Section 1: Fire detection and alarm systems

General provisions

1.1 All buildings should have arrangements for detecting fire and raising the alarm. In most buildings, fires are detected by people, either by sight or smell, and therefore often nothing more is needed.

1.2 In some small buildings/premises, the means of raising the alarm may be simple (for example, a shouted warning). In assessing appropriate solutions, warnings need to be heard and understood throughout the premises.

Fire detection and alarm systems

1.3 Other than for some small buildings/premises, an electrically operated fire alarm system should be provided. In some situations, the alarm should be operated by a fire detection system. The detailed specification should be compatible with the fire strategy for the building.

NOTE: The term ‘fire alarm system’ describes the combination of components for giving an audible and/or other perceptible warning of fire.

NOTE: In this document, the term ‘fire detection system’ describes any type of automatic sensor network and associated control and indicating equipment. Sensors may be sensitive to smoke, heat, gaseous combustion products or radiation. Automatic sprinkler systems can also be used to operate a fire alarm system.

1.4 In ‘residential (institutional)’ and ‘residential (other)’ occupancies (purpose groups 2(a) and 2(b)), automatic fire detection and alarms should be provided.

1.5 Automatic fire detection and alarm systems should be provided in non-residential occupancies where a fire could break out in an unoccupied part of the premises (e.g. a storage area or a part of the building that is not visited on a regular basis) and prejudice the means of escape from occupied part(s) of the premises.

1.6 Automatic fire detection will also be necessary where fire protection systems, such as pressure differential systems or door releases, need to operate automatically.

1.7 Every building design should be assessed individually. General guidance on the category of fire detection system that may need to be provided within a building can be found in Table A1 of BS 5839-1.

1.8 Where an electrically operated fire detection and alarm system is provided, it should comply with BS 5839-1.

1.9 BS 5839-1 specifies three categories of system.

a. Category L – for the protection of life.

b. Category M – manual fire detection and alarm systems.

c. Category P – for property protection.

Category L systems are divided into the following.

L1 – systems installed throughout the protected building.

L2 – systems installed only in defined parts of the protected building (a category L2 system will normally include the coverage required of a category L3 system).

L3 – systems designed to warn of fire at an early enough stage to enable all occupants, other than possibly those in the room where the fire started, to escape safely before the escape routes become impassable because of fire, smoke or toxic gases.

L4 – systems installed within those parts of the escape routes that comprise circulation areas and circulation spaces, such as corridors and stairs.

L5 – systems in which the protected area(s) and/or the location of detectors are designed to satisfy a specific fire safety objective (other than that of a category L1, L2, L3 or L4 system).

Type P systems are divided into the following.

P1 – systems installed throughout the protected building.

P2 – systems installed only in defined parts of the protected building.

1.10 Electrical alarm system call points should comply with either of the following.

a. BS 5839-2.

b. BS EN 54-11 Type A (direct operation).

Call points should be installed in accordance with BS 5839-1.

Type B (indirect operation) call points of BS EN 54-11 should only be used with the approval of the building control body.

1.11 A voice alarm system complying with BS 5839-8, and giving a fire warning different from other signals in general use, may be considered if either of the following applies.

a. People might not respond quickly to a fire warning.

b. People are unfamiliar with the fire warning arrangements.

1.12 In premises where lots of members of the public are present, an initial general alarm may be undesirable. Any fire alarm system that first alerts staff should comply with BS 5839-1.

1.13 Where the escape strategy is based on simultaneous evacuation, actuation of the fire alarm system should give warning from all fire alarm sounders. Where phased evacuation is planned, a staged alarm system is appropriate. See paragraph 3.21.

1.14 BS 9999 provides guidance for fire detection and alarm systems in buildings containing atria.

Warnings for people with impaired hearing

1.15 Clause 18 of BS 5839-1 gives detailed guidance on the design and selection of fire alarm warnings for people with impaired hearing. In buildings or part of a building where people may be in relative isolation, a visual and audible fire alarm may be the most appropriate solution. In buildings where the population is managed, a vibrating personal paging system may be more appropriate.

Design and installation of systems

1.16 Fire detection and alarm systems must be properly designed, installed and maintained. A design, installation and commissioning certificate should be provided for fire detection and alarm systems. Third party certification schemes for fire protection products and related services are an effective means of providing assurances of quality, reliability and safety.

Interface between fire detection and alarm systems and other systems

1.17 Fire detection and alarm systems sometimes trigger other systems. The interface between systems must be reliable. Particular care should be taken if the interface is facilitated via another system. Where any part of BS 7273 applies to the triggering of other systems, the recommendations of that part of BS 7273 should be followed.