What does the lower flammable limit represent?

The lower flammable limit, often referred to as the lower explosive limit (LEL), signifies the minimum concentration of flammable vapors in air that is necessary for combustion to occur. For combustion to happen, there needs to be a specific amount of fuel present in the air, and this lower limit indicates the threshold below which the mixture is too lean to ignite. When the concentration of flammable vapors is below this limit, there is not enough fuel for a flame to propagate, regardless of the ignition source present. This concept is critical in safety practices, especially in environments where flammable materials are handled, as it helps in assessing the risk of fire or explosion. Understanding this limit is essential for maintaining safe working conditions and preventing accidents.