Older field sound-isolation reports may use the term FSTC, while current ASTM terminology uses ASTC — Apparent Sound Transmission Class.
The terminology change is important when reviewing legacy reports, specifications, and test records, but the underlying purpose remains field evaluation of the installed airborne sound-isolation performance of the separating construction.
Current Field Testing
OSAT performs airborne sound-isolation testing in accordance with the applicable current version of ASTM E336 and reports the field metric required by the project.
See ASTM E336 ASTC Airborne Sound Isolation Testing for the current service description.
