WTC7 - The fires failed Girder 44-79

[Miragememories]

"No?

Then why did you put emphasis on column 79 with qualifying words such as and "fire protected" in your explanation?

What does column 79 being "fire protected" have to do with the NIST's explanation of how column 79 buckled?"

"Emphasis on 'fire protected'?

"A lower floor, heavy steel, fire-protected, undamaged, column."

After the collapse of WTC1, that 'was' the true condition of column 79.

I am well aware that the NIST hypothesis is based on the premise that heat-induced steel expansion lead to a sudden loss of lateral support for column 79 over 5 floors, causing it to buckle.

And I think it is important that it be noted that this critical column was fire-protected against ill effect from those passing office cubicle fires."

Yes, fire protected for up to TWO (2) hours. Not 5, not 7, TWO.

TWO hours. WITH proper adhesion. We know, from experience, that SFRM has one major weakness. Application must be done PERFECTLY.

I don't know the condition of the SFRM in 7WTC, but maybe someone else does. However, having dealt with the stuff time and time again, very few are done perfectly.

Still, even applied perfectly, it's still only rated for TWO hours. Not seven.
And why do you keep saying "passing" fires? Does heat not radiate in your world?

My point uses the NIST's own findings from their Final Report on the Collapse of WTC7.

In their investigation of the WTC7's thermal response to an induced-fire, the NIST in their Findings chapter,
found that; local temperatures in "some structural components" were significantly weakened by high temperature. In the next sentence they state that "Other structural components, protected by SFRM, remained relatively cool."

The NIST go on to also state that in all of their cases the critical columns, 79, 80 or 81, maintained temperatures below 200C on all of the floors.

You are claiming the SFRM should be totally spent after so many hours beyond its rating and I would agree but.

The NIST appear to think otherwise.

The NIST have created a simulation that shows those columns not receiving enough sustained fire and heat exposure to damage the effectiveness of the SFRM.

That would indicate that the NIST must have concluded there was insufficient fire and/or heat concentrated in the area surrounding those 3 columns on all the floors.

Since the crux of the NIST's WTC7 collapse hypothesis is dependent on the fires producing heat of sufficient magnitude and duration to expand floor steel over 5.5 inches and dislodge the lateral girders stabilizing column 79, the fact that the column SFRM was holding up so well has relevance.

Whatever heat data the NIST used in their final simulation, it should not have allowed the SFRM to fail on those 3 columns.

So now we have less than 2 hours of SFRM-destroying heat and fire activity in the area surrounding those 3 columns on all floors.

MM

 

[Animal]

My point uses the NIST's own findings from their Final Report on the Collapse of WTC7.

In their investigation of the WTC7's thermal response to an induced-fire, the NIST in their Findings chapter,
found that; local temperatures in "some structural components" were significantly weakened by high temperature. In the next sentence they state that "Other structural components, protected by SFRM, remained relatively cool."

The NIST go on to also state that in all of their cases the critical columns, 79, 80 or 81, maintained temperatures below 200C on all of the floors.

You are claiming the SFRM should be totally spent after so many hours beyond its rating and I would agree but.

The NIST appear to think otherwise.

The NIST have created a simulation that shows those columns not receiving enough sustained fire and heat exposure to damage the effectiveness of the SFRM.

That would indicate that the NIST must have concluded there was insufficient fire and/or heat concentrated in the area surrounding those 3 columns on all the floors.

Since the crux of the NIST's WTC7 collapse hypothesis is dependent on the fires producing heat of sufficient magnitude and duration to expand floor steel over 5.5 inches and dislodge the lateral girders stabilizing column 79, the fact that the column SFRM was holding up so well has relevance.

Whatever heat data the NIST used in their final simulation, it should not have allowed the SFRM to fail on those 3 columns.

So now we have less than 2 hours of SFRM-destroying heat and fire activity in the area surrounding those 3 columns on all floors.

MM

That thermal resistance / transmitance varies from the veritcal to the horizontal is a known fact (and has been for decades)
Your ignorance of known simply concepts proves you have no clue what straws you are grasping at.

 

[Justin39640]

My point uses the NIST's own findings from their Final Report on the Collapse of WTC7.

In their investigation of the WTC7's thermal response to an induced-fire, the NIST in their Findings chapter,
found that; local temperatures in "some structural components" were significantly weakened by high temperature. In the next sentence they state that "Other structural components, protected by SFRM, remained relatively cool."

The NIST go on to also state that in all of their cases the critical columns, 79, 80 or 81, maintained temperatures below 200C on all of the floors.

You are claiming the SFRM should be totally spent after so many hours beyond its rating and I would agree but.

