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How to Avoid Nuisance Fire Alarms
33
We all realise when life, buildings, production facilities, etc. should be protected, it is of
utmost importance that an initial fire is detected as soon as possible. That's why more
reliable automatic fire alarm systems are installed.
In an automatic fire alarm installation, especially if smoke detectors (sensors) are used,
everybody in the building needs to be informed how to avoid nuisance fire alarms.
To avoid troubles and unnecessary expenses there are a couple of things to bear in mind.
Here are some advices and tips.
Tobacco smoke
The detectors (sensors) cannot differentiate between different types of smoke. They cannot
separate tobacco smoke from smouldering smoke. Intensive tobacco smoking in
conjunction with poor ventilation can cause a fire alarm.
Welding, grinding, cutting, sawing & drilling, these types of activities may generate smoke.
Carpet welding
Welding of plastic carpets causes a smoke that can be almost invisible, but it still influences
the smoke detectors (sensors).
Cooking fumes, toasting & candles
It is not only "normal smoke" that influences smoke detectors (sensors). It is all kinds of
"combustion products", caused by cooking (frying/grilling), toasting, etc.
Warning: Be careful when smoke detectors (sensors) are mounted near / close to such
activities.
Special environments
Certain premises and environments can influence smoke detectors (sensors) and cause
alarms. It can be ions (from plastics), flour dust, oil haze, aerosols, strong perfumes, strong
ventilation, insecticides, disinfecting sprays, etc. If many odd and unnecessary alarms
occur, the environment must be examined and perhaps other detector types have to be
chosen.
Steam / hot air
Smoke and heat detectors are influenced by steam and hot air, e.g. from an oven, dry-
blower, heater, etc.
Exhausts
Exhausts from cars / trucks, lift trucks, lawn mowers, etc. influences smoke detectors
(sensors). If windows and doors are open, exhausts can "slip in" that way.
Lack of maintenance
Smoke detectors (sensors) are influenced by their environment and become "dirty". In an
analogue system (like FT1020G3), a Service signal is given when it is time to clean or
exchange the smoke detectors (sensors). The alternative is to exchange detectors at even
intervals, to be on the safe side.
Change in activities or wrong choice of detector
If the activities in the premises are altered, the detector choice might also need altering.
Due to some of the special environments shown above, an in-appropriate detector type
might have been chosen from the beginning and thus cause unnecessary alarms.
Actions via EBLWin
Choosing another type of detector, e.g. a multi detector (with both heat and smoke
detection), can solve certain problems. Note that the coverage area can be different for
different types of detectors.
It is however not always the best action is to change detector type. Here is a list of other
actions, programmed via EBLWin, which can be used:
Another alarm algorithm can be used (e.g. during working hours).
•
Alarm Delay Facility (ADF) for analogue smoke sensor / detector and sounder
•
bases combination can be used.
171
Operation Manual
FT1020G3 Rev 2.10.4
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