what does lel mean on a gas monitor?

LEL in gas detector actually refers to the concentration value of gas alarm.

The low content of combustible gas that can cause explosion is called the Low Explosion-Level(LEL).

LEL it is not a unit, it refers to a numerical value, generally refers to the volume ratio of explosive gas in the air. The value of LEL is not detected by instruments, but it has different values for different gases in national standards. The data displayed by the gas detector only indicates the concentration of combustible gas in the air for alarm. Generally, quantitative analysis instruments are marked with what gases are detected. If it is a qualitative analysis instrument, it can’t show what kind of gas it is.

When the concentration of combustible gas in the air reaches its lower explosion limit, we call the explosion risk of combustible gas environment in this place 100%, that is, 100%LEL. If the combustible gas content only reaches 10% of its lower explosion limit, we call the explosion risk of combustible gas environment in this place as 10%LEL; The monitoring of combustible gas in the ambient air often directly gives the environmental risk of combustible gas, that is, the percentage of the combustible gas content in the air and its lower explosion limit: [%LEL]

That is to say, when the detector value reaches the “100%LEL” alarm point, it is equivalent to the methane content of “5%” by volume. When the value of combustible gas detector reaches the “25%LEL” alarm point, it is equivalent to the methane content of “1.25%” by volume. However, you don’t have to worry about whether the combustible gas detector will be in danger at any time after giving an alarm, and it is still a certain distance from the explosion. Take corresponding measures immediately, such as turning on the exhaust fan or cutting off some valves or turning on the spray system, so that the danger of explosion will not appear. There is still a big gap from the lower explosion limit where there is a real possibility of danger, so as to give an alarm, which will play the role of alarm prompt.