Chemistry/Physics Behind the Attacks

I've heard and read about many conspiracy theories regarding what "really happened" on September 11th. Many of them make interesting points, but all too often, these points reside along coincidence. Its true that an observer can make inferences based on these coincidences, but thats all it is: an inference. It can never be verified to be right, wrong, on target or off, until somebody with the knowledge comes forward. And since that doesn't seem to be happening, I believe we should look at the chemistry and physics behind the attacks in an attempt to prove (or at least gather more than circumstantial evidence) what happened on that day. I believe that science can help explain this best of all. And so, I think we should focus our efforts in that area, rather than in circumstantial evidence, however attractive it might be.

To start us off, I have a few questions that I wonder if anybody knows the answers to:

1.) What is jet fuel composed of?
2.) What is the maximum temperature that jet fuel can attain?
3.) What is the maximum temperature that the raw steel used in the towers could endure before losing strength?
4.) Just how were the towers constructed? Was the support mainly in the steel columns? Or was the support spread throughout the building? (any available blue-prints would be greatly appreciated)
5.) Upon learning more about how the towers were constructed, what would be the maximum load that any one portion of the load-bearing structure could hold?
6.) Besides the steel frames, what would be the maximum temperatures that any other loading bearing structures could withstand?
7.) What else was present in the towers where the planes hit besides steel and jet fuel?

I believe that number four is the most important. How the weight of the building was supported is very important. If threads such as this already exist, feel free to point me in the right direction and close this one.

[edit on 12-2-2006 by aggroskater]

Read up on www.st911.org for example, these are old questions actually, and their answers are all over the place.

1) Jet fuel consists of hydrocarbons in the range of c10h22-c16h34

2) This depends a lot on atmospheric conditions. Generally, the better the oxygen supply, the hotter. Under standard atmospheric conditions, around 800°C can be attained.

3) Steel loses strength gradually when heated. Melting point is at around 1500°C. See this diagram:

4) 47 core columns bearing approx. 60% gravitic load, 220 (or so) perimeter columns bearing the remaining 40%.

5) Impossible to answer. Safety standards seem to dictate overload factors of 3-6, i.e. the actual load may only be 1/3-1/6 of the maximum certified load.

6) Probably irrelevant, as the loadbearing structure apparently was steel only. Rumour has it that the core sported concrete, but we don't know.

7) Offices?


It's important to note that for the cap of the towers to fall (as evidenced), the core columns would have to give way, simultaneously. As there supposedly wasn't much combustible material within and it was lacking actual floors to accomodate the jet fuel, that's more than unlikely. Also note that multiple severe highrise fires did not substantially compromise the loadbearing structure of other buildings.

And then we have video evidence of relatively extensive damage to the lobby, that, according to eyewitnesses, was caused by a detonation in the sub-basement simultaneous to the aircraft impacts.

Originally posted by Lumos
2) This depends a lot on atmospheric conditions. Generally, the better the oxygen supply, the hotter. Under standard atmospheric conditions, around 800°C can be attained.

I think 800°C is more of the upper range of hydrocarbon fires, but I could be mistaken. I honestly haven't read much on the nature of your average hydrocarbon fires.

Either way, they won't go much beyond 800°C, and steel is a good heat sink. Tons upon tons upon tons of steel, even moreso. 800°C of fire, spread out amongst literally tons of steel, isn't going to make for very hot steel.

Thus, you saw no glowing of steel at either WTC Tower on 9/11, when steel will begin giving off photons at somewhere around 400°C. Still won't lose critical strength until heated to around 600°C, and the WTC Towers needed to lose about 60% more integrity than the initial impacts caused for any given floor to collapse. So, even in ideal conditions, it would be damned near impossible for the fires in the WTC towers to have sufficiently weakened the steel.

4.) Just how were the towers constructed? Was the support mainly in the steel columns? Or was the support spread throughout the building? (any available blue-prints would be greatly appreciated)

The buildings consisted of perimeter and core columns, which were linked by trusses between floors. All of that was made of steel. The core columns probably held the good majority of the gravity load; I've seen it 50/50, and 60/40, and it was Howard saying 50/50 so I'm betting that he's skewing it to make the buckling thing more credible. I think the 60/40 thing was given in a NIST presentation, and it came to me via a paper by Wayne Trumpman. Since NIST was giving the 60/40 figure, don't bet on that being entirely accurate, either.

