The flash point of a fuel is the lowest temperature at which it can vaporize to form an ignitable mixture in air. If a source of ignition is given, then it starts burning. If a source of ignition is not given, it remains as a ignitable mixture.

The fire point of a fuel is the temperature at which it will continue to burn for at least 5 seconds after ignition by an open flame.

In general the fire point can be assumed to be about 10 °C higher than the flash point.

The flash point is defined as the fuel temperature at which the equilibrium fuel vapor concentration of its lower flammability limit is attained. In reality the flash point of a chemical is the lowest temperature where enough fluid can evaporate to form a combustible concentration of gas. It is the lowest temperature of oil at which the application of defined test flames causes the vapors above the surface to ignite and the release of vapors at this temperature is not sufficiently rapid to sustain combustion.

The fire point is defined as the lowest fuel temperature at which the diffusion flame is sustained longer than 5 s above the fuel pool without any external heat supply. The fire point for engine oils is usually 20-30 higher than flash point.

http://en.wikipedia.org/wiki/Flash_point

http://en.wikipedia.org/wiki/Fire_point

Flash point is a temp at which vapor of fuel will ignite in form of flash when it come in contact with fire. (flash may last long for 5 sec.)

and fire point is a temp at which vapor of fuel will ignite for long time when it come in contact with fire.

Flash point is the point from which there is a probable chance that flash may occur. Flash is similar phenomena like lightning, it lasts for a small time. Whereas at fire point, one can assume that the substance is surely gonna ignite. At this point in general case, this is the minimum point where there is one of the highest probability of catching fire. These two temperature points hold great importance in transportation and storage industry