Gage's next debate

[Sunstealer]

? if it was pre fab stuff, put some sulfur between layers. if i remember right, prof jones thinks the red grey chips might have been used as "matches" to ignite thermXte.

Wait, now there are more layers than the gray layer and the red layer? Can you show anyone this multiple layering containing Sulphur? Jones only found bi-layered chips. One layer is iron oxide most likely either rusted steel or MIO (fig 31 & 33 also show non-metallic gray layer too!). The red layer is the supposedly thermite. They do not claim thermate. Now all of a sudden it's used as a match! Do you know why that is a stupid idea?

You don't so I'll tell you. ThermAte is thermIte with Sulphur added. The temperature of ignition is going to be identical if not LOWER than thermite due to the reaction between Sulphur and Aluminium so there is no benefit in igniting thermate with thermite - you will have to get the temperature just as high if not higher to ignite thermite - it's pointless.

Can you not see that Jones is adding layer upon layer of unnecessary complication because his findings do not support the corrosion mechanism observed? No ofcourse not.

He claims thermite - then it's pointed out you need sulphur for a Fe-0-S eutectic - so then he adds Sulphur to his claim even though his own study; Harrit et al, doesn't find this.

the point is that it showed the same "characteristic corrosion as found by Barnett et al. in WTC 7 steel."

Sorry, but until we see the data then his claim is invalid. We know Jones et al don't have a clue so we need to see data for the claim so we can compare. I asked for a link to the data and you didn't provide it. Why not?

Bearing in mind Jones hasn't actually read the Harrit et al paper in full - he can't have because if he did he would have realised this. It also shows how incompetent they were. They had a sample of Tnemec red primer paint but didn't realise it instead claiming thermite.

Yes corrosion of this severity is unusual, however, in order to get this type of corrosion to occur temperatures must be elevated for significant periods of time. We are talking days.

Do you understand what solid state diffusion is?

Do you know what a parabolic rate constant is?

Do you know which parameters dictate diffusion of Sulphur (or for that matter any gas) into the surface of steel?

Do you know what carburisation is, why it's used and how metallurgists can calculate how deep a "case depth" can be made given time, temperature, partial pressure etc. Why is case hardening (carburising) performed at 925°C and above?

If you researched carburising then you would come to understand why the diffusion of Sulphur takes days given the corrosion we see.

There is also the possibility of liquid metal embrittlement (LME) taking place LME cracking is mm/s - very fast. You may also wish to look up the term "Hot Shortness" and read up on why Manganese is added to steel. It's entirely possible that we are seeing hot shortness in this instance.

Show me a thermite/thermate that will burn for more than an hour. (Infact more than a 10 minutes would be a feat) I'll guarantee you can't. It's simple reaction kinetics. You really should read up on a subject fully before jumping to the wrong conclusion.

 

[triforcharity]

Does anyone know about curtain-fall collapses in fires? This I got from Vincent Dunn's book on Fire Safety. Looks like this may describe the Building 7 perimeter collapse, except that it's masonry/brick materials so my question --- would this kind of collapse scenario apply in a steel-framed building with perimeter columns?

Curtain-Fall Collapse

In this type of collapse, the exterior masonry wall drops like a falling curtain cut loose at the top. The wall crumbles and falls straight down, with brick and mortar forming a pile on the ground near the base of the wall. The collapse of the brick veneer, brick cavity, or masonry-backed stonewall often occurs in a curtain-fall manner. If the metal ties holding a brick veneer wall to plywood backing are destroyed by fire, or if mortar bonding between an exterior finished stonewall and a masonry backing wall is washed away by hose streams, large sections of brick or stone veneer may fall off the building's exterior. Firefighters entering, leaving, or operating near the doorways beneath the curtain-fall collapse may be killed or seriously injured by falling brick.

Another situation of potential curtain-fall collapse occurs when fire has collapsed the interior of a multi-story brick-and-joist structure and the remaining free-standing walls have many window openings with brick arches serving as linters. If one of the masonry walls starts to fall and the brick arches spanning the tops of the wall openings crumble and fall apart, the wall will fall downward rather than straight out.

Maybe an entirely different mechanism is at play here, but it's interesting to see that very fast "curtain-fall" collapses do happen in fires, not just in CD. Does curtain-fall sound like free-fall, or am I reading too much into this?

Chris,

I have seen this type of collapse before. Vincent Dunn is incredibly smart, and one of the most respected firefighter instructors out there.

Here is the book that the passage appears in.
http://books.google.com/books?id=0h...wAA#v=onepage&q=curtain fall collapse&f=false

This is the type of collapse Vincent is talking about.

http://www.youtube.com/watch?v=4wfpRO9bTfo

Here is another.

http://www.youtube.com/watch?v=DZ1e3ddf3RM

Now, I can't find the training video I have of a true curtain fall collapse, but I will try to find it asap.

No, it is not the same as what happened on 9/11. Not at all.

