Mounting Below A Ceiling - Honeywell FSL100-IR3 Technical Handbook

To avoid the shadow effect (in zones that cannot be fully monitored by a solo flame detector) place a second flame detector in
the opposite corner.

4.6 Mounting Below a Ceiling

Smoke rises and can form a layer at ceiling height long before naked flames are visible. Dense smoke can block some of the
wavelengths of light given off by flames, and this can ultimately decrease the sensitivity and speed of the flame detector.
To avoid the risk of smoke blocking their fields of view, you should mount the FSL100-IR3 flame detectors at least 0.5 m (2 ft),
and the FSL100-UV and FSL100-UVIR detectors at least 1.5m (6 ft), below the ceiling (see dimension 'D' below).
Reducing the height of a detector above the monitored item will increase the size of shadow areas, so a
minimum of two detectors will be required to cover the shadows. See Shadow Effect explanation above.
MAN0987_Iss 2_09/16
INSTALLATION
Figure 6. Shadow Cancelling
D m
o
45
Figure 7. Mounting Clearance
Caution
11 FSL100 Series Flame Detectors
Technical Handbook