The stc rating of a cmu wall can be estimated based on its weight using the following formula.
Stc ratings concrete wall assemblies.
1 contains procedures for determining stc values of.
Stc is highly dependant on the construction of the partition.
The sound transmission class stc is a single number rating of a material s or an assembly s ability to resist airborne sound transfer at the frequencies 125 4000 hz.
The standard requires a minimum laboratory stc rating of 50 for party walls and floor ceilings.
A wide variety of stc ratings is available with concrete masonry construction depending on wall weight wall construction and finishes.
In general a higher stc rating blocks more noise from transmitting through a partition.
This is usu ally because there is a pronounced dip in the test curve and the stc rating is heavily influenced by a measurement in one fre quency band.
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.
3 5 8 metal studs 5 8 gyp 2 layers total batt insulation.
Stc 0 18w 40 where w pounds per square foot psf this information is provided as a tool to help estimate.