[roger-roger]

Zipperfish Zipperfish:

Eisensapper Eisensapper:

For someone who knows how to blow up a building, and the effort that would have to go into a demolition of that kind that would take down the WTC. It is MUCH more plausible to say that jet fuel, which burns at an extremely high temperature, would be enough to weaken a steel structure already under severe strain. Besides the impact of a plane hitting the building would set off any planted charges factions of a second after it impacted. The blast wave would start at the area of impact and blow up as well as down. The explosive train you are talking about does not support the video evidence.

I've been wondering about this. Jet fuel, despite the fancy name, is basically a diesel-like oil with very high quality control and fancy additives (if, as I suspect, the jets used what is called "Jet A" in Canada). So it doesn't burn at "extremely high temperatures" in an open environment (one source cited about 600 deg F). The 9/11 consiracy theorists use this argument often--that the jet fuel could not burn hot enough to significantly deform structural steel. However, they (mostly) neglect to consider that the temperature at which jet fuel burns in an open environment is only part of the equation. Heat of combustion is measured in joules/mole, not in degrees of temperatures. In an open environment, you can roughly relate the heat of combustion to the temperature, but in an insulated environment with turbulent conditions you can easily get much higher temperatures. The adiabatic flame temperature for diesel (I think this would classify as the theoretical maximum temeprature) is probably around 2000 deg C.

With respect to WTC 7, there really shouldn't have been jet fuel in any significant amounts anyway (although there would have been a lot of chemcially-similar diesel fuel, for generators and such. One site indicated that the ASTM test for fire endurance for four hours. Seeing as how the WTC fire burned uncontrolled for much longer, perhaps this is the reason for failure.

Source: http://www.doctorfire.com/flametmp.html

Anyway, it's a little disconcerting to think that a 47-storey building collapse because of structural steel deformation from a normal fire.

I'm quite wrong.

Did the insulation played a part in raising the temperature to levels enough to weaken the steel? I think the fire supression system failed as well didn't it?

[Zipperfish]

Eisensapper Eisensapper:

Zipperfish Zipperfish:

Eisensapper Eisensapper:

For someone who knows how to blow up a building, and the effort that would have to go into a demolition of that kind that would take down the WTC. It is MUCH more plausible to say that jet fuel, which burns at an extremely high temperature, would be enough to weaken a steel structure already under severe strain. Besides the impact of a plane hitting the building would set off any planted charges factions of a second after it impacted. The blast wave would start at the area of impact and blow up as well as down. The explosive train you are talking about does not support the video evidence.

I've been wondering about this. Jet fuel, despite the fancy name, is basically a diesel-like oil with very high quality control and fancy additives (if, as I suspect, the jets used what is called "Jet A" in Canada). So it doesn't burn at "extremely high temperatures" in an open environment (one source cited about 600 deg F). The 9/11 consiracy theorists use this argument often--that the jet fuel could not burn hot enough to significantly deform structural steel. However, they (mostly) neglect to consider that the temperature at which jet fuel burns in an open environment is only part of the equation. Heat of combustion is measured in joules/mole, not in degrees of temperatures. In an open environment, you can roughly relate the heat of combustion to the temperature, but in an insulated environment with turbulent conditions you can easily get much higher temperatures. The adiabatic flame temperature for diesel (I think this would classify as the theoretical maximum temeprature) is probably around 2000 deg C.

With respect to WTC 7, there really shouldn't have been jet fuel in any significant amounts anyway (although there would have been a lot of chemcially-similar diesel fuel, for generators and such. One site indicated that the ASTM test for fire endurance for four hours. Seeing as how the WTC fire burned uncontrolled for much longer, perhaps this is the reason for failure.

Source: http://www.doctorfire.com/flametmp.html

Anyway, it's a little disconcerting to think that a 47-storey building collapse because of structural steel deformation from a normal fire.

I'm quite wrong.

Did the insulation played a part in raising the temperature to levels enough to weaken the steel? I think the fire supression system failed as well didn't it?

Insulation would play a part, becasue it would conserve heat inside a room. The hotter the room, the less energy the flame would lose to its surrounding through heat transfer, adn teh more closely it would appraoch its adiabtic flame temperature. Also, turbulence would create hot-pockets (as well as cool pockets for that matter!) where there were areas of optimal fuel/oxygen mixtures at favourable pressures and temperatures. I think, anyways. I don't think you were wrong at all. I was just filling in more of the thermodymaics end of things. I actually know thermo quite well and spouting off about it makes me feel important.

[roger-roger]

Zipperfish Zipperfish:

Insulation would play a part, becasue it would conserve heat inside a room. The hotter the room, the less energy the flame would lose to its surrounding through heat transfer, adn teh more closely it would appraoch its adiabtic flame temperature. Also, turbulence would create hot-pockets (as well as cool pockets for that matter!) where there were areas of optimal fuel/oxygen mixtures at favourable pressures and temperatures. I think, anyways. I don't think you were wrong at all. I was just filling in more of the thermodymaics end of things. I actually know thermo quite well and spouting off about it makes me feel important.

Hehe I am the same way about demolitions

[Blue_Nose]

Eisensapper Eisensapper:

Did the insulation played a part in raising the temperature to levels enough to weaken the steel?

As I mentioned before, it was the floor system that failed first, causing the collapse. The temperature due to the fires was the cause, but it wasn't most significantly through "weakening" the material properties of the columns.

The floor system was concrete overtop corrugated steel - as the steel expanded in the heat, the entire floor systems expanded and failed, leaving the vertical columns without lateral support.

If the floor support failed at only one level, that means the column is now unsupported over twice the length, and that will cause it to buckle at 1/4 the load it would have sustained otherwise. Loss of support in three consecutive levels would reduce the column to 1/16th its strength. With multiple floors suffering loss of lateral support, the columns would be unable to sustain the loads that were required.

On top of that, any deformation of the column away from being perfectly vertical and straight will also significantly affect its capacity. If the floors' expansions cause the columns to bend out of line, they'll buckle at a lower load.

That's all before considering the effects of the extreme temperature on the material strength of the steel columns themselves.

(I'd also like to point out in regard to the 'rep' I received today that it wasn't hurley_108 that I 'eviscerated' in this thread - he actually argued the same thing)

[Tricks]

Heavy_Metal Heavy_Metal:

granted the physics of the 9/11 'attack' and the empire state building were different, but you must also take into account the WTC was BUILT WITH SPECIFICATIONS TO WITHSTAND A DIRECT HIT FROM A PLANE....who's ignoring the facts now?

I wonder how they tested it. Oh and it was also built 30 years before it was hit. Aircraft change.

$1:

enjoy the read and the videos....
http://www.abodia.com/911/eReports/Why% ... 0short.doc

that's ONE example on forign soil...

enjoy the video
http://www.prisonplanet.com/articles/no ... harges.htm

http://www.prisonplanet.com/032404firef ... scuss.html
- you want to contradict eye wittness reports?

http://www.prisonplanet.com/articles/no ... hstood.htm
and finally look up the video loose change explains alot....

Sweet jesus. Go read the 9/11 foiler thread, all 100 pages of it. All of this has been done.