What happened to the reinforcing steel

[screembloodymurder]

The towers were heavily reinforced. The concrete turned to dust. The debris should have looked like a pile of spaghetti. Was anyone here, there? Did you see piles of tangled steel bars?

[boastOne43]

1. Look at this photo

Here you go. But the most interesting image in this photo is the column directly above the fireman's helmet. It shows that it was cut with thermite. There is a substantial amount of hardened molten iron which can be seen on both the inside and outside of the box column. This is precisely what one would expect to find on a column which had been cut with thermite.

Experts who have viewed this photograph say that this column was not cut with a torch.

[Jazz2006]

2. Link?

Backup?

Evidence?

[boastOne43]

3. link...

http://www.physics.byu.edu/research/energy/htm7.html

[Jazz2006]

5. Oh....

Steven Jones.

You can find hundreds of threads and thousands of posts here about him and his work.

Carry on.

(no offence intended but any so called scholar who writes about (and believes) stories about Christ visiting America and cold fusion just doesn't strike me as terribly credible to begin with, and then when the university he works at expressly disabuses itself of this particular paper and the physics department of the university expressly disagrees with his conclusions in this particular paper, well... )

Oh, and welcome to DU.

:hi:

[petgoat]

7. Try refuting Dr. Jones's argument and eschewing ad hominems nt

[New Earth]

44. like you ever provide any of those....

[jschurchin]

4. Whomever cut that column..........

IF they used a torch did not know what they where doing.

[mirandapriestly]

10. Photo of steel getting cut by torch at ground zero

There's a cut on the twisted arm he's working on where it meets the beam, too.


another, you can see what the cut will look like:


Those were obviously done after the towers fell, but as far as cutting steel for demolition
Dr Jones believes that thermite was placed in a cutting charge, I assume he means a linear shaped charge by this. Does anyone know differently? LSCharges are the most commonly used charges for cutting steel from what I could find. Thermite would be added along with explosives to a shaped charge and this creates a high velocity jet that creates the hole or incision. Those jets (or squibs) seen coming out of the towers would be the end product of this. Here is a cut by a linear shaped charge that does not go all the way through, but it's the only picture I can find of this type of cut on steel.


Discussion with pictures on the different types of shaped charges and the holes or cuts they make:
http://www.sciencemadness.org/talk/viewthread.php?tid=2219

Here is a brief animation on the way a shaped charge works.
http://uwolni.net/photos/filkimi/shaped-charge.mpg

I'm trying to figure this out myself so correct me nicely if I'm wrong, please.

[jschurchin]

11. Can Thermite be used in a shaped charge?

It's an honest question, as I do not know. I always thought shaped charges where MDX or some other type of high explosive.

[Poll_Blind]

18. Yes and no:

A shaped charge, simply put, is a cone of copper surrounded by high-explosives. When the explosives detonate, they squeeze the copper cone into a thin stream of molten copper moving very, very quickly and with great force.

You could place other material in the copper, making something like a colloid (think crunchy peanut butter, thermite being the nuts). However once the high explosives detonated I believe this would interfere with the forces behind the creation of the stream of copper, the thermite "nuts" providing less/more resistance than the copper and hindering the proper transformation of cone to beam.

Hope that helps. Someone could maybe do it but I wouldn't want to be the one to fire it.

PB

[jschurchin]

22. Thanks PB.

I always wondered if it could be a viable possibility.

[mirandapriestly]

24. Here is an example of a shaped charge & thermite

on a really technical site. It is over my head, but it is possible, these guys have developed a lot of devices that we probably don't know about. Excerpt:
"The charge is placed and detonated in the same way as an explosive charge and is self-sustaining once it is initiated (figure 2-10). This technique requires highly efficient thermite mixtures and automated systems to produce linear cuts"

http://www.nap.edu/books/NI000141/html/16.html

If you don't use thermite with shaped charges then what would Jones mean by "cutter charge"?.
Also doesn't the kind of charge you are giving an example of create a round hole rather than a straight cut like a linear shaped charge would do?

[Christophera]

31. Thermite Replaced HE Where Shaping Is Needed-Thermite Needs Contact Only

Thermite made steel demolitions much safer. Cutting steel with high explosives above ground is the most dangerous thing you can do with HE (high explosives). Large over loads are needed without tamping (crude shaping masses). Modern shape charges where high tech relectors are used made explosive shearing into an art.

Jones refers to the special floors of the tower, built to explode and also cut the columns with an extreme shape shage built into the floor. I recall from that documentary I saw in 1990 that there were special, tight fitting plates in the corners of the floor panels where the interior box columns surrounding the core were.

http://algoxy.com/psych/9-11scenario.html#anchor1233383

[mirandapriestly]

46. What do you think was done about the perimeter columns?

and what do you think the jets (some call squibs) that shoot out from the towers are? Do you think they are from the detonations at floor level ?
I think I mentioned this to you before, but when I was checking out books from the library on 9-11 and the wtc, I found a few (very few) that were pre 2001, one of them mentioned a lawsuit in either '85 or '95 of people trying to get information on certain aspects of the construction of the wtc and this information was denied them. I didn't think much of it at the time, but I can see why now.

[Christophera]

50. Yes, Horizontal Blasts Are Floors Detonating. Spandrel Plate Blocks Direct

spray of dust but horizontal row in array shows it is floor.



Note the spire of perimeter box columns. This shows that some of the encapsulated high explosive built into the floors did not detonate. The interior box column behind that segment of perimeter wall did not get cut, then when the core went off behind it it did not lever outward to break of the chunk of perimeter wall.

The suit was probably in 95'.

The perimeter columns were butt bolted and bolted together at the sides where spandrels connected with a lap plate. Pretty much totally designed for compression loads. When the floors blew, the perimeters were certainly loosened and the interior box columns against the outside of the concrete core wall were cut. After that the core detonated in 40 foot sections which tilted, pushing outward on the 1 x3 foot floor beams rolling/heaving the perimeter columns outward. Below is an interior box column intersection with floor beams. Note the crumpled beam (lower left to top right) from extreme compression loads. Note beams the other direction (along core face) are not crumpled.



Below is the rolling action of the series of cut interior box columns outward. Perimeter columns have already fallen and are obscured by the interior box columns and the concrete debris that pushed them outward.

[Christophera]

37. Floors Built With Cutter Charges. Explosive Shear - Thermite in the

Basement.

Here are the results of explosive shear on the left and a torch cut on the right.




Here is how column cutting floors were constructed.

[Lithos]

6. It was cut after the collapse

After the building had fallen probably to allow for greater access to other portions of the rubble. Note the angle of the column and the slag which flowed according to the geometry of the photo. This includes the transverse cut thru the metal (thermite would have cut a chamfer as it worked from outside to inside) as well as the flow down the web, something which would NOT have happened if "thermite" or some other agent were used.

L-

[petgoat]

8. It looks to me like the cuts ARE chamfered.

Look at that knife edge on the forward face.

The partially done cut would have formed a gutter, bringing
the molten metal to dribble down the forward face.

Also, I don't understand the angle cut if done by a torch. Presumably
toppling the column like a tree would have been too dangerous. If they
held the column up with a crane while cutting it, why cut the long angle
when they could just cut straight across?

The angle cut makes sense in the context of demolition because it would
tend to slide the top of the building off the lower part.

[dailykoff]

9. Here's another problem:

the columns in the photo are still as straight as arrows. No buckling, no bending, no twisting.

So if they weren't cut, what are they doing on the ground?

[Jazz2006]

14. shhhhhhh

#4 seems to show not-so-straight beams.

Keep it to yourself. That doesn't quite fit with the conspiracy theory, after all.

The photos also make a bit of a mockery of other posts on other threads about the steel conveniently falling in nice, neat 'manageable lengths", don't you think?

Ooops. Shhhhh. Again.

[dailykoff]

17. I said columns, not beams. (n/t)

[Jazz2006]

19. See photo #1 in post #10 n/t

[dailykoff]

26. The column is straight. The beams are bent.

That's the point.

p.s. ditto the photo below as far as I can tell.

[Christophera]

62. Beams Absorbed Exploding Concrete Core Wall, MAX. Compression Failure

The beams to the bottom left went to the core face and other "I" beams fastened to it. To the top right the beams ran out to the perimeter walls.



The intersection of floor beams and interior box column is from upper elevations of the tower because it is square, (lower interior box columns were rectangular, heavier) and it is extruded.

Note the 100% butt weld about 1 foot right of the intersection on the square tube. The discolored or different textured area has been ground off after welding. We see it on 2 faces ground about 3-4 inches wide. That covers about a 1 inch thick butt fillet weld nicely. Also, it must be from the north tower as it had a tapered concrete core which made the 4 direction intersection needed. If the concrete face is not separate from the plumb column, why do you need a 4th horizontal member? You do not. We see four directions because near the top of the tower the concrete face was about 12 feet from t the plumb column.

Note the second bright line inside of the tower perimeter of WTC 1 on the right. The light passing through that space between the column and the core. Note the barely perceptable taper to that line. The core was thicker as it went down.

[LARED]

16. The long angle

is there to assist is molten metal removal via gravity. Cutting is done at an angle so the molten metal runs out rather than just sitting in the hole to fuse together again after heat is removed. Particularly true if one uses a carbon arc cutting method.

Also it seem to me that cutting the bottom of the columns flies in the face of all video evidence. The towers collapse from the top down. Unless you believe thermite cutting of metal can be synchronized to a few milliseconds

[petgoat]

20. The long angle

Then why are the top and bottom cuts level instead of chevron-shaped?

I don't see how the fact that the towers collapsed from the top down contradicts the possibility
that the core columns were cut by thermite at the base. The vertical descent of the TV tower
is cited by some as evidence that on the north tower the core failed first.

I also don't see the justification for your belief that use of thermite at the base requires
millisecond synchronization. If the bottom didn't collapse until fifteen seconds later,
why impose impossible standards?

[Christophera]

32. Cut At Angle Formed HORIZ. Hinge For Grapple To Break Off Piece.

Note the top left and bottom left corners of the cut. The top left was what held the piece from toppling towards us, the bottom kept it at rest, prevented tilting. An hydraulic excavator equipped with a rotating grapple probably held the piece near the end of the cut in case it tipped, perhaps not tho and may have come along afterwards and grabbed the column up high from the left side as we see it. As it pulled towards itself, away from us, and rotated its turntable, the top left piece snapped off (tempered steel) and the bottom left corner, the rest tore away as the piece swung away from the elevator pit, hinging on the remaining uncut areas until they snapped and the excavator had full control of the piece.

[petgoat]

33. Yeah, I noticed that unburnt part at top, and wondered what

that biscuit at the bottom was. That makes sense.

[Christophera]

38. Found The Pic Of The Long Torch Used To Cut From Backside Of Column

Mirandapriestly posted this image and I saw the torch handle in use that I described.



Did you see this other post where I describe the hinge?

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=83573&mesg_id=83815

[Christophera]

64. Excavator W/Rotating Grapple-Single Point Not Cut Is Pivot/Hinge

Thick metal means the oxygen jet is not so sharp 4 inches away from the tip. The jet blurs outward involving more metal and then curves inward making less outlet for molten metal. The outlet gets easily choked in situation where the operator does not have optimum control meaning to far edges of the cut will billow out before metal almost cooling builds up on the outlet edges. Probably one of the most difficult cuts to do, particuarly with the long straight handled scrapping torch



working through a small hole in the back of the column. The bottom half of the hole can be seen in the top, back cut of the column.

The bottom left corner is the pivot point. The welder cuts the hole in the back, then the bottom cut leaving the left corner, the sides (wedges are installed in the kerf) then cuts the back.



Think about it, the column cannot fall to him when he leaves the connection point in the left front. The piece can only fall away. There is probably another small point where it is not cut all the way through.

A 40 ton excavator with a rotating grapple must position itself, minimally extended, so that the weight of the column does not tip it before the column can be brought to the ground under control to gain optimum bite. By loosening the grapple grip and rotating the turn table while perhaps travelling for a foot or 2 with the tracks, the column can be tilted to horizontal partially and it will do this while coming towards the machine because of the angled cut; meaning that the chances of loosing the piece into the hole are less before it can be brought to the ground and the grapple bite optimized for final movement.

[boastOne43]

29. It seems odd...

that they would cut that down before clearing any of the debris around and below the core column.

[petgoat]

34. Maybe it had stuff hanging on it so it was dangerous. nt

[Christophera]

36. Not a Core Column (they didn't exist)-Interior Box Column, Outside The

core.

The elevator pit is between us and the column. Molten steel was below. On the far side it is clear, A man can be seen working there.



The Twin Towers had tubular, steel reinforced, cast concrete cores. Here is a page documenting them with raw evidence.

http://concretecore.741.com/

[jschurchin]

12. See that slag on the face of...........

that column? Slag ALWAYS forms AWAY from the torch. Whomever cut that column did it from the inside.

[Jazz2006]

13. What do you mean by "from the inside"?

From the inside of what?

Do you mean from indoors or from inside of something else or from the "inside" side of the column or from the "other side" depending on the camera angle or .... something else?

And, why do you say it say it was "from the inside" (whatever that means in the context of that post)?

[jschurchin]

21. Have you ever used a Oxy/Acetelyne torch to cut steel?

[Jazz2006]

23. Not since high school.

[LARED]

25. I have

I have also have used carbon arcs to cut steel. Never used Thermite to cut steel (I don't think anyone has in the context of this type of demo)

Based on the image I would guess the North, East and West sides were cut from the outside. The top section was then lowered while still connected on the south side to allow the final cut to be performed safely. Once it was lowered and properly supported the cut could then safely be made from the inside, allowing the piece to fall down away from the cutter.

[jschurchin]

27. My thoughts also LARED.

The amount of slag looks about right for a 3-4" thick plate. This is what I meant from "the inside", Jazz.

[Jazz2006]

28. Thanks.

[Christophera]

35. You Are right, Note Hole Along Top Edge - Cut From Inside.

Along the top edge there is a dip in the horizontal cut. It would be very likely a slightly specialized slavage torch handle was used. Simply cut a hole big enough to see through with the torch handle sticking through it and out of the hole. A falsework is put in a few feet back from the top cut that has a smooth horizontal rest or horizontal fence for the outside handle to slide on. The torch pivots in the bottom of the hole while the extended exterior handle slides on the fence. The torch is lit, adjusted, inserted into the hole and carefully brought to the back inside of the opposite side of the column right in one corner. After preheating, which really doesn't need to be watched after its started, a slight puddle is observed and the oxygen valve depressed on the handle with one had while the other hand guides the extended handle along the external horizontal fence in one direction making the torch tip travel the other, pivoting at the hole, blowing slag out its cut on the far face of the column.

[LARED]

15. Thermite?

Have you considered carbon arc cutting methods. I am pretty familiar with the various carbon arc cutting methods availiable and based on the amount and position of slag seen, the direction of the cut, and the difficult location of the work, it is almost without doubt a carbon arc method.

[Christophera]

30. Not A Thermite Cut. It is an OXY/Acetlene Salvage Cut. No Thermite Cut

images are around. I did see one in 2002 but have not seen it since. There was mass thermite but it was all in the basement or first floor.

Below is an example of a column cut with explosive shear on the left and a salvage cut from a torch on the right.



Yes there was lots of rebar at ground zero here is More rebar + max sand and gravel

I cannot say much for your experts because that salvaged column with all the slag hanging off of it is absolutely a torch cut.



Steel cut with thermite is every bit as destinguishable as the 2 cuts shown at top. Thermite cuts are smooth rounded edges, approximating straight lines along where the thermite was in contact with the steel. There is often sulferous residue or sprinkling of crusty residue, corners tend to be rounded.

Not trying to diss your post, good perspective and effort, just want you to have the best information to use.

Chris

[boastOne43]

40. The cut doesnt make sense.

why would a worker make a cut TWICE as long as he had to? it just doesnt make sense. this is exactly how controlled demolition workers cut main columns to enable collapse.

[LARED]

42. The cuts are made at an angel to facilitate

removal of molten metal

[Christophera]

63. Cut At Angle Longer, Harder To Move Metal: Hinging Action Intended

The diagonal cut in the column creates a deeper, longer cut in the tube walls. That deeper cut makes it hard for the oxygen jet to blow metal out of the cut. The molten steel tends to cool and solidify before it is out of the cut if the tip is not advanced with precision, slowly. Any shaking at all causes the jet to leave a molten puddle where the oxygen no longer hits and the burning action of the steel ceases. When this happens the puddle cools and stops moving out of the cut.

The best thing to assure the metal moves out of the cut is an absolutely steady torch tip that advances slowly with the jet blowing the molten steel freely out. Shorter, shallower cuts are much preferred even if they are horizontal.

Cutting a column diagonally makes it so a small connection left for the purpose allows the column to hinge with a horizontal travel away from areas where control might be lost by the machine doing the move.

[Christophera]

39. Rebar And 17 Foot Thick Base Of Concrete Core, Interior Box Columns

This is the one piece of the concrete core left above ground. The tightly coiled steel on top of the core wall can only be high tensile rebar.

[boastOne43]

41. another photo...more evidence?

more evidence?





This photo shows at least two, and probably more, apparently thermite-severed large core columns falling like trees during the collapse of one of the towers of the World Trade Center. The ladder-like steel connection between the columns can be easily seen. These columns are clearly not perimeter columns but are two of the crucial load-bearing core columns.

The evidence in this photo indicates that these towers were cut with thermite. This can be seen from the ends of the columns, which are still burning white hot and issuing a large amount of white aluminum oxide - a tell-tale sign of a thermite reaction.

[Christophera]

43. Photo Easy To Misinterpret - Interior Box Columns, Not Core Columns

The below photo shows the inner wall of the outer tube of the "tube in a tube" construction. The core appears empty because the concrete blew up. There is a link to a site that explains this in detail at the bottom.



The heavy steel columns are interior box columns and inside the core we see below, elevator guide rails, much smaller steel. The horizontal beams connecting the interior box columns match the proportions with the top photos. Each beam above represents one floor.



Most importantly: There are many other photos that should show the core columns that were supposed to exist in the core but do not. Yet another lie by FEMA in the WTC report. The towers had steel reinforced cast concrete tubular cores.

If there were central, steel core columns they would show here.



In a way similar to how the spire is formed by one interior box column at the out side corner of the concrete shear walls of the core.



Below the fine vertical elements are rebar. This photo is taken just a second after the previous and the above photo establishes scale for this photo. The spire above is an interior box column 14 inches wide and perhaps 2 feet deep.

Below is 3 inch rebar on 4 foot centers.



Here is a site documenting the concrete core with raw evidence and links to engineering sites.

http://concretecore.741.com/

Ther was thermite used but there is little evidence of it used above the first floor.

Here is a site documenting how free fall was attained by concrete shattered from within by explosives cast into the concrete core and floors.

http://algoxy.com/psych/9-11scenario.html

[sabbat hunter]

49. please stop

posting your personal concretecore.741.com site. it is loaded with popup and could be damaging systems.

if you must post your vantiy site, please clean up the popups.

thanks

[Christophera]

51. Stop Because Of Fear? Fear Of OP. System Damaged By Website?

Do you really think I am the person to talk to about this? I have nothing to do with the pop ups. Contact the provider of the server space. I simply supply a link.

[sabbat hunter]

53. just dont supply that link

it could be infecting computers with viruses. and it isnt up tp the provider of the server space. it is up to whom ever designs and maintains the website to fix those problems. if that is your website then please fix it. if it isnt yours then stop posting it please.

thanks

[Christophera]

54. Free Server Space Users Have No Control Over Pop Ups

and that is what that site is on.

[sabbat hunter]

55. then i suggest

you find a better place to host your website. whether one agrees with you or not is irrelevant here, a site with a ton of popups makes the site look bad and people not want to visit it.

peace
david

[mirandapriestly]

56. I don't get any pop ups

I'm sure most people can figure out how to install antispyware or get some other kind of protection for their system. Thank you for your concern, however.

[sabbat hunter]

60. i am able to do so

but tehre are many peopel that cannot. also with some popups, even though they are blocked they still get into your system and if they contain spyware can damage your system. antispyware programs are not perfect either.

a much better solution is not to have the popups in the first place.

[mirandapriestly]

45. Good find, I see the white smoke at the base of the still standing

columns. What other explanation could there be for those columns falling? How would they be cut with thermite, do you think? (what method?). I really can not think of an "innocent" reason that those would fall.

[Christophera]

47. Explosive Shear - Cutting Charges Jones Describes. Thermite In Basement

Below is what the floors looked like at the joint with the interior box columns making a collapsing plane of high pressure gas. Extreme shaping. I actually recall a comment in the narration of that 1990 documentary about the very tight tolerences in the plates that encircled the columns cast into the concrete floors. I'm going to go further with that. I even remember a comment about the PA in that they were upset about the videographers learning and including that information about the tolerences. There was another instance where the videographers learned something provocative and mentioned it. The special plastic coating on the rebar was flammable; the excuse for using only welders with security clearances to butt weld the 3 inch high tensile steel rebar in the cast concrete shear walls. The producers had to pry this out and justified it because that weld slowed the entire project, the bottleneck in construction.

