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Net Safety Monitoring
Field of View
The area in front of a flame detector, where a standardized flame can be
detected and which is specified by distance and angle off the central axis, is
the Field of View. The referenced flame is moved to 50% of the maximum
on-axis detection distance and then moved off-axis horizontally and
vertically to the limit of detection. These off-axis angle limits specify Field
of View.
Table 2: Field of View Testing
Field of View Testing
Fuel
Size
Hydrogen(H2)
24" Plume
NOTE: Data based on Maximum Sensitivity
Setting.
Installation Considerations
The following should be considered when mounting flame detectors.
Point detector toward where the flame is expected.
Ensure an unobstructed view of the area to be monitored.
Employ more than one detector to ensure the hazard is fully covered.
The detector should be accessible for cleaning the window/lens and
reflector surfaces.
Tilt detector downward a minimum of 10 to 20
accumulation which could obscure the detector's viewing window.
Securely mount detector so as to reduce vibration as much as possible.
MAN-0101 Rev 01 UVIRS-H2-A/H2-AR & UVIRS-H2-A-X/H2-AR-X
November 23, 2012
Horizontal
Degrees
128(+65, -63)
°
to reduce dirt and dust
When located outside, detector sensitivity can be reduced by heavy fog,
rain and/or ice.
Reduce sensitivity setting if false alarms, related to surrounding activities,
occur (refer to "System Sensitivity" )
When installed near or on water (such as an off shore platform), be sure to
take into account the low horizon level when tilting detector downward.
UV radiation, other than that produced by an actual fire, is referred to as
"background UV". An example of a high level of background UV could
be a flare stack situated outside of a building. The UV radiation produced
by this flare, in conjunction with a false alarm IR source, may be
detected as fire when a door to the building is opened. Windows or other
reflective surfaces may also cause unusually high levels of UV radiation
to enter the building from the flare. In a situation like this, the fire
detection system response must be carefully checked and the sensitivity
level adjusted high enough so that this "background UV" will not cause
false alarms.
UV fire detectors respond to radiation other than ultraviolet. X-rays in
conjunction with a false alarm IR source can activate the detector. Since
X- rays are often used in industrial inspection it may be necessary to
disable the system when inspections are conducted nearby.
For protection against line surge and extraneous transients, it is required to
install detector wires in a braided flexible conduit less than 5 feet.
Note: CSA approved models (UVIRS-H2-A/AR) are not supplied with a
locking collar. ATEX approved models (UVIRS-H2-A-X/H2-AR-X) are
supplied with locking collar.
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