There is kind of fire behaviour called a BLEVE– Boiling Liquid Expanding Vapor Explosion. A BLEVE is what happens, for instance, when a closed container of flammable liquid is exposed to strong heating. It can be caused by an external source, like a pool of burning liquid around the container, or it can result from a runaway reaction within a drum, cylinder, or tank. The internal pressure builds up more rapidly than it can be vented and the containment fails, often explosively. It is interesting to note from the above link that boiling action of the liquid phase in the container absorbs energy and has a cooling effect, but there may come a point where the vapor pressure rise above the liquid exceeds the capacity of the relief discharge capacity and the vessel fails, discharging liquid and vapor across the burn zone. At minimum, discharge and ignition will lead to a large flare, or if conditions are right, an actual detonation of the fuel/air mix could happen over a relatively large space.
These things often begin with some kind of tank or tanker accident (link updated 6/10/16) resulting in a discharge and ignition of flammable liquid. As responders arrive they find a burning pool under or next to the tank(er). Naturally, firemen and bystanders try to help those who may be hurt. As the minutes tick away and the fire becomes more aggressive and the tank gets hotter, the firefighters get their equipment in place and attempt to cool the tanker and suppress the fire. Suddenly the tank fails and there is a prompt bulk discharge of liquid and vapor yielding a large fireball which may include an explosive shock, flying metal debris and a dangerous heat pulse. It is at this point that the surviving bystanders and responders see the error of their ways.
Containers of flammable liquids rarely explode in a symmetric fashion so the container or its fragments are likely to be sent flying at high velocity, possibly spewing flammable material as it moves. Even a relatively small volume of flammable liquid dispersed explosively can fill a large surrounding space with a fireball.
All chemical plants have their protocols for emergency response. It is important for those in charge to recognize an incipient BLEVE and respond accordingly. But even academic chemists should familiarize themselves with the phenomenon. A fire in the lab engulfing closed containers of flammable solvents is extremely dangerous and very quickly firefighting may become your last earthly act, especially without personal protective equipment. It is easy to under estimate the violence of these things.
Every lab person needs to look inward and decide what their personal limit is for dropping the fire extinguisher and running for the exit. In my sophomore organic labs, the seed I planted in the students mind was this: The main purpose of a fire extinguisher was to fight your way to an exit.
Lamentations on Chemistry 
The most meaningful training I’ve ever recieved since I left grad school was the fire training I took at 3M. The guy from the local fire department lit a 8′ x 8′ pan of heptane floating on water, gave me a fire extinguisher and a unforgettable half-smile that said “Let’s see what you can do”. What I remember the most is the heat of the flames as I got closer, especially on the face.
About the time that I got laid off, there was a trend towards “virtual” fire fighting using some kind of video display,… as the real fires were “too expensive”. Insane. The last couple of paragraphs you wrote are right on. If I were king, I’d make fire training a requirement for a chemistry degree (Chem Eng too).
Water pooled in a burning tank of hydrocarbon from fire hoses or wet foam is the classic do-gooder BLEVE. Hydrostatic head prevents boiling as the medium continues to heat, then WHAMMO! Gasoline in a tanker might barely pull that off. Tankage rupture and flash decompression is a better bet in the latter case.
Thermite demos can be BLEVEs. A terra cotta flower pot with filter paper covering its bottom hole is suspended over a tray of deep sand to catch dripping molten iron. If somebody gets clever and uses wet sand… WHAMMO!
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it was nice of u to share d knowledge and info.
thank u.
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I have a situation where a furnace exploded and was wondering whether or not it could be classified as a BLEVE.
There was incidentally water inside the furnace from a roof leakage which was directly above the raw materials hopper for the furnace. The water was allowed to gather inside the furnace for a period of 7 months when the furnace was not in use.
Half an hour after the furnace was started up (I imagine the temperature to be just around 120oC max), an explosion occurred.
I tend to suggest that the explosion was caused by the rapid expansion of the water vapor inside the furnace. The furnace was built of stacked bricks (not even cemented), so I guess that it would not be stable. The furnace was with some ventilation (exhaust ducting) so the expanding water vapor was not completely contained.
So, is there a possibility that the exhaust ducting offered minimum ventilation and thus, BLEVE could still occur?
Thanks!
I had ssuch an explosion happen in my house i had an aersol can of paint and get punctured by my heaters pilot , when i looked it ecploded on me . Then set of another explsion were the carbon monixde is in steel vaccum drum to be vented outside . that exploded causing mass damage to my flooring blow out my windows , my skylight on the 3rd floor . the insurance company doesn’t believe me that i small can of paint spray could cause this kind of damage. I currently have a lawyer . I was hoping if you could poosable explain in laymans terms why and how it happened or if you vcould get me in contacted me with somone thank you Michael
Hi Mike,
I had some trouble following the chain of events you described. Perhaps you had a fuel-air explosion. It doesn’t take many cubic feet of space filled with a combustible fuel-air mixture to create a strong shock. It takes about 0.5 lb/ft^2 overpressure to blow out windows and begin to cause blast damage. The blast wave doesn’t have far to go within an interior space to impinge on things that break.
In any event, your attorney should find an expert witness to work on your behalf. You need someone who can show up at your location and who can provide the right credentials face to face. An expert like this may do some calculations and provide some graphics as well as serve as an expert witness if this goes to court. It won’t be cheap. An experienced attorney should be able to find such a person. A guy who writes anonymously on a blog (like me) has approximately zero credibility in these things. Maybe you can find a retired fire marshal to think this through.
Best of luck!