Emergency lighting is required to illuminate building areas when things go wrong—for example, when the normal electrical supply is interrupted by a utility outage or by a fire or failure within the building. In most facilities, the largest part of emergency illumination lights the pathways and exits that lead out of the building—the egress paths. Its intent is to facilitate evacuation of the facility, particularly in the event of a fire, and to reduce the tendency of occupants to panic under stress, and in the dark.
Because the performance of emergency lighting is directly related to life safety, code officials are notoriously demanding of strict compliance in its design and installation. Differing interpretations about emergency lighting requirements easily can lead to a costly delay of occupancy. A clear understanding of the code requirements for emergency lighting, and a clear understanding of code officials’ views of any issues that admit interpretation, will go a long way toward avoiding expensive and embarrassing surprises late in construction.
The term “emergency lighting” appears frequently in the codes, but it is nowhere directly defined. For the purposes of this article, emergency lighting refers to lighting equipment that is specifically identified as such in one of the codes, with limited exception. Certain lighting that must illuminate under emergency conditions in health care facilities, but is not technically defined as emergency lighting, is addressed separately.