The question for chek

[chek]

I think the investigators used the term "compression wave". It was essentially the compressed air pushed down the the ground and outward by the collapsing building.

This is interesting because many CT'ers deny that such a compression wave existed, because it is an alternate explanation for the "squibs" seen shooting out the sides of the towers as they collapsed.

The sight of those 'debris flows' not dispersing into the surrounding air, but 'boiling' as if a separate entity would suggest that there is more going on than compressed air blowing dust out of the way.

You still haven't addressed the point that even Hoffman's latest published calculation would require 250,000 litres of available water on every floor to produce the steam to generate this so-called pyroclastic flow (which it wasn't, despite John White wetting himself because somebody has slipped it into Wikipedia unnoticed)

I think you mean for every 10 floors - 2.3 million litres of water being his calculated agent of expansion.
Hoffman agrees that it is a hard figure to account for - and yet something had to drive that expansion, which occurred.
As he states the amount of sublimated water in the concrete and gypsum is an unknown (now that the evidence has been disappeared) and even the bodies of the victims struggles to account for that.

There is also the water available in the fire suppression system and the plumbing system to be taken into account, though they haven't been quantified anywhere I can find.
FEMA also points out 25000 litres of water storage and a 3750 litre per minute supply from the public water supply.

http://64.233.183.104/search?q=cache:F5 ... =clnk&cd=1

Perhaps v.4 of his paper will be more forthcoming with better information.

[chek]

Can a blazing oil storage depot roughly with an area approx. ten times bigger than the WTC site really be considered comparable to 3 buildings collapsing into dust and smouldering fires?

We started where I asked you whether dust collected from sheltered spots well away from GZ could give an accurate picture of the size and amount of concrete debris at GZ. So far you've skirted the issue.
You first ....

I thought I answered that in the second post I made in this thread:
"While critics will argue the exact percentage, the amount of solid concrete chunks is noticeably lacking even at GZ, (discounting rubble from WTC5 & 6)."
I agree it is not satisfactorily quantified, but show me where anyone has attempted to do so. All photographic evidence shows macro rubble to be conspicuous by its scarcity.

[ComfortablyNumb]

he he

Nice 1 Wiki

Thanks - thought I'd made an arse of myself!

[Ignatz]

You still haven't addressed the point that even Hoffman's latest published calculation would require 250,000 litres of available water on every floor to produce the steam to generate this so-called pyroclastic flow (which it wasn't, despite John White wetting himself because somebody has slipped it into Wikipedia unnoticed)

I think you mean for every 10 floors - 2.3 million litres of water being his calculated agent of expansion.
Hoffman agrees that it is a hard figure to account for - and yet something had to drive that expansion, which occurred.

As he states the amount of sublimated water in the concrete and gypsum is an unknown (now that the evidence has been disappeared) and even the bodies of the victims struggles to account for that.

There is also the water available in the fire suppression system and the plumbing system to be taken into account, though they haven't been quantified anywhere I can find.
FEMA also points out 25000 litres of water storage and a 3750 litre per minute supply from the public water supply.

http://64.233.183.104/search?q=cache:F5 ... =clnk&cd=1

Perhaps v.4 of his paper will be more forthcoming with better information.

You're correct it was every ten floors.
The FEMA report states 'several 5,000 gallon tanks'. Let's call it 10 making 50,000galls or approx 200,000 litres. Double that for local cisterns and pipes making 400,000.
(The 750 gals per minute refers to the capacity of the pump, not any rate of flow that was actually occuring)
Adding in 50% of the water content of the concrete (which I'd say is insanely generous, given that they weren't recovering the elements of concrete, but concrete itself even if was dust) brings us up to around 800,000.

Then a high proportion of the 'free' water would have to be vapourised as the building came down, and thermate (and derivatives) is essentially an incendiary with a low radius of action (which is one of the reasons its useful in its place), so you're still left with finding a mechanism to explain the boiling of the water, even if you can conjure up enough water.

Sorry chek, but once again your argument goes like this:

"Prof Jones says it was pyroclastic flow.
Evidence to the contrary must be wrong.
Apparent lack of a plausible mechanism means that one will come along shortly when Hoffman has tidied up his calculations."

i.e. faith-based

Hoffman's methodology and calculations have been horribly wrong so far. I wouldn't pin your hopes on him.