The core columns were in the middle of the buildings, and there were offices built within them. The stairwells were within the core structure, if I remember correctly, and the elevators. The core columns could likely hold some lateral loads as well as much vertical load, so theoretically, the core structures would have been able to stand perfectly well without the perimeter columns and trusses, but would probably be much more vulnerable to wind (such loads were taken by the perimeter columns and trusses). In a video of the collapse of WTC1 from Hoboken, you can see parts of the core of WTC still standing after all of the perimeter columns and trusses have fallen away.

There were concrete slabs, about 4 inches thick, between each floor.

The construction drawings of the towers are classified and are not publicly available.

5.) Upon learning more about how the towers were constructed, what would be the maximum load that any one portion of the load-bearing structure could hold?

Ok, first of all let me say that this may be horribly inaccurate. We don't have the construction papers, so we don't know this for sure.

But Wayne Trumpman's paper, which you can find here, claims that each floor could withstand, on average, 11,075 tons of load before failing. This number would likely widely vary, between stronger columns were used in the bottoms of the towers, and the higher floors were lighter and not as strong.

The specific part of Trumpman's paper that I'm referencing says the following:

The factor of safety is based upon the dead load (building materials) of the building and the intended live load (people, office furniture, and similar). The dead load of a floor was 1,818 tons. The floor area was rated 40-150 psf (1.9-7.18 kPa), depending on what the area was going to be used for. Higher load ratings generally were for areas that would support larger than normal loads such as mechanical equipment. Below are floor load estimates based on a review of WTC data contained in a 2005 NIST report. This report contained select scanned images of original WTC specification documents. Because of contradictions in the NIST final report this paper relied on the original WTC specification documents. Data was incomplete so inferences had to be made. The load rating for columns in the perimeter area was 50 psf. The load rating for the core area was up to 100 psf. This comes out to be an estimated 75 psf average for an office floor. The load ratings for floors 110-94 average out to be about 82 psf (3.9 kPa) per floor. On average, a floor's design live load was 1,488 tons. The estimated total weight of a floor, dead load plus live load, is 3,306 tons. Add the factor of safety and the building structure could handle multiple times this load. It is estimated that the average factor of safety for a floor was 3.35. This means a floor could handle a total of 11,075 tons before failing. To visualize, imagine 5,500 2-ton cars stacked in a square about 1/3 of a city block.

6.) Besides the steel frames, what would be the maximum temperatures that any other loading bearing structures could withstand?

This depends upon how much weight is being supported, and how much strength would be lost at what temperatures.

At around 600°C, steel loses about half its integrity. At around 250°C, steel has lost none of its integrity, or at least so little that it's not even notable. The steel NIST tested shows no steel heated above 250°C; that is to say, 250°C was around the max that NIST detected. You can rest assured that no steel was heated much above 400°C, as it would have started glowing and would have been visible in broad daylight.



Source, and additional information.

You can see that, even at 400°C, very little strength is lost!

If you want, I can hunt down the page that details steel giving off photons at 400°C. AgentSmith actually found this for me, so you can cross reference with him if you'd like; I would have to go back and look for it, but can get it if you want a source for that.

7.) What else was present in the towers where the planes hit besides steel and jet fuel?

Some paper; plastic. Concrete, asbestos, and Gypsum, I think. People.

I believe that number four is the most important. How the weight of the building was supported is very important. If threads such as this already exist, feel free to point me in the right direction and close this one.

This info has been capped and recapped time and again throughout a lot of threads here, but going back to find the information is quite some work, so no complaints. I can't blame you. Someone really needs to put together this info, and make it a sticky.

Edit: I'm getting my ex's and quote's mixed up.

