Professional engineer Jon Cole cuts steel columns with thermate, debunks Nat Geo & unexpectedly repr

reply to post by exponent


If you have evidence of how far the cladding was from the steel, I'd love to see it.

Just because it's called 'cladding' and it's on 3 sides it doesn't mean it was right on the steel.

It obvioulsy makes more sense than the trusses pulling in the more massive columns, especially when the trusses should not have got hot enough to sag anyway. If they sagged there was more than open air room fires going on.

It's amazing to me how you can blow off a more logical explanation because it contradicts the OS. You can argue all you want there is no evidence for either case, the OS is based as much on speculation as anyone else's claims.

Originally posted by ANOK
reply to post by exponent

 

If you have evidence of how far the cladding was from the steel, I'd love to see it.

Just because it's called 'cladding' and it's on 3 sides it doesn't mean it was right on the steel.

It obvioulsy makes more sense than the trusses pulling in the more massive columns, especially when the trusses should not have got hot enough to sag anyway. If they sagged there was more than open air room fires going on.

It's amazing to me how you can blow off a more logical explanation because it contradicts the OS. You can argue all you want there is no evidence for either case, the OS is based as much on speculation as anyone else's claims.

I've looked around online, and I have found one photo of the aluminum cladding being installed on the WTC:
You can see a lip at the top of the cladding.




You can see the where the gap in the bottom of the cladding piece allows the lip of the top of the cladding to go under.

This is the best depiction of the setting of the exterior columns and the cladding:


also seen here:
wtc.nist.gov...
Page 17 of the report (page 69 in pdf document)

Here too:


The way the aluminum cladding was set can be seen in both pictures. Each had a lip of the cladding go under the cladding above it. And from all accounts i've read, it was directly attached to the steel. Looking at the photos, there is just not enough of a gap between the two for the cladding to just "bend in" by itself by the heat. And you are the first and only truther to use this excuse that the exterior columns didnt bend inward, only the aluminum cladding from the heat. And I can tell you, it far and away from being the "most logical explanation" for it. Only in your mind, maybe, but in the rest of the world, not even close.

There's a lot to reply to in this post, but I want to start with a rather curious issue:

Originally posted by bsbray11
I don't have to demonstrate something on your behalf, when you are the one trying to lend credibility to NIST's report.
...
Again, a lack of evidence on your part is not my problem. I take this as an admission that you are arguing from ignorance and have no real case as to what exactly caused the WTC to "collapse."
...
Then you wouldn't need me to draw you a picture if you wanted to prove me wrong, would you?

This is not a thread where I came proposing a mechanism or explaining calculations. My entry into this thread was mocking you for your confidence, and asking you where you get that confidence from.

If you can't answer that, then why should people be listening to your opinions? If you can't show good reason why the WTC towers will behave similarly to the example cases you've given, then why should anyone believe what you say is accurate?

The rest of your post and two of ANOKs deals with the behaviour of the WTC trusses in fire, and the design and construction of the exterior of the building.

First, let me address the refraction point. I simulated a regular vertical lattice where there was a collection of material with a lower refractive index in a roughly hemispherical shape protruding from the building. No visible deflection was evident until the indexes of refraction differed by a significant proportion. So significant in fact that the material had an index of refraction under 1. I'll assume you know what this means.

The second point that's easy to address is the construction of the exterior walls and their fascias. Ignoring for a minute the endless photos of the WTC during construction, during occupancy, during the attack etc. There are also actual sources available from NIST (unsurprisingly).

Here's an image from the main NIST report, you don't even have to look in any subreports:


As you can see, there is only a few inches of space inbetween the perimeter columns and their aluminium cladding. There is no chance exterior cladding can be pushed in more than a few inches or so and not also result in column deformation.

Further to this, there is no mechanism for it! Bsbray posted images of column covers hanging off on the east side of WTC2, but this is not the side that was hit, and indeed none of the columns appear to be deflected inwards. This was the crux of both of your arguments, that inward deflection of the covers over the columns was visible, not column deflection. You can easily see how that is not physically possible. This has to be the most tenuous point of argumentation, because how is it possible that these things would deflect inwards if not with the columns they surround?

