Emergency light

In the United States, emergency lights are standard in new commercial and high occupancy residential buildings, such as college dormitories, apartments, and hotels.

Simple transistor or relay technology was used to switch on the lights and battery supply in the event of a power failure.

In the United States, modern emergency lighting is installed in virtually every commercial and high occupancy residential building.

The emergency lighting heads have usually been either incandescent PAR 36 sealed beams or wedge base lamps, but LED illumination is increasingly common.

New York City requires emergency lights to carry a Calendar Number signifying approval for local installation,[1] Chicago requires emergency lighting to have a metal face plate,[2] and Los Angeles requires additional exit signs be installed within 18 inches (460 mm) of the floor around doors to mark exits during a fire, as smoke rises and tends to block out higher installed units.

An emergency lighting installation may be either a central standby source such as a bank of lead acid batteries and control gear/chargers supplying slave fittings throughout the building, or may be constructed using self-contained emergency fittings which incorporate the lamp, battery, charger and control equipment.

Upon sensing power loss, the ballasts switch into emergency mode turning the existing lighting into emergency lighting in order to meet both the NFPA's Life Safety Code and the National Electric Code without the need of wiring separate circuits or external wall mounts.

Codes of practice lay down minimum illumination levels in escape routes and open areas.

Codes of practice also lay down requirements governing siting of emergency lighting fittings, for example the UK code of practice, BS5266, specifies that a fitting must be within 2 metres (6 ft 7 in) horizontal distance of a fire alarm call point or location for fire fighting appliances.

According to British fire safety law, an entire assessment of the system must be conducted yearly and “flick-tested” at least once a month.