9-11/WTC question

This isn't his answer for your question, but I'll quote what he said before. He's a firefighter.

 

sorry, debris doesn't just shoot outward, as if propelled, from simply collapsing.

and jet fuel doesn't combust at a temperature high enough to cause a total collapse of the steel framework; they were built to withstand hours of sustained heat at high temperature.
http://911review.com/attack/wtc/fires.html (I already posted this too)

"one of the first people to point out the absurdity of the idea that building fires with hydrocarbon fuels could melt steel was J.McMichael..."

your expert buddy's explanation doesn't prove how fire caused a total breakdown of the building's integrity

 

Where do you want the debris to go, make a sand tower or tube or whatever, and pushit it down very fast and hard, it will shoot outwards.

You need to read it again, he does explain how. Here is another post because another person basicaly said that same thing you did.

EDIT: damn you edited.

 

those steel beams are not going to give way in a few minutes of burning from a simple hydrocarbon fire, sorry (I know that, and I'm not even a firefighter, I'm a chemist); thermite maybe, but not jet fuel.

 

Hours?

 

(note the melting point of iron) a few minutes of fire isn't enough to cause each building to collapse, that's just utter bullshit

http://www.911review.com/articles/jm/mslp_1.htm

"Using jet fuel to melt steel is an amazing discovery, really. It is also amazing that until now, no one had been able to get it to work, and that proves the terrorists were not stupid people. Ironworkers fool with acetylene torches, bottled oxygen, electric arcs from generators, electric furnaces, and other elaborate tricks, but what did these brilliant terrorists use? Jet fuel, costing maybe 80 cents a gallon on the open market.

Let us consider: One plane full of jet fuel hit the north tower at 8:45 a.m., and the fuel fire burned for a while with bright flames and black smoke. We can see pictures of white smoke and flames shooting from the windows.

Then by 9:03 a.m. (which time was marked by the second plane's collision with the south tower), the flame was mostly gone and only black smoke continued to pour from the building. To my simple mind, that would indicate that the first fire had died down, but something was still burning inefficiently, leaving soot (carbon) in the smoke. A fire with sooty smoke is either low temperature or starved for oxygen — or both.

But by 10:29 a.m., the fire in north tower had accomplished the feat that I find so amazing: It melted the steel supports in the building, causing a chain reaction within the structure that brought the building to the ground.

And with less fuel to feed the fire, the south tower collapsed only 47 minutes after the plane collision, again with complete destruction. This is only half the time it took to destroy the north tower.

I try not to think about that. I try not to think about a petroleum fire burning for 104 minutes, just getting hotter and hotter until it reached 1538 degrees Celsius (2800 Fahrenheit) and melted the steel (steel is about 99% iron; for melting points of iron and steel see http://www.webelements.com/webelements/elements/text/Fe/heat.html, http://www.weldtechnology.com/rwintroduction.html or http://www.911review.com/articles/jm/cache/rwintro.html).

(Celsius/Fahrenheit conversion tool at http://www.vaxxine.com/mgdsite/celcon.htm.)

I try not to wonder how the fire reached temperatures that only bottled oxygen or forced air can produce.

And I try not to think about all the steel that was in that building — 200,000 tons of it (for WTC statistics see http://www.infoplease.com/spot/wtc1.html or http://www.911review.com/articles/jm/cache/wtc_hist.html).

I try to forget that heating steel is like pouring syrup onto a plate: you can't get it to stack up. The heat just flows out to the colder parts of the steel, cooling off the part you are trying to warm up. If you pour it on hard enough and fast enough, you can get the syrup to stack up a little bit. And with very high heat brought on very fast, you can heat up one part of a steel object, but the heat will quickly spread out and the hot part will cool off soon after you stop.

Am I to believe that the fire burned for 104 minutes in the north tower, gradually heating the 200,000 tons of steel supports like a blacksmith's forge, with the heat flowing throughout the skeleton of the tower? If the collapse was due to heated steel, the experts should be able to tell us how many thousands of tons of steel were heated to melting temperature in 104 minutes and how much fuel would be required to produce that much heat. Can a single Boeing 767 carry that much fuel?

