January, 2016 120-11
Model F120 UV/IR Flame Detector
SELECTING A LOCATION FOR THE FLAME DETECTOR
!
NOTE: The determination of the location of ame detectors should be made in
accordance with any relevant local, municipal, and national standards, codes, or
legislation. Seek the advice of professionals or experts with knowledge of process
plant systems and/or safety and engineering personnel.
Considerations
To insure the fastest possible detection of ames, the location of the detector is important.
There are no standard rules for detector placement since the optimal placement of the
detector(s) are different for each application. The following considerations should be made
when locating ame detectors:
• The ame detector must have an unobstructed view of the area it is intended to protect.
• Detectors should be installed in an area as free of shock and vibration as possible
• Although the detector has been designed to recognize sources of false alarms and
prevent it from being activated, it is virtually difcult to eliminate all the varying factors that
may trigger a false alarm. Determine an optimum location to place the detector to reduce
or eliminate these sources of false alarms.
• A clear view of the detector for visual inspection and convenient access for cleaning
• In areas with dirty atmospheric conditions, the detectors will require frequent inspection
and cleaning
• In high trafc areas, the detector should be placed a minimum of 10 feet from the
protected area to ensure ample coverage and to prevent obstructing the eld of view of
the detector by personnel working or machines passing by
• For outdoor installations exposed to intense, direct sunlight, utilize a sunshade to protect
the detector from extreme temperatures
• Do not begin installation unless all considerations regarding the location of the detector
have been taken into account.
Optical Sensitivity Range
The distance at which the ame detector will respond to a re is a function of the intensity of
that re. The F120 has a maximum detection range of 70 feet (21 m) for an n-Heptane re
with a surface area of 1 sq ft (0.093m
2
).
Field of View
Flame detectors exhibit reduced sensitivity to ames that are not directly in front of them (on
axis). Relative sensitivity at various off axis angles is described in the eld of view diagram.
It denes the detector sensitivity as a function of ame location in the eld of view. For
example, if the ame is located directly in front of the detector, an angle of zero degrees (0°)
the detector will respond to the standard 1 square foot n-Heptane re at a distance of 70
feet (21 meters). At 30° off axis, the sensor sensitivity is approximately 85% of the on-axis
sensitivity; resulting in a reduction of the effective range of the detector to about 55 feet (17
meters). Note that the worst case detection range for the detector will be a range of 35 feet
at 45° off-axis.
Utilize the eld of view diagram and a drawing of the area to be protected in specifying the
mounting elevation and detector orientation. Where required, additional F120 units should
be utilized to insure adequate coverage.
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