NIST's Pellets

[uk_dave]

What about the rthings the plane debris hits?

Were the floors of the WTC open pplan, or subdivided with partitions? What about desks and chairs? What about movement of the structure from the impact?

Vibration?

Blast?

There are countless things which could dislodge or damage the fireproofing. Fireproof materials tend to be very rigid. They have no flexibility.

How much damage was caused to the heat resistant tiles on columbia by that falling lump of foam insulation?

How deep is the sea? How high is the sky?

 

[rwguinn]

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.



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.

\
Are you familiar with the phrase "A chain is only as strong as its weakest link?"
All you have to do is heat a portion of a beam element (Column or truss)and you have weakened the whole thing.
Think of stress as flowing like a river. At corners, narrow places, and hot areas, it piles up, and can break thru. If that area excedes it allowable stress, it fails--and the load bearing element will no longer bear the load.

 

[aggle-rithm]

2. Agreed also, but the NIST doesn't mention it as the primary reason of why wasn't the insulation there.

Because the evidence that the forces involved were sufficient to dislodge the insulation was better than the evidence (purely circumstantial) that the insulation in the impact zone wasn't installed correctly.

I mention it because, although the evidence of faulty insulation is circumstantial, it is at least consistent with the evidence, unlike practically any alternate CT theory.

 

[Arkan_Wolfshade]

dangnabbit, my memory sucks. Who was it around here that has actually done fire testing, in a residential environment iirc?

 

[Gravy]

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?

Rather than referring to the executive summary, you really need to look at the details of the NIST report on passive fire protection (1-6A). It's 274 pages. In appendix C, you can see photos of the impact test results on the SFRM. A small impact against a flat piece of steel repeatedly dislodges a large section of SFRM.

 

[Gravy]

dangnabbit, my memory sucks. Who was it around here that has actually done fire testing, in a residential environment iirc?

Dave 46.

 

[Arkan_Wolfshade]

Dave 46.

Danke

 

[aggle-rithm]

Danke

No, "Dave".

 

[Yurebiz]

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.

If it didn't pierce through, and it then has only dislodged parts of the exterior columns of roughly one side of the tower, barely including any core clomuns at all, then how can it become a global collapse? How were the fires which spread across the floors any relevant at all, if the many other steel beams did not have time to heat up above 250C?

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




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

Wrong.

Start over.

Do not make the same mistake again.

I do not refute that the plane smashed away the fireproofing at the crash site. I'm asking how could it dislodge the insulations through the floors, and the floors above.

Sad thing is, I do not find any analysis of fire displacement throughout the floors. I ask you please to be patient with me, and consider that such a thread about this subject has not been made before. Please also consider that this is not a minor subject, and I'm not just "nit-picking". This is an open discussion and you may "disprove" me as you wish.

For the two of you: We agree the NIST primarily blames the fire for weakening the steel, and initiating a global collapse due to bending trusses pulling the exterior columns inwards, don't we?

Do you agree that the fireproofing would have to be at least 50% dislodged throughout the floors at the impact zone, and throughout at least 5 floors above, for it to support a global collapse initiation thesis?

Had it been only in the crash zone, the fires that spread would not be relevant, since it would not have been enough time to heat the steel throughout the floors above 250C. It would not support a global collapse conclusion as I see it.

 

[Gravy]

Whatever floors were on fire, It would have minor significance, had the steel not been dislodged, as you know.

No. we don't know that, because NIST says nothing of the sort. Try not to put words in our mouths and theirs. NIST never said the fires would have been of "minor significance" had SFRM not been dislodged. They said their models show that the towers probably wouldn't have fallen if the SFRM had been intact. Which means that they possibly could have fallen with intact SFRM.

JREFer Architect posted links to interesting reports by highly-respected fire engineers who conclude that the towers could have fallen from the fires alone. Their studies may not have been as thorough as NIST's but they're worth a read.

 

[jaydeehess]

I've mentioned it before that any portion of a column or beam that was bared of insulation and then heated would conduct that heat to cooler portions of the member BUT since those cooler portions still have their insulation intact(as in on another floor) heat cannot be radiated easily away from the member.

Thus if a significant amount of insulation is removed at one fire floor and the same column retains insulation elsewhere along its length that can be a worse situation than if all the insulation along its entire length was removed.

