When a tone sounder goes off, people do not immediately leave. They look around, ask colleagues, gather belongings, or assume it is a test. That delay before movement begins is a well-documented part of evacuation, and it is often longer than the walking time to the exit.
A voice alarm shortens it. A clear instruction — what has happened, what to do, which way to go — removes the ambiguity that causes hesitation.
What a PAVA system is
Public Address and Voice Alarm combines a life-safety evacuation system with everyday public address. The same amplifiers and loudspeakers can carry announcements or background music day to day, then switch under fire alarm control to broadcast pre-recorded evacuation messages, with a fireman's microphone for live instruction.
Because it is life-safety equipment, it is built to a different standard than ordinary PA: EN 54-16 covers the voice alarm control equipment, EN 54-24 covers the loudspeakers, and the system needs monitored circuits, standby power and fault reporting.
Where it is normally needed
Voice alarm is expected wherever occupants are numerous, unfamiliar with the building, or cannot evacuate simply. In practice that means shopping centres and retail, hotels, hospitals and clinics, airports and terminals, stadiums, large offices and educational campuses. It is also the enabling technology for phased evacuation, where floors are cleared in a controlled sequence rather than emptying a tall building at once.
Intelligibility is the whole point
A voice alarm that cannot be understood is worse than a sounder, because it consumes time without conveying information. Intelligibility is measured — commonly as STI or STIPA — and it is designed in, not adjusted at the end:
- Loudspeaker density. Many quieter speakers, spaced properly, beat a few loud ones. Even coverage avoids both dead spots and painfully loud zones.
- Room acoustics. Hard, reverberant spaces — atria, stairwells, warehouses — smear speech. They need directional speakers and careful placement.
- Ambient noise. Message level must sit above the working noise floor, which is why plant rooms and factory floors need separate treatment.
- Message design. Short sentences, unhurried delivery, a clear voice, and an attention-getting tone before speech. Multiple languages where the audience needs them.
Zoning
Zones should follow the evacuation strategy and the fire compartmentation, not the convenience of the cabling. Get this right and you can alert one floor while advising those above to stand by; get it wrong and you either evacuate a whole site unnecessarily or send a message into an area it does not apply to.
Integration and resilience
PAVA takes its trigger from the fire detection system through an agreed cause-and-effect matrix — which alarm in which zone produces which message where. That matrix should be written and signed off before commissioning, then demonstrated during it.
Resilience requirements that matter: monitored speaker circuits so an open or short is reported rather than discovered during a fire, amplifier redundancy or spare capacity, battery standby sized to the required duration, and fire-rated cabling on circuits that must survive.
Practical guidance
- Require an acoustic design with predicted coverage, not just a speaker count.
- Have intelligibility verified by measurement at commissioning, in representative locations.
- Agree the message set and languages early — recording and approval always take longer than expected.
- Include PAVA in the routine fire alarm test regime, and rehearse use of the fireman's microphone with the people who would actually use it.
TSB Smart Tech supplies, installs and configures PAVA and public address systems integrated with EN 54 fire detection — including recent work for Toyota Iraq. Contact our engineers to discuss your building.