Question for the learned company...

[TraneWreck]

Howdy,

I have read these forums for a while and greatly appreciate the wisdom and expertise of the members. This is my first post here, and I would just like some answers to a couple of questions:

First, in a draft paper by NIST titled, Mechanical and Merallurgical Analysis of Structural Steel (I just learned I can't post links yet, sorry), NIST claims that their analysis of the paint cracking only established a maximum temperature of over 250C in a couple of places. I realize that NIST adds the caveat that the tested metal, both perimeter and core columns, was hardly representative.

My first question based on this paper is why NIST wasn't able to find samples that exhibited higher temperatures. I surmised that much of the paint, like the fireproofing, was blasted off where the temperatures were the highest, but this is hardly a scientific theory. Second, what was the process by which NIST estimated the heat of the fires. I read a loooooong paper from NIST about the fires in both buildings, but it was largely about where and how it traveled, I was unable to find their method of establishing the max temperature. The usual stellar debunking sites (911myths, debunking911, etc) didn't have anything about that either.

The second main point I've been having trouble finding information on is why, when calculating the heat, the maximum burning temperature of jet fuel, 980C, is relevant, whereas the open-air burning temp, 287.5C, is not. Basically, I don't understand what "open-air" means. I always assumed the heat in the WTC fires was largely a result of the bunches of crap (tables, desks, chairs, carpet...) that cought on fire that escalated the temperature, but I don't really understand the mechanism, nor was I able to find out much about it.

Anyway, sorry for the length and any answers or nudges in the right direction will be greatly appreciated.

[TraneWreck]

Howdy,

I have read these forums for a while and greatly appreciate the wisdom and expertise of the members. This is my first post here, and I would just like some answers to a couple of questions:

First, in a draft paper by NIST titled, Mechanical and Merallurgical Analysis of Structural Steel (I just learned I can't post links yet, sorry), NIST claims that their analysis of the paint cracking only established a maximum temperature of over 250C in a couple of places. I realize that NIST adds the caveat that the tested metal, both perimeter and core columns, was hardly representative.

My first question based on this paper is why NIST wasn't able to find samples that exhibited higher temperatures. I surmised that much of the paint, like the fireproofing, was blasted off where the temperatures were the highest, but this is hardly a scientific theory. Second, what was the process by which NIST estimated the heat of the fires. I read a loooooong paper from NIST about the fires in both buildings, but it was largely about where and how it traveled, I was unable to find their method of establishing the max temperature. The usual, stellar debunking sites (911myths, debunking911, etc) didn't have anything about that either.

The second main point I've been having trouble with is why, when calculating the heat, the maximum burning temperature of jet fuel, 980C, is relevant, whereas the open-air burning temp, 287.5C, is not. Basically, I don't understand what "open-air" means. I always assumed the heat in the WTC fires was largely a result of the bunches of crap (tables, desks, chairs, carpet...) that cought on fire that escalated the temperature, but I don't really understand the mechanism, nor was I able to find out much about it.

Anyway, sorry for the length and any answers or nudges in the right direction will be greatly appreciated.

[Quad4_72]

Not sure how you managed to post TWO threads. I am sure the mods will take care of it. Welcome to the forums.

[TraneWreck]

Thanks. I was trying to edit and ended up double posting. Nothing like announcing your presence with a deafening Cluster-F.

[T.A.M.]

I think the temperature question is of little value, as you have correctly pointed out, the contents of the buildings is certainly what kept the fires going, and what made them "soooo hot".

Welcome to the forum.

TAM:)

[Hokulele]

My first question based on this paper is why NIST wasn't able to find samples that exhibited higher temperatures. I surmised that much of the paint, like the fireproofing, was blasted off where the temperatures were the highest, but this is hardly a scientific theory.


Welcome to the forum, and I will just answer this little bit quickly. Since NIST was mostly concerned with making sure that the collapses were not due to poor design, construction materials, or construction methods, they needed samples of steel that could be identified and determined exactly where they came from. Any samples that were subject to extreme temperatures had all of their identifying markers destroyed, and were basically useless for NIST's purposes.

