The Health and Safety Executive (HSE) have issued a safety alert highlighting the risk of misleading gas detection readings following a fatal injury.

Gas detection may be used in support of risk assessments associated with, for example, hot work or confined space entry. The appropriate selection of the correct gas detection system ensuring that it is suitable for the intended purpose and gives a sufficiently accurate and reliable indication of the presence of the hazardous material is therefore of extreme importance.

Pumped gas detectors can be used to sample locations at a distance from the detector via a sampling tube and are commonly used.

In a recent incident, a gas detector failed to detect a flammable atmosphere.  Hot work proceeded based on the false reading.  The hot work resulted in ignition of a flammable atmosphere and a fatal injury.

Whilst there were errors in the selection and set-up of the gas detector, the most significant contributor to the failure of the gas detector was the adsorption of the flammable vapour on the surface of the sample tube before it could reach the gas detector.

The aim of the safety alert is to remind operators of the need to ensure the suitability of gas detection system for their intended purpose.

Full details of the Safety Alert can be found at the HSE Website.