Nowadays, we can see gas detectors everywhere in industries such as petrochemicals, chemical manufacturing, pharmaceutical microbiology, etc. Whether it is detecting gas concentration, gas composition

 or detecting gas micro leaks, a useful gas detector can provide a safe environment for our production and life. However, when we use gas detectors in our daily lives, the detection range on the LCD label of the gas detector often appears with words like 0-100LEL. Do you know what gas detector LEL means?

The LEL in gas detectors actually refers to the concentration value of gas alarms.

The low content of combustible gases that can cause explosions is called the Low Explosion Level (LEL).

LEL is not a unit, it refers to a numerical value, generally referring to the volume ratio of explosive gases in 

the air. The value of LEL is not detected by instruments, it is a national standard that has different values for 

different gases. The data displayed by the gas detection instrument only indicates the concentration of 

combustible gases in the air for alarm purposes. Generally, quantitative analysis instruments have markings 

indicating what gas is being detected. If it is a qualitative analysis instrument, it cannot display what kind of 

gas it is.

When the concentration of combustible gases in the air reaches its lower explosive limit, we call the explosive 

hazard level of the combustible gas environment in this place 100%, that is, 100% LEL. If the combustible gas 

content only reaches 10% of its lower explosive limit, we call the explosive hazard level of the combustible gas

 environment in this location 10% LEL; The monitoring of combustible gases in the ambient air often directly 

provides the hazard level of the combustible gas environment, which is expressed as the percentage of the 

combustible gas content in the air and its lower explosive limit: [%LEL]

That is to say, when the detector value reaches the "100% LEL" alarm point, it is equivalent to a methane 

content of "5%" by volume at this time. When the value of the combustible gas detector reaches the "25% 

LEL" alarm point, it is equivalent to a methane content of "1.25%" by volume at this time. However, you 

don't have to worry about whether there will be danger at any time after the combustible gas detector 

alarms, as it is still some distance away from reaching an explosion. Take corresponding measures 

immediately, such as opening the exhaust fan, cutting off some valves, or opening the sprinkler system, so 

that the danger of explosion will not occur. There is still a long way to go before the lower explosive limit 

that may pose a real danger can be alerted, so as to serve as an alarm prompt.