![]() ![]() Unfortunately that test was conducted on a single wall section (4' x 8') rather than the required 8' x 12' wall, thus rendering the test invalid as it does not meet the requirements of ASTM E90. Actual Performance There is one test from an independent lab showing a branded mass loaded vinyl at over STC50 on a 24OC wood stud wall. For significant improvements, one must change this path fundamentally, or introduce specific damping into the structure. The addition of a vinyl layer does little to change this since the outer gypsum will be nailed or screwed directly through the vinyl into the stud. Sound Transmission in Walls In a single stud assembly, the major path of sound transmission is directly through the studs rather than the air in the cavity. Remember individual STC values do not add up. That is, a doubling of mass of the entire structure! When considering any product for soundproofing it is imperative to look for independent lab tests on full scale 8' x 12' walls performed to a current ASTM test method (ASTM E90 and E413). Adding mass to a wall follows mass-law which states that a doubling of wall mass adds about 5 to 6dB of isolation. In fact, an extra layer of gypsum adds only 2-3 STC points to any wall. But you cannot add that 28 to a wall of 30 and get 58. For example, a single sheet of 5/8 inch thick gypsum board by itself has an STC of 28 - 2 points higher than that of one pound vinyl. The acoustic ratings of individual materials cannot be added to existing walls. However presenting bare product performance is not related to the performance in an actual wall. ![]() Vinyl sellers display transmission loss data of bare sheets showing an STC of 26 or more. However a wall already weighs 4 to 5 pounds per square foot before mass loaded vinyl is added, so the extra pound added by a single layer of vinyl is only a small amount of added mass. For this type of acoustical treatment, the mass of the materials is the dominant factor. ![]() Acoustics and Vinyl Noise can be attenuated with additional mass and many companies make vinyl sheets weighing about one pound per square foot. ![]()
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