Some more indications that BLEVE events do occur with non-pressurized vessels full of liquids (not pressurized liquids).
http://www.fireworld.com/ifw_articles/boat_valves.php
http://gaussling.wordpress.com/2007/04/29/bleve-boiling-liquid-expanding-vapor-explosion/
This one seems to be mainly modeling, prediction, and response to a BLEVE event, but if you search, you'll find BLEVE modeling scenarios involving very large storage tanks for ethanol and gasoline.
http://www.aqmd.gov/ceqa/documents/2001/nonaqmd/mobil/final/ch4_f.doc
This appears to be a fire facts sheet from Alberta, Canada's, municipal affairs office.
http://www.municipalaffairs.gov.ab.ca/fco/docs/Flammable_liquid.doc
DOT Hazard Classifications, category 3.
http://ci.redding.ca.us/solwaste/hwclass.htm
And this. Holy crap, 160 pages of liquid and gasseous hazards are charted out, and they're not even talking about chili night at my house...
http://www.risoe.dk/rispubl/SYS/syspdf/ris-r-1504.pdf
Search it using BLEVE as your search term. Interesting reading.
Yes, I realize how long it would take to boil 1.5 million gallons of product in a tank. It can take awhile.
Ever hear of a boiling pool fire?
That's a fire where a large quantity of flammable material has gathered in a pool -- on the ground, in a moat, whatever -- and the heat of the material burning on top causes everything beneath it to boil.
This does two things...
It greatly intensifies the heat of the fire, and it also makes it one hell of a lot harder to put out to the point where the material can maintain enough residual heat that it simply keeps self igniting.
Interestingly enough, one of the places where boiling pool fires are seen are places where there are large quantities of liquid fuels...
Like tank farms.
Rupture one tank and set the contents to blaze, and you can have a fire that is simply too large to be contained quickly and easily.
In other words, a fire that, if the liquid surrounds or abuts an adjacent storage tank, can provide more than enough heat to cause a BLEVE explosion.
Tank farm fires, whether at an oil refinery, a petrochemical facility, or a end user storage facility, are scary scary ****.
About 20 years ago when I was a volunteer fire fighter I had some experience with a boiling liquid pool fire. About 300 gallons of diesel fuel were set alight in a large open pan; the fuel was about 8 inches deep.
We left it burn for about 20 minutes, at which time it started to boil, and things got REALLY interesting. It was hot before, but when that diesel started to boil it felt like someone turned on a blow torch full blast and aimed it at us.
We tried extinguishing the fire with a large dry chemical extinquisher mounted in our rescue truck. We'd knock it down, put it out, and within 2 to 3 minutes it would reignite because the metal in the pan was super heated. That happend 4 or 5 times. We were trying to use up the chemical in the extinguisher (it held about 750 pounds) because it had to be recharged.
When we decided that we were ready to get serious, we set up two high volume foam hoses and the dry chemical extinguisher. It still took us another 10 minutes to get that tank of oil out to the point where it wouldn't reignite.
That was just a very small, very contained pool fire. Large pool fires can be almost impossible to fight effectively.
"
but most vents ARE sized properly
Properly sized for what?
Vents currently aren't sized with an eye towards releasing the pressure generated by a catastrophic fire.
If they were sized to provide absolute protection against a BLEVE situation, then they would be far larger than they already are.
Some have proposed in the past to include blow out panels in storage tanks that would take over where the tank vents fail. As far as I know, that's never been adopted/mandated at a national level.
"Not that he has but he appears to find it highly unlikely as do I and alot of other people."
A lot of people thought that 19 Muslims highjacking 4 airliners in a coordinated fashion would be unlikely, as well.
It's always unlikely.
Until it happens.
And then you're ****ed.