OK, thanks. I'm going to assume that this discussion doesn't change much in the final report, for now. I have them both, but comparing takes time. So it seems that what we have here is a statement that air temperatures in the upper layers of the tenant spaces above regions of active fire reached 1000 C at least for some period of time. It's clear from statements made in the paragraphs right above the one you quoted that the regions of active fire were continuously moving through the tenant spaces. It seems from the description and the figure right above this paragraph that the events described were supposedly happening roughly between 9:38 a.m. and 9:58 a.m. In addition, we have the statement that hot gases from the fire floors were able to move into the core from the tenant spaces on floors 94-97, where gypsum walls had been broken by the impacts, so that similar temperatures to those in the tenant spaces could have been reached in the upper levels of the core air. It's certainly not clear that this means 1000 C gases entered the upper air levels of the core or whether it is mostly gases at the more generally prevailing 500 C temperatures of the upper level air in the tenant spaces. It isn't actually explicitly stated in the lines you've quoted exactly what air temperature was reached in the upper levels of the core, or for how long, at least not here. It doesn't follow that the steel of the core columns would have reached equally high temperatures throughout the whole of the columns, even if the thermal cladding were completely stripped and the steel were fully exposed. It would take some time before that could occur, and indeed, the next paragraph of the description makes this clear enough: The image didn't come through in the forum, apparently, but it did come through when I quoted your post to reply, so luckily I was able to see it, and figure out what it actually is supposed to represent. It's a 2-d graphic depicting the results of one of the fire simulations that I was referring to before. This particular graphic is found on page 127 of the final report, where it is figure 6-36. It is also in the draft report, although there it is printed at an angle, and is part of figure 6-37 which appears on page 126. The caption of figure 6-36 in the final report reads: So this is a graphic of upper level air temperature on the 94th floor, as opposed to upper level air temperature in the upper levels of the core near the 97th floor. Also, impact was at 8:46:30 a.m. So fifteen minutes after impact would have been 9:01:30. Therefore this graphic depicts a very different thing, than the temperature in the upper air of the core near level 97, some 40 minutes to 1 hour later on, at 9:38-9:58 am. So there's no contradiction, as far as I can see. I can't find this quote either on p98 or on p148. Are you sure you have the right page number? As I said, I can't seem to find that quote right now. But I certainly believe that the quote is there somewhere. I think that, likely, the experiment was done because the simulations clearly did suggest that such temperatures were actually reached in the floor slabs as opposed to the core. See, for example Figure 2-11 on page 31 of the final report, which represents the temperatures on the top and bottom surfaces of the 96th floor slab at a time of 100 minutes after impact, and consider also the quite high temperatures reported above active fires in the upper level air of the tenant spaces. This refers to samples of structural steel that were analysed, and to me it suggests also that some samples were found that reached temperatures as high as 600 C. Of course, it was made clear in the report that the temperature that various pieces of steel reached depended on what type of member was being considered, how much insulation it had, and for what duration it was exposed to high temperature. So this certainly doesn't prove that the temperatures in the simulations couldn't have been reached. No, I don't agree that it gives that impression. I don't think that the section you quoted clearly says how high the temperature was or for how long it was that high. I agree that the language of the quote could be more explicit about the temperatures. But it would only be deceptive to say what is said there if the simulations never did reach high temperatures in upper level air of the core near floor 97. If you look at figure 6-37 on page 128 of the final report, you can see that it appears that there were, at some times in the simulations, temperatures near 1000 C in the upper level air of the core, on the 97th floor. Cheers!
This quote describes the results of an actual experiment using materials and geometry similar to what was burning in the floor spaces of the WTC, which was done in order to test how well the fire simulation code (FDS) was able to simulate. Here, I'll add back in some of the important context for the quote, that you've omitted, so that it will be clearer what it is about: Much clearer, no?
Apologies rb88, didn't check previous pages on forum before posting. Nonetheless, the video raises some interesting questions. Of all the 4 flights, this 1 is the most puzzling.
i am sorry but what they say is pretty clear and if is not to u, it is one more reason to assert it is deceptive. they compare upper layers and upper layers near the fire in the tenants areas to the cores area and they state that temperatures were similar: by saying 'similar temps' u can conclude that they didnt differ enough to grant a specification. i think u either forgot or missed that they mention that temps ranging from 500-C to 1000-C were thought to be on the97th and in the 94th floor upper layers, it's even in your quote. not sure i completely follow here but it doesnt make any difference since they same temps apply to both 94th and 97th floor as they write and as u quoted above, and the graphic is clearly of the 94th floor. also it is pretty clear temps were never above 300-C, yet they state it is at least a persistent 500-C. well, that's not the case in the sim. well, it is obviously there. from whatever angle u wanna look at it. have to go trough the report once again, i have no time now. u see that's where i think both u and the nist are wrong here; first, no sample whatsoever ever reached temps above 600-C, that was made sufficiently clear. not only that but most of the steel analyzed cleary suffered temps of around 300-C. and u just cant explain what happened with the results of a simulation if the same results contradict the evidence. remember that the sim data was used to explain failure and consequent collapse. this is clearly unscientific. i am talking about the 94th floor and those temps there sure weren't in the core, but in the borders of the core. it is obvious to me that the whole temps analysis is not clear at best and borderline deceptive at worse. thx for your reply.