The impact debris would have been moving in one basic direction although secondary and tertiary collisions would occur as the debris ricocheted around in other directions. There is also the explosion of the jet fuel which would propel debris in all directions as well as cause damage to the insulation directly by the pressure wave.

NIST's study did not take into account every mode by which the SFRM could be dislodged and therefore as Horatius showed (albeit loudly ) NIST established a "lower bound on the bared steel surface area".

 

[Gravy]

If it didn't pierce through, and it then has only dislodged parts of the exterior columns of roughly one side of the tower, barely including any core clomuns at all, then how can it become a global collapse? How were the fires which spread across the floors any relevant at all, if the many other steel beams did not have time to heat up above 250C?

If it didn't pierce through? What in the world are you talking about?

I do not refute that the plane smashed away the fireproofing at the crash site. I'm asking how could it dislodge the insulations through the floors, and the floors above.

The collapse initiation zone is what matters.

Sad thing is, I do not find any analysis of fire displacement throughout the floors.

There's only about a thousand pages of that in the NIST reports.

 

[Yurebiz]

Because the evidence that the forces involved were sufficient to dislodge the insulation was better than the evidence (purely circumstantial) that the insulation in the impact zone wasn't installed correctly.

I mention it because, although the evidence of faulty insulation is circumstantial, it is at least consistent with the evidence, unlike practically any alternate CT theory.

Agreed. But if there was any significant evidence at all that it wasn't installed correctly, I'm sure the NIST would include it. They would not miss any chance to further support their computer simulations.

\
Are you familiar with the phrase "A chain is only as strong as its weakest link?"
All you have to do is heat a portion of a beam element (Column or truss)and you have weakened the whole thing.
Think of stress as flowing like a river. At corners, narrow places, and hot areas, it piles up, and can break thru. If that area excedes it allowable stress, it fails--and the load bearing element will no longer bear the load.

There were many chains of trusses and columns. Yes, they are all interconnected, but the heat transfer isn't fast enough to transfer 600C+ heat over 5 floors, under about an hour. Even thought i agree that for each beam there isn't much dislodgement necessary for it to be susceptible to the fires, I am certain that it would be necessary for over 50% of the beams, be it trusses or columns, around the floors, to be dislodged at all, for it to support the global collapse scenario.
Besides, had the heat transfer been more rapid, it would work against this scenario. The beams wouldn't heated at all, because the heat would be transfered to the floors below, and the concentrated heat around the 5 floors of the crash zone would be less intense. The more heat transfer assumed, the less bowing it should occur

Rather than referring to the executive summary, you really need to look at the details of the NIST report on passive fire protection (1-6A). It's 274 pages. In appendix C, you can see photos of the impact test results on the SFRM. A small impact against a flat piece of steel repeatedly dislodges a large section of SFRM.

I'll immediately take a look at it.

 

[jaydeehess]

How were the fires which spread across the floors any relevant at all, if the many other steel beams did not have time to heat up above 250C

By this you seem to be saying that all columns had to be heated to a plastic stage for the collapse to be global.

try this then, assuming you own your home. Take the interior drywall off so that you can get to the studs. Now remove every fourth one around the exterior of the house and along any load bearing wall. Now start randomly removing others and see whether or not it requires you to remove all but one in order for the house to fall down.

 

[Yurebiz]

No. we don't know that, because NIST says nothing of the sort. Try not to put words in our mouths and theirs. NIST never said the fires would have been of "minor significance" had SFRM not been dislodged. They said their models show that the towers probably wouldn't have fallen if the SFRM had been intact. Which means that they possibly could have fallen with intact SFRM.

JREFer Architect posted links to interesting reports by highly-respected fire engineers who conclude that the towers could have fallen from the fires alone. Their studies may not have been as thorough as NIST's but they're worth a read.

Blue is insulated, Red is not insulated.
As you see, had the steel had not been dislodged, the fires would have failed to heat the steel above 250C. thus being insignificant whether they occurred or not, since the steel still maintains roughly 80% of it's original strength.
That is from.. Page 80, final report 1-1
I don't know why the text didn't come out as well. Damn converter.

 

[jaydeehess]

There were many chains of trusses and columns. Yes, they are all interconnected, but the heat transfer isn't fast enough to transfer 600C+ heat over 5 floors, under about an hour.

