This is a legacy version of the WELL Building Standard. Please check the latest version here.

Reverberation time

Reverberation time


To help maintain comfortable sound levels by limiting reverberation times.


Reverberation time, or RT60, is a metric which describes the length of time taken for a sound to decay by 60 dB from its original level. Optimal reverberation times vary depending on room volume, intended use of the space and the frequency of transmitted sound. In spaces with high reverberation times, the sounds of voices and footsteps take longer to dissipate, contributing to higher levels of ambient noise. The noise produced by reverberation can decrease speech intelligibility and in some situations cause additional stress. This performance specification can be met through the use of sound-absorbing materials on various surface and design elements.

Part 1
Reverberation Time

The following spaces have maximum reverberation time (RT60) as described:
Conference rooms: 0.6 seconds.
Open workspaces: 0.5 seconds.

Part 2
Reverberation Time for Learning Spaces

Reverberation time measurements for learning spaces meet the following criteria:
Spaces less than or equal to 280 m³ [10,000 ft³]: less than 0.6 seconds.
Spaces greater than 280 m³ [10,000 ft³] and equal to or less than 570 m³ [20,000 ft³] : less than 0.7 seconds.