Question

When we say that Methane has an LEL of 5% we mean that

There should be at least 5% air in the methane air mixture for it to be explosive
There should be at least 5% methane in the methane air mixture for it to be explosive
At least 5% oxygen is required for the Methane air mixture to be explosive.

Answer 1

Explanation:

we use methane (CH4) as an example, the LEL (lower explosive level) of methane is generally considered to be 5% by volume (5% bv). That means the mixture is too lean to burn if there is less than 5% methane present. But at 5%, we can burn or explode if there is an ignition source.