The Twin Towers at free fall speed

[aggle-rithm]

It's not that the measure of energy release is more relevant or more easily testable. It's another way to measure energy and heat but it's not necessarily a more accurate way to assess the situation in the towers.

In all the fine detail they go into about the uncertainty the various types of thermocouples introduce, the way the hydrocarbon fuel was mixed and dispersed, the position of the steel members to the flame, etc., they couldn't or didn't put some ambient thermometers to calculate the gas temperatures?

You may feel the urge to accuse me of nitpicking the test "to my standards" but don't you think that the gas temperature would be a useful bit of information in a test of this sort? And while they're going through the laborious task of building the structures and configuring the tests, why in the world would they choose NOT to measure the gas temps?

A skeptic would say something like, "the testers probably DID measure the gas temps, but that info was left out because either:

1. gas temps added no new info
2. they forgot
3. the test designers did not specifically call for a measure of gas temps
or
They really didn't measure the gas temps because...?

Worst-case scenario for supporters of the official CT is that the test designers are guilty of poor test design. Most will shrug this measurement off as "unnecessary," adding something about heat and temp and tacking on a circumstantial ad hom about my ignorance.

Doesn't change the facts about this scenario: there is no clear theory being tested about the temperatures the steel needed to get to in order to exhibit the theorized failure modes.

Steel structures are not rated against a "heat-release rate," they are rated against temperature and time. Why is that not a good standard to test the structures?



.

Please regale us with a theory that you feel fits the evidence better.

 

[jay howard]

I think that you don't fully understand the difference between temperature & heat.

Heat release is the proper consideration here.

Is that because of the application of the results or because of the form their theory takes?

Nothing "called for parts to get to 600C". In any time frame.

Yes, it did. Read the test specs at the beginning of chapter 9, 1-5B.

The temperature of the steel in the towers did not need to get anywhere close to 600° in order for the towers to collapse. At the stress levels that they saw from the physical damage, the creep that ultimately initiated the collapse would be expected at temperature in the 300°C range.

Did you get this from the NIST report? I'd really like to see where it says that.

The steel temperatures in WTC7 that led to its collapse were also never anywhere close to 600°C. If you read the report carefully, you will see this described in detail.

This is real far from supporting a heat-induced collapse mechanism for WTC 7.



.

 

[jay howard]

Others have stated that hydrocarbon fires cannot acheive 1000F. However in Canada at least, fire codes specify a chimney that can withstand an internal temp of 2100F

The ULC code specifies:
Max Continuous 650°C (1200°F)
Brief Forced Firing 925°C (1700°F)
Tested To 1150°C (2100°F)

Hmmm, I wonder why?

That's like judging how fast a car is by looking at the speedometer. Hydrocarbon fires in a naturally-aspirated environment can get to approximately 1100C--NOT 1100F. Big difference.

The burn proxy tests reported on by NIST saw temp spikes of about 1000C for 5 to 10 minutes. Most of the time they were at or below 500C.


.

 

[Newtons Bit]

It's not that the measure of energy release is more relevant or more easily testable. It's another way to measure energy and heat but it's not necessarily a more accurate way to assess the situation in the towers.

In all the fine detail they go into about the uncertainty the various types of thermocouples introduce, the way the hydrocarbon fuel was mixed and dispersed, the position of the steel members to the flame, etc., they couldn't or didn't put some ambient thermometers to calculate the gas temperatures?

You may feel the urge to accuse me of nitpicking the test "to my standards" but don't you think that the gas temperature would be a useful bit of information in a test of this sort? And while they're going through the laborious task of building the structures and configuring the tests, why in the world would they choose NOT to measure the gas temps?

A skeptic would say something like, "the testers probably DID measure the gas temps, but that info was left out because either:

1. gas temps added no new info
2. they forgot
3. the test designers did not specifically call for a measure of gas temps
or
They really didn't measure the gas temps because...?

Worst-case scenario for supporters of the official CT is that the test designers are guilty of poor test design. Most will shrug this measurement off as "unnecessary," adding something about heat and temp and tacking on a circumstantial ad hom about my ignorance.

Doesn't change the facts about this scenario: there is no clear theory being tested about the temperatures the steel needed to get to in order to exhibit the theorized failure modes.

Steel structures are not rated against a "heat-release rate," they are rated against temperature and time. Why is that not a good standard to test the structures?



Yea, that's me again. Thanks.


.

The contents of the WTC fire did not release temperature, they released energy. Trying to measure the temperature release is nonsensical.

Furthermore, the air temp in the tests can be inferred from the surface temperature of the materials. I'd have to read through the report again to see if they actually measured the gas temperature itself, but quite frankly: it's really not important or relevant.

