Deadly Sin No. 1 – Calibration
Calibration, or lack thereof, is the first guide in the series describing the seven deadly sins in gas detection from the specialist Crowcon. In collaboration with Crowcon, we aim to make leaders and employees more aware of how they can avoid the consequences of lack of calibration and thereby save lives.
What you need to know about calibration
“It worked fine last time”
Laziness is one of the main reasons why much gas detection equipment is not calibrated. The safety that an apparently functional gas detector provides can give the user a belief that there is little or no risk in using it. However, the problem is that a gas detector must measure accurately to maintain safety.
Extremes and exposure
Factors that can affect the performance and accuracy of a gas detector can include:
- Adverse working conditions
- Extreme temperatures or humidity
- Exposure to contaminants such as silicone or solvents
- Exposure to excessively high concentrations of gas
- Mechanical shock or stress
Any of these factors can lead to a gas detector providing an inaccurate measurement, which can mean that the detector may not alarm in the presence of toxic or flammable gas levels.
Crowcon’s calibration checklist
To make it very simple, there are three steps in calibrating a gas detector to verify and reset the detector’s response to the gas to be measured:
- Step 1: Reset the detector in fresh air (and make sure it is fresh!) or in synthetic air
- Step 2: Expose the detector to a known concentration of the target gas
- Step 3: Adjust the detector until it shows the correct level of gas
The expert dimension
For some gases, such as flammable gases and volatile organic compounds (VOCs), an alternative method may be necessary for calibrating detectors. Here, calibration can be performed using a similar gas, and a cross-calibration factor is used to determine the accuracy of the detector.
Nothing should be left to chance in calibration. In addition to following the manufacturer’s recommendations, an experienced user will also consider flow paths and flow rates, pressure, temperature, humidity, cross-sensitivity, response time of the gas cell, and discharge of the waste gas.
Calibration can save lives
There are many factors that can compromise the accuracy of detectors and therefore endanger the lives of the people who use them. These factors make it essential for users to understand that scheduled calibrations save lives. It is also important for managers to have a strict procedure to ensure that calibration is performed at the scheduled time and that the correct calibration test is used.
