Noise reduction coefficient (NRC)
NRC refers to a surface’s ability to reduce noise by absorbing sound.
A higher score is better. A ceiling with an NRC of 1.00 absorbs all sound. A ceiling with a NRC of 0.00 absorbs no sound. NRC is measured according to the ASTM C423 standard.
NRC is important in areas where people converse in groups and high levels of noise are present, such as classrooms, open plan offices, shops, lobbies and meeting rooms.
Most stone wool products have a NRC of 0.85 or above.