Comparison of Thermite Reaction Demonstration to Video Footage of Material

[MrSammo1]

Comparison of Thermite Reaction Demonstration to Video Footage of Material Dropping from WTC 2 Just Prior to Collapse on Sept 11th 2001

http://www.checktheevidence.com/911/Thermite.htm

[jschurchin]

1. They do appear very.......

similar. It is a possible explanation for the material we see.

[hack89]

2. Why would they use thermite?

and why on the external columns where it would be visible?

High explosives on the core columns would be more then enough and it would be hidden from video cameras.

Thermite makes no sense. It is also not used for CD - are you saying that the WTC were not a typical CD? And if it was a unique event, why can you say that it was obviously CD?

[Bouvet_Island]

3. Hack89,

do you have a background in controlled demolition?

What is your basis for saying thermite would make no sense? To some unknown enterprise planning this, with unknown experience and technology? Have a similar building to the wtc (so much steel ...) been controlled demolished before? With people working in it the days before, them not supposed to notice anything. It obviously would be a desirable goal to minimize blast and sound.

Your theory seem to be a clear conviction that there was no explosives. You should clearly say that "no explosives would be more than enough", if that is what you mean.

[hack89]

4. If if was "obviously" CD ..

then it would be safe to assume that standard techniques would be used. If not, it was not a standard CD, so how could it be recognized as CD? You can't have it both ways.

As for the thermite, Google the subject and it doesn't take long to figure out that thermite is not used for CD. I challenge you to find a single example of CD using thermite.

You also raise an interesting point - who ever did 9/11 must have had significant experience in demolition. It was done perfectly - twice (three times if you include WTC 7). Do you expect me to believe that an inexperienced company using untested techniques could pull of the greatest CD feat of all times - and do it flawlessly? I don't think so.

There is no evidence of CD - structural damage and fires were adequate. There is no evidence of explosive residue, no witnesses to a massive effort to wire up the towers. Most importantly, no plausible scenario has been suggested - why can't someone tell me where the explosives were placed and how many tons of explosives were used?

[Kevin Fenton]

5. It wouldn't

The largest building destroyed by CD before 9/11 was 30 stories, the twin towers were 110 each. That is a big difference right there. Other buildings destroyed by CD are subjected to test firings, the WTC wasn't. Other buildings have all the stuff (i.e. partition walls, etc.) removed, the WTC didn't. Other buildings fall neatly where they should have (unless there was a mistake, in which case they threw bits out), the Twin Towers threw debris in all directions (although 7 didn't).

"If not, it was not a standard CD, so how could it be recognized as CD?"
7 looks like a standard CD, 1 and 2 do not look like a standard CD in some respects.

It is claimed to be CD for 3 reasons:
(1) The impact damage and fires are not adequate. If you think they are adequate, please quantify them;
(2) Buildings don't pancake;
(3) The photos and videos support CD (squibs, etc.), not pancaking (unpancaked sections are visible).

[hack89]

11. Answers..

1. I have posted many links from NIST, ARUP, MIT, FEMA concerning the fires and damage. I know that you and everyone else will find some way to dismiss them. My point is that it is impossible to argue that the WTC could not have collapsed without explosives. Many engineers have shown several collapse mechanism and no one questions that the fires/impact alone were enough to bring them down. The entire engineering community does not have a problem with it. All you are left with is an unproven conspiracy of massive proportions to quite the entire world's engineering community.

2. Why don't buildings pancake? - it was a unique event so you have no idea what it should look like. Massive weight and gravity producing huge dynamic forces would make a building pancake.

3. Where are the explosive residues? - Hoffman would have you believe that at least 500 tons of explosives were used. That would have left detectable residue.

[Kevin Fenton]

14. Not good enough

It is not enough to merely post links, it is necessary to understand and be able to discuss the content of the links. The studies you cite are all contradictory (for example they can't agree on how many columns were severed in which core); therefore, they cannot all be right - NIST itself modeled three cases; in two of them the towers did not collapse - why should anyone believe that the case in which the towers collapsed was the right one, especially when its input variables were demonstrably inaccurate?

As for the collapse mechanisms proposed by engineers, for example:
(1) Eagar's angle clips theory has been publicly repudiated by other engineers. If other engineers think it's no good, then why should I pay any attention to it?
(2) Greening doesn't even know how much the towers weigh or that they had a hat truss (or even which way round the South Tower's core was). If he doesn't know the first thing about the towers, why should I pay any attention to him?

"Many engineers have shown several collapse mechanisms"
Yes, that's because they can't agree. The reason they can't agree is that there isn't a "right" answer - if there was, they would have found it by now. If the entire engineering community doesn't have a problem with it, then why isn't there anything like a consensus on the failure mode?

"All you are left with is an unproven conspiracy of massive proportions to quite the entire world's engineering community."
You appear to be expressing the belief that the WTC collapse is relevant to all engineers throughout the world and that they are all acquainted with the various theories. Please quantify the percentage of engineers who, in your opinion, work on high-rise buildings and for whom the NIST report is relevant.

"Massive weight and gravity"
Please quantify. The adjective "massive" is insufficient.

If you don't know how much impact damage there was, then how can you know it was adequate to cause the collapse?

[hack89]

16. OK.

Then tell me how it was done? Lets stop beating around the bush - I say that with the amount of explosives CTrs say they need on every floor it would be impossible to do without detection. The logistics are the details that CTrs always gloss over. I don't believe in CD because no one can present a plausible scenario whereby two massive towers with tens of thousands of people could be prepared for CD without no one noticing a thing.

You say that the official story is implausible yet you turn around and expect me to believe that someone perfectly pulled off the greatest CD of all times with untested techniques. Think what you are saying!

[dailykoff]

18. hey Mr. Logistics

since this "tons of explosives" thing seems to bother you and no one else, exactly how many tons do you think would be needed?

[hack89]

21. I don't have to account for:

1. Steel beams being flung great distances.

2. Visible squibs on every floor.

3. Hoffman's pyroclasitic flows indicating a massive deficit of energy.

I would use high explosives on a ground level floor and let gravity pancake of the towers - you know, like a normal CD. Maybe a ton or so.

You are arguing for a non-standard CD - I'm just curious how it was done.

[dailykoff]

23. But you're the only one who cares

about the exact quantity of explosives. In fact it's the only technical point you do care about.

But it really doesn't make any difference, does it?

[hack89]

25. The fact that it was impossible makes no difference?

You, like the entire 9/11 research community, can't make the leap from theoretical to reality. There has to be a point where you can answer the basic question "how was it done?". People know that things don't happen by magic - you expect me to believe that something that would take weeks was done in 12 hours in absolutely secrecy. I live in a reality based world - not faith based like yours.

[dailykoff]

27. What makes you think it was impossible?

For example, how many tons of explosives do you think it would require? Give me a figure, for once.

[hack89]

29. CD is very possible - any building can be brought down

with enough explosives. I say that your theory is impossible. Your evasions simply reinforce that point.

[dailykoff]

31. Impossible why?

Give me some figures for once. What would it take in your opinion?