Next we come to the issue of thermal expansion. In no way am I arguing that this would not happen, the misunderstanding seems to be that once again the NIST report has not been read in anywhere near enough detail. NIST very explicitly describes the expansion of trusses and indeed notes its results on truss seats, on the expansion of the outer wall, on the disconnection of shear studs and the deformation of truss knuckles etc etc. A good place to start for this is NCSTAR 1-6C which details the modelling of individual components through to full floor assemblies when exposed to various fire and load conditions.

You probably also want to look at some of NCSTAR 1-5B which are probably the tests bsbray is referring to here:

Originally posted by bsbray11There's a video of NIST performing fire tests.

Do you already know what the results were? (Hint: no columns were pulled in, even with trusses heated to 700 C by a megawatt burner.)

This is an interesting quote, because the only other test I can imagine you're talking about is from NCSTAR 1-6B and there was no measurement of column deflection performed in either set of tests. You seem to be imagining things.

As for the temperature in the fires, once again we can turn to NISTs experimentation, in this case NCSTAR 1-5E, in which they modelled the behaviour of multiple workstations burning in various different configurations. Before we hear an objection based around 'but they used a burner!' they also detail the heat release rates of the various tests, and the peak values range from 11-16MW, including after the burner was shut off.

The temperature results are in the paper, but a rough summary of them is: Upper gas layer temperatures exceeded 800C for several minutes in almost all tests. Often this occurred several minutes after the flashover temperatures were reached. ANOKs first point is addressed by just looking at these results, there was more than enough time between impact and collapse for extremely high upper layer gas temperatures to develop.

For his second point, we can refer back to NCSTAR 1-5 and compare the gas temperatures with the graphs for insulated and uninsulated steel, there are too many to easily list here so I shall provide a quick summary again: The insulated steel performed well and took almost an hour to heat up to the surrounding gas temperatures, uninsulated steel fared poorly and relatively closely followed the gas temperatures (there's obviously a lot more technical discussion on this in the report, but most people won't want to read it)

Another point which seems to need discussing is the load factor of exterior columns pre and post aircraft impact. Bsbray relies upon the wording of a brief powerpoint presentation, which isn't exactly ideal. There are better NIST sources, both NCSTAR 1-2A and NCSTAR 1-6D. Once again a summary: There was about 2/3rds reserve capacity on average before aircraft impact, although this is obviously spread throughout the building and it was much more favourable near the top. However, at the impact area (which is where we're discussing) post aircraft impact things were much more unfavourable, an average would be useless as stresses were distributed around the building by design.

I may have been too hasty in my criticism of bsbray here, because once I did criticise him, he pointed out that in fact his estimate was pre-aircraft impact, and that the impact + fire would result in these margins lowering, so I will happily retract my point.

The last point that needs to be addressed is that of the difference between pushing out and pulling in. The key factor here is the time these behaviours occur. Thermal expansion occurs at all temperatures, it should be something we all have experience with I guess, and so it begins as soon as the temperature of the steel is raised even marginally. This all occurs relatively early in the fires spread, and the steel begins to push outward not long after ignition. However at this point, the vast majority of trusses are all still connected and still intact, they are providing a restraining force based on their temperature.

This does not last forever though, as the fires develop in intensity and heat the steel up further, parts of trusses start to break, truss seats and connectors start to fail, and trusses sag and are distorted enough that the outward force is reduced. After this point, whether the steel gets hotter or colder, the building is in serious trouble. The trusses are already severely deformed, and significant differences in forces being applied can be sufficient to break truss connections and further destabilise the outer wall. Not only this, but as trusses cool in a deformed shape, they will begin to exert an inward force due to their contraction.

These effects are obviously complex, which is exactly why I was challenging bsbray on this. You cannot develop a rule of thumb for the behaviour of this sort of system without involving several complex variables.

This is a pretty big post, and a lot of topics were covered, so I suggest instead of quoting every section of it and replying to each in turn, we pick a particular point we disagree over and discuss that. I won't take a lack of challenge to mean you agree with me, so feel free to select your biggest disagreemt and post that.

Originally posted by exponent
There's a lot to reply to in this post, but I want to start with a rather curious issue:

Originally posted by bsbray11
I don't have to demonstrate something on your behalf, when you are the one trying to lend credibility to NIST's report.
...
Again, a lack of evidence on your part is not my problem. I take this as an admission that you are arguing from ignorance and have no real case as to what exactly caused the WTC to "collapse."
...
Then you wouldn't need me to draw you a picture if you wanted to prove me wrong, would you?

