A field study to review sound quality and speech intelligibility in elemantary school buildings

The study aims to investigate the relationship between the acoustics quality and the intelligibility of speech through the analysis performed in a classroom at a primary school located in Istanbul's Küçükçekmece district, under the take-off route of airplanes. In this context, a multitude of methodologies employing surveys, intelligibility tests and measurements were utilized. The intelligibility tests were performed by submitting 60 meaningful and 60 gibberish words to 3rd and 7th grade students, and asking them to fill in the blanks using the words under three distinct acoustics environments. The words were then analyzed under 3 distinct states: the existing conditions characterized by long reverberation and high noise levels; after the first improvement (application of false ceiling and PVC flooring to improve absorption) with shorter reverberation time with still high noise levels; and finally after the second improvement (application of windows with better sound-proofing and wall panels based on glass wool) with less noise and even shorter reverberation. The survey was performed by submitting a questionnaire to 3rd and 7th grade students and their teachers, asking about a number of sources of environmental noise. Different questionnaires were prepared for the students and the teachers. In that context, the study intended to investigate the level of awareness about and the suffering caused by the noise, among the students and the teachers. Furthermore, the study intended to emphasize the differences between the level of suffering caused by airplane and traffic noise, on the students and the teachers. The responses received were collected in a 5-point likert scale from "I don't suffer at all" to "I suffer terribly". In parallel to the test and survey, external noise measurements, field measurements regarding the sound insulation provided by exterior building elements against noise from the air, and reverberation length measurements were taken. The results indicate that current acoustics conditions leave much to be desired in terms of compliance with comfort levels defined in standards, that improvements effected led to a striking improvement in the intelligibility of speech and the acoustics quality of the environment.