Can intelligent multi-sensor fire detectors reduce false alarms in my business under BS 5839?
Written by Chris Goodman, Commercial Director · Last reviewed 15 October 2026
The short answer
Yes. Multi-sensor detectors, which combine smoke with other signals such as heat, can reduce false alarms from things like steam, dust and aerosols, and are a recognised option under BS 5839-1. They must be chosen and positioned by a competent fire alarm designer, and every false alarm should still be investigated and recorded.
Why false alarms matter
False alarms disrupt your business, and repeated false alarms lead people to ignore the real thing. Many fire and rescue services now limit their response to automatic alarms from some premises, or recover costs for repeated false alarms, so reducing them has a direct cost benefit too.
How multi-sensor detectors help
A standard optical smoke detector reacts to particles in the air, so it can be triggered by steam, cooking fumes, dust or aerosols. A multi-sensor detector combines more than one input and applies logic to tell the difference between a real fire and a likely false alarm. Some products are marketed as using AI, but the principle is the same.
What BS 5839-1:2025 expects
BS 5839-1:2025 replaced the 2017 edition in April 2025. It places a strong emphasis on limiting false alarms, including investigating and recording every unwanted alarm and taking corrective action where needed.
Before you change detectors
- Find out what is causing your false alarms first. The fix may be as simple as moving a detector or changing how an area is used.
- Make sure any change is designed by a competent fire alarm designer and does not reduce the protection your fire risk assessment relies on.
- Update your fire risk assessment and fire alarm records afterwards.
This answer is general guidance on the law in England and is not a substitute for advice on your specific premises.
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