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Emergency Lighting Information

 

Emergency Lighting is light that is provided automatically when power to the normal lighting fails. It is used to provide sufficient light to allow people to shut down dangerous processes and leave the building safely. Further split down into:

  • Emergency escape lighting (corridors and stairs, bulkhead emergency fittings and exit signage – one lux min with emphasis on changes of level, direction and first-aid/firefighting equipment)
  • Open area lighting/anti-panic lighting (emergency converted versions of ‘normal’ luminaire. Rooms larger than 60 sq m, 0.5 lux min)
  • High risk task area lighting (hazardous areas and machines, nominal 10% of normal light levels)

 

Operation of emergency light fittings:

Maintained – ON all the time, but can normally be switched off without entering emergency mode (will still operate in emergency mode if the power fails), e.g. ‘normal’ emergency converted luminaires.

Non-maintained – ONLY comes on in EM mode in the event of a power failure, e.g. Small LED head style emergency fittings.

Combined/sustained – essentially a standard luminaire with a non-maintained emergency fitting built into it.

 

Power for emergency lighting fittings:

Batteries (NiCd or NiMH, replace after 4 years) – integral or remote (within 1m of light fitting).

Centrally supplied/central battery/static invertor/battery back-up/generator back-up (what voltage do they want? Are they using fire-tough cabling/FP200?).

 

Testing of emergency light fittings:

Manual – the power is manually failed causing the fitting to enter emergency mode, often using a key switch or just at the fuse board.

Self-test – periodically check themselves for proper function and report their status via the indicator LED. Green = good, red = bad.

Networked/central testing/DALI – testing controlled by, and reporting to, a central computer.

 

Testing/inspection/maintenance schedule:

Daily – visual check of indicator LED showing system healthy.

Monthly – function check, nominal 30 seconds of manually initiated power failure and observe system working.

Annually – duration check, typically 3 hrs in emergency mode with visual verification. Building may not have sufficient emergency lighting coverage after a duration test (wait 24 hrs for batteries to recharge), recommend not testing whole building simultaneously.

Automatic testing systems – typically function tests every week, duration tests annually. Fittings test themselves on a random day of a 28-day cycle so as not to cause everything to test at once. The test always takes place at the same time of day, this can be controlled according to the time the system is first energised (and later changed if desired). LED indicator status should be documented as for manual testing – Green solid = healthy, green flashing = test in progress, red = attention required (with further diagnostics given via flash rate).

 

Standards and guidance documents:

Regulatory Reform (Fire Safety) Order 2005.

Building Regulations and Approved Document B.

BS 5266-1:2011 Emergency lighting – Part 1: Code of practice for the emergency escape lighting of premises.

BS EN 1838 (BS 5266-7) – Lighting Applications – Emergency Lighting.

BS EN 50172 (BS 5266-8) – Emergency Escape Lighting Systems.

LG12: Emergency Lighting Design.

ICEL1006 – Emergency Lighting Design Guide.

BS EN 60598-2-22 – Luminaires for emergency lighting.

BS EN 62034 – Automatic test systems for battery powered emergency escape lighting.

BS EN 50171 – Central power supply systems.

BS 7671 – Wiring Regulations.

 

Emergency Lighting Design process:

  • Understand the building layout and purpose of each space
  • Identify emergency escape routes
  • Relate design decisions to the risk assessment that identifies a requirement for emergency lighting
  • Internally illuminated exit signs (almost all of them) can be used from a distance that is 200 times the physical width of their illuminated area (e.g. A 100mm by 300mm sign is appropriate for viewing distances of up to 20 m)
  • Exit signs must be located so as to unambiguously indicate an escape route, normally mounted at least 2 m above the floor.
  • Exit signs come in a range of styles (see Fig 1 below), they should not be mixed within a single area/building wing.
  • Always put emergency lighting in Wcs for the disabled
  • Generally, always put emergency lighting in Wcs with stalls in
  • Emergency lighting is normally required at the escape route exit point of a building
  • Normally, 1 lux minimum is required all the way along a corridor
  • Normally, 0.5 lux minimum is required in open areas greater than 60 sq m (except in a 0.5m wall zone)

 

Fig 1.

different-exit-sign-images

 

 

 

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