Glossary of Emergency Lighting


A guide to terminology used in the emergency lighting industry.

Anti-panic (Open) area

An open area to provide assembly or safety in an emergency, required to be illuminated by emergency lighting. Usually an external area.


An electrical internal component within the luminaire to control the operation of the light source from the AC / DC supply. Ranging from 12 to 140 volts.

Ballast Lumen Factor (BLF)

Is a measure of the light output of the lamp when the ballast is operated at its designed voltage. Usually ballasts operate at 100%, meaning they will power the lamp at 100% of its capability. Some ballasts operate at around 80% to ensure that the lamp lasts longer and has a lower operating temperature.


Storage cells providing the power during mains failure.

Battery – Sealed

A battery where the electrolyte cannot be replaced.

Battery – Vented

A battery where the electrolyte is required to be replaced.

Battery Capacity

The capability of the battery under discharge situation measured in Ampere-hours (Ah, over one hour).


The British standard for emergency lighting, split into many parts and updated over time. Now combined into the European standard BS EN 1838.

BS EN 60598-2-22:1999

The standard to which the luminaires must meet.



A unit of luminous intensity wikipedia Definition

Central Battery System

A central unit that houses the batteries and control gear for a number of emergency lighting luminaires.

Charge Indicator

A green LED indicator to show that the integral battery is connected and charging.

Combined Emergency Luminaire (Sustained)

A luminaire that has two or more lamps, one of which is powerd from the battery backup under mains failure, the other supplied direct from the mains supply.

Conversion Kit

A kit of parts used to modify most types of mains lighting into main and emergency lighting.


Directional Beam

The light emmited from the luminaire is focused to provide light into a paticular area.


Emergency Exit Route

The way out of the building, not necessarily in everyday use. Needs to be clearly marked with appropiate signs.

Emergency Lighting

The lighting that is for use when there is a mains power or circuit failure.

Escape Route Lighting

Lighting installed along the route of escape so that the ocupants can safely evacuate from a building. Changes in direction should be clearly marked and special areas illuminated.

Externally illuminated Sign

A life safety sign that is illuminated from an external source within 2 meters.


F Mark

Mark to indicate that the luminaire is suitable for mounting to flammable surfaces.

Final Exit

The end point of an escape route at which point the person past this should not be any danger from the reason of evacuation.

Flood Beam

The light emmited from the luminaire is generalised to cover as much surface area as possible in the area.


High Output

A luminaire that gives a greater amount of light either directional or flood.

High Risk Area Emergency Lighting

Emergency Lighting in areas of high physical risk to assist in the safe shut down of the facility. Emergency lighting should provide 10% of normal illumination.

Hot Wire 850°C Test (Housing Test)

All emergency lighting luminaires must pass this test to ensure that the material does not burn at the given temperature. All plastics must meet this test or the luminaire manufactured from glass or steel.


Illuminance (Lux)

Measured in lumens per m2 (lm/m2) this is the luminous flux density at a given surface.

Ingress Protection (IP) Rating

Classifies the degrees of protection provided against the intrusion of solid objects and water. Format is “IP” followed by two numbers and an optional letter. wikipedia Definition

Internally Illuminated Sign

A sign that when required is illuminated from its own internal source.



A light bulb typically fluorescent or tungsten.


A Light-emitting diode. Wikipedia Definition


A measure of the power of light perceived by the human eye. Used to describe the quantity of light emitted by a source.


An electrical device that typically contains a light source and housing that is wired to a power source and fixed to a ceiling or wall. Wikipedia Definition

Luminous Flux (Lm)

Is the measure of the perceived light measured in lumens emitted in all directions.

Luminous Intensity (Cd)

The power of the light source to emit light in a given direction measured in candela.

Lux (lx)

Is the unit of illuminance. One Lux is equal to one lumen per m2.


Maintained Emergency Light

A luminaire that contains one or more light sources that are permanently illuminated during normal and emergency situations. See also Switchable Maintained Emergency Light.

Mounting Height

The direct vertical distance between the luminaire and the floor.


Non-Maintained Emergency Light

A Luminaire that containes one or more light sources and only illuminates during a mains or circuit failure situation.


Rated duration

The specified duration of light output from the luminaire operating from it’s battery supply. Typically 1 to 3 hours on a fully charged battery.

Rated Load

The maximum load that can be placed on a system.


The method of mounting the luminaire into a wall or ceiling void so that the luminaire is flush with the surface.

Re-charge time

The amount of time to fully charge the batteries to obtain the rated duration in emergency mode.


Self Contained Emergency Light

A luminaire that houses all the electrical components. Typically a light source, control gear and battery backup.

Self Test Emergency Light

A luminaire that automatically conducts tests to ensure safe and continued operation and function indicating faults by audio or visually displaying warning lights.

Surface Mount

The method of fixing the luminaire to the wall or ceiling so that it sits on top of the surface.

Sustained Emergency Light

See Combined Emergency Luminaire

Switchable Maintained Emergency Light

A luminaire that can act as the mains room light and as an emergency light. It can be turned off/on via the room light switch and operate in the event of a power / circuit failure.


Uninterruptible Power Supply (UPS)

A device that provides emergency power to a load when the main source fails. Typically a luminaire is connected to the mains through a UPS, the UPS provides mains output to the luminaire when it detects a failure to the incoming mains.