An acoustic survey of Korean school classrooms: The necessity for Korean acoustic standards and design guideleines

초록

This paper presents the results of a recent noise and acoustic survey conducted in school classrooms in Korea. The objective of the survey was to provide information on the acoustic characteristics of classrooms in Korea and to emphasize the necessity of introducing acoustic standards for classrooms. The survey includes unoccupied data on the acoustic conditions and sound insulation performance in addition to occupied speech and noise levels in 16 classrooms in four schools with a range of student ages. None of the classrooms complied with the background noise level, reverberation time, and airborne sound insulation requirements aa defined in the ANSI and BB93 standards. All eight classrooms were found to meet the impact sound insulation requirements. A Gaussian mixture modelling analysis of the data from all 27 classes in the four schools revealed that the mean speech level was 65.1 dBA (s.d. = 5.2), the mean noise level was 50 dBA (s.d. = 6.1), and the difference between the speech and noise levels was 15.1 dBA (s.d. = 3.3). It was observed that the mean speech levels were higher in elementary school classrooms than in junior high, high, and special school classrooms, with a parallel trend evident in noise levels. The findings indicate a general trend of decreasing noise levels with increasing age of the students and decreasing numbers of students. A significant correlation was observed between speech and student activity noise levels, with a 0.71 dBA increase in speech levels for every 1 dBA in noise levels. Furthermore, the noise levels in the school classrooms were found to be closely related to the type of classroom activity. The predicted T 30 values for occupied conditions showed a statistically significant correlation with the noise levels and SNR values. A significant correlation was observed between the mean noise levels in classrooms and noise levels in corridors, indicating that the management of disruptive noise from adjacent spaces is essential to ensure optimal acoustics for speech in classrooms.

키워드