A Simulation-Based Approach to Assess and Support Acoustic Characterization and Desing in Classrooms

Students’ learning performance can be strongly impacted by the environmental quality of classrooms. The acoustic quality is one of the most important features, due to the direct effect on the tasks, and impact on stress and fatigue, alone or in combination with other environmental factors affecting thermal, visual and air quality.

Discomfort in one or more of the considered domains can trigger behavioral actions, such as opening or closing windows, operating shades, turning on/off lights, etc. affecting the sensation or satisfaction in other domains, which need to be understood.

Adaptation actions can have a different impact on the students, depending on their position, which exposes them to a different combination of environmental parameters.

This study relies on calibrated building simulation to virtually extend the measurement network and assess objective-subjective acoustic comfort in a naturally ventilated secondary school located near Rome.

This study explores the possibility of applying acoustic simulation to assess the characteristics and conditions impacting acoustic perception and comfort in classrooms.

The model has been implemented in Odeon Room Acoustic Software, and materials properties have been calibrated in order to minimize the difference between the monitored Reverberation Time (RT), Early Decay Time (EDT) and Clarity (C50).

The acoustic quality is investigated considering different room conditions, such as windows and door opening, presence of external noise sources, teacher voice features, background noise by internal activities, in relation to the position in the classroom.

To calibrate and validate the models of different classrooms of the high school, long-term and short-term field campaigns were carried out during the two-year period 2020-2022.

During the monitoring period right-now-right-here subjective questionnaires were administered to gathered acoustic perception and comfort: 825 responses were collected in 50 different conditions. Long term monitoring was conducted on some reference classrooms and the outdoor environment.

The calibrated model allows estimating the equivalent sound pressure level distribution, for a fixed sound source. From the SPL at each desk, the acoustic sensation vote has been calculated through a correlation obtained in a previous study. Finally predicted and actual sensation votes have been compared and a confidence level is established. A deeper understanding of the relationship between the subjective evaluation and the position of the student, and to extend the evaluation to different scenarios is then possible.

The calibrated model is intended to allow the maximization of the percentage of points in the classroom in comfort conditions, through different behavioral actions or retrofit measures.