If something is unclear to me, it certainly doesn't mean that it's necessarily deceptive. There's another possibility than that it is deceptive, there are actually at least three: you misunderstand what is written, I misunderstand what is written, or both of us do. There's more than one temperature attributed to the upper air layer in the tenant spaces. 1000 C above active fires, 500 C more generally. Active fires are moving all around and hotspots of 1000 C move above them. 500 C temperatures are much more widespread on the graphics of fire temperatures on fire floors. No I didn't forget that. It's in the quote with regard to the temperatures in the tenant spaces. The upper layer air in the core is a different matter, I think. My understanding is: once hot gases move from the tenant spaces through gaps in the gypsum walls surrounding the core column structures on any of levels 94-97, they are then free to begin moving upwards within the core. They don't necessarily remain on the level at which they entered the core. They can move upwards until they are blocked by some horizontal partition. You posted a graphic of the temperatures on the 94th floor 15 minutes after impact and concluded from that, that temperatures in the core never reached above 300 C. That's a mistake. It's very easy to see: look at the graphic for the 97th floor, as opposed to the graphic for the 94th. You will see that at impact + 15 minutes, temperatures in the core region of the 97th floor were at 1000C in some spots, as opposed to the 94th, where they were far lower in the core region. I simply don't understand your reasoning as to how this evidence contradicts the results of the simulation of the air temperatures. What is it that you think should have been found in the temperature history analysis of the steel samples in order for thermal failure to have been a possibility? But on the 97th, those temperatures were there in the core, at least for some time in the simulation. And obviously, we only have a few frames to look at, not the full time history of the temperature profile. You drew an extremely strong conclusion. You said that temperatures never reached above 300 C in the core, in the simulations, based on a picture of the 94th floor at one instant: 15 minutes after impact. I think one should be very reluctant to say that something is deceptive given that one thinks it is unclear. In my opinion, it would be a good thing for NIST to make the full time histories of the simulations available. That would allow them to be analysed. Cheers!
yeah agreed with that. but i find it odd that they would not make clear a passage of such relevance. yes, that's correct. no i dont agree it is a different matter for what regards the cores. and yours is just an interpretation of what is written. it is not clear at all and open to debate if gases were free to move upward within the core, nothing in the nist quote seems to suggest that. anyways, let me clarify what i meant in my previous posts and let's go trough the nist first report once again: "aside from isolated areas, perhaps protected by surviving gypsum walls, the cooler parts of this upper layers were at about 500-C, and in the vicinity of the active fires, the upper layer air temperatures reached 1000-C. the aircraft fragments had broken trough the core walls on the 94th trough the 97th floors, and temperatures in the upper layers there were similar to those in the tenant spaces". as u can see in the bold lines nist doesn't distinguish which floors did sustain those temperatures and refers to both when comparing the temps in the core to those of the tenant spaces. and nist is obviously indicating here both tenants and core areas share the same temperaures, because, and u seem to disagree, the nist makes no clear distinction between the temps in the tenants areas upper layers and the core upper layers. yeah but as i stated in the quote above there ain't no distinction between 94th and 97th, infact it seems obvious to me they are referring to the 94th floor and the 97th. and attributing higher temps to another entire floor makes a huge difference. of course it contradicts the results: the map i posted shows the areas of the cores of the 94th floor in blue indicating that temps there were below 300-C. i can't see any reason to state that temps reached at some point 500-1000-C on both floors, there's just no graph of the 94th floor indicating that ...only the 97th, u say shows that. if nist didnt mention the 94th floor in the p28/78 quote it would be a totally different matter but the 94th is there and the temps were attributed to it as well. that seems inescapable to me. much higher and persistent temperatures. well, first, it is pure speculation that other diagrams of the temps were made and i cant see any good reason why they weren't included in the report since they would be extremely relevant. also, i didn't see and have yet to see the 97th floor diagram so i might have been wrong saying core temps were definitely below 300-C, but the diagram of the 94th floor indicates temps were not as high as stated. i cant see any logical reason to believe based on the evidence that 500-1000-C were reached also in the 94th and i think i made that clear already and was infact correct to say that. so, it appears to me like an effort to make it look as if high temps were infact more widespread then they truly were: implying that another floor was also subject to high temps makes an enormous difference since it should be just 1 floor alone; it is like pumping the evidence by a full +100%. that aside, i think nist itself drew strong conclusions since it was only a simulation and there's no photographic evidence to back it. infact, temps of and above 1000-C are usually observed for a short period of time in building fires and the phenomenon is known as 'flashover' and typically last for seconds not minutes. and we have to remember how wrong nist sims were, after they backed the pancake theory with a simulation as well and then were forced to drop it. yes and we can keep arguing forever here without going anyhere. what's evident is that we need a new investigation, there's not a shred of doubt about that. thx and have a good 1.
dpt, i'd like to discuss wtc7 and eventually wtc5-6 with u going forward. i think the colllapse of wtc7 is very telling and the least analyzed. cheers
Is there an 'official' reason as to why building 7 collapsed? I read somewhere that the official investigation into the collapse of the building has not been released yet and is due for early 2007, but cannot say if the source is reliable or not.
official version: "probably due to fire but in reality it is extremely unlikely so we don't have a clue".
all explanations for anything they put out so far come with the disclaimer 'has a low probability".... yet these fools just eat it up.