Lighting has a profound impact on people. It effects their physical, psychological and physiological health and overall performance in the workplace. Unfortunately, we fail to give lighting adequate consideration when planning for the office.
The physical effect that lighting has on employees is quite obvious. Inappropriate lighting can lead to eyestrain. Studies have shown that poorly lit environments are less productive due to time lost with vision problems and discomfort.
The psychological and physiological effects of lighting may not be as obvious as the physical effects, yet they are just as strong. Light sends a visual message which effects mood and motivation levels. Our circadian rhythms for sleeping and walking are also influenced by light.
There should be a “layering” of light to create optimum comfort and safety in the workplace. There are three key components that are accentual to quality lighting. They are ambient, task and accent lighting.
Ambient Lighting provides the overall illumination in a work environment. There are two types of ambient lighting; direct ambient lighting and indirect ambient lighting.
Direct ambient lighting distributes light directly downward. Lights with parabolic louvers help reduce some glare, but their effectiveness depends on where you are positioned relative to the light source. These lights often create shadows and computer screen glare. They can also contribute to an overall sense of dimness in a space.
Indirect ambient lighting distributes light upward and reflects off the ceiling. When applied, it can reduce direct and reflected glare to an absolute minimum. Its soft, diffused illumination has proven to be more comfortable for computer users than direct lighting sources. Indirect lighting can create an overall sense of brightness.
Task lighting supplements ambient lighting by filling in shadows and provides additional light needed for focused work that requires higher light levels. Task lighting is playing an increasingly important roll as ambient light levels are reduced due to the prominence of computer usage and the ecological importance of saving energy.
Accent lighting completes the lighting environment and is a powerful element in a lighting system. It can be used practically to provide fill light to finish and balance the ambient light. It can be used artfully to highlight unique objects or reinforce aesthetics. It can draw people through a space or provide visual relief in areas without daylight. Skillfully applied, accent lighting can transform the perception of space.
The Illuminating Engineering Society of North America (IESNA) has set three key criteria for lighting designers to use as the basis for creating comfortably lit work environments without glare or extreme contrast. The three key criteria are horizontal illuminance, veritcal illuminance and ceiling luminance uniformity.
Horizontal illuminance is the amount of light on horizontal surfaces, such as worksurfaces. Light must be sufficient and uniform enough to allow you to read printed text, review drawings and perform other tasks. Horizontal illuminace is effectively achieved by combining ambient and task light.
Vertical illuminance is the amount of light on vertical surfaces, such as office walls, cubicle walls, computer screens, and paper placed on document holders. Lower and more uniform levels within the immediate work area are generally recommended because high vertical illuminances can cause veiling reflections on computer screens. Higher levels at strategic locations within the architectural environment are often recommended to contribute to a brighter, more pleasant workplace.
Ceiling luminance uniformity is the degree to which the light across the ceiling seems even. The more even it appears, the less chance you’ll see it as reflected glare on your computer screen.
Examine the role lighting can play in your environment. Carefully consider your lighting decisions. Anticipate the effect these decisions will have on your employees, your customers and your business. Additionally, be certain that the lighting plan integrates with the other systems at work in your building and that it supports the different kinds of work people do in the space.