Positioning of Smoke & Heat Alarms

The positioning of your smoke and heat alarms is important in order to ensure effective detection in the event of a fire. Each smoke and heat alarm will have positioning instructions within the supplied user manual; however, please find below some helpful tips and a basic guide to the position of detectors within the home. Please note: it is your responsibility to make sure that the detector locations comply with any applicable building regulations.

Flat Ceiling

Smoke alarms should ideally be installed in the centre of the ceiling. It is recommended to position the alarm at least 300mm away from walls and light fittings/decorative objects (See fig 1.). This is because air does not circulate effectively in corners, and objects like light fittings can obstruct smoke and heat from entering the sensor chamber.

As hot smoke initially rises and then spreads out, smoke alarms should be located on the ceiling. This is so that smoke can reach the detector's sensor chamber as early as possible. If it is not possible to install the smoke detector on the ceiling, the unit can be installed up to 575mm below it. A heat detector should also be located directly on the ceiling; however if this is not possible, the unit can be installed up to 125mm below it.

Sloped Ceiling

With a sloped ceiling the position of a smoke or heat detector needs to be measured vertically from the peak. Smoke alarms can be installed within 600mm and heat detectors can be installed within 150mm of the peak (See fig 2.). Again, it is important to try and position the detector as central to the ceiling as possible.

Fig 1. Positioning on flat ceilings

Fig 2. Positioning on sloped ceilings

Please note: The measurements stated above are a general guideline. Different manufacturers recommendations may vary.

Reviewed: 05/02/2021 (doc:45 V1.1). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.