Estratégias de redução do ruído de impacto através de intervenções no sistema de forro

Abstract

The ABNT NBR 15575: 2013 Performance Standard was the first national standard to establish minimum acoustic performance criteria for vertical residential buildings in Brazil. After coming into effect, the market has been adapting to improve the behavior of buildings and reach the mandatory levels recommended for airborne sound and impact noise. The floating floor is the most efficient insulation strategy, as it cushions the contactbetween the floor and the rest of the building and prevents the spread of vibrations generated by the impact on the lower floor. This method is applied during the construction phase of the building, is more difficult to execute, in terms of practicality, after the occupation of the property. This work seeks to reduce the problem through intervention only in the noise receiving environment. The studied strategies are applied to the ceiling system, analyzing the potential to reduce impact noise and considering the relationship between performance and cost-benefit. The tests were carried out in the laboratory and four ceiling models were considered: 1 - simple plasterboard ceiling; 2- Simple plasterboard ceiling with bagged glass wool blanket over the plasterboard; 3- plasterboard ceiling with insulation of the connections between the ceiling system, slab and walls; 4 - Plasterboard ceiling with insulation of the connections between the ceiling system, slab and walls with the addition of the bagged glass wool blanket over the plasterboard. The highest insulation gain obtained was 13 dB for the fourth model. However, it resulted in the worst cost-benefit, the most recommended being the conventional plasterboard lining with glass wool blanket in the ceiling (second model), as it was able to isolate 10 dB of impact noise and cost three times less compared to the fourth model. The result confirms the importance of performing acoustic insulation directly in the noise-generating environment to efficiently reduce the sound vibrations transmitted through the links between walls and slabs. The strategies applied to theceiling system can be interesting as an alternative of suitability for dwellings already builtwith noise levels of impact on the floor above that allowed by the current standard