NIC stands for Noise Isolation Class. What does this measurement assess?

• A. Air leakage through a wall.
• B. Heat transfer through materials.
• C. Sound transmitting abilities of a wall construction.
• D. Vibration dampening in floors.

Answer: (C)

Noise Isolation Class measures how well a wall or partition blocks airborne sound from passing between spaces. It focuses on sound transmission through the wall, so higher NIC means better attenuation of noise. It does not assess air leaks (airtightness), heat transfer (thermal performance), or vibration damping (which relates more to impact or structural vibrations). So this rating specifically evaluates the sound transmitting abilities of the wall construction.