Glass a "Rare Find" at Ground Zero

Joined: September 27th, 2008, 6:07 pm

January 10th, 2010, 12:13 am #1

image wrote:GLASS SHARDS: Glass was a rare find at Ground Zero, where these shards were recovered. The collapse and fires pulverized and melted most of the glass from the Twin Towers' 43,600 windows.
- NYPD Police Museum exhibit "9/11 Remembered" - photo source lost, but similar photos found here and here

wrote:You didn't find a shard of glass-- anything that looked like it would be used by a person, you just didn't see it. It was just concrete, steel, that was it-- and dust.
- FDNY Engine 285 firefighter in "Collateral Damages" (2006, Turn of the Century Pictures, Inc.)
wrote:It was like the surface of another planet. All there was, was powdered debris and metal. It was a – a very strange scene.
- Chief Daniel Nigro (FDNY Chief of Department 2001-2) in "Conspiracy Files – 9/11: The Third Tower," BBC TV 2008 — watch
wrote:You have two 110-story office buildings. You don't find a desk. You don't find a chair. You don't find a telephone, a computer. The biggest piece of a telephone I found was half of the keypad, and it was about this big. The building collapsed to dust. How are we supposed to find anybody in this that there's nothing left of the building?
- FDNY Engine 7's Joe Casaliggi in the Naudet documentary "9/11" at vrt 1:25:20 in TV version at ... aries.html
ABC News report Sept. 13: 600,000 square feet of glass in the towers. Dr. Stephen Levin mentions "fine glass powder" at vrt 1:53.

43,600 windows were a rare find in the debris pile. Let's ask why.

wrote: Powerful gusts can shatter windows, so for the sake of safety tempered glass eight times stronger than needed was specified. Planners designed the towers to withstand prolonged winds of 150 miles per hour.
- Angus Gillespie, Twin Towers: The Life of New York City's World Trade Center, Rutgers University Press, New Brunswick, NJ, 1999, p. 81.
wrote:The twenty-two-inch spaces between the columns are for the windows, which are recessed ten inches in order to shade them from all but direct sunlight. The architect specified a bronze-tinted, heat-reflective glass for the 43,600 windows.
- Gillespie, p. 108 (The glass itself was eighteen and a half inches wide. The 107th floor of the North Tower had 30-inch wide windows, for the Windows on the World restaurant. Likewise, "extra-wide windows" were needed for the observation deck of the South Tower.[p. 216])

"The columns are twelve inches deep from the outer skin of the aluminum to the glass...." [ p. 167] (bonus detail)

The windows spanned from floor to ceiling. Gillespie estimates the surface area of the towers to be about 30% glass (p. 165), as opposed to the predominant style of modern architecture known as the "International Style," which uses on average about 60% glass.
wrote:Each tower has fifty-eight vertical columns of windows per side, and each column is numbered. The [window washing] machine does about twelve columns of windows per day, so it takes five working days, or one week, to do one side of the building. There is a turntable at each of the four corners on the roof, so at the end of the week, the machine turns the corner to deal with another side. It takes four weeks, or one month, to do the whole building.
-p. 215


OK, there was a lot of glass! Where did it go, if not into the clouds of dust?
wrote:The dusts released from the WTC building collapse are largely composed of particles of glass fibers, gypsum, concrete, paper, and other miscellaneous materials commonly used in building construction. ... iveSummary

More specifically, glass fiber made up 40 percent of all the samples collected and studied by Paul J. Lioy, et. al. ( ... -full.html):

It is important to know that the windows weren't the only form of glass in the place. Not only were there light fixtures, TVs and monitors, but also there was fiberglass insulation. "These three [dust] samples were composed primarily of construction materials, soot, paint (leaded and unleaded), and glass fibers (mineral wool and fiberglass) ." (Lioy, et. al.)
wrote:The Cortlandt Street sample was mainly composed of construction debris [including vermiculite, plaster, synthetic foam, glass fragments, paint particles, glass fibers, lead (Figure 3), calcite grains, and paper fragments], quartz grains, low-temperature combustion material (including charred woody fragments), and glass shards. Chrysotile asbestos fibers were estimated to comprise < 1% of the sample by volume....
- Lioy, et. al.

Figure 4. "Glass fiber detected in the Market Street sample."
Lioy wrote:Approximately 35% of the volume of the sample was in the form of loosely consolidated clumps of fibrous lint, of which the greatest portion was glass fibers. An example of the typical form of the glass fibers is shown in Figure 4. In many cases the width was approximately or equal to 1 µm (to > 10 µm), and the length ranged from 5 to 100 µm. The fiber shown in Figure 4 is not a "clean" glass fiber; other materials are agglomerated along the rod. This is typical of features noted for many different types of particles in each sample. The SEM analysis of the fraction < 75 µm in diameter revealed many glass fibers and cement particles, some in a fibrous form containing calcium, silicon, and sulfur, and some particles were composed of calcium carbonate....
The ... html Spectroscopy Lab provides an important detail:
wrote:Use of slag wool, a type of mineral wool insulation, was widespread in the WTC towers (Hyman Brown, personal communication) as part of fireproof coatings on steel girders and the undersides of floors, thermal insulation around glass windows, and possibly in ceiling tiles. The apparent widespread use of slag wool and its brittle nature may explain its presence in all of the dust samples as a volumetrically significant component.
However, this may be misleading because the first sentence in the paragraph read: "SEM energy dispersive analysis indicates fibrous glass with elemental composition closely matched by slag wool in all dust samples analyzed by this method." This still does not rule out the presence of glass SHARDS.
wrote:Small shards of glass containing mostly silica and magnesium were also found.
This cloud comprised a complex mix of pollutants, among them the products of combustion of 91,000 L jet fuel, pulverized building materials, cement dust, asbestos, microscopic shards of glass, silica, heavy metals, and numerous organic compounds....
- Maoxin Wu, et. al., "Case Report: Lung Disease in World Trade Center Responders 
Exposed to Dust and Smoke: Carbon Nanotubes Found in the Lungs 
of World Trade Center Patients and Dust Samples" (emphasis added)

