What do the technical specifications for

combustible gas detectors mean?

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Typical technical specs

• Detection range: 0-6,400ppm (Methane).
• Alarm sensitivity: 40ppm (Methane).
• Calibration: Automatic.
• Power Source: 4 x AA batteries (included).
• Classifications: Class B, Division 1.

Detection range

The detection range of a gas detector refers to the levels of gas the instrument can detect. The unit PPM stands for parts per million. This is more a reference to proportion than a tangible unit: 1PPM is roughly equivalent to four drops of water in a bath.

Alarm sensitivity

This is refers to the levels of gas at which the alarm will activate. It is possible to purchase gas detectors which have multiple sensitivity levels. The example specification means that the alarm will be activated when there is 40PPM (0.004%) of gas, which is highly sensitive.

Calibration 

To calibrate is to adjust the measurement to a pre-determined standard. Gas detectors are generally self-calibrating – this will occur every time you switch on your device and will take a few seconds. There will be a signal to indicate when it is complete.

Power source

Gas detectors are portable and their power comes from batteries. The technical specifications will clarify which type are required for that specific gas detector, as this does vary between models.

Classification

The classification system used is a Canadian one – the Workplace Hazardous Materials Information System (WHMIS). Class B, Division 1 simply refers to combustible gases. The products are often manufactured by foreign companies, which is where the system cross-over may occur.