KnollTextiles Drapery - Sound Absorbing - Equation
Drapery

Sound Absorbing

ASTM C423 is the industry recognized test for evaluating the sound absorption of a building material. The test report typically lists the Noise Reduction Coefficient (NRC) as a range between “1,” which is said to have 100% absorption (like an open window), and “0,” which is said to be perfectly reflective. If a fabric has an NRC rating of .65, it means that 65% of the sound energy that contacts the fabric is absorbed, rather than reflected.