Thankfully, I found this note on the BBC web page
( http://news.bbc.co.uk/hi/english/world/americas/newsid_1540000/1540044.stm or http://www.911review.com/articles/jm/cache/BBCNews_wtcfell.html): "Fire reaches 800 [degrees] C — hot enough to melt steel floor supports."

That is one of the things I warned you about: In the 20th Century, steel melted at 1535 degrees Celsius (2795 F) (see http://www.chemicalelements.com/elements/fe.html), but in the 21st Century, it melts at 800 degrees C (1472 F).

This might be explained as a reporter's mistake — 800 to 900 C is the temperature for forging wrought iron. As soft as wrought iron is, of course, it would never be used for structural steel in a landmark skyscraper. (Descriptions of cast iron, wrought iron, steel, and relevant temperatures discussed at http://www.metrum.org/measures/castiron.htm or http://911review.com/articles/jm/cache/castiron.htm.)

But then lower down, the BBC page repeats the 800 C number in bold, and the article emphasizes that the information comes from Chris Wise, "Structural Engineer." Would this professional individual permit himself to be misquoted in a global publication?

Eduardo Kausel, an M.I.T. professor of civil and environmental engineering, spoke as follows to a panel of Boston area civil and structural engineers: "I believe that the intense heat softened or melted the structural elements — floor trusses and columns — so that they became like chewing gum, and that was enough to trigger the collapse." Kausel is apparently satisfied that a kerosene fire could melt steel — though he does not venture a specific temperature for the fire ( http://www.911review.com/articles/jm/cache/sciam_whenfell.html).

I feel it coming on again — that horrible cynicism that causes me to doubt the word of the major anchor-persons. Please just think of this essay as a plea for help, and do NOT let it interfere with your own righteous faith. The collapse of America's faith in its leaders must not become another casualty on America's skyline.

In my diseased mind, I think of the floors of each tower like a stack of LP (33-1/3 RPM) records, except that the floors were square instead of circular. They were stacked around a central spindle that consisted of multiple steel columns interspersed with dozens of elevator shafts (see http://www.skyscraper.org/tallest/t_wtc.htm, http://www.civil.usyd.edu.au/wtc.htm and http://www.GreatBuildings.com/buildings/World_Trade_Center.html).

 

It talk about melting and softening, what about expansion?
What do you mean by few minutes? Material was burning after the jet fuel has completly combusted.

 

source, pls.

was that combustible material enough to cause substantial enough heat to expand the steel girders, resulting in collapse in just 45 mins? any proof?


45 minutes was how long the first building was burning; the steel framework was built to withstand hours of burning. jet fuel combustion alone (even at 2000º for 45 mins) wouldn't cause the building to collapse in that short amount of time.

I don't buy it, and neither would any other sensible person.

 

http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html here I found this, a nice explenation of everything.

And to answer your specific question: " This is why the temperatures in a residential fire are usually in the 500°C to 650°C range.2,3 It is known that the WTC fire was a fuel-rich, diffuse flame as evidenced by the copious black smoke. Soot is generated by incompletely burned fuel; hence, the WTC fire was fuel rich—hardly surprising with 90,000 L of jet fuel available. Factors such as flame volume and quantity of soot decrease the radiative heat loss in the fire, moving the temperature closer to the maximum of 1,000°C. However, it is highly unlikely that the steel at the WTC experienced temperatures above the 750–800°C range. All reports that the steel melted at 1,500°C are using imprecise terminology at best"

"It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C"

Edit: your edits....

 

http://www.whatreallyhappened.com/wtc_fire.html

"The "truss theory" relies on the assumption that 800ºC+ infernos started a catastrophic chain of events which led to the collapse of the twin towers. There were fires in both buildings following the aircraft impacts, but no infernos - "most perimeter panels (157 of 160) saw no temperatures above 250ºC."


could speculate all day, for several days, how hot the flames got in there, but specific heat capacities are constant; and jet fuel combustion alone wasn't enough to cause expansing, then buckling, as much as agencies and contractors would like you to believe. 45 mins, and poof? right...

