Explain lower flammable limit LFL and upper flammable limit

Explain lower flammable limit (LFL) and upper flammable limit (LFL) of a combustible material. Assume gasoline to be $5 wt% iso-octane and 13 wt% n-heptane. At room temperature and 1 atm pressure, the air above a pool of gasoline will become saturated (you can assume gasoline to be an ideal mixture). Is the air-gasoline mixture within its flammable limits? In what condition will the air-gasoline mixture be above UFL? Is there any explosion risk m this case?

Solution

LOL is the volume per cent which is lower end of theach concentraction range over which a flammable mixture of gas or vapour in air can be ignited and UFL is the limit beyond which gas is not ignitable and this is the maximum concentration of the inflatable object.