Acoustic Education

Consider Sound Control

Determining the amount of sound control you will need is one of the most important considerations when you are evaluating operable and other styles of movable partitions for your facility. Give some thought to determining what types of activities will be held in the room(s). A Sunday school classroom requires less sound control than a ballroom.

Sound Transmission Class (STC)

Operable Partitions are classified for their effectiveness in reducing transmitted sound by a "Sound Transmission Class” (STC) rating. This rating is achieved by tests conducted in an accredited acoustical laboratory under the ASTM E90 Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements.

The higher the STC rating, the higher the price of the partitions. Acoustical experts agree that the human ear cannot discern the difference between 1 or 2 STC points. Your operable wall supplier may suggest that you consider an STC rating that is +1 or -1 from a published STC rating. The human ear cannot detect the difference, and you may be able to save money doing so.

However well designed and rated the partition, it won't be able to stop sound from leaking into the adjacent space if the room isn’t designed to control sound. When specifying the STC rating of the partition for your facility, make certain it is equivalent to the rating of the room or you won't achieve the sound control you were expecting. Sound follows the path of least resistance and can leak into adjoining spaces through an open plenum above the partition, through non sound rated ceiling tiles, gaps around light fixtures, through HVAC systems, etc.

Understanding The Acoustics of Operable Walls

For more about acoustics and movable partitions, click on Understanding the Acoustics of Operable Walls. This brochure explains the technical aspects of sound control including Sound Transmission Class, NIC, flanking paths, and more.

Our AIA continuing education program, How to Optimize Acoustical Performance in Rooms with Operable Partitions shows you what to look for in a sound lab report, what to consider when designing a room for use with operable partitions, and more.