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NIST's Pellets

Yurebiz

Thinker
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Joined
Jan 13, 2007
Messages
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So I was watching Kevin Ryan's comments on the allegation that the plane could have had the same effect on the steel insulation at the WTC Twin Towers. I have used the search function and sadly haven't been able to find any rebuttal against this argument, besides ad hominem on Kevin. My question is, how likely is it that a Boeing 767, while crashing into the towers, could have dislodged the fireproofing from the trusses and columns, in the same manner as 0.3 in pellets traveling at 350mph? If it's somehow likely, then is there any peer-reviewed paper available, in which the assertion can be proven possible?

I find it amusing that this haven't been discussed before. Because, you know, Kevin Ryan has been saying this stuff for a while, and the NIST does rely on the dislodging of fireproof to support their computer simulations and global collapse initiation conclusions. The NIST does say, that if it wasn't for that, the towers might have not collapsed. This is an important factor that I feel it wasn't touched, analyzed deep enough. Please share your thoughts.

Below is the quote directly from the NIST NCSTAR1, page 169
6.9.3 Damage to Thermal Insulation
The dislodgement of thermal insulation from structural members could have occurred as a result of
(a) direct impact by debris and (b) inertial forces due to vibration of structural members as a result of the
aircraft impact. The debris from the aircraft impact included the fragments that were formed from both
the aircraft (including the contents and fuel) and the building (structural members, walls, and furnishings).
In interpreting the output of the aircraft impact simulations, NIST assumed that the debris impact
dislodged insulation if the debris force was strong enough to break a gypsum board partition immediately
in front of the structural component. Experiments at NIST confirmed that an array of 0.3 in. diameter
pellets traveling at approximately 350 mph stripped the insulation from steel bars like those used in the
WTC trusses.
Determining the adherence of SFRM outside the debris zones was more difficult. There was
photographic evidence that some fraction of the SFRM was dislodged from perimeter columns not
directly impacted by debris.
NIST developed a simple model to estimate the range of accelerations that might dislodge the SFRM
from the structural steel components. As the SFRM in the towers was being upgraded with BLAZE-
SHIELD II in the 1990s, The Port Authority had measured the insulation bond strength (force required to
pull the insulation from the steel). The model used these data as input to some basic physics equations.
The resulting ranges of accelerations depended on the geometry of the coated steel component and the
SFRM thickness, density and bond strength. For a flat surface (as on the surface of a column), the range
was from 20g to 530g, where g is the gravitational acceleration. For an encased bar (such as used in the
WTC trusses), the range was from 40g to 730g. NIST estimated accelerations from the aircraft impacts of
approximately 100g.
In determining the extent of insulation damage in each tower, NIST only assumed damage where
dislodgement criteria could be established and supported through observations or analysis. Thus, NIST
made the conservative assumption that insulation was removed only where direct debris impact occurred
and did not include the possibility of insulation damage or dislodgement from structural vibration. This
assumption produced a lower bound on the bared steel surface area, thereby making it more difficult to
heat the steel to the point of failure.
Click to expand...
Bolding mine.
 
Yurebiz said:
Bolding mine.
Click to expand...

6.9.3 Damage to Thermal Insulation
The dislodgement of thermal insulation from structural members could have occurred as a result of
(a) direct impact by debris and (b) inertial forces due to vibration of structural members as a result of the
aircraft impact. The debris from the aircraft impact included the fragments that were formed from both
the aircraft (including the contents and fuel) and the building (structural members, walls, and furnishings).
In interpreting the output of the aircraft impact simulations, NIST assumed that the debris impact
dislodged insulation if the debris force was strong enough to break a gypsum board partition immediately
in front of the structural component. Experiments at NIST confirmed that an array of 0.3 in. diameter
pellets traveling at approximately 350 mph stripped the insulation from steel bars like those used in the
WTC trusses.
Determining the adherence of SFRM outside the debris zones was more difficult. There was
photographic evidence that some fraction of the SFRM was dislodged from perimeter columns not
directly impacted by debris.
NIST developed a simple model to estimate the range of accelerations that might dislodge the SFRM
from the structural steel components. As the SFRM in the towers was being upgraded with BLAZE-
SHIELD II in the 1990s, The Port Authority had measured the insulation bond strength (force required to
pull the insulation from the steel). The model used these data as input to some basic physics equations.
The resulting ranges of accelerations depended on the geometry of the coated steel component and the
SFRM thickness, density and bond strength. For a flat surface (as on the surface of a column), the range
was from 20g to 530g, where g is the gravitational acceleration. For an encased bar (such as used in the
WTC trusses), the range was from 40g to 730g. NIST estimated accelerations from the aircraft impacts of
approximately 100g.
In determining the extent of insulation damage in each tower, NIST only assumed damage where
dislodgement criteria could be established and supported through observations or analysis. Thus, NIST
made the conservative assumption that insulation was removed only where direct debris impact occurred
and did not include the possibility of insulation damage or dislodgement from structural vibration. This
assumption produced a lower bound on the bared steel surface area, thereby making it more difficult to
heat the steel to the point of failure.
Click to expand...

