Given that the properties of gases vary, some gases rise and some gases fall, it is useful to enhance the operation of the gas alarm by installing additional (optional) sensors at different heights. This allows both rising and falling gases to be detected.

To make optimal use of a gas alarm in general, it is highly recommended to work with (at least) two sensors. One sensor can be mounted at a height of +/- 30cm above the floor for detection of falling gases; the 2nd sensor -for rising gases- should then be mounted at least 1.50m high and at least 20 cm below the ceiling.