No Sound, No Fury

Increasing Populations Bring More Noise; Proper Glazing Can Help

By Rebecca J. Barnabi

Anyone who has ever been to Guatemala will tell you the city is anything but quiet. The sounds of traffic, street vendors earning a living and residents greeting each other echo throughout the bustling streets. Matt Manning, technical services manager and a LEED green associate with Oldcastle BuildingEnvelope®, will attest to that. He and his wife visited Guatemala, and while at the Marriott Hotel, he opened a window and was overwhelmed by the sounds of the street traffic. But when he closed the window, he heard, well, nothing. “That was my first example of real-world proof [in acoustic glazing],” Manning says. “You can drown out just about anything [if you know what you want to drown out].”

Noise pollution is becoming an increasing concern for urban locations around the world. In fact, the World Health Organization (WHO) just declared it as the third most harmful pollutant for humans. “It’s insane how high it is,” says Julia Schimmelpenningh, technical engagement manager for Eastman Chemical Co. in Orchard, Mass. She says acoustic performance is often an afterthought in building design, though it should be a critical aspect. “Don’t take noise for granted. It really can be detrimental to your health.”

Glazing systems in windows can provide a buffer between the world inside a home, office building, hotel or apartment building, and the world outside.

Between the Glass

When it comes to acoustical glazing, laminated glass is one of the most important components.

Kuraray makes interlayer supplies used in laminated glass, including standard polyvinyl butyral, acoustic polyvinyl butyral and SentryGlas. “Your standard PVB is going to offer some acoustic properties,” says Vaughn Schauss, manager technical consultant located in Houston. However, the acoustic PVB, called Trosifol Sound Control, “will give you even more acoustic control.”

With laminated glass, architects and designers look for impact resistance, and, according to Schauss, if they think they need sound control, they go with acoustical PVB. Interlayers have two possible specifications: Sound Transmission Class (STC), the most common reference, and Outdoor/Indoor Transmission Class (OITC). Schauss says that a single number weighs the frequency of speech on the Weighted Sound Reduction Index. “STC, while historically referenced for all acoustic fenestration applications, is better suited for interior partitions such as classrooms, offices, or meeting rooms,” he says.

OITC is used when architects deal with outside noises, such as trains, airplanes, traffic and construction. Schauss gives the example of a hotel built next to an airport or other noisy venue. Kuraray assisted with building a hotel in Chicago recently by the L Train. “So they were looking at ways to reduce the noise level,” Schauss says. The answer was double laminated insulating glass with sound control PVB.

Acoustic PVB was also used for a recent townhomes project in Brooklyn “because of all the traffic going over the Brooklyn Bridge. You want people to be comfortable in their own house,” Schauss says. In acoustics testing, Schauss says that “acoustic PVB performs much better than standard.” Different thicknesses of glass can also be used.

“For acoustic performance, glazing systems that are captured in a frame tend to work better than [those] not in a frame,” says Casey Mahon, president and CEO of St. Cloud Window located in Sauk Rapids, Minn. Frames provide several benefits: a mass of barriers, air space between barriers and air tightness for the overall assembly of the glass.

Mahon has been in the window systems industry for more than 30 years. He explains that two curtainwalls will not provide the right acoustics because the pressure of those systems defeats the performance of the acoustics. Allowing some air into curtainwalls is helpful, but air is not conducive to good acoustics. St. Cloud Window makes an acoustic curtainwall, but Mahon says the product is more of a window wall. “Noise follows air,” he adds.

“We like glass. I love glass,” Mahon says, noting that glass makes a building’s design. Mahon says St. Cloud mostly uses laminated glass for acoustical performance.

Necessity for Acoustics Control

Acoustical engineers determine what is necessary to eliminate certain sound frequencies. “The thicker the glass gets, the better the STC,” says Manning. A bigger air space between the glass also provides better STC. However, laminated glass is what absorbs sounds, according to Manning. Different types of glazing applications and sealants can also contribute to acoustical performance. For example, Manning says a wet glaze, where a liquid sealant is used, is better for STC than a dry glaze. “However, dry is a lot easier to install and a lot more economical,” he says.

