What is STC and IIC Testing?

HGC offers Sound Transmission Class (STC) and Impact Insulation Class (IIC) testing in accordance with ASTM or ISO standards to verify compliance of constructions with design targets or regulatory guidelines where applicable

Sound Transmission Class (STC) Rating Scale

Sound Transmission Class (STC) Testing

Sound Transmission Class (STC) is a laboratory rating commonly used to evaluate a building partition’s ability to resist airborne sound transfer (i.e. talking, children playing/crying). ASTC ratings correspond to the same assembly tested under field conditions. A field test can determine the rating of a partition for compliance with building codes by placing a sound source on one side of the demising wall/ceiling/floor under test, measuring the sound levels in the source room and receiver rooms on both sides of the assembly. Measurements are also taken to determine the ambient sound and reverberation in the receiver room along with the room geometry. The combination of all this data is used to determine the ASTC rating.

Impact Insulation Class (IIC) Testing

Impact Insulation Class (IIC) is a rating commonly used to evaluate a floor/ceiling partitions ability to resist structure-borne impact sound transfer (i.e., walking, shuffling). Standardized field apparent insulation class (AIIC) testing is conducted in the field whereby a standard tapping machine is placed on the floor of the source room, in four different orientations. The resulting sound levels are measured in the room directly below. Measurements are also taken to determine the ambient sound (in the receiver room) and reverberation times along the room geometry. The combination of this data is then used to determine the AIIC rating of the test section.