Effect of facade shape for the acoustic protection of buildings

Façade sound insulation can be improved by using high performance components or by modifying the shape of the façade. In many cases, when high acoustic insulation levels are required, the use of high performance components cannot be sufficient, for technical or economic reasons. The European standard EN 12354-3 gives a simplified method to estimate the influence of the façade shape in the reduction of sound power level at the outside of the building envelope. In particular, the influence of the façade is evaluated for a number of building typologies as a function of the general direction of the incoming sound and of the acoustic absorption coefficient of the surface of the underside of any balcony. In the paper the results of a study on the influence of the façade shape on the incoming sound is evaluated with reference to a great number of different typologies of buildings facades. The study has been carried out by means of a prediction software based on the modified theory of the ray tracing (pyramid tracing). With reference to a typical urban configuration, results are expressed as level difference between the simple plane façade and the façade with different kind of shielding.