Clay hollow brick walls are still popular in building industry, but the prediction of their sound insulation properties is not straightforward due to their inhomogeneous and anisotropic characteristics. In this article, a classic approach has been used to determine the sound transmission coefficient of brick walls, assuming an orthotropic behaviour and deriving the mechanical and dynamic characteristics from datasheet information. Different types of walls with horizontal and vertical mortar joints have been analysed. Experimental measurements of the sound reduction index carried out according to ISO 10140-2 standard have been performed, and the resulting values are compared with the predictions in the proposed model. It was found that the sound reduction index can be fairly predicted in the low-frequency range and it is correctly predicted in the mass law region, whereas in the high-frequency range the inner block structure is responsible for a loss of performance which is difficult to predict with the analytical methods.

Estimation of the impact sound insulation of horizontal partitions, evaluated from the performance of basic components according to EN 12354-2, does not provide satisfactory results when applied to floors made of Cross-Laminated Timber (CLT) elements. One of the most interesting reasons for this limited match between predicted and measured impact noise values is the difficulty of correlating the reduction of the impact sound pressure level of the floor covering, measured in a laboratory on a concrete slab, with the actual behavior on a bare CLT floor. Reported here are the results of laboratory evaluations, independently carried out by various researchers on similar CLT structures. The purpose of this study is to identify the empirical spectrum of the normalized impact sound pressure level of a reference floor made according to CLT technology, to provide a simple and useful tool for estimating the noise insulation performances of this type of building element.

Composite panels are being increasingly used in many applications because they can combine several interesting properties, such as high load-bearing capacity, low weight, and excellent thermal insulation. Different core materials can be used for composite sandwich panels, like polystyrene, mineral wool, polyurethane, glass wool, or rigid phenolic foam, which is considered the rigid plastic foam with the best fire-proof properties. During the research and development phase, the use of simulation tools is often required for the improvement of the mechanical behavior of the material. The aim of the paper is to characterize some vibro-acoustic parameters of a sandwich material with phenolic open-cell foam core. The sound transmission loss of the structure is calculated based on its flexural behavior, represented through a frequency-dependent “apparent” bending stiffness which is estimated by natural frequency vibration tests on beam specimens. The comparison between sound transmission loss predictions and measurements in sound transmission suites according to ISO 10140-2 is presented and discussed. Finally, the early-stage prediction potentiality of the mathematical model is investigated when only nominal information is available on the constituent layers, showing that particular attention should be paid to the modifications introduced by the manufacturing process.

Cross-Laminated Timber (CLT) is a building technology that is becoming increasingly popular due to its sustainable and eco-friendly nature, as well as its availability. Nevertheless, CLT presents some challenges, especially in terms of impact noise and airborne sound insulation. For this reason, many studies focus on the vibro-acoustic behavior of CLT building elements, to understand their performance, advantages and limitations. In this paper, a 200 mm CLT floor has been characterized in the laboratory, according to ISO standards, by three noise sources: dodecahedron, standard tapping machine and rubber ball. In order to understand the vibro-acoustic behavior of the CLT floor, measurements through the analysis of sound pressure levels and velocity levels, measured by dedicated sensors, were performed. Analysis was carried out in order to understand what is prescribed by the prediction methods available in the literature and by the simulation software. Then, a specific prediction law for the CLT floor under investigation was derived. Finally, an analysis on sound radiation index is provided to complete the vibro-acoustic study.