Impact Insulation Class (IIC)

Definition

Impact Insulation Class (IIC) is a numerical rating that estimates the ability of a floor-ceiling assembly to isolate and reduce impact sounds, such as footsteps or dropped objects.

Purpose

The IIC rating helps in assessing and comparing the soundproofing effectiveness of different floor-ceiling constructions. It is particularly important in multi-family residential buildings, hotels, and other environments where noise control between floors is crucial.

Examples of Use

• Evaluating the sound insulation properties of flooring systems in apartment buildings.
• Specifying materials and construction techniques for soundproofing in new office buildings.
• Comparing the effectiveness of various underlayment products designed to reduce impact noise in residential homes.

Related Terms

• Sound Transmission Class (STC): A rating system that measures the sound insulation of walls, floors, and ceilings for airborne noise.
• Noise Reduction Coefficient (NRC): A measure of a material's ability to absorb sound.
• Acoustic Insulation: Materials or constructions designed to reduce the transmission of sound.

Notes

Higher IIC ratings indicate better impact sound insulation. Various factors, such as floor covering, underlayment, and construction type, influence the IIC rating of a floor-ceiling assembly.