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Smoke detectors

Most fires happen at night when people are asleep. Smoke from a fire will send people into a deeper sleep. Smoke alarms give an early warning of fire which gives people time to act before being overcome by dangerous fumes and smoke.

Video - Importance of having a working smoke alarm

Fire detectors and alarm systems

It is now a requirement of the building regulations that all new dwelling houses are to be provided with mains powered fire detection and alarm systems with battery back-up. A typical new 2 storey house will require a smoke detector in the entrance hall, first floor landing, all bedrooms and all high risk rooms such as the living room and utility room. A heat detector is also required in the kitchen. All these detectors should be inter-linked so that if one detector detects a fire then all detectors are sounded. Ensure that smoke alarms are located at ceiling level and not on walls and that all smoke alarms are properly installed and maintained. Test the alarms regularly.

You should look at the above video which shows the importance of having a smoke alarm. This man's house was engulfed in a fire. His life was saved by his dog after she woke him up while he was sleeping. 

Further information on system grades, types and installation of smoke alarms can be obtained from Technical Guidance Document B.

In existing houses we recommend that you install at least one smoke alarm on each floor level (for optimum use the smoke alarm on each floor should be located on the ceiling and should be checked regularly).


  • Check your smoke alarm regularly
  • Replace your battery regularly
  • Standard battery detectors require the battery to be replaced yearly or whenever they start to beep
  • There is no need to change the battery in the units powered by a 10 year battery as the entire unit should be replaced after 10 years
  • The battery in the mains powered units should be replaced when they start to chirp
  • Clean the outside of your alarm with the soft brush of the vacuum cleaner every six months

False alarms

If your smoke alarm activates accidentally there is generally a button (normally the test button) to silence the alarm. The detector will reset itself to normal mode after ten minutes.

Page last reviewed: 26/01/23

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