This is not a thread where I came proposing a mechanism or explaining calculations.

If you don't have the fortitude to take NIST's burden of proof and show what exactly they were able to prove, then we have nothing to argue about.

My whole issue is with NIST's report, and the fact that they didn't prove their hypothesis in any way, and left it as a speculative issue.

Again, if you don't even want to argue the opposite, ie that NIST did offer proof of their hypothesis, then we have nothing to debate in the first place. You are copping out of the only point I am interested in making, just to save yourself the trouble of having to prove anything you say.


It should tell you something that when it comes down to the actual debate, you aren't able to accept the burden of proof. It should tell you that you already realize that you have no proof either.

You're either trying to show that NIST proved something, or you must already agree with me that they proved nothing about the collapse mechanism. It's either one or the other, but trying to argue both simultaneously is contradictory and ignorant. I'm not here to answer all your questions about why NIST's report contradicts all the other studies done on steel framed buildings. You can study up on that yourself and learn much more quickly than by bickering with me in some pointless pissing contest.



So I will resume this discussion when and if you are willing to man up and take the defense of the NIST report yourself, and take on its burden of proof. Otherwise I'm not interested in what would surely be a pointless discussion where you claim no burden to prove anything and instead ask me a million questions in return. I'm not claiming to already know what happened, either, so asking me questions would be wasting your time. The science has already been posted throughout this thread and you are apparently unwilling to even try to show how it justifies NIST in any way.

Originally posted by GenRadek
The way the aluminum cladding was set can be seen in both pictures. Each had a lip of the cladding go under the cladding above it. And from all accounts i've read, it was directly attached to the steel. Looking at the photos, there is just not enough of a gap between the two for the cladding to just "bend in" by itself by the heat. And you are the first and only truther to use this excuse that the exterior columns didnt bend inward, only the aluminum cladding from the heat. And I can tell you, it far and away from being the "most logical explanation" for it. Only in your mind, maybe, but in the rest of the world, not even close.

edit on 4/7/2011 by GenRadek because: edits

None of the those pics shows the aluminum cladding being directly against the steel. I didn't post them myself because they don't show anything about the cladding in any detail.

Those pictures are not to scale , you can't tell by looking at them how large the gap actually was.

There had to be a gap, galvanic corrosion is well known and would have to be accounted for, otherwise all the aluminum would have corroded. The same reason the statue of liberty is green. The aluminum would turn a powdery white.

Aluminum's galvanic potential is high, while steel's is low. On an auto body, when aluminum and steel are in direct contact, accelerated corrosion is evident. There are barrier technologies available to help with this condition when mixing metals, but at a significant cost impact.
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For example, when aluminum alloys or magnesium alloys are in contact with steel (carbon steel or stainless steel), galvanic corrosion can occur and accelerate the corrosion of the aluminum or magnesium.

corrosion.ksc.nasa.gov...

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Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte.

When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. For galvanic corrosion to occur, three conditions must be present:

Electrochemically dissimilar metals must be present

These metals must be in electrical contact, and

The metals must be exposed to an electrolyte [Rain, sea water]

www.corrosion-doctors.org...

This would have been accounted for by leaving a gap between the steel and the aluminum and if you are HONEST you have to admit it is a more logical conclusion than the SAGGING trusses pulled in more MASSIVE columns they were attached to. After 30 years the corrosion of the aluminum would be obvious.

I admit this might be wrong but I'm just trying to make sense of what NIST claims is bowing columns, which is not a logical explanation imo. I might be wrong but that doesn't mean NIST is right. If those are really bowing columns then it wasn't cause by sagging trusses, something else was going on.

Originally posted by exponent
Here's an image from the main NIST report, you don't even have to look in any subreports:

As you can see, there is only a few inches of space inbetween the perimeter columns and their aluminium cladding. There is no chance exterior cladding can be pushed in more than a few inches or so and not also result in column deformation.

That pic is not to scale, and yes the gap is a few inches, how big do you think I'm claiming the gap to be?

How much did the columns bow in? A few inches?

Even so IF it was bowing columns, how does that cause a complete global collapse with nothing left in the footprint. There would have to be floors left in the footprint for a progressive collapse, without that mass there is nothing to progress the collapse. The mass could not have left after it did the crushing.

