Metatheory and the NIST report

[jay howard]

Don't forget the 3" rebar on 4' centers.

OK, this thread has officially jumped the shark. I'm out of here until somebody with enough sense to be worth it appears with a valid question.

And I'd still like to hear someone on the official side reconcile their dependency of the NIST report on simulations with NIST's own claims:



"NIST estimated the combustible fuel loading on these floors to have been about 4lb/sq ft (20 kg/sq m), 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."(NSCSTAR 1, 77)

"Simulations performed with doubled fuel loads slowed the fire spread well below the observed rates. Combined with the above results, this suggested that the estimated overall combustible load of 4 lb/sq ft was reasonable."(NCSTAR 1, 129)

This next one is particularly revealing:

"The principal combustibles on the fire floors were workstations. The total combustible fuel load on the WTC floors was about 4 lb/sq ft. Higher combusted fuel loadings resulted in slower fire spread rates that did not match the patterns observed in the photographic evidence. Under these higher combusted fuel loadings, the fires likely would not have reached the south side of the WTC 1 in the time needed to cause inward bowing and collapse initiation."(NCSTAR 1, 183)

The "middle" or "realistic" cases which NIST labeled A for WTC 1 and C for WTC 2 used this fuel load (4 lb/sq ft) estimate in the global analysis.

They also acknowledge that

"A number of preliminary simulations had been performed to gain insight into the factors having the most influence on the severity of the fires. The most influential was the mass of combustibles per unit of floor area (fuel load)..."(NCSTAR 1, 126)

Yet, when they used this "reasonable," "realistic," "middle case" in the simulations, they found that

"Upon preliminary examination of the middle cases, it became clear that the towers would likely remain standing."(NCSTAR 1, 144)

So NIST increased the fuel load, the most influential factor in the severity of the fires, despite the lack of rationale to do so, to 5 lb/sq ft.

In addition to this arbitrary fuel load increase and despite their warnings that the fire would not have spread to the south side of WTC 1 in time to initiate the collapse at these levels, NIST decided to use this estimate in the global analysis to support their theory.

Now, if anyone were to produce a simulation that demonstrated how the towers could not have fallen, and they used bunk information that was clearly not supported by estimates, would you not take issue with the validity of their argument-from-simulation? Of course you would. And you should.

Why then, when NIST arbitrarily increases the most influential factor in the severity of the fires by 25% to support their case do you accept it as good science? Why, if the difference between the two estimates is that the "realistic" one does NOT fail, and the exaggerated one DOES fail, do you accept the exaggerated results without a boatload of skepticism?

 

[rwguinn]

And I'd still like to hear someone on the official side reconcile their dependency of the NIST report on simulations with NIST's own claims:



"<<snip>>

Why then, when NIST arbitrarily increases the most influential factor in the severity of the fires by 25% to support their case do you accept it as good science? Why, if the difference between the two estimates is that the "realistic" one does NOT fail, and the exaggerated one DOES fail, do you accept the exaggerated results without a boatload of skepticism?

Ever stop to think that an airplane full of JET-A might contribute a bit to the situation.
Note that they said ""Simulations performed with doubled fuel loads slowed the fire spreadwell below the observed rates. Combined with the above results, this suggested that the estimated overall combustible load of 4 lb/sq ft was reasonable."(NCSTAR 1, 129)"
Normal fire simulations use a spread from a source location (Someone with credentials correct me if I'm wrong). The JET-A would have spread the fire a lot more quickly--requiring an increase in fuel load in the sim to match observations.

The most important thing is that the sim must match reality. The other way around never works.
So, with that demo of reading incomprehension on the part of a twooist, I am done here.

 

[jay howard]

Ever stop to think that an airplane full of JET-A might contribute a bit to the situation.
Note that they said ""Simulations performed with doubled fuel loads slowed the fire spreadwell below the observed rates. Combined with the above results, this suggested that the estimated overall combustible load of 4 lb/sq ft was reasonable."(NCSTAR 1, 129)"
Normal fire simulations use a spread from a source location (Someone with credentials correct me if I'm wrong). The JET-A would have spread the fire a lot more quickly--requiring an increase in fuel load in the sim to match observations.

The most important thing is that the sim must match reality. The other way around never works.
So, with that demo of reading incomprehension on the part of a twooist, I am done here.

So, how have you answered the question? How does NIST justify the increase in the fuel load by 25%--or more to the point, given the fact that they make no attempt to justify this increase, why do you still stand behind their theory?

