Frequently asked questions

One device in every circulation space on every storey, plus one inside or immediately outside every sleeping room, plus a heat detector in the kitchen and CO detection where combustion appliances or an integral garage exist — all interlinked. A typical three-bedroom, two-storey house ends up with four to six devices.

Optical is the better default for homes: it responds well to the smouldering fires that modern furnishings produce and produces far fewer cooking nuisance alarms. Ionisation responds faster to open flaming fires. If only one technology can be fitted in a dwelling, optical is the safer choice.

Not reliably — a significant proportion of children under ten sleep through a conventional 85 dB alarm. Fit a device inside each child's bedroom, keep bedroom doors closed at night, and rehearse the escape plan during the day.

Ten years for the whole device. The chamber contaminates and sensitivity falls invisibly, so an older unit can pass its test button and still detect far too late. Write the installation date on the device.

No. It leaves the household with no detection and does not solve the placement problem. Use the hush button, then relocate the device or change the sensing technology.

Yes for dwellings in most of Europe, North America and Australia, with the detail varying by country and often by tenure. See the standards and regulations page and then confirm locally.

Not in bathrooms, not within about three metres of a hob, not in the dead-air wedge within roughly 10 cm of the wall-to-ceiling junction, not within 1 m of vents, fans or doors that create draughts, and not in a garage, workshop or loft unless the device is rated for that environment.

Yes if there is a kitchen, and for garages, laundries, dusty workshops and cold stores. Heat detection never replaces smoke detection where people sleep.

An alarm senses and sounds by itself. A detector only senses and reports to a control panel. The two are certified to different standards and used in different buildings.

It is the difference between protecting a room and protecting a household. A fire behind a closed door far from the bedrooms may never be heard without it.

Cooking aerosol, steam and suddenly disturbed dust all behave like smoke inside a scattering chamber. Each has a specific fix, and the decision tree on the false-alarm page identifies which applies to you.

Weekly with the test button, and the interlink annually by triggering one device and confirming that all the others sound.

Never. Paint blocks the chamber vents, so the device still looks installed while being effectively disabled. Buy a housing in the colour you want instead.

Yes wherever there is a fuel-burning appliance or an integral garage. Smoke and CO are different hazards with different sensors and different standards.

It earns its place where nobody is in the building for long periods, or where a relative living alone should generate a notification. The device must still work entirely offline at full sensitivity.

It is the minimum a certified domestic alarm must produce under defined test conditions. Distance, closed doors, soft furnishings, background noise and hearing loss all reduce what a sleeper actually receives.

In domestic installations, a well-planned radio interlink is reliable. Its failures are predictable — concrete, metal cladding, lift shafts and metal racking attenuate the signal, and exceeding the maximum number of linked devices degrades the mesh.

Log the time and what was happening fifteen minutes earlier, three times. The pattern usually names the cause. If none emerges, swap the device with a known-good unit: if the fault moves with the device, replace it; if it stays with the location, it is a placement problem.