Sorry but the OS is not the logical explanation.

reply to post by ANOK


Someone would either have to be blind or completely stupid to look at this picture and not be able to see that the aluminum cladding was obviously separated from the columns by the plane impacts:






I mean what else can you say?

If you think the aluminum panels hanging straight out into the air reflect where the steel column is behind them, you're off your rocker. It's right there in full color and yet people still deny it. I guess if everyone were as smart and observant as they should be, these debates would have already ceased to exist though, wouldn't they?

Here is a pic of the cladding from the collapse..



You can zoom in on this piece, A to zoom in, Z zoom out...

americanhistory.si.edu...

I see no sign of corrosion at all, it looks clean and shiny. If it had been in direct contact with steel for 30 years it would show signs of corrosion, white and powdery.



Look close at this pic, especially the left side, you can see the cladding is not against the steel...

Originally posted by bsbray11
Otherwise I'm not interested in what would surely be a pointless discussion where you claim no burden to prove anything and instead ask me a million questions in return. I'm not claiming to already know what happened, either, so asking me questions would be wasting your time. The science has already been posted throughout this thread and you are apparently unwilling to even try to show how it justifies NIST in any way.

What I am unwilling to do is participate in a discussion where you can achieve 'victory' by simply denying everything you see. This is a common mode of behaviour for 911 truthers, in that they have a rough idea of what they think happened, and so any evidence they believe to contradict it is dismissed out of hand.

For example, you believe that thermal expansion of trusses is a weakness in NISTs theory, and so you are promoting it as if it was a fact that the expansion forces will always exceed pull-in forces, and as if NIST never mentioned them.

You don't have any evidence for this, and clearly you were unable to prove it in any way when challenged, but doubtless you still believe it.

This is the danger of assigning me the burden of proof, that it's very easy to assume your preferred case is the 'default position', the 'null hypothesis'. Clearly this is incorrect, and while I am happy to defend the NIST report from most unwarranted criticism, unless that criticism is seriously astounding, then the NIST report will remain by a long way the most coherent and supported theory yet created.

If you can accept that your preferred hypothesis, whatever it is is not the default position, then I will participate.

Originally posted by ANOK
That pic is not to scale, and yes the gap is a few inches, how big do you think I'm claiming the gap to be?

How much did the columns bow in? A few inches?

What makes you think that picture is not to scale? The bowing was multiple feet at multiple points.

Even so IF it was bowing columns, how does that cause a complete global collapse with nothing left in the footprint. There would have to be floors left in the footprint for a progressive collapse, without that mass there is nothing to progress the collapse. The mass could not have left after it did the crushing.

There were floors left in the footprint, although some undoubtedly did spread out after the collapse. Fill a straw with say salt, let it drop straight down onto a desk, see how much stays confined to the straw's footprint.

Originally posted by bsbray11
If you think the aluminum panels hanging straight out into the air reflect where the steel column is behind them, you're off your rocker.

This makes no sense, if the edges of the building we're seeing in the bowing pictures is pushed further out, then the resultant bowing would be greater, not less. This goes against what you have been saying. How can this possibly help you?

Originally posted by exponent

Originally posted by bsbray11
Otherwise I'm not interested in what would surely be a pointless discussion where you claim no burden to prove anything and instead ask me a million questions in return. I'm not claiming to already know what happened, either, so asking me questions would be wasting your time. The science has already been posted throughout this thread and you are apparently unwilling to even try to show how it justifies NIST in any way.

What I am unwilling to do is participate in a discussion where you can achieve 'victory' by simply denying everything you see. This is a common mode of behaviour for 911 truthers, in that they have a rough idea of what they think happened, and so any evidence they believe to contradict it is dismissed out of hand.

You're not really worried about that, because you haven't posted any proof in the first place.


Look man, you were just trying to weasel out of any burden of proof in your last post. That's proof enough in itself, that you aren't even trying.


So I take it that you aren't willing to defend NIST's report. Fine. Then we have nothing to argue about!

Originally posted by bsbray11
Look man, you were just trying to weasel out of any burden of proof in your last post. That's proof enough in itself, that you aren't even trying.

So when you avoid answering my questions like right now, it's totally fine and you're still unassailable. However when I answer your questions but refuse to join in a debate where the conditions are biased, I'm not even trying?

