Comparison between Predictive and Measurement Methods of Speech Intelligibility for Educational Rooms of Different Sizes with and without HVAC Systems

Heating ventilation and air conditioning (HVAC) systems represent one of the main noise sources inside classrooms. This explain why HVAC require careful design, competent installation balancing, regular maintenance. Many factors influence classroom acoustical such as handlers or fans, velocity classroom, well size treatment ducts, returns, diffusers. Acoustic parameters, including background-noise levels, reverberation time, intelligibility, were analyzed in 17 classrooms at Università Politecnica Marche region. The study intelligibility was performed by measuring objective parameters situ using prediction methods to determine score. relationship between speech measurements calculation has been studied. STI values with levels time also research shows that a comparison predictive measurement results for different sizes without systems. current method calculating voice transmission index (STI), proposed national international standards, used scores show tool computational robustness allowing its use preliminary evaluations design optimal type school buildings, sound amplification comply Italian regulations.