Stc Rating For Concrete Walls

When the mass of a barrier is doubled the isolation quality or stc rating increases by approximately 5 db which is clearly noticeable.

Stc rating for concrete walls. The magenta line in that graph is the standard reference stc contour. Simple concrete slabs with density around 2300 kg m 3 and thickness in the range 150 to 200 mm provide stcs from about 53 to 58. For example a thick concrete wall will block more sound than a thin gypsum 2x4 wall. 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.

The table below gives representative stc values and mass per square metre for some concrete slabs. It does not matter whether the slab is a wall or a floor the airborne sound transmission is the same. Stc 0 18w 40 where w pounds per square foot psf this information is provided as a tool to help estimate. The estimate could easily be off by as much as 4 db.

A wide variety of stc ratings is available with concrete masonry construction depending on wall weight wall construction and finishes. If your wall graph is closest to a standard stc 35 curve your wall is said to have an stc rating of 35. The stc rating of a cmu wall can be estimated based on its weight using the following formula. 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.

The standard requires a minimum laboratory stc rating of 50 for party walls and floor ceilings. In the absence of test data standard calculation methods exist which tend to be conservative. Standard method for determining sound transmission ratings for masonry walls tms 0302 ref. 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.

Mass is commonly added to existing walls by adding additional layers of gypsum. Helps ensure that partition sound performance matches the promise of sound tests by sealing off spaces at partition perimeters and around cutouts can increase the stc rating of a double layer steel framed partition from 29 to 53 stc an integral part of high performance usg partition designs for attenuation of low frequency sound from machinery and music suitable for use at the perimeter of fire rated wall assemblies for more information see the following brochure. Stc 14 1w equation 1 is applicable to uncoated fine or medium textured concrete masonry and to coated coarse textured concrete masonry. Adding green glue to boths side of a wall.

The green line is the performance of the wall. There are numerous other issues that need to be addressed to get a more accurate.