what does stc stand for
Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates airborne sound.In the USA, it is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations (see ASTM International Classification E413 and E90).ating methodology [edit]. The ASTM test methods have changed every few years. Thus, STC results posted before 1999 may not produce the same results today, and the differences become wider as one goes further back in timeâthe differences in the applicable test methods between the 1970s and today being quite significant.