Boiling liquid expanding vapor explosion flammable liquids

Avoid direct sunshine on containment surfaces in hot climates. Direct spills of flammable materials away from pressurized storage vessels to reduce the risk of a boiling liquid expanding vapor explosion (BLEVE). 

Additional events of concern that may or may not involve flammable or combustible materials are condensed-phase explosions, uncontrolled chemical reactions, boiling liquid expanding vapor explosions (BLEVEs),... 

BLEVE (Boiling Liquid Expanding Vapor Explosion) A blast resulting from the sudden release and nearly instantaneous vaporization of a liquid under greater-than-atmospheric pressure at a temperature above its atmospheric boiling point. The material may be flammable or nonflammable. A BLEVE is often accompanied by a fireball if the contained liquid is flammable and its release results from vessel failure. 

Daniel A. Crowl, Ph.D. Professor of Chemical Engineering, Michigan Technological University Fellow, American Institute of Chemical Engineers (Section Editor, Process Safety Introduction, Combustion and Flammability Hazards, Gas Explosions, Vapor Cloud Explosions, Boiling-Liquid Expanding-Vapor Explosions)... 

A Latin American chemical plant experienced a catastrophic fire and series of Boiling Liquid Expanding Vapor Explosions (BLEVEs) that resulted in the loss of one life and 5 million in direct damages (1977 dollars). The initial vapor cloud occurred as a maintenance mechanic started to remove a pneumatic actuator from the liquid discharge line below a tank of flashing flammable liquid that had a boiling point of 7° F (—14° C). 

A boiling liquid-expanding vapor explosion occurs when a pressure vessel containing a liquid is heated to a temperature liigh enough to cause tlie metal to lose strength and rupture. The source of tlie heat is normally another fire near tlie vessel. The effects of a BLEVE depend on whether tlie liquid in die vessel is flanunable. If the liquid is flammable, it may eitlier cause a fire, which radiates heat, or fonii a vapor cloud, which could result in a second explosion. 

A boiling-liquid expanding-vapor explosion (BLEVE) can occur if a container of liquid or liquified gas at temperatures above their atmospheric-pressure boiling points were to rupture. Sudden loss of containment and reduction in pressure can result in explosive vaporization of some of the liquid, and the sudden increase in volume can propel parts of the container to great distances and create blast effects (pressure and impulse). Eurther, if the superheated liquid or liquified gas is flammable, a fireball involving the ejected vapor, aerosol, and liquid can result, particularly if the cause of the overpressure and rupture is exposure to fire. 

Incident Outcome The physical manifestation of the incident for toxic materials, the incident outcome is a toxic release, while for flammable materials, the incident outcome could be a boiling liquid expanding vapor explosion (BLEVE), flash fire, vapor cloud explosion (VCE), etc. For example, the incident ontcome for a leak of chlorine from a railcar is a toxic release. 

This section addresses a special case of a catastrophic rupture of a pressure vessel. A boiling liquid expanding vapor explosion (BLEVE) occurs when there is a sudden loss of containment of a pressure vessel containing a superheated liquid or liquified gas. This section describes the methods used to calculate the effects of the vessel rupture and the fireball that results if the released liquid is flammable and is ignited. 

BLEVE (Boiling Liquid Expanding Vapor Explosion) with superheated liquid (flammable or nonflammable) (see next section). 

Fire is more likely tlian an explosion where tliere is a loss of contaimnent of a flammable material from a railroad car, barge, ship lank, or from a pipeline. However, both uiiconfiiicd vapor cloud explosions (UVCES) and boiling liquid-expanding vapor e. plosions (BLEVES) can occur as a result of transport accidents, (sec Section 7.5)... 

Boiling Uquid expanding vapor explosion is an explosion that occurs when a liquid stored above its boiUng point is released into the atmosphere. Such a release immediately causes a shock wave if the Uquid is flammable, it can create a VCE. Example A propane tank ruptures during a fire and causes a BLEVE followed by a VCE. 

An important hazard in the process industry is the boiling liquid expanding vapour explosion (BLEVE). This is understood to be the explosively rapid vaporization and corresponding release of energy of a liquid, flammable or otherwise, upon its sudden release from containment under greater-than-atmospheric pressure at a temperature above its atmospheric boiling point [37]. It is a physical explosion which is a consequence of sudden pressure relief. If a flammable material is involved a chemical explosion or a fireball can follow. 

If a flammable liquid is in a closed container, the vapor pressure will increase inside the container as the temperature of the liquid increases. This increase in temperature can come from many different sources. Increases in ambient temperature, radiant heat from the sun, or a nearby fire can increase the vapor pressure in a container. As the pressure increases in a container, it will reach the setting on the pressure-relief valve and the relief valve will function. If this pressure increase occurs in a container that does not have a relief valve, the container may rupture. Rupture may also occur in a container with a relief valve if the pressure rises too fast for the relief valve to vent the material into the air, or if the relief valve is not working properly. In either case, the rupture may be violent, with a fireball and flying pieces of tank that can travel over a mile from the blast site. This phenomenon is referred to as a boiling liquid expanding vapor explosion (BLEVE). 

One of the more disastrous problems that can occur with flammable liquids is a boiling liquid expanding vapor explosion, BLEVE. These are caused by rapid pressure buildup in closed containers of flammable liquids heated by an external source. The explosion occurs when the pressure buildup is sufficient to break the eontainer walls. 

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