Viewpoint: gas calibration is a real ‘lifesaver’

Dangerous gases are hazards in many industries, but for the most part, the knowledge and technology exists to ensure that everyone stays safe. Yet there are still so many deaths every year.

Through our business as gas detection specialists, we regularly encounter failings that could, in a worst-case scenario, cause fatalities or, at the very least, life-changing injuries.

In order to give guidance on how to avoid such situations, we have come up with a series of blog posts under the banner ‘Seven Deadly Sins of Gas Detection’.

By highlighting the most common causes and effects of each ‘sin’, we want to provide managers and employees with a greater awareness of what we believe are the ‘Seven Deadly Sins’ of gas detection, how to avoid them and save lives.

We regularly encounter failings that could, in a worst-case scenario, cause fatalities or, at the very least, life-changing injuries

These articles highlight the most serious pitfalls and so promote gas detection safe practices. Issues covered include what happens when there is no bump testing, the wrong equipment is used, vital training is ignored, and no notice is taken of false or ‘spurious’ alarms.

However, here we will be focusing on the first sin on our list: the sin of not calibrating your detector.

There are many factors that can compromise the accuracy of detectors and therefore compromise the lives of the people using them. These factors make it essential for operators to understand that scheduled calibration is a lifesaver. It is also essential for managers to take a rigorous approach to ensuring that calibration is performed on-time and the correct calibration test is being used.

Don’t jump to conclusions

Complacency is a major cause of not calibrating gas detection equipment. The safety provided by an apparently functional gas detector can lead to the assumption that there is little or no risk. The problem, however, is that for the assurance of safety, a gas detector has to be monitoring accurately.

Factors that can compromise the performance and accuracy of a gas detector include: adverse working conditions, extremes of temperature or humidity, exposure to contaminants such as silicone or solvents, and exposure to high concentrations of gas, mechanical shock or stress.

Any of these factors can lead to a gas detector displaying an inaccurate reading, and this can mean that the detector may not sound an alarm even in the presence of toxic or flammable levels of gas.

Calibration checklist

There are three steps to calibrating a gas detector to check and reset the detector’s response to a target gas:

Step 1: Zero the detector in fresh air or 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 of calibrating detectors may be required. Here, calibration can be carried out using a different, related gas and a cross-calibration factor is applied to determine the accuracy of the detector.

Calibration should leave nothing to chance. In addition to following the recommendations of the detector’s manufacturer, an expert will take into account flow paths and flow rates, pressure, temperature, humidity, cross sensitivities, the time required for the sensors to respond and the expulsion of the waste gas.

• Nick Dajda is product manager at gas detection specialist Crowcon.