If you cannot give a reasoned explanation, you are simply maintaining an article of faith. You are guilty of exactly the type of soft-headed acceptance that you accuse the "twoofers" of.

So please, present an argument--not just some righteous indignation at my citing of the NIST report--or remain silent.

 

[twinstead]

if you cannot give a reasoned explanation, you are simply maintaining an article of faith. You are guilty of exactly the type of soft-headed acceptance that you accuse the "twoofers" of.

So, what you are saying is at the very least, we are guilty of the type of soft-headed acceptance that we accuse YOU of, right? Well, YOU are guilty of the type of soft-headed accepance that you accuse US of.

I submit that in you are half right. What YOU have is soft-headed acceptance. You totally blew rwguinn's post off with a flurry of crap, and had the nerve to ask for an argument when faced with a bold-faced argument.

 

[R.Mackey]

Ever stop to think that an airplane full of JET-A might contribute a bit to the situation.
Note that they said ""Simulations performed with doubled fuel loads slowed the fire spreadwell below the observed rates. Combined with the above results, this suggested that the estimated overall combustible load of 4 lb/sq ft was reasonable."(NCSTAR 1, 129)"
Normal fire simulations use a spread from a source location (Someone with credentials correct me if I'm wrong). The JET-A would have spread the fire a lot more quickly--requiring an increase in fuel load in the sim to match observations.

The most important thing is that the sim must match reality. The other way around never works.
So, with that demo of reading incomprehension on the part of a twooist, I am done here.

Actually, it's simpler than that.

The quote that "the Towers would likely remain standing" is based on the preliminary models -- and also doesn't mean "likely to remain standing forever." It actually means that, under those cases, the Towers would still have collapsed, but it would have taken longer than it did in reality.

As it turns out, the fuel loading is actually not that relevant. More relevant is the fuel placement, and how the fuel load determines the location -- not the intensity -- of the fires.

An increase in fuel load from 4 lb/ft² to 5, i.e. 25%, is small compared to the increase that was tested during model sensitivity testing. That sensitivity testing, in which the fuel load was increased by 33%, found that the fuel load was relevant but only with respect to the duration of fires. See NCSTAR1-5F section 5.2 for the sensitivity analysis.

The overall effect of fuel load on the fires is described in Chapter 6 of NCSTAR1-5F:

The results of the Case B simulation of WTC 1 are included on the following pages (Figs. 6-18 through 6-25). In general, the results were similar to Case A because the fires in WTC 1 were limited by the supply of air from the exterior windows. As the window breakage pattern was not changed in Case B, the extra combustibles within the building did not contribute to a larger fire, but they did delay the spread slightly because the fires were sustained longer in any given location due to the increase in combustible load.

In Case C and D, of course, there was no change in the combustible load at all:

Unlike WTC 1, the designated combustible load in WTC 2 had a noticeable effect on the outcome of the simulation. Because most of the windows on the impact floors were broken out by the airplane debris and the ensuing fireball, there was an adequate suply of air for the fires. In the Case D simulation of WTC 2, the combustible load was kept at 20 kg/m², the same as case C, but the aircraft debris and "rubble" were spread out over a wider area. In Case C, the debris pile was concentrated in the northeast corner of the 80th, 81st, and 82nd floors, whereas in Case D the pile was less concentrated. Also, in Case D, the furnishings away from the impact areas were assumed to be undamaged.

Therefore, the complaint about increasing the fuel load in WTC 1 is groundless, and stems from lack of comprehension about the report.

It is similarly incorrect to state that the fuel loading or placement defined Cases A and C versus B and D. More importantly, B and D involved more impact damage, especially fireproofing damage. That makes a far greater difference than any change in the fuel load.

The reasons to prefer the higher impact damage estimates are given in NCSTAR1-2B. We've discussed them to death in this thread (skipping most of the crap in that thread), and besides that cases B and D were seen to better simulate the leaning and floor behavior than cases A and C. This is why A and C were rejected:

WTC 1 and WTC 2 global models were subjected to Case B and Case D aircraft damage and fires, respectively. The results of the isolated wall, core, and full floor analyses indicated that structural responses to Case B and Case D more closely matched observed structural behavior in photographs and videos than did Case A or Case C respectively.

For more information about this, please see Chapter 7 of NCSTAR1-6.

 

[e^n]

No, I believe the bowing occurred but only after the central core columns collapsed first.

