19/06/2020
Copied from NFPA (National Fire Protection Association Organization) Safety Regulation
Spontaneous ignition, on the other hand, involves a substance self-heating to a point where it ignites, without the need for any outside ignition source like a flame. Hand sanitizer is not subject to self-heating and would require temperatures to reach over 700 degrees Fahrenheit to spontaneously ignite, according to Guy Colonna, director of Technical Services at NFPA.
"Spontaneous ignition would be an ignition source independent of a flame or a spark, [and] it requires a material that is reactive to do what's called self-heat," Colonna says in a new video interview on the topic (above). "Internally, it undergoes a reaction and changes its properties, and when changing its properties, it releases lots of heat energy. Hand sanitizer, the alcohol [in it], is a material not inclined to do that. ... The ignition temperature of the alcohols are going to be something in excess of 700 degrees Fahrenheit."
In other words, while hand sanitizer gives off ignitable vapors at roughly room temperature or above, that vapor-air mixture still needs to be exposed to very high temperatures to ignite. A flame can do it. A hot car can't.
