Considerations Regarding Fire:

1) In order for structural steel to literally melt and change state into a flowing liquid, its internal temperature (as opposed to the surrounding temperature) must be raised to 1538ËšC (2800ËšF).

2) The strength of steel is correlated to its internal temperature at a given moment. While internal temperature will gradually rise during prolonged exposure to constant high temperature. If the temperature stabilizes, the steel will not continue to weaken as a cumulative effect. As its temperature changes — either up or down — its strength also changes accordingly.

3) At high internal temperatures below the melting point, steel can lose its load bearing strength and rigidity and become subject to bending, sagging, etc. Much well documented testing has been done over the years to determine these temperatures in order to predict the behavior of steel structures in intense fire scenarios. To summarize the significant consensus of these tests, the strength of steel is reduced to 20% of normal when it reaches an internal temperature of around 720ËšC (1328ËšF).

This is significant because, as mentioned, standard building design specifications require that structures be able to bear five times their maximum theoretical load (20% = 1/5). This means that even if all the steel in a building reached an internal temp of 720ËšC, the building would still be able to carry its maximum load. Since maximum theoretical loads rarely occur, the steel temperature in a typical situation could probably go significantly higher before failure would occur.

1) One of the first explanations was put forward by the American Society of Civil Engineers in an article titled "Why Did the World Trade Center Collapse? — A Simple Analysis", by Zdenek Bazant and Yong Zhou. Their theory depends on the simultaneous failure of the majority of the columns on a given floor, which they say would allow the upper part of the building to fall freely onto the lower part, thus allegedly triggering a sequence of events that would "doom" the entire tower. They acknowledge that this "triggering" condition would require more than half of the column steel on a given floor to reach temperatures exceeding 800˚C (1472˚F), but they fail to distinguish between fire temperature and internal steel temperature and offer no explanation for how this could possibly occur.

http://www-math.mit.edu/~bazant/WTC/

An obvious fallacy with theories of this type is that column strength and heat conductivity were NOT segmented by the vertical spacing of the office floors. Load-bearing strength was vertically continuous over many "floors" for any given region of the building. The columns in the core structure were specially fabricated to be multiple stories in height and were joined together by welded connections. Dense cross-bracing between columns created a monolithic entity that was structurally independent of the office floor attachment locations. Heat produced by burning material on a particular office floor would also be vertically dissipated over a multi-story region of the building. It really makes no sense to talk about about column behavior on a "given floor". The columns didn't have "floors".

We've already seen that high internal steel temperatures are very difficult to achieve over a large area in a large structure. Not only is Bazant and Zhou's so-called triggering condition clearly impossible given the test data presented earlier, but the results of the examination of steel recovered from the fire zones, as reported by NIST in 8/04, showed no evidence of temperatures over 625ËšC (1157ËšF) and only rare instances of temperatures over 250ËšC (482ËšF)! This is consistent with the international fire test results mentioned earlier.

From TrueMemes.com - too many points to reproduce here, if you're interested look at the site.

So are these lies or do the points tend to refute Tom's idea of "doughnuts on a broomstick" as well as ER's "air draft furnace burning" theory?