Free tools
Voice alarm calculators, with the working shown
Free calculators for Public Address Voice Alarm (PAVA) systems: the standby battery a system needs under BS 5839-8:2023 Annex C, and the amplifier power each zone needs for a budget quotation. Each one lists every assumption it made beside the result. No email, no callback, just the number.
Voice alarm has its own family of standards, and the figures in a quotation can be checked against them. These tools exist so the person responsible for a system can check a number before signing for it, and so the technician sizing a replacement can show where the number came from.
What should a year of maintenance include?
Maintenance Proposal
Ten questions about your site, and back comes every inspection and test across the year and the reports you should receive. Then check what you're getting now against it. No prices, no email.
Changing who maintains your voice alarm?
The Takeover Check
Seventeen questions, most of them yes or no. Back comes which handover records you hold, who owes the rest, and what the incoming maintainer should check under Clause 41.1. No email needed.
Not sure where to start?
System health check
Eight questions about your system and what matters to you. Your answers come back with things you can do yourself, and a sheet to print. No email needed.
Is your voice alarm battery quote too high?
Voice alarm standby battery calculator
Sizes the standby battery to BS 5839-8:2023 Annex C: 24 hours of standby, then at least 30 minutes of evacuate broadcast in every alarm zone, with the 1.25 allowance for ageing and temperature (Clause 25.3.5 and Annex C, C.1). The ProAudium battery method derives the derating factors from the battery's own published data, which can make the answer smaller than a quotation built on a borrowed factor. Three levels, from two questions to full manual control.
Does the battery current rise and fall as you measure it?
Quiescent current calculator
Where the line monitoring checks the loudspeaker lines in pulses, enter the current between pulses and during one, the pulse and the period. Back comes the time-weighted quiescent current with the working shown, and one click takes it into the Battery Calculator at Level 2.
How much amplifier power does your building need?
ZOE, the Zone Output Estimator
Pick a space type for each zone, sketch its areas, duplicate the zones that repeat, and ZOE returns loudspeaker counts and an indicative amplifier power per zone and for the building: enough for a manufacturer to return a budget quotation. Everything runs in your browser.
Why can't people understand the announcements?
Hear the room
Pick a space, a loudspeaker type and how many loudspeakers, and hear the same announcement as a listener in that room would, from a small office to a station-sized concourse. It shows the critical distance and whether the listener is inside it, and lets you hear what more loudspeakers, or one closer loudspeaker, change.
What STI will we get?
STI estimator
Enter the room's size and finishes, or its reverberation time and noise, and get an estimated Speech Transmission Index (STI) range, with the chance of a reading of 0.50 or more. The room sets the ceiling, so the honest answer is a range, not a promise. Everything runs in your browser, and the result needs no email.
Does Martyn's Law affect your venue?
Martyn's Law checker
Ten questions, two minutes, no email required to see your result. It gives a steer on your likely tier under the Terrorism (Protection of Premises) Act 2025 and on a question that's easy to leave until last: whether the existing PAVA can carry the communication procedure.
What happens after the number
Every result is complete on its own. Below each battery and amplifier result sits one optional extra: a checked, signed calculation sheet returned by a named person, for anyone who wants a second pair of eyes on the inputs. Nothing about the result depends on asking. The method behind each tool is on its page, and the battery series in the Knowledge Hub shows the working in full, starting with Your next voice alarm battery quote should be smaller than your last.