I do not know that the times are correct on the photos and believe the stills could have been taken from video just as the collapse initiated. The photos are not the best evidence for perimeter column bowing occurring for minutes prior to collapse. The videos do exist so why aren't they used or released so we can compare the photos to them?

I gave you the website address of one of the people who took the photos used by NIST who is actually selling photos on his website which show the bowing!

Have you still not contacted this person or reviewed the images available freely on his website?

 

[Tony Szamboti]

I gave you the website address of one of the people who took the photos used by NIST who is actually selling photos on his website which show the bowing!

Have you still not contacted this person or reviewed the images available freely on his website?

I did review the images on his website. These photos do not prove that the perimeter columns were bowing minutes before the collapses. Where are videos showing the perimeter columns bowing for minutes before the collapses?

If NIST would release the videos they have, that some stills were possibly taken from, maybe we could see if there was bowing occurring for minutes before the collapses. As for the videos available on the web I do not see bowing minutes before the collapses.

 

[Gravy]

I did review the images on his website. These photos do not prove that the perimeter columns were bowing minutes before the collapses. Where are videos showing the perimeter columns bowing for minutes before the collapses?

Fourth time: What happened to your FOIA request for the video? Was it denied? If so, what reasons were given?

 

[e^n]

I did review the images on his website. These photos do not prove that the perimeter columns were bowing minutes before the collapses. Where are videos showing the perimeter columns bowing for minutes before the collapses?

Why must it be a video? You can clearly see from the photographs he makes available that unless he was using a portable HDTV camera they are not from a video. These are the images NIST uses to support the bowing theory most likely because he had a good reference point for times thanks to EXIF information.

You can contact him yourself and indeed you claimed you were going to do so to ask him at what times he took said pictures. Why have you neglected to do so yet continued to claim that the evidence isn't there?

Just for kicks I did a quick review of the footage available, I cannot find any video of high enough quality or zoomed in enough to isolate bowing, although minor movement is available on NBC's coverage beginning at 13s before collapse (quick guesstimate, I haven't checked thoroughly)

 

[GlennB]

Why must it be a video? .....

Because he already knows that it doesn't exist or would be very difficult to obtain. By insisting on evidence that sceptics cannot produce at will, he creates his own security-blanket. With this he is impregnable, but in a rather sad way.

If there were such a video, he'd be asking for something else.

 

[Gravy]

Because he already knows that it doesn't exist or would be very difficult to obtain. By insisting on evidence that sceptics cannot produce at will, he creates his own security-blanket. With this he is impregnable, but in a rather sad way.

If there were such a video, he'd be asking for something else.

It does exist, and its source is printed on the still photos in the NIST report. That's why I'm asking Mr. Szamboti what has become of his attempts to get a copy.

 

[T.A.M.]

Requesting real evidence, will only put in the public domain evidence to destroy their theories...why would they do that??

TAM

 

[GlennB]

It does exist, and its source is printed on the still photos in the NIST report. That's why I'm asking Mr. Szamboti what has become of his attempts to get a copy.

Indeed. And he won't try to obtain it, he'll expect sceptics to do the work and then - if they do - he'll claim that some agency has been sitting on it for so long they've had time to fiddle it. He doesn't want evidence, he's looking for any excuse to go on believing.

 

[Gravy]

Indeed. And he won't try to obtain it, he'll expect sceptics to do the work and then - if they do - he'll claim that some agency has been sitting on it for so long they've had time to fiddle it. He doesn't want evidence, he's looking for any excuse to go on believing.

Exactly. I just like to call the bluff of these frauds. This is the third time I've done so with realcddeal. He couldn't defend his own paper, and he didn't step up to the plate after my challenge to him in his first thread:

realcd, whom have you contacted with your question? Gene Corley? Abolhassan Astaneh-Asl? Have you contacted ANY of the people who made the decisions that you're asking us – who had no say in the matter – about?

If not, why, and will you do so?

Gravy, you are right I should go ask the question of those who might actually have the answer.

I'm sure we'll be interested in what responses (if any) you get. The NIST and FEMA reports list the investigation leaders and their places of employment (as of 2005, in NIST's case). I know that many of them can be contacted at the listed companies.

Let us know what you hear. It's an interesting question that I believe is addressed in the NIST report, but perhaps you can glean more details.

Okay, realCD, you've made your beliefs clear.

Now what are you going to do about them? This seems to be a pressing issue for you. Will you contact the people who made the decisions? Will you start that process right now?

Your opinion is noted, as it was after your first post.

