Fire Alarm Zones

In many buildings, the evacuation strategy will be very simple; on operation of any fire alarm manual call point, or detection of fire by  automatic fire detection, fire alarm sounders will operate throughout the building to indicate the need for evacuation of the entire building.
In larger, more complex buildings, the fire “Evacuate” signal may, in the first instance, be restricted in extent (e.g. to a single floor, a limited number of floors or a limited area of the building). In other areas, an fire “Alert” signal may be given to warn occupants of the fire alarm signal, without any requirement for those occupants to
evacuate.

In order to support such arrangements, it is necessary for the building to be divided into a number of individual alarm zones and for the installation of an addressable fire alarm system.  The operating state of fire alarm sounders in any alarm zone is independent of the operating state of fire alarm sounders in all other alarm zones. The fire alarm sounders control by the addressable fire alarm are thus grouped, so that, at any point in time, all alarm sounders within any given alarm
zone are in the same state (i.e. silent, giving an “Alert” signal or giving an “Evacuate” signal).
The need for sub-division of a building into discrete alarm zones may arise for a number of reasons,
including:
1.the use of phased evacuation.
2. to avoid unnecessary disruption when false alarms occur.
Any other circumstances in which a two stage alarm arrangement applies.
Since it will be the case that, when occupants of one alarm zone are required to evacuate, occupants of one or more alarm zones above, below or adjacent to that zone will be expected to remain in the building, every alarm zone needs to be separated from all other alarm zones by fire resisting construction. (In some complex
public buildings, such as shopping centres, alarm zones are designed to coincide with smoke control zones,
which are separated from each other by smoke curtains, rather than fire resisting construction. However, in this case, the audible signal is normally given by a voice message, rather than audible fire alarm devices.)
As the sub-division of a building into alarm zones implies that, in the early stages of a fire, occupants in
certain areas will not be expected to evacuate, the configuration of alarm zones might require approval by
the authority responsible for the enforcement of fire safety legislation in the building.