WTC7: Did the fires burn long and hot enough?

[Oxymoron]

Did you read the NCSTAR 1-9 analysis of the location and extent of the fires? Did you find anything wrong with it?

Yes to both. I posted here https://www.metabunk.org/posts/41014

The fires are not sufficiently hot or long enough to cause the collapse... let alone a 'uniform, straight down, collapse'... What are the chances of that happening BTW... Any statatitions like to come up with an odds for random office fires in a massive building causing a uniform collapse similar to a demolition.

http://911research.wtc7.net/letters/nist/W...ents_JCole.html

Content from external source:

"Paragraph/Sentence: Section 3.4.5 Second to last paragraph. "Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel temperatures that were approximately 400º C or less, primarily due to the effects of thermal expansion. After 4 h of heating, there was substantially more damage and failures in the WTC 7 structural system than at 3.5 h of heating." And in the next paragraph: "However, it appeared likely the critical damage state occurred between 3.5 h and 4 h."

(Cole) comment: Exact input details of the NIST model were not provided for review. However, based on the above, it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C., or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.

Reason for Comment: Based on Figure 3.6, Page 30 (NCSTAR 1A) temperatures near the floor system of Column 79 did not sustain temperatures of 400º C for a time in excess of 3.5 hours. Rather, this indicated a time of perhaps 2 hours.

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."

Finally, Floors 12 and 13 (the SEC floors) were determined to be the hottest, yet: "Fire was first observed on the 12th floor, on the south side of the east face, at about 2:10 p.m." (Page 381 NCSTAR 1-9 Vol 2), and didn't even begin to heat up the areas near Column 79 until around 3:00 p.m.
NCSTAR 1-9 Page 243 for the 8th floor: "As late as 3:22 p.m., there was no indication of fire in this area but about 17 min later a substantial fire spreading to the east was visible between windows 8-47C and 8-53C."
NCSTAR 1-9 Pages 244 and 245 state: 11th floor: "A fire was first observed at 2:08 p.m. on the east face.", and for the 12th floor, a similar time.

For the 13th floor: "The first visual evidence for burning on the 13th floor was seen on the east face around 2:30 p.m."; less then 3 hours before the collapse.

And even more importantly, the floor temperatures predicted (Figure 3-8 Page 31 NCSTA 1A) indicate temperatures colder then 200º C as late as 4:00 p.m. in the area of Column 79, and not until about 5:00 p.m. (20 minutes before collapse) does only a small portion of the floor area theoretically approach temperatures of 400 C. But the building collapsed at about 5:21 p.m. in the afternoon, about a half hour later, far less time than the critical 3.5 hour time used in the model.

If the entire analysis of the initial failure event is dependent on temperatures approaching 400º C that must exist over 3.5 hour period, and/or the fires did not last that long in the critical Column 79 area, then the entire foundation of the simulation appears flawed. And if the input of the model is flawed, the output results and conclusions are also flawed.

 

[Mick West]

So this looks like bunk to me, they claim that NIST says it would take 4 hours at 400C to cause the damage, and yet no region was at 400C for more than 30 minutes?

If this is correct then obviously the NIST conclusion must be incorrect. Now I doubt that such an error could have gone unnoticed, so my initial supposition is that it's actually bunk.

Oxy, did you go and verify these claims?

 

[George B]

So this looks like bunk to me, they claim that NIST says it would take 4 hours at 400C to cause the damage, and yet no region was at 400C for more than 30 minutes?

If this is correct then obviously the NIST conclusion must be incorrect. Now I doubt that such an error could have gone unnoticed, so my initial supposition is that it's actually bunk.

Oxy, did you go and verify these claims?

This is in the NIST Report I posted it earlier myself on this Thread . . .

 

[Mick West]

This is a good place to start:

911Research:

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."

The actual NIST NCSTAR 1-9 section 8.4.1:
https://www.metabunk.org/files/NCSTAR_1-9_WTC7_unlocked.pdf

Prediction of growth and spread of building contents fires (Section 9.3.2) indicated that such
fires moved from one location to the next (e.g., from one office cubicle to the next) and burned intensely
in any one location for roughly 20 min to 30 min. However, the large floor area surrounding Column 79
would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

Now why would 911Research leave that bit off?

I suspect looking into the full context of all their other quotes will reveal more bunk.

 

[George B]

This is a good place to start:

911Research:

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."

NIST:
https://www.metabunk.org/files/NCSTAR_1-9_WTC7_unlocked.pdf

Prediction of growth and spread of building contents fires (Section 9.3.2) indicated that such
fires moved from one location to the next (e.g., from one office cubicle to the next) and burned intensely
in any one location for roughly 20 min to 30 min. However, the large floor area surrounding Column 79
would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

Now why would 911Research leave that bit off?

I suspect looking into the full context of all their other quotes will reveal more bunk.

So in serial manner the fires would burn a cubical at a time . . . this does not equate to the temperature on the floor being uniform or maintaining itself at the maximum level over the entire floor for two to three hours . . .

 

[Mick West]

So in serial manner the fires would burn a cubical at a time . . . this does not equate to the temperature on the floor being uniform or maintaining itself at the maximum level over the entire floor for two to three hours . . .

Arguable, however that's not exactly the point. The point here is that the original claim was bunk. They quote a bit of NIST seems to support their case, but leave off a bit that directly contradicts it. Does this make it a good case?

What of the other claims there? Does NIST actually say it takes four hours for fire, but they only account for three? Is that accurate? Did you check?

 

[Oxymoron]

This is a good place to start:

911Research:

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."

NIST:
https://www.metabunk.org/files/NCSTAR_1-9_WTC7_unlocked.pdf

Prediction of growth and spread of building contents fires (Section 9.3.2) indicated that such
fires moved from one location to the next (e.g., from one office cubicle to the next) and burned intensely
in any one location for roughly 20 min to 30 min. However, the large floor area surrounding Column 79
would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

Now why would 911Research leave that bit off?

I suspect looking into the full context of all their other quotes will reveal more bunk.

Perhaps they left it out because it seems irrelevant, contradictory and bunk in itself... as George says "So in serial manner the fires would burn a cubical at a time . . . this does not equate to the temperature on the floor being uniform or maintaining itself at the maximum level over the entire floor for two to three hours . . ."

Of all the columns, NIST put in a non confirmable caveat on column 79?.

It is logical and can be visually confirmed that fires were generally present in a few windows at a time with burned out sections clearly visible as the office fires moved on.

NIST is using made up figures and estimates to arrive at a preconceived outcome and they are finding it difficult.

 

[George B]

Arguable, however that's not exactly the point. The point here is that the original claim was bunk. They quote a bit of NIST seems to support their case, but leave off a bit that directly contradicts it. Does this make it a good case?

What of the other claims there? Does NIST actually say it takes four hours for fire, but they only account for three? Is that accurate? Did you check?

I am not sure of what you are asking . . . cherry picking (bad) and selecting small enough quotes to make a point without overwhelming the Thread (good) are often conflicting desires . . . when I first reviewed the report I was not aware there was a simulation portion of the Report . . . my bad . . . at this time . . . are you saying NIST says the temperatures could have been uniform, hot enough and long enough to cause collapse initiated by column 79 and the selected quotes were chosen to deny that?

 

[Mick West]

I am not sure of what you are asking . . . cherry picking (bad) and selecting small enough quotes to make a point without overwhelming the Thread (good) are often conflicting desires . . . when I first reviewed the report I was not aware there was a simulation portion of the Report . . . my bad . . . at this time . . . are you saying NIST says the temperatures could have been uniform, hot enough and long enough to cause collapse initiated by column 79 and the selected quotes were chosen to deny that?

I am asking how accurate is the analysis in Oxy's post (the one I picked to start this thread with).

It seems that claiming 30 minutes by chopping off the part of the sentence that indicates 3 hours is a VERY deliberate attempt to mislead.

I'm trying to focus here. You can't just hand wave and say "never mind that, look over here".

I'm asking if the fires burned hot enough and long enough. We have some quote from NIST that seemed to say no, then they are shown to be taken out of context, and now you move to "it seems to me..."

Why not see what NIST actually said in context? What about the first part?

"Paragraph/Sentence: Section 3.4.5 Second to last paragraph. "Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel temperatures that were approximately 400º C or less, primarily due to the effects of thermal expansion. After 4 h of heating, there was substantially more damage and failures in the WTC 7 structural system than at 3.5 h of heating." And in the next paragraph: "However, it appeared likely the critical damage state occurred between 3.5 h and 4 h."

The 911Research piece suggests " it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C." but this is basically a lie. If you read the report (NCSTAR 1-A) it's very clear that they are talking about 3.5 hours into the simulation, not 3.5 hours of sustained 400C. They are very clear that the fire was not sustained in any one location for that long:

 

[Oxymoron]

I am asking how accurate is the analysis in Oxy's post (the one I picked to start this thread with).

It seems that claiming 30 minutes by chopping off the part of the sentence that indicates 3 hours is a VERY deliberate attempt to mislead.

I'm trying to focus here. You can't just hand wave and say "never mind that, look over here".

I'm asking if the fires burned hot enough and long enough. We have some quote from NIST that seemed to say no, then they are shown to be taken out of context, and now you move to "it seems to me..."

Why not see what NIST actually said in context? What about the first part?

"Paragraph/Sentence: Section 3.4.5 Second to last paragraph. "Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel temperatures that were approximately 400º C or less, primarily due to the effects of thermal expansion. After 4 h of heating, there was substantially more damage and failures in the WTC 7 structural system than at 3.5 h of heating." And in the next paragraph: "However, it appeared likely the critical damage state occurred between 3.5 h and 4 h."

The 911Research piece suggests " it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C." but this is basically a lie. If you read the report (NCSTAR 1-A) it's very clear that they are talking about 3.5 hours into the simulation, not 3.5 hours of sustained 400C. They are very clear that the fire was not sustained in any one location for that long:

Strange Mick, you criticise them for editorialising and then do it yourself... They actually say...

(Cole) comment: Exact input details of the NIST model were not provided for review. However, based on the above, it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C., or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.

Now I could say 'why leave out the first bit about NIST not providing input data which forces deductions to be made'?

But let's let that lay.

Where it says 'floor slabs have been removed for clarity'... what does that actually mean?

And what does it mean by 'heating of the lower 16 floors'

What is actually depicted here and how is it arrived at?

 

[Oxymoron]

[...]​

 

[Mick West]

Strange Mick, you criticise them for editorialising and then do it yourself... They actually say...

