Acoustic Design of Swimming Halls

Sammanfattning: The Master thesis considers acoustic design of swimming halls. Focus is put into design solutions affecting the acoustic environment such as walls, absorbents and shape. The basis is gained from literature studies and new information achieved specific for the thesis. Swimming halls are built in a certain way that makes a good acoustic environment hard to achieve. The construction consists of hard surfaces and with large volume which creates a loud environment with lot of echoes. The safety aspect may be harmed by this and it can also cause health problems. The problem is that acoustic solutions are difficult to apply to swimming halls due to climate and function demands, for example the lower parts of the walls being exposed to water and contact. One problem is that acousticians are consulted at a later stage in the project where available solutions are more limited. The acoustic influence is getting more prioritized nowadays which is important in order to achieve a desired acoustic environment. During the thesis persons with great expertise in areas regarding construction of swimming halls, both acousticians and other professionals, are interviewed. Visitors and employees in swimming halls have been consulted with questionnaires and the subjective part of acoustics is gained. Measurements in Hylliebadet in Malmö have been performed as well as simulations of a swimming hall in two versions. Parameters such as reverberation time, sound pressure level, speech intelligibility etc. are investigated as well as the subjective opinion on the acoustic environment in swimming halls. The study presents results showing that the recommended reverberation time is achieved for new swimming halls with absorbents placed on the ceiling and on the walls. It also shows that the acoustic environment is improved by tilting a wall. The background noise is a part of the problem and to reduce this is an important aspect. The speech intelligibility is important for safety reasons and a sufficient level seems hard to achieve. The visitors are satisfied with the environment but the employees are exposed to a work environment that needs to be improved. Solutions suggested are primarily an addition of absorbents, lower ceiling height and one tilted wall. Screens may be useful for educational purposes and water as a sound source should be further investigated. Drains for example causes high background noise and more quiet solutions would improve the acoustic environment and reduce the risk that visitors speak even louder, which creates even more sound. The tools to achieve this are to include an acoustician in the early stage of the project. When acoustic solutions can be suggested before the design is determined the outcome is better and the cost lower. It also avoids the risk for later alterations. The team working with the swimming hall project should have experience from swimming halls and share this. Collaboration between acousticians and architects creates better solutions and reduces the risk for undesired compromises.