First up if the original architectural drawings are accessible it may be possible to look up the design assembly and postulate the intended stc rating by comparing that data to existing lab test data.
Stc ratings for concrete floor assemblies.
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.
Determining sound transmission class stc for concrete masonry.
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.
The standard requires a minimum laboratory stc rating of 50 for party walls and floor ceilings.
In order to properly ascertain the stc rating of a wall or other assembly there are two approaches lab comparisons.
Stc is calculated by taking the transmission loss tl values tested at 16 standard frequencies over the range of 125 hz to 4000 hz and plotted on a graph.
To view different wall assemblies click on each point below that may apply to your project.
While this is a good.
The estimated ratings are based on laboratory test results from various compendiums of stc ratings.
It is recommended to consult a professional acoustician for more detailed information or to analyze the specifics of your project assembly.