The purpose of a fire alarm

The purpose of a fire alarm system, whether it be wired or a wireless fire alarm system, is to support the fire safety strategy for the building. It is, in particular, important that system design suitably supports the required fire evacuation procedures, rather than those
procedures being designed around a pre-determined system design. A fire risk assessment of how the building is to be used is advisable at this stage.

To a large extent, the design of the fire alarm system will depend on the actions and procedures required after the fire alarm has been given. Particular care is necessary in the case of a fire system that is to be capable of giving a two (or more) stage alarm.
If a premises contains fire systems associated with hazards other than fire, the various hazard alarms need to be properly co-ordinated and be distinct from each other. In these types of buildings, the relative priorities need to be carefully assessed, and the system arranged so that a higher priority alarm cannot be prevented
or obscured by one of a lower priority. Although, in general, fire will have the highest priority, there are buildings in which other hazards can have higher priorities than fire.

The system requirements, including those imposed by the evacuation procedures, the configuration of the building, and the use to which the building is put, need to be ascertained as accurately as possible by
consultation between the user or purchaser and other interested parties, such as the fire risk assessment person, enforcing authority or fire insurer.
It is advisable that there also be relevant consultation between the user or purchaser and the fire system designer. In a small, simple building, the extent to which such consultation is necessary may be minimal;
the user or purchaser might have little knowledge of fire safety principles, and system design can involve
little more than determination of the appropriate locations of manual call points and fire alarm devices. In
complex premises, there will be a need for extensive consultation between the user or purchaser, the enforcing
authority, the system designer and, possibly, specialist consultants.