Meanwhile Greening has produced a worthy study at http://911myths.com/WTCREPORT.pdf
which - among many other things - explains that progressive collapse alone would do the job of pulverising large amounts of the concrete in the floors of the building.

[ian neal]

Also, keep in mind, 600,000 tons is a gross overestimate of the amount of concrete in each tower.

Do you have an alternative calculation or estimate?

I was curious to see if this is true or not.

So here is my strictly back of the envelope calculation, that whilst it doesn't match Hoffman's calculation is in the same ball park, the same order of magnitude.

Assumptions for ball park calculation. Please correct since I'm doing this from memory

Concrete density 2.4 MT/m3 of concrete

Concrete volume principally consists of 110 concrete floors depth 10cm (4in). Ignores concrete used in stairs and lift shafts in the central core

Floor dimensions 100m x 100m

Based on these assumptions, the weight of concrete in each tower would equal approximately

110 x 100 x 100 x 0.1 x 2.4 = 264,000 MT

[John White]

I think the investigators used the term "compression wave". It was essentially the compressed air pushed down the the ground and outward by the collapsing building.

This is interesting because many CT'ers deny that such a compression wave existed, because it is an alternate explanation for the "squibs" seen shooting out the sides of the towers as they collapsed.

The sight of those 'debris flows' not dispersing into the surrounding air, but 'boiling' as if a separate entity would suggest that there is more going on than compressed air blowing dust out of the way.

You still haven't addressed the point that even Hoffman's latest published calculation would require 250,000 litres of available water on every floor to produce the steam to generate this so-called pyroclastic flow (which it wasn't, despite John White wetting himself because somebody has slipped it into Wikipedia unnoticed)

I can have a chuckle without compromising bladder control: I'll let you know when I laugh that hard

This is straightforward sophistry and false labeling of the evidance

The debris cloud from the Towers collapse is a pyroclastic flow: it cannot be mistaken or confused for something else, it has signature characteristics

I was chuckling at wiki having the cheek to stick one to the ptb with the entry there

The fact remains: pyroclastic flows: observed in volcanic eruptions and explosive demolitions:

Not non explosive collapses: not in any other circumstance at all!

Co-incidence theorist: "It looks like a duck, walks like a duck and quacks like a duck (pyroclastic flow). Must be a hamster!"

[Ignatz]

The fact remains: pyroclastic flows: observed in volcanic eruptions and explosive demolitions:

Not non explosive collapses: not in any other circumstance at all!

Co-incidence theorist: "It looks like a duck, walks like a duck and quacks like a duck (pyroclastic flow). Must be a hamster!"

Then propose a mechanism to produce it.
Hoffman has failed for obvious reasons.

[John White]

The fact remains: pyroclastic flows: observed in volcanic eruptions and explosive demolitions:

Not non explosive collapses: not in any other circumstance at all!

Co-incidence theorist: "It looks like a duck, walks like a duck and quacks like a duck (pyroclastic flow). Must be a hamster!"

Then propose a mechanism to produce it.
Hoffman has failed for obvious reasons.

no no sir: after you

[chek]

Sorry chek, but once again your argument goes like this:

"Prof Jones says it was pyroclastic flow.
Evidence to the contrary must be wrong.
Apparent lack of a plausible mechanism means that one will come along shortly when Hoffman has tidied up his calculations."

i.e. faith-based

Hoffman's methodology and calculations have been horribly wrong so far. I wouldn't pin your hopes on him.

Meanwhile Greening has produced a worthy study at http://911myths.com/WTCREPORT.pdf
which - among many other things - explains that progressive collapse alone would do the job of pulverising large amounts of the concrete in the floors of the building.

I have to point out that evidence for attributing the description of pyroclastic flow comes less from 'direction by the leadership (what leaders?) than from the behaviour of the flow as seen on video, and the descriptions provided by witnesses as to its density and heat. The characteristics are a close match to known observations, even if not quite as energetic as the volcanic sources we are used to.

Even were the WTC towers to have been stuffed full to the gills with C4 and thermate powder, it would only be a fleabite compared to the energy and heat from Mount St. Helens or Mt. Pinatubo.

I'd be interested in what the 'evidence to the contrary' is. Describing it as merely airborne particles in ambient air would not account for the visible lack of dispersion observed in the first few minutes.

Perhaps Hoffman is trying his level best to account for as many natural phenomena as possible without resorting too readily to the super-heated expansion that explosives would help account for, but that's only my conjecture.

