Ya know some parts of those planes never burned at all. Some went straight through the building and out the other side. And it would be plausible that especially one of the terrorist “pilots” items would have been an item to go through the building.
Having done a great deal of structural fire restoration, yes, I've had to replace steel beams and only a few wood joists where the fire was hottest. The steel beam only needs to be compromised in a very small section to ruin it's integrity for the entire piece
It seems counterintuitive until knowing the science. Being a fire service instructor and having gone through the basic fire classes when first getting into the service, combined with a mech engineering background, it’s critical that FFs know the science regarding steel beam construction.
This is one of the reasons strip malls are so dangerous during fires. The fabricated steel trusses fail at surprisingly low fire intensities.
C'mon man, if you've done construction, you know someone screwed up something and wrote an RFI to get the engineer to sign off on what can't be changed and that margin is gone before the building ever sees a fire. Isn't that how the Hard rock cafe in New Orleans came down?
There's way, WAAY too much steel for such a weakening to even start being a remote possibility.
There's not NEARLY enough heat in those fires, and way too much ongoing dissipation.
Steel framed buildings stood after burning much hotter and much longer, plenty of times.
You arm-wave but provide no quantitative rationale. Plenty of heat in a closed-box fireplace burning 50 tons of kerosene. Enough to heat the structural steel to 30% or less of its room-temperature strength. All you need to do is reduce the strength margins to zero for a catastrophic collapse. No ordinary building would have so much high-energy-density fuel to combust. There is some basis for thinking that some of the aircraft aluminum contributed to the combustion.
What about the molten red-hot slag seen pouring out of the building in some footage? Or the fact that they found molten steel in the wreckage? Thay speaks to the steel actually melting, not just softening.
I've seen molten aluminum in junior high school metal shop. It is mostly a silver color with some red highlights. But helenofthewest said steel was found, not "metal." Shouldn't you close the loop on that?
Molten aluminum would bring another actor into the play: combustion of aluminum vapor. The adiabatic flame temperature of aluminum burning in oxygen is 3,732 C (6,750 F). Combustion of aluminum would leave aluminum oxide ash...which can easily be misidentified as residue of "thermite." (Yeah, yeah. Aluminum's boiling point is a lot higher, but the aluminum does not have to boil in order to have a vapor pressure. Puddles of water on the sidewalk eventually evaporate at ambient temperature without boiling. Same principle.) Aluminum is the main fuel component of large solid rocket motors.
And how many buildings have you seen afire from 50 tons of kerosene poured into it at a high level? There are no comparable events, or they would have been referenced by now.
This meme is stupid and works against your credibility. Does steel have to melt to get weak? At what temperature does steel degrade below spec?
What planet are you from? Passport found on street below magically appeared.
Im not saying its all as reported. Im commenting on the meme alone.
Ya know some parts of those planes never burned at all. Some went straight through the building and out the other side. And it would be plausible that especially one of the terrorist “pilots” items would have been an item to go through the building.
I don't think those of us with different opinions on some parts are denying it was planted.
Steel begins to lose structural integrity around 1000 deg.
Having done a great deal of structural fire restoration, yes, I've had to replace steel beams and only a few wood joists where the fire was hottest. The steel beam only needs to be compromised in a very small section to ruin it's integrity for the entire piece
It seems counterintuitive until knowing the science. Being a fire service instructor and having gone through the basic fire classes when first getting into the service, combined with a mech engineering background, it’s critical that FFs know the science regarding steel beam construction.
This is one of the reasons strip malls are so dangerous during fires. The fabricated steel trusses fail at surprisingly low fire intensities.
Thanks for the added info.
You have a LOT of homework to do, especially in physics.
That would have to include you. If steel loses 80% of its strength, all the structural margins are gone and collapse is the inevitable result.
C'mon man, if you've done construction, you know someone screwed up something and wrote an RFI to get the engineer to sign off on what can't be changed and that margin is gone before the building ever sees a fire. Isn't that how the Hard rock cafe in New Orleans came down?
Your point eludes me. Are you saying there is cause to suspect the buildings to have been faulty in their construction?
BTW, thank you for being a voice of reason
And thank you for noticing. I sometimes feel like a steel column withstanding the crash of fixed minds...
There's way, WAAY too much steel for such a weakening to even start being a remote possibility. There's not NEARLY enough heat in those fires, and way too much ongoing dissipation.
Steel framed buildings stood after burning much hotter and much longer, plenty of times.
You arm-wave but provide no quantitative rationale. Plenty of heat in a closed-box fireplace burning 50 tons of kerosene. Enough to heat the structural steel to 30% or less of its room-temperature strength. All you need to do is reduce the strength margins to zero for a catastrophic collapse. No ordinary building would have so much high-energy-density fuel to combust. There is some basis for thinking that some of the aircraft aluminum contributed to the combustion.
Unless youve done the math and can show us, your guess is as good as anyone elses.
What about the molten red-hot slag seen pouring out of the building in some footage? Or the fact that they found molten steel in the wreckage? Thay speaks to the steel actually melting, not just softening.
And thats pure aluminum. Plenty of alloys have lower melting points.
I've seen molten aluminum in junior high school metal shop. It is mostly a silver color with some red highlights. But helenofthewest said steel was found, not "metal." Shouldn't you close the loop on that?
Molten aluminum would bring another actor into the play: combustion of aluminum vapor. The adiabatic flame temperature of aluminum burning in oxygen is 3,732 C (6,750 F). Combustion of aluminum would leave aluminum oxide ash...which can easily be misidentified as residue of "thermite." (Yeah, yeah. Aluminum's boiling point is a lot higher, but the aluminum does not have to boil in order to have a vapor pressure. Puddles of water on the sidewalk eventually evaporate at ambient temperature without boiling. Same principle.) Aluminum is the main fuel component of large solid rocket motors.
I have watch enough demolition and fire on building to know this isn't a simple fire from jet fuel.
And how many buildings have you seen afire from 50 tons of kerosene poured into it at a high level? There are no comparable events, or they would have been referenced by now.
Im sure you have TONS of jet fuel fire in skyscraper experience. How hot can jet fuel get?