[hack89]

33. Because it is nothing but hand waving ...

it is impossible for you to even articulated a plausible scenario. If it makes you feel better, I would be willing to entertain CD once you flesh out your theory and provide some details.

You are the one that needs to provide some figures - it is your claim. Without details why should I believe you?

[dailykoff]

35. The figures are below. Tell me why they're wrong. (n/t)

[hack89]

38. Because there aren't enough charges to..

destroy enough core columns and still account for the squibs.

[dailykoff]

39. Forget the squibs. Give me some figures, okay? (n/t)

[hack89]

41. 48 charges on the first floor is all you need. nt

[dailykoff]

43. All you need to bring down a barn. (n/t)

[hack89]

45. This is a good point to end the conversation

since you are no longer serious. I'll let you have the last word if you wish.

[Name removed]

47. Deleted message

Message removed by moderator. Click here to review the message board rules.

[Name removed]

77. Deleted message

Message removed by moderator. Click here to review the message board rules.

[dailykoff]

83. Good calculations! (n/t)

[hack89]

88. You do realize, don't you ...

that the picture is of a reinforced cement building - why don't you compare apples to apples?

[simonm]

91. Same Principle - The picture is just an example

Same physics applies. You can't break something down without dismantling its back bone (cores).

[hack89]

99. Sure - if you say so.

Except concrete building don't have cores. But never mind.

[hack89]

89. Where in your calculations do you account for the energy for

the tossed steel beams and Hoffman's pyroclastic flows? Remember that you need to demonstrate a 10 fold increase in energy over the building's gravitational potential energy.

And how do you account for the Thermite on the perimeter columns?

[simonm]

92. Never mentioned energy - just cutting estimates

the tossed steel beams and Hoffman's pyroclastic flows?

In the post you responded to I never mentioned pyroclastic flows.

Remember that you need to demonstrate a 10 fold increase in energy over the building's gravitational potential energy.

In the post you responded to I never calculated energy.

Are you trying to divert from the topic or just having problems focusing?

And how do you account for the Thermite on the perimeter columns?

Ah, a question that relates to the post! Finally. If the blueprints were available the reasons would probably be more obvious. Unfortunately, it is still top secret today.

[hack89]

97. Silly me, thinking that any calculations for CD ...

must account for the "proof" of CD. If I remember correctly, you are the one who told me on several occasions that the "evidence" for CD included the steel beams and pryoclastic flows. Since your calculations don't account for the "evidence" they, by definition, must be useless.

Are you saying that you can't be held accountable for your previous posts? Were you not serious when you made them and that the pyroclastic flow and steel beams are not proof of CD?

[Name removed]

64. Deleted message

Message removed by moderator. Click here to review the message board rules.

[hack89]

74. Dailykoff said it took 12 hours - go argue with him, nt

[dailykoff]

79. 12.6 hours per tower. (n/t)

[hack89]

75. I didn't see in your demo link ..

where it made an estimation of how many tons of explosives were needed. In case I missed something, do you mind just telling what the answer is?

I didn't see any energy calculations so I don't think the authors of that site have any clue.

[dailykoff]

78. The rough and ready answer is 11 tons

based on your very helpful estimation:

2,000/47 x 504 charges = 10.72 tons per tower.

[hack89]

82. But that undermines simonn's arguments about the ..

ejected steel columns and the pyroclastic flows so it can't possibly be right.

A bunch of small charges scattered around each tower could not have possibly accounted for the "proof of demolition" that her link describes.

You two need to get your story straight - you both can't be right.

[dailykoff]

84. I'll defer to simonm.

Meanwhile, you wanted figures, and you got them.

[hack89]

86. 500 tons per tower makes sense to you? OK...nt

[dailykoff]

65. A ton of what?

And let's say your pancaking plan worked (it wouldn't, but never mind). A ton of explosives on the ground floor would mean that each charge weighed about 45 pounds (2,000/47 columns = 42.6).

Why is it so difficult to imagine 500 45-pound charges distributed throughout each tower, which would produce a result more like what we saw on 9/11?

[hack89]

80. Why wouldn't it work?

that would be a classic CD - lots of weight and gravity working straight down. That steel structure would disintegrate like matchsticks as all the joint and connections were overstressed by the massive dynamic loads.

[dailykoff]

81. Because the height-width ratios were 6:1

meaning the lateral loads would simply topple them.

[hack89]

85. Please do a vector analysis for me..

that describes the relative strength of the lateral and gravitational forces, because you are not making much sense. Perhaps if you could provide a little more detail I will understand.

[dailykoff]

87. If you don't understand, I can't help you. I'm sorry. (n/t)

[hack89]

90. You really have no clue, do you?

It is curious how you never can answer a question that calls for any understanding of basic physics.

I do understand - the downward vector is many orders of magnitude greater then the "harbor winds" that you feel could topple the towers.

[Kevin Fenton]

49. Still no numbers

"I say that with the amount of explosives CTrs say they need on every floor it would be impossible to do without detection."
(1) The vast majority of CTers do not say there were explosives on every floor. They say there were explosives every 10 or so floors.
(2) With reference to the number of office workers ordinarily inside the lift shafts, how many of them would notice a technician attaching explosives to a core column there?

The impact and fire damage is inadequate. If you are unable to quantify it, how can you possibly argue that it is adequate?

[hack89]

50. So what was the internal damage ?

how do you counter the official story?

What about the explosives on the perimeter columns? Or do you dismiss the squibs like dailykoff?

[Kevin Fenton]

52. Damage, etc.

The best estimate of the internal damage I have seen so far is NIST's base case, which said 3 core columns were severed in the North Tower and 5 in the South Tower, although I think the South Tower estimate is a little over, because I disagree with the plane speed (I prefer MIT and NIST's complex motion analysis here). NIST actually did a proper model (although it may well be significantly inaccurate due to lack of experience with planes hitting similar buildings), Greening, for example, just pulled a number out of his ear.

In NIST's base case the planes destroy approximately 10.5% (WTC 1) and 13.5% (WTC 2) of the gravity load-bearing structure, so what happened to the rest of the towers?

Explosives on the perimeter columns. I don't see any explosives going off on the perimeter columns, so I can't say they are definitely there - the "squibs" are coming from the core area. It's obviously much more difficult to place explosives in the perimeter than in the core (at least on many floors) and the towers don't fall the way they should if the CD had been done right - they throw debris several hundred feet in all directions - so "no explosives in the perimeter" seems a decent hypothesis.

[hack89]

53. So why are the NIST damages inadequate?

every technical analysis I have seen says that in combination with the fires and the massive weight above the impact zones there was enough damage.

Can you link to a technical analysis of the damage that says it was inadequate - perhaps then we can compare expert opinion to expert opinion.

[Kevin Fenton]

67. NIST

You can find NIST's estimate of base case impact damage in this report:
http://wtc.nist.gov/NISTNCSTAR1-2.pdf
The discussion of the base case impact damage for the North Tower begins on page 171 (p. 283 of the .pdf)

The discussion of the base case impact damage for the South Tower begins on page 217 (p. 331 of the .pdf)

The buildings would not have collapsed due to base case damage. For example, NIST states, "Upon a preliminary examination of the middle cases, it became clear that the towers would likely remain standing." (p. 144/194 of the Main Report)

The input variables for the base case are demonstrably more accurate than those for the severe case, so how can the severe case have the stamp of engineering legitimacy without that being extended to the base case?

