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seanw1461) I followed up on the old safety features of the World Trade Center. Sprinklers were the only feature that stood out from a fire safety video by the New York and New Jersey Port Authority for the World Trade Center (made 1996). https://www.youtube.com/watch?v=aBM9-y8gfHo. However the fire was much too large for them to put out, and may have even made it worse because water, when in contact with molten aluminum explodes.
2) Next I looked into why and how the World Trade Center (WTC) collapse happened. The WTC did not have concrete core or outer. Most high-rise buildings have one or the other as concrete is not subject to fire. The WTC steel trusses and columns were fireproofed with spray foam which fell off the building on impact with the airplane. The crash through the building resulted in flammable debris getting pushed to the far walls and corners, the most vulnerable location, and fatally weakening the WTC’s steel core. NIST report never stated that the fire melted the steel beams, steel melts at 2750 degrees F, but looses half its strength at 1100 F. Parts of the WTC fires reached 1800 F on that day. With the weakening, the trusses began to sag, bowing inward causing all of the weight to rest on the perimeter columns which could not bear the load and eventually snapped. After the first floor fell, the “pan-caking” effect resulted in each floor collapsing the one beneath it.
3) Lastly I looked at the new disaster prevention features of One World Trade Center. The key features which the Twin Towers were lacking are: a concrete core with stairwells located in center, larger than required staircases, and a separate first responder stairwell. Many experts believe if the WTC had a concrete core, they would not have fallen.