If you don't have answers for my questions then fine, but don't pretend like you're not answering for some philosophical reason.

So I take it that you aren't willing to defend NIST's report. Fine. Then we have nothing to argue about!

I'm perfectly happy to defend NISTs report to anyone who acts reasonably, i'm not about to accept the burden of proof against someone who will just deny evidence consistently. We've been debating for literally years and you still don't seem to understand some of the very basics.

Originally posted by exponent

Originally posted by bsbray11
Look man, you were just trying to weasel out of any burden of proof in your last post. That's proof enough in itself, that you aren't even trying.

So when you avoid answering my questions like right now, it's totally fine and you're still unassailable.

I'm not avoiding anything. I told you straight up that I don't owe it to you to answer any questions about 9/11, because I'm not proposing any specific theories here, or supporting any of them. You either show me NIST's proof, or stop whining like a baby just because they never came up with any. You don't have any control over that.

I have issues with the NIST report, and the other 9/11 reports. If you can't answer my questions, that's fine! You don't have to talk to me.

You don't want to even try to defend NIST's report, despite what you say, and you've made that perfectly clear above when you copped out of any burden of proof whatsoever. So you're done. Good try. Now go find someone else to play with. You already must realize they proved nothing, to have been trying to cop out of your burden above. I have nothing else to demonstrate to you.

I'm perfectly happy to defend NISTs report to anyone who acts reasonably

Yeah, right. Yet you take the time to respond to me anyway. A lot of damned sense that makes.

You were just trying to cop out of having to prove anything just a couple posts above, and act like it was my job to prove everything to you, when I didn't write the NIST report, and it didn't prove anything in the first place. Get real. It's about the most immature thing you can do on these forums to try to spin the burden of proof when you realize you can't prove your own arguments. That's proving me right. My whole point is that NIST has no proof, and you're only proving me right by copping out of any burden to defend their claims. It doesn't take a genius to get the situation straight here, no matter how many posts you're about to spend arguing something erroneous. It was never my responsibility to explain 9/11 to you. But it was NIST's. When you claim otherwise you are lying.

Any time you're ready to post NIST's proof, I'll be right here. Too bad for you NIST themselves already admitted they only had a hypothesis, and no proof, so what could that possibly leave you with to argue?



Empty words, that's all. You can't get any more basic than determining where the burden of proof lies, and it was NIST's burden, as assigned by Congress. That's basics. That you don't understand. Congress didn't assign the investigation to me. Keep crying about it, and trying to spin the burden back around on me. It's been tried many times before and it's apparently the last option of someone who has nothing to prove.

Originally posted by bsbray11
I'm not avoiding anything. I told you straight up that I don't owe it to you to answer any questions about 9/11, because I'm not proposing any specific theories here, or supporting any of them. You either show me NIST's proof, or stop whining like a baby just because they never came up with any. You don't have any control over that.

Oh please, your attempted antagonism is too weak to even bother retaliating. You are avoiding answering these questions because you know that if you were placed in a situation where you cannot just deny constantly, you would be unable to answer.

I have issues with the NIST report, and the other 9/11 reports. If you can't answer my questions, that's fine! You don't have to talk to me

You don't want to even try to defend NIST's report, despite what you say, and you've made that perfectly clear above when you copped out of any burden of proof whatsoever. So you're done. Good try. Now go find someone else to play with.

This is a hilariously failed cop-out too. Did you miss the post earlier on this page how I explained how you were distorting the truth, lying about tests and despite having years to do so were still unaware of even what the 'official story' says?

I'm not the one copping out here, you want to have your cake and eat it, free to challenge the NIST report without ever being called out on actually adhering to facts.

Yeah, right. Yet you take the time to respond to me anyway. A lot of damned sense that makes.

One always hopes you can be reasonable.

You were just trying to cop out of having to prove anything just a couple posts above, and act like it was my job to prove everything to you, when I didn't write the NIST report, and it didn't prove anything in the first place.

You might have noticed, I wrote the whole post showing where you were wrong and I wrote about the burden of proof issue. You then failed to respond to any of my replies, putting you in the position of copping out. It's a nice attempt to twist the situation, but it is all on one page. It's not like people can't go up and read the answers I gave, and see your running away.

Get real. It's about the most immature thing you can do on these forums to try to spin the burden of proof when you realize you can't prove your own arguments. That's proving me right.

