The filtered LEL sensor provides enhanced resistance to airborne sensor poisons such as high concentrations of hydrogen sulphide gas and volatile silicone vapours. Due to the physical size of some molecules, the filtered LEL sensor is not suitable for the detection of some compounds including complex hydrocarbons, alcohols, ketones and esters. The filtered LEL sensor is suitable for the detection of less complex molecules including C1 to C6 hydrocarbons, hydrogen and acetylene.
For applications requiring the detection of complex compounds, select a detector with a non-filtered version. The non-filtered version also has limitations and is not recommended for combustible liquids with flash points of 37.8°C (100°F) and higher. Consult the following chart for assistance in selecting a suitable combustible sensor: