What does the Lower Explosive Limit (LEL) indicate?

The Lower Explosive Limit (LEL) indicates the lowest concentration of a vapor in the air that can ignite and cause an explosion when an ignition source is present. This value is crucial in assessing the safety of environments where flammable substances are present, as it provides a threshold below which the mixture is too lean to support combustion.

Understanding LEL is essential in hazardous material management and safety practices because concentrations below this limit do not pose an explosion hazard, while those above it can create a significant risk. The LEL is typically expressed as a percentage of gas or vapor in air, allowing safety professionals to evaluate and mitigate risks associated with flammable substances effectively. In contrast, the other options relate to different concepts of combustion or flammability but do not accurately describe the LEL.