[gumboot]

I'm far from an expert on NIST, but I believe temperatures above 250 degrees destroyed the paint, thus preventing heat analysis of paint higher than those temperatures.

I think maximum threshold limits of air temperature were determined through a combination of full scale office fire tests and computer modelling.

I doubt the burning temperature of fuel played much of a factor in determining upper limits on air temperature. As you say, the primary source of heat was the burning material inside the buildings which was caught alight by the initial jet fuel fires. As any fire fighter can tell you, normal house and office fires can easily exceed 1000 degrees.

Here's a NIST video on the dangers of a dry Christmas Tree (as opposed to sitting a tree in a bucket of water to keep moisture in the leaves). What's worth noting is that flashover occurs after a mere 30 seconds. Flashover generally occurs with normal household contents at about 500 degrees.

[T.A.M.]

I think what he is getting at, is that of the samples NIST had, only two of them had the paint cracked, proving temps in excess of 250C. I am trying to recall if the rest of samples had their paint intact (indicating exposure to temps less than 250C) or whether many of them simply had the paint removed (from whatever process).

TAM:)

[TraneWreck]

Any samples that were subject to extreme temperatures had all of their identifying markers destroyed, and were basically useless for NIST's purposes.

Ahh, that makes a lot of sense. I know they talk about the difficulty in even establishing whether the paint damage on the samples the did study happened before or after the collapse.

Strangely cogent point from a Celtics fan...

[TraneWreck]

Hopefully a kindly administrator will clean up my mess and combine these threads.

[JimBenArm]

Ahh, that makes a lot of sense. I know they talk about the difficulty in even establishing whether the paint damage on the samples the did study happened before or after the collapse.

Strangely cogent point from a Celtics fan...
Better be nice to Hoke, 'cause she can hurt you. I have several scars to prove it.

[mrbaracuda]

Better be nice to Hoke, 'cause she can hurt you. I have several scars to prove it.

Hot.
Also: Hello TraneWreck.:jrefwelcome

[Hokulele]

Strangely cogent point from a Celtics fan...


Nyah. :p

Better be nice to Hoke, 'cause she can hurt you. I have several scars to prove it.


Hmph, those were just warning shots, nothing serious.

[Disbelief]

Thanks. I was trying to edit and ended up double posting. Nothing like announcing your presence with a deafening Cluster-F.

Then wouldn't TrainWreck be a more appropriate handle? :D

Welcome to the forum.

[OldTigerCub]

Howdy,

I have read these forums for a while and greatly appreciate the wisdom and expertise of the members. This is my first post here, and I would just like some answers to a couple of questions:

First, in a draft paper by NIST titled, Mechanical and Merallurgical Analysis of Structural Steel (I just learned I can't post links yet, sorry), NIST claims that their analysis of the paint cracking only established a maximum temperature of over 250C in a couple of places. I realize that NIST adds the caveat that the tested metal, both perimeter and core columns, was hardly representative.

My first question based on this paper is why NIST wasn't able to find samples that exhibited higher temperatures. I surmised that much of the paint, like the fireproofing, was blasted off where the temperatures were the highest, but this is hardly a scientific theory. Second, what was the process by which NIST estimated the heat of the fires. I read a loooooong paper from NIST about the fires in both buildings, but it was largely about where and how it traveled, I was unable to find their method of establishing the max temperature. The usual stellar debunking sites (911myths, debunking911, etc) didn't have anything about that either.

The second main point I've been having trouble finding information on is why, when calculating the heat, the maximum burning temperature of jet fuel, 980C, is relevant, whereas the open-air burning temp, 287.5C, is not. Basically, I don't understand what "open-air" means. I always assumed the heat in the WTC fires was largely a result of the bunches of crap (tables, desks, chairs, carpet...) that cought on fire that escalated the temperature, but I don't really understand the mechanism, nor was I able to find out much about it.

Anyway, sorry for the length and any answers or nudges in the right direction will be greatly appreciated.

