The fire point of a substance differs from the flash point in that it is a lower temperature and ignites briefly, but cannot sustain the fire. At the flash point, the combustion sieges immediately when the flame or external ignition source is removed. At the fire point, the combustion sustains at least for 5 seconds after the flame is removed. The flash point is significantly lower than the fire point by usually 8 to 10 percent. The flash point and fire point should not be confused with the auto-ignition temperature of a liquid, which is the temperature at which the liquid ignites spontaneously without any external ignition source such as a flame or a spark.