Modern cities are often too loud. This is not only due to road traffic and aircraft noise, but also to the reflective behaviour of buildings. Sustainably planned facades can help here. A Frankfurt professor has been working on the subject for six years and is calling for a rethink.

Health research has long known that noise makes people ill. The German Federal Environment Agency considers chronic noise stress to be one of the most important triggers of civilisation diseases. Numerous protective systems such as insulating panels or appropriate room furnishings help against noise in buildings, offices and homes. However, the control of noise is also highly relevant for public spaces and plays an important role in the construction industry and the real estate sector. Environmental noise has a direct impact on rents and thus on the social mix of an urban district. If a critical noise level is exceeded, this often leads to depreciation of a property and thus to direct economic damage.

But how can architects and planners reduce the constant noise level in cities? Or in residential areas not far from railway facilities and airports?

Research on noise reduction

“Quieter cities are possible through the targeted implementation of acoustically effective facades in building projects,” says Prof. Dr. Holger Techen from the Frankfurt University Of Applied Sciences. The fact that, for example, surface materials or structural arrangement have an influence on noise distribution is well known and already taught. However, it is difficult to operationalize how the reflection behaviour of facades works in complex urban situations. So far, mainly two-dimensional simulations for buildings of up to eight storeys exist. Techen and his team, on the other hand, tested five mobile facade structures at eight locations in Frankfurt, including for higher buildings.

“Folds, distortions and structural differences – all these have a significant effect on the acoustic reflection behaviour of a facade,” says Techen after the evaluation. A reduction of up to 4 dB(A) can be achieved. The perfect noise-reducing façade must always be designed for the individual location and uses textures or structures. Since the angles at which sound enters and exits the building are decisive, the volume, cubature and compass direction of buildings can also be optimized, especially in relation to a specific noise source, such as an airport.

Individual processes for sustainably planned facades

However, since neighbouring buildings are of high importance, Techen does not want to set standard specifications for sustainably planned facades. Instead, he proposes an individualized process: “In the future, planning teams should start by creating an acoustic profile of the location and then include noise reduction in the design of the building.

One way to promote noise-optimized façade planning is through building certifications that reward these qualities. Our head of certification, Dr. Stephan Anders, is very interested in Techen’s research: “In the DGNB system for neighbourhoods, the effects of measures taken on facades are already being measured. For example, we evaluate the noise at a central public open space. In the case of buildings, we look at the sound insulation in the building and the noise potential of individual devices. It would be exciting to strengthen these areas in the future.”

Potential for all involved

However, Techen also sees great potential for the topic in the entire industry and among all the players involved: “Architects, administration and political decision-makers must address the issue. During the intensive current building activity and the post-densification of our cities, sustainable urban design can be guaranteed right from the planning stage”.

Prof. Techen’s publication, including statistics and graphics, can be downloaded here.