Specially designed window systems for noise reduction - An application in Hong Kong

Like other metropolitan cities, Hong Kong is facing serious environmental noise problems. The Government of Hong Kong is committed to addressing the problems and has adopted proactive actions like preventing the problems through land use planning and environmental impact assessment process, implementation of appropriate mitigation measures on infrastructure projects etc. In most cases, measures like barriers / enclosures would be required. However, as the majority of residents live in high-rise buildings and such a compact urban setting, noise problems are almost unavoidable. To make Hong Kong a livable place with a good acoustic environment, examining other measures on building façade design is necessary. This paper will discuss an example of applying micro-perforated absorbers to a top-hung window system to reduce internal noise level of habitable rooms affected by operation noise from a nearby railway system in a residential development project in Hong Kong. With careful design, a noise reduction of up to 14 dB(A) can be achieved. The approach of applying micro-perforated absorbers (MPA), the preliminary laboratory test and extensive in-situ tests will be included.