[hack89]

70. You don't understand.

I am looking for an engineering analysis from the 9/11 research community. Don't you think that after four and a half years we can move beyond amateur analysis and google engineering and look at analysis by real engineers? Surely there must be something you can give me besides your opinion?

There have been numerous collapse mechanism suggested by different people and organizations - the comments to the NIST report is a good place to start. You do understand how science works don't you - theories are devised and experiments are conducted. The results are peer reviewed and issues are raised. The theories are revised to reconcile the differences and new experiments are conducted. The NIST report you keep harping on is the just the beginning of the process - it is way premature to say that NIST is wrong or that someone else is right. There's a couple of years of science ahead of us.

The point to take away is that none of the organizations participating in the process disagree that the impact of the planes plus the fires were sufficient to cause the collapse. So on one hand I have the opinion of professional engineers and scientists. On the other I have your lay opinion. Don't you find it puzzling that there is a lack of such analysis from the 9/11 research community?

[Kevin Fenton]

102. You appear to have difficulty focusing

You asked for "a technical analysis of the damage that says it was inadequate - perhaps then we can compare expert opinion to expert opinion"

NIST's base case is clearly "a technical analysis" and it clearly says that the damage was inadequate. Further, it is clearly better than NIST's severe case analysis, because the input variables are more accurate, and it is better than the theories advanced by other engineers, because it is more detailed. It is therefore currently the best analysis and says the damage was inadequate - that is the point "to take away".

"The NIST report you keep harping on"
Excuse me? I keeping harping on about it? Are you suggesting we should ignore the NIST report? On what grounds? In favour of what? Thomas Eager? Frank Greening?

"none of the organizations participating in the process disagree that the impact of the planes plus the fires were sufficient to cause the collapse."
I don't care what they believe, I care about their numbers - either they add up, or they don't. And they don't.

[hack89]

104. So you have decided to latch on to an ...

old (relatively speaking) preliminary report and to ignore all subsequent work by NIST and others.

At least you are honest in your closed mindedness. It certainly does help keep your mind uncluttered with unnecessary facts.

A simple question for you: don't you agree that in the scientific process, the initial theories are often shown to be wrong or incomplete? That's why there is experimentation and peer review. Why are you fixated on the start point and not where the science is right now? Are you concerned that the ultimate answer is not what you want?

[Kevin Fenton]

108. Preliminary report? Old?

The report I linked to was called the "Baseline Structural Performance and Aircraft Impact Damage Analysis of the World Trade Center Towers", which was published in September 2005. You appear to be confusing it with the "Baseline Structural Performance and Aircraft Impact Damage Analysis of the World Trade Center Towers (Draft)", which was for public comment.

I believe this is NIST's last publication on the topic. To what subsequent work are you referring?

I fully agree that initial theories are often wrong and incomplete. In fact that is my whole point.

[hack89]

112. So we wait for subsequent research , don't we?

there is no indication that the answer will be any different but I am willing to wait. I think the ARUP study will be particularly interesting. Face it, at the end the of day, the results will be the same.

[hack89]

107. I found the rest of the quote

Upon a preliminary examination of the middle cases, it became clear that the towers would likely remain standing. The less severe cases were discarded after the aircraft impact results were compared to observed events.

In other words, the middle cases did not produce the results from the videos. They used the videos as ground truth to calibrate the model inputs.

Are you saying that the videos don't give an accurate impression of what happened?

[Kevin Fenton]

109. 10 out of 10 for actually having a look at the document

But 0 out of 10 for reading comprehension.

The quote is:
"Upon a preliminary examination of the middle cases, it became clear that the towers would likely remain standing. The less severe cases were discarded after the aircraft impact results were compared to observed events."
NIST used three sets of cases - less severe, base and more severe. The quote clearly says that the less severe cases (one for each tower) do not match the observed events (for example the plane approached the tower at a different speed and angle). It does not say that the middle (aka "base") cases do not match the observed events. They do.

In fact, in addition to the numbers for the base cases being more accurate than those for the severe cases, the base cases also correspond more closely to what really happened:
In the base cases "the overall agreement with the observed damage was very good. The agreement for Cases B and D was slightly lower."
NIST report, p. 116/166

Are you saying that the videos don't give an accurate impression of what happened?

[hack89]

113. So if I understand correctly...

after deliberately falsifying the research they boldly stated in the document that it was falsified? Do you understand why this makes me believe that perhaps the real issue is that you and I don't really understand how modeling of such things is done?

The end result as I see it is:

1. The input variable are within the range of possible values - a good part of the rest of the document shows in exhausting detail how they were derived. Each can be defended as happening in the real world.

2. The final results match what happened on 9/11.

Now if you can show me why the input variables are beyond the realm of possible, perhaps you have something.

[Kevin Fenton]

118. If you stopped overstating...

... I just might get worried you had a point.

"after deliberately falsifying the research they boldly stated in the document that it was falsified?"
No, after deliberately fudging the research they boldly stated in the document that it was fudged.

"The input variable are within the range of possible values"
No, they aren't for the severe case.
Two examples:
(1) The two best studies for the speed of United 175 came up with figures of 503 mph (MIT) and 497 mph (NIST complex motion analysis). NIST's severe case used a speed of 570 - that is not within the range of possible values.
MIT study: http://web.mit.edu/civenv/wtc/PDFfiles/Chapter%20III%20...
NIST's complex motion analysis can be found in NIST NCSTAR1-2 on p. 155/269.

(2) In the severe case NIST increased the amount of combustibles in the towers from 4 lb/ft2 to 5 lb/ft2. However, we know that the combustibles loading was only 4 lb/ft2, because:
(a) This is the figure you get when you count it:
"NIST estimated the combustible fuel loading on these floors to have been about 4 lb/ft2 (20kg/m2), or about 60 tons per floor. This was somewhat lower than found in prior surveys of office spaces. The small number of interior walls, and thus the minimal amount of combustible interior finish, and the limited bookshelf space account for much of the differences. While paper in the filing cabinets might have been significant mass, it did not burn readily due to the limited oxygen available with the drawers."
NIST main report, p. 77/127

(b) In computer simulations, the fires spread at a rate corresponding to a combustibles loading of 4 lb/ft2:
"The fact that the simulated fires encircled the building in roughly the same amount of time as the actual fires supported the estimate of the overall combustible load of 20 kg/m2 (4 lb/ft2). Simulations performed with higher loads required a proportionately longer amount of time to bring the fires around to the southeast because of the fact that the burn time was roughly proportional to the fuel mass in the oxygen-liminted interior of the fire floors."
NIST NCSTAR 1-5, p. xlvi/48

The extra 1 lb/ft2 works out at over 200 tons across all the fire floors. An extra 200 tons is not "within the range of possible values". It wasn't there and we know it wasn't there.

[hack89]

121. Well, then we will just have to wait for subsequent studies..

to see who is right, won't we? If the science is bad it will be revealed. What will be your excuse when it comes to the same conclusion?

