Speech intelligibility is critical to the learning that goes on in classrooms every day. To create the best acoustic environment for learning, construction of classrooms should be guided by the ANSI S12.60-2002 standard. The ANSI S12.60 limit for the
one-hour average of background noise level is 35 dB A-weighted which requires the careful control of background noise sources such as:
- HVAC and other building systems
- Equipment: computers, projectors, etc.
- Outdoor noise such as playground noise or traffic
- Corridor noise
- Noise from adjacent classrooms
Reverberation time (measured as RT60, or the time it takes a sound to degrade by 60 dB) also influences speech intelligibility. While some reverberation is pleasant, excessive reverberation can lead to poor intelligibility and decreased learning. Hard,
reflective surfaces and a lack of sound absorbing surfaces can lead to high reverberation and decreased speech intelligibility.
Although all students benefit from good classroom acoustics, some learners are especially susceptible to the negative effects of excessive reverberation and background noise
- Very young children
- Students with hearing impairments or learning disorders
- Students learning in a non-native language
The following is a summary of some of the recommendations found in the standard, ANSI S12.60-2002, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools, and is not meant to replace the full standard. The full standard is
available for purchase through ANSI.
|Table Summary of ANSI S12.60-2002, Acoustical Performance Criteria|
| ||Upper Limit|
|Classroom Size *||< 10,000 ft3||Between 10,000 ft3 and 20,000 ft3||> 20,000 ft3|
|Reverberation Time (RT60)||0.6 s||0.7 s||No limit given|
|Background Noise Levels||35 dBA||35 dBA||40 dBA|
*The levels listed apply to unoccupied classrooms
For More Information on Classroom Acoustics