[edit on 12-2-2006 by bsbray11]

Anybody hear live in New York City? If so, drive down the West Side Highway, and at about 96th street you will see what remains of a warehouse pier. The pier caught fire. What is left is a pile of twisted metal beams. Metal weakens and twists relatively easy when it is heated.

Surrounding steal in concrete is what protects most high-rise buildings from collapsing due to weakened steel. The WTC had no such protection around its steel. Steel in such a building is sprayed with an insulation to protect it from heat. It is speculated that much of the insulation was blown off the steel during the initial explosion, and that the intense fires exceeded the remaining insulation's fire rating.

As for the people that say jet fuel only burns at such-and-such a temperature, you need to take into consideration that it wasn't just jet fuel burning. It was sheet rock, doors, chairs, office furniture, carpeting, etc. soaked in jet fuel that was burning.

Craig, if that were true, how do all those nonfatal highrise fires fit in? What about the Cardington fire tests? What about NIST's published steel analysis finding few members above 250°C and no members above 650°C? What about the pictures of people within the impact holes? What about the firemen up in the south tower reporting "isolated pockets of fire" that they should be able "to knock down with 2 lines"? What about the apparent damage to the lobby? What about WTC7?

edit: tags

[edit on 13-2-2006 by Lumos]

Originally posted by Lumos
Craig, if that were true, how do all those nonfatal highrise fires fit in?

I cannot speak for the other buildings, but the Meridian Plaza Building in Philadelphia is constructed of concrete and granite encased steel, and the One New York Plaza building was constructed of concrete encased steel. These buildings were not of the same design as the WTC buildings. Also, fire needs three things to burn: oxygen, fuel, and heat. In normal building fires, the sprinkler systems go a long way to control the spread of the fire by wetting the fuel and keeping the temperatue of the fuel cooler than if it is dry. In the case of the WTC, most of the sprinklers failed due to the sprinkler risers being severed by the initial impacts.

Originally posted by LumosWhat about the Cardington fire tests?

Reading this report gave me a headache! The buildings mentioned and the subsequent tests were conducted on buildings under construction, not on buildings completed and under full occupancy load. The load on the WTC buildings was much greater than on the buildings sited in the report. Also, metal weakens over time due to metal fatigue. We need to take into consideration 30 years of stresses from weight, wind flex, etc. on the WTC. Also, these buildings were not full of carpeting, sheet rock, office furniture, wall vinyl, office supplies, etc. that basically became "wicks"... In the WTC these items became soaked in jet fuel and then burned unchecked.

Originally posted by LumosWhat about NIST's published steel analysis finding few members above 250°C and no members above 650°C?

Not quite sure what you mean by this. Do you mean that they found steel beams at that temperature in the debris after the collapse? Heating steel to these temperatures would not melt it or cause it to glow, however, that heat would certainly weaken the steel.

Originally posted by LumosWhat about the pictures of people within the impact holes?

What about them? Many of them jumped to avoid the searing heat they were faced with. They could not reach the exit stairs because the raging fires were blocking their escape routes, so they preferred to die by jumping than die by burning.

Originally posted by LumosWhat about the firemen up in the south tower reporting "isolated pockets of fire" that they should be able "to knock down with 2 lines"?

What about them? What floor where they on? There were small pockets of fire reported as low as the 65th floor in the south tower that I know of; maybe someone can provide more accurate information as to what the lowest floor fire was reported on through the FDNY transcripts that have been published. Anyone who was there that day knows that the firefighters never made it up to the actual floors where the fires were intensely burning. Not one drop of water was put on the fires by FDNY.

Originally posted by LumosWhat about the apparent damage to the lobby?

One possible cause and one definite cause. Possible: The buildings were designed to flex and sway a certain amount for wind. Is it possible that the impact of a large airplane at full speed caused the building to flex to a greater degree than it was designed for? Definite: The debris falling from the building (plane parts, building parts, glass, bodies, office furniture, etc.) didn't just fall 90 stories and hit the ground gently. They fell and literally exploded when they hit the ground. Shrapnel from these falling objects broke many windows. Police officers also used their weapons to shoot out many of the glass window panes to facilitate evacuation. Also, several elevators had their cables completely severed by the impact and their safety brakes failed, causing them to crash into the bottom of their shafts. The bottom of their shafts in some cases were at the lobby level, blowing debris out of the shaft into the lobby.

