One of the features of glass is sound proof,whether it’s single glazing, laminated glass,insulated glass or even laminated insulated,the glass can reduce the sounds transferrd from outdoor to indoor.
The order of sound insulation performance from poor to excellent is: monolithic glass < laminated glass

Here we introduce a simple formula to calculate the glass STC-sound transmission class.
1.Monolithic glass
Formula:
R=13.5lgM+13
R:Monolithic glass STC
M:Glass density
Example:6mm clear tempered glass
STC=13.5*lg(6*2.5)+13=28.87dB
2.Laminated glass
Formula:
R+13.5lg(M1+M2)+13+R1
R:laminated glass STC
M1,M2:Glass panel density
R1:Additional STC caused by the glass configuration
For laminated glass,the R1 will be calculated as below:
0.38mm PVB-4dB
0.76mm PVB-5.5dB
1.14mm PVB-6dB
1.52mm PVB-7dB
Example: 21.52mm tempered laminated glass
STC=13.5*lg(10*2.5+10*2.5)+13+7=42.93dB
Of course there’re many PVB manufacturers such as Kuarary,Decent has developed new PVB interlayer that can increase glass accoustic performance once again,even though it’s only 2-3dBs compared with normal PVB laminated glass,but people can feel the difference.
3.Insulated glass/double glazed units
Formula:
R+13.5lg(M1+M2)+13+R1
R:Insulated glass STC
M1,M2:Glass panel density
R1:Addition STC caused by the glass configuration
For insulated glass,the R1 will be 0.1* air thickness
Example: 6+12A+6 insulated glass
STC=13.5*lg(6*2.5+6*2.5)+13+12*0.1=34.14dB
4.Laminated insulated glass
Formula:
R+13.5lg(M1+M2+M3)+13+R1+R2
R1 is addition STC calculated based on PVB and R2 is addition STC caused by the air.
pvb laminated glass : 6+1.14PVB+16A+6
STC=13.5*lg(6*2.5+6*2.5+6*2.5)+13+6+0.1*16=42.91dB
Based on above formula,we can easily find the factors that affect glass accoustic performance:glass thickness,PVB thickness and glass types.
Here we attach a list showing the basic STC performance of normal glass:

Hope our article can help you learn more about glass and apply to your projects.