#wtc7

First of all, have fun, its over 700 pages. fuk u for making me read half of it and then skim the rest (all tho it was totally within my power to not get so invested in this ask)The Full NIST report only JUST came out, rly, literally last year and it primarily settles on multiple fires going on for almost 8 hours with a failed extinguishing system leading to a support column failing after multiple floors around it collapsed, bringing the whole thing into the shell of the building.

so, this is footage of the street level just 15 minutes after the collapse of WTC2

Take note of the two causeways, familiarize yourself with the scale at the ground. the dark band conceal a mechanical floor, thats the 5th and 6th floor. after the collapse of wtc1 basically floors 13 and below become so obscured with debris and smoke that the full extent of the damage can’t be seen.

However, while most of the debris completely flattened parts of WTC6 into craters, a substantial amount landed in the street while large portions of the facade from WTC1 flew across the street, at least hitting the base of building 7 or notable portions of the facade above that, as seen here:

you can see the WTC1 debris as it lay on Vesey Street here as well as the condition of the promenade walkway (large tree covered walkway on the western side of WTC7), starting at 4:42

To the right of the promenade above, a several storey pile of debris begins.

Included below is the aftermath of WTC1′s collapse and Building 7, take care to note WTC 6′s direct hole damage from the peeling off north face of WTC1, the same peeling facade that ultimately strikes Building 7

based off of the damage shown in video evidence as well as available footage until the collapse at 5:21, i have drawn a visual model of building 7′s south (WTC1 facing) side:

ignore the cratered WTC6 on the lower left lol, i primarily wanted to show the elevated promenade and covered walkway connecting to the building on the 3rd floor. it is also on the 3rd floor where the main lobby is, which houses the security desk that the FDNY fire command station was established.

So first, i drew the observable damage including the massive gash that was observed from the roof to the bottom

After the collapse, it is clear the same peeled section of WTC1 that cratered WTC6 also collapsed onto the promenade, carving an H-shaped hole into the southwest corner of wtc7 from floors 5 to 17. This hole likely cut several metres into the building at it’s deepest, visible from the elevators inside the building. The debris piled ontop of the promenade was judged to be “40 feet tall” from an on-site firefighter.

Now, following this, fires began. after a while, the fires spread to the north and east face of the building, where it was observed either flickering behind the windows or outright bursting out the window and shooting flames out.

If fire were seen burning through to these sides of the building, that meant the fire likely engulfed the entire floor. So the floors 7, 8, 9, 12, and 13 were at least totally engulfed. The following is my illustration showing the south, east and also north side (The west side isn’t really shown aside from where fire was seen in the hole. Floors 7-8 on the west generally understood to show fire or have smoke rising out of broken out windows).

Red is where fire was observed to burst through the window before building 7′s collapse. Orange is where fire was at least observed within the building. Yellow is where fire or smoke was present based on the above. This is the summation of all visible fire and not it at it’s most intense.

Unfortunately, because of the smoke rising from WTC1′s ruin and Building 7 itself, along with very limited amount of documentation of these portions of the building before it’s collapse, the south side’s state of fire is unknown. So i overlayed green to show where no one could see on account of terrible visibility or other buildings obscuring it.

We can assume that the fires on the south at least mirrored the intensity of the north’s By 10:30 am (around half an hour after WTC 1′s collapse) the building was deemed completely evacuated. The Fire Command Station on floor 3 was vacated completed also, as they moved it following WTC 2′s collapse.

Once chaos following the demise of the twin towers was brought under control over an hour later, attention was again brought to WTC7 as FDNY dudes on scene reported that

a large amount of debris from WTC 1 had crashed through the front center (south side) of WTC 7 from approximately the 10th floor down to ground level, and debris ripped off part of the southwest corner from approximately the 8th floor up to the 18th floor.  The collapse of WTC 1 also was ascribed as responsible for starting fires inside of WTC 7.

The fires on the south side was observed around the 7th floor, around the “10th to 14th floor” and an additional one as high as the “20s or 30s”

During this time, firefighters ponder the relation of diesel fuel tanks in these lower floors to the fire.

At 1pm, a group of police and firefighters entered the building from the east, reporting:

At the 5th floor, they moved to the A stairway and proceeded up.  On the 8th or 9th floor, one of the group said he saw two elevator cars ejected from their shafts and in the hallway.  Looking past the elevators, they could see a gaping hole in the south face from around the 6th to the 9th floors.  They could see one floor below and two to three floors above that location.  A lot of the core walls were destroyed, and one individual reported that he saw columns hanging from the floor above.

By 2pm, a Chief Officer reported fires on floors “6, 7, 8, 17, 21, and 30″By 2:30, the decision was made to pull all operations out of Building 7.

Based from these reports, i can assume the observable fires on the south side appeared to burn until collapse as such:

Anyway, the whole report goes to contrast other building fires, why they didnt collapse and went on to point out a crucial structural weakness in the building, namely the way floor beams are welded laterally to a few specific ones, which would be susceptible to the localized fires on the first floors (remember how it was the top floor penthouse on the east side of the building that buckled inward first?)

And how the fire would have travelled across the floor as it burned through office cubicles and accompanying furniture over the next several hours, intensifying as it moves

In the east of the building, several floors would be hot (up to 700°C) enough for the lateral girders to bow and eventually fall away, with predictive models pointing to the collapse beginning on the 13th floor, leading to the eastern portion of the floors to collapse down ontop of eachother all the way down several more floors.

One column in particular (column 79), is now left hot and noodling around, allowing it to buckle and collapse into the internal heat chasm too, resulting in the vertical progression of failure of the floor systems up to the roof level across the entire east side of WTC 7, taking down the rest of the building in short order soon after. This is why you see the rooftop penthouse fold in half before being the first thing to disappear ahead of the total collapse.

Why? columns 79, 80, and 81 (the later soon giving after 79 from displacement) were the primary load bearers in the eastern portion of Building 7. The descent of column 79 literally pulls the building down into the footprint of it’s own shell.

and the funny thing? the gaping hole in the west face of the building, the massive gash from top to bottom as well as the fuel tanks played little or no part in determining the collapse, only in starting the fires that ripped around the building.

So from the south, it probably looked like this in those first seconds of collapse shortly after the disappearance of the eastern half of the penthouse into the shell

aaand from the north again:

anyway, i fucking wasted several hours of my precious time i could’ve spent making MSprats to do this effortpost instead, so fuck my life