Triple-layer membrane structures: Sound insulation performance and practical solutions

This report describes a Master’s Thesis research that has been carried out to gain insight in the possible improvements of sound insulation of membrane structures, which are used in practice for temporary structures, e.g. festival tents, and to give practical solutions. This research concentrated on triple-leaf membrane systems with filled cavities. From a state-of-the-art review can be concluded that triple-leaf membrane systems, when filled, perform better than double-leaf and single-leaf membrane structures. From literature research it was concluded as well that tension in the membrane has a negligible effect on the sound insulation and that, on the other hand the flow resistance both of the filling and of the membrane material has large influence. Three different kind of filling materials were used in the present study: (lightweight) glass wool, polyester wool and aerogel. Acoustical measurements were carried out in a laboratory, of which the outcomes were compared to a number of computer and mathematical models. The Multiple Layer Model appears to give good prediction for filled triple-layer membrane systems and this model therefore was used to optimise the important parameters. A well performing triple-layer membrane system was discussed, which met the restriction of 7kg/m2 for the surface density of the membrane package. This system includes one layer of aerogel for reasonable sound insulation at low frequencies, and one thicker layer of glass wool yielding good sound insulation at higher frequencies. This system is only investigated theoretically for nog and not empirically (yet). Details have been worked out for a number of practical membrane structure applications for this result (also applicable to variants using only glass wool), focussing on temporary (festival) tent structures.Building PhysicsBuilding EngineeringCivil Engineering and Geoscience