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Avoid the 7 deadly sins of gas detection

Sin #3 Using the wrong equipment

Using the wrong equipment is the third of Crowcon’s Deadly Sins of Gas Detection. The best of gas detection intentions can be undermined by use of the detection equipment not up to the job. There are many ways in which the accuracy and safety of gas detection equipment can be inadvertently compromised but there are some errors which can be easily avoided. To illustrate the point, here are some examples:

The wrong sensor technology

Choosing the correct sensor technology relies on more than knowing which gases to test for. The local environment can have a critical impact on sensor performance. Consider sensor technologies for flammable gases:

Can it be poisoned?

Pellistors are generally suitable for detecting flammable gases, such as hydrogen and hydrocarbons. However, they can be poisoned or inhibited by some chemicals, like silicons and sulphur based compounds. In environments where these substances are likely to be encountered, an IR sensor may be a better choice.

Is it cross-sensitive?

An IR based sensor may be a good choice for hydrocarbons. However, it will not detect hydrogen. For this, an electrochemical sensor may be the right choice. Then again, carbon monoxide can cross react with electrochemical hydrogen sensors, giving an inaccurate reading. If both carbon monoxide and hydrogen are present, a pellistor should be considered for detecting hydrogen.

But it goes beyond selection of the best sensor technology. There are plenty of other ways inappropriate equipment can put lives in danger.

Equipment not built for the conditions

A good example of this is equipment for offshore environments. Extreme temperatures, high winds, high seas, ice and high salt levels all make it essential to use detectors made of suitable materials. Detector heads should be made of 316 stainless steel. Other grades of metal will corrode due to the high salt levels from the sea spray, and very quickly the heads will need to be replaced.

Confined space entry without a pumped unit

Correct confined space entry (CSE) requires specific equipment. A detector without a pump (or aspirator) will only detect gases in its immediate vicinity. A pump draws air towards the detector from within the confined space. This ensures that no one entering is stepping directly into hazardous conditions.

Unnecessary additional hazards

A fixed detector without a remote display may demand working at height to take a read-out. Temporary area monitors connected by cable rather than wirelessly are a potential trip hazard. Portable gas monitors that can't resume a TWA calculation if switched of during a break could risk over exposure to toxic gases. Even use of inappropriate products to clean a detector can inactivate a sensor.


There is so much more to this subject. For instance, we haven't touched on use of PID sensors for flammable gases. Hopefully it has highlighted the variety of factors to think about when considering the most appropriate gas detection to use in your work place.

Informed decisions on gas safety can only be formed by a thorough understanding of the hazards presented by different working environments, and the capabilities and limitations of each detection technology. The experts at Crowcon can help to ensure that you are not relying on the wrong equipment to provide safety for your site and its employees.

More Information

Get professional advice from Crowcon, the expert in gas detection, call us on 01235 557 777.