Iso-Step is used to prevent impact and structural borne sound from passing through construction assemblies. The IIC (Impact Insulation Class) ratings directly relate to the measure of impact reduction. STC (Sound Transmission Class) ratings are used to quantify how much airborne sound is reduced by a material or construction assembly. Iso-Step is not intended to reduce airborne sound. However, the overall construction assembly, which includes Iso-Step, would have an improved STC value. It is the complete assembly that provides a reduction in airborne sound. The overall assembly would be tested to determine an STC value.
STC (Sound Transmission Class) Quantifies the performance of a material or partition to attenuate airborne sound. This roughly reflects the decibel reduction of a building material or partition. Higher Numbers = Higher Performance.
IIC (Impact Insulation Class): Impact insulation class (IIC) is a number rating of how well a building material or construction assembly attenuates impact sounds, such as footsteps. A larger number means more attenuation.