STC Ratings. Wall assemblies are rated by sound-transmission class (STC). The STC rating is the approximate reduction in noise level through the wall. So, for example, a 50 dB noise would sound like a 15 dB noise on the other side of an STC 35 wall system. A typical 2×4 wall has an STC rating of about 35. FIBER GLASS & MINERAL WOOL ENGINEERED TO OUTPERFORMTM VS. FIBER GLASS & MINERAL WOOL VS. CELLULOSE INSULATION: COMPARING THE FACTS ... Fiberglass and rock wool absorb less than 1 percent of their weight, whereas cellulose absorbs 5-20 percent of its weight. Richard T. Bynam, Jr., Insulation Handbook (New York McGraw-Hill, 2001), p.78.
Aug 29, 2016 · SOUND TRANSMISSION CLASS (STC) – An integer rating of how well a building partition such as an interior wall, floor/ceiling, door, window, or exterior wall attenuates airborne sounds ranging between 125 and 4,000 Hz. The STC value approximates the decibel reduction provided by that particular partition. Background: