Faulty gas detection instruments can be fatal. There are many factors in the workplace that can cause a gas detector to fail. Here are the top eight.
Dirt, dust and water impact. These physical affects can block gases and vapours from entering the sensor chamber preventing detection of the gases. This can be either within the sensor area, sampling pump or sample lines.
2. Physical Affects
Dropping and other abuse can damage the instrument from working properly or at the least change the ability of the detector from measuring accurately.
3. Gas Exposure
High gas exposure will change the calibration curve of the sensors causing false or inaccurate readings. Extremely high concentrations can kill the sensor’s ability to measure gas. Further, many sensors can fail but not provide a warning that they have failed. In fact, many provide a zero (0) indication on the meter reading which suggests they are working correctly when they are not.
4. Catalytic Sensors Affected by Poisons and Inhibitors
Catalytic combustible gas sensors can be poisoned by silicone based compounds and airborne lead. These kill the sensor. Inhibitors such as sulphur compounds and chlorinated compounds reduce the sensors response (ability to measure). This can slow the sensor response and in some cases reduce the sensor’s ability to measure some gases. For example, being able to measure pentane but not methane due to the reduced sensitivity.
5. Electrochemical Sensor Poisoning
In this case sensors can be poisoned by other gases which are absorbed into the sensor chamber and react with the electrode catalyst.
6. Temperature Affect
Storing instruments in environment which is either too cold or too hot can affect the ability of the sensors to measure accurately.
Moisture condensing on or in sensor: this can happen to oxygen sensors when moisture condenses in the capillary tube in the sensor. It will cause the sensor to fail.
8. Calibration Drift
All sensors from all manufacturers drift over time. Calibration brings the sensor back into equilibrium and provides accurate readings.
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