In seeking to escape from a building the occupants will find it easier if the escape routes are illuminated. Specifically dedicated escape lighting is not necessary within dwellings as it is assumed the occupants will have a degree of familiarity with the layout, and escape routes only begin at the door to the dwelling. However in buildings containing flats and maisonettes, the common escape routes should be illuminated to assist the occupants of the building to make their way to a place of safety.
Every part of an escape route should have artificial lighting supplied by a protected circuit that provides a level of illumination not less than that recommended for emergency lighting. Where artificial lighting serves a protected zone, it should be via a protected circuit separate from that supplying any other part of the escape route.
Artificial lighting supplied by a protected circuit need not be provided if a system of emergency lighting is installed.
A protected circuit is a circuit originating at the main incoming switch or distribution board, the conductors of which are protected against fire. Regardless of what system is employed, escape routes should be capable of being illuminated when the building is in use. In conversions for example, it may be easier to install self-contained emergency luminaries than to install a protected circuit to the existing lighting system.
Emergency lighting is lighting designed to come into, or remain in, operation automatically in the event of a local and general power failure.
The emergency lighting should be installed in accordance with BS 5266: Part 1: 2005 as read in association with BS 5266: Part 7: 1999 (BS EN: 1838: 1999).
In order to assist the evacuation of occupants in high rise domestic buildings, every protected lobby, protected zone (including escape stairs) and any other associated escape route should be provided with emergency lighting designed and installed in accordance with BS 5266: Part 1: 2005 as read in association with BS 5266: Part 7: 1999 (BS EN: 1838: 1999).