A) No other steel buildings have collapsed due to fire.
B) The collapse of the WTC buildings due to fire did not look like it should have.
Does no one else see a conflict with these two statements?
100 Million Americans Question Official 911 Story
by sammielee24 217 Replies latest members politics
-
-
notverylikely
That makes as much sense as NISTS theory on building seven.
Well, gravity IS only a theory...
-
-
clearlyenlight
So how deluded can people be on this board? 9-11 was totally an inside job, just start reasearching the subject.
None of the black boxes were found, but they did find a paper passport, go figure.
Not only two buildings fell, but three, building 7 fell 9 hours later demolition style. And this just scratches the surface of the truth of the subject.
And the facts just pile up, come on people it is time to wake up, I am not referring to everyone who has comment of course.
-
Razziel
There is a lot of misinformation on this thread.
I found a short calculation using thermodynamics to calculate the temperature of the fire in the WTC (haven't looked at the rest of the site, so I cannot say I support don't support the conclusions drawn.)
http://911research.wtc7.net/mirrors/guardian2/wtc/how-hot.htm
That calculation shows the fire couldn't have gotten any hotter than 450F in ideal circumstances. In reality it would have been much less.
As I pointed out earlier, the open-air burning temperature of jet fuel is 550F, so after the initial explosion, the fire isn't going to get any hotter than 550F. It doesn't matter how much fuel there is, the temperature will never get hotter thant this point at standard atmospheric pressure. If you have the idea that the fire just kept getting hotter and hotter until the steel melted, it's incorrect.
This is the reason some people suggest (probably wrongly) that thermite may have been involved. It is one of few materials that can actually burn hot enough at atmospheric pressure to achieve a temperature to melt steel.
Back to my pov, steel expands with increasing temperature. Since the joints and connectors are riveted and welded into place and for all intents and purposes cannot move, the expansion causes stress directly proportional to increasing temperature. If at any point, the combined stress from loadbearing and thermal expansion exceeds the yield stress of the steel quality, it can fail. If the temperature is hot enough, the yield strength of the steel is lessened, even a thousand degrees before the temperature is actually hot enough to melt it. At 550F, the yield strength would not be greatly impacted however.
In cases where human life is threatened if failure occurs, most engineering standards require a minimum safety factor of 3. This means that whatever the maximum specifications are, the design has to be able to withstand at least 3X the max requirements before failure. Even with redundant supports, if the structural damage was severe from the jet crashes, the increased stress on any undamaged supports may have increased many fold beyond 3x.
The thermal deformation from increased stress due to temperature may literally been the straw that broke the camels back, just enough to push the combined stress over the tipping point for systemic failure.
BTW, if the original engineers neglected to calculate the effect of a fire when modeling the damage from a plane crash, they probably made the incorrect assumption that the fire insulation would still be present and functioning on the steel beams. It's purpose was to allow a few hours for the fire department to stop any fires before any major thermal stress could occur.
-
Razziel
Edit to my post: At 550F, the yield stress of steel would not be greatly impacted, but thermal stress would still be significant.
-
AllTimeJeff
*sticking head in cracked door*
Yeah, nothings changed. Imagine that?
PS: I apologize that this thread has amused me. If I were Catholic, I would confess and ask for absolution.
-
notverylikely
As I pointed out earlier, the open-air burning temperature of jet fuel is 550F, so after the initial explosion, the fire isn't going to get any hotter than 550F. It doesn't matter how much fuel there is, the temperature will never get hotter thant this point at standard atmospheric pressure. If you have the idea that the fire just kept getting hotter and hotter until the steel melted, it's incorrect.
That wasn't the only thing burning.
-
Razziel
"That wasn't the only thing burning."
I addressed this in my first post on this thread. Most materials at 1 ATM burn in a narrow temperature range.
-
notverylikely
I addressed this in my first post on this thread. Most materials at 1 ATM burn in a narrow temperature range.
Well, most materials people are familiar with burning. With regards to the air pressure, it's not so much the air pressure as it is the amount of oxygen provided. That's why blowing on a fire with your breath will dramatically increase the temperature of a fire. Using a bellows on a stangard wood oak fire can get the temp up to almost 2000 degrees.The fire would have been using all the air on the floors that were burning and air would have been flooding in from other areas, almost creating a bellows. You can create the exact same effect yourself with a pizza over or a hole in the ground.
There was aluminum in the building that, if burning with other materials, would also raise the temp. The idea of "paper burns between 450 - and 500 so that's how hot the fire was" is a simplistic and incomplete model.