Office Health and Safety Hazards: Lighting

The Kenya Occupational Safety and Health Act (OSHA) 2007 requires every workplace in which persons are working or passing should have effective provision for securing and maintaining sufficient and suitable lighting, whether natural or artificial. The Act also provides that all glazed windows and skylights used for the lighting of workrooms should be kept clean on both the inner and outer surface and free from obstruction. Contravention of these provisions by any occupier / employer is an offense under the Act.

Kenya however lacks specific guidelines on the measure of adequate lighting for different workplaces. The UK HSE document HSG38 (Lighting at Work) gives the recommended minimum lighting levels for different types of work activity and location. For offices and other workplaces that require perception of detail, the guidelines recommend average illuminance of 200 lux with a minimum illuminance of 100 lux. The US OSHA recommends lighting above 300 lux (30 foot-candles) for office workplaces.

Office environments are generally considered low-risk workplaces, but they still contain health and safety hazards which need to be monitored and controlled. Just the same as any workplace, offices need to have hazards identified and risk assessments carried out in order to implement control measures to reduce the likelihood of a workplace incident occurring.

Office work is visually demanding and requires good lighting for maximum comfort and productivity. "Good" lighting means providing enough illumination so that people can see printed, handwritten or displayed documents clearly but are not blinded by excessively high light levels (a cause of glare).

The most common complaints resulting from poor lighting in the office are:

• difficulty seeing document or screen (too much light or glare, or too little light or shadows),
• eyestrain,
• eye irritation,
• blurred vision,
• dry burning eyes, and
• headaches.

Poor lighting affects not only the ocular system but can also contribute to stiff necks and aches in shoulder area. These problems can occur when people adopt poor or awkward postures when trying to read something under poor lighting conditions.

The computer monitor being a source of light does not require additional illumination from other sources. In fact, the screen itself can cause glare if the brightness and contrast controls are not properly adjusted. Using the monitor and paper documents at the same time introduces additional challenge occurs because paper documents require a higher light level than the monitor. A desk lamp (any type of soft task light) can be used to illuminate documents while avoiding excessive light near the monitor. Glare can also result from an improper match or excessive contrast in light levels between the monitor screen and the paper.

The monitor also acts as a mirror. Reflections of objects, shiny walls, and any light source (specifically windows and overhead lighting) all cause glare resulting in eye discomfort. The quality of the images on the monitor is another important factor. Reading and interpreting blurred, fuzzy, tiny, or otherwise illegible characters for several hours in a day can strain the operators' eyes.

In general, a good visual environment in the office should:

• have sufficient light, coming from the right direction and not cause obscuring shadows,
• provide good (but not excessive) contrast between the task and the background,
• limit glare and extreme contrasts, and
• provide the right type of light.