Light is a force that has a powerful impact on the human body. Studies have shown that dedicated applications of lighting can have an effect on all aspects of a worker’s experience, including reduction in eyestrain, illness, accidents, and even absenteeism. Here are 5 key considerations when evaluating and optimizing the lighting in your facility.
1. Light Intensity
Lighting in the average workplace ranges from 50 to 500 lux (a measurement of illumination equal to the intensity of one candle). Research has shown that proper use of lighting can lessen the loss of alertness, production errors, and accidents, especially among nightshift workers and those on rotating shifts.
A 60-watt incandescent bulb in a 10-foot-high ceiling will produce only about 100 lux at eye level. Studies show that carefully timed exposure to bright light (over 1,000 lux) decreases fatigue and increases alertness.
You may want to have your facilities manager assess the wattage of lights over workstations, check for burned-out bulbs, and make sure that lighting fixtures are dusted and cleaned periodically.
Supplemental lighting with lamps, rather than more overhead lighting, can be added at workstations as needed to adequately illuminate tasks.
2. Interior Colors
Interior colors, especially in production areas, should be of medium value. Therefore, dark-colored carpeting and flooring, window treatments, walls, and cubicles may not be the best choice. Dark colors also absorb light, thus requiring the use of more wattage—and electricity—to illuminate an area. On the other hand, light or bright colors can contribute to glare and eyestrain.
3. Surface Reflectants
Workers’ eyes move from brightly lighted surfaces to dark walls and floors or shadows. Their eyes must work hard to make this transition, which causes eye fatigue.
You will want to make sure that lighting is diffused through baffles or bounced off surfaces in such a way that serious shadows and glare are avoided. Use of matte finishes, rather than glossy or polished surfaces, is also recommended for work areas.
4. Types of Lighting
Incandescent. This type of lighting was invented by Thomas Edison and has been used for over 100 years. Modern technology has reduced glare through the development of soft white, reflector, linestra, and other types of bulbs.
Halogen. This type of bulb is often used in task lighting and track lighting because it saves energy.
Fluorescent. New energy-saving bulbs can be used as direct replacements for incandescent bulbs and give more realistic color quality, and can save as much as 75 percent in energy costs.
New technology also allows electronic ballasts to operate at a high frequency that eliminates flickering, which can produce headaches, nausea, and fatigue.
The middle bulbs of 4-bulb fluorescent light fixtures can be removed to reduce the brightness of the light to levels more compatible with tasks if diffusers or alternative light sources are not available.
Full-spectrum lighting. These new bulbs simulate the full-spectrum light of natural sunshine. Not only do they reduce eyestrain, but they have the added dimension of improving mood, especially during the shorter days of winter or for night workers.
Full-spectrum lighting has been used in Russian factories to reduce absenteeism due to colds and flu. Studies show that worksites with full-spectrum lighting had one-half the absenteeism for illness than those that did not. Another study done in Canada had similar results.
Sunlight. It is obvious, but the effective use of natural sunlight to reduce the use of artificial lighting and eliminating overlighted or underlighted areas should be a priority.
Furniture and equipment should be placed so that it does not block light from windows. Workstations and computers should be placed so light from windows is at right angles with the computer screen and machine gauges and controls.
Take a look at windows. Do they need to be cleaned inside and out? Should landscaping near windows be cut back to allow more light in? Are those blinds and curtains necessary or would a window film work more effectively at reducing glare?
Note: Vertical blinds work best for East/West facing windows and horizontal blinds for North/South facing windows.
If you want to install light sensor equipment, you must measure current light levels, determine how you want your system to be programmed, and test its functions.
5. Layered Lighting
If possible for your facility, it is recommended that you install three layers of light over workstations:
- An ambient or general layer achieved by fluorescent or indirect lighting.
- A task layer accomplished with low-wattage lamps inside or above workstations. Task lighting should have a three-way switch or dimmer to accommodate individual workers’ needs.
- Fill lighting, using compact “wall washers,” or recessed lighting can lighten up perimeter surfaces that either don’t have window or are used at night. Using fill lighting directed toward walls eliminates a “cave effect” in otherwise unlighted surfaces.