I'll echo kookbreaker's comment: NOTHING is going to "shut down" conspiracy theories, especially a government investigation, because these theories are made out of whole cloth. Nor is it the government's job to cater to the whims of conspiracy theorists.

However, there are facts aplenty that refute these theories with no further investigation needed. You just have to be a rational person who values truth over fantasy. In my signature you'll find a ink to many resources for accurate information about 9/11 issues.

I take it you're not going to contact the engineers involved, then?

I would very much like to ask questions of the volunteer ASCE members like Gene Corley. You were right that that is where I should go for answers.

I ask you yet again: will you start that process now? Yes or no?

I can't figure out why you're still opining on this subject. You made your opinion clear in your first post.

Do you have any evidence – anything at all – of dishonesty by the 9/11 investigators that could have affected the outcomes of the many investigations?

Fourth time, realcd: are you going to contact the people who can answer your question? You have twice agreed that you should do so.

Will you begin that process now? Yes or no?

Unfortunately, there is no physical evidence for the fire weakening theory and it just isn't solid enough to convince the public. There needs to be another investigation of what went on at the Twin Towers.

It isn't conspiracy theory to say the case just simply hasn't been made and go back and do it again. This happens all the time in law enforcement. The conspiracy theories start when there is stonewalling and an attempt to truss up a weak theory.

If there's all this non-investigating going on, why did NIST reject FEMA's pancaking theory, and why is WTC 7 still under investigation? These criminal engineers could have finished that report years ago, right?

And please answer my other questions. They aren't going away.

As far as contacting people who were involved in the investigation I said I will and I mean that.

You are simply expressing your opinion here. Sorry to be blunt, but I don't think that anyone here cares about your opinon. While you're attempting to debate people who weren't involved in the FEMA and NIST investigations, you could be having your questions answered by those who were involved. So get on with it. You've got work to do.

Why don't you name more than a handful of these experts you speak of there Dave and don't forget to show where they agree with it in writing?

Dude, I thought you said you were going to contact these experts. Now you say you don't even know who they are?

On this page you'll find 145 structural and fire protection engineers who worked on the investigations. The list doesn't include most of the engineers who've written scholarly papers on the subjects.

Let's see the list of qualified engineers who support your claims. Fair enough?

After that he went into full-blown troofer mode and accused us of being paid government operatives.

Conclusion: any conspiracy theory can be perpetuated simply by whining on the internet.

 

[jay howard]

The quote that "the Towers would likely remain standing" is based on the preliminary models -- and also doesn't mean "likely to remain standing forever." It actually means that, under those cases, the Towers would still have collapsed, but it would have taken longer than it did in reality.

It’s not relevant to the discussion that the towers would eventually fall. The task was to demonstrate how they could possibly have fallen in the well-defined time constraints.

More to the point, how is it you know that what NIST “actually mean” when they say “the towers would likely remain standing” is that “the Towers still would have collapsed”? You would think if they wanted to express that, they would have said that. But they don’t. They say “the towers would likely remain standing” without an indication to the contrary. This is apparently one of the reasons they did not appeal to the middle cases for their global analysis.

In order for your position to make sense, you must take not just an alternate meaning from their words, but the opposite meaning. This post could be shortened a large amount by just saying “no it didn’t”. That’s the crux of your position. Do you consider that an acceptable argument when the opposing camp responds to you? I doubt it.

As it turns out, the fuel loading is actually not that relevant. More relevant is the fuel placement, and how the fuel load determines the location -- not the intensity -- of the fires.

So what did they mean when they said the most influential factor in the severity of the fires was fuel load? Were they mistaking their own words? Did they misunderstand themselves? How is it you know what they mean better than they do? How are you more of an authority on the NIST report than the NIST report is?

How do you go from “most influential factor” to “not that relevant”?

An increase in fuel load from 4 lb/ft2 to 5, i.e. 25%, is small compared to the increase that was tested during model sensitivity testing.

And was the purpose of the sensitivity testing to determine the office fuel load? Clearly it was not. The sensitivity testing was to determine which factors would have the greatest effect on the simulations. Increasing the fuel load was meant to figure out how accurate they needed to be in their estimation of the fuel load. If it wasn’t that big of a factor, they wouldn’t need to be that accurate. As it turns out, (unless it’s opposite day), fuel load is the most important factor in the simulations, at least according to NIST. So, it is very important that the fuel load estimates match as closely as possible in order to produce a meaningful simulation.

That sensitivity testing, in which the fuel load was increased by 33%, found that the fuel load was relevant but only with respect to the duration of fires. See NCSTAR1-5F section 5.2 for the sensitivity analysis.