 

[TruthersLie]

Is that because of the application of the results or because of the form their theory takes?
<snip>
.

Ah yes...

educate a structural engineer... feel free to tell him how he is wrong.

Like I have said before, where is your thesis? Which journal has published the FIRST truther paper refuting any part of NIST?

Which journal is that again?

And it is nit picking...which still doesn't change the fact that 19 terrorists hijacked 4 jets and crashed 3 into buildings.

 

[jaydeehess]

That's like judging how fast a car is by looking at the speedometer.

No, a car's speedometer can have any upper limit one wanbts to put on it with no verification required that the vehicle could ever reach that. the chimney standards are there to allow a one time chimney fire to occur without causing a fire to the structure. If you have had a chimney fire then the chimney is no longer assumed to be able to still meet the standard and should be replaced. What does that say about the temps reached jay? That its all just a make-believe.

Hydrocarbon fires in a naturally-aspirated environment can get to approximately 1100C--NOT 1100F. Big difference.

A chimney fire creates its own forced draft.

The burn proxy tests reported on by NIST saw temp spikes of about 1000C for 5 to 10 minutes. Most of the time they were at or below 500C.


.

,and at 500C a steel structural member that is already experiencing loads it was not normally designed to withstand it may well fail.

 

[sylvan8798]

That's like judging how fast a car is by looking at the speedometer. Hydrocarbon fires in a naturally-aspirated environment can get to approximately 1100C--NOT 1100F. Big difference.

The burn proxy tests reported on by NIST saw temp spikes of about 1000C for 5 to 10 minutes. Most of the time they were at or below 500C.


.

1100 C is 2012F. What are you trying to say here?

 

[Sword_Of_Truth]

Others have stated that hydrocarbon fires cannot acheive 1000F. However in Canada at least, fire codes specify a chimney that can withstand an internal temp of 2100F

I've been told by members of the local fire department (Edmonton, Alberta) that common household fires can reach 1700F.

 

[Furcifer]

A chimney fire creates its own forced draft.

I think you meant to say natural draft. Forced or induced draft usually come as a result of a fan or blower. I suppose chimney effect could be considered a "naturally induced" draft but I haven't heard it used like that.

 

[alienentity]

That's like judging how fast a car is by looking at the speedometer. Hydrocarbon fires in a naturally-aspirated environment can get to approximately 1100C--NOT 1100F. Big difference.

The burn proxy tests reported on by NIST saw temp spikes of about 1000C for 5 to 10 minutes. Most of the time they were at or below 500C.

Err, that's a couple thousand degrees Farenheit. That's mighty hot, lad.

Are you familiar with viscoplastic buckling? Look it up. Depending on the load experienced, steel will fail at temps below 500C.....way below that actually.

Since the planes damaged lots of columns in both towers, the loads experienced by the remaining structure were significantly greater than their original design. Add enough heat to the equation and - bingo - down it comes.

The engineer guys know all about this stuff. They've even, like, proven it empirically in real world tests. Go figure.

 

[Sword_Of_Truth]

Since the planes damaged lots of columns in both towers, the loads experienced by the remaining structure were significantly greater than their original design.

Scientists and engineers simulate jet colliding with World Trade Center

The researchers are analyzing how many columns were destroyed initially in the building's core, a spine of 47 heavy steel I-beams extending through the center of the structure, Sozen said.

"Current findings from the simulation have identified the destruction of 11 columns on the 94th floor, 10 columns on the 95th floor and nine columns on the 96th floor," he said. "This is a major insight. When you lose close to 25 percent of your columns at a given level, the building is significantly weakened and vulnerable to collapse."

 

[sylvan8798]

Since the planes damaged lots of columns in both towers, the loads experienced by the remaining structure were significantly greater than their original design. Add enough heat to the equation and - bingo - down it comes..

Not to mention the eccentric and torsional loadings which were not in the original design loads.

 

[jay howard]

The contents of the WTC fire did not release temperature, they released energy. Trying to measure the temperature release is nonsensical.

You're making up problems that don't exist. They didn't use heat-release rate as a standard because the "fire did not release temperature."

What information does heat-release rate provide that time and temperature doesn't or can't? Why do you say it's "nonsensical" to use time and temp?

Furthermore, the air temp in the tests can be inferred from the surface temperature of the materials. I'd have to read through the report again to see if they actually measured the gas temperature itself, but quite frankly: it's really not important or relevant.

The whole point of measuring the gas temps would be so we wouldn't have to infer them. Now we only have more speculation. And as it turns out, a bunch of people here, myself included, use time and gas temp as theoretical criteria with which to judge the likelihood of NIST's answer.

