@pemile

Pour le WTC7 c’était un building très spécial au niveau des locataires...
De grosses réserves d’hydrocarbures pour l’alimentation auxiliaire de certaines agences.
Ça a pris plus de temps.. Plus d’une vingtaine de témoignages — essentiellement de pompiers — exposent que, vers 16 heures, l’évacuation du bâtiment fut ordonnée par crainte d’un effondrement.

After the North Tower collapsed, some firefighters entered 7 World Trade Center to search the building. They attempted to extinguish small pockets of fire, but low water pressure hindered their efforts.[34] Over the course of the day, fires burned out of control on several floors of 7 World Trade Center, the flames visible on the east side of the building.[35] During the afternoon, the fire was also seen on floors 6–10, 13–14, 19–22, and 29–30.[31]:24 (PDF p. 28) In particular, the fires on floors 7 through 9 and 11 through 13 continued to burn out of control during the afternoon.[7] At approximately 2:00 pm, firefighters noticed a bulge in the southwest corner of 7 World Trade Center between the 10th and 13th floors, a sign that the building was unstable and might collapse.[36] During the afternoon, firefighters also heard creaking sounds coming from the building.[37] Around 3:30 pm, FDNY Chief Daniel A. Nigro decided to halt rescue operations, surface removal, and searches along the surface of the debris near 7 World Trade Center and evacuate the area due to concerns for the safety of personnel.[38] The fire expanded the girders of the building, causing some to lose their structural integrity. This led column number 79, a critical column supporting a large part of the 13th floor, to buckle, causing the floors above it to collapse to the fifth floor ; however, this could not be seen from outside the building. The structure also developed cracks in the facade just before the entire building started to fall.[6]:21[39] According to FEMA, this collapse started at 5:20:33 pm EDT when the east mechanical penthouse started crumbling.[5]:23[40] Differing times are given as to what time the building completely collapsed :[40] at 5:21:10 pm EDT according to FEMA,[5]:23 and at 5:20:52 pm EDT according to NIST.[6]:19, 21, 50–51 There were no casualties associated with the collapse.[39] NIST found no evidence to support conspiracy theories such as the collapse being the result of explosives ; it found that a combination of factors including physical damage, fire, and the building’s unusual construction set off a chain-reaction collapse.[41]