Silent nights disturb Swedish construction industry

New guidelines on exposure to street noise are posing tighter restrictions on the Swedish building industry. One construction firm is designing a new, multi-layered window to insulate its street-side apartments from noise levels breaching regulatory limits.

Swedish guidelines set in 1997, currently being transposed into law, state that residents should be able to sleep with their windows open, and should not experience noise above 55 decibels from the street. Since the guidelines were introduced, some construction companies have had to rethink the design of proposed buildings to be sited on busy streets.

Designers of Stockholm’s trendy new apartment block, known as “the Elephant”, were forced to increase the size of their apartments to ensure they included a ‘silent wall’, where every apartment had a quiet room overlooking a central, internal courtyard.

Another firm has had its work halted mid-construction by the mayor of Stockholm, because the design of its flats, mainly one room apartments half of which overlook a busy street, contravened the noise guidelines. While the firm is appealing the mayor’s decision, another construction company has decided to take a proactive approach by inventing a new, outer-layer window that guarantees silent nights.

“It’s not unreasonable for the law to expect everyone to be able to sleep with their windows open,” Torsten Josephsson told edie, “although how many people actually do?” Nevertheless Joesphsson’s firm, Einer Mattsons Byggnad, is developing a new window that will be added to their nearly completed building in central Stockholm.

The window consists of the traditional, tripling glazing system commonly found in Stockholm, with a fourth external glass window mounted on the outside of the wall. The fourth window is pierced with small holes that allow air, but little noise, in, while noise insulation padding runs along the edges of frame. Thus residents should be able to leave their inner windows open without experiencing excess noise.

The firm don’t yet know how well the design will work, says Josephsson, but they hope to achieve sufficient noise reduction to drop below the 55 decibel limit.

While Stockholm residents enjoy peaceful nights, air traffic controllers at the city’s Arlanda airport are feeling a little queasy – because their control tower sways in the wind. Seven of the sixty strong staff experience nausea when the tower is buffeted by strong, winter winds, and have taken to wearing acupuncture wristbands to overcome the problem. “The good news is that they work,” Traffic Control Chief Pia Johansson told edie. “But the tower is still swaying, and that’s not so good.”

Although the tower sways slightly more than the regulatory standard, the firm that built it says this is not a problem. “When we built the tower we prepared areas for liquid dampeners,” Sven Blomgren told edie “In fact we could have installed the dampeners before the building opened, but this is a costly affair, so we decided to wait and see.”

Blomgren’s firm is now waiting for windy weather to measure the acceleration of the building. “As soon as somebody feels ill, we’ll turn on the equipment,” he says. His firm estimates that around 600 tanks of water, each with a capacity of 35 litres, will need to be placed around the tower to slow its acceleration by 50%. Similar liquid dampening has been used to stabilise tower blocks in Tokyo, says Blomgren.

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