NYCEMT86
Graduate Poster
- Joined
- Jul 14, 2007
- Messages
- 1,091
1000 degrees? I'll accept that. But for a short period of time, you must admit that.
What short time? ---- ETA - Ignore that question, misread your first statement.
Typically, it can be short, but it also can be sustained through burning fires. If you are talking about one room in one small area of the building, then yes I could agree that it would be very unlikely that that would have caused the collapse of WTC7, but that isn't the case in this situation. We are looking at several areas throughout the entire building being effected for several hours.
Fires are very stubborn things, and they simply refuse to burn when the fuel source has been consumed. And the fuel source in the upper floors of WTC7 was office contents - desks, chairs, carpet, paper.
Which are all synthetics that tend to have a lower flame point and have a higher amount of energy release. We aren't taking about one room, but several floors and offices, which are packed full of these things.
And brief periods of 1000 degree F heat is not sufficient to compromise the massive steel beams to failure mode. Again I call your attention to the properties of steel, which wicks heat away from the fire and dissipates it all directions through out the structure.
That is simply untrue, while steel does conduct heat away, it uniformly heats up at the same time. Conduction does not create a cooling effect at all in a burning fire. When steel is heated to certain temperatures it gradually reduces its strength, but not only that it expands. At a 1000 degrees F you are looking at a significant amount of strength loss. (there was chart that showed exactly what percentage was lost, but I can't seem to find it right now)
Many other much hotter and longer burning high rise fires have not resulted in the catastrophic collapse as WTC7.
Though true, one can not compare one steel structure to another and have that be universal. There are more variables that introduced with WTC7 than compared to the Madrid fire or your neighbors house, which include but are not limited to type construction and fire load.
Sorry I can't post some of my tasty comparison photos, but I'm a newbie
If you have a link, that would be nice.
ETA - Typos and missing information. Lack of sleep is bad for the brain.
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