By the way, this study was posted for public comment - did you find any real engineers that agreed with you?

[Make7]

63. You may not be accounting for all of the actual load dynamics.

Kevin Fenton wrote:

In NIST's base case the planes destroy approximately 10.5% (WTC 1) and 13.5% (WTC 2) of the gravity load-bearing structure, so what happened to the rest of the towers?

The redistribution of the load that was carried by the destroyed and damaged load-bearing elements needs to be considered. Stating the reduction in load bearing capacity simply by calculating the percentage of destroyed columns can in no way be considered an accurate measure of the dynamics involved. Where do the loads go from the destroyed columns? They are certainly not evenly distributed among the remaining columns as would be implied in a before/after percent comparison.

I think the majority of the loads from severed columns will transfer to the columns close to the destroy/damaged ones. This additional load may at some point overload the ability of those columns to carry the newly redistributed load in addition to its normal load - causing failure and further redistribution of the loads, etc., etc. The reduction in strength of any columns due to heating by the fires also needs to be taken into account.

Many of the variables involved are still unknown - I don't feel that your percentage of destroyed load-bearing structure figures are representative of the actual events in question. It may be close to the reduction in load immediately caused by the airplane impacts, but then of course we all know that the buildings did not collapse at the time of the impacts.

- Make7

[Kevin Fenton]

66. Fires, redistribution

I do not claim that the figures I gave are representative of the whole scope of the damage. I specifically admit that they should be further adjusted to take into account both the fires and any problems with load redistribution.

"The reduction in strength of any columns due to heating by the fires also needs to be taken into account."
Yes, it certainly does. The fires would certainly further weaken the structures. However, I am suggesting that we should first estimate the impact damage (because it was first and because it is much easier to estimate) and then move on to the fire damage. Depending on how hot the fires were, they could cause more damage to the building's gravity load-bearing capacity than the actual impact damage.

"I think the majority of the loads from severed columns will transfer to the columns close to the destroyed/damaged ones."
(1) I would put it like this:
Although the building was able to redistribute loads from damaged/destroyed columns, a large amount of asymetric damage would have overwhelmed this ability, regardless of the safety factor.
For example, even if the building's safety factor was 3, then removing the core in its entirety would surely destroy the building (i.e. local collapse, at least, would ensue), even though the core only carried about 50% of the gravity loads and the safety factor was still 1.5.

(2) If the majority of loads from the severed columns were transferred to the columns close to them, then (assuming that the collapse is due to the extra loads here and not some weak point in the flooring, as is claimed for example by Eager, Usmani and (sort of) NIST) then these columns should fail first and this should be visible. I see no such failure in the north side of the North Tower or the south side of the South Tower, the areas most clearly damaged by the aircraft. Indeed, NIST claims that the towers failed elsewhere - the south side of the North Tower and the east side of the South Tower. Further, the the South Tower clearly falls to the east, indicating that it was not columns on the south side of the perimeter that failed first.

Misc:
I would divide the collapse initiation theories into two groups: (a) the structure was generally overwhelmed, (b) the structure failed because of some weak point. Words cannot express how much I doubt (a), whereas I think (b) is much more likely (although I don't buy it yet).

What do you think the safety factor was?

Have you seen Loose Change yet?

[Make7]

103. failures - local & global

Posted by Kevin Fenton:

I do not claim that the figures I gave are representative of the whole scope of the damage. I specifically admit that they should be further adjusted to take into account both the fires and any problems with load redistribution.

Okay. My response was mostly to suggest that the other pertinent factors not be omitted - they seemed to be absent in the post to which I replied. But it looks like we are both on the same page concerning this.

Posted by Kevin Fenton:

"The reduction in strength of any columns due to heating by the fires also needs to be taken into account." - Make7

Yes, it certainly does. The fires would certainly further weaken the structures. However, I am suggesting that we should first estimate the impact damage (because it was first and because it is much easier to estimate) and then move on to the fire damage. Depending on how hot the fires were, they could cause more damage to the building's gravity load-bearing capacity than the actual impact damage.

Okay - I think taking things one step at a time is a reasonable approach, but I'm not sure how easy it is to estimate the impact damage inside the building. I haven't really even made a guesstimate on that one, and I'd have to do some research into it before I could.

Posted by Kevin Fenton:

"I think the majority of the loads from severed columns will transfer to the columns close to the destroyed/damaged ones." - Make7

(1) I would put it like this:
Although the building was able to redistribute loads from damaged/destroyed columns, a large amount of asymetric damage would have overwhelmed this ability, regardless of the safety factor.
For example, even if the building's safety factor was 3, then removing the core in its entirety would surely destroy the building (i.e. local collapse, at least, would ensue), even though the core only carried about 50% of the gravity loads and the safety factor was still 1.5.

(2) If the majority of loads from the severed columns were transferred to the columns close to them, then (assuming that the collapse is due to the extra loads here and not some weak point in the flooring, as is claimed for example by Eager, Usmani and (sort of) NIST) then these columns should fail first and this should be visible. I see no such failure in the north side of the North Tower or the south side of the South Tower, the areas most clearly damaged by the aircraft. Indeed, NIST claims that the towers failed elsewhere - the south side of the North Tower and the east side of the South Tower. Further, the the South Tower clearly falls to the east, indicating that it was not columns on the south side of the perimeter that failed first.

(1) I agree with that.

(2) I guess I could have worded my argument better - I was not trying to outline a specific collapse scenario - only that load redistribution would occur and would have an effect on the load-bearing capacity of the building. The structure of the Towers was complicated - the factors involved in a non-controlled demolition collapse would likely encompass different local failure mechanisms up to the point of collapse initiation. There are many reasons that columns might have failed, simple gravity load redistribution being just one of them.

The North Tower collapse seemed to have started with the core, so I don't know that any perimeter column failure due to impact induced gravity load redistribution would necessarily be visible.

Some of the loads from the missing perimeter columns on the eastern portion of the south face would be redistributed to columns on the southern portion of the east face as well. The missing south face columns would not be the point of failure - the building had been standing quite some time with them gone - the failure would be at the point of the structure where it was unable to continue to redistribute the load effectively when some portion of it failed.

One more quick thing about the South Tower: if you watch a close up of the north face at the collapse initiation, you can see the perimeter columns begin to fail at the east side and then more and more columns start to fail towards the west side. This happens quite rapidly, stepping through frame by frame makes it easier to see.

Posted by Kevin Fenton:

Misc:
I would divide the collapse initiation theories into two groups: (a) the structure was generally overwhelmed, (b) the structure failed because of some weak point. Words cannot express how much I doubt (a), whereas I think (b) is much more likely (although I don't buy it yet).

What do you think the safety factor was?

Have you seen Loose Change yet?

I don't know if a failure due to the structure being generally overwhelmed is even possible in this case. I think most large failures of complex systems usually boil down to one, or a very small number, of weak points initially failing causing a chain reaction of failures in other elements. In fact, that almost sounds like it could be a definition for progressive collapse.