This is exactly what you're doing, plus it's especially ironic you're pronouncing yourself 'right' because you have now failed to address the points put forward.

My whole point is that NIST has no proof, and you're only proving me right by copping out of any burden to defend their claims. It doesn't take a genius to get the situation straight here, no matter how many posts you're about to spend arguing something erroneous. It was never my responsibility to explain 9/11 to you. But it was NIST's. When you claim otherwise you are lying.

You're right, it really doesn't take a genius to get things straight here, but just in case someone can't be bothered reading the last couple of pages, here's how it goes:

• Bsbray makes a number of positive claims and allusions of engineering knowledge in order to determine that floor sagging is impossible and that the NIST report should have seen outward bowing
  
• I point out that he was considering different floors and that NIST indeed did see outward bowing
  
• Bsbray demands that instead of him providing evidence for his claims, I am wholly responsive to him, and must answer every question of his to his ultimate satisfaction, despite the fact that we've been debating for years and all he ever does is put his fingers in his ears and deny what's right in front of him
  
• I point this out
  
• Bsbray throws his toys out of the pram

It's as simple as that. I gave you your answers, I just refuse to play a game where I know I can never win. And before you start saying "aha that is because NIST never proved anything", then no. It is because I cannot trust you to accept even the most rational and obvious of evidence. For god's sake you argued against bowing by providing a mechanism that would increase bowing. Sometimes, I just don't know.

reply to post by exponent


You're still responding to me.

I guess that means you still want to talk to me and are still taking me seriously.


Now are you going to show what the NIST report proved or admit they didn't prove anything?


I already told you I have no interest in any of your semantic pissing contests if you're not even going to try to show that the official reports proved anything. If you think I'm too stupid to understand what NIST's proof is, then just stop talking to me. The fact of the matter is that they even admit they only have a hypothesis. I'll be waiting to see what you think they proved.

Originally posted by bsbray11
Now are you going to show what the NIST report proved or admit they didn't prove anything?

You asked me questions and I answered them. If you have any more to ask I will do my best to answer them too. I don't care what you want to believe about burdens of proof.

So, do you have any more questions? You were clearly wrong on a few facts, so I guess I have to hope you no longer disagree.

reply to post by exponent


Yes, I have plenty more questions.

Do you think NIST actually proved something about the WTC collapses? If so, what?

Originally posted by bsbray11
Do you think NIST actually proved something about the WTC collapses? If so, what?

Well lets start with the early and simple stuff. I think NIST proved sufficiently that:

• WTC workstations would readily burn and produce temperatures significant enough to damage steel
  
• These temperatures were maintained for a long enough period to affect the steel
  
• Steel with damaged insulation would heat up very quickly
  
• Insulation damage was very likely

Any disagreement?

Originally posted by exponent
Well lets start with the early and simple stuff. I think NIST proved sufficiently that:

• WTC workstations would readily burn and produce temperatures significant enough to damage steel
  
• These temperatures were maintained for a long enough period to affect the steel
  
• Steel with damaged insulation would heat up very quickly
  
• Insulation damage was very likely

Any disagreement?

None of that proves, or is even evidence, that a 110 story building can globally collapse from one hours worth of fire.

To go from damaging steel to causing complete failure, with no mass left in the footprints, is a huuuge stretch of the imagination, and physics.

How hot do you think an open air room fire will get in an hour? Well here is an official test of that...

There is fairly broad agreement in the fire science community that flashover is reached when the average upper gas temperature in the room exceeds about 600°C. Prior to that point, no generalizations should be made: There will be zones of 900°C flame temperatures, but wide spatial variations will be seen. Of interest, however, is the peak fire temperature normally associated with room fires. The peak value is governed by ventilation and fuel supply characteristics [12] and so such values will form a wide frequency distribution. Of interest is the maximum value which is fairly regularly found. This value turns out to be around 1200°C, although a typical post-flashover room fire will more commonly be 900~1000°C. The time-temperature curve for the standard fire endurance test, ASTM E 119 [13] goes up to 1260°C, but this is reached only in 8 hr. In actual fact, no jurisdiction demands fire endurance periods for over 4 hr, at which point the curve only reaches 1093°C.

