What is NRC?
NRC stands for Noise Reduction Coefficient. It's a measure used to quantify the effectiveness of a material in absorbing sound. The NRC rating of a material typically ranges from 0 to 1, indicating the fraction of sound energy absorbed by the material across a range of frequencies. A higher NRC value indicates better sound absorption. NRC values are commonly used in acoustics to assess and compare the performance of different products such as acoustic panels, acoustic curtains, and Ceiling Sound Baffle.
The rules for measuring NRC are established by the ASTM C423 standard, which provides specific procedures for determining the Noise Reduction Coefficient. The basic procedure involves placing the test material in a room with known acoustic properties and then measuring the level of sound absorption at various frequencies. This data is then analyzed and used to calculate the NRC, which is the average sound absorption coefficient at 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz. ASTM C423 also provides specific requirements for room size, placement of microphones and sound sources to ensure measurement accuracy.