But, I am going to assume that it could have a freefall period, as in the second video, but curtain fall and freefall are not the same.

 

[Christopher7]

I think Chris is right here. My understanding is that NIST didn't look carefully at thermal contraction after the sagged steel beams cooled off a bit when the fire burned out in some regions of the building.

The collapse was triggered by thermal expansion, not thermal contraction.

[FONT=&quot]NCSTAR 1A pg 22 [pdf pg 64][/FONT]
[FONT=&quot]Fire-induced thermal expansion[/FONT][FONT=&quot] 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. This movement was enough for the girder to walk off of its support at Column 79. [/FONT]

[FONT=&quot]The unsupported girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the 5th floor [/FONT]

 

[triforcharity]

Hey Chris7,

There is a post here that you should view.

 

[ElMondoHummus]

Bearing in mind Jones hasn't actually read the Harrit et al paper in full - he can't have because if he did he would have realised this. It also shows how incompetent they were. They had a sample of Tnemec red primer paint but didn't realise it instead claiming thermite.

Wait, huh? Which Jones? Stephen? I thought he was the co-author of that work. Or is there another Harrit paper out there I'm not aware of?

Or... are you saying that Jones didn't even read the material one of his co-authors contributed? That I could see.

 

[Senenmut]

Wait, now there are more layers than the gray layer and the red layer? Can you show anyone this multiple layering containing Sulphur? Jones only found bi-layered chips. One layer is iron oxide most likely either rusted steel or MIO (fig 31 & 33 also show non-metallic gray layer too!). The red layer is the supposedly thermite. They do not claim thermate. Now all of a sudden it's used as a match! Do you know why that is a stupid idea?

its called speculation. prof jones found chips with multiple layers. was this stuff sprayed on or was it pre fabricated meaning it could came in multiple layers and rolled out onto the steel. if it came say 10 layers thick, one could easily put a layer of sulfur down then more layers of the red grey chip material then sulfur and so on...

You don't so I'll tell you. ThermAte is thermIte with Sulphur added. The temperature of ignition is going to be identical if not LOWER than thermite due to the reaction between Sulphur and Aluminium so there is no benefit in igniting thermate with thermite - you will have to get the temperature just as high if not higher to ignite thermite - it's pointless.

yeah. its speculation.

Can you not see that Jones is adding layer upon layer of unnecessary complication because his findings do not support the corrosion mechanism observed? No ofcourse not.

but he did state that this experiment exhibited the same corrosion characteristics that barnett found regarding the wtc 7 steel:
"I (with colleagues) have done the experiment with thermite + sulfur (often called "thermate") acting on a piece of WTC steel. In fact, I did the experiment with BBC filming it! Then we looked at the steel, including use of electron microscopy, and found the same characteristic corrosion as found by Barnett et al. in WTC 7 steel. OTOH, I know of no expt done to test whether gypsum and heat would have this effect -- I would be VERY surprised, as the sulfur in gypsum is not elemental Sulfur, but is bound as a sulfate (very difficult to reduce to suflur.) We should do the latter experiment to rule out such nonsense. If you can provide direct quotes from the BBC program on this point, it may prove useful in a research note on the subject."

 

[Christopher7]

Hey Chris7,

There is a post here that you should view.

I read it, so what?

They used the results in their model.

NCSTAR 1-9 Vol.1 pg 353
This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses.


The slab was heated in the fire so this data does not represent what actually happened.

 

[Animal]

I read it, so what?

They used the results in their model.

NCSTAR 1-9 Vol.1 pg 353
This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses.


The slab was heated in the fire so this data does not represent what actually happened.

"Consider a simple floor beam-to-girder arrangement as found" in the northeast corner of WTC7

In-plane restraint of the floor slab restrained expansion. This boundary condition is assumed for illustrative purposes and to produce a maximum force in the shear studs. This simple analysis helped to determine whether or not the failure of shear studs needs to be accounted for in the detailed ANSYS analysis of the lower 16 stories of WTC 7 (Chapter 11). In the detailed finite element analysis, the floor slabs were not restrained and the heating of the concrete slab and steel beams was determined by thermal analysis (Chapter 10).

 

[Christopher7]

Does anyone know about curtain-fall collapses in fires? This I got from Vincent Dunn's book on Fire Safety. Looks like this may describe the Building 7 perimeter collapse, except that it's masonry/brick materials so my question --- would this kind of collapse scenario apply in a steel-framed building with perimeter columns?

It wasn't just the curtain wall, it was the entire upper portion of the building.

[FONT=&quot]NCSTAR 1A pg 55 [pdf pg 97][/FONT]
[FONT=&quot]The entire building above the buckled-column region then moved downward in a single unit, as observed[/FONT]

"[FONT=&quot]a free fall time would be an object that has no structural components below it"[/FONT]
[this is axiomatic]
Do you think that the upper portion in the top graphic will fall at FFA, as the one on the bottom would?

http://img851.imageshack.us/img851/1647/bucklingvnothing.jpg

Changed image to link. Stop re-posting the same image over and over again.

