Whether and how easily any object (everything, including floors) catches fire, and for how many rounds it will keep burning, is defined in each tile's properties and can therefore be modified by a map's author. -> Notice that the wooden watch tower in Normandy burns down completely once ignited. The problem with this is that, once the "burn time" is over, the object is destroyed. - That's why some things are set not to burn. There should be a "minimum burning time" on every object which does NOT destroy it, to simulate the ammo's napalm fire itself.