Fire Alarm System Design

The Regulatory Reform (Fire Safety) Order (RRO) became law on 1 October 2006. Legally, you must comply.

What is the RRO?

Fire authorities no longer issue fire certificates and those previously in force will have no legal status. The Regulatory Reform (Fire Safety) Order (RRO) replaces most fire safety legislation with one new order. It means that any person who has some level of control in premises must take steps to reduce the risk from fire, consider how to contain a fire should one break out and then also make sure people can safely escape if there is a fire.

  • All fire alarm designs should be based on a Fire Risk Assessment
  • All Fire Risk Assessments should be carried out by a competent person
  • Fire Risk Assessments must be reviewed annually

What constitutes a Fire Risk Assessment?

  • Identifying fire hazards such as sources of ignition, fuel or oxygen
  • Identifying all people at risk in and around the premises
  • Evaluating the risk of a fire starting or the risk to
  • people from a fire
  • Removing or reducing fire hazards or risks to people from a fire
  • Protecting people by providing fire precautions
  • Recording any major findings
  • Preparing an emergency plan
  • Informing and instructing any relevant people
  • Providing training for staff and guests
  • Reviewing the fire risk assessment regularly and make changes where necessary
  • Keeping accurate fire risk assessment records.

Where does the order apply?

  • Virtually all premises and nearly every type of building structure and open space.

All fire alarm designs should be based on a Fire Risk Assessment.

BS5839 PART 1 – 2013 & BS5839 PART 6 – 2013

The following guide is intended to be an aid to designers and installers of fire detection systems. It is not to be used as a substitute for BS5839 which should be read in full. In order to help identify the relevant sections, each diagram includes a reference to BS5839 Part 1.

Fire Alarm and Detection systems are categorised in the following ways:

Property Protection Fire Systems

  • P1 AFD installed throughout all areas
  • P2 AFD installed only in defined area

Life Protection Fire Systems

  • L AFD designed to primarily protect Human Life
  • L1 AFD installed throughout all areas
  • L2 AFD installed in defined areas in addition to L3
  • L3 AFD installed in escape routes and rooms opening onto these routes
  • L4 AFD installed in escape routes comprising circulation areas and spaces such as corridors and stairways
  • L5 A non-prescriptive system in which protected area(s) and/or the location of detectors is designed to satisfy a specific fire risk objective (other than thatof L1 to L4)
  • M System designed to be operated manually (of AFD)

*AFD – Automatic Fire Detection


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considerations and handover checklist

Detector typeCeiling Heights (m)
General Limits
Heat detectors EN 54-5:
Class A1
Other classes

Point smoke & CO fire detectors10.5
Aspirating smoke detection systems (category 1)Normal: 10.5
Enhanced: 12.0
Very high: 15.0
Optical beam smoke detectors EN54-1225.0


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