Installing a smoke detector

Number & location
Fire brigades and smoke detector manufacturers recommend the installation of at least two alarms for double the protection. In two-storey buildings, one detector should go in the hall and the other on the landing, so sleepers get a vital early warning if a fire starts in the house.

It's also worth fitting an alarm in a child's room, and in a utility room if you are in the habit of running your washing machine or dishwasher overnight.

According to Home Office statistics, almost a quarter of all smoke alarm failures are due to their location, so make sure your entire house is protected.

What to look for
When you are buying the detectors, check the packet carefully. Smoke detectors must comply with BS 5446 Part1.

Ionisation alarms are better at detecting tiny amounts of smoke from a blazing fire. The optical types are more suitable for detecting smouldering fires. You can also buy alarms that combine both types of detector in one unit.

How to install
Detectors should be fitted on the ceiling at least 300mm (12in) from any light fittings and not directly above sources of heat, such as a radiator. If you can't fit a detector on the ceiling, screw it to the wall, between 150 and 300mm (6 and 12in) from the ceiling. Read the instructions provided to attach the detector. You should be able to make small holes in the ceiling plaster with a bradawl to take the fixing screws. Ideally, the detector should be screwed into a ceiling joist. Find the nearest ceiling joist by tapping the area with your knuckle - a dull thud will indicate the joist position. Screw the detector to the ceiling and fit a new battery. Press the test button to make sure the alarm works. You should replace the battery at least every year and press the test button once a month or so to check the device is working.