Perhaps you should read more than the parts you bolded.

NIST did more than just the shotgun test. They based models on tests done with the actual materials that were actually used on the actual steel in the actual building. They observed actual portions of the steel with the actual insulation actually removed.

And even with all that, they made conservative estimates of how much insulation was removed.

And even with all that, if you look around, Architect has some links to studies which actually disagree with NIST, which shows that even with the insulation unaffected, the fires would still have caused a collapse under these circumstances.

So with all that, do you still think nitpicking one test is going to make the whole argument collapse?
 
I'd be happy to be proven wrong on this one. May you please link me to those reports?
 
Since you've read the NIST report, you must have seen the photos of the SFRM that was blasted off the exterior columns. Of course there are no photos of the interior, but do you really think that if an airliner traveling at high speed exploded into this structure, along with demolished office contents,it wouldn't remove fire insulation?

879045b67406862b1.jpg


Below are two examples of fire inslulation knocked off of steel columns and beams at 130 Liberty street, which was hit by debris only.
​


879045b674072231e.jpg


879045b674075d6ad.jpg

​
 
Consider this:
The above is a clearly defined experiment and provides a null hypothesis. Anyone willing to spend the money can reproduce the experiment and observe the results.

So, for the sake of discussion, let's assume that the experiment is reproduced with the same results. The question then becomes, is it a valid model of what occurred in the towers?
0.30" diameter shot is buckshot
[table=""]Size|Diameter|Pellets/oz
1|.30"(7.6 mm)|10|[/table]
http://en.wikipedia.org/wiki/Shotgun#Shot

350 mph = ~513 fps

Now, Remington's buckshot load, of #1 buck, in a 12 ga has the following stats:
http://www.remington.com/products/ammunition/shotshell/buckshot/express.asp
[table=""]Index No.|Gauge|Shell Length|Velocity (ft/sec@3ft)|Shot Size|Pellet Count
12B1|12|2 3/4"|1250|1|16[/table]

Now, Remington has a slick little energy calculator here: http://www.remington.com/products/ammunition/bullet_energy.asp

To use it, you need to know how many grains are in an oz: 437.5 grains

So, if there are 10 pellets in 1 oz of of #1 buckshot (per wiki article) we determine that each pellet is 1/10 oz or .1 oz 0.1 oz = 43.75 grains

Using the Remington calculator for their shot load, we see each pellet has
A bullet with a weight of 43.7 grains and a velocity of 1250 feet per second would produce approximately:

152 ft. lbs. energy
Click to expand...
Now, doing the same for the NIST test, each pellet has
A bullet with a weight of 43.7 grains and a velocity of 513 feet per second would produce approximately:

26 ft. lbs. energy
Click to expand...


That's it. 26 ft. lbs. of energy is sufficient to dislodge the insulation. When put in these terms, does it seem quite as incredulous as before?
 
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Is there a reason to suspect that this does not represent, to a significant level, the effect on the SFRM of the aircraft and office furnishings debris?

I rather doubt that there are any other similar tests that anyone has done since this would not be considered as a factor in the designing of the SFRM application.

NIST will have some justification for using the pellets they did, probably somehwere in the same report. What is the url for this report?
Now obviously larger debris, say 10 inches accross, denser objects and faster travelling objects would have a greater effect in stripping insulation than smaller ones. NIST would be using a median size and density and using a velocity that is probably conservative, for the pellets to be similar in effect as the debris.
 