In 1995, Mahon says that, by happenstance, St. Cloud made its first acoustic
windows for schools under construction in the flight path of Minneapolis/St. Paul International Airport. “And we happened to have the perfect window,” he says. Afterward, the company launched acoustical performance products and has 400 tests of acoustical performance on file.

Ron Hull, Kuraray’s director of global high performance products, says clients may have STC requirements they hope to achieve with standard PVB, but find if they use thicker glass or acoustical PVB, they will achieve the best results.

“[Glazing for acoustical performance] is an increasing need in the world because all the good land is gone,” Hull says. The land left in cities is land nobody wanted to build on, such as land next to a highway, train tracks or an airport.”

Another factor increasing the need for glazing systems, Hull says, is stricter noise ordinances in cities for new construction. New York City is leading the way with a minimum requirement for STC and OITC.

Acoustic PVB, of course, costs more than standard PVB, and standard PVB costs more than non-laminated glass. However, Schauss says, that by using higher performance PVB the thickness of the glass can be decreased, and costs can be minimized.

The Sound of the Future

Most of Kuraray’s clients are hotels and hospitality businesses, high-rise residential, schools and also glass interior partitions in office buildings.

“I think the driving force is people want to be comfortable in their homes, offices, cars,” Schauss says. They want “quiet space.” He adds, “Who knows what the future will bring as far as technology and having to reduce acoustics?”

Another benefit, is that acoustical glazing systems can also add security to a home or office. “If someone is trying to break into your home, they’re going to have to work harder to get in,” Mahon says, adding that he has acoustic windows in his basement for security purposes. “It’s becoming an increasingly important consideration.”

St. Cloud’s clients include schools, venues and homes near airports. The education of young children should not be interrupted by outside noise. And the company’s products are more and more needed in high-population areas.

Mahon says that as talk increases around green building and being more environmentally-conscious, humans should also be able to look forward to going to a place away from noise. “I think that acoustics should very much be part of that conversation—for our own well being.”

New York City has been keyed in to reducing interior noise for a long time, and Los Angeles is starting to catch up, Mahon says. “So I think as time goes on more cities will come to see this is an important consideration in building.”

Manning lives in California where building codes are increasingly requiring acoustical performance and agrees.

“As far as your work environment, [acoustical performance] gets a lot better,” he says, adding that acoustical performance will continue to be required in more and more construction projects, as building codes lean more toward the use of STC.

Manning says he has seen a lot of evolution in glazing systems and acoustical performance in his 20 years and he looks forward to the next 20 years. “The next 20 are going to be probably even more mind-blowing as far as energy, acoustics. Yes, it’s only going to grow from here. I anticipate our interlayer suppliers are going to make further breakthroughs,” Manning says.

The need for acoustical performance in glazing systems is not going anywhere as long as humans have a need for quiet spaces. “I think as the population density continues to increase, certainly we’re living closer and closer together,” says Schimmelpenningh. She adds the demand for acoustical performance began increasing 15 years ago, and even more in the last 10 years. “As we continue to grow as a society we’re going to see [more demand for acoustics].”

Schimmelpenningh says that WHO’s noise pollution declaration refers not only to the damage noise can do to human hearing, but the health issues created in the body as a response to noise. “We don’t necessarily get used to noise,” she says. Humans react to noise whether they realize they have a reaction or not. Schimmelpenningh uses the ringing of a cell phone as an example. People react in some way when their cell phones ring or receive a text message. This reaction is part of our fight or flight mechanism. Is that sound a danger or not?

Noise is everywhere—in the city with car horns blaring and in the country with the breeze blowing through the trees. That’s likely to continue as the human population grows. The good news is glazing systems exist to encourage the abatement of noise.

Rebecca Barnabi is a special projects editor for USGlass magazine. Contact her at rbarnabi@glass.com.

To view the laid-in version of this article in our digital edition, CLICK HERE.

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