Table 2. Sound absorption coefficients and NRC value for varying the thicknesses
Thickness (mm)
Sound absorption coefficient at frequency (Hz)
NRC
250
500
1,000
2,000
10
0.13
0.23
0.36
0.26
0.24
20
0.23
0.32
0.36
0.29
0.30
30
0.25
0.34
0.38
0.33
0.32
NRC: noise reduction coefficient.