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DavidJames said:
Proven wrong about what. I don't see any claims in your original post.
Click to expand...
The claim is that it is impossible for an Aluminum 7n7 aircraft, traveling at 550 MPH and hitting a steel-and-air building, would break up into small pieces that keep traveling at some speed less than 550 MPH.

Gosh, haven't you learned to read CT yet?
 
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rwguinn said:
The claim is that it is impossible for an Aluminum 7n7 aircraft, traveling at 550 MPH, would break up into small pieces that keep traveling at some speed less than 550 MPH.

Gosh, haven't you learned to read CT yet?
Click to expand...

[typing sheepishly]like thinking 4th dimensionally, I have problems with that
 
Gravy said:
Since you've read the NIST report, you must have seen the photos of the SFRM that was blasted off the exterior columns. Of course there are no photos of the interior, but do you really think that if an airliner traveling at high speed exploded into this structure, along with demolished office contents,it wouldn't remove fire insulation?
Click to expand...

I do not deny the fire insulation could have been "knocked off" directly at the plane crash. The steel beams itself have been blown away at the crash site, I don't doubt that adjacent beams might have been damaged.

However, the NIST uses this as a pretext for it's global collapse thesis. It says that most of the steel beams, at the plane crash and above, had to have been dislodged, for the fire to have any effect for a fire which has been going on for about an hour. Without dislodged insulation, the fires don't mean anything in such a sudden collapse, as their graphs say. And such dislodgement is primarily blamed on the plane crashes.

My question, if I may reformulate, is how did the plane remove the majority of insulation around so many steel beams as such to help a global collapse? The only simulation I've seen is that of the shotgun pellets shot at insulation foams.

By the way, I haven't read the NIST report yet, I've only jumped to it a couple pages just so to confirm what Kevin was arguing against was really on the document...

Oh my, so much to quote. Hold on :o
 
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Yurebiz said:
I do not deny the fire insulation could have been "knocked off" directly at the plane crash. The steel beams itself have been blown away at the crash site, I don't doubt that adjacent beams might have been damaged.

However, the NIST uses this as a pretext for it's global collapse thesis. It says that most of the steel beams, at the plane crash and above, had to have been dislodged, for the fire to have any effect for a fire which has been going on for about an hour. Without dislodged insulation, the fires don't mean anything in such a sudden collapse, as their graphs say. And such dislodgement is primarily blamed on the plane crashes.

My question, if I may reformulate, is how did the plane remove the majority of insulation around so many steel beams as such to help a global collapse? The only simulation I've seen is that of the shotgun pellets shot at insulation foams.
Click to expand...


Perhaps you're assuming that a steel member has to reach a high temperature along its whole length before it can fail?

However, imagine a wooden beam on two posts with a fire in the middle. Do you think the whole beam would have to be fully aflame before it fails, or would concentrated fire at the mid point cause failure without the whole beam being consumed?
 
Arkan_Wolfshade said:
Consider this:
The above is a clearly defined experiment and provides a null hypothesis. Anyone willing to spend the money can reproduce the experiment and observe the results.

So, for the sake of discussion, let's assume that the experiment is reproduced with the same results. The question then becomes, is it a valid model of what occurred in the towers?
0.30" diameter shot is buckshot
[...]
That's it. 26 ft. lbs. of energy is sufficient to dislodge the insulation. When put in these terms, does it seem quite as incredulous as before?
Click to expand...

I appreciate this model, but I'm not debating whether there was enough energy to dislodge it. You haven't taken in account how much would be necessary (hell, I actually forgot to research that and bring it up before posting, but I guess we'll figure it out eventually) to dislodge the so many steel beams around the fire zones so it would support a global collapse.

Besides, Even if there is enough energy to directly displace the foams, theres still the question on how did the small plane debris has uniformly pierced through the walls, the floor concrete, all living load materials in the offices, and got through up to the steel beams.

jaydeehess said:
Is there a reason to suspect that this does not represent, to a significant level, the effect on the SFRM of the aircraft and office furnishings debris?

I rather doubt that there are any other similar tests that anyone has done since this would not be considered as a factor in the designing of the SFRM application.

