General lighting is the broad distribution of lighting in a space. General lighting selection should be driven by efficiency, lamp life, color quality of the light, and its intended use with a combination of direct (downward) and indirect (upward) light sources. The ceiling layout impacts the effectiveness of a general lighting scheme. Use a non-uniform lighting layout to give more visual stimulation and appeal, supplemented with task lighting providing high illumination on the worker’s task. General lighting system components are lamps, fixtures (reflectors, diffusers, and lens), ballasts, and controls. Using fluorescent, High-intensity Discharge (HID), and/or Light emitting Diode (LED) lamps, coupled with effective fixtures and appropriate controls, can reduce energy consumption. Consider the ceiling, floor, and wall surface reflectance values to maximize light levels. Search SFTool for more on lighting.
Economic Lighting Upgrade
Choosing a more efficient lamp and appropriate control reduces the amount of waste heat generated. The reduction in heat allows the cooling system to run less often.
LED lamps use even less energy. If replacing your cooling system, you may be able to purchase a smaller, less expensive chiller and air distribution system.
Electronic ballasts are more energy efficient than older, magnetic ballasts.
Fixtures can be selected to reduce glare and diffuse light, limiting direct brightness on desk tasks and computer screens.
Electronic ballasts avoid flickering that can bother some building occupants. These newer ballasts are also made without polychlorinated biphenyls (PCBs).
Lower general lighting levels, combined with task lighting, can adequately illuminate writing and reading tasks while limiting excessive brightness on computer screens. (Note: glare is much less of a problem for flat panels than older computer models)
Provide some lighting on walls to avoid shadows that can make a space appear dreary or enclosed.
Unevenly distributed light on task surfaces can create contrast problems, making it difficult to see work tasks and can cause eyestrain.
Be aware of possible veiling reflection situations (when light strikes a reading task and produces overwhelming shiny spots, obscuring vision) when placing overhead general lighting fixtures.