When the supply to the normal lighting or parts of the normal lighting to occupied premises fails, emergency escape lighting shall be provided:

a) to indicate clearly and unambiguously the escape routes,

b) to provide illumination along such routes to allow safe movement towards and through the exits provided,

c) to ensure that fire alarm call points and fire fighting equipment provided along escape routes can be readily located,

d) to provide sufficient lighting to enable the emergency services to conduct a search and rescue in the event of an incident,

e) to provide lighting for building re-occupation.

The safe movement of persons along escape routes towards and through the exits provided to a place of safety depends upon the illumination and the ability to see hazards, changes of level and direction.

It is recommended that all potential obstructions or hazards on an escape route should be light in colour with contrasting surround. Where the design departs from the above, it will be necessary to compensate for such departures. Escape routes shall be kept clear of unnecessary obstructions at all times and shall not be used as storage areas.

For escape routes up to 2 m in width, the horizontal illuminance on the floor along the centre line of an escaperoute shall be not less than 1 lux and the central band consisting of not less than half of the width of the route shall be illuminated to a minimum of 50% of that value.

NOTE Wider escape routes can be treated as a number or 2 m wide strips or be provided with open area (anti-panic) lighting (see clause 4.2.1 of I.S. EN 1838:1999).

The horizontal illuminance shall be not less than 0,5 lux at the floor level of the empty core area which excludes aborder of 0,5 m of the perimeter of the area (see clause 7.6.8 below, I.S. EN 1838:1999 clause 4.3.1 and,I.S. EN 50172:2004 clause 4.4.).

The emergency lighting specified in this Standard shall provide full luminance within 5 s of the failure of the normal lighting supply.

High risk task area lighting specified in this Standard shall provide the full required luminance permanently or within0,5 s of the failure of the normal lighting supply depending upon application.

The recommended illuminances that are specified as a minimum, i.e. 0,5 lux or 1 lux, shall be regarded as the lowest value acceptable during the rated discharge period and due to the effects of the system ageing (see I.S. EN 1838:1999).

In designing a system allowance shall be made for all of the relevant factors including reduction in voltage, voltage drop in the system wiring, lamp ageing and the accumulation of dirt and dust.

Requirements on the measuring of illuminance of emergency lighting are given in Annex A.

The ratio of the maximum to the minimum illuminance shall be not greater than 40:1 along the centre line of the escape route.

Disability glare shall be kept low by limiting the luminous intensity of the luminaires within the field of view.