Witnesses Corroborating Rodriguez's Claims?

[brasil]

Sophomore level enginnering has a class callled Statics. In it, you learn to draw free body diagrams of systems and equilibriate force. If I hold a stick, apply a force at one end, my free body diagram requires the ground to apply an equal and opposite direction force to balance it. Also a moment. This is whether the stick bends or not.

I apologize that I cannot quote the Statics book that this is from but it is in EVERY book on Statics.

So we would expect the ground to see force in oppostion to the plane impact.

I have not taken a "statics" class, although my father (the structural engineer) most certainly has. Next time I talk to him maybe i'll ask. However, very basic understanding of newtons laws should be enough to cause me to have questions about the seismic data. Witnesses in the buildings reported that the towers swayed back and forth to such an extent that they thought the buildings might "topple over." The buildings were designed to be flexible enough to be able to absorb the energy of very strong winds. When strong winds caused the towers to sway back and forth, did that also cause smaller, yet still measurable seismic effects? If this energy is so efficiently being transferred to the ground you would think they would.

My admittedly limited understanding of the physics involved still tells me that the majority of the energy from the impacts was absorbed by the back and forth motion of the buildings, not the ground. If the buildings truly were "static" and did not move at all, then perhaps all or most of the energy would have transmitted to the ground, but they were not. How much energy do you suppose it would take to cause the top of the tower to sway a few feet in either direction a few times?

Did my Columbia colleagues address the physics of the planes hitting buildings, or simply state that nothing about their data makes them conclude that explosives were used, but also that explosives were not used? I don't think they know for sure, and just want to make sure no one believes they're arguing for explosives when they themselves don't know the answer.

 

[beachnut]

reading it now.... looks interesting.

I do not consider 10,000 gallons of jet fuel at 700 feet above me to be 1000 feet away! I consider the 10,000 gallons of jet fuel and jet parts, and other damaged stuff to be real close to me soon (this is why some of that voodoo math stuff comes in handy when you work with g). You must get a handle on up and down, and left and right. You truthers always forget gravity and have zero idea on structures and impacts. Poor brazil is way too smart to be posting here; he needs to feel better and post at the high IQ LCF! Sorry, but you did say you were very well informed on 9/11 stuff, but you are still reading?

 

[R.Mackey]

R.Mackey:

"On what basis do you claim that the jet fuel vapor would "take time" to fill a room, time enough for people in the room to detect it and evacuate?"

On the basis that the state of the jet fuel when it reached the basement was either a) already burning or b) in liquid form. If it was already burning, then vapor is out of the question. If it was in liquid form, it would take quite a bit of time to evaporate into enough vapor to fill the room and then ignite.

You have no reason whatsoever to assume the jet fuel was either "already burning" or "in liquid form." The overwhelming majority of jet fuel -- in the seconds after crashing into a fixed, steel structure at cruising speed! -- would have been dashed to small droplets. Any large flows that remained would have been further aereated during its several hundred foot fall to the basement. Your premise is absurd!

Well aereated jet fuel can and does explode. The jet fuel that made it to the basement was well aerated, and even heated by the friction of impact and the fireballs above. We also know for a fact that the majority of jet fuel was not contained in the initial fireball -- there isn't enough oxygen in the first tenth of a second -- so it's not necessarily "on fire" either. There are plenty of points of ignition, but not all of the fuel was "on fire." Only a small fraction of it.

Very, very simple.

"The jet fuel impacted the structure at either 450+ or 550+ MPH, depending on which structure we're talking about, and poured straight down several hundred feet of elevator shaft. The jet fuel/air mix thus created would have been heated but not all burned due to the fireball at impact, which briefly created an oxygen-poor environment on the upper floors. Falling elevators in those same shafts could even have created negative pressure in those shafts, sucking the fuel/air mix along with them."

Do we really know for sure what state the jet fuel was in when it made its way down the elevator shaft? From the video of the second impact, we can see that a majority of the jet fuel exploded outside the building, and yet, Philip Morelli describes virtually identical conditions in the basement of WTC2 as he had just experienced in WTC1.

Yes. It was a mixture of liquid and vapor. Most of the liquid was in drops, not large pools. Some was absorbed by furniture and other porous surfaces. Some would collect into pools over time. But there's so much fuel around -- about 24,000 pounds of it, in each tower -- that there's an overwhelming surplus of jet fuel in all states, ready to explode and ready to burn. That's why we saw both effects in both towers.

If I understand correctly, you're saying that an "elevator/fuel/air" mixture fell at great speed from the tops of the building and did not ignite until it had reached the base of the building, creating blast effects on 3 or 4 floors, from the lobby down to the sub-basements. You are also saying that this fuel/air mixture survived the sparks and heat we would expect of an elevator falling that fast, and managed to fill whole basement areas with vapor, and only then ignite? Also, how did this liquid jet fuel get a chance to evenly mix with air in the shafts? Wouldn't it have just dripped down the same way as if you poured water down the shaft? From watching youtube videos of the military's fuel/air explosives in action, it seems to be a pretty tricky process to combine the fuel and air to the point that it becomes explosive. I don't see any such conditions in the elevator shafts.

Strawman city. The initial fuel/air mixture was oxygen depleted, and could not all burn at once. As it progressed downward, it mixed with fresh air. It doesn't, of course, have to "mix evenly." If it had, the resulting explosion would have been enormous, probably enough to destroy the Tower right then and there, as I explained in the other thread.

Yes, there probably was some fuel dripping down. But that aereates it as well. If you drip fuel several hundred feet onto a hard surface, like, oh, the rails or bottom of an elevator shaft, it will splash and aerate quite nicely on contact.

We don't require "even mixing" and we don't require a precise fuel/air ratio. There is a range of fuel/air ratios for which jet fuel can deflagrate. Areas of the mixture that were in this ratio and found a source of ignition would deflagrate. Areas that weren't would either dissipate (if too fuel-poor), ignite and burn (if too fuel-rich) or possibly deflagrate later (also if too fuel-rich). But there's so much jet fuel in play -- and our energy requirements are so reasonable -- that we don't need it all to deflagrate at once. We only need, at worst, about 1% of it in the basement. With a more careful estimate, perhaps only 0.1% must deflagrate to create the destruction in the basement.

It's completely reasonable no matter how you look at it.

"Conditions are perfect for a backdraft situation, in the basement, a few seconds to a few tens of seconds after impact. I have no idea how anyone could conclude otherwise."

I am not concluding that backdraft is not a possibility, I'm hypothesizing that backdraft and the other conditions mentioned are not sufficient to create blast effects from the lobby to the basements, and almost identically (according to Philip Morelli) in both towers, despite very different impact scenarios.

So far you've offered no support for that hypothesis at all. Everything about the event checks: The size and degree of the damage area, people burned but not concussed, the timing, reports of fireballs, absolutely everything. Your burden of proof is rather high.

I need to learn more about backdraft and how it applies to exploding jet fuel almost 1000 ft. above the area we are told was affected. Has backdraft ever been known to create effects at such a distance in the history of firefighting? I'm going to read up on backdraft, but I want to hear your thoughts (DGM and R.Mackey).

We happen to have an almost ideal example of historical precedent -- the B-25 vs. Empire State Building episode. In this accident, deflagrations occurred about five floors away from the impact and six seconds later, and in this case the fuel path was impeded by stairs rather than falling straight through one or more open elevator shafts.

Given that the B-25 carried about twenty times less fuel, maximum, and the one that hit the Empire State Building was landing and probably well below its maximum capacity, it's not surprising in the least that the WTC impacts would flow fuel for a greater distance. Particularly when channeled into elevator shafts.

 

[ElMondoHummus]

My admittedly limited understanding of the physics involved still tells me that the majority of the energy from the impacts was absorbed by the back and forth motion of the buildings, not the ground. If the buildings truly were "static" and did not move at all, then perhaps all or most of the energy would have transmitted to the ground, but they were not. How much energy do you suppose it would take to cause the top of the tower to sway a few feet in either direction a few times?

I think this was addressed by Frank Greening (please correct me if I'm misremembering this!) and discussed by other engineers in this forum here. I'll try to find the posts when I get a chance.

But, in all due respect, it may be a leap to a conclusion to assume that "the majority of the energy from the impacts was absorbed by the back and forth motion of the buildings, not the ground". It's possible that it wasn't the "majority of the energy from the impacts", but merely a fraction smaller than that.

Again, I'll try to find the relevant posts when I can. Or, if anyone here remembers them, they can chime in too.

Anyway, bottom line is: That's a quantitative claim without any numbers accompanying it. Is there any chance you can get more specific as to why you believe that building sway absorbed most of the impact energy? Also: That point has been addressed before. If you have the time, you can do a search for those posts and see what has been said before. That might help advance the discussion to firmer grounds.

 

[ElMondoHummus]

Whoops! Brasil, ignore my posts temporarily in favor of R. Mackey's. He addresses the jet fuel - explosion issue in detail. Much more important than what I had to say.

 

[R.Mackey]

I think this was addressed by Frank Greening (please correct me if I'm misremembering this!) and discussed by other engineers in this forum here. I'll try to find the posts when I get a chance.

But, in all due respect, it may be a leap to a conclusion to assume that "the majority of the energy from the impacts was absorbed by the back and forth motion of the buildings, not the ground". It's possible that it wasn't the "majority of the energy from the impacts", but merely a fraction smaller than that.

The discussion began here, with Dr. Greening providing several historical examples. Poster Gregory Urich actually argued that too little energy was transmitted seismically by the collapses. I don't agree -- but it's still up for debate.

We didn't explicitly talk about the seismic signals from the impacts, but we can do an energy comparision between impact and collapse to scale this argument to fit. If you do so, you will find that the energy transmission is quite reasonable and in-line with other seismic events related to construction and things like mining accidents.

Also, again, it is not energy that seismographs detect, but displacement. A seismic wave is not necessarily all that dissipative, so a relatively small event (in terms of energy) can be measured (in terms of displacement). There is no energy shortage.

ETA: I had misremembered the course of the discussion. I have corrected who took what position, but you should go read it for yourself.

 

[GregoryUrich]

1. brasil has indicated he knows the 50 tonnes does not refer to the weight.


2. brasil: making an assumption based on what you believe should or should not have happened, while being your right, does not carry much weight here. If you have some science for this particular scenario to show us, that makes the fireball an extremely unlikely candidate to cause the destruction described, now would be a good time to present it.

TAM

Regarding 2, do you have any science showing that a fireball could cause the observed damage?

 

[ElMondoHummus]

The discussion began here, with Dr. Greening providing several historical examples. Poster Gregory Urich actually argued that too little energy was transmitted seismically by the collapses. I don't agree -- but it's still up for debate.

We didn't explicitly talk about the seismic signals from the impacts, but we can do an energy comparision between impact and collapse to scale this argument to fit. If you do so, you will find that the energy transmission is quite reasonable and in-line with other seismic events related to construction and things like mining accidents.

Also, again, it is not energy that seismographs detect, but displacement. A seismic wave is not necessarily all that dissipative, so a relatively small event (in terms of energy) can be measured (in terms of displacement). There is no energy shortage.

ETA: I had misremembered the course of the discussion. I have corrected who took what position, but you should go read it for yourself.

Yes, thank you Mackey. A search has also revealed it to have been discussed here:

http://www.internationalskeptics.com/forums/showthread.php?t=85531

... although as merely one of the many points touched in that thread (as in most threads, there's serious meandering of the topics so some work is required to get at posts specific to a given subject).

Anyway, this can be put aside. Again, Mr. Mackey's post on the fuel is of some substance, and worthy of discussion in regards to what Brasil wrote about its ability to cause the damage. Brasil: Would you mind addressing the points in his post?

Thank you.

 

[Lurker]

Math is an abstraction used to back up observation in the real world. No amount of math can justify a violation of the laws of physics. If you don't have a proper reply to my, or others' questions, don't post.

But you have not shown a cntradiction between math and physics, have you? Did I miss something? The closest I have seen is you proving an opinion that the fireball could not obliterate the press.

 

[T.A.M.]

Gregory:

Fireball is such a vague term. How big was the fireball? Was it in a confined space, and then blasted out, or was it in a wide open space? What type of damage are you looking for an explanation for? The burns to the people nearby? The marble in the lobby? the press? Other?

See all of these variables would be important, but I am not a physicist, and engineer, or a fire/demolition expert. The difference here is, I DO NOT EXPECT MY OPINION ON THIS PARTICULAR MATTER, to matter much, as I am not arguing (I was making comment), where as brasil was trying to prove a point, so he should have a little something more than "what he thinks should have happened" if he expects to win the argument.

but thanks for inquiring.

TAM

 

[T.A.M.]

it works like this Greg:

Respected authorities in these matters (Fire Protection Engineers, the NIST scientists, the FEMA scientists, etc...) have explained what happened as being the result of a fireball that travelled down the elevator shaft.

