The ‘acoustic health’ of primary school classrooms in Brisbane, Australia

Purpose: To examine the ‘acoustic health’ of primary school classrooms in Brisbane, Australia. Methods: An acoustic survey was conducted on 33 primary school classrooms in Brisbane, Australia. The classrooms were typical for the region being single cell or dual cells separated by a concertina divider, varying in volume from 69 to 378 m3, and made predominantly from acoustically hard materials. Results: The unoccupied sound levels ranged from 25.7 to 50.0 dB LAeq and reverberation times (RTs) from 0.34 to 1.26 s. This represented a 26% failure rate for unoccupied sound level and 79% failure rate for RTs against Australian Standards for teaching spaces in primary school classrooms. Closer analysis of 12 of the classrooms showed occupied sound levels from 49.8 to 64.8 dB LAeq during quiet activity, and speech transmission indexes (STI) ranging from 0.35 to 0.80 (on a scale of 0–1). This represented a 92% failure rate for occupied sound level and STI against research recommendations for teaching spaces in primary school classrooms in Australia. Conclusions: The high percentage of classrooms returning unsatisfactory acoustic measures supports long-standing and ongoing calls around the world to systematically improve classroom acoustics. We conclude with practical suggestions to mitigate the identified acoustic problems in these classrooms.