Originally posted by LumosWhat about WTC7?

WTC 7 had a large quantity of diesel fuel stored in it for the emergency generator in the Office of Emergency Management's generator. This fuel burned unchecked for many hours, again with no firefighting.


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Originally posted by craig732
Surrounding steal in concrete is what protects most high-rise buildings from collapsing due to weakened steel.

Actually, all high rise's I've heard of that use concrete only have steel rebar and not big thick beams like you would see in the WTC Towers. When you have thinner steel rebar surrounded by concrete, that doesn't make for a good situation in office fires.

Steel in such a building is sprayed with an insulation to protect it from heat. It is speculated that much of the insulation was blown off the steel during the initial explosion, and that the intense fires exceeded the remaining insulation's fire rating.

This is irrelevant, as you can be SURE that no steel within any WTC building was heated to much above 400 degrees Celsius before its collapse. Like I just pointed out in my last post on this thread, NIST only found evidence of 250 degrees (this was their MAX), and any steel reaching a little above 400 would've glowed and been visible in plain daylight. Alright? The fireproofing would therefore be totally irrelevant because the steel would not be hot enough to lose much integrity anyway.

As for the people that say jet fuel only burns at such-and-such a temperature, you need to take into consideration that it wasn't just jet fuel burning. It was sheet rock, doors, chairs, office furniture, carpeting, etc. soaked in jet fuel that was burning.

Those are all hydrocarbons. Hydrocarbon fires burn at around the temperatures we just described.

Originally posted by aggroskater
1.) What is jet fuel composed of?

Originally posted by Lumos
1) Jet fuel consists of hydrocarbons in the range of c10h22-c16h34

That’s about right. For a general comparison, you can use any data available for kerosene. Jet fuel and kerosene are about the same, although jet fuel is refined a little “cleaner” (fewer PNAs ) and has some extra additives thrown in.

--- ---

Originally posted by aggroskater
2.) What is the maximum temperature that jet fuel can attain?

Originally posted by Lumos2) This depends a lot on atmospheric conditions. Generally, the better the oxygen supply, the hotter. Under standard atmospheric conditions, around 800°C can be attained.

Originally posted by bsbray11
I think 800°C is more of the upper range of hydrocarbon fires, but I could be mistaken. I honestly haven't read much on the nature of your average hydrocarbon fires.

Either way, they won't go much beyond 800°C, and steel is a good heat sink. Tons upon tons upon tons of steel, even moreso. 800°C of fire, spread out amongst literally tons of steel, isn't going to make for very hot steel.

Thus, you saw no glowing of steel at either WTC Tower on 9/11, when steel will begin giving off photons at somewhere around 400°C. Still won't lose critical strength until heated to around 600°C, and the WTC Towers needed to lose about 60% more integrity than the initial impacts caused for any given floor to collapse. So, even in ideal conditions, it would be damned near impossible for the fires in the WTC towers to have sufficiently weakened the steel.

Actually, the 800 degree C information is wrong. This is based on a common mistake where people confuse heat and temperature.

The temperature generated by combustion depends on a number of factors, mainly the temperature of the initial reactants. Temperature is a measure of the average kinetic energy, and thus it is not really a valid measure of the energy released by a reaction, in this case the combustion of a fuel.

A chemical reaction, such as combustion, does, however, have a fixed value associated with it. This is the total energy released, measured in joules. This value is fixed and is independent of the initial temperature of the reactants.

For Jet A fuel, this value is usually given as 42.8 MJ/kg. (megajoules per kilogram)

Now an interesting thing to consider is this:

We are all familiar with the use of the term watt in relation to energy.

Watts are defined as joules/second.

Thus a 1000 watt fire released 1000 joules per second.

How many watts of energy would be released by 1,000 gallons of jet fuel burning up in 5 minutes?

1,000 gallons of jet fuel = about 3066 kg.

thus the combustion of 1,000 gallons of jet fuel in 5 minutes will release around 437 megawatts of energy.

Worth thinking about.

In any case. Stating that jet fuel can only burn at such and such temperature is incorrect.

Even the temperature of a candle flame can exceed 1000 degrees C.

Originally posted by bsbray11
Thus, you saw no glowing of steel at either WTC Tower on 9/11, when steel will begin giving off photons at somewhere around 400°C. Still won't lose critical strength until heated to around 600°C, and the WTC Towers needed to lose about 60% more integrity than the initial impacts caused for any given floor to collapse. So, even in ideal conditions, it would be damned near impossible for the fires in the WTC towers to have sufficiently weakened the steel.

The melting point of aluminum is 660 Degrees C.

At this corner of the building, the fire apparently got pretty hot.

Originally posted by aggroskater
4.) Just how were the towers constructed? Was the support mainly in the steel columns? Or was the support spread throughout the building? (any available blue-prints would be greatly appreciated)

Originally posted by Lumos
4) 47 core columns bearing approx. 60% gravitic load, 220 (or so) perimeter columns bearing the remaining 40%.

Originally posted by bsbray11
The buildings consisted of perimeter and core columns, which were linked by trusses between floors. All of that was made of steel. The core columns probably held the good majority of the gravity load; I've seen it 50/50, and 60/40, and it was Howard saying 50/50 so I'm betting that he's skewing it to make the buckling thing more credible. I think the 60/40 thing was given in a NIST presentation, and it came to me via a paper by Wayne Trumpman. Since NIST was giving the 60/40 figure, don't bet on that being entirely accurate, either.

The core columns were in the middle of the buildings, and there were offices built within them. The stairwells were within the core structure, if I remember correctly, and the elevators. The core columns could likely hold some lateral loads as well as much vertical load, so theoretically, the core structures would have been able to stand perfectly well without the perimeter columns and trusses, but would probably be much more vulnerable to wind (such loads were taken by the perimeter columns and trusses). In a video of the collapse of WTC1 from Hoboken, you can see parts of the core of WTC still standing after all of the perimeter columns and trusses have fallen away.

There were concrete slabs, about 4 inches thick, between each floor.

The construction drawings of the towers are classified and are not publicly available.

The general design is what is called a “framed tube” construction. The WTC towers were not the only structures to use this construction method, but they were one of the first.

The exterior columns were designed to withstand all of the lateral loads and approximately 50 percent of the gravity loads.

The core was not designed to resist lateral loads, but it supported 50 % of the gravity loads.

This makes sense when you realize that the floor slabs were hung between the core and the exterior, transferring their loads evenly on both ends.

There was no diagonal bracing in the core area, so it’s ability to resist lateral loads would have been based solely on the ability of the column/beam connections to resist leveraged twisting. (in other words, lateral stiffness would have been almost non-existent).

In addition, the core columns were connected to the exterior columns via the floor trusses, and also via the “hat truss” at the top of the building.

There would have been no office spaces within the core area. The core area consisted of duct and pipe shafts, elevator shafts, the elevator lobbies, stairwells, and the toilets.

The designs of the buildings are not classified. Enough information is available for any reasonably competent engineer to understand the structural system. The NIST reports have numerous design documents in the appendices.

Originally posted by aggroskater
5.) Upon learning more about how the towers were constructed, what would be the maximum load that any one portion of the load-bearing structure could hold?

Originally posted by Lumos
5) Impossible to answer. Safety standards seem to dictate overload factors of 3-6, i.e. the actual load may only be 1/3-1/6 of the maximum certified load.

Originally posted by bsbray11

5.) Upon learning more about how the towers were constructed, what would be the maximum load that any one portion of the load-bearing structure could hold?

Ok, first of all let me say that this may be horribly inaccurate. We don't have the construction papers, so we don't know this for sure.

But Wayne Trumpman's paper, which you can find here, claims that each floor could withstand, on average, 11,075 tons of load before failing. This number would likely widely vary, between stronger columns were used in the bottoms of the towers, and the higher floors were lighter and not as strong.

