Flammable Limits

Within any likely flammable mixture there are mixture levels which do not support combustion. The lower flammable limit is the lower volume of gas or vapour in an air mixture, which cannot support combustion. The lower limit, which, just, does not support combustion, is known as the Lower Flammable Limit (LFL). Similarly, there is an upper flammable level, which does not support combustion. There comes a point in a flammable mixture where there is too much gas or vapour in an air mixture, which provides insufficient oxygen to support combustion. This is known as the Upper Flammable Limit (UFL).

Summary