The NIST appear to think otherwise.

The NIST have created a simulation that shows those columns not receiving enough sustained fire and heat exposure to damage the effectiveness of the SFRM.

That would indicate that the NIST must have concluded there was insufficient fire and/or heat concentrated in the area surrounding those 3 columns on all the floors.

Since the crux of the NIST's WTC7 collapse hypothesis is dependent on the fires producing heat of sufficient magnitude and duration to expand floor steel over 5.5 inches and dislodge the lateral girders stabilizing column 79, the fact that the column SFRM was holding up so well has relevance.

Whatever heat data the NIST used in their final simulation, it should not have allowed the SFRM to fail on those 3 columns.

So now we have less than 2 hours of SFRM-destroying heat and fire activity in the area surrounding those 3 columns on all floors.

MM

You really don't understand the difference that size, thickness, orientation makes when talking about how fires (of the same size) heat steel?

Really?

 

[Justin39640]

That thermal resistance / transmitance varies from the veritcal to the horizontal is a known fact (and has been for decades)
Your ignorance of known simply concepts proves you have no clue what straws you are grasping at.

Seriously. There's reasons you don't build fires with the logs sticking straight up and down.

 

[Animal]

Seriously. There's reasons you don't build fires with the logs sticking straight up and down.

There is reasons why building codes require more insulation in a ceiling than in a wall too.

 

[thedopefishlives]

Indeed. And the residual heat can be pretty intense. Fire crews can spend many hours - days even - damping down the remains of major fires to prevent re-ignition.

On a much smaller scale I've had bonfires of tree prunings whose embers, when reloaded the next morning, were still hot enough to eventually ingite the new fuel.

Truther mentality is remarkably literal. "The fire had passed by col 79 at 3:30" (or whatever) apparently equates to "So we can assume that area was back to normal room temperature". Weird. I can only guess it involves a subconcious switching-off of all knowledge and personal experience in order to allow the delusion to survive, against whatever odds. I think R.Mackey wrote a big fat paper on the subject

When Chris Sarns was still active here, I was involved in several lengthy arguments with him that basically centered around this point. He used MS Paint to draw a very pretty picture of what he felt the fire behavior really was, then spent considerable time and energy murdering the heck out of his strawman. He simply refused to understand the idea that "flames being gone" != "everything back to normal".

 

[Gamolon]

Post #613 MM.

Can you please explain what your definition of "universal engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?

So please. Explain to us all what "universal engineering science" was utilized to foresee and prevent that column failure.

Basically what you're claiming with your "no steel framed tower has ever collapsed before" and "same universal engineering science" garbage is that structural engineers have figured out how to make towers 100% impervious fires and can 100% guarantee that any building they design will NEVER, EVER suffer a global collapse.

Ask any structural engineer if they will guarantee this.

 

[Miragememories]

"And why do you keep saying "passing" fires? Does heat not radiate in your world?"

Indeed. And the residual heat can be pretty intense. Fire crews can spend many hours - days even - damping down the remains of major fires to prevent re-ignition.

On a much smaller scale I've had bonfires of tree prunings whose embers, when reloaded the next morning, were still hot enough to eventually ingite the new fuel.

Truther mentality is remarkably literal. "The fire had passed by col 79 at 3:30" (or whatever) apparently equates to "So we can assume that area was back to normal room temperature". Weird. I can only guess it involves a subconcious switching-off of all knowledge and personal experience in order to allow the delusion to survive, against whatever odds. I think R.Mackey wrote a big fat paper on the subject

Because it is all about the heat.

How much, how long, and where.

The NIST pointed at estimated slab portions reaching a temperature of 600C, a point where steel is expected to lose half its strength.

So if the floors in the Twin Towers sagged under the rising heat of office cubicle fires, why did the WTC7 floors stay rigid and push outward 5.5 inches?

That is quite an expectation when the best they can do is a 600C indication for only a portion of floor slabbing.

Kevin Ryan estimated that beams and girders fully heated to 600C "experience a maximum of 2.2 inches of deflection". And less deflection will occur in lengths of steel where the heating is not uniform.

And then there is the issue of the thermal conductivity of steel which is normally considered to be 46 W/m/K.

The NIST assigned an almost zero thermal rating to the interior steel columns, which would have provided excellent heat wicking where they connected with girders.

The NIST acknowledged that WTC7 complied with New York City Building Code, requiring fire resistance of 3 hours for columns and 2 hours for floors.

In a question and answer session, the NIST's Shyam Sunder said; "The fires moved from location to location, meaning that at any given location the combustibles needed about 20 minutes to be consumed. While the combustibles at a location were being consumed, the fire front would be progressing to adjacent combustibles."

