Sound Absorption
Materials may be tested in one of the two reverberation chambers in order to determine how sound absorptive it is. Testing is carried out to AS/ISO 354-2006 "Acoustics - Measurement of Sound Absorption in a Reverberation Room". The data obtained in this measurement is then manipulated in accordance with AS/ISO 11654-2002 "Acoustics - Rating of Sound Absorption - Materials and Systems" in order to determine the sound absorption coefficients.
There are two recognised methods of determining sound absorption, the first is the American Noise Reduction Coefficient (NRC). The second is the International Weighted Sound Absorption Coefficient (αw).
As a guide, the sound absorption coefficients for some typical materials are listed below:
| Typical Materials | 63 | 125 | 250 | 500 | 1000 | 2000 | 4000 | 8000 | NRC |
|---|---|---|---|---|---|---|---|---|---|
| Polyurethane foam 25mm thick |
0.1 | 0.15 | 0.3 | 0.6 | 0.75 | 0.85 | 0.9 | 0.9 | 0.63 |
| Glasswool 30kg/m3 50mm thick |
0.2 | 0.35 | 0.65 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 0.91 |
| Mineral Fibre ceiling tile 16mm thick with 400mm air space above |
0.25 | 0.3 | 0.4 | 0.4 | 0.55 | 0.65 | 0.7 | 0.7 | 0.5 |
The NRC is calculated as the average of the 4 sound absorption coefficients from 250 Hz to 2000 Hz.
Sound absorption testing may be carried out over two hours for a single product. Laboratory hire rates may be negotiated on an hourly rate or for the total number of products to be tested.
Contact Stephen Gauld to discuss your requirements.
