Purpose-built sound insulation in CLT framed buildings
The proposed design solutions should be seen as just that - a guide to how walls and floors can be designed to meet acoustic requirements in different applications.
The claimed sound insulation performance of the proposals is well supported by a combination of analytical calculations, mock-up and laboratory measurements, and proven acoustic principles and experience. Nonetheless, there are a variety of factors that can contribute to changes in sound insulation when any of the solutions are applied in a real building, factors that cannot be fully taken into account here, but instead an individual assessment must be made for each proposed object. For example, it is rarely the case that all four walls in a room are of exactly the same type, room sizes and room volumes also have an impact, the attachment of CLT panels with regard to screws, fittings and vibration insulation needs to be taken into account in more detail, and the impact of installations may need to be considered.
The different uses of premises, together with the different sound rating standards, mean that the requirement for sound insulation shows a wide range. Airborne sound insulation ranges from Rw=44 (schools, BBR) to DnT,w,50=60 (residential, class A), while the equivalent for impact sound level is Ln,w=68 (offices, BBR) to LnT,w,50=48 (residential, class A). The wide range of requirements is reflected in the different design principles and dimensioning of the proposed solutions.
Practical experience is lacking for several of the proposed designs. However, there is a need in the industry for elaborate solutions with CLT frames that work acoustically for various local applications. The reported work constitutes a step in this direction, and with future measurement results and experience from real buildings, the design solutions can be confirmed and/or adjusted towards the required sound insulation.
Area: Industrial wood construction
Budget: SEK 380,000
Time: January 2021 - December 2022
Project leader: Fredrik Ljunggren, Luleå University of Technology
Funding: This subproject was funded by TCN.
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