I would also trust Hoffman (is that faith based?) because of his readiness
to re-explore his conclusions in the light of new and less estimated evidence. That strikes me as evidence of his integrity in determining a realistic answer to a puzzle that nobody else has addressed, rather than defending an initial position dogmatically.

The math used in such calculations are beyond me to contribute to or understand in anything other than outline form (i.e. I'm not in a position to notice that a 'plus' should be a 'minus' or somesuch, but given his increased appreciation of defining the problems he has acquired over the past few years it's not unreasonable to see what his new paper reveals.
I believe (more faith) that he is motivated to discover rather than to cover up.

I remember checking the Greening paper some time ago, and if I recall the problem I had with it was that it didn't explain the total pulverisation of the topmost storeys, which gravity alone would have to account for.
Perhaps there's a fallacy there I'm not seeing that you could point out.

[ComfortablyNumb]

I'm gonna stick my neck out.

My big problem with the 'pancake theory' or whatever you wish to call it is symmetry. For the continuance of the process there would need to be equal downward pressure on all joints around all sides.

For example, the collapse of WTC1 is shown to be very uneven but appears to be able to 'level itself'.

My feel is as soon as there is an uneven pressure on one side then the momentum is skewed to that side and 'skips off' into the street, stopping the process. However, my only concern with is idea is the effect of the core. Does it keep the symmetry?

This has definitely no sign of presenting equal amounts of downward force. Does it?

[aggle-rithm]

I'm gonna stick my neck out.

My big problem with the 'pancake theory' or whatever you wish to call it is symmetry. For the continuance of the process there would need to be equal downward pressure on all joints around all sides.

For example, the collapse of WTC1 is shown to be very uneven but appears to be able to 'level itself'.

My feel is as soon as there is an uneven pressure on one side then the momentum is skewed to that side and 'skips off' into the street, stopping the process. However, my only concern with is idea is the effect of the core. Does it keep the symmetry?

I've heard a structural engineer discussing this, but I don't remember where. He said that a collapsing skyscraper will tend to level itself as it falls because it is not designed to support its own weight once it is rotated beyond a certain point. The engineers do not have to do anything special to make this happen; they just DON'T provide the extra support that would be needed to support a diagonal load.

This seems intuitively correct to me. Imagine a skyscraper laying on its side. The support structures exist to transfer the mass of the building down to its base at the ground. For it to stay in one piece laying on its side, ADDITIONAL supports would need to be added to transfer the weight laterally.

I know this is an absurd scenario, but bear with me.

Now imagine it's at a 45 degree angle. Neither the supports to transfer weight vertically nor those hypothetically added to give lateral support would allow it to stay in one piece in this position. Still MORE supports need to be added. Remember, the trick is to transfer the mass of the entire structure down to the ground. Doing this diagonally is extremely tricky, which is why you don't see too many tilted buildings.

So, why would these supports be needed? What possible use is a skyscraper laying on its side or tilted at a 45 degree angle? Modern skyscrapers are designed to ECONOMICALLY transfer weight vertically down to the base, which is sturdy enough to support the entire structure. The catch-22 is that the more structure is added to make the building sturdier, the more mass needs to be supported, and the more structure is needed to hold it up.

Therefore, when a skyscraper, or a portion of the skyscraper, begins to rotate beyond a certain point, it tends to fall apart. Gravity then pulls it straight down. The only way it would behave otherwise is if it were designed to hold its shape when tilted, and there's no reason to design it that way. Such a design would not save the building, and would endanger other buildings around it.

[aggle-rithm]

I think the investigators used the term "compression wave". It was essentially the compressed air pushed down the the ground and outward by the collapsing building.

This is interesting because many CT'ers deny that such a compression wave existed, because it is an alternate explanation for the "squibs" seen shooting out the sides of the towers as they collapsed.

The sight of those 'debris flows' not dispersing into the surrounding air, but 'boiling' as if a separate entity would suggest that there is more going on than compressed air blowing dust out of the way.[/quote]

I've seen a building being demolished, one much smaller than the WTC towers. I think it was about 20 stories tall.

The dust cloud it kicked up was astonishingly large, and it looked much like the ones at ground zero. From a distance it appeared to move slowly, but I'd bet that it looked just like a pyroclastic flow if you were right next to it.

Do you think this phenomenon is caused by the explosives? The reason I ask is that the cloud didn't appear when the explosives went off, but after it completed its collapse.

