Sound transmission class

Sound transmission class

Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates airborne sound. The STC number is derived from sound attenuation values tested at sixteen standard frequencies from 125 Hz to 4000Hz. These transmission-loss values are then plotted on a sound pressure level graph and the resulting curve is compared to a standard reference contour.

Noise reduction

Noise by definition is an unwanted soundWe, therefore, want to reduce, rather than redirect, noise to acceptable levels, when we talk about controlling itNoise level in a building is a combination of 2 sources: interior noise that produced inside the building and exterior noisePrimary source of interior noise is the use and occupancy of the building Noise can be controlled at its source, in the path between the source and the listener, or at the listenerThe most effective control takes place at the sourceIf noise can be controlled at its source, it is unnecessary to consider the path or listener locationsIf the noise can be controlled in the path, it is unnecessary to consider the listeners location for noise control measures

Control at the SourceControl in the PathControl at the ListenerMaintenanceEnclose sourceRelocate listenerAvoid resonanceInstall barrierEnclose listenerRelocate sourceInstall proper mufflerHave listener use hearing protectionRemove unnecessary sourcesInstall absorptive treatmentAdd masking sound at listener's locationUse quieter modelsIsolate vibrationsRedesign source to be quieterUse active noise controlINTERIOR NOISE CONTROL

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