Smoke Detectors
In the UK many people die or are injured in domestic fires every
year, many of these are from smoke inhalation. These figures could
be reduced by installing and maintaining domestic smoke alarms.
Where are self-contained smoke alarm systems required?
- new dwellings
- extensions to existing dwellings
- roof conversions
Self-contained smoke detector is not recommended for use in
kitchens, garages or places where steam, condensation of fumes
could give rise to false alarms. More appropriate and effective
detectors area available for such situations, eg heat
detectors.
It is also recommended that detectors be interlinked to form a
system and not independent units. Also, smoke detectors may be
wired to a lighting circuit, this is so that if the lighting fails
then so will the alarm system and it is very likely that a failed
lighting system will be repaired quickly.
Choosing a smoke detector
Domestic smoke detectors come in two basic types:
- Ionization Smoke Detector
These work by measuring the reduction of an electrical current when
smoke particles enter a special chamber.
- Optical Smoke Detector
These contain a small photoelectric cell, which triggers the alarm
when the beam is disturbed by smoke.
Research has shown that ionising detectors often are a little
quicker to react to hot blazing fires than optical detectors. While
optical detectors are better at detecting smouldering fires of the
sort that might be started by a cigarette having fallen down the
back of a sofa or chair. This means that an ionising detector might
be better if situated in a corridor near a kitchen as it is less
likely to be set off by burning toast, but would react quicker if
the toaster were on fire. However, there is not a lot to choose
between either Ionization of Optical smoke detectors.
When purchasing a smoke detector ensure it complies with a
British Standard or the International Standard Organisation (ISO)
standard. A self-contained smoke detector must comply with British
Standard 5446 part 1 1990, for automatic fire detection, and to
British Standard 5839 part 1 1988, for alarm systems.
Never buy a second-hand smoke detector. Always look for the
British Standard kite mark or the CE mark.
Smoke detector can be powered
- By batteries in the unit
- From mains supply
- From mains with battery back-up
Mains wired with battery back-up is a requirement for compliance
with Building regulations in flats and houses.
This webpage was updated on
1/20/2010