ACOUSTIC TRANSMISSION COEFFICIENTS ACCORDING TO ASTM E413 STANDARD
is the American Society for Testing and Materials, its technical standards are mainly used in the USA but enjoy international prestige.
is a standard for the classification of the acoustic transmission of materials and, consequently, of their soundproofing properties.
Sound Transmission Class (STC) coefficients
They are single-digit ratings that indicate how an element that divides two rooms is effective in reducing sound transmission of from one side to the other.
- Good soundproofing: most noises do not disturb
- Loud noises are faintly audible
- A loud speech is heard far away
- A loud speech is perceived as a murmur
- A loud speech is audible but not understandable
- A loud speech is understood
- Normal speech is understood