Volume 50, Issue 6 - June 2015

NewsAnalysis:ACOUSTICAL GLASS

Acoustical Glazing Comes of Age; “Sound Arguments” for Choosing It

The use of exterior architectural glass continues to increase as the industry fights with other building products in the “battle for the wall.”

In that window-to-wall ratio battle, the glass and glazing sector is challenged continually to make sure that with the increase in sunlight, solar heat gain and thermal performance are optimal.

And since energy performance is emphasized in building codes, other factors tend to be overlooked—or at least treated as secondary. One of those factors is acoustical performance. Experts in the field think that sound is gaining attention, and will continue to, as users realize the solutions on the market to attenuate sound while preserving visibility.

“The next battle for the wall could be about acoustical comfort,” says Julia Schimmelpenningh, global architectural applications manager at Eastman Chemical Company, which offers acoustical interlayer solutions. “People are beginning to realize the effect noise has on us physically and psychologically. You see studies about hospitals and recovery rates, or schools, where there are dramatic changes in learning capabilities based on the noise environment.”

She says those factors, coupled with how greater population density in growing cities has affected noise in office, hotel and residential settings, has created a realization that “there is an acoustical problem out there, and it can have an impact on the quality of human life.”

That growing recognition has prompted metropolitan jurisdictions such as New York City to implement E-zone codes in which buildings in certain dense areas are required to meet sound attenuation standards. To help accommodate this, acoustical interlayers, such as PVB, can drastically reduce the transmittance of sound from the exterior to the interior.

Kuraray, for example, is currently doing a case study on a laminated glass project in a living community built under the Brooklyn Bridge in New York, which utilized the company’s soft PVB interlayer to create an acoustical glazing solution. The glazing was installed in all the doors and windows.

In fact, Kuraray’s Valerie Block says that laminated glass in general—acoustical or otherwise—is proving its worth in the sound arena regardless of whether it was a consideration when the glass was specified.

Another major driver in selecting glazing is whether or not it meets hurricane and other impact requirements. Those standards often call for laminated glass, so by default, end users are already getting a boost in acoustical performance.

“You notice it in Florida and other states with impact glazing,” Block says. “I’m sure those people are absolutely shocked. When they ordered impact glazing, they weren’t thinking at all about acoustics. But laminated glass can provide a variety of benefits.”

From an application standpoint—in terms of structures that intend to dampen sound through glazing—airports still rule the day, whether it’s the terminals themselves or the businesses and homes around them.

The educational sector, Block says, is an area ripe for acoustical glazing given the impact noise can have on learning. However, the way glazing is selected “varies dramatically from one school to the next.”

“It could be based on an architect’s specification, it may come from a master spec, or it may come from the school district, where the school board says beforehand that they want some kind of acoustical glazing,” she says.

Schimmelpenningh adds the heightened awareness of glazing solutions for minimizing room-to-room noise has also sparked an increase in acoustical glazing being used in office settings, “especially with the design trend of more open workspaces.”

And while acoustical performance is not enforced from a broad code standpoint, aside from specific city-by-city requirements, Block says the acknowledgement of acoustical performance in LEED has been a driver in the interest for acoustical glazing.

—Nick St. Denis


The Big Three

While acoustics aren’t anywhere near energy in terms of performance requirements from a codes perspective, designers and owners are recognizing the impact acoustics can have on occupants.

With that in mind, they’re also learning about the range of solutions glass and glazing can provide.

Julia Schimmelpenningh, global architectural applications manager at Eastman Chemical Company, says there are three main areas considered when choosing acoustical glazing. The first is mass (1), as “thicker glass will dampen sound to a certain extent.”

The second is air space (2). “How much air space can you put in an insulating glass unit?” she says, adding that the ability to add more air space in a unit can make a significant difference in acoustical performance. “But not all windows can take a 6-inch air space,” she says.

Then, there are dampening materials (3)—such as an interlayer. “The unique thing about interlayers is they can complement various glass thicknesses and air spaces. Instead of having 6-inch air spaces, you might now only need half that space—or less.”




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