Stc Ratings For Concrete Walls

Stc ratings for wall floor and window materials and assemblies 3 appendix a stc ratings a 1 walls a 1 exterior a 1 interior a 9 wooden studs a 9 metal studs a 14 floors a 16 wood a 16 concrete a 21 windows a 24 doors a 27 exterior a 27 interior a 29 appendix b references b 1.

Stc ratings for concrete walls. Standard method for determining sound transmission ratings for masonry walls tms 0302 ref. Refer to manufacturer specifications stc what is heard. The green line is the performance of the wall. There are numerous other issues that need to be addressed to get a more accurate.

Because coarse textured units may allow airborne sound to enter the wall they require a surface treatment to seal at least one side of the wall. A wide variety of stc ratings is available with concrete masonry construction depending on wall weight wall construction and finishes. When the mass of a barrier is doubled the isolation quality or stc rating increases by approximately 5 db which is clearly noticeable. Mass is commonly added to existing walls by adding additional layers of gypsum.

If your wall graph is closest to a standard stc 35 curve your wall is said to have an stc rating of 35. Tested systems achieve up to 58 stc have achieved up to 4 hr. All too often this plenums and suspended ceilings unbaffled ducts window to window outdoors common heating units transoms and air grilles unblocked joist spaces uncaulked wall perimeters ducts piping and fixtures masonry joints. The standard requires a minimum laboratory stc rating of 50 for party walls and floor ceilings.

Fire resistance ratings with multi layer designs ul u415 oscillation tested to 1 million cycles to ensure structural performance feature panels with water resistant facings and or mold resistant paper and a water resistant core to help minimize the risk of moisture damage for more information see the following brochures. The magenta line in that graph is the standard reference stc contour. For example a thick concrete wall will block more sound than a thin gypsum 2x4 wall. The stc rating of a cmu wall can be estimated based on its weight using the following formula.

Stc 0 18w 40 where w pounds per square foot psf this information is provided as a tool to help estimate. Stc 14 1w equation 1 is applicable to uncoated fine or medium textured concrete masonry and to coated coarse textured concrete masonry. In the absence of test data standard calculation methods exist which tend to be conservative. The estimate could easily be off by as much as 4 db.

1 contains procedures for determining stc values of. However the additional weight added complexity of construction and poor thermal insulation tend to limit masonry wall partitions as a viable sound isolation solution in many building construction projects.