@farmerman,
Quote:3 temperture thresholds of 1500-1800 degrees achieved by the fires F were certainly enough to weaken steel beams beyond their structural integrity. This easily initiated the gravity collpse.
As Thomas Eager of MIT has stated, "However, it is highly unlikely that the steel at the WTC experienced temperatures above the 750–800°C range. [1,382F to 1,472F]
Let's run with those numbers, quoted above.
The Cardigton fire test performed, described below, illustrates that farmerman's notion that " fires ... were certainly enough to weaken steel beams beyond their structural integrity" is fatuous.
"In the mid-1990s British Steel and the Building Research Establishment performed a series of six experiments at Cardington to investigate the behavior of steel frame buildings. These experiments were conducted in a simulated, eight-story building.
Secondary steel beams were not protected. Despite the temperature of the steel beams reaching 800-900° C (1,500-1,700° F) in three of the tests (well above the traditionally assumed critical temperature of 600° C (1,100° F), no collapse was observed in any of the six experiments."
Quote from the FEMA report (Appendix A).
http://911research.wtc7.net/mirrors/guardian2/wtc/how-hot.htm