Several measures to reduce interior noise are available which also serve other purposes, reducing class size is one of them
In order to
lower sound levels to promote an optimal learning environment.
As discussed rather extensively in the theme noise and acoustics, noise comprises one of the, if not the most important sensory challenge, which is particularly present in schools. This concerns children with normal hearing and of course more so children with more acute hearing and a peculiar interest in certain sounds, which occurred in respectively about 49 and 37% of assessed autistic children. (See the theme sound.)
A relatively large number of recommendations is concerned with noise-reduction, among which three in this chapter of architectural spaces.
Apart from these about interior noise, also those about muted reverberation in school (76) and staircase noise (73).
The two most important sources of interior noise are ventilation, and other climate systems (which should be as silent as possible) and especially noise which is produced by students and teachers.
We mention three remedies against the latter noise source.
The first two are measures which also serve other purposes. One is zoning; see for the whole school recommendation 26 and for the classroom number 30. The other recommendations are subsumed under the theme time-out spaces; see 54 (ones own place) and 57 (sensory suite).
The third measure, which isn’t treated elsewhere, is reduction of class size, which also meets other autistic needs. In the in-depth research by Shield & Dockrell a very strong link was found between sound-levels and class size. A class with 30 students produces twice the noise compared to a class of 18. This makes for an extra argument in favor of small classes. (Incidentally, other things being equal, in a class of 18 the sound standard is still exceeded. See the article for details.)