Plenum window insertion loss in the presence of a line source—A scale model study

Abstract

The acoustical insertion losses of plenum windows installed on a building facade in the presence of a non-parallel line source are studied by using a 1:4 scaled down model in a semi-anechoic chamber in the present investigation. Two types of insertion losses, weighted by the normalized traffic noise spectrum (from the 100 Hz to 5000 Hz one-third octave bands), are defined with different references. The first one is for the case where the orientation of the building facade relative to the line source is fixed. The reference case is the opened window having the same orientation angle as the plenum window. The maximum and minimum insertion losses under this condition across the orientations tested are found to be around 14 dB and 5 dB, respectively. The other is the opposite situation where such orientation is allowed to change because of practical purposes and the reference for this condition is the opened window with its width span parallel to the line source. The corresponding maximum and minimum insertion losses are found to be around 18 dB and 8 dB, respectively. There are evidences showing that the lower order plenum acoustic modes are responsible for the relatively high low frequency insertion loss.

Full scale field study of sound transmission across plenum windows

“…which is equivalent to the one-third octave band noise reduction adopted in Tong and Tang [12] as their receiver room is very reverberant such that the sound absorptions in m 2 Sabine are numerically very close to the room constants.…”

“…Kang and Brocklesby [10] studied the use of thin micro-perforated panels in improving the acoustic protection capacity of the window. Tong and Tang [12] carried out a scale model study on the acoustical performance of the plenum windows. It is found that apart from the window opening size and air gap width, the window's orientation relative to the noise source has great influence on the acoustical protection.…”

A Review on Natural Ventilation-enabling Façade Noise Control Devices for Congested High-Rise Cities

“…It is now commonly referred to as a ventilation window or plenum window [60,61] (hereinafter referred to as plenum window). This device is a double-walled (usually glass panes) plenum structure, with a staggered air inlet and outlet.…”

“…A parametric study on the sound insertion loss of a horizontal type plenum window was carried out by Tong and Tang [61], using 1:4 scale model experiments. The effect of the window orientation, relative to the sound source, θ, was also tested.…”

Acoustical Benefits of Plenum Window as Facade Device – A Parametric Study

“…This staggered inlet and outlet opening window system, referred as plenum window hereafter, has been attracted many researchers as it can provide high sound insulation while allowing natural ventilation across it. Plenum window proved to be effective on providing acoustical protection to the residential buildings compared to the conventional window system [12,13]. In this paper, full scale laboratory measurements were carried out to investigate the effects of various plenum window configuration parameters to the acoustical performance of this facade device.…”