The short answer
Most false fire alarms come from something the detector cannot tell apart from a fire, such as cooking fumes, steam, dust or aerosol spray, or from a detector of the wrong type or in the wrong place. To reduce them, record every activation and its cause, change detectors to types suited to the room (for example multi-sensor or heat detectors near kitchens and showers), re-site badly placed devices, and have the system reviewed at each service visit.
The most common causes
Toasters, grills and kitchens with doors left open next to smoke detectors.
Showers and bathrooms, especially in care homes, hotels and HMOs.
Contractors cutting, sanding or drilling without the detectors being covered or the zone isolated.
Deodorant, hairspray, cleaning sprays and vaping near a detector.
An optical smoke detector where a heat or multi-sensor detector would do the job without reacting to fumes.
Detectors too close to kitchens, air vents, doors to outside or ceiling fans.
Contaminated or old detectors, damaged wiring and poorly maintained panels.
Call points knocked or pressed on purpose. Protective covers help.
Step by step: how to cut false alarms
- Record every activation in the logbook: date, time, zone, device and the cause if known. Patterns only show up when it is written down.
- Find the cause of each one before resetting and moving on. The same device going off twice is a sign something needs changing.
- Match the detector to the room. Heat or multi-sensor detectors near kitchens and bathrooms, and optical smoke detectors where smoke is the likely first sign of fire. BS 5839-1 gives guidance on selection.
- Re-site badly placed detectors, away from kitchen doors, vents and steam.
- Control contractor work with a permit: isolate or cover detectors in the work area, and restore them the same day.
- Have it reviewed at every service. A good servicing engineer looks at the false alarm record and recommends changes, not just a reset.
Why it matters now
Many UK fire and rescue services no longer attend automatic fire alarms from some commercial premises during the day unless someone confirms there is a fire. Check your local service’s policy. Repeated false alarms also lead staff and residents to ignore the alarm, which is the real danger. In care homes and hotels, where people sleep on site, reducing false alarms is part of keeping the evacuation plan credible.
Our engineers review false alarms at every visit as part of fire alarm servicing. In one Stockport care home, false alarms fell by around 80% in the quarter after the panel was replaced (see the case study).
Common questions
Why does my fire alarm keep going off for no reason?
Usually because a detector is reacting to something that looks like smoke to it, such as cooking fumes, steam, dust or aerosols, or because the detector is the wrong type, badly sited, dirty or faulty. Recording each activation and its cause is the first step to fixing it.
Can I disable a detector that keeps going off?
Not without a plan. Disabling a detector removes protection from that area. A competent engineer should find the cause and change or re-site the device, with any temporary measures recorded in the logbook.
What detector is best near a kitchen?
A heat detector or a multi-sensor detector is normally used near kitchens instead of an optical smoke detector, because cooking fumes are less likely to set them off. The choice should follow BS 5839-1 and your fire risk assessment.