Stc ratings are determined by laboratory tests of a.
													
																	Stc concrete block wall. 
									
	
		
	
																	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. 
																	Standard stud wall with one layer of 16mm 5 8 plasterboard. 
																	In general the stl of a concrete masonry wall increases with increasing frequency of the sound. 
																	The higher the rating the greater the degree of noise reduction. 
															
													
									
	
		
	
																	8 concrete block wall painted with 1 2 drywall on independent steel stud walls each side insulation in cavities stc prediction edit there are several commercially available software which predict the stc ratings of partitions using a combination of theoretical models and empirically derived lab data. 
																	8 concrete block hollow core painted 2 coats 2 sides. 
																	Stc ratings for masonry cmu walls is based on weight of the block and whether the cells are filled or not and what material it is filled with. 
																	A stc rating of 55 is required for inter tenancy walls. 
															
													
									
	
		
	
																	A wall floor or roof. 
																	Estimated stc ratings for cmu walls wall thickness in. 
																	Within a dwelling an internal wall with a stc rating of 45 will usually muffle television telephone ringing and conversation in an adjoining room. 
																	8 concrete block hollow core no wall finish. 
															
													
									
	
		
	
																	Many sound transmission loss tests have been per formed on various concrete masonry walls.