The specific part of Trumpman's paper that I'm referencing says the following:
(edited, see above – HR)

aggroskater, may I direct you to the NIST structural analysis. The answers to many of your questions can be found there.

Trumpman's analysis is fraught with errors. In addition, I have yet to see any indications of his credibility. i.e. is he an engineer?

In any case, the issue here is not all that simple, since you have to try and calculate the affect on the impact and fire damage on the building, and how loads were redistributed as the structural integrity of various portions of the building was compromised.
Additional data

Originally posted by aggroskater
6.) Besides the steel frames, what would be the maximum temperatures that any other loading bearing structures could withstand?

Originally posted by Lumos
6) Probably irrelevant, as the loadbearing structure apparently was steel only. Rumour has it that the core sported concrete, but we don't know.

No, Lumos, no concrete was applied to the beams in the core area (in spite of the BBC illustration to the contrary, yes the BBC makes mistakes too)

Originally posted by bsbray11
This depends upon how much weight is being supported, and how much strength would be lost at what temperatures.

At around 600°C, steel loses about half its integrity. At around 250°C, steel has lost none of its integrity, or at least so little that it's not even notable. The steel NIST tested shows no steel heated above 250°C; that is to say, 250°C was around the max that NIST detected. You can rest assured that no steel was heated much above 400°C, as it would have started glowing and would have been visible in broad daylight.

The NIST report did not show that none of the steel was heated above 250 degrees. It stated that the two pieces of steel recovered from the core region on the impact floors, were not heated above those temperatures. To infer that the rest of the steel on those floors was not heated above those temperatures is faulty logic at best and deliberately disingenuous at worst.

Back to aggroskater’s question. This is in fact a very good question. If I may rephrase it:

“What would have been the effect of elevated temperatures on the composite floor assemblies?”

Since the floor slabs had a critical role in preventing the exterior walls from buckling, their stability under the conditions encountered is a major question.

Considering the available evidence, It would seem that the floors slabs in the impact/fire zone performed poorly.

This is based on the following:

1. There is clear photographic evidence that major damage to the floor slabs occurred in the areas directly impacted by the aircraft.
   
   
   
2. There is also photographic evidence that as the fires burned, additional areas of the floor slabs collapsed within the structure.
   
   
   
3. There is evidence that the fireproofing applied to the trusses under the slabs was generally in poor condition prior to 9/11.
   
   
   
4. The impact resistance of the type of fireproofing used was low. This is a result of a number of factors, including, poor substrate condition prior to the fireproofing application (i.e. the surface rust and scale was not adequately cleaned off), the lack of any established standards for impact resistance (at the time of installation), and the geometry of the truss itself where the thickness of the applied fireproofing was relatively high compared to the small surface area and small cross sections of the floor truss chords and diagonals. Thus the shock of the airplane impact would have been enough to damage the fireproofing to the point of being useless.
   
   
   
5. The original testing of the floor slab assemblies was conducted on shorter lengths of trusses then those that were actually used in the WTC towers. There is some question as to the validity of how the fire resistance ratings were scaled upward when the longer spans were used.
   
   
   
6. The thin concrete layer (4 inches) of the floor would have heated through relatively quickly. To appreciate how thin the concrete was in relation to the size of the floors, think of it as being close to the size to thickness ratio of a potato chip (a little thinner actually). Concrete spalls when heated, and at 4” thick, it wouldn’t have taken much spalling to severely impact the structural integrity of the slabs.
   
   
   
7. I’ve yet to see anyone give any consideration to the additional weight of the aircraft on the floors. Even broken up, scattered about, and on fire, there was a lot of additional weight on the floors from the plane.
   
   

Originally posted by aggroskater
7.) What else was present in the towers where the planes hit besides steel and jet fuel?

Originally posted by Lumos
7) Offices?

Originally posted by bsbray11

Some paper; plastic. Concrete, asbestos, and Gypsum, I think. People.

