Det-Tronics OPECL Infrared Hydrocarbon Gas Detector - Manual (Page 12)

10 95-8556 10.1
Consideration of the following system location guidelines
is also recommended:
lED visibility
Select a mounting orientation where the Open Path
Eclipse status indication LED is visible to personnel
within the area.
module Separation Distance
The transmitter and receiver modules must be installed
directly facing each other across the area to be
protected. Physical obstructions in the direct line of
sight between the modules are not permitted. The
overall line of sight distance between the modules must
not fall outside the specified operating distance range
(refer to “Specifications” for details).
multiple System Installations
If multiple OPECL systems are to be installed, ensure
that each receiver can view only the intended transmitter.
System mounting Elevation
In all cases, the modules should be installed at the same
elevation above grade to ensure that alignment capability
and foul weather performance are not compromised.
For detection of lighter than air vapors such as methane,
installation of modules at approximately 2 meters above
grade minimizes typical beam block conditions due to
human activities, while enabling satisfactory detection
capability. For detection of heavier than air vapors,
installation of detectors below the expected leakage
source is generally recommended unless nuisance
beam blocks will occur at an unacceptable rate. In
this case, identification and analysis of application
specific conditions should be completed to determine
the optimum installation elevation.
Sources of heavy Contamination
Avoid locations where high levels of contaminants will
persistently be blown onto the detector windows. Potential
sources of heavy contamination include generator /
turbine exhausts, flarestacks, drilling equipment, process
vents / chimneys, etc. If sources of heavy contamination
cannot be avoided, consider fitting extra shielding and/or
providing good access for routine cleaning.
Snow and Ice in ambients below –20°C
The heated optics on both modules will melt snow or
ice on the windows in ambient temperatures down to
approximately –20°C. Below this temperature, snow
or ice blown onto the window will not be melted until
the ambient temperature rises. If longterm outdoor
operation in very cold climates is intended, extra
shielding / covers are recommended to prevent
accumulation of snow and ice on the windows.
Deluge and flooding
The modules are rated IP66/IP67 and will not be
damaged by occasional deluge or flooding. However,
during such an event, the unit will completely lose it’s
IR signal and will enter the “Beam-Block / Fault” state.
In addition, when the deluge / flooding subsides, there
is the possibility that contaminants will be left on the
windows. Install the modules away from areas prone to
deluge or flooding.
areas prone to Subsidence and Settling
Avoid installation of the modules in areas where
problems with subsidence, settling or thawing of
permafrost can occur or cause significant movement.
If such locations cannot be avoided, the foundations
of the mounting structure should be engineered to
minimize any angular movements between the receiver
and transmitter.
areas prone to Earthquakes
In the event of an earthquake, there is a chance that the
modules will become misaligned with respect to each
other. As long as the modules do not suffer from direct
mechanical impact damage during an earthquake,
they should remain undamaged by such events. After
an earthquake, it is recommended that the system
alignment be checked. Anti-vibration mounts are
unlikely to be of any benefit and are not recommended.
misalignment by accidental Impact
Locations where there is a significant likelihood of
equipment, personnel or moving objects accidentally
knocking the modules out of alignment should be
avoided where possible. If such locations cannot be
avoided, measures including improved mechanical
protection and warning notices should be considered.