FCS-Live provide the installation and maintenance of emergency lighting systems through our trusted supplier. The systems are installed in accordance with British Standard B.S. 5226
UK legislation imposes a duty on persons, including employers and other persons with control of premises, to carry out risk assessments and to take such precautions as to ensure as far as reasonably practicable the safety of the occupants. These measures include the provision of safe means of escape, including emergency routes and exits, together with, where necessary, signs indicating them. Adequate illumination needs to be provided, together with emergency lighting of sufficient intensity in case of failure of the normal lighting.
Illumination for safe movement
The safe movement of people 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.
The stimulus for vision is not the light which falls on objects but the light reflected to the eyes. Different objects are distinguished by contrast of the changes in light reflected to the eyes. A light coloured object on a dark background can be made conspicuous with far less light than a dark coloured object on a dark background. The amount of light falling on an object (illuminance) is affected not merely by the power and position of the lamps used for illumination, but also by reflection from the surroundings. In many interior spaces, a high proportion of the light falling on any surface comes from light from the light sources reflected by other surfaces in the room. Where the walls, floor and ceiling are light in colour, up to 60% of the illuminance at floor level might have been reflected from the walls or ceiling. In a room where the decorative finishes are dark in colour (i.e. have low reflectance), the contribution of reflected light to the illuminance is much smaller. The reflected light might be negligible in, say, a club or restaurant, where the carpets, walls and ceiling have been deliberately kept dark in colour to produce a feeling of intimacy and relaxation. In restricted spaces such as corridors, light coloured decoration throughout is an advantage. Prominent edges to vertical surfaces at changes of direction can assist emergency evacuation. All potential obstructions or hazards on an escape route need to be light in colour with contrasting surround. Such hazards include the nosings of stair treads, barriers and walls at right angles to the direction of movement.
Minimum illuminance and adaptation
Visual acuity varies considerably from one person to another with regard to the amount of light required to perceive an object clearly and the time taken to adapt to changes in the illuminance (visual adaptation). In general, older people, and those with impaired vision, need more light to follow an escape route and have longer visual adaptation times. The maximum period which needs to be allowed to elapse between failure of the normal supply and the switch-on of the emergency lighting depends upon the rate at which a significant number of people might be panicked, which in turn will depend upon factors such as the type of building and the expected people (knowledge, training, physical and mental conditions); and • the time taken to adapt to the new, and normally much lower, illuminance provided by the emergency lighting. The illuminances in this standard have been determined from experience and practical test.
Defined escape routes
To assist escape routes to be used at all times, the horizontal illuminance on the floor along the centre line of an escape route up to 2 m in width should be not less than 1 lx.
Rooms larger than 60 m2 floor area, or those having been risk assessed as needing emergency lighting, should be provided with horizontal illuminance of not less than 0.5 lx at the floor level of the area, excluding a border of 0.5 m around the perimeter.