Compliance codes of Emergency lights

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.[3] As there are strict requirements to provide an average of one foot candle of light along the path of egress, emergency lighting should be selected carefully to ensure codes are met. In recent years, emergency lighting has made less use of the traditional two-head unit – with manufacturers stretching the concept of emergency lighting to accommodate and integrate emergency lighting into the architecture. 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. Self-contained emergency lighting fittings may operate in “Maintained” mode (illuminated all the time or controlled by a switch) or “Non-Maintained” mode (illuminated only when the normal supply fails). Some emergency lighting manufacturers offer dimming solutions for common area emergency lighting to allow energy savings for building owners when unoccupied using embedded sensors.[4] Another popular method for lighting designers, architects and contractors are battery backup ballasts that install within or adjacent to existing lighting fixtures. 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 for remote mounted emergency lighting generally mandate that wiring from the central power source to emergency luminaires be kept segregated from other wiring, and constructed in fire resistant cabling and wiring systems. 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. The most recent codes of practice require the designer to allow for both failure of the supply to the building and the failure of an individual lighting circuit. BS5266 requires that when Non Maintained fittings are used, they must be supplied from the same final circuit as the main lighting circuit in the area.