 

[jay howard]

1100 C is 2012F. What are you trying to say here?

There was some confusion about temperature. Just want to be clear. I'm well aware that 1100C is hotter than 1100F.


.

 

[Newtons Bit]

You're making up problems that don't exist. They didn't use heat-release rate as a standard because the "fire did not release temperature."

What information does heat-release rate provide that time and temperature doesn't or can't? Why do you say it's "nonsensical" to use time and temp?

Because time vs. temperature is wholly dependent upon the conditions of the test chamber and cannot be directly applied to a general case. The energy source adds energy to the enviroment in the form of heat. The temperature of the gas is dependent upon the mass of the gas heated (as well as everything else in the environment). If the mass is a variable, or changing (such as non-closed environment of the WTC) then would have to do a bunch of thermodynamic gymnastics to convert your non-nonsensical time vs. temperature into an energy release rate that NIST used in the first place. Furthermore, time vs. temperature wouldn't account for an object being directly above an actual flame source. It would only account for heating from the ambient gas temperature.

The whole point of measuring the gas temps would be so we wouldn't have to infer them. Now we only have more speculation. And as it turns out, a bunch of people here, myself included, use time and gas temp as theoretical criteria with which to judge the likelihood of NIST's answer.

In any event, the temperature of the gas can be easily computed by hand with a couple of one-line calculations. But as I've said before, it's not relevant. The test was to determine if the thermal property variables and the coarseness of the FEA mesh used for the FDS is closely correlated with a physical test.

Which of course they did.

So why is it that you're demanding information that isn't relevant to the purpose of the test? Why are you calling the designers incompetent when their test did exactly what it was supposed to?

 

[A W Smith]

Jay? how does the heat from the sun reach us through the vaccum of space?

So why is it that you're demanding information that isn't relevant to the purpose of the test? Why are you calling the designers incompetent when their test did exactly what it was supposed to?

Because if Jay can infer that heat energy can only be transferred to the steel via air temperature, Then he can set up a straw man and hand wave off energy transfer through direct flame contact, and radiation. And make a spurious claim that "the fires weren't hot enough"

http://en.wikipedia.org/wiki/Heat

http://en.wikipedia.org/wiki/Thermal_radiation

 

[jay howard]

No, a car's speedometer can have any upper limit one wanbts to put on it with no verification required that the vehicle could ever reach that. the chimney standards are there to allow a one time chimney fire to occur without causing a fire to the structure. If you have had a chimney fire then the chimney is no longer assumed to be able to still meet the standard and should be replaced. What does that say about the temps reached jay? That its all just a make-believe.



A chimney fire creates its own forced draft.

There's nothing to argue about here. Your own fireplace ratings are in agreement with what I said about naturally-aspirated hydrocarbon fires:

The ULC code specifies:
Max Continuous 650°C (1200°F)
Brief Forced Firing 925°C (1700°F)
Tested To 1150°C (2100°F)

Hmmm, I wonder why?

,and at 500C a steel structural member that is already experiencing loads it was not normally designed to withstand it may well fail.

That's an interesting theory. Is there any empirical data from controlled tests in the NIST report to back that up?

 

[jay howard]

Err, that's a couple thousand degrees Farenheit. That's mighty hot, lad.

Are you familiar with viscoplastic buckling? Look it up. Depending on the load experienced, steel will fail at temps below 500C.....way below that actually.

Since the planes damaged lots of columns in both towers, the loads experienced by the remaining structure were significantly greater than their original design. Add enough heat to the equation and - bingo - down it comes.

The engineer guys know all about this stuff. They've even, like, proven it empirically in real world tests. Go figure.

So, it's your professional engineering understanding that 500C fire (gas temp) is equivalent to 500C steel temps?

Who was it that was trying to tell me I didn't understand something about temp and heat?

I think that you don't fully understand the difference between temperature & heat.

I'm sure s/he'll comment on your misunderstanding here shortly.

 

[funk de fino]

That's an interesting theory. Is there any empirical data from controlled tests in the NIST report to back that up?

There is empirical data to prove the fact steel fails in fires.

here is one such case





There have been tests carried out to prove the fact steel loses a major amount of strength at temps of 600 dec C. It is well known normal house fires can reach temps around 1100 deg C.

http://www.mace.manchester.ac.uk/project/research/structures/strucfire/materialInFire/Steel/HotRolledCarbonSteel/mechanicalProperties.htm

 

[funk de fino]

So, it's your professional engineering understanding that 500C fire (gas temp) is equivalent to 500C steel temps?

Who was it that was trying to tell me I didn't understand something about temp and heat?

Where did you get that straw?