Result of a sudden and widespread release of a flammable gas or volatile liquid that is stored under pressure, coupled with immediate ignition. This is distinguished from a jet fire by the shorter duration of the event and the difference in the geometry and shape of the flame. When a pressure vessel containing a flammable gas or volatile liquid ruptures, the first result is the quick dispersion of the flammable material as the high-pressure material rapidly expands to atmospheric pressure. During this expansion, the release will entrain large quantities of air as a result of the process. If the material in the vessel is a volatile liquid, this process will also cause formation of an aerosol with the dispersion of liquid droplets away from the release as a result of the vapor expansion.