 

looking for other sites on the matter too, and found this one http://vincentdunn.com/wtc.html

but he erroneously said

"Unfortunately unprotected steel warps, melts, sags and collapses when heated to normal fire temperatures about 1100 to 1200 degrees F."

steel doesn't melt anywhere in that range, under normal atmospheric conditions; and the "truss theory" is refuted in my previous link.

just to clear things up (and pardon me if I worded it incorrectly): I'm not disputing what caused the collapse, they collapsed under the weight of the buildings...structural integrity was compromised; what caused that compromise is what I'm skeptical about.

anywho, we're digressing; "shit happens" ... why did this shit happen?

 

No tempetures above 250C? A class A fire burns hotter than that...
Concrete, I think that we both know that concrete wouldn't do anything to stop the steel's expansion because it is designed to support vertical pressure and not horizontal.

The link I provided does explain the cause of the compromise of structural integrity. You're better off reading all of it but I'll quote a part of it.

"It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C.4 This is why steel is stress relieved in this temperature range. But even a 50% loss of strength is still insufficient, by itself, to explain the WTC collapse. It was noted above that the wind load controlled the design allowables. The WTC, on this low-wind day, was likely not stressed more than a third of the design allowable, which is roughly one-fifth of the yield strength of the steel. Even with its strength halved, the steel could still support two to three times the stresses imposed by a 650°C fire.

The additional problem was distortion of the steel in the fire. The temperature of the fire was not uniform everywhere, and the temperature on the outside of the box columns was clearly lower than on the side facing the fire. The temperature along the 18 m long joists was certainly not uniform. Given the thermal expansion of steel, a 150°C temperature difference from one location to another will produce yield-level residual stresses. This produced distortions in the slender structural steel, which resulted in buckling failures. Thus, the failure of the steel was due to two factors: loss of strength due to the temperature of the fire, and loss of structural integrity due to distortion of the steel from the non-uniform temperatures in the fire."

 

http://www.911review.com/articles/jm/mslp_2.htm

"Note that structural steel at 550 degrees C (1022 F) has 60% of the strength of steel at normal temperatures. This weakening of steel when heated is supposedly responsible for the catastrophic collapse of the towers. The statement generates three questions to be answered in order to determine whether this phenomenon could cause the collapse of the World Trade Center:

1. How much strength would the steel have to lose for the WTC to collapse?

2. What temperature would the steel have to reach to occasion this loss of strength?

3. What was the temperature of the fire in the WTC; i.e., did it reach the critically weakening temperature?
Question 1:

In the original article, I cited my own experience that a support device must be capable of bearing three times the maximum load that would ever be applied.

It turns out that this rule-of-thumb is applicable only to dynamic loads, not static (structural) loads of commercial buildings. Since then, I have been informed by a commercial structural engineer that the standard ratio for static loads is five, not three. That is, if a bridge is rated to carry 1 ton, it should be capable of bearing 5 tons without collapsing at the time the bridge is built.

Going back to the fire at the WTC, we can see that reducing the steel structure to 60% its rated strength should NOT have weakened it to catastrophic collapse, because at 60% it would still support three times the rated load. The steel structure would have to be reduced to 20% of its rated strength to collapse.

Thus, even if the fire had heated the steel to 550 degrees C (1022 F), that would not have been sufficient to cause the towers to collapse.
Question 2:

The Corus page on fire vs. steel supports (http://www.corusconstruction.com/fire/fr006.htm mirrored at http://www.911review.com/articles/jm/cache/fr006.html ) shows that the steel would have to be heated to about 720 degrees C (1320 F) to weaken the steel to 20% of its cool strength.

