Sound Attenuation

One of the most common complaints of multifamily living is unwanted sound.

Of course the best time to deal with this is during construction, but most don't think of this until after occupancy.

All Comfort has helped mitigate excessive sound typically in one day, however sound is subjective and behaves similar to water. It is better to eliminate it at the source than to contain it.

All Comfort can typically increase the STC Rating of walls & ceiling assembly by 8 to 10.

Airborne Sound

The STC or sound transmission class is a single number rating used to indicate the effectiveness of an entire construction assembly (partition, wall, floor/ceiling) in resisting passage of airborne sound. The rating is determined from sound transmission loss values (measured in decibels) that are obtained by tests conducted in accordance with ASTM E 90 "Standard Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions." The sound transmission loss values are plotted on a graph and, with the use of a transparent overlay, a single number STC rating is determined. The higher the STC rating the better the sound insulation performance of the construction.

For multi-family dwellings, building codes require minimum STC ratings for partition, wall and floor/ceiling constructions that separate certain building areas and occupancies. These ratings are usually based on multiples of five, such as 45, 50, 55, 60. If a partition has an STC rating between 45 and 50 there is usually little concern whether the test results were 46, 47, 48, or 49, as alt four ratings would meet a minimum rating of 45. However, the partition would not be acceptable for an STC 50 requirement.

The National (BOCA) and Standard (SBCCI) Building Codes, far example, require an STC 45 for partitions and floor/ceilings separating living units from other living units, public spaces and service areas. The Uniform Building Code (ICBO) requires an STC 50 (45 if field tested).

An indication of the approximate effectiveness of constructions with various STC ratings in blocking passage of loud speech is shown in the following chart:

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stc

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