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Posted By Michael Carr
HI all
I was wondering if someone could explain to me in layman's ters waht a BLEVE is??
Many thanks
mike
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Posted By Michael Carr
sorry about the typos....by the way!
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Posted By clairel
BLEVE = Boiling Liquid Expanding Vapour Explosion.
How much detail do you want in your layman's explanation?
Just the fact that it is an explosion and fireball from an LPG vessel or the more detailed explanation of heat, liquid and pressure?
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Posted By Swis
I’ve just googled for this and came up all the religious sites. So hands up. Not a specialist in religion.
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Posted By 99|Cadok|99
Boiling liquid expanding vapour Explosion (BLEVE)
This is where a tank such as a LPG tank is involved in a fire the liquid inside the tank is heated up causing the tank to vent the gas. This will continue until the liquid drops to level where it no longer cools the tank. At this point the tank fails resulting in an extremely impressive explosion.
Iain T
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Posted By Michael Carr
Thanks Iain that's the layman's terms I was after
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Posted By Dave Wilson
A number of years ago 15 plus one of these exploded in the south of France and killed about 140 people if memory serves me well.
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Posted By Richard Altoft
Not limited to LPG can in fact also happen with non flammable liquids incl water when steam causes an explosion if pipes or tanks are over heated in a fire. Usual terminology then is a steam explosion but is still a BLEVE.
R
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Posted By Kate Gibb
David, That was Feyzin in France I think - but was 40 years ago. It resulted from human error, failing to shut the valve at the botto of the sphere causing LPG to leak out. This spread to a nearby road and ignited. The fire under the spheres then caused a huge BLEVE.
The following link explains the Feyzin BLEVE, at has some interesting diagrams: http://shippai.jst.go.jp...Detail?fn=2&id=CC1300001
The key safety requirement is toensure no combustible material is kept around cylinders/vessels (e.g. foliage, rubbish). Then to ensure adequate cooling of any LPG canister or vessel involved in a fire. The fire services are well versed on this! Sometimes a BLEVE is inevitable so best to evacuate to a safe distance - shrapnel can go a long way.
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Posted By TonyB
Michael,
Search under Bleve on youtube and you can see some!
TonyB
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Posted By Messy Shaw
Have a look at these images of a recent fire (within the last fortnight I think)
A video of a tank farm fire in Texas. It vents in 12 seconds and explodes 4 seconds later.
New trousers all round for the fire crews!!
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Posted By Andy Brazier
Just to be clear
A BLEVE typically occurs when there is a fire outside, and particularly under a tank/sphere. The contents of the tank heats up and starts to boil. The pressure builds until the tank fails. You then have hot liquid released to atmospheric pressure. At this stage it is well above its boiling point (because the pressure has reduced). Very rapid boiling causes a very large quantity of vapour to be formed which ignites.
One way to reduce the chances of BLEVE are to ensure a fire cannot occur around the tank. This includes making sure any flammable liquids drain away from the area.
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Posted By Alex.wilkes
A BLEVE involves a sudden release of vapour, containing liquid droplets, owing to the failure of
a storage vessel. This occurs when a pressure vessel containing liquid is heated so that the
metal loses strength and ruptures, typically, as a result of exposure to fire. The failure is
usually in the metal in contact with the vapour phase; the metal in this area heats to a higher temperature because there is no liquid heat sink to keep its temperature from rising rapidly, as
there is where metal contacts a liquid phase.
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Posted By Bob Shillabeer
I tried to post this this morning I'm sure but will try again. If you look on Wikipedia it describes a Bleve as an acronym for boiling liquid expanding vapour explosion which is an explosion when a vehicle containing a ressurised liquid is ruptured. It goes on to describe how the explosion acn occur. Rather than repeating the text here try logging on and having a look.
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Posted By Michael Carr
Thanks all for you help
regarfds
Mike
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Posted By Phillip
When a fluid in a container is held at a high pressure far above its atmospheric boiling point and the container suddenly fails exposing the liquid to atmospheric pressure, the liquid says flipping heck I should not now be a liquid but a gas. This very rapid change from (say) 1 unit volume liquid to several thousand unit volumes causes the blast waves we recognize as an explosion.
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Posted By Steve M Granger
.... like they said, just remember;
the expansion rate between the liquid state and the gaseous one gives and instant fuel surface at a vastly different one to the origional contained liquid state.
Add to this the physics behind temperature, pressure and boiling point relationship.
Stir in a bit of understanding on flash points and spontaneous ignition points, UFL LFL etc etc.
Season well and serve as a study question for SP's. Now I know why I had to learn it!
Steve - 'long since forgotten, but now going to do some CPD on maintaining core skills'.
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Posted By FAH
Hi Michael
The majority of the responses above answer your question.
However, I am curious as to WHY you needed to ask the question - would you enlighten us?
Identifying your need may lead to additional, more focussed responses that you may like to consider.
Frank Hallett
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