"Progressive collapse denotes an extensive structural failure initiated by local structural damage, or a chain reaction of failures following damage to a relatively small portion of a structure. This can be also characterized by the loss of load-carrying capacity of a relatively small portion of a structure due to an abnormal load which, in turn, triggers a cascade of failures affecting a major portion of the structure." - Source

The safety factor? I'm not sure, I remember reading some load analyses done by NIST quite a while ago. I'll have to dig it up and put my thinking cap on to come up with something reasonable.

I saw the first edition of Loose Change many, many months ago - according to my computer, I downloaded it last July. I watched part of the second edition on Google Video a while back but never made it the whole way through. Was there anything in LC2 that I may not have seen elsewhere already?

- Make7

[Kevin Fenton]

111. Perimeter columns

How many perimeter columns failed on each side?

WTC 1
"35 exterior columns severed, 2 heavily damaged"
NIST, p. 22/72

WTC 2
"33 exterior columns severed, 1 heavily damaged"
NIST, 41/91

These are for the severe case, so they need to be cross-checked against what NIST has for the base case and the photos, but they should be more or less correct.

Two issues to consider:
If a column is damaged, what portion of its load-bearing capacity remained?
How about:
Heavy damage: 25% left
Medium damage: 50% left
Light damage: 75% left
How should the gravity load-bearing capacity be split between the core and the perimeter?
"The dense array of columns along the building perimeter was to resist the lateral load due to hurricane-force winds, while also sharing the gravity loas about equally with the core columns"
NIST, p. 6/56
How about 50/50?

The 50% on the perimeter should be split evenly between the 236 columns there, but the core columns were all different sizes (and were transitioning from box columns to I beams on the impact floors), so it's going to be more difficult there.

Is the load-carrying capacity of the columns a function of their cross-sectional area? If so, the 50/50 distribution could be checked against it.

In no particular order:
(1) I thought the images in Loose Change were good, not the commentary. I haven't seen the 1st version, so I don't know about the differences between them.
(2) Would you have a picture or video of the north face of the south tower showing the buckling? I had one, but seem to have misplaced it. What floor did they start to buckle on?
(3) If the core in the North Tower did fail first, then perimeter column failure may well not be visible. However, NIST rather implied that it wasn't the core that failed first.

[simonm]

7. If it walks like a duck..

it doesn't take long to figure out that thermite is not used for CD

Undoubtedly, any number of heat producing, relatively non-explosive reactants that are more sophisticated and compact than thermite exist, but for the purposes of initial analysis, and determining the boundary conditions, it was felt that thermite was a reasonable first choice.

http://www.physics911.net/thermite.htm

no witnesses to a massive effort to wire up the towers. Most importantly, no plausible scenario has been suggested - why can't someone tell me where the explosives were placed and how many tons of explosives were used?

Marvin Bush was the director of Securacom who was responsible the the World Trade Center building security on 9-11-1. On Thursday before 9-11-1, the bomb sniffing dogs were withdrawn. On the weekend before 9-11-1, unidentified technicians swarmed over the twin towers and „rewired” them. This would have been an ideal time without security to plant bombs for a controlled demolition. Margie Burns has written extensively about Marvin Bush (search on the internet). Barbara Bush in a book has confirmed that her son Marvin was standing close-by the World Trade Center on 9-11-1 at the time of the attacks, as if to supervise.

[dailykoff]

9. Tomorrow and tomorrow and tomorrow

he'll repeat that same damn talking point, even though you and many others have repeatedly explained when, how, and where the charges were likely placed.

[hack89]

10. No, they never have..

but perhaps you can tell me:

1. how many tons of explosive

2. what type of explosives

3. where were the placed

4. How long did it take to put them in place

Lets get it on record - it will help with future threads. Unless of course you don't want to be on the record?

[dailykoff]

13. I can tell you what I think

based on the information currently available to me:

1. Depends on the types of explosives used;

2. You tell me, since you're obviously dying to;

3. Attached to the core columns, accessed mainly through the elevator shafts;

4. 500 charges/20 men x 1/2 hour/charge = 12.5 hours.

Anything else?

[hack89]

15. 220 floors in 12 hours equals 3 minutes a floor

It would take you that long to walk from one end to the other.

How many men to move 5 tons of explosives per floor without being seen.

How many spools of det cord?

How men invisible trucks full of explosives?

How long to expose the columns and do a perfect repair job afterwords so no one would notice.

How do you route and hide massive bundles of detcord that are miles long.

As usual, you are a little light on the details.

[dailykoff]

17. There's a top-secret invention that moves stuff at high speeds

from floor to floor. I think it's called the elevator.

[hack89]

19. So it took 3 minutes per floor? If you say so! nt

[dailykoff]

20. I said "1/2 hour/charge." You said 3 minutes. (n/t)

[hack89]

22. 220 floors divided by 750 minutes = ? nt

[dailykoff]

24. Try reading more carefully.

I said 500 charges, not 220 floors.

[hack89]

26. So how many floors had explosives?

were the rest pancaked?

[dailykoff]

30. Enough to blow the frames apart, obviously.

Probably four charges every other floor would do it. That's 440 charges, leaving us 60 extra to play with.

Give me the specs and I'll try to be more specific.

[hack89]

32. Lets think about this...

47 core columns and a couple of hundred perimeter columns.

One charge per side to account for the squibs leaves nothing for the core.

Are you saying that severing a couple of core columns is enough to bring down the building? You would think 40 or so core columns left intact would be enough - I guess the WTC weren't as strong as we thought.

[dailykoff]

34. I thought you didn't believe in squibs?

And who said anything about severing individual columns? The charges were no doubt powerful enough to take out several at once. As you keep pointing out, this was no ordinary demolition.

[hack89]

36. But you do ..

and you are kidding about the charges aren't you? You do know how shaped charges work don't you?

I don't believe in squibs - I am merely applying standard CT mythology to your answer. Do you think there were squibs?

[dailykoff]

37. You brought up squibs, not me. So forget them

for the moment and tell my why my figures are wrong. (n/t)

[hack89]

40. There aren't enough charges..

you would need to sever more of the core columns - and you would need to use shaped charges.

Why wouldn't 48 shaped charges on the first floor work? Take out all the core columns and stand back and watch the tower fall?

[dailykoff]

42. Okay let's double the charges

and use 40 men to wire both towers in 12.5 hours. Now we have 8 charges every other floor, 4 on a side. Bingo.

p.s. first floor charges would topple the buildings.

[hack89]

44. Topple?

gravity works straight down - where are the lateral forces? All fore columns at once means the initial movement of the tower is straight down and once it starts nothing will stop it.

[dailykoff]

46. We covered lateral loads last week. (n/t)

[hack89]

48. Oh yea - the wind blew it over!

I forgot.

[dailykoff]

54. p.s. here's the distribution:

Placing 24 charges per floor on every fifth floor would take:

24 charges x 21 floors = 504 charges/20 men x 1/2 hour/charge = 12.6 hours per tower.

[hack89]

55. What is involved in placing the charges?

does the 30 minutes include the following:
1. removing obstacles, ceilings and walls to expose the columns.
2. making perfect repairs to conceal the columns.

