DM-634C Oxygen Sensor Assembly
DM-634C O2 Sensor Instruction Manual Rev. .066
Page 7 of 25
3.5.2
Sensor Location
Selection of sensor location is critical to the overall safe performance of the product. Five factors play an
important role in selection of sensor locations:
(1) Density of the gas to be detected
(2) Most probable leak sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Accessibility for routine maintenance
Density
- Placement of sensors relative to the density of the target gas is such that sensors for the detection of
heavier than air gases should be located within 2-4 feet of grade as these heavy gases will tend to settle in low
lying areas. For gases lighter than air, sensor placement should be 4-8 feet above grade in open areas or in
pitched areas of enclosed spaces.
Leak Sources
- Most probable leak sources within an industrial process include flanges, valves, and tubing
connections of the sealed type where seals may either fail or wear. Other leak sources are best determined by
facility engineers with experience in similar processes.
Ventilation
- Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a
manner where the migration of gas clouds is quickly detected.
Personnel Exposure
- The undetected migration of gas clouds should not be allowed to approach
concentrated personnel areas such as control rooms, maintenance or warehouse buildings. A more general and
applicable thought toward selecting sensor location is combining leak source and perimeter protection in the
best possible configuration.
Note
:
For products utilizing the aluminum junction box option, the conduit seal shall be
placed at the entry to the junction box (see Figure 6 as an example). For products utilizing
the stainless steel junction box option, the conduit seal shall be placed within 18” of the
enclosure. Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.
3.5.3
Local Electrical Codes
Consideration should be given to easy access by maintenance personnel as well as the
consequences of close proximity to contaminants that may foul the sensor prematurely.
