Re: London "Bombs"

Islander wrote:
Jean Smith wrote:
I've glad to see the ineptitude continues. Hopefully, their fingerprints are all over the cars the cans and arrests will be made before the perps figure out what they need to have an explosion. Searching Google Groups on this subject brings up lots of speculation, such as, the smoke in the first car being fuel vapor (which could explain the intoxication), and lots of skepticism and derision. If they had a good fire going in spilled gas, would the propane spilled from the pressure relief valves put the fire out by driving out whatever oxygen had not already been consumed?

My first reaction to this when I heard the news was disbelief at the hysteria in the news media. Sure, it might produce one heck of a fire ball, but would the nails, etc., produce a shrapnel-like effect? I doubt it.

As far as explosive capability, gasoline ranks up there pretty high, but it needs to be vaporized and mixed with oxygen. Otherwise, it just burns. Propane has less energy content. If the fire provided by the gasoline caused the tanks to rupture, it would produce a fireball, but not much more. More likely, the pressure relief valves would vent, producing some flame, but not an explosion unless the temperature got high enough to cause the tanks to rupture. In any case, it would not be expected to product the same explosive effect of more conventional explosives.

I wouldn't want to bet on the heavier propane extinguishing a fire, however!



There was a segment on CNN this morning where they duplicated the propane/gasoline car bomb in an isolated area. They taped hex nuts to the propane tanks to simulate the nails used in the British devices (they explained that they didn't want to spread nails around the area for fear of causing flat tires).

I'll have to say that the explosion was spectacular! Quite a large fireball which also consumed a plywood structure erected next to the Jeep Cherokee used in the demonstration. While they emphasized the damage that might have resulted from the explosion, I didn't see much evidence. The rear lift gate was blown off and one of the doors was blown open. Otherwise, there were no holes evident in the *** metal from projectiles and the reporter picked up one of the hex nuts a few yards away from the vehicle (while describing how someone could have been injured -- a bit of an exaggeration, IMV). One of the propane cylinders ruptured and was found about 150 feet away, not surprising since a compressed gas container might well tend to be propelled by the gas once the container is compromised.

Make no mistake, this kind of car bomb is dangerous, primarily because of the fire ball. However, it would be wrong to equate this to the much more dangerous devices built of nitrate based, dynamite based, or other high explosive material.

I would conclude that this may be an indication that more dangerous explosives are getting more difficult for these groups to obtain. If so, that would be good news.
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