Speech interference and transmission on residential balconies with road traffic noise

Abstract

Balcony acoustic treatments can mitigate the effects of community road traffic noise. To further investigate, a theoretical study into the effects of balcony acoustic treatment combinations on speech interference and transmission is conducted for various street geometries. Nine different balcony types are investigated using a combined specular and diffuse reflection computer model. Diffusion in the model is calculated using the radiosity technique. The balcony types include a standard balcony with or without a ceiling and with various combinations of parapet, ceiling absorption and ceiling shield. A total of 70 balcony and street geometrical configurations are analyzed with each balcony type, resulting in 630 scenarios. In each scenario the reverberation time, speech interference level (SIL) and speech transmission index (STI) are calculated. These indicators are compared to determine trends based on the effects of propagation path, inclusion of opposite buildings and difference with a reference position outside the balcony. The results demonstrate trends in SIL and STI with different balcony types. It is found that an acoustically treated balcony reduces speech interference. A parapet provides the largest improvement, followed by absorption on the ceiling. The largest reductions in speech interference arise when a combination of balcony acoustic treatments are applied.

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

“…However, reverberation within the street canyons of a high-rise city will largely erase the acoustical protection of the balconies. Nash et al [54] further illustrated that there would be a drop in speech intelligibility inside the balcony of a high-rise building located within a street canyon, after the installation of sound absorption.…”

Insertion losses of balconies on a building façade and the underlying wave interactions

“…El-Dien 12 studied the combined effect of façade and balcony orientation on noise reduction. Naish et al 13 investigated the speech interference levels on balconies affected by road traffic noise. For the improved design of noise-mitigation measures, it is important to understand the acoustical performance of a balcony on a building façade.…”