Essay: Disintegration of World Trade Center
The time it took before the building gave in, “56 minutes for WTC 2 and 102 minutes for WTC 1´support that time was needed for the fires to burn to a critical point in order to weaken the fireproofing. The steel burned to a critical temperature whereby it would no longer withstand the “tremendous energy released by the downward movement of the massive top section of the building at and above the fire and impact floors”. Video evidence show that the disintegration started from the top of the building.
There is no evidence to show that any explosions occurred below the positions of impact, which were 82nd floor in WTC2 and 98th floor in the case of WTC1. This was occasioned by the suggestions that there were explosives planted in the building prior to the attacks. Video evidence shows that the collapse started on the hit floors towards the ground floor “until the dust clouds obscured the view”. (Manning (2002) available online). The smoke that was seeing coming out of the windows as the building collapsed was caused by compressed air escaping the rooms because of the collapsing stories. The collapsing stories meant that floors were falling to one another, which led to limited space for air that was already in the building.