The text on that page discusses another change in the steel above 550 degrees C (1022 F): It looses elasticity and becomes plastic. Elasticity means that when the steel is bent, it returns to its original shape; it springs back. Plasticity means that the steel is permanently deformed and does not spring back to the original shape.

Springing back or not, our only concern with this page is to determine the point on the graph where the steel would be weakened to 20% its original strength, and that point is 720 degrees C (1320 F).

For steel, 550 degrees C (1022 F) is an important threshold, however, and we should not be glib with it. If a steel tower were heated to 550 C, loss of elasticity could mean that the tower would not spring back to the original shape after a gust of wind, and a series of buffets might cause the tower to fail -- if the strain exceeded the reduced strength of the hot steel.
Question 3:

Now let us make a guess on the actual heat of the fire.

Fortunately, a number of studies have been done under very similar conditions. In Europe, multi-storied "car parks" are often built of steel, and the possibility of vehicle fire is a distinct possibility. A parked vehicle, loaded with gasoline, diesel, tires, engine oil, engine tar, upholstery, hydraulic fluid, etc. can cause a fire that seems very hot. A number of other vehicles could be parked close to the burning one, and they too could catch fire, with a general conflagration. Any number of cars could contain almost any household items from shopping, etc.

These materials are similar to the materials we would expect in the burning offices of the WTC: jet fuel (which is a refined kerosene, very similar to the diesel used in some European cars), oil, upholstery, etc.

A summary of the results of these studies is published on the Corus page. Go to http://www.corusconstruction.com/ and click on "Fire". Individual articles are listed across the top of the window. The fourth article, "Fire in Car Parks," discusses the temperatures of "any fires that are likely to occur" in a car park ( http://www.corusconstruction.com/carparks/cp006.htm mirrored at http://www.911review.com/articles/jm/cache/cp006.htm ).

Presumably, one car could catch fire and inflame other cars parked closely nearby. As explained below, "The maximum temperatures reached [in actual test fires] in open sided car parks in four countries" was 360 degrees C (680 F), and structural steel has "sufficient inherent resistance to withstand the effects of any fires that are likely to occur."

Here is the relevant paragraph, complete: "Steel-framed car parks have been rigorously fire tested in a number of countries (Table 3). These tests demonstrate that most unprotected steel in open sided steel-framed car parks has sufficient inherent resistance to withstand the effects of any fires that are likely to occur. Table 3 lists the maximum temperatures reached in open sided car park tests in four countries. These can be compared with the characteristic failure temperatures for beams carrying insulating floor slabs and columns of 620 [degrees] C and 550 [degrees] C respectively."

Note that the description does not limit the duration of the fire. From this it does not appear to matter whether the fire burned all week or just for two hours. No mention is made, as some people have suggested (from erroneous interpretation of other graphs involving time), that prolonged heat brings about progressive weakening of steel.

Here is the data from Corus' Table 3 (beams are horizontal members, columns are vertical):
Full scale fire tests Maximum measured steel temperature
Country Beam Column
UK 275 C (527 F) 360 C (680 F)
Japan 245 C (473 F) 242 C (467 F)
USA 226 C (438 F) -
Australia 340 C (644 F) 320 C (608 F)

A fire in a steel car park is a very imprecise event, and the heating of the steel supports varied widely in the tests. The temperature of (horizontal) beams varied from 226 C in the USA to 340 C in Australia; and the temperature of (vertical) columns varied from 242 C in Japan to 360 C in the UK. None of the steel was protected with the thermal insulation that is commonly used in office buildings, including the WTC.

To my mind, this is definitive answer: the maximum temperature in the unprotected steel supports in those test fires was 360 degrees C (680 F), and that is a long way from the first critical threshold in structural steel, 550 degrees C (1022 F).

Some may argue that there was much more fuel involved in the WTC events that in a car park. There was also much more steel involved, the support columns were more massive, and they were protected with insulation.

I think the case is made: The fire did not weaken the WTC structure sufficiently to cause the collapse of the towers."

