TABLE OF CONTENTS BLEVE means "boiling liquid expanding vapor explosion" and is a rather unsatisfactory term for the sudden rupture of a vessel or system containing liquefied flammable gas (or flammable liquid held at pressure at a temperature above its atmospheric-pressure boiling point) due to fire impingement. The results are:
a pressure blast due to the release of pressurized material in the vessel or system,
missiles due to projected fragments of the vessel or system, and
a fireball resulting from intense combustion of the turbulent mixture of escaped flammable vapor and liquid with the air.
Typically, the sequence of events is as follows:
A pressurized vessel of a liquefied flammable gas (such as an LPG stock tank) is exposed to fire.
The vessel is heated by the fire. The pressure in the vessel rises as the contents are heated. Eventually the pressure relief valve operates, releasing the vapor evolved by the heat input to the vessel. The vapor is ignited by the fire and burns with a fierce, luminous, and highly radiant flame, but this flame may not cause any adverse effect of itself. The pressure is held at the relief valve set point.
The level of liquid in the tank falls as vapor escapes. Either because of flame impingement on the upper part of the tank above the internal liquid level, or because the level of liquid falls to below the level of the exterior flame, part of the vessel shell becomes overheated as a result of the...
