What is LEL and what does the reading mean?
A. LEL (lower explosive limit) is the point at which a combustible gas, when mixed with air, has developed the minimum concentration to combust when exposed to an ignition source. LEL is usually stated in % of gas in air (1% = 10,000ppm). The LEL sensor can detect many combustible gases but does not differentiate between them so the reading displayed can be the total concentration of multiple combustible gases if present. The LEL sensor requires oxygen in order to oxidize the combustible gas in order to produce a reading. If the environment is oxygen deficient, LEL readings may not be accurate. LEL sensors are usually factory calibrated to either methane or pentane and the manufacturer of the monitor may include a cross sensitivity multiplier for other combustible gases so the user can accurately calculate the concentration of another combustible gas.