Another dust study gives us this:

source: ... index.html

It's important to consider that Silicon is the 8th most abundant element in the universe (according to ), so it's a large part of concrete also. BUT, more important, Silicon makes up about 70% of most glass. SiO2 is mixed with other materials to lower the melting point to about 1500 °C (2700 °F) -- see -- so if the NYPD Museum is correct and the glass did melt, there were some really freaking hot temperatures going on! AND THERE WERE. (See "Molten Steel & Extreme Temperatures at WTC")

Could a building collapse have pulverized the bulk of the extra-strong glass into such a huge quantity of microscopic shards? I think not.


One professional source claims there were large quantities of glass recovered. Their number is hilarious. Either they were counting the omnipresent, vitreous dust... or they were including the 600,000 square feet of glass once a part of the towers, assumed to be there in the debris pile.
wrote:The initial debris estimate included 125,000 tons of glass, 250,000 tons of steel, 450,000 cubic yards of concrete, 12,000 miles of electrical cable, and 198 miles of ductwork.
- Phillips & Jordan, Inc., "Anatomy: World Trade Center/Staten Island Landfill Recovery
Operation," Phillips & Jordan, Inc., p. 2. Document originally at the Disaster Recovery Group web site (dead link) but cached at

There also we can read: "Phillips and Jordan, Inc. (P&J) was called to New York by the U.S. Army Corps of Engineers. P&J was tasked by the Corps as their Advanced Contracting Initiative (ACI) Disaster Debris Management Contractor to serve in a strategic planning and monitoring role." These people were not on the pile in the bucket lines, digging in those first hours. They only know there SHOULD HAVE BEEN tons of glass.

* UPDATE 2 *

Please scan through the published work of Steven E. Jones, Jeffrey Farrer, Gregory S. Jenkins, Frank Legge, James Gourley, Kevin Ryan, Daniel Farnsworth, and Crockett Grabbe, "Extremely high temperatures during the World Trade Center destruction." In addition to elemental composition analysis using a scanning electron microscope, you will find this micrograph, or optical microscope image of WTC dust plainly showing dried molten metal and silicate, or glass:

** UPDATE 3 **

Engineer Mark Basile discusses his personal examination of the WTC dust in this video presentation, and at this specific spot describes once-molten silicate spheres -- with magnetic properties.

Joined: September 27th, 2008, 6:07 pm

April 24th, 2011, 8:05 pm #2

Did some reading. Found some relevant quotes:
wrote:The dust also contained a large amount of an unusual material: glass fibers. Both towers were 110 stories high and had 880 stories of windows in total since there were 110 stories with four walls times two sides of windows. These windows had been crushed by the collapse of the towers. These were different than other materials since the glass windows disintegrated into fibrous dust as well as glass chards [sic].
- Paul J. Lioy, Dust: The Inside Story of Its Role in the September 11th Aftermath, Rowman & Littlefield, New York, 2010, p. 96.
wrote:[O]ver 50 percent of the mass of the WTC dust was made up of the cement and carboneous materials. (Carbon is the fourth most abundant element found in inorganic and organic forms.) As part of the carboneous materials, there were significant quantities of cellulose (paper). Most of the rest of the mass was made up of the glass fiber materials. Some of the glass fibers were formed from the disintegration of glass windows. Other fibers released during the collapse would have been part of interior wall board and ceiling tiles. Some of the fibers were characterized as slag wool and would become known as a specific and identifiable component of the WTC dust.
- Paul J. Lioy, Ibid., pp. 96-97.
wrote:The fibrous material was composed of disintegrated material that was present in building interiors or on the exterior. As time went on, we would call a large portion of it slag wool, based on work by the United States Geological Survey. However, there were other types of fibers that became of interest, including glass. The composition of the nonfibrous portion of the dust is simple to understand….
- Paul J. Lioy, Ibid., p. 101.
…as opposed to the abundant, microscopic, fibrous glass which is hard to understand, right?
wrote:The WTC dust contained construction debris, and the materials detected included vermiculite (a natural insulation material), plaster, synthetic foam, glass fragments, paint particles, glass fibers, lead, calcite grains, paper fragments, quartz grains, low-temperature combustion material (including charred woody fragments), and glass shards.
- Paul J. Lioy, Ibid., p. 105.
wrote:The glass fibers were also very curious. Since the buildings were constructed with 110 stories of glass windows, many windows were crushed during the collapse. They, too, had returned to dust, resulting in many small glass fibers. These fibers could be highly irritating upon inhalation into the lung and deposition within the upper airways.
- Paul J. Lioy, Ibid., p. 111.

Chapter 8 of the Lioy book quoted above is here. Many interesting factoids in there, including notes of "charred woody fragments" in all of the WTC dust samples. Not once does Lioy consider any "conspiracy theories," of course. At least not in chapter 8, which I read first. "The penta-mixture (BDE-47, BDE-99, and BDE-100) detected in the WTC dust was used in flame retardants for polyurethane foam, which is common as padding in office furniture. The highest BDE concentration was for BDE-209, which is used as part of thermoplastics in computers." - p. 118. ... The point being that much of the furnished 12 million square feet of office space was pulverized (or exploded) into dust. And not much of that - next to nothing from what numerous sources say in the video compilation below - was recognizable.