Diesel fuel fires did not play a role in the collapse of WTC 7.
Sure but they do contribute to the building being not completely dead typical like truther raving idiots insist. That was the point. Truthers lie like crazy before they even begin suggesting alternative theories. That's usually how the conspiracies theories nonsense goes, try to cast doubt on stuff and then hope everyone will swallow down the first load of bullshit they see instead.
And the structural damage sustained from the debris of WTC 1s collapse had little effect in compromising the integrity of WTC 7. The debris caused some damage to the southwest region of the building -severing seven exterior columns- but this structural damage did not initiate the collapse. The fires ignited by the debris, rather than the structural damage that resulted from the impacts, initiated the buildings collapse after the fires grew and spread to the northeast region after several hours. Furthermore, the debris impact caused no damage to the spray-applied fire resistive material that was applied to the steel columns, girders, and beams except in the immediate vicinity of the severed columns. This is all from NISTs final report, NCSTAR 1A.
Actually, they simply don't know how much damage the building really took because we don't have photos nor reliable eyewitness accounts of all areas likely to have been impacted.
There is no evidence that the electric substation contributed to the collapse or fires in WTC 7.
No but once more, not a normal building, and it could easily have contributed to easing its ability to fall down on top of its self once the collapse began.
Buildings do not collapse through the path of greatest resistance. And unless all of its supporting columns experienced sudden and global failure, this uniform collapse at free fall speed is a complete phenomena.
You might recall a rather large area of the building was on fire, and when vertical girders buckle over a considerable height a pancaking effect is exactly what you'd expect. What force would exist to knock the building on its side? Gravity pulls down, and down only, and the collapse should only accelerate as the collapsing load increases in mass and gains energy. That is the path of least resistance, any other direction requires a massive force to deflect the force of gravity. The building would only fall over on its side if the failure occurred across a angled cross section of the building that would act as a pivot point that was meanwhile strong enough not to crush. That might be able to happen in some fire cases, it didn't happen here. As for complete phenomena... yeah I think you can say that about the entire day. No many other cases of millions of tons buildings falling down after being hit by 125 ton missiles to look at you know.
NISTs working hypothesis for how WTC 7 tower collapsed was an arcane domino effect, initiated by the displacement of a not particularly important column, a displacement which was driven by thermal expansion of adjacent floor beams.
Most steel buildings are designed so no one column is that important, but they also don't design them to burn with zero fire fighting for unlimited periods. In fact one of the major points the NIST report made was that the building's fire resistance was never evaluated as a complete unit. Each piece was evaluated independently so the whole thing may have been flawed from the get go. It also may simply have been built wrong, which is entirely possible given say, the example of the the I-35W bridge collapse, caused by key structural plates being half the required thickness. Is this likely, no, is it more likely then any conspiracies theories, fuck yes.
We need to understand is just how far columns 79 would have to be pushed for it to walk off its seat. NIST reported that column at girder 79 was 11 inchs wide (the seat, that is) and therefore, the girder would have to be pushed at least half of that distance, or 5.5 inchs, to walk off its seat. 5.5 inchs was needed to move the vertical web of the girder, and therefore, the center of mass of the girder, off the seat. Thermal expansion is a function of temperature, therefore, we need to know what temperature NIST said the beams reached, then we can estimate how much it expanded. This was a tricky question for NIST, because at temperatures of 600 degrees celsius, steel will loose strength and stiffness and therefore won't be able to expand into the girder.
Yeah, and it wouldn't need to expand into the girder at that point, at 600 degrees celsius steel will loose most of its strength precisely because its getting soft, and at that point the floors are going to fail anyway as the beams sag.
There is an unrealistically large chain of improbable events that would have to happen to dislodge column 79 from its position, and yet another unrealistically large chain of improbable events that would have to happen for its failure to culminate in tower 7s destruction. The official story is refuted even by their own biased research and investigation. I think its high time you use that vaunted occams razor of yours to slit your wrists with.
You want to reject the report completely, I really don't give a fuck, but lets go with that. Then what happened? I saw those events on live TV myself, a million plus people saw the fucking attacks face to face. That is factual history. The exact details of one buildings collapse don't need to be proven to make this a fact either. Claiming anything else happened, well you'd better offer up a different theory and some evidence to back it up. Truthers always think that if you can somehow cast doubt on a specific explanation it makes any other random far more exotic explanations with zero evidence what so ever more credible. Life doesn't work like that.