Avaliação do isolamento do ruído de impacto em baixas frequências de pisos de edifícios

Abstract

The objective of this study is to evaluate the sound pressure level generated by different kinds of sound impact sources in buildings at frequencies between 80 - 400 Hz using different combinations of flooring and resilient material inside floating floors. Although there exists international and national standards and researches, the researchers have not been able to minimize the problem caused at low frequencies (kids jumping, falling objects, dragging furniture). Thus, it is the assessment of impact noise at low frequencies an interesting subject. Whereas different noise sources generate different impact excitation spectra which, in turn, are more or less representative of the real situation, measurements were made in the laboratory of acoustics UFSM with three sources of noise impact (two standard: tapping machine and modified tapping machine and non-standard: pear 5 kg) three types of floor (slab "bone", ceramic and laminated), two resilient materials (glass wool and EVA) and four sound source positions. The measurement task was divided into two stages with 12 or 4 microphone positions. However for question of analysis the data were divided into 12, 4 and 16 microphone positions. After data analysis it was concluded that the standard sources perform differently depending on the type of resilient material used, but the non-standard source s results differ by the type of flooring used without resilient material. The measurements with both 12 and 16 points microphone, following the same results configuration, but have significant differences with 4. It is evident, then, that the possibility of waiving the additional procedure of Annex A of ISO 10140-4:2010 is true. Another important consideration is that the data has a non-normal distribution, what proves that mean calculations should not be used, contrary to what being done to data in calculations of Ln, Li,Fmax and Ln,global. However when analyzing the data according to the calculated median for standard sources, it was observed that the values have no expressive difference compared to calculated on the average, not being necessary for this kind of excitation using the median. On the other hand, to the source non-standard values showed no persuasive value, which shows that for this type of acoustic excitation is necessary to use the median. But there relevant differences in the results obtained from the measurements with 12 and 16 microphone positions calculated according to the median.