Right. The duration of the fires was increased with the increase of the fuel load. This is common sense. More fuel in an equally ventilated area will not increase the temperature, just the amount of time the fire burns. No big surprise here. This increased duration, by NIST’s estimates however, is the key factor in producing sagging trusses.

In Case C and D, of course, there was no change in the combustible load at all:

Unlike WTC 1, the designated combustible load in WTC 2 had a noticeable effect on the outcome of the simulation. Because most of the windows on the impact floors were broken out by the airplane debris and the ensuing fireball, there was an adequate suply of air for the fires. In the Case D simulation of WTC 2, the combustible load was kept at 20 kg/m2, the same as case C, but the aircraft debris and "rubble" were spread out over a wider area. In Case C, the debris pile was concentrated in the northeast corner of the 80th, 81st, and 82nd floors, whereas in Case D the pile was less concentrated. Also, in Case D, the furnishings away from the impact areas were assumed to be undamaged.

Therefore, the complaint about increasing the fuel load in WTC 1 is groundless, and stems from lack of comprehension about the report.

You mean WTC 2. They did in fact, increase the fuel load from 4 lb/sq ft to 5 lb/sq ft in Cases A to B respectively. You are right that in NCSTAR 1-5F, they do not change the fuel load between cases C and D. Strangely, in the final report, the table on page 126 (Table 6-6) clearly indicates the fuel load difference between cases C and D as 4 lb/sq ft and 5 lb/sq ft respectively. But since 1-5F is the more detailed study, we should examine it more closely.

What they say in regard to the alignment between observable events and event simulation is that case C is a better fit. In their words, in regard to floor 81 of WTC 2:

To simulate the intense fires in the northeast corner (Fig. 6-33), a heavy concentration of combustibles was prescribed there under the assumption that the upper fuselage and right wing of the airplane plowed an appreciable amount of the combustible load of the east side of the floor into that corner. As expected, the predicted temperatures were highest in the northeast, with some fire activity predicted in the southwest (where none was observed) and some in the north central (where a light amount was observed). Page 94

The heavy concentration of combustibles in the corner produced a fire that lasted an entire hour in that location, consistent with visual evidence. Page 87

This is in contrast to case D:

In Case D, the furnishings were restored to their “undamaged” state, except in the immediate vicinity of the airplane impact, to create a more severe fire. Page 87

In Case C, the debris pile was concentrated in the northeast corner of the 80th, 81st, and 82nd floor, whereas in Case D, the pile was less concentrated. Also, in Case D the furnishings away from the impact areas were assumed to be undamaged. Page 100

So, again, the NIST reporters must go against their own analysis (that the plane would likely have plowed a pile of debris into the northeast corner of WTC 2—consistent with the visual evidence as they fully admit) in favor of a less empirical data set which just happens to produce a “more severe fire.”

Am I making this up? Check for yourself.

 

[TellyKNeasuss]

Take a look at an avalanche and you won't see a lot of dust in the air until it is further downslope. The towers released tremendous dust clouds immediately

One difference is that most avalanches aren't on fire.

 

[TellyKNeasuss]

Why must it be a video?

Because if it can't be shown on YouTube, it isn't valid evidence.

 

[TellyKNeasuss]

The towers released tremendous dust clouds immediately and while the mass was high it was initially a slow fall which does not produce heavy dust from solid objects. High velocity impacts are normally needed to generate heavy pulverization and dust.

Really? Please explain why this must be so.

 

[Tony Szamboti]

Really? Please explain why this must be so.

High velocity shock is required to pulverize.

Velocity shock = 2 x height of the fall/deflection

In the cases of both towers the deflection was very high and essentially equaled the fall providing no more than a 2G hit.

 

[cmcaulif]

High velocity shock is required to pulverize.

Velocity shock = 2 x height of the fall/deflection

In the cases of both towers the deflection was very high and essentially equaled the fall providing no more than a 2G hit.

You realize that a great deal of that dust cloud was gypsum wallboard, ceiling tile, and other man made vitreous fiber right?

A child can pulverize that stuff with a toy hammer.

And I suppose you have seen the latest from Bazant, Le, Benson, and Greening? In order to achieve the same degree of concrete pulverization with explosives, the charges would need to be wired into small holes drilled into the concrete floor slabs on every single floor. Tell me why no one noticed the ripped up carpet, or the crews working, or the moved cubicles while this massive project was underway.