(Cole) comment: Exact input details of the NIST model were not provided for review. However, based on the above, it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C., or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.

Er, yes, the bit you quote there is what I was referring to. It's a lie, don't you agree?

It's their fire simulation. Calculating the spread of fire through the building. The floor slabs have been removed because otherwise it would be mess of white lines, it's just so you can see the heat map. It's showing how hot the lower 16 floors got. It's all explaining in NCSTAR 1-A

https://www.metabunk.org/files/NIST Building 7 final report 861610_unlocked.pdf

 

[Oxymoron]

Er, yes, the bit you quote there is what I was referring to. It's a lie, don't you agree?

Well it seems a cogent deduction from what NIST say... without knowing there input data.

It's their fire simulation.

Yep.. I got that bit

Calculating the spread of fire through the building.

What calculations did they use to come up with that depiction and those temperatures?

The floor slabs have been removed because otherwise it would be mess of white lines, it's just so you can see the heat map.

But it is saying up to floor 16. Now not all floors were alight up to 16 and only parts were alight at different times and entire floors were extinguished by being burnt out.
And I am trying to work out whether they are suggesting they took the floors out of the simulation which would be crazy as the floors would inhibit fire transfer and heat transfer. It may sound silly but I wouldn't put it past them to run that. I don't know what the depiction would look like with the floors included, in fact I can't see a method of showing the floors in an overhead view?

It's showing how hot the lower 16 floors got. It's all explaining in NCSTAR 1-A

https://www.metabunk.org/files/NIST Building 7 final report 861610_unlocked.pdf

Can you paste the explanation here because I can't find it?

 

[Mick West]

Well it seems a cogent deduction from what NIST say... without knowing there input data.

No, it seems like a blatant lie, or at best a serious error based on an out of context quote. They claim that NIST say that 3.5 hours of 400C is required, but NIST just says that the main damage occurred at 3.5 hours into the simulation. Totally different things.

Would you agree that this statement:

"it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C."

Is false?

And hence the rest of the 911Research excerpt you quoted is also false?

For an explanation of the simulation, you can start at section 3.4.3

3.4.3 Fire Dynamics Simulator (FDS)The major fires on Floors 7 through 9 and 11 though 13 in WTC 7 were simulated using the Fire
Dynamics Simulator (FDS), version 4, in a manner similar to the simulations conducted for WTC 1 and
WTC 2 (NIST NCSTAR 1-5F). There were far fewer photographs and videos of WTC 7 than of the
towers; and, thus, the details of the WTC 7 fires were not as precise as for the fires in the towers.
However, the imagery was sufficient to guide the WTC 7 fire simulations. Unlike the computations for
WTC 1 and WTC 2, the fire simulations for WTC 7 were conducted for each floor individually, as there
were no obvious pathways for the flames and heat to pass from one floor to another, aside from the
debris-damaged area in the southwest corner of the building (NIST NCSTAR 1-9, Chapter 9). The fires
on Floors 7, 8, and 12 were simulated using input from the visual imagery and established fire physics.
The fire on Floor 9 was similar to that on Floor 8, and the simulation was derived from it. For the same
reason, the fires on Floors 11 and 13 were derived from the fire on Floor 12. While use was made of the
appearance of flames and window breakage in photographs and videos in formulating the simulations, the
Investigation Team realized that the absolute timing of the simulations might not align exactly with the
timing of the fires on September 11, 2001. A typical single floor fire simulation took up to two days on a
Linux cluster with 8 processors.


Figure 3–5 shows hourly snapshots of the computed temperatures near the ceiling of the 8th floor. The
general clockwise movement of the fires is in agreement with the visual images. Figure 3–6 is a similar
visualization of the temperatures resulting from the computed fires on the 12th floor. The general
counterclockwise movement of the fires is evident.

Remember we are not yet talking about how accurate this simulation is. We are talking about if 911Research was correct in his claims.

 

[Oxymoron]

Ok... for clarity, your interpretation of what NIST are saying is 'the key structural fire damage, 'thermal expansion', happened in the last half hour'? Is that right?

That really seems like a no brainer... I would narrow it down even more than that and say the key damage happened in the last 5 mins.

Content from external source:

"Paragraph/Sentence: Section 3.4.5 Second to last paragraph. "Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel temperatures that were approximately 400º C or less, primarily due to the effects of thermal expansion. After 4 h of heating, there was substantially more damage and failures in the WTC 7 structural system than at 3.5 h of heating." And in the next paragraph: "However, it appeared likely the critical damage state occurred between 3.5 h and 4 h."

The 911Research piece suggests " it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C." but this is basically a lie. If you read the report (NCSTAR 1-A) it's very clear that they are talking about 3.5 hours into the simulation, not 3.5 hours of sustained 400C. They are very clear that the fire was not sustained in any one location for that long:

 

[George B]

Ok... for clarity, your interpretation of what NIST are saying is 'the key structural fire damage, 'thermal expansion', happened in the last half hour'? Is that right?

That really seems like a no brainer... I would narrow it down even more than that and say the key damage happened in the last 5 mins.

Wow! That must be it Oxy . . . I think you got the jest of it . . .

 

[Mick West]

Ok... for clarity, your interpretation of what NIST are saying is 'the key structural fire damage, 'thermal expansion', happened in the last half hour'? Is that right?

That really seems like a no brainer... I would narrow it down even more than that and say the key damage happened in the last 5 mins.

