The Cardington fire tests
This post is in response to the 1st part of shaman_'s
post 1020 from this thread.
scott3x said:
From what I remember, Headspin said that the Cardington fire tests were done to see what happened to steel at varying temperatures, not to simulate what the WTC office fires were like.
Irrelevant.
I don't think so.
You are trying to dodge a key point. The last test was done using office furniture and the temperature was near 1000C.
You seem to think that all office buildings are alike. They aren't. Size really -does- matter.
NIST's own workstation fire tests reached temperatures near, and over 1000C.
NIST's computer models are a joke to many. When it comes to all their tests of -real- steel as opposed to their tweaked computer models, they haven't reported -any- steel beams to collapse. Not even on a model that Tony claims had no fireproofing at all.
There have been several other fires where the steel collapsed.
Yes, steel warehouses and the like; very weak structures indeed.
You never looked at the link Kenny provided and it has been given to you four times. Regular fires can reach temperatures hot enough to weaken steel.
I never denied this. The problem you're making is that you seem to think that the weak framework of a steel warehouse is the same thing as the massive framework of the WTC buildings.
shaman_ said:
scott3x said:
Tests -were- done to simulate what the WTC office fires were like; well, not quite, as they were put under more stress then the WTC office fires would have normally taken. Nevertheless, while the steel beams did sag a bit (I believe it was 3 inches), they certainly didn't sag the 40 inches as in the NIST report and even though they steel beams used were half the size of the WTC ones, it wouldn't mean that it would go from 3 inches to 40.
You are referring to tests done on components with fireproofing intact.
In one of the tests that I have mentioned in the past, Kevin Ryan claims that there was essentially no fireproofing.
shaman_ said:
In these test you mention, which were done to simulate office fires, what temperatures were reached?
I'm not sure, but it's irrelevant. They reached temperatures that are consistent with the -real- fires, not NIST's tweaked out computer simulations. As a matter of fact, they biased the tests, as Kevin Ryan explained in a letter on the 9/11 Journal for 9/11 Studies,
The Short Reign of Ryan Mackey, and yet the floor models still didn't fail:
Not only did UL and NIST add twice as much add twice the known WTC load to the floor models, they also used far less fireproofing than was known to exist at the time. The tests performed by UL included two test specimens with "as built" fireproofing of only 0.75 inches, one with the "as specified" fireproofing thickness of only 0.5 inches, and one with the "as specified" condition of essentially no fireproofing. None of the test specimens had fireproofing to represent the "as impacted" condition of 3.25 inches, reported in NCSTAR 1-6A, figure A-60.
shaman_ said:
scott3x said:
Splendid. The WTC office fires couldn't have reached 1000C unaided for more then a few seconds, however, in what is called 'flashover', unless they got significant help from certain incendiaries/explosives.
Your response is nothing more than a baseless assertion. Read it for yourself. Now that you have learnt the term flashover you are throwing it around as if simply using it carries weight.
My assertion isn't baseless. It is based on information from Jim Hoffman's
Building a Better Mirage article, which is a "critique of the Final Report of the National Construction Safety Team on the Collapses of the World Trade Center Towers
by the Federal Building and Fire Safety Investigation of the World Trade Center Disaster."
Here is what he said in the section titled "Imagined Heat":
Temperatures of 800 ºC to 1,100 ºC (1472 ºF to 2012 ºF) are normally observed only for brief times in building fires, in a phenomenon known as flashover. Flashover occurs when uncombusted gases accumulate near the ceilings and then suddenly ignite. Since flame consumes the pre-heated fuel-air mixture in an instant, very high temperatures are produced for a few seconds.
Scott, there is a very simple point to be made here. If the fires couldn't reach temperatures high enough to weaken steel then why was the steel fireproofed?
When did I say that the fires couldn't reach temperatures high enough to weaken steel? It's one thing to weaken steel, however- it's another thing entirely for the WTC buildings to complete collapse within seconds of collapse initiation.
shaman_ said:
scott3x said:
Actually, it does. You see, steel has this property called conductivity
The steel in the Cardington tests did not conduct very well between two connected pieces. There were significant differences in temperature.
The Cardington tests were not simulating the floor models of the WTC buildings. UL and NIST -did- simulate the floor models of the WTC buildings, albeit doubling the load and decreasing the 'as impacted' fireproofing. Nevertheless, although the floor models did sag somewhat, they did -not- collapse. Jim Hoffman, in his article,
Maintaining the Mirage: A Foray Into the Fallacy Factory of the Demolition Deniers, states:
Mackey cites the Cardington experiments to support his claim that that the hydrocarbon-fueled fires can sustain temperatures exceeding 1000°C, but it doesn't follow that such temperatures are typically reached in actual building fires. The Cardington experiments, like other such fire tests, were designed to see how structures behave in hot fires -- at the high end of temperatures that the scientists think might be reached in a building fire, not the likely temperatures.
And, despite the fact that the Cardington tests heated steel to temperatures hundreds of degrees hotter than any temperatures NIST claims to have estimated from studies of WTC structural steel samples, no collapse was observed in any of the experiments.
shaman_ said:
scott3x said:
and your idea that the office fires could have reached 1000C isn't supported by the evidence.
I’m showing you evidence that it most certainly could have. You are doing everything you can to avoid accepting this evidence.
All you've shown me is that the -Cardington fire tests- reached those temperatures. You have shown me no compelling evidence that the same occurred in relation to the WTC buildings.
shaman_ said:
scott3x said:
And if the office fires didn't reach 1000C, then conductivity is definitely a factor.
What point are you making here?
1000C is not surprising at all a temperature for an office fire to reach, particularly if it has been helped along with an explosion of a few thousand gallons of jet fuel and then the rest splashed around.
-That- is an assertion you haven't provided any evidence for as far as I can tell. Jim Hoffman certainly doesn't agree with it. The open air burning temperature of jet fuel is
287.5 °C (549.5 °F). That's a far cry from 1000 °C.
shaman_ said:
scott3x said:
shaman_ said:
scott3x said:
Ah, so if the core collapses then the problem -must- be poor design? As it happens, the WTC buildings had steel frames- no concrete to be found in them. It was the -Madrid- tower that had the concrete frames. They were weakly reinforced with steel, but as I make clear below, the reinforcement was weak and the load bearing was mainly done by the core.
That paragraph is gibberish...
Actually, it's not, but I can certainly believe that you don't understand it.
Isn’t that comment a little insulting for you?
Perhaps.. from me. From you, I'd consider it to be fairly civil ;-). If I had been in a better mood, perhaps I would have asked you what you didn't understand.
No, that paragraph is unclear scott.
What don't you understand in the paragraph?
The key difference is that the Madrid tower had a concrete core while the WTC had a steel inner tube.
The WTC towers had a tube within a tube design; I got that bit from 9/11 Research. But the point is that the reason the Madrid tower's upper perimeter collapsed was because the perimeter was made from weakly reinforced concrete, not the strong perimeter steel columns that the WTC buildings had.
Your interpretation about ‘poor design’ is baffling. You claim that the reinforcement was weak but refuse to accept that the weakness here is that steel is more susceptible to fire
You have it backwards. Concrete is susceptible to spalling. Steel isn't. Not only that, but steel -hardens- after being bent to some degree, as Tony has mentioned in the past. Also, steel conducts heat much better then concrete, so that the hottest parts quickly lose their heat unless the temperature gets -really- hot. For these reasons, steel is much better at resisting the destructive force of fire.
and say the load bearing was done by the (concrete!) core. What point are you making?
The core of the Windsor tower was meant to take the majority of the load; in other words, it was much heftier then the poorly reinforced concrete perimeter.