For monitoring: 
Carbon dioxide, Hydrocarbons, Methane and jet fuel vapours
 
Key Features
Single sensor
Low power consumption
Dual temperature compensated pyroelectric infrared detectors
Fast response with accurate low-level gas detection
Long sensor life
Water / dust tight / corrosion resistant polycarbonate enclosure
Linear analog (4 - 20 mA) output
 
Description
The AST-I series of analog transmitters are high quality, industrial, dual beam, referenced transmitters with miniature infrared sensors, analog output and water / dust tight, corrosion resistant, non-metallic enclosures..
The AST-ICD detects carbon dioxide (CO2) with a choice of one of three different ranges.
The AST-IHC detects hydrocarbons, methane (CH4) and jet fuel vapours.
Care should be taken to not spray the sensor head in wet environments. The sensor vent opening has a microporous PTFE filter attached which provides splash protection only, it is not designed to provide protection from the application of pressurized water.