NOISE REDUCTION COEFFICIENTS (NRC)
Designers may often choose materials which have an efficient sound absorbency value and incorporate them within the building design. The level of sound absorbency for a material is stated in NRC (i.e. Noise Reduction Coefficient) values. This value is derived as a result of acoustic testing on the material and determined by calculation from the average amount of sound energy absorbed over a range of frequencies between 250 Hz and 2000 Hz. NRC values are stated for various systems in this bulletin.
NOISE REDUCTION COEFFICIENTS (NRC) = .75 (75%)
(* On Solid Backing, ** On Lath Plaster)