Buncefield fuel depot Explosion 1

[ColourfulFigsnDiags]

Can't seem to find any other posts about this (amazingly enough) ... MASSIVE blast at Buncefield fuel depot near Hemel Hempstead North of London in England.

"The man in charge of investigating the massive fires at a Hertfordshire oil depot on Sunday says the flames may have destroyed all clues to the cause.
Deputy Prime Minister John Prescott has visited the scene of the blasts which injured 43 people, two seriously.

The fire chief described the incident at the Buncefield fuel depot near Hemel Hempstead, after 0600 GMT, as possibly the largest in peacetime Europe. " ...
more here:

http://news.bbc.co.uk/2/hi/uk_news/4517962.stm

Plume can be seen on satelite images eg the plume is the brown smudge in this MODIS image from 11:50Z 11/12/2005

http://www.waw.net.au/gallery/v/wz/Ref-expl-11-12-05-1150Z-250m-crop_001.jpg.html

Comments from anyone in England?



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[phorth]

The explosion woke me and rattled the windows of my house in London, about 40 miles away.

I have no information about the details so this is pure speculation, but I would think that this needs to be a vapour cloud explosion to be so powerful. That means a release of volatile vapour, and mixing with air, before ignition. I can't see how this scenario could arise in a tank farm with floating roof tanks, without pressurised storage, as I understand it. A wild guess would be that one of the products was over spec on vapour pressure and this caused one of the tank roofs to sink, and allowed vapour to form a cloud above the tank. But there is no evidence yet available that I know of. We wait with interest.

 

[owg]

I agree with the comments by phorth. There is an eye-witness account from "10 minutes walk" from the site. The house windows were blown in then the drapes were sucked out. The building seemed to expand then contract. About 0.7 psi is needed to blow out the windows and do minor structural damage. Estimating 10 minutes walk at 3500 feet, and estimating the maximum blast from a 3 MMIG gasoline tank vapour space explosion, 0.7 psi would occur only 800 feet from the source. This is based on reports that 20 "petrol" tanks were on fire, each being 3 million imperial gallon (85,000 bbl) tanks. There is some window breakage and damage to ceilings at 0.3 psi but that low end number would occur only 1500 feet away from the source.

HAZOP at

http://www.curryhydrocarbons.ca

 

[jmw]

Drllernic has posted in thread483-142200 and the link he posts contains many images and evidence of some wuite sever damage at some distance from the site.
Phorth and OWG appear to have evidence for their postulated nature of the blast amply provided there.

JMW

http://www.ViscoAnalyser.com

 

[IFRs]

In the USA, floating roof tanks are required to have large vents in the tank shell and/or tank roof. These vents (among other things) normally allow vapors above the floating roof to become diluted as air flows into and out of the tank from wind and other effects. The air/vapor mixture exits the tank and wafts away. In Europe, many internal floating roof tanks are not equipped with free vents in order to reduce emisions from the tanks, especially those that are relatively inactive. This may have allowed the air/vapor mixture inside the tank to become rich with combustible vapors and when the tank was filled that mixture exited the tank forming a cloud, became less rich, became explosive and found an ignition source.

 

[stookeyfpe]

It appears that most of the tanks are constructed as open floating roofs.

The following link provides some additional photos that are quite spectacular.

http://www.herts.police.uk/

 

[JStephen]

Notice in one of those photos you can see several fixed-roof tanks off to the right.

 

[ColourfulFigsnDiags]

A few more sat shots from today and yesterdays subsets (couldn't be bothered digging out the raw images)

Click images for larger res versions

Yesterday




Today




Thanks to MODIS Rapid Response system for the images

http://rapidfire.sci.gsfc.nasa.gov/

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[Guidoo]

Look also at:

http://www.total.gb.com/media/mediatool.cfm?page=3

The tanks involved in the fire are most of the tanks in HOSL west (most of which are fixed roof) plus the big one in the lower left hand corner of the picture owned by British Pipeline Association (also fixed roof) plus one of the three other bigger tanks owned by BPA (also fixed roof).