[Ignatz]

I remember checking the Greening paper some time ago, and if I recall the problem I had with it was that it didn't explain the total pulverisation of the topmost storeys, which gravity alone would have to account for.
Perhaps there's a fallacy there I'm not seeing that you could point out.

The fallacy is supposing that all the concrete was pulverised to dust. It wasn't. Why do you insist on retaining that requirement in every argument you make? They had jackhammers at GZ breaking up the larger pieces for removal.

[chek]

I think the investigators used the term "compression wave". It was essentially the compressed air pushed down the the ground and outward by the collapsing building.

This is interesting because many CT'ers deny that such a compression wave existed, because it is an alternate explanation for the "squibs" seen shooting out the sides of the towers as they collapsed.

The sight of those 'debris flows' not dispersing into the surrounding air, but 'boiling' as if a separate entity would suggest that there is more going on than compressed air blowing dust out of the way.

I've seen a building being demolished, one much smaller than the WTC towers. I think it was about 20 stories tall.

The dust cloud it kicked up was astonishingly large, and it looked much like the ones at ground zero. From a distance it appeared to move slowly, but I'd bet that it looked just like a pyroclastic flow if you were right next to it.

Do you think this phenomenon is caused by the explosives? The reason I ask is that the cloud didn't appear when the explosives went off, but after it completed its collapse.

As I understand it, the suspended fine particles and the heated air combine to behave as a fluid 'third element'. I'm sure the physics of the heated (and therefore less dense) air and the large volume of combined denser matter are fascinating.
In the case you witnessed the maximum amount of fine dust would be available immediately after collapse, whereas before that point, you would have mostly just energetic hot expanding gas from the explosives.
Perhaps there's a certain point at which an ideal temperature/particle availability precipitate a flow.
Have we a vulcanologist in the house?

[Ignatz]

"Then, as he reached the 22nd floor, the building shook, stairs started to heave. It sounded to Buzzelli like heavy objects were being dropped right above his head. The sound got louder, closer. He dove into a corner. “I felt the walls next to me crack and buckle on top of me,” he says. Suddenly, he seemed to be in free fall, and the walls seemed to separate and move away from him.

Maybe two hours later, he regained consciousness on a slab of concrete 180 feet below the 22nd floor. (He may be the source of the rumor that someone surfed the collapse and lived.) He was atop a hill of rubble in the midst of an endless field of rubble, smoke, and fire, sitting as if in an armchair, his feet dangling over the edge"

[chek]

I remember checking the Greening paper some time ago, and if I recall the problem I had with it was that it didn't explain the total pulverisation of the topmost storeys, which gravity alone would have to account for.
Perhaps there's a fallacy there I'm not seeing that you could point out.

The fallacy is supposing that all the concrete was pulverised to dust. It wasn't. Why do you insist on retaining that requirement in every argument you make? They had jackhammers at GZ breaking up the larger pieces for removal.

Mainly because in the immediate period after the collapse little evidence of much rubble is to be seen.
I accept that such photos may exist from later in the clean-up phase, but I can't be sure of what they are showing. They could be showing the breakup of normal rubble from the 'pulled' WTC 5 and 6 being readied for taking away.

[chipmunk stew]

I remember checking the Greening paper some time ago, and if I recall the problem I had with it was that it didn't explain the total pulverisation of the topmost storeys, which gravity alone would have to account for.
Perhaps there's a fallacy there I'm not seeing that you could point out.

The fallacy is supposing that all the concrete was pulverised to dust. It wasn't. Why do you insist on retaining that requirement in every argument you make? They had jackhammers at GZ breaking up the larger pieces for removal.

Mainly because in the immediate period after the collapse little evidence of much rubble is to be seen.
I accept that such photos may exist from later in the clean-up phase, but I can't be sure of what they are showing. They could be showing the breakup of normal rubble from the 'pulled' WTC 5 and 6 being readied for taking away.

edit: You really should contact some people involved in the clean up if you have doubts.

[aggle-rithm]

As I understand it, the suspended fine particles and the heated air combine to behave as a fluid 'third element'. I'm sure the physics of the heated (and therefore less dense) air and the large volume of combined denser matter are fascinating.
In the case you witnessed the maximum amount of fine dust would be available immediately after collapse, whereas before that point, you would have mostly just energetic hot expanding gas from the explosives.
Perhaps there's a certain point at which an ideal temperature/particle availability precipitate a flow.
Have we a vulcanologist in the house?

