Physicist says heat substance felled WTC

Originally posted by bsbray11
The materials would have to be laid directly upon each other too in some significant amount, which would be pretty significant indeed when you're talking about globally collapsing one of the largest steel skyscrapers in the world. Powdered, as Aelita just mentioned, to really work, and then it would require a lot of heat to get the reaction started. The heat required to start a thermite reaction wouldn't naturally occur in the WTC.

I have seen a Thermite reaction start from a normal flame. All you need is powdered Aluminium and Iron, the rest takes care of itself!

It does have to be powder though....

Here is some info on Thermite:

Although the reactants are stable at room temperature, when they are exposed to sufficient heat to ignite (usually by igniting with a burning magnesium ribbon, but other methods are used as well, such as potassium permanganate and glycerine) they burn with an extremely intense exothermic reaction. The products emerge as liquids due to the high temperatures reached (with iron (III) oxide, up to 2500°C (4500°F)— although the actual temperature reached depends on how quickly heat can escape to the surrounding environment. Thermite contains its own supply of oxygen, and does not require any external source such as air. Consequently, it cannot be smothered and may ignite in any environment, given sufficient initial heat. It will burn just as well while underwater, for example, and cannot even be extinguished with water, as water sprayed on a thermite reaction will instantly be boiled into steam. This, combined with the extremely high temperatures generated, makes thermite reactions extremely hazardous even when appropriate precautions are taken.

Source

Stumason, everything I can find suggests thermite needs some pretty high temps to ignite, so I'm wondering how exactly the thermite you saw was ignited. How long was the flame applied? Was it in an enclosed space, where heat couldn't escape? I'm guessing it was using powdered materials, since you mentioned those.

It seems like you'd either have to have the fire in a small, enclosed area and applied for a length of time for there to be enough heat to light thermite, or else there is some variable to the ignition temperature that I'm missing.

thermite could naturally be ignited if the flame is hot enough, around 2000 degrees fahrenheit is usually enough ive heard. anyway aluminum must be in powdered form and they are usually mixed. its dangerous to create because the possibility of accidental ignition (so ive heard) if you make it into the type demolition crews use. to make it like that is overall dangerous.

anyway thermite doesnt melt the steel fully, just warps it really bad so its pretty weak. thats what causes the building to crumble and collapse usually in demolitions. Planted in the right spots you can take down any building.

interesting enough to demo the WTC the way they did it would take a hell of alot of this stuff, so the by products molten iron and such, should have taken a decent part of the dust particles. Meaning that alot of the fumes and dust from the fires should have the health side effects of molten iron and aluminum oxide (i think it was aluminum oxide). anyway thats why i wrote that 9/11 health effects article, because its the connection to the demolition thermite charges, hardly anyone has responded to it though.

Originally posted by grimreaper797
thermite could naturally be ignited if the flame is hot enough, around 2000 degrees fahrenheit is usually enough ive heard. anyway aluminum must be in powdered form and they are usually mixed. its dangerous to create because the possibility of accidental ignition (so ive heard) if you make it into the type demolition crews use. to make it like that is overall dangerous.

anyway thermite doesnt melt the steel fully, just warps it really bad so its pretty weak. thats what causes the building to crumble and collapse usually in demolitions. Planted in the right spots you can take down any building.

Couple of things, firstly you state it needs 2000 degrees to ignite, then you state its dangerous to mix the ally and iron due to possible accidental ignition? make your mind up, what 2000 degree heat sources are to hand while making thermite?

secondly, thermite is more than capable of melting steel, have you seen it in action? I've seen it burn through a car bonnet (hood) right through the engine block and then carry on making a whole in the tarmac underneath!! infact its very difficult to reverse the reaction once its started!!

I think we can safely say that 4500 degrees is enough to melt steel.

Melting point of Steel (give or take):

Most steel has other metals added to tune its properties, like strength, corrosion resistance, or ease of fabrication. Steel is just the element iron that has been processed to control the amount of carbon. Iron, out of the ground, melts at around 1510 degrees C (2750°F). Steel often melts at around 1370 degrees C (2500°F).

Source

As for the question about how the Thermite was lit. I believe, to be honest, it was done with a normal blowtorch. As it is powder, the smaller particles are easier to ignite. Once the reaction starts, even on a small amount, it will quickly emit enough thermal energy to kick start the rest of it.

to my understanding it has something to do with the mixing to make it into the demo charge that makes it dangerous, as i said i wasnt sure about that, just something i remember being told. But yes a good amount of thermite will melt it. but not much of it is needed to warp it, and before it melts it will warp...which under pressure will simply collapse before it has time to fully melt. as you saw the tower collapsed, this could be by warping the metal rather then metling it, mainly because it will collapse before it melts.

ok i got my story straight, its when the reaction takes place. you cant let molten iron get in water or BOOM, big explosion, aka not something people want. molten iron getting showered everywhere...really ugly stuff.

Is there some data about steel bending point ? We know when steel will melt but what about bending point ?

Originally posted by STolarZ
Is there some data about steel bending point ? We know when steel will melt but what about bending point ?

There's no "bending point," as that depend on the integrity of the steel and how much force is being applied to it to move it. There's info on when steel will lose certain amounts of integrity, though. It has to be heated to 600 degrees Celsius to lose 50% of its strength. That doesn't mean there has to be 600 degree fires; that means 600 degrees of heat has to be transferred into the steel itself. That's a real problem when steel conducts heat away as well as it does, not to mention the amounts of heat lost to the atmosphere and office materials, smoke, etc.




As you can see, steel won't really lose any strength at all even when heated to 350 degrees Celsius.

Also note that at a little over 400 degrees C, steel begins to glow in broad daylight. So we would've seen some glowing much beyond 400 C.

Thx.
If it's true than whole story about weakened steel it's just a untrue story.
If it's true than fires in WTC couldn't heat steel to enough temp. to lose its integrity what could've cause collapse. Right or wrong ?

Originally posted by STolarZ
If it's true than fires in WTC couldn't heat steel to enough temp. to lose its integrity what could've cause collapse. Right or wrong ?

Well, that's part of what's being debated here. But there's no direct evidence of any steel being heated to those temperatures until after the collapses. NIST, in their report, claim that the trusses under the floors were heated sufficiently. A couple problems with this, though.

Firstly, and critically, we can't even see the trusses to observe their damage or heat (or lack thereof) in any photos or video or anything else. They're all hidden.

Secondly, the evidence they do use is a few pictures showing slightly sloping exterior columns, which they claim was caused by failing trusses pulling columns inward from their weight. Aside from not being direct or conclusive evidence (they consider absolutely no alternative explanations), they also fail to show enough "buckling" to initiate a collapse by their own figures.

Hope that helps.

Edit: In case I didn't give you the answer you wanted: no, the towers could not have collapsed from the fires if the steel was not sufficiently weakened by it.

[edit on 19-4-2006 by bsbray11]