Acoustic Treatment
CSI Division 09, Finishes
Materials and assemblies, such as sound-absorbing panels, acoustic ceiling tile, and sound-rated wall assemblies with additional insulation and layers of drywall, specified to control how sound behaves within and between spaces, addressing both unwanted noise transfer between rooms and excessive reverberation within a single room.
Why it matters
Acoustic performance is specified using standardized ratings, such as Sound Transmission Class (STC) for sound blocked between spaces and Noise Reduction Coefficient (NRC) for sound absorbed within a room, and confusing the two, or substituting a similar-looking material with a different rating, can leave a space that looks finished but doesn't actually perform the way it was designed to acoustically.
On a real project
A conference room wall is built as a sound-rated assembly with staggered studs, additional insulation, and double layers of drywall to achieve a specific STC rating, rather than a standard partition wall that would let conversations carry through to the adjacent space.
Who this matters most to
A Carpenter builds sound-rated wall assemblies to the specific detail the acoustic design calls for, since a shortcut in the assembly, such as a missed insulation layer or an unsealed penetration, can measurably reduce the wall's actual sound isolation. An Architect specifies the acoustic rating requirements based on the space's actual use, and coordinates the wall and ceiling assemblies needed to achieve them.
Where this goes wrong
A contractor builds a sound-rated wall between two conference rooms but leaves a gap where electrical outlet boxes on opposite sides of the wall are mounted back-to-back in the same stud cavity, rather than staggering them. Sound leaks directly through that shared cavity, and conversations carry between the rooms despite the wall otherwise meeting its acoustic rating everywhere else.
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