Isolation #1 – A Strategy to Limit Airborne Sound Transmission!

Meeting the sound isolation rating of a ceiling or wall construction is directly affected by materials, workmanship, and flanking sound from penetrations and at joints.  “Composite constructions” (the inclusion of doors and windows with a wall) also compromise the isolation (STC) ratings of walls and are treated section x of this booklet.

Noise isolation between interior spaces: the STC requirements listed assume a continuous wall from the floor of the room to the floor/ceiling system above, sealed at the perimeter (edges, top and bottom). As noted earlier, composite construction that includes a door or window can have a serious negative impact on the STC rating of the wall construction alone if the door or window does not have a similar STC. Composite wall STC rating must be specified based on composite construction calculations.

Noise isolation of open plan classrooms: While flexible learning spaces are possible when very carefully planned, “open plan” classrooms should be discouraged due to disruptive background levels created by adjacent neighboring classes.

Examples of STC and IIC based on layout of adjacent spaces: The following figures show the STC’s for walls and floor/ceiling assemblies based on adjacent spaces as required by ANSI12.60.  A detailed description of STC and IIC requirements is found in Section 4 of this booklet and Clause 5.4 of ANSI 12.60-2010, Part 1.

Core Learning Space minimum STC ratings for walls and floor/ceiling assemblies, seen here in plan view (walls).

An example of ancillary spaces and required STC. Note that the STC also holds for ceiling/floor assemblies between the spaces.

NEW SECTION- Isolation #2: Vibration Isolation Strategies to eliminate the transfer of vibration through the building (and its potential broadcast as audible sound)

[ Can the same section also contain/explain how sound travel through structural systems and how to reduce them? Chin Lin]

[ This comment from Chin Lin is at the end of a long paragraph near the end of his review and it brings up a point that is only briefly covered in Sect. 21– namely, structural transmission of sound. You briefly mention that plumbing lines should be vibration isolated from adjacent structure. Perhaps a stronger statement about this serious short circuit for structural transmission of sound through the pipes into adjacent structure is in order. Consider the old demo of placing a vibrating tuning fork on a table to show how the vibrating tuning fork transmits its vibration into the table which then radiates sound strongly. To be sure, sound is radiated acoustically by the vibrating tuning fork, but it’s the structural transmission of vibration into the table which becomes the dominant sound source. You clearly recognize this problem but it doesn’t seem to be covered in your text as strongly as might be desired – LS]

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