Evacuation signal lasts 24 seconds and consists of 4 sound bursts and 2 verbal messages
Alert Signal is a repetitive sound and may have verbal messages
Verbal messages must include "evacuate" and fire or emergency. Must be clearly spoken and readily understandable.
The whole building must have the same alerting devices.
- Sounders 5dBA above any background noise
- Voice 10dBA above any background noise
- Minimum sound levels of 65dBA
- Maximum sound level of 100dBA at 1.8m
- Sleeping areas minimum of 75dBA at bed head
Visual devices must be perceptible by the occupants.
- Where ear protection must be worn 90dBA these are required in addition to alerting devices.
When alerting devices can cause distress or prevent emergency functions from operating smoothly, other suitable methods are permissible:
- Where staff operate a 24 hour wakeful watch, low level devices may be used at the work stations.
- Other areas may have low level devices to alert occupants and do nut need to comply with the above levels.
- Staff member may silence devices but not visual devices.
Hospitals and care homes may use strobes and low noise level devices that pulse at the same rate as the strobe flashes.