The large number of measurements we have performed in recent years with a fixed test rig set-up has allowed us to collect a significant data volume. This data collection has enable us to identify some important trends which apply to Elascon structures. As a rule, the pure timber+concrete structure based on our concrete recipe Elascon Floor C 25/30 F 6.5 G 8 LVB leads to an improvement in the structure-borne sound attenuation of between 3 and 6 dB relative to the previously measured sound starting level. With further de-coupling measures which should provide a stiffness of S/ >= 20 Meganewton per cubic metre, the structure borne sound pressure level is improved further.
Rule of thumb: by increasing the dynamic stiffness progressively in steps of 10 Meganewton per cubic metre, the normal sound level is decreased by 2 dB. However, timbered ceilings are so inhomogeneous and their structure varies so much that a mathematical determination can only be performed with difficulty or not at all. Notwithstanding these reservations, our forecasting model still provides a sound basis for the further design approach.
In principle, suspended ceiling structures should be designed in such a way that the lowest possible resonance frequency is produced. As a rule, if decoupling is employed, the sound attenuation increases distinctly above the resonance frequency. Consequently, the resonance frequency should be kept below the acoustic frequency range of the building structure. The ideal target resonance frequency is a value of < 50 Hertz. The lower frequencies can be achieved by increasing the gap between walls and by increasing the mass of the shell. In the case of critical considerations involving limit values or interacting parameters, we recommend a review with our external sound insulation expert of the structural physics of the building. The large number of measurements from previously completed projects with greatly varying structural characteristics enable us to provide you with professional support at an early stage of your project. Elasco(R)Loft, our recent, innovative development is proof of the potential that can be realised with our Elascon timber+concrete composite structure, especially in the area of sound insulation.
Elascon Flüsterloop for the decoupling of structure-borne sound