F3200 Operator's Manual Document No: LT0119
System Testing and Maintenance
Page 10-6 29 July 2002 Issue 2.04
10.4 PREVENTION OF FALSE ALARMS
Fire detection systems rely on sensors to identify atmospheric or environment changes
brought about by the presence of fire. They employ various types of sensors to monitor
specific conditions. These devices signal a warning when an abnormal condition exists,
indicating either the presence of a fire or the immediate likelihood of an outbreak.
There are detectors to monitor heat, flame, water pressure or the presence of
combustion products such as smoke or gases. However, some or all of these conditions
may appear in different locations when there is no fire present. For example:
(a) HEAT SOURCES; The sudden increase in local temperature when a furnace
door is opened can trigger heat sensors.
(b) DRAUGHTS, DUST, STEAM, CHEMICALS; Wind-induced surges of dust,
release of steam or chemicals can cause smoke detectors to generate an alarm
signal.
(c) ENVIRONMENT CHANGES; Changes to wall partitions, Air-Duct position or air
velocity can cause detectors to be forced into continuous alarm.
(d) CONSTRUCTION AND MAINTENANCE ACTIVITIES; Portable welding units
can activate flame detectors, while spray-painting 'drift' can trigger smoke
detectors.
It is therefore highly recommended that the service company be notified of any proposed
physical, environmental or occupancy changes.
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