If a gas has an LEL of 2% and the combustible gas indicator reads 50% LEL, what is the actual gas percentage in the atmosphere?

To find the actual percentage of the gas in the atmosphere when the combustible gas indicator reads 50% of the Lower Explosive Limit (LEL), you need to understand the relationship between the LEL value and the gas percentage.

The LEL is the minimum concentration of a gas or vapor in air that can ignite (also known as the lower flammability limit). In this scenario, the LEL of the gas is 2%. This means that at 2% concentration of this gas in the air, it will just begin to become ignitable.

When the combustible gas indicator reads 50% of the LEL, it's indicating that the gas concentration in the atmosphere is half of the threshold required for ignition. Calculating 50% of the LEL provides the actual volume of the gas present:

50% of 2% is calculated as follows:

0.50 x 2% = 1%.

This means that the actual percentage of the gas in the atmosphere is 1%. Understanding this concept is crucial for making safe assessments in the field, as it helps technicians determine whether the concentration of combustible gases poses a significant risk for ignition.