Sound absorption

Exfoliated vermiculite has a high open porosity, so the filling out of it characterized by high sound absorption. This property of vermiculite can be used to kill airborne noise in ceilings of buildings.


Acoustic properties of swollen vermiculite depend on the thickness of backfill, the size and shape of its grains, the oscillation frequency of sound.


With the increase in the thickness of vermiculite in filling sound absorption intensity increases, reaching a maximum thickness of 50mm. Only a fine vermiculite optimal thickness of the layer can be considered as 40 mm.

For larger thicknesses, sound-absorbing properties of the backfill are the same or even slightly decrease.

Dependence of sound absorption coefficient of expanded vermiculite from the thickness of the layer:

Type vermiculite Sound absorption coefficient at the frequency of oscillations
1000 Hz and the thickness of the layer in cm
1 2 3 4 5 6 7
Exfoliated vermiculite
fraction 0-10 mm
0,15 0,46 0,58 0,60 0,77 0,70 0,65

Significant impact on the acoustic properties backfill renders their grain composition. Optimum size of grains of vermiculite is 0,3-0,6 mm.


With increasing oscillation frequency sound absorption coefficient of vermiculite and growing at a frequency of 1000 Hz reaches 0,7-0,8, which is significantly above the norm for acoustic materials (0,4).


It should be noted that the volumetric weight of vermiculite, other things being equal, affect the sound absorption coefficient is relatively small. Therefore, for acoustic purposes, you can use vermiculite any grain composition.