Tom Murphy wrote:
If you think steel can't be affected by fire, why do you think they spray fireproofing onto steel trusses in the first place?

At 10:29 a.m., WTC 1 (the north tower) collapsed and contrary to the claims of 9/11 conspiracy people, it did not collapse into its footprint like a controlled explosion. (See the diagram) Instead, as the building collapsed, the debris from WTC 1 spilled into the surrounding streets and onto WTC 7 among others, damaging the building. (See the diagram to the left showing the debris in black which extended north beyond WTC 6).

Eyewitness accounts from firemen such as Captain Chris Boyle and Deputy Chief Peter Hayden and photographic evidence back this up. It is the south side of WTC 7 that was damaged and it is likely that the fires (see figures 5-16 and 5-17) started as a result of debris from the collapse of WTC 1, the fires in WTC 7 started at approximately the same time as the collapse of WTC 1 and it is the fires that are primarily the reason the WTC 7 building collapsed. Most 9/11 conspiracy people only show you the east side and north side of the WTC 7.