Sound Transmission Class definition

Sound Transmission Class. (STC) means a one-number rating of the sound-blocking ability of a partition, door, window, etc., calculated in accordance with ASTM E413 from measurements of one-third-octave band sound pressure levels and sound absorption made in a laboratory and in accordance with ASTM E90.
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Sound Transmission Class or “STC” means (laboratory) sound transmission class as set out in ASTM E90. STC is a single number that is an indication of an assembly’s ability to block sound (i.e. in the speech frequencies). The higher the STC rating, the higher is the sound transmission loss. For instance: loud speech can be understood fairly well through an STC 30 wall but should not be audible through an STC 60 wall;
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Examples of Sound Transmission Class in a sentence

  • All new full height partitions shall be sound insulated, have at least 3” fiberglass insulation and a Sound Transmission Class (STC) rating of 49 minimum.

  • For example, non- amplified discussions (Sound Transmission Class – STC-45 rating) refers to normal voice levels while discussing classified information within the security area.

  • Common walls adjacent to or below fan rooms, toilets, retail areas, and mechanical spaces shall be constructed to ensure the following acoustical performance criteria: Sound Transmission Class (STC) greater than or equal to 55.

  • Acoustical separation is required from the Generation Rooms to the Administration Area with a minimum Sound Transmission Class (STC) rating of 54.

  • All perimeter walls will achieve a Sound Transmission Class (STC) rating of STC 57 Double Stud.

  • The project will require windows with a Sound Transmission Class (STC) rating of 25 or better.

  • In order to achieve the proper sound isolation, all perimeter walls of the Type 4 room must achieve a Sound Transmission Class (STC) rating of STC 55.

  • Sound Transmission Class (STC) An integer rating that measures how well a barrier or building partition attenuates sound.