Parametric Study on the Impact of Volume and Shape on Acoustic Conditions in Atriums Covered by ETFE and Glass

Public atriums which are covered by transparent roof structures and built with sound-reflective surfaces, often suffer from excessive noise and long reverberation times. At present, there is a lack of practical design guidance to help architects address these acoustic challenges in large gathering spaces. This study investigates the effect of the volume, geometry, and transparent roofing materials on the indoor acoustic performance of atrium. Numerical simulations were carried out for atriums with varying plan aspect ratios (1:1, 1:2, 1:3), heights (7.5–30 m), and roof materials (glass, Ethylene Tetrafluoroethylene (ETFE)), evaluating the Reverberation Time (T₃₀) and Speech Transmission Index (STI). The results show that increasing volume leads to longer reverberation times, particularly at low and midrange frequencies, while speech intelligibility generally improves in larger spaces (if they are very reverberant). ETFE roofs achieve shorter reverberation times and higher STI values than do glass roofs, especially in smaller volumes and at lower roof heights. The findings provide a quantitative basis for acoustically informed atrium design and highlight the importance of integrating acoustic expertise at early design stages.