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Why do I need an emergency light test system?

By law, emergency lighting is required within buildings that the public has access to (See What is Emergency Lighting?). It also applies to places of work. 

This is implemented through compliance to standards and codes of practice.  The standards are not just aimed at defining the design of emergency lighting, i.e. how much light and where, but it also covers the installation, commissioning and importantly, the testing of an emergency lighting installation

The codes of practice and testing requirements are outlined in BS 5266 and associate parts as well as EN50172.

How often should an Emergency Lighting system be tested?

The following minimum inspection and tests should be carried out at the intervals recommended below.

Daily Emergency Lighting Inspection

This interval specifically applies to central battery source emergency lighting systems.  In this case a visual inspection of the indicators on the central power supply to identify that the system is operational.  No test of the system operation is required.

Monthly Emergency Lighting Testing

All emergency lighting systems should be tested monthly.  This is a short functional test in accordance with BS EN 50172:2004 / BS 5266-8:2004.

The duration of the test should be sufficient to ensure that the luminaire operates correctly, whilst minimising any damage to the system components, e.g. Lamps, Battery.

It is important to note that the entire system doesn't have to be tested at the same time.  The system can be tested in sections, over a testing schedule, so long as each luminaire is tested each calendar month.

Annual Emergency Lighting Testing

The annual test should be a full rated duration test to ensure that the emergency lights are still working and producing the acceptable level of light at the end of the test.  So for example if a luminaire is rated for a 3 hour duration, then after 3 hours in an emergency situation the light should still be lit.

It is worth noting that this full duration test should be completed at a time of low risk of an emergency situation so that the batteries have sufficient time to recharge.

How is Emergency Lighting Testing Conducted?

Once an Emergency Lighting system has been installed, it should be tested regularly to ensure that it satisfies the requirements of the emergency lighting system and that it operates correctly in an emergency situation.

The testing of the Emergency Lighting system can be carried out either manually or automatically.

Manual Testing of an Emergency Lighting system

A simulated mains failure can be achieved by providing a switch which will isolate all lighting circuits, individual circuits or individual luminaires.

The system is tested by simulating the mains failure by using the supplied switch(es).  Once the circuit(s) or luminaire has been isolated the tester should walk the circuit to check that all emergency lighting luminaires are operating correctly.  After restoring the power to the circuit(s) or luminaire the tester should walk the circuit again to ensure that the emergency lights are recharging.

Disadvantages to manual testing of the emergency lighting system include the cost of an engineer to carry out the testing, and also the potential for disruption to normal activities due to the power to a lighting circuit being isolated.

Automatic Testing of an Emergency Lighting System

An automatic emergency lighting testing system will automatically interrupt the mains power supply to a luminaire or a group of luminaires and detect that the emergency luminaire operates correct, and upon reinstating the mains power supply it will ensure that the battery charges.

The information is collated centrally, allowing the facilities management or building management to collate the testing results.  These test results must still be recorded and collated along with the Commissioning Certificate and Log Book for the system.

BS EN 50172:2004 / BS 5266-8:2004 (Emergency escape lighting systems) specifies the minimum provision and testing of emergency lighting for different premises. Additional information on servicing can be found in BS 5266-1: 2011 (Code of practice for the emergency lighting of premises).

What is the difference between Maintained and Non-Maintained luminaires?

The terms Maintained and Non-Maintained are used to describe the mode of operation for an emergency lighting luminaire, and the decision on which mode of operation to use is determined by the use of the permises.

Maintained Emergency Luminaire

This is a luminaire in which the emergency lamps are lit all the time.  Maintained mode is generally employed in places of assembly such as theatres, cinemas, clubs etc.  The lights are typically dimmed when the premises are occupied, and the emergency escape lighting prevents total darkness.

Non-Maintained Emergency Luminaire

This is a luminaire whose lamps only come on when the power supply to the lighting fails.  Non-Maintained lights are typically found in the work place where artificial lighting is normally deployed whilst the premises are occupied.

The classification of Maintained and Non-Maintained mode of operation can be further broken down or defined with the following classifications.

Combined Emergency Luminaire

This is luminaire which contains 2 or more sets of lamps, at least one of which is powered from the Emergency Lighting supply and the other(s) from the normal mains power supply.  A combined emergency lighting luminaire can be either Maintained or Non-Maintained.

Compound self-contained Emergency Luminaire

This is a luminaire which operates in either Maintained or Non-Maintained mode, and also acts as the emergency lighting power supply to a satellite luminaire.

Satellite Emergency Luminaire

This is a luminaire which operates in either Maintained or Non-Maintained mode, and which derives it's emergency operation supply from an associated compound self contained emergency luminaire.

Are there different types of Emergency Lighting Systems?

One way of classifying the type of Emergency Lighting System is based on how the emergency light has it's power supplied.

The emergency light could contain it's own power supply, in the form of a battery, and this is referred to as Self Contained or Single Point.

Similarly the power could be supplied from a central battery source, where a battery is located somewhere within the premises and the power is supplied to  the emergency light via cabling.

Generally, the decision to use either a central battery or a self-contained system is likely to be cost determined. If an installation has longevity and low maintenance as priorities, then the higher cost of a central battery may be acceptable on a very large project. Typically, luminaire costs and installation costs are a major consideration, particularly on smaller jobs, and it is this criterion which makes the self-contained luminaire the most popular choice.

Self Contained or Single Point


  • The installation is faster and cheaper as additional power cables do not need to be run
  • Standard wiring material can be used, as opposed to fire resistant cables required for central battery source
  • Burn through of the mains cable will automatically satisfy the requirement for the luminaire to be lit
  • Low maintenance costs - periodic testing and general cleaning required
  • Low hardware equipment costs - no requirement for extended wiring, extra ventilation etc
  • Greater system integrity as each luminaire is independant of the others
  • System can easily be extended with additional luminaires
  • No special sub-circuit monitoring is required


  • Environmental conditions may vary across the system, and batteries may be affected by relatively high or low temperatures
  • Battery life is limited to between 2 and 4 years, dependant on the application
  • Testing requires isolation and observation of each luminaire individually

Central Battery Source


  • Maintenance and routing testing is easier, with only one location to consider
  • The life of the battery is between 5 and 25 years, dependant on type
  • Environmentally stable in a protected environment.   The luminaire can operate at relatively high or low temperatures with no affect on the battery
  • Large batteries are cheaper per unit of power and luminaires are usually less expensive


  • High capital equipment costs
  • The cost of installation and wiring is high due to the requirement for fire resistant cable like MICC or Pirelli FP200 to each luminaire
  • Poor system integrity - failure of the battery or wiring circuit at any point can result in failure of a large part of the system
  • Requirement for a "Battery Room" to house batteries and charging circuits, and potential requirement for ventilation systems
  • Localised mains failure in an area of the premises may not trigger the operation of the emergency lighting in that area