Asingle-number rating of the performance of a floor-ceilingconstruction in preventing the transmission of impact noise. Abbr.: IIC. The higher the IIC rating, the more effective is the construction in isolating impact noise. The IIC rating replaces the previously used Impact Noise Rating (INR) and is approximately equal to the INR rating +51 dB for a given construction. (Ching, 1995)
