5
PRS-UM-BTN-EN-Rev02-02.2019
case of high gas concentrations there is not enough oxygen in the sensor to perform oxidation
process correctly. Hence the measuring signal decreases at high gas concentrations and even
can lead to measuring signal within the measuring range again. A connected controller must
be operated with alarm devices, outputs, and alarm thresholds operating as latched if the
measuring range is exceeded. In this case do not reset latching alarms without having ensured
a safe condition by means of an independent gas concentrations measurement.
2. Minimum Oxygen Concentration
The measuring principle of heat of reaction needs a minimum oxygen concentration of 12 %
by vol., otherwise the measuring values will be too low because of oxygen deficiency.
3. Long-term Gassing With Methane At Very Low Temperatures
If the Prosense BTN series detectors are operated applying with methane at very low
temperatures, the measuring signal at longterm exposition may decrease after alarm
activation and may lead to misinterpretation.
If a gas alarm occurs, necessary actions need to be taken immediately. The decrease of the
measuring signal should not mean that the gas concentration has been decreased. We
recommend to keep alarms on the associated controllers and not to reset these alarms
without performing measurement with an independent gaz detectors to make sure conditions
are safe.