NIST will have some justification for using the pellets they did, probably somehwere in the same report. What is the url for this report?
Now obviously larger debris, say 10 inches accross, denser objects and faster travelling objects would have a greater effect in stripping insulation than smaller ones. NIST would be using a median size and density and using a velocity that is probably conservative, for the pellets to be similar in effect as the debris.
Click to expand...

Over here: http://wtc.nist.gov/reports_october05.htm
I haven't been able to find it out by myself yet, but that's another reason why i created such a thread, because this haven't been thoroughly discussed before here. On a single thread, at least.
 
Yurebiz said:
My question, if I may reformulate, is how did the plane remove the majority of insulation around so many steel beams as such to help a global collapse? The only simulation I've seen is that of the shotgun pellets shot at insulation foams.
Click to expand...

1. It wouldn't be necessary to remove the MAJORITY of the insulation.
2. If the towers were like a lot of modern buildings, the insulation in that area may have been poorly installed in the first place.
 
uk_dave said:
Perhaps you're assuming that a steel member has to reach a high temperature along its whole length before it can fail?

However, imagine a wooden beam on two posts with a fire in the middle. Do you think the whole beam would have to be fully aflame before it fails, or would concentrated fire at the mid point cause failure without the whole beam being consumed?
Click to expand...
In a short period of time, I would expect that each beam would have to be at least 3 or 4 feet of dislodgement in length, for the fires to be able to heat it up throughly. But my questions still rests at how where they dislodged at all. I can understand fire spreading across floors, I just can't understand how "pellets" were flying around dislodging the beams. Whatever floors were on fire, It would have minor significance, had the steel not been dislodged, as you know. Actually that's a nice (CT) way to put it: Fires spread across floors, but so does 350mph plane debris?
 
aggle-rithm said:
1. It wouldn't be necessary to remove the MAJORITY of the insulation.
2. If the towers were like a lot of modern buildings, the insulation in that area may have been poorly installed in the first place.
Click to expand...
1. Agreed.
2. Agreed also, but the NIST doesn't mention it as the primary reason of why wasn't the insulation there.
 
Yurebiz said:
Besides, Even if there is enough energy to directly displace the foams, theres still the question on how did the small plane debris has uniformly pierced through the walls, the floor concrete, all living load materials in the offices, and got through up to the steel beams.
Click to expand...

My question would be, how do you crash an airliner into a building at hundreds of mph and NOT have it contact the steel frame?

It did not need to UNIFORMLY pierce through the walls, and didn't need to pierce the floors at all.

Clearly, the towers didn't collapse uniformly. There was visible tilting at the beginning of the collapse, which tended to correct itself as it progressed. This "correction" was due to the simple fact that the downward force of gravity on the moving section was greater than the ability of the lower sections to resist it/and or push it to one side.
 
Yurebiz said:
However, the NIST uses this as a pretext for it's global collapse thesis. It says that most of the steel beams, at the plane crash and above, had to have been dislodged, for the fire to have any effect for a fire which has been going on for about an hour. Without dislodged insulation, the fires don't mean anything in such a sudden collapse, as their graphs say. And such dislodgement is primarily blamed on the plane crashes.

My question, if I may reformulate, is how did the plane remove the majority of insulation around so many steel beams as such to help a global collapse? The only simulation I've seen is that of the shotgun pellets shot at insulation foams.
Click to expand...

No it doesn't say that. That's the whole point. They don't say that. Read the thing:


In determining the extent of insulation damage in each tower, NIST only assumed damage where dislodgement criteria could be established and supported through observations or analysis. Thus, NIST made the conservative assumption that insulation was removed only where direct debris impact occurred and did not include the possibility of insulation damage or dislodgement from structural vibration. This assumption produced a lower bound on the bared steel surface area, thereby making it more difficult to heat the steel to the point of failure.
Click to expand...

How much clearer can I make this? They simply do not claim what you assert they claim. You're just wrong. Completely, totally, unambiguously wrong.

Wrong.

Start over.

Do not make the same mistake again.
 
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aggle-rithm said:
2. If the towers were like a lot of modern buildings, the insulation in that area may have been poorly installed in the first place.
Click to expand...

Too true. I've worked around some spray on fireproofing that if you bumped it too hard whole sections of it peeled off. Also many times portions are removed during either initial construction or later renovation and never replaced.
 
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