What could a lower explosive limit (LEL) indicate about a gas mixture?

A lower explosive limit (LEL) indicates the minimum concentration of a gas or vapor in air that can ignite and produce a flame when exposed to an ignition source. If the concentration of the gas is below the LEL, there is not enough fuel present for combustion to occur, meaning that the mixture is too lean to ignite. Therefore, indicating that it can ignite under certain conditions, when the concentration reaches at least the LEL, suggests the presence of sufficient fuel mixed with air for combustion.

Understanding LEL is critical in hazardous materials response because it informs responders of the potential for an explosive atmosphere. It aids in determining safe operational practices and deciding on evacuation zones or protective measures. Knowing that a gas mixture can ignite if it meets or exceeds the LEL highlights the importance of monitoring concentrations in environments with potential explosive hazards.