Noise Control

Increasing Occupant Comfort with Acoustical Glazing

By Jordan Scott

Occupant comfort and wellness is on the forefront of any architect’s minds when designing a building. Providing access to daylighting and views is vital to occupant health, which means many architects turn to glass. For buildings near busy streets, airports and other noisy locations, this could mean that occupants are exposed to noise pollution. Thanks to advances in technology, often involving polyvinyl butyral (PVB) interlayers, acoustical glazing can give occupants access to views while maintaining quiet and comfort.

Recent projects that include acoustic glazing can be found in Milan, Italy, and Crosby, Texas.

Amazon Italy Headquarters

Milan, Italy

GBPA Architects transformed the iconic Tecnimont Headquarters, built in the 1970s in Via Monte Grappa, Milan, Italy, into Amazon’s new Italian headquarters with a transparent glass façade that improves natural lighting and blocks sound. The Milan-based architect refurbished the former building’s dark, heavy cladding with a glass façade using approximately 107,639 square feet of Isolar Solarlux solar control glass, anodized aluminum and various Saflex PVB interlayers from Eastman Chemical Co., located in Kingsport, Tenn.

The solar control façade provides natural day-lighting while maintaining a quiet environment through the use of low-iron laminated glass that combines acoustic interlayers with conventional PVB interlayers. This creates overlap between the indoor and outdoor spaces without compromising occupant comfort.

According to Wim Stevels, architectural industry support specialist with Eastman Chemical BV, the project is located between the historic city center and one of the major railway stations in Milan, wedged at an intersection between two busy Milan roads with high density urban noise.

“Specifically, two tram stops are present directly opposite one of the major façades providing high intensity peak noise as trams break and accelerate,” he says.

Tvitec, based in León, Spain, selected Saflex DG Structural PVB for the 1,100 integrated shading glass fins because of its edge stability and compatibility with print, thereby reducing the risk of delamination. The silkscreen printing on the fins provides decoration as well as shading.

“The exterior fins are a key design element for the building, but also functional in providing additional solar shading for the windows and reducing glare, with limited impact on view-out in the orthogonal direction or limiting daylight,” says Stevels. “The latter is important for LEED certification. With the high exposed edge to surface ratio in the aggressive urban climate (pollution) and the variety provided by the Northern Italian climate (hot summer/freeze-thaw cycles in winter), there were concerns over the edge stability of the interlayer. Eastman was approached to provide an interlayer solution that showed markedly improved edge stability over conventional PVB, while still being compatible with the intricate frit pattern on the fins.”

Achieving edge stability in a configuration that features tempered laminated glass with screen printing, a high aspect ratio, and all edges open requires not only excellent starting materials, but also very good lamination capabilities, according to Stevels.

“Fortunately, our Spanish lamination partner Tvitec is very capable in this respect,” he adds.

For the project, 3,000 units of Isolar Solarlux superneutral with 10-mm thermally tempered coated glass were used on the outside, and 88.4 laminated glass with acoustic interlayers was used for the inside.

The International Union of Operating Engineers (IUOE) has built a hands-on training campus near Houston so that operator engineers can master the latest technologies and proper use of new equipment. The 12,380-square-foot central plant building is where the IUOE “trains the trainers” in heavy machinery and regular maintenance of mechanical systems. One chiller can be taken off-line for training purposes. It’s located in a classroom designed so that trainers can see inside the central plant. Winco Window’s 3385 Fixed Acoustic windows were installed so students can observe operations while receiving instruction in a quiet space. Haley-Greer Inc., located in Dallas, was the glazing contractor.

“The central plant building is the jewel of the center,” says lead architect David Prickett of Carlile Coatsworth Architects based in Irvine, Calif. “Winco’s acoustic windows were selected for their sound proofing properties — a necessity as the class-rooms are adjacent to mechanical equipment and other outside noises from heavy equipment.”

The IUOE Training and Conference Center is expected to bring relief to manufacturing companies needing skilled workers throughout the U.S. and Canada. Prior to its construction, union members relied on suppliers to help them learn about new equipment. Now a maximum of 220 members are able to train together at one, all-inclusive facility.

What Is Laminated Glass?

Laminated glass is created when an interlayer is placed between two lites of glass and then bonded to the glass through heat and pressure. This interlayer causes the glass to become stronger and more durable. It also can hold broken glass in place because the broken glass will adhere to the interlayer, making it ideal for safety, security and hurricane applications.

For projects requiring acoustical glazing, laminated glass is often the preferred choice. A soft interlayer can dampen sound, mitigating noise pollution from the outside. Using thicker glass or multiple interlayers can provide a higher degree of noise mitigation.

There are several different types of interlayers avail-able. One of the most common is made from polyvinyl butyrate (PVB). It is available in a variety of colors and thicknesses, but requires a special climate-controlled environment. Ethylene vinyl acetate (EVA) does not required any special climate controls in the fabrication process, but is more expensive than PVB.

Glass-clad polycarbonate is another interlayer option that provides added blast- and bullet-resistance. Its make-up consists of layers of glass, urethane and polycarbonate, and the laminating process is the same as the PVB process. However, exterior use is not recommended due to the expansion differential between the components. Structural interlayers are much stiffer than traditional PVB and work well in applications requiring specific load requirements such as railings.

Poured Resin interlayers can be used in the same applications as PVB, but the process of making laminated glass is more labor intensive.

Jordan Scott is the editor of Architects Guide to Glass & Metal. She can be reached at jscott@glass.com.

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