Acoustic Solutions for Impact Noise and Sound Transmission

What Exactly Does IIC, INR and STC Mean?

Sound rating methods have been established by the Federal Housing Administration (now HUD) and the National Bureau of Standards. These sound rating methods are recognized by building construction regulatory bodies and agencies. ASTM and ISO acoustical testing methods are used as the criteria to determine acceptable sound transmission standards.

Impact Insulation Class (IIC)

Impact sound originates when one body strikes another, such as in the case of footsteps, hammering, and objects falling. Impact sound travels through the structure with little loss of energy if the structure is continuous and rigid. Transmission of impact sound can be controlled by isolation. IIC ratings are greatly improved by the introduction of QuietCORK™. The higher the IIC number the better the impact insulation.

Impact Noise Rating (INR)

The earliest single-number rating system was called the Impact Noise Rating (INR). This has since been replaced by Impact Insulation Class (IIC) as described above. IIC values will usually be around 50 points above the corresponding former INR values. This explanation of INR is given here simply to assist those still working with the old INR methods.

Sound Transmission Class (STC)

Sound Transmission Class (STC) numbers have been adopted by acoustical engineers as a measure of resistance of a building element such as a floor or wall to the passage of audible sounds. Audible sounds are defined as voice, music, or any other noises not related to impact sound. STC ratings are greatly improved by the use of QuietCORK™. The higher the STC number the better sound barrier.

QuietCORK™ materials have been tested for their acoustical properties. See Testing Results. Certified copies of all testing results may be obtained by request from Jelinek Cork Group.

Due to variables, Jelinek Cork cannot warrant the accuracy of the values. The final material choice and determination of values is that of the buyer and Jelinek Cork cannot be held responsible.

QuietCORK™ by Jelinek Cork Group
Acoustic Solutions For Impact Noise and Sound Transmission