Fire Melts Steel

By Proof

Back during the 9/11 controversy, one Hollywood twit scoffed at the idea that fire could melt steel. I thought of that when I saw the live video from the Daytona 500, where burning jet fuel ate through steel. Even though fire crews were there in a matter of seconds, the extreme heat did this kind of damage.

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Imagine a similar jet fuel fire with no suppressing foam, no water to douse it, eating away at the structural integrity of the WTC.

I don't know if actual evidence can persuade the conspiracy theorists, but as Mulder and Scully said, The Truth is out there.

For reference, here is a picture of the jet dryer truck with it's steel metal boxes intact.
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Update: It was pointed out by a commenter that this plating was aluminum instead of steel. When I first saw the video and the stills of what appeared to me to be chrome plated steel, I took this to be an example of "fire melting steel". I contacted a manufacturer of similar trucks who told me they indeed use aluminum over steel. I drew my conclusions based on observation and my experience with diamond plate steel in the past. I made an honest mistake based on not unreasonable assumptions.

Cross posted at Proof Positive


  1. As one who is about to receive a bachelors in civil engineering, I can tell you with a very high degree of certainty that a fire fueled by aerospace grade propellant, does burn hot enough to melt 50 ksi steel. Having said that, one thing that should be noted is that temperatures were reached in the blaze that would weaken structural steel to as low as 30% of its original design strength. Now as engineers, we like to design buildings with an FOS, or factor of safety. This is obviously done to take into account occasions when actual loads exceed those that were designed for. Generally, 1.5 is sufficient but from what I have read on the matter, the WTC may have been designed as high as 2.0. Now, let's say it had been designed at 2.0; that would mean that even if the steel would have been heated enough to lose 50% of the strength the building would be okay. But unfortunately, that did not happen. Having said all that I will close with one last thought. There's a simple reason all of the "Loose Change" type documentaries have architects (I have yet to see an engineer in any I've watched) and not engineers: no engineer, credible or otherwise, would ever risk their career, reputation, or liscensure for that matter, backing up the claim that the building was not weakened by the fire. I don't give a damn what any architect says, they take 3 classes on structural analysis that civil engineers do cram into one... And it's a sophomore level undergrad course, not even post graduate. I'll get off my high horse now. I enjoy the blog and have been a reader for a while, just never felt I could offer anything until now.

  2. So with all that said, even when an entire floor or even 5 had lost 70% of their strength, how would that affect the floors below that still had their full strength?

  3. Well you first have to understand that these each floor weighs close to a million pounds, once you factor in the outer walls, dead loads, the actual beams and columns themselves that hold the building together. We know that force = mass*acceleration. If you have one floor fail, weighing say, 1 million pounds, which is equal to 1 million slugs (we use slugs becasue it makes the units of measurement work correctly for the force equation, US custormary units are dumb), times the acceleration due to gragivy of 32.2 feet per second squared, you get a resulting force hitting the floor below it of 32.2 million pounds. I could never fully explain it as I have not taken structual dynamics, but just consider that using the aforemention FOS of 2.0, then, each floor is designed to carry a load of 2 million pounds. All it takes is one to fail and you get a domino effect, even though the columns on the lower floors are obviously deisgned to carry heavier loads than those on top, it wouldn't matter when we get to talking of forces of this magnitude. If you notice, I believe it was the north tower, which was hit second, actually fell first. This happened bacuse it was struck about 15 floors lower and thus, had an extra 15 floors of weight to carry vs. the south tower that was struck first, but stood for almost 2 hours before failure. Again, as I said, I am by no means an expert in the matter, but I do attend a university that just had our college of engineering named #18 in the country, ahead of the likes of Harvard, Yale, and MIT and I do feel like a have a better grasp on the concept of the forces that the building went through in this event than probably 95% of the general public. I hope this helps. Good evening.

    1. SWD: Thanks for coming by. We appreciate the technical info. But, don't sell yourself short on contributing on other posts. We can always use folks with level heads and common sense to help keep us focused and on the right track.


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