Acoustically-designed building façades

Simplified topology for a prediction tool
© Fraunhofer IBP
Simplified topology for a prediction tool for designing sound-absorbing building façades, Immission Points 1 to 9.

Noise pollution in urban areas is particularly a problem in busy areas, such as railroad lines, street canyons or parking areas, and is therefore a current issue. In such areas, noise is reflected by façade elements that are often designed without sound-absorbing properties. Therefore, façades and balconies fitted with sound-absorbing covering offer the potential to reduce sound immission in the surrounding area. However, the surface area of sound-absorbing façade elements required for a specific case cannot be estimated without sufficient expertise. In addition, façade openings, such as those created when windows are opened to air a room, increase noise pollution inside the building. Therefore, acoustically-regulated façade systems also serve to reduce noise pollution indoors.

Project goals

No less than three projects at the Fraunhofer Institute for Building Physics IBP demonstrate ways of designing building façades with acoustics in mind. Sound-absorbing materials for covering façades and balconies, for example, are assumed. In one of the projects, Fraunhofer IBP collaborated with Schüco International KG to study how the effect of façade design on sound immission can be fundamentally estimated during planning using simplified building topologies, with different building dimensions and with varying sound-absorbing effects.

Another way of designing façades with acoustics in mind is to use smart sound insulation on windows. To this end, Fraunhofer IBP is developing a concept for an intelligent window control system that reduces noise pollution inside buildings by taking into account subjective noise assessment and appropriate noise analysis.

Current project status

Among other things, they can absorb incident sound waves. Balcony soffits provide further design space that can be used to absorb sound. Thanks to a prediction tool for building planners developed at Fraunhofer IBP, the effect of such façades on sound immissions in the surrounding area is now easy to assess.

When a window is opened, however, sound also enters a building. This creates a conflict of objectives: the sound insulation is much lower, which is why noise pollution in the interior increases during ventilation. A first approach to counteract this conflict is to automatically control the closing mechanism of the window depending on noise levels. A new approach is based on the evaluation of the character of the noise and thus not only on the measurement of sound pressure levels.

Concept of the smart acoustic window control
© Fraunhofer IBP
Concept of the smart acoustic window control: Noises are analyzed to predict disturbing noise levels and the window is open and shut accordingly.