What are the different types of Emergency Lighting Systems?

chase-fire-logoOne way of classifying the type of Emergency Lighting System is based on how the emergency light has its power supplied. The emergency light could contain its 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

Advantages:

  • 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 independent of the others
  • System can easily be extended with additional luminaires
  • No special sub-circuit monitoring is required

Disadvantages:

  • 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, dependent on the application
  • Testing requires isolation and observation of each luminaire individually

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Central Battery Source

Advantages:

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

Disadvantages:

  • 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
  • Localized mains failure in an area of the premises may not trigger the operation of the emergency lighting in that area