The way the system works is , if a detector in a flat activates . The alert tone will sound in that flat only for around 4 minutes . This gives the occupant chance to deal with the situation to avoid it going to a full fire alarm. If after the 4 minutes the smoke has cleared , then the alarm silences itself and resets . If however , after those 4 minutes , smoke continues to be present … or during the 4 minutes a second detector in the same flat activates , then the evacuation tone will sound … but still in the affected flat only . This is not automatically silenceable, and the fire service will attend and deal with the alarm . The reason the full alarm will not sound site wide is to support the stay safe / stay put policy . If the building is to be evacuated then the fire service can activate the necessary alarm sounders . In terms of communal detection and call points , they have no delay on them at all and will alert the fire service straight away … but these will still sound in the communal areas only.
@@thelittledesigner4417 it uses a verification delay on the panel . The alert tone in the affected flat will sound for 4 minutes , and that gives the occupant the chance to deal with the alarm and clear the smoke . If the smoke is still there after the 4 minutes or a second detector activates during that time … the alarm will change from the alert tone to the evacuate tone . This will still only sound in the affected flat . However, it will cause a full fire condition on the panel .. and will send an alert to the monitoring centre who will dispatch the fire service. Communal devices do not have any delays on them , but will sound the evacuation tone straight away in the communal areas only . There are 81 flats in the building and do not want to evacuate the entire property unless absolutely necessary . There is a KAC key switch next to the panel which will sound all sounders if it’s needed to evacuate