Who was responsible for stringing miles of det cord through the towers? How long did that take? Where were they terminated?

What was the weight of each charge?

What was energy of the total charges? Was it adequate to eject steel beams and create the dust cloud?

I don't necessarily expect you to personally know every answer, especially with the more technical questions, but considering it has been four and a half years since 9/11 surely someone in the 911 research community has produced a paper with the answers. Links will be fine.

[dailykoff]

56. !. No repairs necessary;

2. Little or no wall removal necessary, depending on how the elevator shafts were finished, and in any case punching through sheetrock is not exactly difficult;

3. No det cord necessary with radio-controlled detonation;

4. Weigh of each charge--I'm not in the business of blowing things up so I'll leave that to your imagination.

[hack89]

57. You are not in the business of CD ..

yet you are so certain that radio-controlled detonation would work - what makes you so certain the the signal would penetrate so deep into a steel framed building? And how do you prevent interference in such a signal rich environment?

So there was no thermite on the perimeter walls - you disagree with the OP?

Again, you expect me to believe that three perfect demolitions were done with untested materials and procedures - I don't buy it.

[dailykoff]

58. But the defense industry is

in the CD business, and I'm one of the lucky people who get to pay billions and billions annually so they can test themselves silly.

[hack89]

59. No they are not ...

military demolition has nothing to do with CD - they blow stuff up with no finesse, precision or regard for collateral damage. And they also have problems with electronic interference which is why they use det cord for demolition.

[dailykoff]

62. Military demolition is demolition

and 9/11 was no miracle of finesse. Incidentally I said the "defense industry," not the military -- they are similar, but not identical.

[hack89]

71. So now you merely have to provide some proof. nt

[dailykoff]

72. The evidence is manifest.

Open any thread and look at any photograph. I'm sorry to have to tell you this, but the cat is out of the bag.

[hack89]

73. Nothing beyond google engineering?

So show me the pictures of the wireless detonators please.

[simonm]

106. Field Manual: Explosives and Demolitions - US Army

2-9 Premature Detonation by Induced Currents and Lightning

a. INDUCED CURRENTS. The premature detonation of electric blasting caps by induced curret from radio frequency signals is possibl. Table 2-1 showing the minimum safe distance in respect to transmitter power, indicates the distance beyond which it is safe to conduct electrical blasting even under the most adverse conditions. This table applies to operating radio, radar, and television transmitting equipment. Mobile type transmitters and portable transmitters are prohibited within 50 meters of any elctrical blasting caps or electrical firing system. If blasting distances are less than those shown in table 2-1, the only safe procedure is to use a nonelectric system, which cannot be prematurely detonated by RF currents. If however the use of the electric systme is necessary, follow precautions given in TM 9-1300-206. See also AR 385-63. Caution. If electric blasting caps are to be transported near operating transmitters or in vehicles (including helicopters) in which a transmitter is to be operated, the caps will be placed in a metal can, the cover of which must be snug fitting and lap over the body of the can to a minimum depth of one-half inch. Caps will not be removed from container in proximity to operating transmitter unless the hazard has been evaluated and estimated to be acceptable.

b. LIGHTNING. Lightning is a hazard to both electric and nonelectric blasting charges. A strike or a nearby miss is almost certain to initiate either type of system. Lightning strikes, even at remote locations, may cause extremely high local earth currents. The effects of remote lightning strikes are multiplied by proximity to conducting elements, such as those found in buildings, fences, railroads, bridges, streams, and underground cables or conduct. Thus, the only safe procedure is to suspend all blasting activities during electrical storms and when one is impending.

c. ELECTRIC POWER LINES. Electric firing should not be performed within 155 meters of energised power transmission lines. When it is necassary to conduct blasting operations at distances closer than 155 meters to electrical power lines, nonelectric fire systems should be under or the power lines deenergized (AR 385-63).

table 2-1: ______________________________________________________________ Average or peak ! Minimum distance transmitting power ! to transmitter(meters) ______________________________________________________________ ! 0-30 ! 30 30-50 ! 50 50-100 ! 110 100-250 ! 160 250-500 ! 230 500-1000 ! 305 1000-3000 ! 480 3000-5000 ! 610 5000-20000 ! 915 20000-50000 ! 1530 50000-100000 ! 3050 _______________________________!______________________________

2-10. Methods of Use

Of all firing systems for explosives, a detonating cord firing system is probably the most versatile and in many cases the most easily installed. It is especially applicable for underwater and underground blasting because the blasting cap of the initiating system may remain above the water or ground.


https://www.totse.com/en/bad_ideas/ka_fucking_boom/demo...

[Bouvet_Island]

116. All military and covert operations in all countries use

det cord in all cases? *All* experiments with radio controlled explosives were flawed, because of the same the same reason for which we turn off cell phones on a planes? I mean several airliners have quit that, there aint a single proven case, I believe even not in hospitals with new cellphones. Are you aware that all electronic equipment have to pass test on their emission of emp, and that it is trivial to shield against it? I mean we all know how there are a lot of, say, accidental three sentence morse beep signals on FM 99.6 all the time - Picking any signal below 5 sentences would be irresponsible ... And clearly it is impossible to get the same signals that will pass through our entire atmosphere into a building that is 95% air. I mean clearly noone could get cellphone reception in the wtc ...

Hey but wait, what about if they had a repeater in each shaft? or used the entire structure as an antenna?

I have no idea what part of your body you are pulling your empty rethoric out of. I believe your real world must still be left in the 50s or 60s. The two specific strategic problem with electronic interference the US army have is emp from nuclear weapons, and the problem of the enemy possibly getting hold of frequncy and codes through espionage, or jamming the signal. This doesn't mean special forces or engineer troops could do things you wouldn't imagine. Just tacking a cell phone to a bomb is highly effective as a lot of Iraq vets can attest to, and would likely work for a demolition where it wasn't important to have a very clean result. It would not be subject to premature explosion. Induced current is a problem when you use long wires and unsophisticated mechanisms, not on, say, the weapons carried on a helicopter which include blasting caps ... Obviously you can get something with a little bit more precise timing. Military warhead detonation series are timed in miliseconds or less or how to put it ... And the russian ones get speeds of 700 km/h under the ocean ... The Israelies are already using chemical lasers to shoot down missiles in practical applications, they have like Israeli lego of it ... Students can genetically engineer species ... It is not beyond us to remote explosives in roughly precise manner.

You seem to me to be a complete hack at this. Do you have any relevant background? Any work experience in science? You never answered that question.

[hack89]

117. Instead of the hysterics, how about some proof?

the fact that all you have is personal attack says it all as far as I am concerned.

[Bouvet_Island]

122. What you have asked for a lot of times in this thread

is a more detailed hypothesis. I don't have to defend any particular theory or prove anything to you beside my two points:

1. Your theory and points in the post I replied to are compeletely wrong. You are trying to conjure up some technical or organizational impossibility of there being explosives inside the WTC towers on 9/11. An important point is that "it takes weeks", while your own opinion is that it took nothing but plane impacts and fires. You are making up facts to support your point, and picking bad candidates for this that is easy to disprove.

