VOICE ALARM OR VOICE-EVACUATION SYSTEMS

A voice alarm system uses amplifiers and speakers in an arrangement similar to a public address system. It is possible to use the system for public address or background music purposes although this is not allowed for UL and FM-approved applications.

Typical arrangements include a stored message that is broadcast on alarm, either an alert or an evacuate message, or both, or there may be a tone generator that gives a sound like a siren, and there will be a fire microphone which can over-ride the other inputs.

 Reasons for using a Voice-Evac system

          Voice evacuation systems are an asset in circumstances where  the occupants of a premises are not familiar with evacuation procedures or may need directions during an emergency. 

Voice evacuation systems are also an advantage where a two-stage alarm is called for, or where a phased evacuation is required.

Forthcoming European regulations will require voice evacuation systems where more than 500 members of the public are expected, or where the buildings exceed three stories in height.

Voice evacuation systems can also assist in the fire fighting effort if used to direct operations.

Where there are many hazardous (Ex) areas the use of a voice evacuation system can usually be more cost-effective than explosion-proof or intrinsically safe sounders.

Where a building will have a PA system or background music it is often cost-effective to use a combined PA/Voice-Evac system, although this is not acceptable in UL approved applications.

Naturally the installation would then require a high audio quality and also have to meet the standards required of a voice-evac system.

    Points to consider.

All voice-evacuation systems are required to meet the standards required of fire alarm sounder circuits:

a.      The speaker circuits must be wired in fire-rated cable with CWZ rating.

b.      The circuits must be monitored for open-circuit and short-circuit faults.

c.      There must be battery backup to ensure the system will drive the outputs for half an hour after being without mains power for 24 hours.

d.      Consideration should be given to laying out the circuits so that a circuit failure will be compensated for by the proximity of other circuits.

In addition the control equipment for the voice evacuation equipment must be fully monitored, including wiring to microphones. Spare amplifier capacity should be available to cater for an amplifier failing. This can use either a manual changeover switch or a ‘hot-swap’ automatic switching arrangement.  

Detailed consultation with the equipment supplier is essential when designing voice-evacuation systems as the range of system components and their features and capabilities must be fully understood.

Follow the link below to Signet AC who manufacture our Voice Alarm equipment: