The 9/11 Forum

David B. Benson wrote:Trippy --- On that floor plan, notice the AC ? ? Exhaust ? towards the lower left outside the core. It is a void of some sort throught the beamed floor (type 12).

Yes, I noticed that.
I also noticed that the HVAC shafts are all on one side of the building.
Based on the reading i've done while I was at home on my lunch break, it appears the HVAC system was divided into three zones on each floor (not actually the information that I was looking for).

I wish I could track it down, but there's a U of O Proff that uses the WTC HVAC layout (or used it anyway) as a case study for (one of) his post grad architecture paper(s).

Trippy wrote:I also noticed that the HVAC shafts are all on one side of the building.

I think those are the main supplies and returns for further up. There are also quite a few other HVAC shafts sprinkled around. I suppose those are for more local use.

David B. Benson wrote:

Trippy wrote:I also noticed that the HVAC shafts are all on one side of the building.

I think those are the main supplies and returns for further up. There are also quite a few other HVAC shafts sprinkled around. I suppose those are for more local use.

The impression I got was that floor 75 and or 76 contained HVAC MER's that serviced 16 floors above and below them (and there was an equivalent HVAC MER in the roof).

I don't know how those blue prints correlate to the 77/79 dust jet, but i'd be almost willing to place money on the dust jets as being on the same side of the building as the HVAC shafts, and i've also seen it stated that the air space created by the floor joists were used as the return air plenum, but i'm not sure where the exhaust shaft was (or indeed, even if there was one).

But am I the only person seeing a pattern emerging here?

One of the (stronger?) dust jets emerges one or two floors above the floor with the HVAC MER on it.
The HVAC ducts all appear to be on one side of the building, and the dust jets appear to have emerged on one side of the building...

Trippy --- I suppose that the top of the floor plan is the north side of WTC 1. If it is marked, the 500 column line was on the north side of WTC 1.

Edited to add: The HVAC ventilators were around all four faces of both of the pair of mechanical floors, 75/76 for the middle pair.

Must be time to actually gather the accurate timing and positional data for each jet don't you think ?

(Discussing conclusions and sources without the actual source data would seem to be very prone to dry labbing...)

Will gather visual data for the most discussed *dust jet* and post asap.

Dust Jet #1



Accurate floor position should be possible.

Will add another angle to determine West face position asap.

David B. Benson wrote:Trippy --- I suppose that the top of the floor plan is the north side of WTC 1. If it is marked, the 500 column line was on the north side of WTC 1.

DURRRRRRRRRR! *Face palm*

There's a frigging compass rose in the top left corner of the plan - how did I miss that!!?

Which would place the exhaust shaft in question (Yes, it's labled AC & ???? Exhaust Shaft) on the West side of the building, South of the midline.

femr2 wrote:Must be time to actually gather the accurate timing and positional data for each jet don't you think ?

(Discussing conclusions and sources without the actual source data would seem to be very prone to dry labbing...)

Will gather visual data for the most discussed *dust jet* and post asap.

Thanks.

Have video of the West face, but getting a *clear* frame is proving difficult.

It's pretty clear however, that Dust Jet #1 originates North of the Centre of the face.

(Which would seem to negate correlation to the HVAC duct mentioned.)

Will post a clear image when I can.

femr2 wrote:(Which would seem to negate correlation to the HVAC duct mentioned.)

That duct almost surely was only through beamed floors, not office trussed floors.

femr2 wrote:Have video of the West face, but getting a *clear* frame is proving difficult.

It's pretty clear however, that Dust Jet #1 originates North of the Centre of the face.

(Which would seem to negate correlation to the HVAC duct mentioned.)

Will post a clear image when I can.

There is, however, another HVAC duct north of the center line of the west face, with only 'floor space' between it and the perimeter. This one appears to have a corresponding shaft on the east face though.

I count it as being (about) 26 (perimeter) columns back from the North West corner.

Addenendum:

Between Colums 436 and 439 if i've read the blue print correctly.

Trippy wrote:There is, however, another HVAC duct north of the center line of the west face, with only 'floor space' between it and the perimeter. This one appears to have a corresponding shaft on the east face though.

"AC Shaft" ends at floor 82 (above which OOS space expands into core region with significant reduction in elevator shafts, and cessation of the stairway also.)

femr2 wrote:

Trippy wrote:"AC Shaft" ends at floor 82 (above which OOS space expands into core region with significant reduction in elevator shafts, and cessation of the stairway also.)

Doubt the reduction in elevators but certainly all three stairways were still there (code). The upper escalator ended at floor 80?

There is a typical trussed office floor plan in NCSTAR1--2A.

David B. Benson wrote:Doubt the reduction in elevators but certainly all three stairways were still there (code). The upper escalator ended at floor 80?

There is a typical trussed office floor plan in NCSTAR1--2A.

I have a full set of the LERA plans (same set as the one posted by Trippy earlier was from)

Er, hang on...

http://911research.wtc7.net/wtc/evidence/plans/doc/pac1TowerA/A-A-140_0.png
Floor 83. The stairway next to the discussed duct labelled "AC Shaft" has gone. The shaft has gone. And the OOS space has expanded into the core region. Significant reduction in elevator shafts too.

femr2 wrote:

Trippy wrote:There is, however, another HVAC duct north of the center line of the west face, with only 'floor space' between it and the perimeter. This one appears to have a corresponding shaft on the east face though.

"AC Shaft" ends at floor 82 (above which OOS space expands into core region with significant reduction in elevator shafts, and cessation of the stairway also.)

The stair way continues, they just moved it on the floor plan every few floors, and connected it with (protected) corridors to avoid people walking down a 110 storey vertical shaft.

As far as the AC duct goes, on floor 82 there's a pipe shaft between the AC plenum and the AC shaft, and the pipe shaft appears to extend all the way up to floor 108.

On floor 83, the area imediately above this area is open space.