Geometric shapes and classroom acoustical quality: case study at Campinas-SP

Author(s)

Adriana Eloa Bento Amorim

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Civil, Arquitetura e Urbanismo
• Defense date: 2007-08-22

Examining board members

Stelamaris Rolla Bertoli; Doris Catharine Cornelie Knatz Kowaltowski; Luiz Antonio Perrone Ferreira de Brito

• Advisor: Stelamaris Rolla Bertoli

Abstract

Studies about classroom acoustics are developed each time more into the scientific and academic society, due to its influence in the teach-learning. The school¿s environments demand acoustical quality that must be foreseen already during the design planning. Some situations of acoustic not adjusted on classrooms are shown in research that using several methods, generally with application of word¿s rightness and error tests as well as of the analysis and evaluation of parameters as the sound pressure levels and reverberation time. In the State of Sao Paulo the classrooms of public education buildings are projected in accordance with same lines of direction that aim at the school design standardization. Therefore, this work has as objective to identify what geometric shapes are more common on classroom¿s design found in public schools at Campinas-SP, to present the acoustic parameters behavior how much to the speech intelligibility of classrooms and to point the shapes that are most favorable to the acoustical quality for classrooms. It was made classroom¿s cadastral survey for sample definition and after was made architectural survey hers. This procedure allows identifying the number of the rooms more common geometric configurations. The classrooms which have the same configuration standard were selected and analyzed, totalizing seventeen classrooms. The acoustical measurements were made using the impulse response technique of the room and the acoustical parameters were obtained of the room acoustics evaluation software, the DIRAC®, by Brüel & Kjaer. The parameters were derived from the impulse response were analyzed in this work: Reverberation Time (RT), Early Decay Time (EDT), Definition (D50), Speech Transmission Index (STI) and Percentage Articulation Loss of Consonants (%ALCons), for each 1/1 octave frequency band. Also it was analyzed the internal and external background noise or ambiental Equivalent Sound Pressure Level (LAeq), which were measured with sound pressure level meter. Complementary analysis of the form for each room was made by the proportionality of the dimensions, according to Bolt¿s Diagram scale. Among the more common geometric shapes in plant of rooms had found were: the square shaped (7x7m) and rectangular (6x8m). Inside each configuration of classroom had presented different acoustical performances. For the fact to exist a great variety of factors and parameters intervening on classroom acoustics, it was possible to identify some acoustical behaviors trends for geometric configuration (AU)