Why Emergency Lighting?
An Emergency Lighting System is essential to show clearly the escape routes from a building and to allow safe movement (to exits) moving at walking pace without stumbling, to help prevent panic in an emergency and during evacuation, to show the location of and identify fire equipment, for example fire extinguishers and manual call points and to permit safety operations such as administering first aid.
NOTE: Although not compulsory, floor mounted and way guidance systems would be in addition to overhead lighting, there is no dispute that emergency lighting is required to help people escape safely and quickly from a building. Using signs to show the escape route(s) is an essential part of emergency lighting, because those signs must be visible during a mains failure. In addition to providing for escape, emergency lighting should illuminate any fire equipment, such as portable extinguishers and manual call points, either on the escape route or elsewhere, and permit safety operations such as first aid and firefighting.
Emergency Lighting Requirements
In the UK, the Fire Safety legislation requires emergency lighting to be provided in the following premises:
- Offices and shops – Premises that provide care
- Community halls – Pubs, clubs and restaurants
- Schools – Tents and marquees
- Hotels and hostels – Factories and warehouses
- Common areas in houses in multiple occupation
If artificial lighting is installed, emergency lighting is likely to be required:
- on escape routes
- in open areas larger than 60m2 (or smaller if risk assessed)
- to show exit signs
1 hour minimum duration (autonomy) for emergency lighting:
- must fully recharge within 24 hours before reoccupation
- premises must be evacuated immediately
3 hour duration of emergency lighting required for:
- sleeping risk (hotels)
- licensed premises and places of entertainment
- premises requiring early reoccupation (schools, hospitals)
Because of the two types being allowed, in the UK, 3 hour duration emergency lighting is almost exclusively used, to avoid confusion and multiple product types. An advantage of using 3 hour duration where 1 hour is the minimum requirement is that if the mains fails for just 1 hour, there is still 2 hours duration remaining in the batteries, allowing an immediate reoccupation of the premises. If 1 hour duration had been used, the batteries would have no remaining capacity and would take up to 24 hours to recharge, delaying the reoccupation of the premises.
Emergency Lighting Classifications
- Self Contained – A luminaire or sign providing Maintained or Non-Maintained emergency lighting, in which all the elements such as battery, the lamp and the control unit are contained within the housing or within 1 metre of the housing.
- Centrally Supplied – A system in which the batteries for a number of emergency luminaires are housed in one location
Mode of Operation
- Non-maintained (NM) – luminaire only operates when the normal supply to the mains lighting fails. It does not operate with healthy mains.
- Maintained (M) – luminaire also operates when then normal supply to the mains lighting fails, but connections can be arranged so it can be switched on and off in the normal way when there mains is healthy.
- Combined (C-NM, or C-M) – luminaire has more than one lamp, but one is dedicated to emergency use and operates when the mains fails. Historically combined luminaires were called sustained.
- Compound – self-contained emergency luminaire: a luminaire providing maintained or non-maintained emergency lighting and also the emergency power supply to a satellite luminaire.
- Satellite – a luminaire for maintained or non-maintained operation and which derives its emergency operation supply from an associated compound self-contained emergency luminaire.
Remember, the correct design of emergency lighting systems is essential in saving lives.