GasSens Gas Detection System Section 5 - A11-10 Br
2
Sensor/Transmitter
O & M Manual
Revision E, 10/15 5 - 4
SENSOR LOCATION
Bromine gas is heavier than air and will tend to accumulate near the floor in a closed room with
little air movement. If there is good air circulation in an enclosed area, some bromine will undoubtedly be
carried throughout the area. Bromine gas sensors should be located one to two feet off the floor in closed
storage rooms, but may be located at higher elevations in outdoor areas or where good air flow will quickly
mix any leaking gas throughout the space. Outdoor sensor locations require that prevailing wind patterns,
likely personnel work areas, and most probable leak sources all be evaluated to determine where sensors
will detect leakage with the shortest response time.
INTERFERENCES
The A11-10 sensor/transmitter uses an electrochemical sensor manufactured by ATI. It is
designed to measure Br
2
gas concentration in air with a maximum of sensitivity and a minimum of
interference from other gases.
Unfortunately, electrochemical sensors are not 100% selective and do exhibit response to other
gases that may be present in ambient air. Table 5-1 lists the possible interferences that may be encountered
when using the Br
2
Detector. The table indicates the relative response of the bromine sensor to 1 PPM of
the listed gas, expressed in terms of relative PPM bromine signal. For example, exposure of a bromine
sensor to a gas sample containing 1 PPM of Cl
2
would produce a signal equivalent to 1 PPM of chlorine.
A negative sign (-) indicates an interference that could cause low Br
2
measurements if a mixture of
bromine and that gas were encountered.
TABLE 5-1
INTERFERENCE RESPONSE
FLUORINE 1.0
CHLORINE DIOXIDE 0.7
CHLORINE 1.0
OZONE 0.05
NITROGEN DIOXIDE 0.2
HYDROGEN SULFIDE -0.1
HYDROGEN CYANIDE -0.05
METHYL MERCAPTAN -0.04
SULFUR DIOXIDE -0.01
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