No. They ran a simulation starting with some fairly small fires at 1PM, and it ran for four hours to determine how it would spread, and what temperature things would get to. The key structural damage happened by 3.5 hours into the simulation. At some point there was a transition from heating and gradual failure (The ANSYS simulation) to the initiation of collapse (the LS-DYNA collapse). That's not the same thing as when the key damage was done. The key damage was done over a period of time, then there was a "key failure event", which combined with the damage up to that point triggered collapse.

NIST

Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th
floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel
temperatures that were approximately 400 °C (750 °F) or less, primarily due to the effects of thermal
expansion. After 4.0 h of heating, there was substantially more damage and failures in the WTC 7
structural floor systems than at 3.5 h of heating.


The ANSYS results were input to the LS-DYNA analysis when it appeared that an initial failure eventmight be imminent. Damage diagrams for the 16 floors modeled in ANSYS, such as those shown in
Figure 3–9, indicated some degree of uncertainty in selecting the time and damage state for the transition.
However, it appeared likely the critical damage state occurred between 3.5 h and 4 h. Accordingly, as
shown in the next section, LS-DYNA analyses were performed for both of these damage states.

So we've got two possibilites, which we can see here in this diagram.

The damage did not happen at any one point in time, just gradually in the time before collapse (although probably mostly in the hour before, note the significant difference between 3.5 and 4.0 hours).

It's clear from the fire simulation that there was a gradual accumulation of beam and girder failures, and connection failures. Eventually it became more than the structure could support, and a column failed, which led to a cascade of failures which brought down the building.

Let leave the accurace of the simulation aside for a second. I want to focus on the fact that the 911Research interpretation is a totally false representation of what NIST said.

 

[Oxymoron]

They are very clear that the fire was not sustained in any one location for that long:

No. They ran a simulation starting with some fairly small fires at 1PM,

This would suggest they are discounting fires prior to 1pm.

and it ran for four hours to determine how it would spread, and what temperature things would get to.

Ok, so this is the bit we are just supposed to accept without question... If we accept this, everything else works out?

The key structural damage happened by 3.5 hours into the simulation.

All I have seen is some hot spots moving around the building and not spending too long in one place because fire exhausted the fuel source within about 20 - 40 mins and moved on. Are NIST saying that the joints, girders and columns were damaged in each area progressively such that they were weakened enough to collapse without resistance?

At some point there was a transition from heating and gradual failure (The ANSYS simulation)

Like an event horizon?

to the initiation of collapse (the LS-DYNA collapse).That's not the same thing as when the key damage was done. The key damage was done over a period of time, then there was a "key failure event", which combined with the damage up to that point triggered collapse.

Which would be the failure of column 79?


NIST

Figure 3-9 shows an example of the extent of structural damage from the fires, in this case for the 13th
floor. At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel
temperatures that were approximately 400 °C (750 °F) or less, primarily due to the effects of thermal
expansion. After 4.0 h of heating, there was substantially more damage and failures in the WTC 7
structural floor systems than at 3.5 h of heating.


The ANSYS results were input to the LS-DYNA analysis when it appeared that an initial failure eventmight be imminent. Damage diagrams for the 16 floors modeled in ANSYS, such as those shown in
Figure 3–9, indicated some degree of uncertainty in selecting the time and damage state for the transition.
However, it appeared likely the critical damage state occurred between 3.5 h and 4 h. Accordingly, as
shown in the next section, LS-DYNA analyses were performed for both of these damage states.

So we've got two possibilites, which we can see here in this diagram.

The damage did not happen at any one point in time, just gradually in the time before collapse (although probably mostly in the hour before, note the significant difference between 3.5 and 4.0 hours).
It's clear from the fire simulation that there was a gradual accumulation of beam and girder failures, and connection failures. Eventually it became more than the structure could support, and a column failed, which led to a cascade of failures which brought down the building.

But in the diagram below...mostly in the hour before, is designated light blue, (200 -350 C), for most of the area, especially on the left hand side, (east) and south side.

So how do we know, (other than by the fact the building fell), that these columns, girders and trusses were fatally damaged in a moderate heat source which other buildings have withstood for hours and hours?

Let leave the accurace of the simulation aside for a second. I want to focus on the fact that the 911Research interpretation is a totally false representation of what NIST said.

I cannot agree with that assessment at this point.

 

[Mick West]

I cannot agree with that assessment at this point.

Then I'm not explaining it very well, sorry.

911Research makes two specific claims:

it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C., or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.

and:

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."

and conclude:

If the entire analysis of the initial failure event is dependent on temperatures approaching 400º C that must exist over 3.5 hour period, and/or the fires did not last that long in the critical Column 79 area, then the entire foundation of the simulation appears flawed. And if the input of the model is flawed, the output results and conclusions are also flawed.

But the problem is that both their claims, and hence their conclusion, are false.

Firstly, as I explain above, the 3.5 hour time was simply the time into the simulation at which a critical level of damage had occurred to the building as a whole. It was not the time any one piece of steel or any area had been exposed to a particular temperature. The diagram showing the spread of the fire makes this perfectly clear, as they show the fires moving through the building.

Secondly, they missed off the end of their NIST quote in the second claim, which was:

However, the large floor area surrounding Column 79 would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

Either one of these claims being false would have invalidated their conclusion. The fact that BOTH are false means it's entirely baseless.

