Tuesday, January 19, 2010
Reader Comment – 1-19-10 Gasoline 3
A Reader, Red Team (certainly reference to a security professional that simulates being part of a terrorist team penetrating facility defenses), joined an earlier discussion about gasoline storage facilities and vapor cloud explosions. He makes two separate points in the discussion. First Red Team writes: “I've done some ‘Red Team’ work for a few security firms that contract with DHS. Many of these above ground gasoline storage tanks have floating roofs. I do not know the technical name. Considering this, there is very limited gasoline fumes of which to ignite. Attacking a large gasoline tank with a VBIED, satchel charge or stand-off weapon would not create a large catastrophic explosion because the fumes are not present in large quantities. This belief, for the most part, is pure Hollywood.” Red Team is correct; fuel storage facilities use some sort of technique, floating tops (that’s probably not the correct terminology) that move up and down with the liquid level or displacing the oxygen in the headspace with some inert gas. They have done a lot of work to prevent even small vapor cloud explosions in their tanks. Even if you were able to get a tank ignited it would just blaze away at the surface, providing a rather spectacular display of flames and smoke. It will just keep burning until the gasoline is consumed or fire fighters manage to get a good foam blanket on the surface. Modern tanks are kept far enough apart that a tank fire in one probably won’t set off a neighbor. No, to get a good VCE you have to spill the gasoline on the ground leave it alone long enough for a vapor cloud to form. There should be very little wind to disperse the cloud and the ignition source should be above the surface of the big puddle. Even the getting enough surface area in many tank farms may be a problem because the secondary containment may be sized to keep the surface area of a spill small enough to prevent the formation of a vapor cloud. Not wanting to make this a primer on turning a gasoline tank into a VCE, I won’t go into details, but you have to make a large enough spill with a large enough surface area in the right weather conditions to make a VCE. Breaching a containment dike or causing a catastrophic failure of a tank would both contribute to the success of the endeavor. This is not a task for an underwear bomber. It will take at least one fuel system engineer and some people with a talent for explosives, but it can certainly be done. This brings us to the second part of Red Team’s comment: “However, considering the fact that many organization attack to cause death, destruction, fear and adverse economic reactions, attacking a gasoline facility might cause spillage and fire, but not a large explosion. The results could greatly increase the cost of oil because of the perceived effects of the terrorist act.” Because of the socio-economic (I get extra points with a former college professor for writing that) nature of gasoline an unsuccessful attack (no VCE) can still be counted as a successful strike. First the fire is spectacular and gets wide spread press coverage for hours, even without a terrorist claim of responsibility. Next gasoline is inextricably linked with an icon of American culture, the automobile. Politically, the jihadist can always claim that the gasoline was stolen from Muslims, so it is theirs to destroy. Finally an attack that significantly damages part of the gasoline distribution network will have economic affects, at least locally. Win, win, win, and win; all for a ‘failed’ attack. The effect is significantly magnified if accompanied by a VCE fireball.