In July of 2022, a new version of the Belgian standard NBN S 01-400-1 was released, which outlines acoustic standards for residential buildings. These standards serve as a guide for good practices in the design and construction of residential buildings with planning permit applications submitted after January 1st, 2023. The updated standard reflects the need to adapt acoustic requirements to changing noise levels, particularly in light of the increasing proportion of lightweight construction and the current expectations for acoustic quality.
One significant change in the revised standard is the introduction of three performance levels (Class A, Class B, and Class C), which align with the international classification system ISO/TS 19488. The minimum performance level required by the standard is Class C. For rooms between two different new residential buildings, such as two row houses, Class B performance requirements must be met as a minimum in terms of airborne and impact sound insulation. Additionally, the updated standard includes requirements for frequencies as low as 50 Hz by introducing single-values RA,50 and LI,50.
It is worth noting that cross-laminated timber (CLT) assemblies can provide satisfactory sound insulation, even when the building's structure is left exposed as finishing. In a recent test campaign at Buildwise, different acoustic floor solutions were tested on CLT assemblies while maintaining an appealing wood ceiling. The results demonstrated that it is possible to meet Class B standards for both impact and airborne sound insulation with asymmetric lightweight floor/ceiling setups, keeping the appealing wood ceiling visible. Further details can be found in the technical bulletin or reports available on Stravi-dB.