 

[hiper]

The diagram showing the spread of the fire makes this perfectly clear, as they show the fires moving through the building.

This is absurd. You now de facto claim the whole building was ablaze.

 

[Mick West]

This is absurd. You now de facto claim the whole building was ablaze.

No I don't. I claim the fires were as observed, and likely as modeled.

But that's not the point. We are discussing the claims in the top post, and why I think they are false. Read my whole post above, and read NCSTAR 1-A

 

[Mick West]

This thread is to remain strictly on topic. Off topic posts will be deleted.

If you want to talk about something else, start a new thread.

 

[hiper]

[...]

 

[Ron J]

Yes to both. I posted here https://www.metabunk.org/posts/41014

The fires are not sufficiently hot or long enough to cause the collapse... let alone a 'uniform, straight down, collapse'... What are the chances of that happening BTW... Any statatitions like to come up with an odds for random office fires in a massive building causing a uniform collapse similar to a demolition.

I can see video of flames shooting out of the east wall of WTC7. Those floor to ceiling flames look hotter than 400 degrees. The east wing was where the collapse began.
From video shot on the north side of the building, it looked like the fire worked its way across pretty much the entire north face, from all the blown out windows on certain fire floors. It looks as if the fire worked its way across the area underneath the east penthouse.

Obviously there was insulation, which is where the 400 degree figure comes in, but maybe NIST miscalculated the amount of combustibles and thus the amount of heat that was generated by the fire in that particular area.

 

[Oxymoron]

Then I'm not explaining it very well, sorry.

No probs, I could say the same myself but I think it has more to do with our differing viewpoints.

If NIST were able to show a progression of which columns, beams and trusses failed where and when and what impact that had individually and cumulatively, we may get somewhere. But to simply say there was a fire which moved around causing damage as it went until it reached a particular column where it dislodged that column which then put more stress on other columns, so they failed; which led to a progressive collapse of other columns.... but all this happened within the building so no one could see it and no columns or girders broke out from the building to give an indication of what was happening inside... but then the whole exterior fell down uniformly looking like a demolition even though the internal damage caused by fires was completely random.

That doesn't cut it for me.

So can you point out any specific damage which NIST identified say an hour into the fire, ( 1 -2 pm would not be hot enough for any structural damage whatsoever as the temp is below 200 C for the first half hour), so I doubt anything much would have happened structurally to the girders by weakening or thermal expansion?

In the next hour... the fires were hotter according to NIST and situated on the east side between about 2 - 3 pm. Now staying with that area... are you saying that when the fire migrated and focused on the North/central area, (around 4pm), the east side would be cooling and steel would recover much of it's strength as it cooled?

Or are you saying that girders joints and trusses were wrecked by an hours fire and could not recover as they cooled and the fire migrated?

 

[Mick West]

No probs, I could say the same myself but I think it has more to do with our differing viewpoints.

If NIST were able to show a progression of which columns, beams and trusses failed where and when and what impact that had individually and cumulatively, we may get somewhere. But to simply say there was a fire which moved around causing damage as it went until it reached a particular column where it dislodged that column which then put more stress on other columns, so they failed; which led to a progressive collapse of other columns.... but all this happened within the building so no one could see it and no columns or girders broke out from the building to give an indication of what was happening inside... but then the whole exterior fell down uniformly looking like a demolition even though the internal damage caused by fires was completely random.

That doesn't cut it for me.

So can you point out any specific damage which NIST identified say an hour into the fire, ( 1 -2 pm would not be hot enough for any structural damage whatsoever as the temp is below 200 C for the first half hour), so I doubt anything much would have happened structurally to the girders by weakening or thermal expansion?

In the next hour... the fires were hotter according to NIST and situated on the east side between about 2 - 3 pm. Now staying with that area... are you saying that when the fire migrated and focused on the North/central area, (around 4pm), the east side would be cooling and steel would recover much of it's strength as it cooled?

Or are you saying that girders joints and trusses were wrecked by an hours fire and could not recover as they cooled and the fire migrated?

We can get into that, but I want to hear if I've adequately explained my objection to your quote from 911Research, and if you agree that what 911Research said was incorrect.

 

[Cairenn]

[...]

 

[Oxymoron]

We can get into that, but I want to hear if I've adequately explained my objection to your quote from 911Research, and if you agree that what 911Research said was incorrect.

I have very seriously considered your argument but I cannot make sense of it no matter how I try.

Perhaps we can break it down further.

You suggest at https://www.metabunk.org/posts/42254

911Research makes two specific claims:

Content from external source:

it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C., or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.




and:

Content from external source:

In addition, according to Page 330 Section 8.4.1 (NCSTAR 1-9 Vol. 1): "Prediction and growth of building contents fires (Chapter 9) indicated that such fires did not persist at any one location for more then about 20 min to 30 min., which is consistent with observations of fires in the windows (Chapter 5)."





and conclude:

Content from external source:

If the entire analysis of the initial failure event is dependent on temperatures approaching 400º C that must exist over 3.5 hour period, and/or the fires did not last that long in the critical Column 79 area, then the entire foundation of the simulation appears flawed. And if the input of the model is flawed, the output results and conclusions are also flawed.




But the problem is that both their claims, and hence their conclusion, are false.

I agree that if either or both premises are wrong, then the conclusion is likely wrong.

