Height Matters: Gas Detector Mounting Height

Generally speaking, sensors should be placed near the source of the gas if possible. For example, near the compressor or piping. They should be placed in areas where there is good air circulation, but not in the path of rapidly moving air.

Sensors should not be placed near ventilation fans or openings to outside. Pay particular attention to "dead air spots" where there is little or no air movement.

Consideration should be given to accessibility for calibration when locating sensors. For example, a sensor mounted 30 feet off the floor would be difficult and maybe even hazardous to service.

COMBUSTIBLE GASES

Combustible gases are monitored to protect a building from blowing up or burning down. Where the gas sensors are mounted depends on the type of gas being monitored.

Combustible gases that are lighter than the ambient atmosphere, like ammonia, natural gas (methane), hydrogen or acetylene will build up in the highest areas of the building and are best detected with a gas detector mounted on or near the ceiling.

Combustible gases that are heavier than the ambient air, like propane, refrigerants, ethanol and butane will collect in the lower area of the building and will be detected fastest near the floor.

TOXIC GASES

Toxic gases are monitored to protect people's health. A general rule of thumb for monitoring many toxic gases is to mount the gas detector in the "breathing zone", the height at which most human breathing takes place (4 to 6 ft or 1 to 1.8 m above the finished floor). Toxic gases that are typically monitored in the breathing zone are carbon monoxide, nitrogen dioxide, CO2 (for IAQ monitoring), oxygen, etc.)

That being said, there are a number of toxic gases that are heavier than air, like chlorine, ozone, fluorine, and sulphur dioxide that should be detected near the floor.

Similarly, there are toxic gases that are lighter than air, like ammonia that should be detected on or near the ceiling.

Note: Some applications may require the sensor to be mounted at a different height than indicated.

If you have any questions, contact us.