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Dann will ich mal versuchen darauf zu antworten:
Ich weiss nicht von welchen Konstruktionsschwächen geredet wird.
Gerade im Zusammenhang mit dem Bild der Beschädigung.

Eine offensichtliche Konstruktionsschwäche hatte das WTC7: Der Brandschutz.
Aber da besteht nur ein Zusammenhang mit den Beschädigungen aus den Trümmern von den Türmen, dass die eine Schneise durch die Ebenen geschlagen hat, worüber das Feuer auf andere Stockwerke ausbreiten konnte.
Aber die Brände hatten sich ja auch so weiter ausgebreitet, auch in Bereich, die nicht beschädigt waren.

Sind meine Interpretationen des NIST-Berichtes richtig?

Laut NIST waer die Groesse und Verteilung der Feuer genauso einzuschaetzen wie in Feuer in anderen Gebauden - ohne Beschaedigung.

"Their growth and spread were consistent with ordinary building contents fires." NCSTAR 1A, p xxxii

Es gibt keine Beweise, dass sich die Feuer ueber mehrere Etagen hinweg ausgebreitet haetten. Sprich alle Feuer waren beschraenkt auf eine Etagenhoehe:

"There was no evidence of floor-to-floor fire spread until perhaps just before the WTC 7 collapse. Thus, the fire-rated floors were successful as fire penetration barriers." NCSTAR 1A, p 55

Auch der Feuerschutz des Stahls war im Einklang mit den gesetzlichen Vorschriften.

"The instructions to the bidders for the WTC 7 job were to bid on a 3 h rating for the columns and a 2 h rating for the fluted steel decking and floor support steel, which corresponded to the more stringent fire resistance requirements for Type 1B (unsprinklered) construction." NCSTAR 1A, p 7

"Private inspectors found that the applied SFRM thicknesses were consistent with these values." NCSTAR 1A, p 7 (also see NCSTAR 1-9, table 8-1, p 340)

Infokrieger119 schrieb:Sicher, dass das Video von einem Debunker stammt?
Macht mir nicht gerade den Eindruck.

Das macht auf mich eh ein ziemliche chaotischen Eindruck bei der Argumentation.
Da wird ja alles wie Kraut und Rüben durcheinander gemischt.
Stahlbauten mit Stahlbeton, Sprengung mit Hydraulischen Abbruch (wage ich zu bezweifeln das das Beispiel einer war), WTC7 mit den Türmen...
Und damit will er beweisen, dass WTC7 mit Hilfe einer typischen Implosion (Decken ziehen Aussenfassade nach innen) zum Einsturz gebracht wurde.
Aber das Dach stürzt auch bei ihm zuerst ein.

Genau solche Videos sind es, die mir das Leben schwer machen eine Sprengung zu beweisen.
Die sind es, vor denen ich mich dauernd distanzieren muss, so dass man mich meist für einen Debunker hält.

Gruss Moses

NIST NCSTAR 1-9 Vol1, Seiten 73,74:

4.4.2 Details of the Standpipe and Sprinkler Riser Systems
The primary water supply for WTC 7 was provided by the 12 in. water main beneath Washington Street.
Fire department connections (FDCs) were located on the south, east, and west sides of the building. A
3 m3/min (750 gal/min) manual fire pump that served the entire building was located on the ground floor.
Three vertical zones within WTC 7 were identified based on the water source and flow path (Figure 4–
3).2

Low zone. A 2 m3/min (500 gal/min) automatic fire pump, located on the ground floor, supplied
the sprinkler and dual standpipe systems from the ground floor through the 20th floor. A cross
connection main, located on the 20th floor, connected the risers to each other; an isolation valve
could be closed to isolate the risers from each other. The pump was provided with an emergency
power source via an automatic transfer switch (Syska & Hennessy 1984).

Mid-level zone. The 21st floor through 39th floor sprinkler systems and dual standpipe systems
running from the 21st floor through the 44th floor were supplied from two connected, two story
high, gravity-fed water storage tanks on the 46th floor. Each tank had a holding capacity of 70 m3
(17,500 gal). The water could be used for both domestic plumbing and fire suppression, although
the last 7,500 gal in each tank was reserved for fire use. The make-up water to fill each tank was
supplied by three 1.7 m3/min (435 gal/min) capacity booster pumps via an 8 in. domestic express
supply riser from the second floor. Each pump was provided with two float switches in each
tank. A single pump operated when the water level dropped to a set point established by the
electrode control unit. The pumps operated individually, but would operate simultaneously if the
demand exceeded the capacity of one pump (Syska & Hennessy 1984), whether due to domestic


High zone. The 40th floor through 47th floor sprinkler systems and dual 45th floor through 47th
floor standpipe systems were supplied from the storage tanks on the 46th floor via a 2 m3/min
(500 gal/min) booster pump on the 46th floor. The pump was a single stage pump rated for
380 kPa (55 psi) at 2 m3/min (500 gal/min) (Syska & Hennessy 1984). The water discharged
from the tank on the 46th floor, flowing down to a cross connection on the 44th floor where it fed
each riser.

NIST NCSTAR 1-9 Vol1, Seite 78:
The only evidence of fire on
the 19th floor is a single photograph showing smoke marks above two windows on the far south of the
west face (Chapter 5). NIST was unable to obtain evidence to indicate why this fire did not spread.

