Due to increased mass poured concrete and concrete blocks typically achieve higher stc values in the mid stc 40s to the mid stc 50s than equally thick framed walls.
Stc 50 concrete wall.
Catalog of stc and iic ratings for wall and floor ceiling assemblies russell b.
Stc 0 18w 40 where w pounds per square foot psf this information is provided as a tool to help estimate.
Dupree office of noise control california department of health services berkeley california 94704 introduction building codes.
Sound transmission class stc provides an estimate of the acoustic performance of a wall in certain common airborne sound insulation applications the stc of a wall is determined by comparing sound transmission loss stl values at various frequencies to a standard contour stl is the decrease or attenuation in sound energy in db.
Many sound transmission loss tests have been per formed on various concrete masonry walls.
Staggered or double stud walls are higher rated than single stud walls.
The estimate could easily be off by as much as 4 db.
Usg provides resources here for our ul wall assemblies for seamless integration into any construction project.
Metal stud walls perform better than wood stud walls.
To view different wall assemblies click on each point below that may apply to your project.
These wall assembly files are used for planning and estimation purposes for many ul wall types such as fire rated wall assemblies.
The stc rating of a cmu wall can be estimated based on its weight using the following formula.
This catalog of sound rated wall and the purpose of the indexing system is.
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.
In general the stl of a concrete masonry wall increases with increasing frequency of the sound.
There are numerous other issues that need to be addressed to.
Area separation wall systems area separation wall submittal sheet sa925 wb2129 sheetrock shaft wall systems tested systems achieve up to 58 stc.
Insulation will noticeably improve the stc rating of an assembly.
These tests have indicated a direct relationship between wall weight and the resulting stc heavier concrete masonry walls have higher stc ratings.