Now I have no reason to doubt them, and they certainly know better than me.

So if someone is going to come here and argue that the "fireball down the elevator shaft" CANNOT EXPLAIN what happened, then one would expect to have a scientific explanation backing up this view, if they are to convince anyone the experts are wrong...

Sound reasonable?

TAM

 

[R.Mackey]

Gregory:

Fireball is such a vague term. How big was the fireball? Was it in a confined space, and then blasted out, or was it in a wide open space? What type of damage are you looking for an explanation for? The burns to the people nearby? The marble in the lobby? the press? Other?

T.A.M. and Gregory: You probably haven't seen it, but I computed rigorously that jet fuel is way more than adequate for the task in this post, my Point 3. about halfway through it.

 

[brasil]

So far you've offered no support for that hypothesis at all. Everything about the event checks: The size and degree of the damage area, people burned but not concussed, the timing, reports of fireballs, absolutely everything. Your burden of proof is rather high.

I'm not at the "find support for my hypothesis" stage yet. I'm still refining it based on the (few) intelligent, on-topic replies I'm getting. I disagree, in theory, on so many of your points, but my next reply to you will be more researched. So far I'm just thinking it through for myself - imagine that.

The point I most strongly disagree with is your idea that it's so simple and such a "given" that un-ignited jet fuel could go from:

1) inside the wings, in liquid form
2) smashing against the steel frame of the building
3) passing through multiple floors of the tower,most of it on fire, with a majority exiting the building in the case of WTC2
4) breaking through the core near the elevator shafts
5) falling hundreds of feet on top of elevators
6) getting past the elevators, now in a conveniently mixed "fuel/air" state

to: igniting and exploding with such force that it caused clear blast effects in the lobby (as seen in the fireman's video) and clear descriptions of blast effects on 2, 3, or even 4 sub-basement floors.

You say:

"You have no reason whatsoever to assume the jet fuel was either "already burning" or "in liquid form." The overwhelming majority of jet fuel -- in the seconds after crashing into a fixed, steel structure at cruising speed! -- would have been dashed to small droplets."

I have every reason to believe it was already burning (and less reason to believe it was in liquid form). The videos clearly show massive, fiery explosions, with flames shooting out the sides of the buildings! If I remember correctly, the NIST report assumes massive fireballs passing across the impact floors. If that's not a reason to assume that it's "already burning" then I don't know what is. I think is it you who has no reason whatsoever to assume that the fuel was in a state after impact for large quantities of it to find it's way to the basement in an un-ignited state.

Secondly, you are saying that in the seconds after the impact the fuel "would have been dashed to small droplets." Isn't a mass of jet fuel in the form of "small droplets," mixed with the air, in the perfect fuel/air state you are saying is ripe to explode? With all of that fire around from the impact, how would this cloud of "small droplets" find it's way down the elevator shafts to the basement? It seems if it's in "cloud" or "mist" form, it's not likely to suddenly head for the basement. Seems it's in a perfect state to just explode right then and there.

This is why I thought the only possible form it could be in to make it all the way down those shafts is liquid form. Now you're saying it had to be in small droplet form, and I tend to agree with that for the most part, but if that's true, then how did it get to the basement? Please explain while I take some time to reply to your other points.

 

[Alferd_Packer]

Ok, it's possible that it tipped over if it was that kind of press. The photo of the press I posted could have been what it looked like, and that one definitely looks like it's not the kind that tips over. Pecoraro seemed genuinely shocked that his press was nowhere to be seen, but it sounds like you wouldn't be if it was the kind you have. The one I linked to is here (looks pretty old):

http://www.cincinnatiprecisionmachi.../used30tonhydraulicpress_SandSMachine (2).jpg

This is what happens when some one has limited experience with how things work in the real world, especially that of building maintenance.

Why would they have a specialty press for bending sheet metal in the basement of the WTC towers? A very expensive piece of equipment that has to be run constantly in order to repay the capital investment in it.

What they would have had was a simple, low cost press like this,

which is very handy in a building maintenance shop for replacing motor bearings.

