STC 1

Question 0

The STC rating figure very roughly reflects:

Answer 0

the decibel reduction in noise that a partition can provide.

Question 1

Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates:

Answer 1

airborne sound. In the USA, it is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations (see ASTM International Classification E413 and E90).

Question 2

STC roughly indicates:

Answer 2

the decibel reduction in noise a partition can provide,

Question 3

The dB scale (STC) is a logarithmic one and the human ear perceives a 10dB reduction in sound as:

Answer 3

roughly halving the volume - a 40 dB noise subjectively seems half as loud as a 50 dB one.

Question 4

If an 80dB sound on one side of a wall/floor/ceiling is reduced to 50dB on the other side, that partition is said to have an STC of:

Answer 4

30. This number does not apply across the range of frequencies, since the STC value is derived from a curve-fit of many datapoints.

Question 5

Any partition will have less TL at lower frequencies. For example, a wall with an STC of 30 may provide over:

Answer 5

40dB of attenuation at 3000 Hz but only 10dB of attenuation at 125 Hz.