Replying to this modbox in thread will be off topic  Posted By: LashL

Triforcharity: The roof line descended 3 feet at the NW corner and 7 feet in the center as the columns buckled. The buckled column region had to be removed to permit FFA. Buckling columns provide resistance and preclude FFA.

 

[Christopher7]

In the Chandler and NIST graphs the roof line descends, pauses, and then goes into free fall acceleration. That cannot happen when columns are buckling, it can only happen if they are removed.

 

[funk de fino]

it is comparing what they expected to see ( distortion and bending--but not holes) to 15.9mm of a36 steel gone in 8 days.

Show us the steel with holes.

 

[funk de fino]

It wasn't just the curtain wall, it was the entire upper portion of the building.

[FONT=&quot]NCSTAR 1A pg 55 [pdf pg 97][/FONT]
[FONT=&quot]The entire building above the buckled-column region then moved downward in a single unit, as observed[/FONT]

"[FONT=&quot]a free fall time would be an object that has no structural components below it"[/FONT]
[this is axiomatic]
Do you think that the upper portion in the top graphic will fall at FFA, as the one on the bottom would?

[qimg]http://img851.imageshack.us/img851/1647/bucklingvnothing.jpg[/qimg]

Triforcharity: The roof line descended 3 feet at the NW corner and 7 feet in the center as the columns buckled. The buckled column region had to be removed to permit FFA. Buckling columns provide resistance and preclude FFA.

Read the part above again. Stop being dishonest.

 

[Christopher7]

Read the part above again.

I have read it. Did you read this?

The roof line descended 3 feet at the NW corner and 7 feet in the center as the columns buckled. The buckled column region had to be removed to permit FFA. Buckling columns provide resistance and preclude FFA.

 

[Carlos]

It would appear that Christopher believes that if a fire goes out on floor 12, the damage caused by the fire is fixed automatically.

Also known as Volwerine's Effect.

 

[triforcharity]

but he did state that this experiment exhibited the same corrosion characteristics that barnett found regarding the wtc 7 steel:
"I (with colleagues) have done the experiment with thermite + sulfur (often called "thermate") acting on a piece of WTC steel. In fact, I did the experiment with BBC filming it! Then we looked at the steel, including use of electron microscopy, and found the same characteristic corrosion as found by Barnett et al. in WTC 7 steel. OTOH, I know of no expt done to test whether gypsum and heat would have this effect -- I would be VERY surprised, as the sulfur in gypsum is not elemental Sulfur, but is bound as a sulfate (very difficult to reduce to suflur.) We should do the latter experiment to rule out such nonsense. If you can provide direct quotes from the BBC program on this point, it may prove useful in a research note on the subject."

And you're STILL missing the point. Jones et al. do not claim to have FOUND thermAte, they claim to have found thermIte.

Do you STILL not understand the problem??

 

[triforcharity]

I read it, so what?

They used the results in their model.

NCSTAR 1-9 Vol.1 pg 353
This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses.


The slab was heated in the fire so this data does not represent what actually happened.

Nice handwave and shift of subjects.

What does this have to do with Benzene?

 

[Carlos]

I have read it. Did you read this?

The roof line descended 3 feet at the NW corner and 7 feet in the center as the columns buckled. The buckled column region had to be removed to permit FFA. Buckling columns provide resistance and preclude FFA.

Strictly speaking, even a toothpick provide resistance.

 

[triforcharity]

In the Chandler and NIST graphs the roof line descends, pauses, and then goes into free fall acceleration. That cannot happen when columns are buckling, it can only happen if they are removed.

[qimg]http://img857.imageshack.us/img857/5822/graphcompare.jpg[/qimg]

How much resistance does a buckled column provide?

 

[Christopher7]

"Consider a simple floor beam-to-girder arrangement as found" in the northeast corner of WTC7

In-plane restraint of the floor slab restrained expansion. This boundary condition is assumed for illustrative purposes and to produce a maximum force in the shear studs. This simple analysis helped to determine whether or not the failure of shear studs needs to be accounted for in the detailed ANSYS analysis of the lower 16 stories of WTC 7 (Chapter 11). In the detailed finite element analysis, the floor slabs were not restrained and the heating of the concrete slab and steel beams was determined by thermal analysis (Chapter 10).

That's what I responded to. NIST said: "This boundary condition is assumed for illustrative purposes and to produce a maximum force in the shear studs.

But they used the results in their ANSYS model.

They created a test to get the result they wanted but that is not what happened in the fire. The slab was heated at the same time the beams were heated.

 

[Christopher7]

How much resistance does a buckled column provide?

The columns were buckling in a random manner so some were providing more resistance than others. I don't know what the formula is for a typical exterior column [[FONT=&quot]W14x500] [/FONT]but the buckling columns were providing resistance into the period of FFA. i.e. The NIST model does not depict the event.