 

[Lurker]

I have not taken a "statics" class, although my father (the structural engineer) most certainly has. Next time I talk to him maybe i'll ask. However, very basic understanding of newtons laws should be enough to cause me to have questions about the seismic data. Witnesses in the buildings reported that the towers swayed back and forth to such an extent that they thought the buildings might "topple over." The buildings were designed to be flexible enough to be able to absorb the energy of very strong winds. When strong winds caused the towers to sway back and forth, did that also cause smaller, yet still measurable seismic effects? If this energy is so efficiently being transferred to the ground you would think they would.

I would imagine that the force causing the swaying would be transmitted to the ground.

My admittedly limited understanding of the physics involved still tells me that the majority of the energy from the impacts was absorbed by the back and forth motion of the buildings, not the ground. If the buildings truly were "static" and did not move at all, then perhaps all or most of the energy would have transmitted to the ground, but they were not. How much energy do you suppose it would take to cause the top of the tower to sway a few feet in either direction a few times?

Careful, you are mixing energy and force here. Whether the bldg was static or not, the force balance would be the same, even with a impact wave going down the structure.

 

[GregoryUrich]

On what basis do you claim that the jet fuel vapor would "take time" to fill a room, time enough for people in the room to detect it and evacuate?

The jet fuel impacted the structure at either 450+ or 550+ MPH, depending on which structure we're talking about, and poured straight down several hundred feet of elevator shaft. The jet fuel/air mix thus created would have been heated but not all burned due to the fireball at impact, which briefly created an oxygen-poor environment on the upper floors. Falling elevators in those same shafts could even have created negative pressure in those shafts, sucking the fuel/air mix along with them.

Conditions are perfect for a backdraft situation, in the basement, a few seconds to a few tens of seconds after impact. I have no idea how anyone could conclude otherwise.

Freefall from the impact zone to the basement (of WTC 1 anyway) is around 8 seconds so anything less than that is not realistic. For a runaway elevator though, the resistance due to air pressure will be considerable in a closed shaft. Also due the over-pressure on the underside of the elevator, compressed air will be rushing out of the spaces between the elevator and the shaft walls, which will minimize the ability of the elevator to pull the fuel/air mix after it.

I don't think it's realistic to think of this as a fuel-air explosion in terms of fuel-air bombs which have much better means of dispersion. I think fireball is a more apt term.

 

[brasil]

T.A.M. and Gregory: You probably haven't seen it, but I computed rigorously that jet fuel is way more than adequate for the task in this post, my Point 3. about halfway through it.

As you know, I read that post, and if your stats for MJ/kg of jet fuel as compared to TNT are correct, then I can believe the energy potential is present in jet fuel, however, the point I continue to drive home is that for that energy to be released from the jet fuel in such a way as to cause a blast (meaning, something with a real shockwave capable of knocking down walls, blowing out windows, and even toppling or destroying a press, on multiple floors of a concrete and steel building), it has to be in a very specific state, namely the "fuel/air" mix we keep referring to. To get from liquid in the wings to "fuel/air vapor" in the basement is a huge stretch of the imagination, IMO. Burning fireballs shooting down the elevators: likely. Fuel/air mist traveling that far and then exploding in the basement: not likely at all.

 

[T.A.M.]

T.A.M. and Gregory: You probably haven't seen it, but I computed rigorously that jet fuel is way more than adequate for the task in this post, my Point 3. about halfway through it.

Thanks Mackey, I did miss it, but have since read it.

TAM

 

[R.Mackey]

I'm not at the "find support for my hypothesis" stage yet. I'm still refining it based on the (few) intelligent, on-topic replies I'm getting. I disagree, in theory, on so many of your points, but my next reply to you will be more researched. So far I'm just thinking it through for myself - imagine that.

Your assertions are far too strongly worded for one who is merely "thinking it through." Nevertheless, take all the time you need.

The point I most strongly disagree with is your idea that it's so simple and such a "given" that un-ignited jet fuel could go from:

1) inside the wings, in liquid form
2) smashing against the steel frame of the building
3) passing through multiple floors of the tower,most of it on fire, with a majority exiting the building in the case of WTC2
4) breaking through the core near the elevator shafts
5) falling hundreds of feet on top of elevators
6) getting past the elevators, now in a conveniently mixed "fuel/air" state

The portions I have bolded are strawman arguments. To wit:

3) "Most of it" was not on fire. See below.
4) The aircraft structure and fracture would also contribute to opening the elevator shafts. Fuel doesn't have to do that by itself, even though NIST suggests that it easily could.
5) It could fall on top of elevators, flow down as a vapor or mist behind the elevators, or run down the sides. Probably all of the above.
6) There is no requirement to "get past the elevators." We do not have a precise spot where ignition began, and it was a large volumetric event.

