What happens if the concentration of a substance is below the LEL?

When the concentration of a substance is below the Lower Explosive Limit (LEL), it indicates that there is not enough of the substance present in the air to create a flammable mixture. This means that even in the presence of an ignition source, the mixture cannot ignite or explode because the fuel-to-air ratio is insufficient.

The LEL is a specific concentration range below which a gas or vapor will not ignite or explode, as it lacks the necessary concentration of combustible material. Therefore, any ignition would not lead to an explosion since the conditions required for combustion are not met.

In contrast, if the concentration is above the LEL, combined with an ignition source, an explosion could occur. Thus, understanding the significance of the LEL is crucial for maintaining safety in environments where flammable substances are present.