2. You are a hack. This is neither a personal attack or hysterical, you evidently don't know much about what you are talking about like you were an expert in it. An analysis that says that conspirators *must* follow conventions or do stuff a certain way, it is flawed at start for every type of crime and when discussing the theory of a crime more radical and crazy then possibly ever before in Human history, it is as moot a point as can be, it is nonsensical. Why would the possible conspirators even want the WTC to look like "normal" controlled demolition? If you believe it is ok to call yourself reality based and your opponents crazy, it also have to be ok to be called a hack when the truthfullness of this can be proven.

I'd be happy to discuss these theories with you and present you with some of the pieces I find curios, but first, please state how you view what happened that day. What theory do you support? How do you substantiate it?

[hack89]

124. If you say so. n/t

[Bouvet_Island]

131. I take it

that is as close a person like you come to ever admitting being wrong about something.

I still am curious about your own position. I think it'd be more interesting to turn the debate the other way round, you could explaing what happened and give a theory about that and we could see if we were able to pick it apart. With the confidence you have in your own version, it surely would be no problem for you to provide it for our enlightenment? Or are you just a quack of sorts, selling medicine that you wouldn't administer to yourself?

[hack89]

132. I admit nothing except..

there was no point in continuing the conversation.

[Bouvet_Island]

136. A petty it wasn't a success story.

I still am interested in any substance to your own views. I'd like you to step down from your flying carpet.

[Bouvet_Island]

12. You obviously have not read

up on what your opponents viewpoints really are.

Your insinuations are rubbish. And your premise is completely false, first thermite are proven capable of taking down structures in military applications, and second there are for example no other cases of large steel structures falling from fires combined with unsubstantial structural damage, as well. This isn't proof, it hardly is insinuation. Again your theory is that no explosives at all was necessary to pull the greatest CD of all times, your argument that it would be impossible for people with years of planning and access to expertize to accomplish what you mean would necessarily happen by accident.

Your thesis that people would have to do stuff a certain way or use standard industry practice is silly, when realizing you are nothing like an expert in demolition. You don't even seem to have made any effort to understand the argument you are trying to disprove, and you use your own ignorance as an argument in itself, saying google really doesn't cover your base. Did you read all the results on thermite? And would information on military use of thermite necessarily be in gooogle?

You are simply a hack, always arguing your favourite strawman of the day.

[hack89]

28. OK

So this CD was planned during the Clinton administration? Explains why the democratic party won't touch the issue with a ten foot pole.

[dchill]

110. "There is no evidence..."

"no evidence of CD,... no evidence of explosive residue..." Of course not. It was all cleaned up and illegally hauled away before any on-scene investigation was done. Why do you ignore all the logical questions that inquisitive minds want answered? There is no evidence of anything about 9/11 except that much evidence was covered up. If that doesn't make you curious, then I don't know what would.

If someone wanted to make sure those 3 buildings came down, might not a little "overkill" be in order - especially if you're working from the Pentagon?

"thermite is not used for CD." - It might be just the thing to melt steel.

http://www.ilpi.com/genchem/demo/thermite/index.html

I Googled that.

[hack89]

115. You are wrong...

about the forensic evidence - what about the dust that covered all of lower Manhattan? That overkill would involve hundreds of tons of explosives, which in turn would leave plenty of residue in the dust as it was violently ejected from the towers. I have never understood why some enterprising 9/11 researcher never went to New York and collected a bunch of dust and have it tested - unless they did and didn't get the results they expected.

In any case, here are the results of an exhaustive analysis of the WTC dust by a commercial lab for litigation purposes - there was no evidence of explosives.

http://www.nyenvirolaw.org/WTC/130%20Liberty%20Street/M...

The fact that thermite can melt steel is not in question - the issue is whether it is used for CD. You will not find any examples. But why would they use thermite when high explosive shaped charges are designed specifically for CD? There is no advantage to using thermite.

You expect me to believe that the largest CD ever done was executed flawlessly on three building using untried techniques - I don't buy it.

[DemInDistress]

6. more thermite cutter charges caught on tape..

http://www.terrorize.dk/911/wtc2dem3 / scroll down ..

another look.. Video: 911.wtc.2.demolition.east.5.enl.slow.2.wmv
what are those white flashes? glint of the sun? bet the debunker's howl tonight !!

[mirandapriestly]

8. those sparks are very "tell tale"

it's like some welder guy is up there cutting the steel - but, instead it is just a charge, possibily containing thermite...

[Harald Ragnarsson]

51. That corner the thermite is burning in

Is where the collapse begins at. There are other videos that keep recording right up until the building disintegrates. It buckles and starts to fall at that corner. Obviously this thermite melting a corner support which initiated the whole collapse sequence.

This can only mean that the planes were guided to particular spots on the building.

I remember in the days after 911, I heard 1000 times that Tower one was hit correctly, but tower 2 was not. I mean, they wanted to hit the towers, what did they care if it was in a particular spot or not? I think the bit about tower 2 not being hit correctly was a bit of the true story coming out. It was not hit exactly where it was supposed to be and it caused problems during the demolition where they had top think on their feet. Hence the helicopter appearing to be shooting rockets at the top of tower 2 before it collapsed.

[LARED]

60. Another equally valid comparison

Hummmmmmmmm!!!!

[Name removed]

61. Deleted message

Message removed by moderator. Click here to review the message board rules.

[mirandapriestly]

68. You're one of those

unobservant types.

[LARED]

69. Quite the contrary

I observed that the two pictures I posted have more in common than the two pictures posted in the OP. Mine are completely unrelated and so are they.

[mirandapriestly]

76. look closely (me thinks you already have)

and OBSERVE the sparks in the wtc pic and the SPARKS in the thermite pic, wtf else are those sparks going to be from than something that is cutting that steel?
This reminds me of my husband, I told him to clean all the junk out of the garage and he was standing there amidst three feet of old papers & broken stuff and he said "what "junk" are you talking about?"

[LARED]

93. Yes, I looked closely

I see the material leaving the WTC as a molten material spilling out of an opening. To me they do not appears as sparks.

[mirandapriestly]

95. whatever it is, it's existence gives these photos more

in common than the photos you used.

[LARED]

96. Perhaps

My point was that things can look alike but be very different things. So equating a demonstration of thermite reacting is conclusive of nothing.

I could show a a picture of an arc welder or oxy/acetylene torch and it would also look somewhat similar to the thermite reaction, but you don't see me humping the notion that someone was using a blowtorch in the building.

[mirandapriestly]

100. I never want to

see you humping that or any other notion. I see your point, you should have just said that in the first place. It's actually sort of a good point, but the picture is not the only reason people think thermite. The extreme heat and the sulfur residue for example and granular displacement or something like that, I can't remember. The fema report and the NYT stated those were unanswered questions about the steel, can't remember exactly what they said, but I think that is what got people onto thermite initially.

[LARED]

105. Sulfur residue is a red herring in my opinion

Gypsum (the stuff wall board is made out of) is chock o block fill of sulfur.

http://webmineral.com/data/Gypsum.shtml

[mirandapriestly]

119. But gypsum board is used for fireproofing

isn't it? so why would that be the cause of the sulfur?