How could these well vented migrating office fires possibly concentrate 600C temperatures long enough to over come each floor's 2 hour fire protection and then maintain enough heat to extend the floor steel 5.5 inches?

On the critical floor 12, where the NIST fire model showed the 13th floor steel over-expanding, photo evidence at 4:48 p.m. indicates the fire had been and gone.

Yet we are expected to believe there was enough residual heat in that burned-out 12th floor location to keep the steel hot enough to continue expanding until 5:20 p.m.?

MM

 

[Justin39640]

Um... heat and temperature are two different things and Sunder is talking about the fire front and how it was consuming fuel. Not how the area was being heated. Again, two different things.

I would love to see the vision you have of this horrific office fire. It almost seems as if you have a very sanitary view of it.

 

[Oystein]

MM? Can you please explain what your definition of "universal engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?

 

[000063]

Call me crazy, but I believe it's another psuedosciency impressive-sounding term he or another truther made up with no objective or commonly accepted definition.

Just a hunch.

MM, fire science was in its infancy when WTC was built. Any fire predictions would be little better than guesses compared to even 2001's fire science.

 

[Miragememories]

"Sure WTC7 was an unusual building. But the same universal engineering science of the time was applied to its design and construction.

Under-engineering the lower floors of WTC7 was last thing building engineers wanted to do.

Primarily because of the power sub station it was built over, but they also wanted the lower floors to be customizable for new clients..

Most surprisingly, given the sensational nature of the NIST steel-expansion claim, nothing to support their hypothesis appears to have been discovered in the investigations of all the impressive, largely unfought steel office tower fires that occurred before 2001.

Not a clue suggesting that the fire in WTC7 would be so special."

"MM? Can you please explain what your definition of "universal engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?"

Maybe if I substitute common, standard, or familiar, it might assist you in grasping my meaning?

In the long engineering history of steel-structured office towers, there has never been any fire event that threatened or achieved a total structural collapse.

There is nothing supporting an exception to this well established history.

The NIST steel-expansion hypothesis is poorly argued and is based on a 'new' look at a scientific phenomenon that is very familiar to steel construction engineers. They are well aware that heated steel expands and weakens, and that cooling steel contracts and strengthens.

The NIST hypothesis is dependent on "old news" and with supporting legs so weak, that the hypothesis totally collapses when examined.

MM

 

[Animal]

Because it is all about the heat.

How much, how long, and where.

The NIST pointed at estimated slab portions reaching a temperature of 600C, a point where steel is expected to lose half its strength.

So if the floors in the Twin Towers sagged under the rising heat of office cubicle fires, why did the WTC7 floors stay rigid and push outward 5.5 inches?

For starters.....the differences between open web joists and a rolled steel section. If you cannot figure out the difference or why the difference may affect the performance under fire, you have no business saying anything about NIST.

That is quite an expectation when the best they can do is a 600C indication for only a portion of floor slabbing.

Kevin Ryan estimated that beams and girders fully heated to 600C "experience a maximum of 2.2 inches of deflection". And less deflection will occur in lengths of steel where the heating is not uniform.

Why troofers rely so much on an unqualified water tester to due structural calculations is beyond me.

And then there is the issue of the thermal conductivity of steel which is normally considered to be 46 W/m/K.

The NIST assigned an almost zero thermal rating to the interior steel columns, which would have provided excellent heat wicking where they connected with girders.

The "wicking" claim......one of the foundations of troofer science.
http://www.youtube.com/watch?v=Drsgs6-3Qlg
Please note the bare hands.

The NIST acknowledged that WTC7 complied with New York City Building Code, requiring fire resistance of 3 hours for columns and 2 hours for floors.

So.....the conventional wisdom at the time was that columns were more important and critical than floors.

In a question and answer session, the NIST's Shyam Sunder said; "The fires moved from location to location, meaning that at any given location the combustibles needed about 20 minutes to be consumed. While the combustibles at a location were being consumed, the fire front would be progressing to adjacent combustibles."

How could these well vented migrating office fires possibly concentrate 600C temperatures long enough to over come each floor's 2 hour fire protection and then maintain enough heat to extend the floor steel 5.5 inches?

Your ignorance of fire science and the difference between fire location and heat make you unwualified to even comment.

On the critical floor 12, where the NIST fire model showed the 13th floor steel over-expanding, photo evidence at 4:48 p.m. indicates the fire had been and gone.

Yet we are expected to believe there was enough residual heat in that burned-out 12th floor location to keep the steel hot enough to continue expanding until 5:20 p.m.?

