Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector - Manual (Page 8)

6 95-8440 9.3
INSTALLATION
iMPoRtant
use only low vapor pressure silicone grease
when lubricating threads on the PointWatch
Detector and associated termination box. Do
not get this grease on the optics of the detector.
A suitable grease is listed in the “Spare Parts”
section at the end of this manual. Do not use
Hydrocarbon-based grease. Doing so will emit
hydrocarbon vapors that will be measured by the
detector, resulting in inaccurate gas level readings.
DETECTOR LOCaTION
It is essential that the device be properly located to enable
it to provide maximum protection. The most effective
number and placement of sensors varies depending on
the conditions at the job site. The individual designing
the installation must rely on experience and common
sense to determine the type and quantity of sensors and
the best sensor locations to adequately protect the area.
The following factors should be considered for every
installation:
1. What kind of gas is to be detected? If it is lighter
than air, place the sensor above the potential gas
leak. Place the sensor close to the floor for gases
that are heavier than air or for vapors resulting
from flammable liquid spills. However, note that air
currents can cause a gas that is heavier than air to
rise. In addition, if the gas is hotter than ambient air
or mixed with gases that are lighter than air, it could
also rise.
2. How rapidly will the gas diffuse into the air? Select
a location for the sensor as close as practical to the
anticipated source of a gas leak.
3. Ventilation characteristics of the immediate area
must also be considered. Movement of air may
cause gas to accumulate more heavily in one area
than another. The detector should be placed in the
areas where the most concentrated accumulation of
gas is anticipated. Also take into consideration the
fact that many ventilation systems do not operate
continuously.
4. Proper orientation is horizontal.
Figure 6—Tall PIRTB with Window
Figure 7—Short PIRTB
Recommended Orientation of the PIR9400
CORRECT INCORRECT