What is it about?

From data logged over 6 full school days in each of 220 occupied K-12 classrooms, we have extracted what the typical speech and non-speech levels were, as well as the signal-to-noise ratios that students experienced in their classrooms. We also have identified how often speech occurred in those classrooms, differences across grades, and how often speech and non-speech levels exceeded certain values.

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Why is it important?

ANSI S12.60 "Acoustical Performance Criteria, Design Requirements, And Guidelines For Schools, Part 1: Permanent Schools" recommends that signal-to-noise ratios in classrooms be at least 15 dB; that is, the desired signal (speech) should be at least 15 dB higher in level than the ambient noise in the occupied room (non-speech). This paper presents measured data taken during multiple occupied school days from each of 220 K-12 classrooms, and reports that 27% of the classrooms in the sample did not meet that requirement.


We are grateful to the US Environmental Protection Agency for sponsoring this work, and to our community partners who were instrumental to the success of this project. Please visit https://engineering.unl.edu/healthy-schools to learn more.

Dr. Lily M Wang
University of Nebraska System

Read the Original

This page is a summary of: Speech and noise levels measured in occupied K–12 classrooms, The Journal of the Acoustical Society of America, August 2021, Acoustical Society of America (ASA),
DOI: 10.1121/10.0005815.
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