I'm still confused by your stance on this. Are you saying that a pyroclastic flow is typical of a controlled demolition, and therefore supports the idea that the towers were demolished, or do you think there was a fundamental difference between the WTC dust clouds and those seen when a building is demolished?

(I know there's at least one difference; at WTC the dust cloud contained toxic materials that are usually removed before a building is demolished, but that's not what I'm asking about.)

[chek]

As I understand it, the suspended fine particles and the heated air combine to behave as a fluid 'third element'. I'm sure the physics of the heated (and therefore less dense) air and the large volume of combined denser matter are fascinating.
In the case you witnessed the maximum amount of fine dust would be available immediately after collapse, whereas before that point, you would have mostly just energetic hot expanding gas from the explosives.
Perhaps there's a certain point at which an ideal temperature/particle availability precipitate a flow.
Have we a vulcanologist in the house?

I'm still confused by your stance on this. Are you saying that a pyroclastic flow is typical of a controlled demolition, and therefore supports the idea that the towers were demolished, or do you think there was a fundamental difference between the WTC dust clouds and those seen when a building is demolished?

(I know there's at least one difference; at WTC the dust cloud contained toxic materials that are usually removed before a building is demolished, but that's not what I'm asking about.)

Well, I think it looks and seems to behave very much as a classic volcanic pyroclastic flow, though of much shorter duration than would be seen naturally.
What I was attempting to get across was that other artificial conditions can likely be created, but usually endure for too short a time for much 'flow' to occur.

[chek]

The fallacy is supposing that all the concrete was pulverised to dust. It wasn't. Why do you insist on retaining that requirement in every argument you make? They had jackhammers at GZ breaking up the larger pieces for removal.

Mainly because in the immediate period after the collapse little evidence of much rubble is to be seen.
I accept that such photos may exist from later in the clean-up phase, but I can't be sure of what they are showing. They could be showing the breakup of normal rubble from the 'pulled' WTC 5 and 6 being readied for taking away.

edit: You really should contact some people involved in the clean up if you have doubts.

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Howvever I think I'm fairly safe in asserting that nowhere that a building complex has been demolished by accident or design has it left a whole city borough inches thick in powder and looking like the aftermath of Pompeii.

[Arkan_Wolfshade]

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Howvever I think I'm fairly safe in asserting that nowhere that a building complex has been demolished by accident or design has it left a whole city borough inches thick in powder and looking like the aftermath of Pompeii.

Red herring. There has never been any other building collapse, intentional or not, that involved two buildings anywhere near the magnitude of the twin towers. So, of course, things like: amount of dust, height of debris pile, etc are going to be unique.

[Ignatz]

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Except Hoffman, who pulverises every last ounce in every version of his calculations.

[chek]

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Howvever I think I'm fairly safe in asserting that nowhere that a building complex has been demolished by accident or design has it left a whole city borough inches thick in powder and looking like the aftermath of Pompeii.

Red herring. There has never been any other building collapse, intentional or not, that involved two buildings anywhere near the magnitude of the twin towers. So, of course, things like: amount of dust, height of debris pile, etc are going to be unique.

That is somewhat true in terms of both main WTC buildings added together.

A 90,000t figure for concrete per main tower was recently established, and the Seattle Kingdome contained 125,000t
http://www.controlled-demolition.com/de ... 0317140323

Nevertheless I don't recall proportionately two thirds of a similar sized area of Seattle being blanketed in concrete dust.

[chek]

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Except Hoffman, who pulverises every last ounce in every version of his calculations.

There's no getting away from the fact it was an unprecedented cloud and a mechanism for it needs to be found in the interests of understanding the whole event.
While his exploration of the answer may not be perfect in every respect, nobody else has considered its significance worth investigating.
And he is open to revision, which I interpret positively.

[Ignatz]

That is somewhat true in terms of both main WTC buildings added together.

A 90,000t figure for concrete per main tower was recently established, and the Seattle Kingdome contained 125,000t
http://www.controlled-demolition.com/de ... 0317140323

Nevertheless I don't recall proportionately two thirds of a similar sized area of Seattle being blanketed in concrete dust.

Was that mostly reinforced structural concrete?

How far did it fall?

Was it encountering 300m of massive steel core on the way down?

Was the concrete falling onto 70 or 80 more layers of lightweight concrete??

