Where a purpose-built block has adequate compartmentation and a suitable stay-put strategy, a communal fire alarm is normally not required simply because the building contains flats. Different arrangements may be needed for conversions, simultaneous evacuation strategies, mixed-use buildings or other special circumstances.
Why stay-put blocks are different
Purpose-built blocks of flats are commonly designed so that each flat forms a fire-resisting compartment. If a fire starts in one flat, the occupants of that flat leave, while residents in unaffected flats are normally safer remaining in their homes unless fire or smoke affects them or the fire and rescue service instructs them to leave.
Why a communal alarm can be inappropriate
Government guidance explains that communal alarms are not normally appropriate where adequate compartmentation supports a stay-put strategy. A general alarm can encourage occupants who would otherwise be safe to enter corridors and stairs that may be affected by smoke.
When an alarm may be needed
A communal alarm may be appropriate where the building operates a simultaneous evacuation strategy, where the original compartmentation cannot reasonably support stay put, in some converted buildings, or where particular mixed-use or specialist housing arrangements create a different risk profile.
Smoke detection for other systems is not the same thing
Detectors in common parts may be provided to operate automatic smoke vents or other fire-safety systems without sounding a general evacuation alarm. The presence of detectors therefore does not necessarily mean that the building has, or should have, a communal warning system.
Do not change the strategy casually
Installing or removing a communal alarm can affect the whole evacuation strategy. Where the current arrangements appear inconsistent, the issue should be considered through the fire risk assessment and, where necessary, by a competent fire-alarm or fire-safety specialist.