STRUCTURAL GLASS FACADES - USC School of Architecture

2.4.3.2 Acoustic Performance: Glass as a Sound Barrier
Glass is an inherently poor acoustical barrier. The acoustic behavior of any wall system, and
perhaps especially of glass wall systems, is emerging as an increasingly predominant issue.
The world may well be getting warmer, but it is most certainly getting noisier. Noise pollution
is a serious problem, especially in major urban environments. The increase in high-rise
condominium projects in the cities has many developers and designers concerned about the
acoustics of these residential spaces.
Façade acoustic design is a function of utilizing the best performing materials for the
frequencies that will be relevant to the architectural purpose. The acoustic considerations for
an airport are different than for a shopping mall, and those equally different for a residence.
Acoustic design is complex. Different materials display varying behavior as a function of the
material properties and the frequency of sound. A sound rating can be determined for a
particular glass type, but the glass is usually incorporated into some kind of framing and/or
support system, and the system as a whole may exhibit quite different acoustic behavior that
the glass in isolation.
Making glass thicker does little to improve its sound transmission loss (STL). In fact, at
certain frequencies thicker glass can actually amplify sound. A more productive strategy is to
use laminated glass (the PVB interlayer had certain sound dampening behavior), insulated
glass, or even better is combinations of the two. Varying the ply-thicknesses of laminated
glass can improve acoustic performance.
By evaluating the STL of various tested products, one can optimize the glass performance
by carefully selecting the product that provides the greatest STL at the range of frequencies
most critical to the building application.
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