NRC or Noise Reduction Coefficient is an acoustical rating that takes the average measurement of a material’s ability to absorb sound. It is measured on a scale from zero—indicating that no sound is absorbed and is considered reflective—to one, which indicates all sound is absorbed and is considered absorptive. Measurements are viewed as a percentage. If a material has an NRC Rating of 0.35, this indicates that it absorbs 35-percent of the sound that hits it while reflecting the other 65-percent back into the space. Soft surface materials like carpet and acoustic panels will have higher NRC ratings compared to hard materials like stone or tile, which have no sound absorbing qualities. The NRC rating can be determined using standardized testing procedures such as the ASTM C423 Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method.