How to reduce false fire alarms

False alarms cost money, disrupt work and sleep, and teach people to ignore the sound that is supposed to save them. Many fire and rescue services now ask for confirmation before attending automatic alarms from some premises, or charge for repeated false alarms. The good news is that most unwanted alarms have a small number of causes, and most of them can be fixed.

Start with the logbook

Every false alarm should be recorded in the logbook with the time, the device and the likely cause. Without that record, it is guesswork. When we look at a site with a false alarm problem, the first step is always the logbook and the panel's event history. Patterns usually jump out: the same detector, the same time of day, or the same activity.

The usual causes

• Cooking fumes and toast near optical smoke detectors, especially in kitchenettes and staff rooms.
• Steam from showers and kettles drifting into corridors.
• Dust from building work, cleaning or warehouse activity.
• Aerosols such as deodorant, hairspray and air fresheners.
• Vaping and smoking under detectors.
• Contractors working on site without isolating the right zone.
• Accidental call point operation, often by trolleys or children.
• Ageing or dirty detectors that have become oversensitive.

Practical fixes

• Change the detector type. A heat detector, or a multi-sensor detector that combines heat and smoke, can be far more stable near kitchens and bathrooms.
• Move the detector. A detector right outside a bathroom door or above a toaster can often move a couple of metres with no loss of protection.
• Fit call point covers. Hinged covers stop accidental knocks but still allow deliberate use.
• Introduce a hot work and contractor procedure. A permit that requires zones to be isolated, and reinstated, prevents the most avoidable alarms.
• Review the cause and effect. On larger systems, a short investigation delay for some detectors, where the fire strategy allows it, gives staff time to check before a full evacuation.
• Replace end-of-life detectors. Many manufacturers recommend replacing smoke detectors after around ten years.

What not to do

Never cover, disconnect or remove a detector because it keeps going off. If a detector is in the wrong place, have it moved or changed by a competent person, and record the change. A disabled detector in a building where people sleep can be the difference between escape and tragedy.

When to ask for help

If you are having more than a handful of false alarms a year from the same system, ask your fire alarm engineer for a false alarm review. BS 5839-1 gives a framework for investigating and reducing unwanted alarms, and a good engineer will work through it with you.