The problem is, IMO, you have not demonstrated either premise to be false.

I suggest we deal with each claim individually, starting with this one.

it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C.,

I suggest this is an accurate and proven statement. Can you specify exactly what you deem false about it and why?

NB I note your rebuttal using the NIST quote but please specify the exact part which clearly and unambiguously rebuts the above statement

The argument is then transliterated as;

or to put it another way, any time less then 3.5 hours or 4 hours would not cause a failure.

This seems an entirely reasonable interpretation with the caveat of temperatures in excess of 400 C.

Is this the part that you consider false?

 

[Mick West]

Right. They claim:

it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C.

That is making the claim that each connection that failed needed to be heated at 400C for 3.5 hours.

Yet the simulation shows the fire moving around, and what NIST is says is simply the time at which a critical amount of failures has happened. 3.5 hours into the simulation. NIST does not say that a connection needs to be heated at 3.5 hours at 400C in order to fail.

Really simple: 3.5 hours into the simulation is not the same as 3.5 hours at 400C

It's just 3.5 hours of the building being on fire.

See the problem here is that you said "The fires are not sufficiently hot or long enough to cause the collapse...", and you then quoted the 911Research piece as evidence of this. However the 911Research Piece is just misinterpreting the NIST report. The NIST report very clearly DOES say the fires burned long and hot enough.

 

[Mick West]

I understand this is perhaps a little complicated, and difficult to communicate. But I think it's very importnat to drill down to these fundamental errors. Once you introduce an error into your argument, and then base other things upon it, then it's corrupted your entire argument. And yet the error then becomes so deeply enmeshed in your argument that it's difficult to back away from it.

It also illustrate how easy it is to take things out of context, and how important it is to look at the entirety of the original source, and to understand that source. It's a trivial matter to pick a couple of quotes that seem contradictory - it's harder to read and understand the NIST report so you can see what the quotes mean in context and why they are not contradictory. This imbalance in difficulty is largely responsible for the longevity of the controlled demolition theory.

 

[Oxymoron]

Right. They claim:

it appears the modeling effort to reach failure mode of the connections required was at least a time of 3.5 hours at a temperature of approximately 400º C.

That is making the claim that each connection that failed needed to be heated at 400C for 3.5 hours.

Yet the simulation shows the fire moving around, and what NIST is says is simply the time at which a critical amount of failures has happened. 3.5 hours into the simulation. NIST does not say that a connection needs to be heated at 3.5 hours at 400C in order to fail.

Really simple: 3.5 hours into the simulation is not the same as 3.5 hours at 400C

It's just 3.5 hours of the building being on fire.

See the problem here is that you said "The fires are not sufficiently hot or long enough to cause the collapse...", and you then quoted the 911Research piece as evidence of this. However the 911Research Piece is just misinterpreting the NIST report. The NIST report very clearly DOES say the fires burned long and hot enough.

But that makes no sense Mick. It appears you are saying that 3.5 hours into the simulation... undisclosed or all connections will magically fail wherever they are in the building and irrespective of how hot they have gotten or for how long they have been at that temp.

Ergo, even a connection that has little or no fire will collapse at that point 'due to fire damage'... It is illogical.

BTW, I don't think they are saying that all connections that failed had to be fire damaged for 3.5 hours. But those that were not would fail at different rates due to different forces transferred and imposed by those that did collapse. in which case you would not expect a symmetrical collapse at nearly free fall speed. More likely a partial collapse on one side.

 

[Mick West]

But that makes no sense Mick. It appears you are saying that 3.5 hours into the simulation... undisclosed or all connections will magically fail wherever they are in the building and irrespective of how hot they have gotten or for how long they have been at that temp.

Ergo, even a connection that has little or no fire will collapse at that point 'due to fire damage'... It is illogical.

No, that's not what I'm saying.

The connections fail gradually, one by one, over time. Different connections fail at different times as the fire moves and grows. Each connection requires a certain individual exposure to high temperature in order to fail.

Eventually (somewhere around the 3.5 to 4.0 hour point in the simulation) enough connections have failed that column 79 has lost lateral support (support from the sides, which keeps it straight), and it buckles and fails.

It's like playing Jenga (a game where you make a tower of blocks, and then removed them one at a time, trying not to be the person who makes the tower fall). One connection failing (on block removed) does not make the tower fall. But as you remove more and more the tower (column 79) becomes more and more unstable. Eventually it's so unstable that pretty much removing any block will make it topple (buckle and fail).

All the 3.5 hours number is saying is that after 3.5 hours of simulated fire in the building, column 79 was just weakly supported, and ready to fail. After 4.0 hours it was really weakly supported. At some point it buckled.

 

[Oxymoron]

No, that's not what I'm saying.

The connections fail gradually, one by one, over time. Different connections fail at different times as the fire moves and grows. Each connection requires a certain individual exposure to high temperature in order to fail.

Eventually (somewhere around the 3.5 to 4.0 hour point in the simulation) enough connections have failed that column 79 has lost lateral support (support from the sides, which keeps it straight), and it buckles and fails.

It's like playing Jenga (a game where you make a tower of blocks, and then removed them one at a time, trying not to be the person who makes the tower fall). One connection failing (on block removed) does not make the tower fall. But as you remove more and more the tower (column 79) becomes more and more unstable. Eventually it's so unstable that pretty much removing any block will make it topple (buckle and fail).

