14.1 Commentary

In buildings, fire alarm strategies vary based on complexity and size. Here's a condensed summary of the evacuation strategies and requirements:

1. Simple Evacuation Strategy:

In smaller buildings, any fire alarm or manual call point activation triggers fire alarm sounders throughout the entire building for full evacuation.

2. Complex Evacuation Strategy:

In larger buildings, the initial "Evacuate" signal might be limited to specific areas (e.g., a single floor).
An "Alert" signal might be used in other areas to warn occupants without requiring immediate evacuation.

3. Alarm Zones:

Buildings are divided into independent alarm zones, where sounders in each zone can operate independently (silent, "Alert," or "Evacuate").
Reasons for alarm zones include:
Phased evacuation.
Minimizing disruption from false alarms.
Implementing a two-stage alarm system.

4. Fire-Resisting Separation:

Each alarm zone must be separated by fire-resisting construction to ensure occupants in adjacent zones remain safe.
In complex public buildings like shopping centers, smoke curtains might replace fire-resisting construction, with voice messages used instead of standard alarm devices.

5. Regulatory Approval:

The configuration of alarm zones may require approval from fire safety authorities to ensure compliance with safety regulations.

14.1 Recommendations

The following recommendations are applicable.

a) The boundaries of every alarm zone (other than external walls) should comprise fire-resisting construction.

b) The extent of any overlap of signals between alarm zones should not be sufficient to result in confusion of occupants in any area of the building.

c) A common signal should be used throughout all alarm zones to convey the need for evacuation, and a (different) common signal should be used throughout all alarm zones for any alert signal that can be given by the system.

d) While an alarm zone may incorporate more than one detection zone (but not vice versa), the boundaries of alarm zones should coincide with the boundaries of the relevant detection zones (see Figure 3).

e) The user or purchaser should ensure that, where appropriate, the configuration of alarm zones is approved by the relevant enforcing authority or authorities.

Figure 3 — Alarm zones (see 14.2d)

14 Alarm zones