Mitigation of noise in nursery school classrooms by sound absorption: a yearly noise measurement with different absorbing conditions in actual classrooms

摘要

Acoustic environment in nursery schools have been less discussed than those in elementary schools or junior high schools, and, in Japan, there are no standards or guidelines at present for acoustic planning of pre-school classrooms. There are several studies, however, indicating that the acoustic environment in nursery schools can be harmful to physical and mental health of children and teachers. Waye et al. (2010) reported that the average individual exposure level of children was 84 dB (L_(Aeq)) during the active time period in the play hall or kitchen. Grebennikov (2006) pointed out that teachers' exposure level were up to 85 dB (L_(Aeq)) during the six-hour work time. For the mitigation of these noisy situations of the indoor acoustic environment, sound absorption is considered to be a possible solution, and the present study aims to examine this effect. For this purpose, in the previous study (Kawai 2010), we carried out a field experiment in which sound absorbing boards were installed in the classrooms of an actual nursery school, and found the possibility of the effectiveness of sound absorption. In this study, we conducted the second experiment to ensure the evidence with more comparable condition settings.