An evaluation of noise reduction performance and VR application for acoustic windows in Hong Kong

Developable land for housing development in Hong Kong is scarce. In order to tackle the challenges on the planning of public housing sites in close proximity to heavily trafficked roads, the latest design of noise mitigation measures in the form of acoustic window for reducing noise penetration to the indoor environment has been considered. To maintaining air ventilation, the acoustic window design consists of an additional window layer in staggering position. The outer window is a push-pull type whilst the inner one is a half-size sliding window. By properly position the openings of inner window with the outer window, the sliding window acts as a "baffle" for screening off noise penetration when it is positioned behind the outer opening. To appraise noise reduction effect of the acoustic window design in residential development projects, an on-site mock-up unit with acoustic window installation was constructed for noise measurements. The noise reduction performance results were found to be promising. To further investigate effect of various parameters such as receiver room size, incidence angles to source line etc. on noise reduction performance, a further study at a testing facility has been conducted. The testing facility has established a controlled environment with loudspeaker as source signal for noise measurement. This paper presents the study approach, mock-up tests and in-situ measurements of the noise reduction performance of the acoustic window under varying parameters. On the other hand, Virtual Reality technology with auralization has been adopted to help architects, engineers, etc. apply the acoustic window in planning residential developments and designing residential unit.