In most areas, lighting requirements determine the illumination levels for indoor and outdoor spaces.
For safety and efficiency, building codes and ordinances require set light levels for a number of situations and locations. If you are designing the lighting for a public facility or for any place of business, either open to the public or hosting workers, you’ll need to comply with the pertinent codes and ordinances in your area. The Life Safety Code, Universal Building Code and International Building Code all set guidelines for lighting along exit paths. Regarding outdoor lighting, codes and ordinances vary widely at a local basis. The Occupational Safety and Health Administration regulates general workplace lighting.
Exit Lighting Requirements
According to both the Life Safety Code and the International Building Code, the exit route of any building open to the public must be illuminated during all times to average at least 1-footcandle, measured at the floor. A footcandle represents the light cast by one lumen, where it equally distributes over one-square-foot. While the average illumination must be 1-footcandle, the lowest intensity at any single point must be at least 0.1-footcandles. The Life Safety Code further specifies that in times of emergency, this lighting remains powered for up to 1-1/2 hours following the failure of normal lighting. At the end of the 1-1/2 hours, the lighting must have an intensity averaging no less than 0.6-footcandles, with a minimum of .06 footcandles at any given point.
Outdoor Lighting Requirements
Lighting ordinances and regulations vary widely by region and municipality. Whereas some requirements may demand that lighting meet minimum intensity levels, other regulations may impose maximum light levels to decrease light pollution. The International Dark Sky Association, a body devoted to combating light pollution, provides a partial directory of national, state and local ordinances related to outdoor lighting on its website. The ordinances of Flagstaff, Arizona and Borrego Springs, California earned designations as International Dark Sky communities, thanks to the highly restrictive policies on excessive outdoor lighting, requiring that outdoor lights above certain intensities have caps to shield any upward-directed light rays.
Workplace Lighting Requirements
The Occupational Safety and Health Administration, or OSHA, establishes guidelines for lighting levels in workplaces. For specific information about your area, consult with your state-level OSHA authorities. In general, OSHA’s illumination requirements apply to emergency lighting, as covered by various building and safety codes, as well as light levels for specific kinds of workplaces. First aid stations, infirmaries and offices must have light levels of at least 30-footcandles. General construction plants or workshops, as well as all bathroom facilities, must have an illumination of at least 10-footcandles. Corridors, warehouses, hallways, exitways, tunnels and underground shafts must have a light level of 5 footcandles or more.