It is unfortunate that, no hard and fast rules exist for installing gas detectors since there are a number of variables that have to be considered. Ultimately, it is the customer who has to evaluate conditions at the facility in order to make this decision.
Guidelines for Installing Gas Sensors
- The vapor density or relative weight of gases: Sensors should be placed near the floor for vapors or gases three or four times heavier than air. For the detection of lighter than air gases, sensors should be fitted near the roof or ceiling.
- Ignition sources: Gas detectors have to be placed between a source of ignition and a potential leak source, if possible nearer to potential leak sources.
- Air currents: Generally, it is advisable to place the gas sensor where the existing air currents consist of the maximum concentration of the gas being monitored.
- Dispersion of gas: Usually, gas detectors should not be kept far from any potential source of escaping gas. Especially for liquids of low volatility, the gas sensor has to be located in the immediate area of the vapor source. Liquids with slow rates of dispersion or high flash points may generate a low reading if the gas sensor is at any distance from the break or spill.
- Temperature limitations: Since all gas detectors have ambient temperature restrictions, the installation of the gas sensor should be within the specified range.
- Vibration: Vibration should be considered while selecting the gas sensor location as it is capable of damaging the detector. Generally, this means anchoring the detector to a firm base or wall instead of anchoring it to a motor housing.
- Wiring: Good instrument wiring practices should be integrated in the gas sensor installation and this wiring should be kept separate from other AC wiring.
- Accessibility: Gas sensors have to be installed in a location allowing reasonable access, as it is desirable to calibrate periodically.
- Moisture protection: Sensors must be mounted where they are safe from direct contact or immersion in water.
- Dust protection: It is mandatory to use sensor dust covers if the gas sensors are mounted in dusty or dirty environments.
This information has been sourced, reviewed and adapted from materials provided by MSA - The Safety Company.
For more information on this source, please visit MSA - The Safety Company.