The purpose of emergency lighting is to ensure the lighting is provided promptly, automatically and for a suitable time when the normal power supply to the lighting fails to ensure that people within the building can evacuate safely in the event of an emergency. The legal requirement is that non-domestic buildings must be safe at all times, even if mains power failure occurs. Therefore, nearly all such buildings must have emergency lighting fitted.
Emergency lights are permanently mounted, battery operated lights, which are tied into the building’s power grid. They draw power from the grid to maintain the battery fully charged. In the event of a power loss, the light automatically turns on, providing enough light for people to leave the facility.