According to the Acoustical Society of America, up to 25% of the information can be missed in many classrooms in the United States because of excessive noise and reverberation. ANSI Standard S12.60 for Classroom Acoustics addresses the issues of both reverberation time and background noise and their effect on speech intelligibility by placing maximum permissible levels on each.
Under the new standard, the maximum reverberation time in an unoccupied, furnished classroom with a volume under 10,000 cubic feet is 0.6 seconds, and 0.7 seconds for a classroom between 10,000 and 20,000 cubic feet. The maximum level of background noise allowed in the same classroom is 35 decibels (dBA).
The standard’s acoustical performance criteria and design requirements apply during the design and construction of all new classrooms or learning spaces of small-to-moderate size, and, as far as is practical, to the design and reconstruction of renovated spaces. While this ANSI standard is currently voluntary, unless referenced by a code, ordinance or regulation, school systems would be advised to require compliance with the standard as part of their construction documents for new schools.