Estudo da eficiência da duplicação de janelas na melhoria do isolamento acústico destes componentes

Abstract

The aim of this research is to evaluate sound insulation behavior of double windows, when a second window is placed upon a previous one, keeping an air layer between them. This was done through standard tests carried out at the reverberation chambers of the Thermo Acoustics Laboratory, of Universidade Federal de Santa Maria in accordance with ISO 140-III, ISO 717-I international norms and the Brazilian Norm Project 02:135.01-001. First, low air hermetic windows were duplicated, each one having Rw = 18 dB. Second, good air hermetic windows were duplicated. The objective, through this technique, was to find out sound insulation improvement of double windows under the two mentioned circumstances. Observing the test results, it was verified that low air hermetic double window obtained Rw = 26 dB, with an increase of 8 dB in relation to just one window of the same typology. Insulation gain, in this case, occurred mainly in medium and high frequencies. In relation to good air hermetic double window, a Rw final of 37 dB was obtained, considering that the increase in sound insulation depends on the initial performance of the fist installed window. The gain in insulation in the second instance was between 4 to 8 dB, mainly in relation to low and medium frequencies. Therefore, it was possible to quantify which sound insulation improvement could be done on façades employing the technique of double windows in order to contribute to the betterment and quality of buildings in Brazil