The Ignition and Spreading of the Fires in WTC 7

In Chapter 9 of NIST NCSTAR 1-9 we encounter one of the most significant problems with attempts to unravel the mystery of why and how WTC 7 collapsed late in the afternoon of September 11th, 2001 – the question of where and how fires started in building 7. On page 376 of NCSTAR 1-9 we read:

“… the ignition and early course of the fires (in WTC 7) were unknown because they were presumed to have occurred in the damaged and heavily smoke-shrouded southern portion of the building.”

NIST’s knowledge of the fires in WTC 7 is therefore based on images of the exterior faces of the buildings. Unfortunately however, as acknowledged by NIST, most of the burning of combustible materials at the WTC on 9/11 took place beyond the views available through exterior windows well inside the buildings.

NIST propose, and it appears to be a reasonable assumption, that the fires in WTC 7 started near the south face as a result of the collapse of WTC 1 at about 10:29 on the morning of 9/11. However, even this assumption is problematical because fires on the crucial 12th and 13th floors of WTC 7 were not in fact observed until after 2:00 p.m., and then only on the east face of the building.

Faced with the problem of modeling the spreading of the fires in WTC 7, NIST begins its computer simulation with a set of 2 MW fires, presumably one per floor, for floors 7, 8, 9, 11, 12 and 13. These hypothetical fires are stated to be “roughly equivalent to small, single workstation fires”, but NIST is quite vague about where these fires were located other than “near the southern face of the building”. What is more, for the fire to spread to NIST’s satisfaction on floor 8, two fires were hypothesized to start at this level within the building.

Other aspects of NIST’s simulation also appear to be quite arbitrary and unphysical. Thus the fire on floor 12 was prescribed to start “near the center of the south face at an assigned time of 12:00 noon.” This is a strange choice of ignition time given that the WTC 7 fires were supposedly started by flaming debris from the collapse of WTC 1 at 10:29 a.m. It implies that some of the flaming material in the WTC 1 debris that settled near WTC 7 remained dormant for about an hour and a half before spontaneously igniting fires that were subsequently observed on floor 12.

1.0 Fire Intensities and Durations

The way the fires spread in WTC 7 during 9/11 was largely determined by the distribution of combustible materials throughout the building. In NIST’s fire simulations this distribution was approximated by an average fuel load for each fire-affected floor of 20 - 32 kg/m2 or 4.0 and 6.4 lb/ft2, (See NIST NCSTAR 1-9 pages 59 – 60). As shown in Figures 10-15 and 10-16 of NCSTAR 1-9, this fuel loading is calculated by NIST to have been sufficient to sustain temperatures above 400 °C for the floor beams and concrete slab on the east side of floors 12 and 13 for about 2 hours. According to NIST’s fire simulations, floors 12 and 13 were the most severely heated floors in WTC 7; however, there are reasons to question the level of heating claimed by NIST.

NIST’s fire simulation would have us believe that a very substantial heat release rate was sustained for over 2 hours over a floor area of about 500 m2 in building 7. Thus Figure 9-13 of NCSTAR 1-9 shows that a heat release rate of 200 MW was attained on floor 12 at about 3:00 p.m. on September 11th and remained above 200 MW until well after 5:00 p.m. But we need to ask: Is a 200 MW fire consistent with a fuel loading of 32 kg/m2 - the value used by NIST for its floor 12 fire simulations? The answer appears to be no. Thus a 200 MW heat release rate for 2 hours implies a total energy release of 1,440 GJ. If the combustible material on the 12th floor of WTC 7 is assumed to release 20 MJ/kg, we have to conclude that 72,000 kg of office material was combusted over an area of 500 m2, or there was a fuel loading in WTC 7 of 144 kg/m2 – a value over four times NIST’s assumed fuel loading.

That there is a problem with NIST’s predicted fire intensities in WTC 7 compared to the assumed fuel loading is supported by comparisons to other studies of fires in steel framed buildings. For example, the well-known Cardington tests conducted in the U.K. in 1999 measured a maximum heat flux of about 200 kW/m2 over a period of about 1 hour from the combustion of 6000 kg of cellulose-based fuel inside a 144 m2 steel framed structure, giving a fuel loading of 42 kg/m2. Thus we see that in the Cardington tests the total energy release is predicted to be 144 x 200 kW for one hour which equals 28.8 MW for 3600 seconds or 104 GJ. The heat of combustion of the fuel was 17 MJ/kg, so for 6000 kg we would expect a heat release of 102 GJ in good agreement with the predicted energy release.

The main problem with the NIST fire simulation appears to be the calculated duration of the fire on the 12th and 13th floors of WTC 7. For example, if we assume a more reasonable fire duration of 30 minutes, rather than NIST’s excessive 2 hours, we may revise the energy release down from 1,440 GJ to a mere 360 GJ in which case the combustion of 20 MJ/kg fuel would have consumed 18,000 kg of material and the fuel loading would have been 36 kg/m2 in much better agreement with NIST’s assumed fuel load. That these are more realistic figures is also supported by some of NIST’s own studies of the relationship between combustible loads in buildings and classifications of fire severity. Thus M G. Goode in NIST Report No. GCR-04-872, published in July 2004, provided a table showing that fire durations of 0.5 and 0.75 hours are to be expected for fuel loads of 20 kg/m2 and 30 kg/m2, respectively.

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