An airplane, Carpeting, Office furniture, computers, cubicles, paper (filing cabinets), etc.


source

August 31, 2003 -- The fiery hell that raged inside the World Trade Center on 9/11 has been recreated in a test that highlights how today's office space can be dangerously flammable, as these dramatic pictures show.
Using a cubicle based on the offices of insurance firm Marsh & McLennan - a north tower tenant that lost 295 employees - federal fire experts conclude it was more likely the heat of burning office materials brought down the tower, rather than jet-fuel-fed flames.
This test, conducted by National Institute of Standards and Technology last month, showed the fuel from the plane that crashed into the tower burned out quickly - but the fire it created grew in intensity by up to another 300 degrees as it consumed office products and structures.
The computers, cubicle walls, furniture, files and paper - recreated on detailed information supplied by the insurance company on the exact materials used in their offices - blazed at temperatures that reached 1,200 degrees, the NIST test found.
The test fire burned for 33 minutes before the 386 pounds of material were consumed and reduced mostly to ash and gases.

Originally posted by craig732

Originally posted by Lumos
Craig, if that were true, how do all those nonfatal highrise fires fit in?

I cannot speak for the other buildings, but the Meridian Plaza Building in Philadelphia is constructed of concrete and granite encased steel, and the One New York Plaza building was constructed of concrete encased steel. These buildings were not of the same design as the WTC buildings. Also, fire needs three things to burn: oxygen, fuel, and heat. In normal building fires, the sprinkler systems go a long way to control the spread of the fire by wetting the fuel and keeping the temperatue of the fuel cooler than if it is dry. In the case of the WTC, most of the sprinklers failed due to the sprinkler risers being severed by the initial impacts.

The only info I can find on the 1 New York Plaza is this:

Floor construction. The use of a four inch concrete floor over corrugated steel I beams has failed at every multiple alarm fire in New York City. Floor steel beam supports sag, warp and twist. The four inch concrete floor above sags with the steel cracks and heaves. Smoke and flames spread to the floor above. Floor beams and concrete floor surface must be replaced after every serious fire. This started at the 1970s fire in 1 New York Plaza, where 130 steel floor beams were replaced and 20,000 square feet of concrete floor was removed.

vincentdunn.com...&e/buildings.htm

This implies that the floor construction was a standard I-beam grid system, not the floor trusses used in the WTC towers.

This is the same type of construction that was used in the Meridian Plaza building, and the Los Angeles Bank Building. In addition, the sprayed on fireproofing used in the Los Angeles buildings was noted to have been especially well applied in terms of thickness and coverage. No mob contractor there.

As for the Caracas and Madrid buildings, these were in fact composite structures with different parts built with either concrete or steel framing. In both of these buildings, the steel framed portions did fail.

Originally posted by HowardRoark
Now an interesting thing to consider is this:

We are all familiar with the use of the term watt in relation to energy.

Watts are defined as joules/second.

Thus a 1000 watt fire released 1000 joules per second.

How many watts of energy would be released by 1,000 gallons of jet fuel burning up in 5 minutes?

1,000 gallons of jet fuel = about 3066 kg.

thus the combustion of 1,000 gallons of jet fuel in 5 minutes will release around 437 megawatts of energy.

Worth thinking about.

No, it's not worth thinking about, because most of that energy would be lost in the air and etc. rather than go towards heating the steel. And even what of it did go towards heating steel, that heat would just be conducted throughout the large quantity of beams. Especially when the smoke turned darker, massive proportions of that heat energy were just going right into the air.

In any case. Stating that jet fuel can only burn at such and such temperature is incorrect.

So there have never been any estimates done on what temperatures hydrocarbon fires usually burn at?

Even the temperature of a candle flame can exceed 1000 degrees C.

That's because candles are small and designed to burn. More fire does not mean hotter temperatures, and the materials were less than ideal.

Originally posted by HowardRoark
The melting point of aluminum is 660 Degrees C.

At this corner of the building, the fire apparently got pretty hot.

Well here is why what you are implying is wrong:

The vast amount of aluminum in the building was from perimeter column facades and the aircraft. The aluminum was very thin and therefore conducted heat very poorly.

By contrast, the steel beams were thicker and would have conducted heat much more efficiently to other parts of the structure. Steel is known especially for this characteristic.