Was it lined with plasterboard?

Had they removed the lagging, insulation and asbestos?

Have you lost all sense of intellectual honesty?

[chek]

That is somewhat true in terms of both main WTC buildings added together.

A 90,000t figure for concrete per main tower was recently established, and the Seattle Kingdome contained 125,000t
http://www.controlled-demolition.com/de ... 0317140323

Nevertheless I don't recall proportionately two thirds of a similar sized area of Seattle being blanketed in concrete dust.

Was that mostly reinforced structural concrete?

How far did it fall?

Was it encountering 300m of massive steel core on the way down?

Was the concrete falling onto 70 or 80 more layers of lightweight concrete??

Was it lined with plasterboard?

Had they removed the lagging, insulation and asbestos?

Have you lost all sense of intellectual honesty?

I understood the comparison to mean has a similar mass of concrete been blown up before - as arkan pointed out, there are no parallels to the WTC demolition anywhere, anytime.
I can see the problem if you are maintaining that gravity alone was responsible for the pulverisation.

[chipmunk stew]

I know this is getting repetetive, but as far as I am aware, nobody has claimed that every single scrap of concrete was powderised.

Howvever I think I'm fairly safe in asserting that nowhere that a building complex has been demolished by accident or design has it left a whole city borough inches thick in powder and looking like the aftermath of Pompeii.

Red herring. There has never been any other building collapse, intentional or not, that involved two buildings anywhere near the magnitude of the twin towers. So, of course, things like: amount of dust, height of debris pile, etc are going to be unique.

That is somewhat true in terms of both main WTC buildings added together.

A 90,000t figure for concrete per main tower was recently established, and the Seattle Kingdome contained 125,000t
http://www.controlled-demolition.com/de ... 0317140323

Nevertheless I don't recall proportionately two thirds of a similar sized area of Seattle being blanketed in concrete dust.

That's because it was a CONTROLLED demolition. Very much UNLIKE the WTC. They removed much of the dust-producing material and introduced measures to contain the dust and debris.

[aggle-rithm]

Well, I think it looks and seems to behave very much as a classic volcanic pyroclastic flow, though of much shorter duration than would be seen naturally.
What I was attempting to get across was that other artificial conditions can likely be created, but usually endure for too short a time for much 'flow' to occur.

Thanks, but I'm still confused about your stance on the whole 'pyroclastic flow' issue. Are you saying that a pyroclastic flow is typical of a controlled demolition, and therefore supports the idea that the towers were demolished, or do you think there was a fundamental difference between the WTC dust clouds and those seen when a building is demolished?

[chek]

Well, I think it looks and seems to behave very much as a classic volcanic pyroclastic flow, though of much shorter duration than would be seen naturally.
What I was attempting to get across was that other artificial conditions can likely be created, but usually endure for too short a time for much 'flow' to occur.

Thanks, but I'm still confused about your stance on the whole 'pyroclastic flow' issue. Are you saying that a pyroclastic flow is typical of a controlled demolition, and therefore supports the idea that the towers were demolished, or do you think there was a fundamental difference between the WTC dust clouds and those seen when a building is demolished?

I really unable to answer your question any further than I already have.
Studying CD's is not a passtime of mine, and I can only reiterate that the WTC dust cloud looked uncannily like the flows I've seen during volcanic eruptions. How typical that is I'm unable to say.

[chipmunk stew]

Well, I think it looks and seems to behave very much as a classic volcanic pyroclastic flow, though of much shorter duration than would be seen naturally.
What I was attempting to get across was that other artificial conditions can likely be created, but usually endure for too short a time for much 'flow' to occur.

Thanks, but I'm still confused about your stance on the whole 'pyroclastic flow' issue. Are you saying that a pyroclastic flow is typical of a controlled demolition, and therefore supports the idea that the towers were demolished, or do you think there was a fundamental difference between the WTC dust clouds and those seen when a building is demolished?

I really unable to answer your question any further than I already have.
Studying CD's is not a passtime of mine, and I can only reiterate that the WTC dust cloud looked uncannily like the flows I've seen during volcanic eruptions. How typical that is I'm unable to say.

Is studying volcanic eruptions a passtime [sic] of yours?
If you can't be sure that pyroclastic flow is indicative of a CD, on what basis do you argue that a pyroclastic flow in evidence that WTC was a CD? Shouldn't you be arguing it as evidence that it was a volcanic eruption?