The fire point of a fuel is the lowest temperature at which the vapour of that fuel will continue to burn for at least 6 seconds after ignition by an open flame of standard dimension. At the flash point, a lower temperature, a substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire. Most tables of material properties will only list material flash points. Although in general the fire points can be assumed to be about 10 °C higher than the flash points, although this is no substitute for testing if the fire point is safety critical.
Testing of the fire point is done by open cup apparatus.