TABLE OF ABSORPTION COEFFICIENTS
|
|
|
| Nature of Surface |
125 |
250 |
500 |
1000 |
2000 |
4000 |
NRC |
| |
|
| Acoustic tile, rigid mount |
0.2 |
0.4 |
0.7 |
0.8 |
0.6 |
0.4 |
0.51 |
| Acoustic tile, suspended |
0.5 |
0.7 |
0.6 |
0.7 |
0.7 |
0.5 |
0.61 |
| Acoustical plaster |
0.1 |
0.2 |
0.5 |
0.6 |
0.7 |
0.7 |
0.46 |
| Ordinary plaster, on lath |
0.2 |
0.15 |
0.1 |
0.05 |
0.04 |
0.05 |
0.09 |
| Gypsum wallboard, 1/2" on studs |
0.3 |
0.1 |
0.05 |
0.04 |
0.07 |
0.1 |
0.11 |
| Plywood sheet, 1/4" on studs |
0.6 |
0.3 |
0.1 |
0.1 |
0.1 |
0.1 |
0.43 |
| Concrete block, unpainted |
0.4 |
0.4 |
0.3 |
0.3 |
0.4 |
0.3 |
0.70 |
| Concrete block, poured |
0.01 |
0.01 |
0.02 |
0.02 |
0.02 |
0.03 |
0.03 |
| Brick |
0.03 |
0.03 |
0.03 |
0.04 |
0.05 |
0.07 |
0.08 |
| Vinyl tile on concrete |
0.02 |
0.03 |
0.03 |
0.03 |
0.03 |
0.02 |
0.02 |
| Heavy carpet on concrete |
0.02 |
0.06 |
0.15 |
0.4 |
0.6 |
0.6 |
0.30 |
| Heavy carpet on felt backing |
0.1 |
0.3 |
0.4 |
0.5 |
0.6 |
0.7 |
0.43 |
| Platform floor, wooden |
0.4 |
0.3 |
0.2 |
0.2 |
0.15 |
0.1 |
0.22 |
| Ordinary window glass |
0.3 |
0.2 |
0.2 |
0.1 |
0.07 |
0.04 |
0.15 |
| Heavy plate glass |
0.2 |
0.06 |
0.04 |
0.03 |
0.02 |
0.02 |
0.06 |
| Draperies, medium velour |
0.07 |
0.3 |
0.5 |
0.7 |
0.7 |
0.6 |
0.47 |
| Upholstered seating, unoccupied |
0.2 |
0.4 |
0.6 |
0.7 |
0.6 |
0.6 |
0.51 |
| Upholstered seating, occupied |
0.4 |
0.6 |
0.8 |
0.9 |
0.9 |
0.9 |
0.75 |
| Wood seating, unoccupied |
0.02 |
0.03 |
0.03 |
0.06 |
0.06 |
0.05 |
0.04 |
| Wooden pews, occupied |
0.4 |
0.4 |
0.7 |
0.7 |
0.8 |
0.7 |
0.61 |