GEEZUS man why would it have to? All that would berequired is that columns be damged at various floors. IE column 'a' damaged on floor 'xx' column 'b' damaged on floor 'yy' etc. and have all the floors in question be relatively close. The collapse will initiate basically at one floor due to the increased loads on all columns but in different locations. Does not the mind boggle at the chaotic redistribution of loads in such a case as the towers?

 

[rwguinn]

Agreed. But if there was any significant evidence at all that it wasn't installed correctly, I'm sure the NIST would include it. They would not miss any chance to further support their computer simulations.



There were many chains of trusses and columns. Yes, they are all interconnected, but the heat transfer isn't fast enough to transfer 600C+ heat over 5 floors, under about an hour. Even thought i agree that for each beam there isn't much dislodgement necessary for it to be susceptible to the fires, I am certain that it would be necessary for over 50% of the beams, be it trusses or columns, around the floors, to be dislodged at all, for it to support the global collapse scenario.
Besides, had the heat transfer been more rapid, it would work against this scenario. The beams wouldn't heated at all, because the heat would be transfered to the floors below, and the concentrated heat around the 5 floors of the crash zone would be less intense. The more heat transfer assumed, the less bowing it should occur



I'll immediately take a look at it.

Whot the H3ll?
I suggest you go back, read the report, then take a class in, say, materialsscience, another one in Statics, and at least a class in dynamics.
If you weaken a 6" long chunk of a steel column by 50%, and don't increase the load on it, it will fail at 50% of design load.
You cah heat a 2' long piece of steel to melting point at one end, holding it in your bare hand at the other end, and weld it to another piece of steel using a charcoal fire and a fan.
why do you need to heat the whole thing up?
I call troll, possibly socks.

 

[Gravy]

Yes, they are all interconnected, but the heat transfer isn't fast enough to transfer 600C+ heat over 5 floors, under about an hour. Even thought i agree that for each beam there isn't much dislodgement necessary for it to be susceptible to the fires, I am certain that it would be necessary for over 50% of the beams, be it trusses or columns, around the floors, to be dislodged at all, for it to support the global collapse scenario.

I have no idea why you're making the false assumption that 5 floors of steel had to heat to "600C+" in order for the collapses to occur. The collapse initiation floors are what matter. Note where the exterior columns are bowed in the most: that's where the collapses started.

 

[Yurebiz]

Whot the H3ll?
I suggest you go back, read the report, then take a class in, say, materialsscience, another one in Statics, and at least a class in dynamics.
If you weaken a 6" long chunk of a steel column by 50%, and don't increase the load on it, it will fail at 50% of design load.
You cah heat a 2' long piece of steel to melting point at one end, holding it in your bare hand at the other end, and weld it to another piece of steel using a charcoal fire and a fan.
why do you need to heat the whole thing up?
I call troll, possibly socks.

I have seen, in these same forums, some graphs which show that the thermal transfer withing the trusses (at least the trusses, I doubt the columns would be any different at that though) was not sufficient to cool it down so it wouldn't bow down. It was a debunking against a CTer who said the "fire transfer should have been enough so the whole towers wouldn't heat up so quickly in just one hour", or something similar. If you really insist on that, I'll try bringing the graphs up here.

 

[Yurebiz]

I have no idea why you're making the false assumption that 5 floors of steel had to heat to "600C+" in order for the collapses to occur. The collapse initiation floors are what matter. Note where the exterior columns are bowed in the most: that's where the collapses started.

Gravy do you not think that the other sides, and the central cores would have to at least be heated above 250+ for a global collapse as fast as those to happen? One side is enough?

GEEZUS man why would it have to? All that would berequired is that columns be damged at various floors. IE column 'a' damaged on floor 'xx' column 'b' damaged on floor 'yy' etc. and have all the floors in question be relatively close. The collapse will initiate basically at one floor due to the increased loads on all columns but in different locations. Does not the mind boggle at the chaotic redistribution of loads in such a case as the towers?

How would they be damaged, had the insulation not been dislodged? If it's only due to progressive load transfer, then stop blaming the fires then. The plane made a Huge gapping hole on roughly one whole side of the towers, plus a few core columns. That was probably enough to knock them down, then.