I believe the "open air" vs. "maximum burning" teperatures were meant as a comparison between fuel that has been mixed with air by way of carburetion to achieve the most efficient burning as opposed to fuel that is just spilled out in a pool and set ablaze. The other combustibles in the WTC buildings were the wild card, and could have burned at signifcantly higher temps than jet fuel by itself.
(bolding mine)

Let me welcome you to the forum as well, TraneWreck!:)

[OldTigerCub]

Hopefully a kindly administrator will clean up my mess and combine these threads.

I dropped a note to the mods, so hopefully the threads will be merged.

[GreNME]

My first question based on this paper is why NIST wasn't able to find samples that exhibited higher temperatures. I surmised that much of the paint, like the fireproofing, was blasted off where the temperatures were the highest, but this is hardly a scientific theory.

Since NIST was mostly concerned with making sure that the collapses were not due to poor design, construction materials, or construction methods, they needed samples of steel that could be identified and determined exactly where they came from. Any samples that were subject to extreme temperatures had all of their identifying markers destroyed, and were basically useless for NIST's purposes.

Also, furthermore you need to consider that this isn't just a matter of testing materials after a fire. The fires began with a blast (removing some fireproofing) that literally tore things apart, which enabled the spreading of the fires very quickly (adding available surface area to fuel the flames from the blast). The best estimate for where the flames were hottest is going to be made in terms of general areas within the buildings-- which NIST did-- rather than specific square footage in the buildings. Even if fires hadn't occurred and the buildings still stood after that day, evaluating the extent of just the debris damage would have been an extensive project all on its own.

[ktesibios]

I think the best place to find the information you seek, TraneWreck, would be NIST NCSTAR 1-5, Reconstruction of the Fires in the World Trade Center Towers, and its sub-reports.

All of the final NCSTAR reports are available for free download here (http://wtc.nist.gov/reports_october05.htm).

The reports go into considerable detail about how NIST modeled the behavior of the fires and the likely temperatures they produced and how the results of the computer modeling were checked and validated by doing such things as comparing the predicted spread of the fires over time with what the photographic record showed of the locations of fire, and even by doing things like building representative cube-farm workstations, loading them with measuring instruments, setting them on fire and comparing the measurements with the predictions made by their CFD fire simulation software for an identical simulated cube farm.

BTW, if you dig through the reports until you find the pages that show the predicted temperatures of structural elements at different times, it turns out that the temperatures derived from paint analysis of the few recovered samples from core columns agree nicely with what the models predicted for those particular columns and locations.

[TraneWreck]

Then wouldn't TrainWreck be a more appropriate handle? :D
Welcome to the forum.

I used the handle on Branford Marsalis' old forum, and I kind of like it. The "Trane" is from John Coltrane. A bit of a pun, I suppose.

[TraneWreck]

BTW, if you dig through the reports until you find the pages that show the predicted temperatures of structural elements at different times, it turns out that the temperatures derived from paint analysis of the few recovered samples from core columns agree nicely with what the models predicted for those particular columns and locations.

Almost Eerie how those scientists manage to use multiple sources of information and paths of investigation, then watch as they convene on a single conclusion.

I'll check out the parts of NIST you suggest. There's so much to wade through, and Google is an imperfect tool for skimming.

Just a general thanks to every who responded, it's nice to have questions answered.

[TraneWreck]

I believe the "open air" vs. "maximum burning" teperatures were meant as a comparison between fuel that has been mixed with air by way of carburetion to achieve the most efficient burning as opposed to fuel that is just spilled out in a pool and set ablaze. The other combustibles in the WTC buildings were the wild card, and could have burned at signifcantly higher temps than jet fuel by itself.
(bolding mine)

At the risk of sounding dense, "open air" is the efficient temperature used in engine-driving combustion? I can't imagine the maximum temp would be very good for your airplane...

If that's the case, it seems like a very misleading term.

[BigAl]

As a data point, FDNY recently used an about-to-be-demolished residential apartment building for some experiments. They wired it up with sensors and set it alight.

http://video.google.com/videoplay?docid=-8682781475859149895&hl=en

The Fire chief cites 1700F temperatures measured.