Brooks ALARM 2000 - Ionisation Model; Heat Model

Site Manual
Alarm 2000 Iss 5
8
3.1.4 Ionisation Model
Ionisation Smoke Alarms respond to a sufficiently wide range of
fire to be of general use and they are particularly responsive to
fast flaming fires where little visible smoke may occur. They are
seldom troubled by dust or insect contamination. However,
ionisation alarms are vulnerable to irritating nuisance alarms
caused by cooking fumes or oil / gas heaters. Furthermore
ionisation alarms will be slower to respond to smoke produced by
slow smouldering fire.
This type, with consideration to the above, can be installed in
passageways and areas leading to bedrooms.
Operating Principle
Radioactive source ionises the air molecules within the sensing chamber.
Advantages
 Least expensive
 Dual chamber compensates for changing ambient conditions
 Less prone to false alarms due to dust and steam
 Suitable for general use
Disadvantages
 Contains radioactive material – Americium 241 0.9 microcurries
 Prone to false alarms due to fumes from cooking or gas/oil heaters
 Not sensitive to dark smoke from a slow smouldering fire.
Brooks models: EIB160e, EIP146RC and discontinued EIPFSITL.
3.1.5 Heat Model
Heat Alarms require the least maintenance of any Alarm. There
are locations where the installation of a Smoke Alarm is not
recommended, eg kitchens, laundries etc. Yet these areas are a
potential of fires and the need for an alternative method of fire
detection is, in the opinion of many fire officers and specifiers,
essential in this and other vulnerable locations of residential
properties.
The Heat Alarm provides such an alternative. Fixed temperature
heat alarms are designed to trigger when the temperature
reaches 58 degC. (136 degF.). The Heat Alarm is not sensitive
to smoke, but in a closed room with a vigorous fire they will tend
to respond faster than a smoke alarm a distance away in the hallway. A Heat Alarm MUST
be interconnected to your Smoke Alarms so that the alarm can be heard throughout the
building. This type, with consideration to the above, can be installed in kitchens, laundry’s,
garages and boiler houses and other areas where there are normally high levels of fumes,
smoke or dust i.e. places where Smoke Alarms cannot be installed without the risk of
excessive nuisance alarms.
Operating Principle
Thermistor sensor - resistance value varies with temperature.
Advantages
 Ideal for those areas where protection is deemed necessary but where the use of
Smoke Alarms will cause constant false/nuisance alarms i.e. kitchens, garages or
laundries
Figure 2 EIB161e
Figure 3 EIB164e