GlassCon Takes on Thin Glass and Acoustics

GlassCon Global 2016 began its educational presentations Thursday afternoon in Boston with a variety of glass-related topics covered simultaneously in three separate tracks.

Jurgen Neugebauer, one of the many speakers, kicked off one of the tracks discussing thin glass.

“What is thin glass? It’s thin, and it’s glass,” he quipped at the beginning of his presentation. Neugebauer, of the University of Applied Sciences in Joanneum, Austria, said thin glass is typically defined between 0.1 and 2 millimeters thick. He noted, however, that the thinnest glass that has been created is .055 millimeters thick.

Thin glass can be produced in two material compositions—as soda lime silicate glass and aluminum silicate glass.

While float glass is the most widely known method of making flat glass, thin glass can be produced in two other ways. These are the “down draw” and “overflow fusing” processes.

In the down draw process, “the molten glass flows through a small gap at the bottom of the melting tank down and is down cooled by annealing furnaces … this controlled down cooling process the glass is cut into certain sizes,” according to Neugebauer. In the overflow fusing process, “the molten glass is poured into an overflow gutter,” he said “From this gutter, molten glass flows on both sides down and fuses at the bottom point of the gutter… After the down cooling process, the glass is cut into panels with certain sizes.”

Thin glass can be pre-stressed by thermal strengthening, “but this has its limits,” he said. “The thinner the glass is, the more likely roller waves will arise.” Because of this, Lisec developed a method to transport the glass on an air.

Another way to pre-stress glass is by chemical treatment via “ionic exchange.”

Neugebauer then discussed how the strength of the glass can be tested and the different factors that affect it.

He said size and stress/load on the glass over time “could cause a significant reduction of bending tensile strength, which represent the design value for structural design of glass applications.” Because of these factors, thin glass usage will require further evaluation and testing.

In another presentation, Werner Jager of Ai3 talked about noise absorption and sound scattering of building envelopes.

“The urbanization is one of the main challenges for urban planners, as of 2050 it is forecasted that 65 percent, or approximately 6.5 billion people, of the world population will life in urban areas,” according to Jager. “Traffic, as a major source of noise, will increase further leading to even more sound and noise in inner city centers.”

Jager said because of this, acoustics in urban areas continue to be a growing concern and has prompted the building industry to look at how façade designs can address it.

“Acoustics behave like light,” he said. “For example, when you have a concave design of a façade, it can concentrate sound just like light.” He said a convex design can instead distribute the noise.

“This is just one way to re-engineer the curtainwall from an acoustics point of view,” he said, discussing diffuse reflection and other designs that could help alleviate noise, such as a series of small semi-circle shapes.

Stay tuned to USGNN.com™ for continued coverage of GlassCon Global 2016.

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