1 Crazing of windows, in which hundreds of cracks appear in the glass, indicates rapid heating and means an accelerant was used to start the fire.
REALITY:
Crazing is caused by the rapid cooling of window glass, as when water from a fire hose strikes a hot window.
2 Burn marks on the floor indicate that a fire was purposely set, because heat rises and fire only burns upward. It must have been set by pouring a liquid on the ground and lighting it. REALITY: When a fire reaches flashover—the point at which an entire room ignites—extreme radiant heat will produce burn marks or even burn holes in the floor..
3 Melted metals, such as doorway thresholds, indicate that a liquid fire starter must have been used in order to reach temperatures that exceed their melting points.REALITY: Wood fires, especially those that reach flashover, frequently exceed the melting point of ...