MM

For starters.......learn about structural creep.

 

[Oystein]

Maybe if I substitute common, standard, or familiar, it might assist you in grasping my meaning?
...

No, but a definition might help

But as you wish:

Can you please explain what your definition of "common engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?

or

Can you please explain what your definition of "standard engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?

or

Can you please explain what your definition of "familiar engineering science" is and how it would have been applied to WTC7's design in order to prevent it from suffering a global collapse due to every possible fire scenario?


and how its application ensures that buildings are 100% safe from fires?

 

[Gamolon]

Maybe if I substitute common, standard, or familiar, it might assist you in grasping my meaning?

In the long engineering history of steel-structured office towers, there has never been any fire event that threatened or achieved a total structural collapse.

I'll ask again since you seem to be avoiding these questions.

What is this "common", "standard", "familiar", or "universal" engineering science you are referring to? Are you suggesting that there is a design code for or common practice followed by structural engineers to prevent a global collapse due to ANY fire scenario?

Is this "design code" the reason that historically, no steel framed tower had ever suffered a total collapse due to fire?

Is this what you are claiming?

 

[pgimeno]

In the long engineering history of steel-structured office towers, there has never been any fire event that threatened or achieved a total structural collapse.

False.

One New York Plaza suffered internal collapses.
Source

Before continuing, a quote worth noting from the above link:

And a huge high-rise fire in Philadelphia in 1991 led federal experts to conclude that tests for assessing structural integrity in fires, dating back to the early 20th century, were technically primitive and unreliable for the high-temperature blazes in offices filled with plastic computers and synthetic furniture.​

Torre Este in Venezuela's Parque Central was also threatening with total collapse (it's a mixed steel/concrete structure):

Si por las altas temperaturas que se están dando el acero cede, podría colapsar la estructura hasta el piso 34, y esto podría hacer que toda la estructura se viniera hacia abajo

[my translation:]

If due to the high temperatures happening the steel gives way, the structure could collapse up to floor 34, and that could cause the whole structure to come down.
​

And for One Meridian Plaza:

After more than 11 hours of uncontrolled fire growth and spread, interior firefighting efforts were abandoned due to the risk of structural collapse.
​

WTC5 suffered also internal collapses. It had its fireproofing in place, yet look:

That they didn't collapse totally was just luck, despite the common, standard, familiar, universal engineering science that was presumably applied to them

 

[000063]

Maybe if I substitute common, standard, or familiar, it might assist you in grasping my meaning?

In other words, just "engineering science". And still no actual definition, or explanation as to how it could've been used to predict every possible scenario. Or even something close to this one.

In the long engineering history of steel-structured office towers, there has never been any fire event that threatened or achieved a total structural collapse.

Unprecedented = / = impossible. You know fire has made steel buildings collapse, and can make steel fail. You know it's expected to. Which is why you've moved the goalposts to "steel-structured office towers".

There is nothing supporting an exception to this well established history.

It happened. That's an exception.

The NIST steel-expansion hypothesis is poorly argued and is based on a 'new' look at a scientific phenomenon that is very familiar to steel construction engineers. They are well aware that heated steel expands and weakens, and that cooling steel contracts and strengthens.

If the steel has failed or shifted while it was hot, then it could very well be weakened compared to its strength originally. I think this is where someone posts that photo of a steel bar, bent by heat. You're trying to imply that once the steel cools, it'll go back to its original strength, which you know is false, especially in this case, where the steel had, in fact, already failed in several areas due to fire. In fact, you've been shown up by two actual firemen, with experience in fire science. And, as pointed out, fire science was barely a thing when WTC 7 was built.

The NIST hypothesis is dependent on "old news" and with supporting legs so weak, that the hypothesis totally collapses when examined.

MM

What "engineering science", specifically, do you claim the builders of WTC 7 had access to that would help them anticipate and prevent the collapse? Not people, engineering. Quit moving goalposts.

 

[Gamolon]

I'll ask again since you seem to be avoiding these questions.

What is this "common", "standard", "familiar", or "universal" engineering science you are referring to? Are you suggesting that there is a design code for or common practice followed by structural engineers to prevent a global collapse due to ANY fire scenario?

Is this "design code" the reason that historically, no steel framed tower had ever suffered a total collapse due to fire?

Is this what you are claiming?

Are you ever going to answer this MM? Or are you stymied and don't want to give your answer because you know where it will lead?

 

[Gamolon]

MM,

If a steel tower can partially collapse from fire, what is stopping one from totally collapsing?

 

[Loss Leader]

Please stay civil and discuss the topic, not other posters.

Posted By: Loss Leader