What does lel mean on a gas detector
LEL means Lower Explosive Limit, which is a technical term for combustible gases. The lowest concentration of a combustible gas that will explode in air in the presence of an open flame is called the Lower Explosive Limit (LEL). English: Lower Explosive Limit.
Combustible gas concentration in the air to reach its lower explosive limit value, the place of gas environment explosion hazard is 100 percent, that is, 100 percent LEL If the combustible gas content only reached the lower explosive limit of ten percent of the place of gas environment at this time the explosion hazard is 10 percent LEL; monitoring of ambient air in the gas, gas environment is often given directly to the degree of danger, that is, the gas in the air content and its lower explosive limit of the percentage to say: “% LEL”; so, this monitoring is sometimes called “explosion detection”, the monitoring instrument used is also known as the “explosion detector “. Specific indicators are as follows:
If the use of combustible gas detector, the combustible gas concentration of the object under test is less than or equal to the lower explosive limit of 20% (volume ratio, the same below).
If other means of chemical analysis is used, when the lower explosive limit of the measured gas or vapor is greater than or equal to 10%, its concentration should be less than 1%; when the lower explosive limit is less than 10% and greater than or equal to 4%, its concentration should be less than 0.5%; when the lower explosive limit is less than 4% and greater than or equal to 1%, its concentration should be less than 0.2%. If there are more than two kinds of mixed combustible gases, the lower limit of explosion shall prevail.
The lowest level of combustible gas that can cause an explosion is called the Lower Explosion-Level (LEL).
LEL it is not a unit, refers to a numerical value, generally refers to the volume of explosive gases in the air than the value of the LEL is not detected by the instrument, it is the national standard for different gases have different values. The data displayed by the gas detection instrument only indicates the concentration of combustible gases in the air, in order to do the alarm. General quantitative analysis of the instrument is marked on the detection of what gas. If it is a qualitative analyzer, then it can not show what kind of gas.
Combustible gas detector category alarm point
The measuring range of our combustible gas detector is 0-100%LEL.
Fixed combustible gas detector is usually equipped with two alarm points (related to the model of the alarm main unit): 10% LEL for the first alarm, 25% LEL for the second alarm.
Portable Combustible Gas Detectors usually have one alarm point: 25% LEL.
For example, the lower explosive limit of methane is 5% by volume, that is to say, this 5% by volume, one hundred equal parts, so that 5% by volume corresponds to 100% LEL, that is to say, when the value of the detector reaches the alarm point of 10% LEL, which is equivalent to the content of methane at this time is 0.5% by volume. When the detector value reaches the 25% LEL alarm point, it corresponds to the methane content of 1.25% by volume.
Therefore, you do not have to worry about the alarm is not always dangerous, at this time is prompting you to immediately take appropriate measures, such as opening the exhaust fan or cut off some of the valves, etc., from the real danger of explosion there is still a big gap between the lower limit, which will play a role in the alarm prompt!
