sound transmission class
Isaac Kremer/ November 21, 2025/ / 0 comments
A single-number rating of the performance of a building material or construction assembly in preventing the transmission of airborne sound, derived by comparing the laboratory TL test curve for the material or assembly to a standard frequency curve. Abbr.: STC. The higher the STC rating the greater the sound-isolating value of the material or construction. An open doorway has an STC rating of 10, normal construction has STC ratings from 30 to 60, special construction is required for STC ratings above 60. (Ching, 1995)