What is the difference between NRC and SAA?
The Noise Reduction Coefficient (NRC) and Sound Absorption Average (SAA) values are both single number ratings that indicate the level of sound absorption provided by the product being tested. The NRC value is the average of the sound absorption coefficients at four 1/3 octave frequencies (250, 500, 1000 and 2000 hertz). The SAA value is the average of the sound absorption coefficients at twelve 1/3 octave frequencies ranging from 200 to 2500 hertz. The NRC value is rounded off the nearest 0.05 increment. The SAA value is rounded off the nearest 0.01 increment. The NRC and SAA values normally range from 0.00 to 1.00, with 1.00 indicating 100% sound absorption per square foot of material. These values can exceed 1.00 when thick specimens or specimens with large air spaces are being tested.