Oh, one more. The floor evacuations just before concrete was poured.

Steel column cutting floors.



Explosive shear on the left, torch cut on the right.



In the photo below, we see interior box columns cut and rolling outward with the force of the exploding core. That was the north tower. It was somewhat inconsistent compared to the south

[mirandapriestly]

48. So you think thermite only in basement, lower floors

and C4 in the plates abutting (is that a word?) the columns? The tapes recently released of those poor people trapped on the 106th floor made it clear to me that there was an extreme amount of heat & smoke on these floors, but no fire. This pointed somewhat to thermite to me. What do you think was happening there? I don't think there were any substantial fires after the fireball dissipated.

[Christophera]

52. Small EVID. Of Thermite Higher In Tower. Large EVID. At Base.

Thermite up higher would tend to be visable, and there is some video that shows bright spots inside the towers at upper elevations. What could be molten steel is seen as well. Aluminum is seen splashing from a floor. So it cannot be eliminated altogether as a possibility. If it was there, not much was present.

I assume you are talking about the north tower when mentioning the heat and smoke. WTC 1 had 2 holes in it, one went all the way through the core. That's where the engines went and fuel followed them. The fuel detonated in the confined space of the core, blowing doors off and spreading fires near the core that ended up drafting up the core and through the holes in it. This kept a considerable amount of smoke rising in the tower that drove people onto the roof and the core unusable for escape.

[mirandapriestly]

57. But what would maintain high temperatures

The jet fuel fire was out in minutes, then supposedly this spread to furniture and other flammables, but I just don't see how the type of furniture and other objects in the wtc would be able to sustain such a fire that would produce such heat. It's back to the original question. So I was wondering if thermite was responsible for the heat WITHOUT FIRES that was on those upper floors of the north tower, it was causing those people, God bless them, to jump. It is obvious that there were no fires, just heat, from those calls that were released.
and Jones has the white flame on an upper floor, like you said...

Do you think there was enough to sustain the original fire?

[Christophera]

58. Fuel Soaked Wood And Carpet And Fuel In The Core

We don't really know how much heat was in the towers. We know there wasn't enough to melt steel and it doesn't take much to get people to choose jumping instead of baking.

We also know that thermite was the only thing that could have created the molten steel.

Just coating the interior of the core, elevators and stairways with fuel and letting it burn is enough to heat up and smoke out people. The observation floors and the hat truss might make a poor seal, good pocket for heat. I think I remember reading some scraps of testimonials of observers of the towers that people went up to the top, then down to floors below 106.

For thermite to be effectively used it would have been on the south side of the north tower, a few floors at most. The perimeter walls would provide the most effect matching what we saw. The top of WTC fell to the south, so thermite on the south side would remove bearing ability and cause the top to fall that way.

Which side of the tower is Jones white flame?

[mirandapriestly]

59. Oh, yeah, that makes sense

I guess it is still shocking to me how few fires there were in the towers.

Here is the link for Jones comparison of a thermite reaction to what looks like a thermite reaction on the north side of the south tower (I think). There was another picture before on his site, but I can't find it. This actually might be better although it isn't as obvious in the white stage.
http://www.checktheevidence.com/911/Thermite2.htm

[Christophera]

61. Even Smoldering, Fuel Saturated Gypsum And Wood Piles Emit Lots Of Heat

Kerosine saturates materials quicky. Sand can be saturated lightly and then be ignited, when it gets hot enough to gas off, the fuel is depleted quickly. Sand can get that hot without burning, moving air without burning. Flammables of any kind wick the fuel in and the fires wick it out as it consumes, they do not get that hot so the gassing off point goes longer until ambient temperatures are high. The saturated stuff in the core and on the floors below the impact was burning like that.

Not enough to melt anything, but enough to continue to burn and ignite new fuel, and draft up the core to heat upper floors. The seals around the hat truss may have been as light as one sheet of drywall where the steel structures pierced the walls. The fuel explosion at impact may have broken lots of that out allowing a draft of heat and smoke onto the observation deck.