The peak expected temperatures in room fires, then, are slightly greater than those found in free-burning fire plumes. This is to be expected. The amount that the fire plume's temperature drops below the adiabatic flame temperature is determined by the heat losses from the flame. When a flame is far away from any walls and does not heat up the enclosure, it radiates to surroundings which are essentially at 20°C. If the flame is big enough (or the room small enough) for the room walls to heat up substantially, then the flame exchanges radiation with a body that is several hundred °C; the consequence is smaller heat losses, and, therefore, a higher flame temperature.

How hot do you think the room would get in one hour?

Don't forget to account for thermal exchange...

It is common to find that investigators assume that an object next to a flame of a certain temperature will also be of that same temperature. This is, of course, untrue. If a flame is exchanging heat with a object which was initially at room temperature, it will take a finite amount of time for that object to rise to a temperature which is 'close' to that of the flame. Exactly how long it will take for it to rise to a certain value is the subject for the study of heat transfer. Heat transfer is usually presented to engineering students over several semesters of university classes, so it should be clear that simple rules-of-thumb would not be expected. Here, we will merely point out that the rate at which target objects heat up is largely governed by their thermal conductivity, density, and size. Small, low-density, low-conductivity objects will heat up much faster than massive, heavy-weight ones.

It's just a ridiculous assumption that any steel could fail after an hour of fire. IF any steel did fail then all the other steel that didn't fail would take up the extra load. For the whole building to fail then the majority of the steel would have to have failed.

All materials weaken with increasing temperature and steel is no exception. Strength loss for steel is generally accepted to begin at about 300ºC and increases rapidly after 400ºC, by 550ºC steel retains about 60% of its room temperature yield strength.

Do you understand factors of safety requirements? Building components should be at least 2% and are often higher. 2% means it should hold it own weight twice. If the steel lost 50% of its weight it would still hold.

FOS is not just made up...

engr.bd.psu.edu...

www.mech.utah.edu...

Of 270 examined core columns only three had temps of over 250C., and they showed no temps over 600C for any significant time.

wtc.nist.gov...

Fire did not collapse those buildings...

Originally posted by ANOK
None of that proves, or is even evidence, that a 110 story building can globally collapse from one hours worth of fire.

I know, I'm trying to take it slowly so we avoid massive posts where we argue with each other without addressing specific points.

To go from damaging steel to causing complete failure, with no mass left in the footprints, is a huuuge stretch of the imagination, and physics.

You're stretching a bit here, there certainly wasn't 'no mass' left in the footprints, just that perhaps it was less than some expected, we'll get to the collapse later i'm sure.

How hot do you think an open air room fire will get in an hour? Well here is an official test of that...

What you've quoted isn't an 'official test of how hot a room will get'. How hot a room will get we can answer thanks to NIST. They burned several WTC workstations in a compartment and here are some of the temperature graphs from NCSTAR 1-5E:



I picked a few at random here so feel free to select your own, but what I am trying to show you is that ASTM E119 isn't supposed to replicate an actual fire condition, it's a way of ensuring standardised testing of elements under fire conditions. Fires will easily hit peak temperatures within a few minutes, frankly you can probably agree with this just from personal experience. I know I have been around a few fires in my time and they certainly didn't take an hour to get up to well over 600C (my aluminium melted).

It's just a ridiculous assumption that any steel could fail after an hour of fire. IF any steel did fail then all the other steel that didn't fail would take up the extra load. For the whole building to fail then the majority of the steel would have to have failed.

Why do you think they fireproof steel to give it a 2 hour rating, if steel is in no danger of failing from a fire? We'll get to the collapse later on I hope.

Do you understand factors of safety requirements? Building components should be at least 2% and are often higher. 2% means it should hold it own weight twice. If the steel lost 50% of its weight it would still hold.

FOS is not just made up...

You're right it's not made up, but "2%" doesn't mean what you think it does. The WTC certainly had factors of safety, and after the impact it still survived for some time. I am certainly not blaming the original construction of the WTC in any way, it was the resultant fire that was critical to collapse (although fireproofing loss through impact was equally important)

Of 270 examined core columns only three had temps of over 250C., and they showed no temps over 600C for any significant time.

Unfortunately those 270 weren't from actual fire regions, and NIST never actually recovered any column they predicted to have high temperatures, so if they had found some they would have had to correct their theory. I agree that this sucks and doesn't help NISTs case, but they can't be blamed for not inspecting steel they didn't have.