Detcon DM-100 - Manual (Page 41)

Model DM-100
DM-100 Instruction Manual Rev. 3.3 Page 37 of 40
8.4 Proper Application and Maintenance of Acrylonitrile Sensor
Acrylonitrile (ACN) is a very dangerous toxic gas that has OSHA and NIOSH TWA limits of 1 and 2 ppm
respectively. It has an IDLH (Immediately Dangerous to Life and Health) limit of 85 ppm and a 15 minute
ceiling limit exposure of 10 ppm.
The Detcon Model DM-700 Acrylonitrile Sensor is based on an electrochemical sensor which has certain
limitations of use. Although it has good original span sensitivity to measure acrylonitrile, it has been known in
certain application cases to lose sensitivity over time.
Continuous exposure to background ACN levels or repeated high ACN exposures will cause the sensor’s
response to ACN gas to be lost, and hence its useful life be shortened.
It is not reliably suitable for strict industrial hygiene monitoring where the application goal may be to assure
that the ACN levels remain below the 2 ppm TWA limits.
When properly maintained it does offer the ability to function as gross leak detection method for ACN
releases.
The lowest recommended scale range for ACN is 0- 50 ppm. The lowest recommended alarm set limit is 4
ppm.
Sensor Warranty is 6 months (this shortened warranty period reflects the vulnerability to unpredictable losses
of sensitivity).
Using appropriate PPE, the sensor should periodically be span calibrated with ACN target gas (or occasionally
bump tested with ACN target gas). However, frequent exposures to ACN during calibrations and bump testing
will also shorten the life of the sensor. To address this, it is possible to use Carbon Monoxide (CO) as a cross-
calibration gas, but CO may only be used if it is in combination with a program of periodic ACN bump testing
that confirms the ultimate ability to adequately sense the ACN should a release occur. If the ACN bump test
result is not acceptable, then a formal ACN span calibration must take place.
The end-user should work with Detcon to assure that a suitable amount of replacement Plug-in sensors are
available on hand to handle the ongoing exchange of sensors that may require periodic replacement.