Net Safety UV/IRS-H2-A, User Manual

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Net Safety Monitoring
MAN-0101 Rev 01 UVIRS-H2-A/H2-AR & UVIRS-H2-A-X/H2-AR-X 7
November 23, 2012
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
Horizontal
Degrees
Hydrogen(H2)
24" Plume 128(+65, -63)
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
°
to reduce dirt and dust
accumulation which could obscure the detector’s viewing window.

Securely mount detector so as to reduce vibration as much as possible.

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.