Operable Partition Sound Ratings
A movable wall is only as good as what it silences.
The numbers that matter — STC, NIC, and NRC — explained in plain language, with the data behind our guarantee.
STC — the laboratory number
Sound Transmission Class measures how much sound a partition blocks under ideal laboratory conditions. Our ALPHA® all-welded steel panels rate up to STC 54 — strong enough to put a lecture next to a meeting.
NIC — the real-world number
Noise Isolation Class is measured in the finished building, seals and track included — the number occupants actually live with. Our systems field-test at NIC 42 under ASTM E 336, and we guarantee field sound ratings on our large operable walls.
NRC — absorption inside the room
Noise Reduction Coefficient measures how much sound the panel face absorbs rather than reflects. Acoustically absorptive faces to NRC 0.65 are available where echo control matters — worship, music, and assembly spaces.
Mass, welded — not layers, laminated
Sound isolation comes from mass and airtightness. ALPHA® panels put heavy 16 or 14 gauge steel faces on an all-welded perimeter frame — fusion-welded every 8 inches — instead of laminated gypsum skins. The result is a panel that holds its rating for decades and stands up to daily operation.
Specifying for a courtroom, classroom, or sanctuary? Our sound test reports are in the document library, and DWspec® writes the acoustic requirements into your specification in six steps.
Need a number for your spec?
Send us the room and the requirement — we'll match the system and back it with test data.