25 |
Normal speech can be understood quite clearly |
Sound Ratings
(IIC)
Impact Insulation Class
Single-number rating that indicates the amount of impact noise isolation provided by a floor/ceiling assembly. The higher the number, the quieter the floor/ceiling assembly.
(STC)
Sound Transmission Class
Single-number rating that indicates the sound transmission loss of a partition or ceiling system between adjacent closed rooms. |
30 |
Loud speech can be understood fairly well |
35 |
Loud speech audible but not intelligible |
42 |
Loud speech audible as a murmur |
45 |
Must strain to hear loud speech |
48 |
Some loud speech barely audible |