SOUND TRANSMISSION CLASS (STC)
A system for the measurement of SOUND INSULATION properties of partitions between rooms or buildings, particularly in the case of speech or office noise interference.
Various partitions can be rank ordered on the basis of this measurement, which uses the TRANSMISSION loss of sound in the frequency range 125 to 4000 Hz. However, the measurement is not reliable for low frequency sound or INFRASONIC vibration.
Compare: ABSORPTION COEFFICIENT, IMPACT INSULATION CLASS, NOISE ISOLATION CLASS, SOUND TRANSMISSION COEFFICIENT, SOUND TRANSMISSION LOSS, SPEECH INTERFERENCE LEVEL.