[hack89]

126. It was ground up by the collapse ...

there was calcium sulfate dust throughout the rubble pile

[Bouvet_Island]

123. LARED,

what is the reaction that will "liberate" that sulphur? I was under the impression Gypsum wasn't very reactive ...?

[AZCat]

120. That's not junk...

It's just stuff that hasn't found a use yet!

(says a long-time packrat)

[mirandapriestly]

129. heh heh nt

[MrSammo1]

94. It's great to see just how

desperate government shill like yourself are getting.

I can assure you that most of the forumers here understand what you are and simply ignore your nonsense.

[hack89]

98. So why don't you ignore us too? nt

[MrSammo1]

101. Ahhhhh.........

Another shill speaks up!

Because it's more fun pointing you out to the class!

[file83]

134. If there is anything more pathetic than one of us lowly...

..."9/11 truth seekers", it's a person that spends day and night trying to support the 9/11 Commission Report.

[MrSammo1]

114. It's more fun

pointing you out!

[hack89]

125. So much fun you had to do it twice? nt

[Clarkent]

127. A collection of links about the metal

A collection of links about the metal:

Last spring, the standards institute found the first photographic evidence on the east face of the south tower that a single floor — with its lightweight support system, called a truss — had sagged in the minutes before it started collapsing. Now, detailed analysis of photos and videos has revealed at least three more sagging floors on that face, said William Pitts, a researcher at the institute's Building and Fire Research Laboratory.

In addition, Dr. Pitts said, sudden expansions of the fires across whole floors in each tower shortly before they fell suggested internal collapses — burning floors above suddenly giving way and spreading the blaze below.

Finally, an unexplained cascade of molten metal from the northeast corner of the south tower just before it collapsed might have started when a floor carrying pieces of one of the jetliners began to sag and fail. The metal was probably molten aluminum from the plane and could have come through the top of an 80th floor window as the floor above gave way, Dr. Pitts said.

"That's probably why it poured out — simply because it was dumped there," Dr. Pitts said. "The structural people really need to look at this carefully."

http://www.nytimes.com/2003/12/03/nyregion...HLXBQn0ZEP...

NIST pg 43 Section H.9 App H Vol 4
Starting at around 9:52 a.m. a molten material began to pour from the top of the window 80-256 on the North face of WTC 2. The material appears intermittently until the tower collapses at 9:58:59. The observation of piles of debris in this area combined with the melting point behaviors of the primary alloys used in a Boeing 767 suggest that the material is molten aluminum derived from aircraft debris located on floor 81.

NIST H-7-2
Molten Material
It has been reported in the FEMA report (McAllister 2002) as well as in the media that what appeared to be molten metal was observed pouring from the north face near the northeast corner. This is the area where the sustained fires were seen. Video records and photography indicate that the material first appeared at 9:51:52 am and continued to pour intermittently from the building until the time of the collapse. Some of that material can be seen falling in Fig. H-21. Close up video and photographs of the area where the material is pouring from have been examined and show that it is falling from near the top of window 80-256. The most likely explanation for this observation is that the material had originally pooled on the floor above, that is 81, and that it was allowed to pour out of the building when this floor either pulled away from the outer spandrel or sank down to the point where the window was exposed. The fact that the material appears intermittently over a several minute period suggests that the floor was giving way bit by bit

The composition of the flowing material can only be the subject of speculation, but its behavior is consistent with it being molten aluminum. Visual evidence suggest that a significant wreckage from the plane passed thought the building and came to rest in the northeast corner of the tower in the vicinity of the location where the material is observed.
Much of the structure of the Boeing 767 is formed from two aluminum alloys that have been identified as 2024 and 7075 closely related alloys. These alloys do not melt at a single temp, but melt over a temp range from the lower end of the range to the upper as the fraction of the liquid increses. The Aluminum association handbook lists the melting point as roughly 500C to 638 C and 475 C to 635C for alloys 2024 and 7075 respectively. These temperatures are well below those characteristic of fully developed fires (ca 1000C ) and any aluminum present is likely to be at least partially melted by the intense fires in the area.

http://wtc.nist.gov/progress_report_june04/appendixh.pd...

But the fires continued to burn. Black smoke poured from shattered windows on floor after floor, fresh oxygen sucked in from the gaping holes caused by the impacts. In the northeast corner of the south tower's 80th floor, where office furniture had been shoved by the plane, the fire burned so hot that a stream of molten metal began to pour over the side like a flaming waterfall.

The apparent source of this waterfall: molten aluminum from the jet's wings and fuselage, which had also piled up in that corner. Within minutes, portions of the 80th floor began to give way, as evidenced by horizontal lines of dust blowing out the side of the building. Seconds later, near the heavily damaged southeasterly portion of this same floor, close to where the aircraft had entered, exterior columns began to buckle.
http://www.meehawl.dyndns.org:1080/Webstor...ort%20Says...

A photograph leaked from the ASCE-FEMA investigation shows a stream of what appears to be molten aluminum exiting from the northeast corner. This would indicate that what was left of the aircraft when it reached the north end of its travel was massive enough to have destroyed at least one floor.
http://www.scieneering.com/wtc_update.html

Finally see Melted aluminum earler at 9:27 in a area very close to the other liquid
http://wtc.nist.gov/NISTNCSTAR1-5A_chap_9-AppxC.pdf
See fig 9-32
9:27 78th floor

Enjoy

[zforce]

128. Color?

Do you know what color Molten Aluminum is?

[Harald Ragnarsson]

137. Whoever wrote that article is full of crap

Molten aluminum looks like mercury. It is silvery in color, not orange/red like the slag shown pouring out of the corner of the WTC prior to collapse.

That someone attempts to say these two metals look alike when molten is a deliberate attempt to "mis-inform" or as it used to be known, LIE.

[dailykoff]

130. Sagging floors? Tell me you're joking.

The web trusses in the floors were essentially nonstructural and had nothing to do with the building failures. Neither did the breaking windows.

To pretend they did is a "post hoc ergo propter hoc" fallacy and shows either terrible reasoning or outright fraud. Floors may have "sagged in the minutes before it started collapsing," but that isn't what made it collapse.

[Dancing_Dave]

133. They should make a scale model of the WTC

And apply the Thermite treatment.

That would give us a clear scientific replicable experimental demonstration.

[file83]

135. Or just remove the sections that were destroyed by the aircraft

and see what happens. Those models would NEVER collapse. NEVER.

[mirandapriestly]

138. More Thermite indications?

Thermite makes a bright,white flame with white smoke, the picture below looks like it has both. What could be another explanation for both black and white smoke?


This is a description from NIST of the flames


Below is a description of a thermite reaction. white flame which turns to orange, that is something that I have seen in 9-11 videos quite often. What else could be the explanation?:

http://www.allatoms.com/thermitepicpage.htm
The action started with the characteristic white flame of burning magnesium, but the flames soon exploded in orange and yellow. We then watched as orange liquid flowed from the bottom of the pot into a coffee can filled with water. The still orange-hot iron could be observed rumbling around in boiling water! After finally ridding itself of considerable energy, we were