Fixed detectors are used to detect an irregular or dangerous presence of gas in a specific area, with the function, of alerting your environment in case of potential threats. Equipped with sensors or cells, fixed gas detectors can measure the concentration of one or several types of gas, depending on the type of gas detector. Toxic gases are monitored and measured in parts per million (ppm), while oxygen is measured in a volume percentage. Combustible gases are typically measured between 0 and 100% of the lower explosive limit (LEL). When fixed gas detection is used, all detectors emit a signal before reaching the set alarm value.

Unlike portable detectors, fixed gas detection secures an entire area 24 hours a day. The detector can be connected to a detection system, which displays the gas concentration in numerical value, and then activates the servo controls in case of anomalous value.