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By Sara Hart

Airspace prevents what is called “coincidence decoupling,” where the two lites of glass in an insulated window vibrate together at a certain frequency. This tandem movement reduces the amount of sound that can be blocked at that frequency of vibration. Using a heavy glass and a large airspace between the glass usually eliminates this problem, which is not an issue in this case due to the depth of the windows.

An additional challenge was presented by the zoning code requiring natural ventilation. To accommodate this requirement, the window assembly has a trickle vent—an adjustable opening to provide controllable background ventilation. The vent conducts air along a lined path so as not also to transmit noise. SM&W recommended installing STC (sound transmission class) 56 windows on floors three through nine on the east and south facades. The developer, however, chose an even more conservative route and used them throughout the building at every floor.

 

The Southern California Institute of Architecture (SCI-Arc) in Los Angeles commissioned Hodgetts + Fung Design and Architecture to improve the acoustic quality of the school’s main space (above). With the clever use of modest, low-tech materials—including aluminum tubes, nylon thread, and industrial-weight wool felt—the architects transformed the space visually as well as acoustically (below). Photography: Courtesy Hodgetts + Fung

The overall construction consists of pre-engineered brick-and-metal panels mounted on a stud system. For the walls to conform to the engineer’s noise-reduction criteria, two layers of gypsum wall board were required on both sides of the exterior walls, with additional insulation in the cavity (see wall section, page 144).

The noise problem is not specific to New York, of course. The Mandarin Oriental Hotel in Washington, D.C., designed by BBG-BBGM Architects, also working with SM&W, was built on the last piece of available real estate in Southwest Washington. The aerial panorama (page 145) suggests an ideal location with views across the Tidal Basin to the Jefferson Memorial and easy access to the Mall and Capitol. However, from this perspective, the eye can easily edit out the nearby freight-train line, which also carries commuter trains, and the major freeway that borders the site. It also doesn’t reveal the fact that the site is on the flight path of Ronald Reagan National Airport, as well as a heavily traveled helicopter route.