Portable gas detection equipment exists to help ensure a work or home space is free of hazardous gases. In the workplace, in some industries, this is more than a safety issue, it is a matter of life or death. Gas detection equipment, however, only works if it is set up to work correctly. Follow these tips to ensure your portable multi-gas detector always works when you need it to work and its results are accurate.
Calibration is Key
Like any piece of equipment, a portable gas detector is only as accurate as it is calibrated, or measured to be. If your portable gas detection equipment is calibrated incorrectly, it will not give accurate readings of gas concentrations. That can be a deadly situation as you may not know you are in proximity of a deadly or combustible gas until something bad happens.
The only way a gas detector will work properly is if it is tested against known percentages. If, for example, your detector indicates trace amounts of deadly gas, but your test sample is heavily permeated with the gas, you know your equipment is not functioning properly. The quantity of gas has to be known and quantified or you have no way of measuring accuracy.
Causes of Calibration Issues
There are many things that can cause “drift” with calibration:
- The sensors in the equipment are degrading or need to be maintained
- Consistent exposure of the sensors to highly corrosive gases
- Incorrect storage procedures
- Overexposure to high concentrations of the target gas
- Extremes in environmental conditions (high humidity, bitter cold, intense heat)
There are two methods of testing gas detection equipment: A bump test or a full calibration. Each has its role.
Bump Test: A bump test exposes the equipment to known quantities of gas and the results of the detection equipment are measured against the known quantity. If the results fall within an acceptable range versus the actual concentration amount, the calibration is verified.
Full Test: If a bump test result is not within an acceptable tolerance range, a full test has to be completed. With a full test, the tolerance range is tightened as much as possible. So if a test gas sample is 10% carbon monoxide, the equipment’s reading will be calibrated to that amount. All full test results need to be certified by and traceable to the NIST standards. Full tests are rarely needed and usually only needed after a bump test failure or after the equipment has been serviced.
The accuracy of your portable gas detection equipment must be beyond any question. It is literally a matter of life or potential injury or death for your employees. Understanding the testing process will help you better set a test schedule for your equipment.