Stc Rating For Concrete Walls

1 contains procedures for determining stc values of.

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. 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. It does not matter whether the slab is a wall or a floor the airborne sound transmission is the same. The green line is the performance of the wall.

In the absence of test data standard calculation methods exist which tend to be conservative. 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 0 18w 40 where w pounds per square foot psf this information is provided as a tool to help estimate. If your wall graph is closest to a standard stc 35 curve your wall is said to have an stc rating of 35.

Mass is commonly added to existing walls by adding additional layers of gypsum. The standard requires a minimum laboratory stc rating of 50 for party walls and floor ceilings. 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. 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.

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 hollow with insulation 52 53 56 59 corefoam masonry foam insulationis an excellent product for improving thermal and acoustic properties of walls constructed with concrete masonry units cmu. Standard method for determining sound transmission ratings for masonry walls tms 0302 ref. Stc 14 1w equation 1 is applicable to uncoated fine or medium textured concrete masonry and to coated coarse textured concrete masonry.

There are numerous other issues that need to be addressed to get a more accurate. Installing insula tion within a wall or floor ceiling cavity will improve the stc rating by about 4 6 db which is clearly noticeable1. The table below gives representative stc values and mass per square metre for some concrete slabs. Adding green glue to boths side of a wall.

The stc rating of a cmu wall can be estimated based on its weight using the following formula. The magenta line in that graph is the standard reference stc contour.