of temperature (very cold and very hot) can put physiological stress on an individual. Lack of control of the temperature of a workplace (e.g. in an open plan office) can lead to job dissatisfaction and increased incidence of stress and long term sickness absence. More information on Thermal comfort.
Working space – Work rooms should have enough free space to allow people to move about with ease. More information on Working space here.
Noise – For information about controlling noise and about preventing noise induced hearing loss, follow this link. When assessing a task, employers should also consider whether noise might interfere with safety-critical communications. In addition, exposure to high levels of noise can increase individual experience of stress, as may even relatively low noise levels if significantly above background/ambient and if experienced over long periods.
Vibration – Whole body vibration (such as experienced in vehicle cabs) can contribute to lower back pain and fatigue. Some frequencies of vibration can have a negative effect on visual performance. Relatively uncommon effects of low frequency vibration (infrasound) can include throbbing in the head (7Hz) and temporary depressed psychological states. More information on Vibration here.
Lighting an environment is often a complex task principally considered during the design stage of the building (by architects and interior designers). However, lighting should be designed for the tasks that individuals are carrying out within that environment. Guides to lighting can seem very complex, technical documents. However, employers can take some simple steps to ensure people have adequate lighting to carry out their tasks.
Key principles in lighting
Different activities require different levels of light. In general, the more detailed the task, the greater the light requirement. A process control room should be lit at an illuminance of 300 lux, a corridor or walkway may only require 50 lux, whilst studying an engineering drawing may require 750 lux (see HSG38 Lighting at Work).
Where individuals are carrying out different activities, they will need control over their local lighting e.g. a control and instrumentation engineer coming into a process control room lit at 300 lux may need a desk with a lamp to study a wiring diagram.
Studies have shown that giving workers in open plan offices local control of lighting can increase job satisfaction (and decrease the experience of stress).
Directional sources of light can bounce off reflective surfaces such as display screens and cause glare. Using blinds, correcting the angle of the source of light and using glare filters can help control this, as can use of e.g. up-lighting.
All sources of light have a particular colour. Some of these, such as sodium, can make coloured text and diagrams difficult to read.
Sudden contrasts in light levels e.g. coming out of a well-lit area into a dark area or vice versa can be a problem because it takes the eye several seconds to adapt to new lighting conditions. Changes in lighting levels should be made gradually where possible.
Generally lighting is designed when the workplace is empty and without consideration of the shadows cast by equipment e.g. lighting of yards where trailers and containers may be parked. Pedestrian walkways in these areas should have specific lighting.
More information on lighting
- Lighting at work, HSG38, ISBN 07176-12325 (£9.25)
- Chartered Institution of Building Services Engineers (CIBSE)
- Workplace transport: Pages 6-8 of ‘Measuring workplace transport safety performance’ deal with lighting and conspicuity – how well pedestrians can be seen – in controlling the risks of workplace transport (HSL/2005/03)
- Slips, trips and falls: Identifying human factors associated with slip and trip accidents (RR382)
- Falls on stairways – literature review (HSL/2005/10)
- Emergency Lighting: Review of emergency lighting and way-guidance systems for offshore structures (OTH95:499).
People need adequate working space to carry out the tasks they are responsible for. This means they need sufficient space to move about the work area and to access their work station(s) safely. They also need sufficient space to store work equipment including files and documents that they need to use for their work. Work spaces that are perceived by employees to be cramped have a negative effect on job satisfaction and efficiency, and on long-term sickness absence.
Key principles in working space
In general, workrooms should have enough free space to allow people to move about with ease. The Approved Code of Practice to the Workplace (Health, Safety and Welfare) Regulations 1992 gives the following guidance:
The volume of the room when empty, divided by the number of people normally working in it, should be at lease 11 cubic metres. All or part of a room over 3.0m high should be counted at 3.0m high. 11 cubic metres per person is a minimum and may be insufficient depending on the layout, contents and the nature of the work.