By eliminating conventional wood framing, BamCore’s Wall System not only improves the thermal environment of the building but also improves the acoustic environment by lowering sound transmission through the wall. By a combination of material and design, the load-bearing BamCore Wall System substantially attenuates sound as measured by Sound Transmission Class (STC) rating. Sound pollution from the outside environment or from across common walls inside multifamily or commercial buildings has become a major concern to owners and occupants. Typical approaches to attenuate the sound transmission across walls requires expensive and complicated installation and framing techniques. A recent independent test conducted by ISO/IEC accredited laboratory concluded that BamCore’s basic 2”x6” equivalent Wall System with only medium dense cellulose insulation (2.9 lbs./cubic foot), but no special acoustic treatments, achieved a remarkably high STC rating of 52.
For comparison, normal stud walls begin with STC ratings in the 30’s, a difficult-to-build 2”x6” staggered wood stud wall only achieves an STC rating of 50 and an expensive 2”x4” wood stud wall with three layers of Type X gypsum using resilient furring channels and gypsum filler strips only achieves an STC rating of 51. The STC rating is the most common sound attenuation rating used in the design and construction industry to represent everyday interior sound sources. The chart below illustrates the extra work and cost that conventional walls require to make them sound opaque. The front row shows the number of layers of drywall used. The middle row shows when it is difficult to install resilient channels are used. The back row shows the resultant STC rating. As shown, the BamCore Prime Wall System requires no drywall and no resilient channels to achieve a remarkable 52 STC rating.
BamCore’s Wall System also received an Exterior Wall Rating (EWR) of 53. EWR is a more recently developed sound attenuation rating that more accurately reflects exterior sourced sounds. California’s Green Building Standards Code (CALGreen) requires a minimum STC of 40 across common walls separating tenant spaces in multifamily buildings. In locations with known exterior noise sources, exterior wall requirements rise to an STC of 45.