Quantifying corridor induced noise transfer in school classrooms: A field-based approach

Excessive classroom noise in schools is attributed not just to external sources but also to internal planning, especially in circulation spaces like corridors, where student activities and movement prevail. The existing acoustic standards limiting such background noise are not quantified, particularly in the scenario of noise transfer from corridors into classrooms under occupied conditions. This study quantifies corridor induced noise transfer into classrooms of schools during occupied conditions and develops a predictive framework based on architectural parameters. Hence, in this work, noise transfer induced in school classrooms due to corridor is quantified through classroom-corridor noise difference (ΔL Aeq ). A total of 19 schools, resulting in 341 paired corridor-classroom field measurements, with varying corridor typologies, spatial configurations, and floor levels are conducted. ΔL Aeq is assessed with focus on corridor typology, presence of openings on corridor-facing classroom walls, corridor geometry, floor level, and courtyard area using correlation analysis, inferential tests, and principal component analysis. Subsequently, ΔL Aeq is formalised into a Classroom Noise Transfer Index (CNTI). Architectural parameters based predictive model (regression) is proposed and cross-validated, with a root mean square error of 2.45 dBA, implying prediction accuracy well within acceptable limits for occupied school conditions, which are naturally ventilated. The gap between compliance-based acoustic criteria and descriptive noise surveys is bridged by the proposed framework, which also provides a practical tool for predicting and mitigating corridor-induced noise in school classrooms.