12 Note: This document is based on the recommendatio ns of BS5839 Part 1: 2002. I t is intended only as a guide to the ap plication of fire detection systems.
Reference must be made to relevant national and local stan dards.
Detector type Application Not suitable for
Ionisation smoke detector General purpose smoke detector – bet ter
for fast flaming fires
Areas subject to smoke, steam, dust or
dirt during normal use
Optical smoke detector General purpose smoke detector – bet ter
for smouldering fires
Areas subject to smoke, steam, dust or
dirt during normal use
Photo-thermal multi-criteria de tector General purpose detector – good fo r
smouldering and fast flaming fires
Areas subject to smoke, steam, dust or
dirt during normal use
Optical beam smoke detector Large and high rooms Areas subject to smoke, steam, dust or
dirt during normal use
Rate of rise heat detector Areas s ubject to smoke, steam, dust or
dirt during normal use
Areas subject to rapid changes of
temperature or temperatures over 43°C
Fixed temperature detector (5 8°C) Areas subject to smoke, steam, dust or
dirt and rapid changes of temperature
during normal use
Areas subject to temperatures over 4 3°C
High temperature fixed detector (7 8°C) Areas subject to smoke, steam, dust or
dirt and temperatures over 43°C during
normal use
Areas subject to temperatures over 6 5°C
Figure 2.3.3. Operation of Reflective Type Optical Beam
Smoke Detector
Beam detectors are more complex to inst all than ordinary
point smoke detectors and it is advisab le to consult an
application guide for the use of projecte d beam smoke
detectors before considering the u se of these detectors.
Figure 2.3.1. Selection of Fire Detectors
Up to 100M
Up to 25m height
Combined
Emitter /
Receiver Unit
Reflector
Beam
attenuated by
smoke plume
Application Guide