What Is Gas Sensor Calibration?
Gas sensors, like any sensor that measures a variable value, require regular calibration. During calibration, gas sensors are tested to see if they can provide an accurate reading of the gas concentration to which it’s exposed.
If the gas sensor misreads the gas concentration, the calibration process automatically adjusts the sensor to read it correctly. Calibration ensures the alignment between the measuring instrument and the measured variable. Adhering to a proper gas sensor calibration schedule ensures that it reads gas concentrations correctly.
Why Do Gas Sensors Require Regular Calibration?
Gas sensors lose their accuracy through a process of calibration drift. Calibration drift refers to slow changes in gauge responsiveness. Over time, the sensor’s readings can become too sensitive or not sensitive enough. Numerous factors contribute to this drift, such as:
- Environment. A gas sensor’s sensitivity suffers when operating in harsh environments or stored in extreme temperatures. High humidity or dense concentrations of air particulates can also degrade a sensor’s calibration.
- “Poisoning.” Extremely high concentrations of the intended gas can also lead to calibration drift.
- Time. As your gas sensor ages, the chemical composition and electronic alignment of your sensors degrade.
- Damage. Unfavorable storage or operating conditions can damage a gas sensor. Drops, exposure to water, or other physical contacts can reduce sensitivity. Regular vibrations or the jostling of equipment result in excessive and premature calibration drift.
Eventually, the calibration drift is so extreme that you can no longer calibrate your gas sensor. At this point, you need to replace the sensor.
What Is the Correct Gas Sensor Calibration Schedule?
How often gas sensors require calibration is a common question, and it depends on various factors. The Canadian regulatory agency, the Occupational Health and Safety, recommends that owners follow the manufacturer’s recommendations and that the safest and most secure method of verifying a gas sensor’s reliability is daily testing by direct exposure to the targeted gas. This process is often referred to as a “bump test.”
However, your gas sensor calibration needs ultimately depend on your usage and application. Different users require unique gas sensor calibration schedules. Two divergent types of gas sensor users include:
- Critical gas sensor user. An organization may require gas sensor calibration that it can present in a court of law. To remove any doubt about the accuracy of the readings, this user needs to calibrate the sensor before and after each test or series of tests.
- Less frequent gas sensor user. Other organizations may use their sensors much less frequently. They may only use their gas sensors a few times each year for less critical situations. Such sensors only need require calibration after each use.
Most users fall in between these two extremes, so you should tailor a gas sensor calibration schedule to your needs. Always consult your manufacturer for their recommendations.
What to Consider When Setting Your Gas Sensor Calibration Schedule?
Besides manufacturer recommendations, you need to assess your gas sensor use when considering your calibration schedule. You may want to start by calibrating them once per week, and if they require minimal adjustment, you can extend the time between calibrations. If you notice that the sensor requires a larger adjustment, you should reduce the interval between calibrations.
Learning the behaviors and requirements of your gas sensors can take time. On the other hand, you can hire professionals to do it for you. The highly trained and experienced technicians at All Protect Systems, Inc. can handle all of your gas sensor needs.