Detcon PI-700 0-500ppb - Manual (Page 9)

Model PI-700 0-500ppb
PI-700 0-500ppb Instruction Manual Rev. 0.0 Page 5 of 53
(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) Maintenance access
(6) Additional placement considerations
Density
Placement of sensors relative to the density of the target gas is such that sensors for the detection of heavier
than air gasses should be located within 4 feet of grade as these heavy gasses will tend to settle in low lying
areas. For gasses lighter than air, sensor placement should be 4-8 feet above grade in open areas or in pitched
areas of enclosed spaces.
Leak Sources
The 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.
Maintenance Access
Consideration should be given to providing easy access for maintenance personnel. Consideration should also
be given to the consequences of close proximity to contaminants that may foul the sensor prematurely.
NOTE: All installations of the gas sensor should point straight down (refer to Figure 7).
Improper sensor orientation may result in false readings and permanent sensor damage.
Additional Placement Considerations
The sensor should not be positioned where it may be sprayed or coated with surface contaminating substances.
Painting sensor assemblies is prohibited.
Although the sensor is designed to be RFI resistant, it should not be mounted in close proximity to high-
powered radio transmitters or similar RFI generating equipment.
Mount in an area void of high wind, accumulating dust, rain or splashing, direct steam releases, and
continuous vibration.
Do not mount in locations where temperatures will exceed the operating temperature limits of the sensor.
Where direct sunlight leads to exceeding the high temperature-operating limit, use a sunshade to help reduce
temperature.