JP-5 and JP-8 are military fuels and are specially formulated to have a higher flash point for safety reasons. Commercial jet fuel in the U.S. is called JetA and has a lower flashpoint. The flash point for JP-5, for example, is 60 degrees celcius or 140 degrees farenheit. The flash point for Jet A is 38 degrees celcius, or 100.4 farenheit.
http://www.usor.com/pdfs/msds/fuels/Jet_Fuel_MSDS.pdf
Flash point is 38C, autoignition over 200 C, and the vapor concentration in air must be between .7% and 5%. Higher than 5%, no ignition (too rich).