Bert Roozen

Measuring the sound insulation of an external thermal insulation composite system (ETICS) by means of vibrometry

The impact of External Thermal Insulation Composite System (ETICS) on acoustic properties of external walls has been already examined. Probably the most fundamental research was carried out in Germany (Weber). The effect of thickness and dynamic stiffness of ETICS, as well as mass of external plaster, on decreasing of wall sound insulation was demonstrated. In this paper, the mass spring mass resonances (m-s-m) were investigated, in case of a massive external wall with ETICS. Application of ETICS increases the sound insulation of walls in the mass-law dominated frequency range by about 12 dB/oct. However, in the low frequencies ETICS decrease sound insulation due to resonant effects, which become very prominent in traffic noise situations. This contribution presents how vibrometry measurements can be useful for ETICS sound insulation properties measurement.

Perceived Loudness of Sound Transmitted through Light Weight and Heavy Weight Walls

When assessing the sound insulation quality of buildings constructions, policy makers and investors typically demand for single number ratings and sound insulation classes that allow for easy ranking of building products. Converting the full frequency content of a precisely measured or calculated structure into a single number, which takes into account all aspects of the insulation performance in a balanced way, is a challenging task. The recently proposed draft standard 717 proposes to take into account also frequencies below 100 Hz. This makes the single value rating even more complicated, since the transmission spectra R (dB) of walls can be qualitatively very different above and below 100 Hz, and even more, since, particularly at low frequencies, human hearing depends not only on frequency but also on the absolute sound level. This article presents a comparison between masonry and light-weight walls with different R value, in terms of the perception of loudness of typical living room, traffic noise and machinery noise transmitted through the walls. The effect of temporal and spectral features of the presented stimuli on loudness perception is analyzed.