Since when does a skyscraper collapse from fire?
A hot enough fire weakens metal. Jet fuel, diesel or heating oil burn very hot. If there is enough fuel to burn for an extended period of time things happen.
What caused the twin towers to collapse? It wasn't the direct hit from the airplanes or the weight of the airplanes on the structure. Without the extended fire from the jet fuel the buildings wouldn't have collapsed.
If you have an extended hot fire at the base of a building it will also cause a structural failure and then there is nothing to hold the building up.
The buildings that collapsed experienced very unique and unusual circumstances.
First of all, the heat would mostly go upwards
Secondly, the fuel would not last for hours, as the wings (which act as fuel containers) can be assumed to be ripped apart, so the fuel is mixed with the air everywhere and therefore would combust within several seconds, minutes at most.
At most, the temperature due to the jet fuel fire would increase by about 200 degrees celsius, which is not even
nearly enough to melt or even weaken steel.
Also, most of the heat would be absorbed by the air in the first place anyway.
by the way, this tower did not collapse:
https://www.youtube.com/watch?v=6hSPFL2Zlpgnote that fireworks in fact do heat up the building much more than jet fuel (at least in those quantities) for the simple fact that the fire is sustained for a much longer period of time. Therefore the air will become much hotter and thus the structure of the building gets more time to absorb the heat, instead of the heat just blowing away with the wind.
WTC steel was tested for 2000 degrees C and the kerosene's open air burning temperature is around 350 degrees C. You can't have a fire that burns at 350 degrees burn something that melts at 2000 degrees.
Bullshit lies: Max adiabatic burn temperature 2,500 K (
2,230 °C) (4,040 °F) Open Air Burn temperature:
1,030 °C (1,890 °F)
Bullshit lies #2: Pure Iron ('Steel' with 0% Carbon) starts to melt at 1,492 °C (2,718 °F), and is completely liquid upon reaching 1,539 °C (2,802 °F). Steel with 2.1% Carbon by weight begins melting at
1,130 °C (2,070 °F), and is completely molten upon reaching
1,315 °C (2,399 °F)
Do you guys even Wikipedia?!
Ok steel melts at 1k degrees, but have you read what I wrote? Let me repeat:
Kerosene's open air burning temperature is 350 degrees. Please explain how does it melt the 1k degrees steel.
Explanation is simple. You are either a intentionally deceiving people or are intellectually not equipped to have this discussion.
Google
jet fuel open air burning temperature. You will get the numbers from above: 2230 C in an engine, 1030 C in open air. Nobody told me what this was, I had to research it.
http://webserver.dmt.upm.es/~isidoro/dat1/eCombus.pdfSteel is fully ductile (it can be shaped by rollers) at 1050 C, but it begins to soften at around 700 C. Also at 1200+ C it may be fully liquid.
You don't need steel to be liquid to collapse a scaffolding structure, it has to be bend under weight enough, which happens at 700C. You build a steel support that needs to hold for example 1Kg. So you design it so it can hold 2Kg without issues. If you design it for 10Kg, then you use 10x more material for no additional results, it is simple economical reason to use sufficient while not being wasteful. So what happens to your little 2Kg capable support when it heats up to 800C? It can only hold 0.5Kg before it bends onto itself. It doesn't need to melt, have you ever worked with metals before?
Conclusion: Kerosene can burn at much more than 350 C and you state this number as the possible maximum. Steel will start losing it's integrity well below it's melting point but you choose it's melting point of 1500 C as minumum. You are deceiving yourself and others.
Did burning fuel melt steel in WTC? I don't know, I don't think so, it doesn't matter. But I don't go around telling people lies. Do your research before throwing stupid numbers around.
Bonus:
https://www.youtube.com/watch?v=Ne7W8UPdOroall nice numbers, but they're meaningless,
to know how much the steel really heats up, you don't need to know how hot kerosine burns, you need to know how much energy (heat) is added to the structure of the building.
You have to consider the amount of fuel burnt, the efficiency of the burning process (there's 3 possible chemical burn processes of jet fuel depending on how well the fuel was mixed with oxygen), the total mass of all the objects that were heated up including the air (which will absorb most of the heat, by the way), the specific heat of all the object heated, and from that calculate the deviation in heat, in other words how much things heat up from the temperature they started out at.
Since the building is quite large, and the fire was at the top of the building, it's not possible for all the steel in the building to have absorbed nearly enough heat to weaken by a large enough margin to allow structural failure.
on top of that, i would assume a building like that to have a large amount of redundancy in support so that even if the steel was somehow weakened to even 20% of their normal support it would still be able to stand without a problem. A certain level of redundancy is even required in all buildings as a safety measure.