Construction of the various devices
Gas detectors. Explosimeter – toximeter – oxygenometer

Gas detectors are classified into three main types: fixed detectors, transportable detectors and portable detectors. They can be designed to detect a single type of gas (a single-function device such as an explosimeter, for example), or several types of gas (a multi-function device such as a portable multi-gas detector, where several gases may be detected: for example a flammable gas (CH₄ or another gas), oxygen(O₂), carbon monoxide (CO) and hydrogen sulfide (H₂S).

They operate by diffusion or can be fitted with a pump, which brings the gas to be detected inside the device. The detection head is either integrated into the device, or remote from the electronics, the latter also comprising a part in the remote head, and a part in a measurement bay.

Fixed detectors are connected to a central gas detection system as a minimum, or can be integrated into an...