Specifications

3
cause of ignition of furniture or bedding is by a cigarette. Ionisation types are considered to be
more suited for use in rooms where a fast flaming fire may present a greater danger, dining rooms
and bedrooms being possibilities. The standard now recommends that in new build properties heat
alarms should be installed in kitchens and the 'Principal habitable room' eg the living room; in
addition to any smoke alarms used in the escape routes. It is anticipated that Building Regulations
Document B applicable in England and Wales will follow these recommendations when revision takes
place shortly.
The electrical specifications are as follows:-
Voltage Supply - 230 Volts AC
Frequency - 50-60 Hertz
Current - 40mA
Power - 0.8 Watts
LOCATION
They should be sited on the ceiling, close enough to a potential source of fire so they can respond
quickly. The Building Regulations requires that the installation of self-contained mains powered
Smoke Alarms in all new and refurbished dwelling houses should, at least, meet the following
requirements:
- Within 7.5m of any door to a room where a fire is likely to start.
- on each storey of a multi-storey dwelling.
- all Smoke and Heat Alarms in the dwelling should be interconnected.
BS 5839: Pt.6 broadly supports these recommendations for alarm systems in existing dwellings,
adding that alarms should be sited no more than 3m from bedroom doors so that they can be
more easily heard if a fire should occur during the night. We would recommend the fitting of
alarms in all rooms (apart from bathrooms and shower rooms) for the earliest possible response.
Very large dwelling houses may require more elaborate alarm systems and the relevant sections of
BS 5839: Pt.6 should be consulted for specific guidance.
One smoke alarm in each of the circulation spaces of a property is the minimum recommendation.
This would normally be the hallway, and the landings of any subsequent floors. However, the only
way to achieve good coverage is to install an alarm in every habitable room. Building Regulations
currently requires the installation of a heat alarm in the kitchen if there is no door separating it
from the circulation spaces. Please note: circulation spaces could be a lounge or dining room in a
property where there is no hallway and the stairs lead off a living area.
In summary, they should not be sited in Kitchens, Bathrooms, Shower rooms Garages or other places
where there are likely to be excessive nuisance alarms from steam, fumes and high levels of airborne
contamination. Heat Alarms are considered more suitable for use in Kitchens and Garages, but not
Bathrooms or Shower rooms or places where the normal temperature can exceed 40
O
C.
6. What are the
Technical
Specifications?
7. Where should
they be sited?
8. How many do I
need?
9. Where shouldn’t
Smoke Alarms
be sited?