Sound Transmission Class
Sound Transmission Class (STC) is a single-number rating used to describe how well building elements (walls, doors, windows) reduce sound transmission between adjacent spaces. Standardized by ASTM International and ISO, STC is calculated from sound transmission loss (STL) measurements across the speech frequency range (125 Hz–4 kHz). It is the primary metric used in building codes, product specifications, and acoustic design to ensure privacy, noise control, and occupant comfort.
Source record
Citations copied verbatim from the method’s source record. No claim-level verification is inferred from them.
- ASTM E413-16 (2016). Classification for Rating Sound Insulation. American Society for Testing and Materials. · URL
- ISO 717-1 (1996). Rating of Sound Insulation for Buildings and Building Elements. International Organization for Standardization. · URL
- ASTM E2179-16 (2016). Standard Test Method for Measuring Sound Transmission Loss of Building Partitions by the Reverberation Method. American Society for Testing and Materials. · URL
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