Monolithic perforated plasterboards with diffusion and absorption characteristics could enhance the acoustic quality of an office building. However, the acoustic quality of an office also depends on its soundproof level for exterior noise sources, like human voices from adjacent offices or corridors. A soundproofing solution could be very complex to implement if all transmission paths are to be treated. When designing a soundproofing solution for office buildings, all the transmission paths have to be identified and ranked: (1) Direct transmission paths by the main partition between adjacent rooms; (2) Indirect transmission (flanking transmission) by all the lateral transmission paths. Flanking transmission can be minimized if the junctions are well studied and designed. For high level performances, it is safer to propose a full height partition and avoid a continuous ceiling between adjacent offices. For medium, or standard, performances, architects prefer the continuous ceiling solution in order to be able to change office configuration and partition positions later when the floor occupation scheme varies. A series of laboratory tests has been performed with a monolithic perforated plasterboard ceiling. The test results show that perforated plasterboard with a high absorption coefficient has equivalent performs at an equivalent level or with or better performances than standard acoustic ceiling tiles (T bar) with an equivalent absorption coefficient. Light acoustic barriers inside the plenum are already used to enhance soundproof performances, but it is not possible to install them with a monolithic acoustic ceiling. The solution proposed is to close the perforations of the ceiling along the top of the partition: With a 500 mm wide airtight shield on top of the ceiling board (closing the perforations) on each side of the partition, a gain of 3 dB has been observed, and a gain up to 6 dB with a 1000 mm wide airtight shield.
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