Fires
BLEVEs can be caused by an external fire near the storage vessel causing heating of the contents and pressure build-up. While tanks are often designed to withstand great pressure, constant heating can cause the metal to weaken and eventually fail. If the tank is being heated in an area where there is no liquid, it may rupture faster without the liquid to absorb the heat. Gas containers are usually equipped with relief valves that vent off excess pressure, but the tank can still fail if the pressure is not released at the correct rate. Relief valves are sized to release pressure fast enough to prevent the pressure from increasing beyond the strength of the vessel, but not so fast as to be the cause of an explosion. An appropriately sized relief valve will allow the liquid inside to boil slowly, maintaining a constant pressure in the vessel until all the liquid has boiled and the vessel empties.
If the substance involved is flammable, it is likely that the resulting cloud of the substance will ignite after the BLEVE has occurred, forming a fireball and possibly a fuel-air explosion, also termed a vapor cloud explosion (VCE). If the materials are toxic, a large area will be contaminated.
Read more about this topic: Boiling Liquid Expanding Vapor Explosion
Famous quotes containing the word fires:
“Every year without knowing it I have passed the day
When the last fires will wave to me”
—William Stanley Merwin (b. 1927)
“The lumberers rarely trouble themselves to put out their fires, such is the dampness of the primitive forest; and this is one cause, no doubt, of the frequent fires in Maine, of which we hear so much on smoky days in Massachusetts.”
—Henry David Thoreau (1817–1862)