Acoustic environment of school classrooms in warm-humid climates for better learning

Abstract

Speaking and listening are the two main functions in classrooms and the children should be able to hear and understand what the teacher is speaking to them. This study is the evaluation of classrooms for young children in India, to assess their acoustical environments for better learning. The schools under consideration are located in an educationally advanced locality in India - a district in the southern part of India, namely Kanyakumari. Situated in a warm humid climate, the classrooms have open windows and doors with the possibility of noise intrusion from outside. In this study, depending on the location of the schools and their external surroundings, the schools are classified into three categories: schools located near roads with heavy traffic (Noisy-sites), schools located within Housing sites, schools located in zones far from public roads and away from residences. A total of 120 classrooms in 25 schools in the three categories are studied. Comparison with the national and international standards of background noise and reverberation time was made to assess the acoustic condition in the classrooms. Using available software ClassTalk, the speech intelligibility parameters like, Speech intelligibility, Signal to Noise level difference and Speech Transmission Index in the classrooms was evaluated to assess the acoustical quality of the classrooms. Some of the conclusions from this study are detailed below. It was found that 90 % of classrooms at Quiet sites were in the acceptable range of speech intelligibility and at Housing sites 68 % of the classrooms were acceptable. However, at Noisy sites which are located near highways on public roads, the BN in classrooms in the occupied condition reached about 61.1 dB A and hence only about 28 % of classrooms were acceptable. Some cost effective means to reduce the BN and RT in classrooms were tried and the values were measured and it is established that the speech intelligibility can be improved, by providing floor mat and wall curtain.