 

"...Both of the above buildings were of inferior build quality to the WTC, yet they burned hotter & far longer than the twin towers & WTC 7 AND REMAINED STANDING."

from http://www.whatreallyhappened.com/wtc_fire.html

 

Hmmm we have 2 different kinds of information and tempetures, so you will have too look at credibility, according to my website these are his references:
References

1. Presentation on WTC Collapse, Civil Engineering Department, MIT, Cambridge, MA (October 3, 2001).
2. D. Drysdale, An Introduction to Fire Dynamics (New York: Wiley Interscience, 1985), pp. 134–140.
3. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 10–67.
4. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 6-62 to 6-70.
5. Steven Ashley, “When the Twin Towers Fell,” Scientific American Online (October 9, 2001); www.sciam.com/explorations/2001/100901wtc/
6. Zdenek P. Bazant and Yong Zhou, “Why Did the World Trade Center Collapse?—Simple Analysis,” J. Engineering Mechanics ASCE, (September 28, 2001), also www.tam.uiuc.edu/news/200109wtc/
7. Timothy Wilkinson, “World Trade Centre–New York—Some Engineering Aspects” (October 25, 2001), Univ. Sydney, Department of Civil Engineering; www.civil.usyd.edu.au/wtc.htm.
8. G. Charles Clifton, “Collapse of the World Trade Centers,” CAD Headlines, tenlinks.com (October 8, 2001); www.tenlinks.com/NEWS/special/wtc/clifton/p1.htm.

Thomas W. Eagar, the Thomas Lord Professor of Materials Engineering and Engineering Systems, and Christopher Musso, graduate research student, are at the Massachusetts Institute of Technology.

The data from my link seems a lot more true than something that comes from a free thinker. And also a firefighter supported what I said about the tempetures.

Also in WTC there was a lot more heat transfered into steel than in those cars.

From personal experience, just from burning wood for an hour in my fireplace, the steel (I think) on the top became red (and of course that is not good so I lowered the oxygen).

The tempeture was also not uniform in the WTC. Also the claims that the structure could hold 3 times it's weight...we had an impact and an explosion, destroying steel parts too. The way a steel-structure is designed is each floor ONLY has to support itself, and NOT THE FLOOR ABOVE IT. Re-read that, since its very important.
The weight of the floors above are passed down the super-structure, and NOT THROUGH THE FLOORS BENEATH.

 

Yes that makes me skeptical too, I need an answer for that too, it might be because there was no firefighting in WTC7.

 

yes, I am well aware that each floor is only designed to hold its own weight; what doesn't match is the thermodynamic effects and the tensile strength of the beams from the WTC, none of your links address that; free-thinking isn't the issue (despite the fact that you posted a lot of contracted investigation links)

what caused the collapse isn't the issue (weight caused it); what's the issue is "what caused the steel beams to give", you haven't proved that, nor has your firefighter expert witness; lots of numbers tossed around (1500, 2000, 650C, non-uniform burning), but nothing has been proven; a mechanical engineering paper with theoretical values doesn't constitute proof.

 

there was a fire in a high rise Puerto Rico hotel back in 1986, that also burned hotter, for about 20 hours before it collapsed.

 

Hmm well they say that the steel did get weakened, by a lot, and warped.
Steel from WTC7:

Notice how warped it is, from heat.

"The perimeter tube design of the WTC was highly redundant. It survived the loss of several exterior columns due to aircraft impact, but the ensuing fire led to other steel failures. Many structural engineers believe that the weak points—the limiting factors on design allowables—were the angle clips that held the floor joists between the columns on the perimeter wall and the core structure (see Figure 5). With a 700 Pa floor design allowable, each floor should have been able to support approximately 1,300 t beyond its own weight. The total weight of each tower was about 500,000 t. "


And thermo-dynamics, last time you addressed that was for the fact that the top part collapsed downwards and not latteraly.

"It has been suggested that it was fortunate that the WTC did not tip over onto other buildings surrounding the area. There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down. "

 

The building collapsed? Well what's up with loose change saying that WTC is the first building to collapse because of fire?