Whether in industrial or office settings, proper lighting makes all work tasks easier. People receive about 85 percent of their information through their sense of sight. Appropriate lighting, without glare or shadows, can reduce eye fatigue and headaches. It highlights moving machinery and other safety hazards. It also reduces the chance of accidents and injuries from "momentary blindness" while the eyes adjust to brighter or darker surroundings.
The ability to "see" at work depends not only on lighting but also on:
Please also see:
Remember, not enough light can also be a problem so even in workplaces where daylight is available, it is essential to have a good electric lighting system.
Electric Lighting: The amount of light, the colour of the light itself and the colour that objects appear vary with the type of electric lighting. The lighting must match the workplace and the task. The following are common types of bulbs.
|Type||Common Application||Efficiency||Colour Rendering**|
|Fluorescent||offices||good||fair to good|
|Mercury||factories, offices||fair||fair to moderate|
|Low pressure sodium||roadway||good||poor|
|High pressure sodium||factories, commercial||good||fair to good|
|Metal Halide||factories, commercial||good||good|
* Bulbs are often referred to as lamps in many technical publications.
** Colour rendering is the effect of light on the colour of objects.
There are three basic types of lighting:
General lighting provides fairly uniform lighting. An example would be ceiling fixtures that light up large areas.
Localized-general lighting uses overhead fixtures in addition to ceiling fixtures to increase lighting levels for particular tasks.
Local (or task) lighting increases light levels over the work and immediate surroundings. Local lighting often allows the user to adjust and control lighting and provides flexibility for each user.
The complete lighting unit (also called the light fixture) controls and distributes the light. (Light fixtures are often referred to as "luminaires" in technical publications.)
Various types of light fixtures are designed to distribute light in different ways. These fixtures are known as:
No single type of light fixture is appropriate in every situation. The amount and quality of lighting required for a particular workstation or task will determine which light fixture is most suitable.
Direct light fixtures project 90 to 100 percent of their light downward toward the work area. Direct lighting tends to create shadows.
Direct-indirect light fixtures distribute light equally upward and downward. They reflect light off the ceiling and other room surfaces. Little light is emitted horizontally meaning direct glare is often reduced. They are usually used in "clean" manufacturing areas.
Indirect light fixtures distribute 90 to 100 percent of the light upward. The ceiling and upper walls must be clean and highly reflective to allow the light to reach the work area. They provide the most even illumination of all the types of fixtures and the least direct glare. Indirect light fixtures are usually used in offices.
Shielded light fixtures use diffusers, lenses and louvers to cover bulbs from direct view; therefore, helping to prevent glare and distribute light.
Yes. The "colour" of an object actually depends upon the colour composition of the light itself as well as the colours of the light that the object reflects and absorbs.
Natural sunlight is made up of all the colours of the rainbow (spectrum) red, orange, yellow, green, blue, indigo and violet. Most electric lights do not "make" of all these colours even though the lights appear to be emitting "white" or "normal" light. In fact, different lights give different colour rendering characteristics. As a result, the true colour of an object can only be determined when viewed under sunlight or under lighting, such as full spectrum lighting, that has the same spectral composition as sunlight.
For most work situations, colour rendering is not an issue. However, full spectrum lighting may be needed when colour judgement is important; for example, in a fabric manufacturing or sewing environment.
Document last updated on January 27, 2003