And that's why you're not seeing any glowing steel there Howard, despite the melted aluminum.

Originally posted by HowardRoark
The general design is what is called a “framed tube” construction. The WTC towers were not the only structures to use this construction method, but they were one of the first.

The exterior columns were designed to withstand all of the lateral loads and approximately 50 percent of the gravity loads.

The core was not designed to resist lateral loads, but it supported 50 % of the gravity loads.

Credible sources please?

Needless to say, I don't trust you at all.

The designs of the buildings are not classified. Enough information is available for any reasonably competent engineer to understand the structural system. The NIST reports have numerous design documents in the appendices.

This is just flat out bullcrap. NIST is also a very unreliable source, just from the large amounts of b.s. in general that they have put forth and their manner of conducting "research."

The fact, is that the original construction drawings are not being released to the public, despite the fact that they not only exist, but NIST has ready access to them.

How much did each floor weigh? We don't know. How much steel was used in each building? Where was it? Why do FEMA's numbers for steel not add up? Where was the steel that FEMA did not account for? How much did each building weigh even? Yeah, that's right. We don't even know how much either Tower weighed.

Welp, we don't know, because the construction drawings are locked up!

Originally posted by HowardRoark
Trumpman's analysis is fraught with errors.

Such as?

In addition, I have yet to see any indications of his credibility. i.e. is he an engineer?

Why is who is saying something always more important to you than what is actually being said?

Simple answer is because it's easier to mock or discredit someone than to address what they're actually saying.

In any case, the issue here is not all that simple, since you have to try and calculate the affect on the impact and fire damage on the building, and how loads were redistributed as the structural integrity of various portions of the building was compromised.

Trumpman was getting figures for the building, assuming no impacts/fires had occurred. These figures were to show how much each floor could hold with no damage.

From there you can look at how much damage was done by the impacts (less than 15% column severing) and fire (even less going by the fact that none of the steel was heated to above 400 degrees Celsius, or likely even much beyond 250). Doesn't take a rocket scientist to put that info together. Hell, I can do it.

It's pretty simple: the towers could have withstood that.

It's not even close enough to fine tune other variables. It's off by a long shot. No hope that that damage alone could bring the towers down, ever. There would have to be more.

Originally posted by HowardRoark
The NIST report did not show that none of the steel was heated above 250 degrees. It stated that the two pieces of steel recovered from the core region on the impact floors, were not heated above those temperatures.

Damn, Howard! You're just going all out with deception today. Must be all these people suddenly dropping the official line or something.

From the NIST Report (emphasis mine):

Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC (p. 90).

Do you know what that means? They tested much more than just two samples!

But nonetheless, it doesn't matter. None of the steel went much beyond 400 degrees C, because steel starts giving off photons around those temperatures, which means a glow visible in daylight. How many times have I said this now?


And then the floor slabs.... which are completely irrelevant, because the alleged "buckling" is a bunch of b.s., and without that buckling you would have absolutely no case Howard. And you don't have any case. I've posted before showing in detail how the NIST report exaggerates the "buckling" of the aluminum panels.

But I really liked this, nonetheless..

There is clear photographic evidence that major damage to the floor slabs occurred in the areas directly impacted by the aircraft.

You got me. I would never in a million years have expected this.

There is evidence that the fireproofing applied to the trusses under the slabs was generally in poor condition prior to 9/11.

Irrelevant because bare naked steel could've easily withstood the heat within those buildings. And it did.

And the rest of your post's points are similarly based upon notions of non-existant buckling and major damage from fire.

Originally posted by bsbray11

Originally posted by HowardRoark
The NIST report did not show that none of the steel was heated above 250 degrees. It stated that the two pieces of steel recovered from the core region on the impact floors, were not heated above those temperatures.

Damn, Howard! You're just going all out with deception today. Must be all these people suddenly dropping the official line or something.

From the NIST Report (emphasis mine):

Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC (p. 90).

Do you know what that means? They tested much more than just two samples!

No, it means that only two had enough paint left on them to indicate that the temperature did not exceed 250. I wonder what happened to the paint on the other samples? Maybe it burned off?