Correcting these errors, I see nothing particularly remarkable about this hypothesis.

to: igniting and exploding with such force that it caused clear blast effects in the lobby (as seen in the fireman's video) and clear descriptions of blast effects on 2, 3, or even 4 sub-basement floors.

I've already demonstrated, rigorously, that the amount of fuel required to do this is quite modest.

"You have no reason whatsoever to assume the jet fuel was either "already burning" or "in liquid form." The overwhelming majority of jet fuel -- in the seconds after crashing into a fixed, steel structure at cruising speed! -- would have been dashed to small droplets."

I have every reason to believe it was already burning (and less reason to believe it was in liquid form). The videos clearly show massive, fiery explosions, with flames shooting out the sides of the buildings! If I remember correctly, the NIST report assumes massive fireballs passing across the impact floors. If that's not a reason to assume that it's "already burning" then I don't know what is. I think is it you who has no reason whatsoever to assume that the fuel was in a state after impact for large quantities of it to find it's way to the basement in an un-ignited state.

No. NIST explains -- and you can calculate for yourself, using an estimate of the fireball size -- that there simply wasn't enough oxygen to combust or even ignite all the fuel at once. I've already explained this to you. I'm not sure explaining it again will do any good at this point.

NIST estimated that only 20% of the fuel was consumed in the initial fireball. It's a rough estimate, but it's probably good to +/- 10%. That leaves a vast quantity of fuel, all of it locally oxygen starved, all still traveling at high velocity...

Secondly, you are saying that in the seconds after the impact the fuel "would have been dashed to small droplets." Isn't a mass of jet fuel in the form of "small droplets," mixed with the air, in the perfect fuel/air state you are saying is ripe to explode? With all of that fire around from the impact, how would this cloud of "small droplets" find it's way down the elevator shafts to the basement? It seems if it's in "cloud" or "mist" form, it's not likely to suddenly head for the basement. Seems it's in a perfect state to just explode right then and there.

There were other fireballs observed. I'd have to go back to NCSTAR1-7 to check, but there were fireballs observed on I think the 45^th floor of WTC1, but no fireballs seen on several floors above and below. Local conditions will dictate where and how much fuel ignites, and whether it deflagrates or merely burns. Nothing unusual about this at all.

This is why I thought the only possible form it could be in to make it all the way down those shafts is liquid form. Now you're saying it had to be in small droplet form, and I tend to agree with that for the most part, but if that's true, then how did it get to the basement? Please explain while I take some time to reply to your other points.

Down the elevator shafts. I've already explained this too. Mist, drops, streams, pools, whatever -- the fuel can fall down, get sucked down by the elevators, get blown down by the pressure wave above, take your pick. Fuel that enters the shaft as liquid will aereate as it falls. Fuel that enters as entrained mist is already aereated. Fuel that enters as partially combusted, oxygen-starved heated vapor will self-ignite after ingesting the correct amount of fresh air, and this could happen anywhere along the way depending on its density.

I'm still baffled about why this scenario even seems implausible. Crash a fuel-laden jetliner into a building, and you're going to get fireballs. Not just one, either. This seems absolutely trivial to grasp.

 

[R.Mackey]

Freefall from the impact zone to the basement (of WTC 1 anyway) is around 8 seconds so anything less than that is not realistic. For a runaway elevator though, the resistance due to air pressure will be considerable in a closed shaft. Also due the over-pressure on the underside of the elevator, compressed air will be rushing out of the spaces between the elevator and the shaft walls, which will minimize the ability of the elevator to pull the fuel/air mix after it.

About eight seconds is what I expect. There's no evidence of a fireball occurring faster than this. William Rodriguez's account speaks of a fireball some seconds after extricating two survivors from the freight elevator, so perhaps 15 seconds or even more.

The pressure situation in the elevator shafts will be complicated -- but the falling elevator will entrain vapors, even if the shaft is hermetically sealed, and there's no reason to suppose it was.

I don't think it's realistic to think of this as a fuel-air explosion in terms of fuel-air bombs which have much better means of dispersion. I think fireball is a more apt term.

I agree. This is why we speak of deflagration rather than detonation. The phenomenology in the basement is not a good fit to an optimized FAE.