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Bjørn

Sun Jan 13 2008, 02:45PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

If so can you find some reliable details about this story?

An 89-year-old man was killed by an exploding Christmas tree, police in the north German city of Bremen said on Friday.

Police said resin seeping from the branches ignited when the dried-out tree caught fire, triggering Wednesday's explosion. The shock wave killed the pensioner and blew out all the windows of the house where he lived.

The blast caused damage of 100 000 euros.

Firnagzen

Mon Jan 14 2008, 02:42AM

Registered Member #567 Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147

Uhhh...

Sounds like fake to me. I would say burn, yes, plenty of evidence for that, but explosion, no. Maybe a gas explosion in conjunction with the tree?

Coronafix

Tue Jan 15 2008, 07:45AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Yeh, sounds a bit fishy to me, but that said, eucalyptus trees here in Australia are known to
explode in fire situations, spawning new fires sometimes up to a mile from the fire front.

Bjørn

Tue Jan 15 2008, 03:50PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

The two main questions to be asked is:
1. Is there enough energy in a christmas tree to cause a significant explosion? Yes, 10-20 MJ/kg.

2. Can it be released quickly enough to cause an explosion? Yes, for example by incomplete combustion that converts the wood to CO and H2 gas.

The news story suggests that something else strange happened, it does not really sound very credible.

Marko

Tue Jan 15 2008, 04:07PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

2. Can it be released quickly enough to cause an explosion? Yes, for example by incomplete combustion that converts the wood to CO and H2 gas.

Large amounts of flammable gases can be produced by dry distillation of wood, but in order for that the oxygen would have to be depleted and no fuel-air mix could form before fire just self extinguishes.

Generating significant amounts of flammable gas only seems possible to me by use of an external heat source.

Large trees can be blown by steam in forest fires, but small trees like this will hardly give anything but some crackling even if fresh.

Considering I never anywhere seen evidence of small trees and logs exploding with significant force I don't think that is very credible. Even more unintuitive things like flour probably make much better fuel air explosives.

Bjørn

Tue Jan 15 2008, 06:10PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Wood-burning stoves causes explosions from time to time that can kill several people so it should be possible in a small room to get something similar to happen.

Imagine some small fire at floor level that for some reason generates a lot of CO2 (or the CO2 can have a completely different source). That will cause oxygen to rise and increase the production of combustible gasses that also rises out of reach of the fire. Then at the perfect moment someone opens the a door.

Electroholic

Wed Jan 16 2008, 12:17AM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

yea, if the christmas lights get it hot and dry enough, i suppose it would start vaporizing the resin/waxy kinda stuff form the wood.

Firnagzen

Wed Jan 16 2008, 12:17AM

Registered Member #567 Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147

Explosion, I still don't think so. Where does the containment come from?

Bjorn, that does happen. It's called... Can't really remember. Blowback? But I don't think that's an explosion.

Ps. We should send this one to Mythbusters. Speaking of which, they proved (fairly definitively, in my opinion) that Christmas lights alone don't set trees alight, though overloaded plugs might.

ragnar

Wed Jan 16 2008, 12:46AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

wrote ...
Imagine some small fire at floor level that for some reason generates a lot of CO2 (or the CO2 can have a completely different source). That will cause oxygen to rise and increase the production of combustible gasses that also rises out of reach of the fire. Then at the perfect moment someone opens the a door.

Firnagzen wrote ...

Bjorn, that does happen. It's called... Can't really remember. Blowback? But I don't think that's an explosion.

Backdraught / backdraft.

Bjørn

Wed Jan 16 2008, 02:38AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

I have been in the room next to a wood stove that blew the top off with a big bang so I would call it an explosion. A wood stove is designed to nok behave like a bomb so most disasters are caused by people that add other things than wood (you know who you are). Only in very special conditions do violent explosions happen when burning pure wood.

I don't believe that a christmas tree exploded but I would like to know more details just in case something interesting did happened.

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