All the 3.5 hours number is saying is that after 3.5 hours of simulated fire in the building, column 79 was just weakly supported, and ready to fail. After 4.0 hours it was really weakly supported. At some point it buckled.

Ok, so you are suggesting that as the fire traveled, it fatally damaged columns and connections in each area in a short time frame of under an hour, (like removing jenga blocks), until it reached column 79 and when column 79 gave way the interior of 7 collapsed because there was little left holding it up?

Is there anywhere in the NIST report that says connections, columns, beams etc will be critically damaged by fire around the 400C mark in 20 to 30 mins which is apparently NISTS estimation of how long the fire remained in different locations?

And further, if that is what NIST meant, why did they not say it?

 

[Mick West]

Ok, so you are suggesting that as the fire traveled, it fatally damaged columns and connections in each area in a short time frame of under an hour, (like removing jenga blocks), until it reached column 79 and when column 79 gave way the interior of 7 collapsed because there was little left holding it up?

Not exactly. Column 79 itself was not damaged much by the fire, nor were the other columns. It was their lateral support (the horizontal girders, and their connections) that were gradually damaged, one girder or connection at a time.

Is there anywhere in the NIST report that says connections, columns, beams etc will be critically damaged by fire around the 400C mark in 20 to 30 mins which is apparently NISTS estimation of how long the fire remained in different locations?

But that's not what they said, as was explained earlier. 911Research left off this bit from their NIST quote:

However, the large floor area surrounding Column 79 would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

And further, if that is what NIST meant, why did they not say it?

They did. Just 911Research misquoted and misinterpreted them.

 

[George B]

Not exactly. Column 79 itself was not damaged much by the fire, nor were the other columns. It was their lateral support (the horizontal girders, and their connections) that were gradually damaged, one girder or connection at a time.



But that's not what they said, as was explained earlier. 911Research left off this bit from their NIST quote:

However, the large floor area surrounding Column 79 would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

They did. Just 911Research misquoted and misinterpreted them.

Mick . . . in the area simulated there was not a uniform distribution of fire and stress . . . the real question is what was required to weakened or compromise a connection and/or support beam and were enough compromised? Also, there is a question as to once heat is sufficient for weaken in 20 - 30 minutes but the heat is then lessened or removed because there is no more fuel . . . does any structural strength return?

 

[Oxymoron]

Not exactly. Column 79 itself was not damaged much by the fire, nor were the other columns. It was their lateral support (the horizontal girders, and their connections) that were gradually damaged, one girder or connection at a time.

Does NIST make that distinction? Can you paste it?

But that's not what they said, as was explained earlier. 911Research left off this bit from their NIST quote:

However, the large floor area surrounding Column 79 would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.

This is completely irrelevant to your argument which on your interpretation doesn't even need extended duration in any one spot and which NIST even acknowledge... did not occur. Further 'could' is a pretty big assumption... there 'could' have been thermite there but what the heck without evidence it doesn't exist right?

They did. Just 911Research misquoted and misinterpreted them.

No, you just said it... that is your interpretation of what they said and 911Research and I and others interpret it differently. What we need to establish is 'because they have been so appallingly vague... what exactly were they trying to say'? That can only be done, (if at all) by an in depth analysis and debate.

But you must admit, NIST is extremely vague and ambiguous which is what everyone who questions 9/11 is moaning about and up in arms about.

 

[Mick West]

Is there anywhere in the NIST report that says connections, columns, beams etc will be critically damaged by fire around the 400C mark in 20 to 30 mins which is apparently NISTS estimation of how long the fire remained in different locations?

A bit more on this

Besides the obvious problem that NIST actually said the firs burned around col 79 (and hence the connections to col 79) for two hours. There's the issue of "400C", which comes from this quote:

At both 3.5 h and 4.0 h, connections, floor beams, and girders were damaged or had failed at steel temperatures that were approximately 400º C or less, primarily due to the effects of thermal expansion.

So the questions are:

A) How long goes it take to get to 400C?
B) How long does it take for thermal expansion sufficient to damage the member?

NCSTAR 1-A, page 21:

As the fires progressed, some of the structural steel began to heat. According to the generally acceptedtest standard, ASTM E-119, one of the criteria for establishing the fire resistance rating for a steel column
or floor beam is derived from the time at which, during a standard fire exposure, the average column
temperature exceeds 538 °C (1000 °F) or the average floor beam temperature exceeds 593 °C (1100 °F).
These are temperatures at which there is significant loss of steel strength and stiffness. Due to the
effectiveness of the SFRM, the highest column temperatures in WTC 7 only reached an estimated 300 °C
(570 °F), and only on the east side of the building did the floor beams reach or exceed about 600 °C
(1100 °F). The heat from these uncontrolled fires caused thermal expansion of the steel beams on the
lower floors of the east side of WTC 7, primarily at or below 400 ºC (750 ºF), damaging the floor framing
on multiple floors.


The initiating local failure that began the probable WTC 7 collapse sequence was the buckling of
Column 79. This buckling arose from a process that occurred at temperatures at or below approximately
400 °C (750 °F), which are well below the temperatures considered in current practice for determining
fire resistance ratings associated with significant loss of steel strength. When steel (or any other metal) is
heated, it expands. If thermal expansion in steel beams is resisted by columns or other steel members,
forces develop in the structural members that can result in buckling of beams or failures of connections.

Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of
Floor 13, which triggered a cascade of floor failures. In this case, the floor beams on the east side of the
building expanded enough that they pushed the girder spanning between Columns 79 and 44 to the west
on the 13th floor. (See Figure 1–5 for column numbering and the locations of girders and beams.) This
movement was enough for the girder to walk off of its support at Column 79.

NCSTAR 1-9 page 84:

Which shows that 400C is reached for all beams in under an hour (3600 seconds), and for the lower flange of some, in under 20 minutes.

How long does it take to expand? Well with gradual heating like that, the expansion happens with the heating - directly in proportion, so by the time it's at 400C, it has thermally expanded. For ever 1 degree rise in temperature it expands. Nothing magical happens at 400C.

 

[George B]

Mick, where in the NIST report do they specify how hot and how long it takes to have a lateral connection fail? Remember theses were covered in fire proofing material. . . no aircraft collision separated the fireproofing from the columns, etc. . .

 

[Mick West]

Does NIST make that distinction? Can you paste it?

Yes, they make the distinction MANY times. Here's one detailed example in the context of the original quotes:

8.4.1 Column Failure by Heating
Heating of a column could occur as a result of a building contents fire, or as had been suggested, from a
diesel fire resulting from rupture of a fuel line supplying one of several emergency generators in the
building. Prediction of growth and spread of building contents fires (Section 9.3.2) indicated that such
fires moved from one location to the next (e.g., from one office cubicle to the next) and burned intensely
in any one location for roughly 20 min to 30 min. However, the large floor area surrounding Column 79
would have had sufficient combustibles (i.e., cubicles) to support fires in that area for two to three hours.
A diesel fuel fire could also have occurred in the vicinity of Column 79, but analyses have shown
(Section 9.2) that the duration of such a fire would be limited to less than two hours.

A thermal analysis was conducted of Column 79, typical of the geometry found on lower floors, i.e., a
W14x730 section with cover plates and thermal insulation (see Chapter 9). Based on the knowledge that
the yield strength of steel is reduced to roughly 50 percent of its room temperature value at steel
temperatures of around 500 ºC to 600 ºC, it was found that it would take roughly 6 h of continuous
exposure from a fully developed fire (gas temperatures of around 1100 ºC) to reach these temperatures.
Therefore, it would not have been possible for a building contents fire to have heated a massive, insulated
column such as Column 79 to the point of failure.

Sections 9.2 and 8.9.1 show that the worst-case scenarios associated with ruptured fuel lines generated
fires that could not be sustained long enough, would have produced too little heat to raise the
temperatures of the steel to the point of significant loss of strength, and/or would have led to the flowing
of smoke out the ventilation louvers, which contradicts the visual evidence.


8.4.2 Column Failure by Loss of Lateral Support (increased unbraced length)

Floors that frame into a column provide lateral support to the column. If a building had a regular floor-tofloor
height, h, then failure of one floor would result in an unbraced column length of 2h. Likewise,
failure of two floors would result in an unbraced column length of 3h, and so on. If a sufficient number
of floors were to fail, the column could buckle even if it were not weakened by heating. This simple
explanation assumes that the load on a column remains constant. In reality, the load on a column can
change as fires grow and spread and non-uniformly heat the steel frame. Such load redistribution is
accounted for in the analyses conducted in this investigation. The possibility of floor failure in fire is
explored in detail in later sections of this chapter.

They then go into vast detail, and more simply state in the summary:

3. Initial Local Failure for Collapse Initiation. Fire-induced thermal expansion of the floor
system surrounding Column 79 led to collapse of Floor 13 that triggered a cascade of floor
failures. This, in turn, led to loss of lateral support to Column 79 over nine stories, resulting in
the buckling failure of Column 79.

This is completely irrelevant to your argument which on your interpretation doesn't even need extended duration in any one spot and which NIST even acknowledge... did not occur. Further 'could' is a pretty big assumption... there 'could' have been thermite there but what the heck without evidence it doesn't exist right?

They did not say "could", they say "would". It would have had sufficient combustibles. I don't agree it's irrelevant, because my argument here is that the 911Research quotes are incorrect. Also the graphs I just posted show it can take an hour to reach 400C.

No, you just said it... that is your interpretation of what they said and 911Research and I and others interpret it differently. What we need to establish is 'because they have been so appallingly vague... what exactly were they trying to say'? That can only be done, (if at all) by an in depth analysis and debate.

But you must admit, NIST is extremely vague and ambiguous which is what everyone who questions 9/11 is moaning about and up in arms about.

The NIST reports are very long and complex. I think this can perhaps come across as "vague" as it is sometimes difficult to find information in them. But in this particular case they are quite precise about what they know, and what they do not know, and the range of uncertainty. But again, the point I'm making here is that the 911Research excerpt is wrong. It does not support your assertion that the fires did not burn long enough, and it's so wrong it seems like a deliberate attempt to mislead.

 

[Mick West]

Mick, where in the NIST report do they specify how hot and how long it takes to have a lateral connection fail? Remember theses were covered in fire proofing material. . . no aircraft collision separated the fireproofing from the columns, etc. . .

See above. 400C, about an hour. But actual events are quite complex.

Remember I'm trying to keep this focused on the claims in the first post here. Please look at that again, and my objections to it.