SSOT v3.7 · Contractor Detail Drawing · Acoustic Design Basis

Door & Window Details

All 4 acoustic doors + observation window. Positions from DXF dimension chains, verified against B302. Seal and threshold details are acoustically critical [AC].

Doors
D1–D4
STC Range
45–50
Widths
80 / 90 cm
Window
OW-1 · STC 50

Door Positions

DXF-verified
IDNameSize (cm)STCPositionSwingLocation
D1Entry90 × 22050(434, 0)N into Editingsouth wall, center-right
D2Control90 × 22045(213.6, 19.9)W into Control Roombuffer wall west face
D3VO Live80 × 22045(123.6, 241.1)N into VO LiveVO/Control partition
D4Video Studio90 × 22048(238.6, 189.4)N into Video StudioEditing/Studio partition, west end
OW-1Observation Window80 × 5050(47.7, 241.1)—VO/Control partition

Door Elevations

Per-Door Front Views

Dedicated elevation view for each acoustic door with door-specific dimensions, STC rating, swing direction, seal spec, and hardware. Each door’s spec sheet lists the differences that matter to the contractor (frame depth, seal type, closer type).

D1 — Main Entry Door

D1 elevation — 90cm wide, STC 50, W4 south wall, main entry Front elevation of door D1: 90 cm wide, 220 cm tall, STC 50, magnetic seal, surface closer, main building entry on south wall W4 D1 · STC 50 · 90 × 220 cm STC 50 90 cm 220 cm W4 · South wall · Swing N into Editing
Size90 × 220 cm
STC50 (highest)
WallW4 (south wall, main entry)
SwingNorth into Editing Suite
Frame16 ga, jamb depth 140 mm
SealMagnetic perimeter + automatic drop seal
CloserSurface-mounted + weather deflector

Only exterior-grade door. Magnetic seal required to achieve STC 50 target.

D2 — Control Room Access

D2 elevation — 90cm wide, STC 45, W5 buffer spine, Control Room access Front elevation of door D2: 90 cm wide, 220 cm tall, STC 45, neoprene seal, into Control Room, buffer spine west face W5 D2 · STC 45 · 90 × 220 cm STC 45 90 cm 220 cm W5 · Buffer spine west face · Swing W into Control
Size90 × 220 cm
STC45
WallW5 (buffer spine west face)
SwingWest into Control Room
Frame18 ga, jamb depth 120 mm
SealNeoprene perimeter + automatic drop seal
CloserSurface-mounted, adjustable

D2 is the only entry into Control Room. Buffer spine isolates the room from all others.

D3 — VO Live Booth Access Narrowest

D3 elevation — 80cm wide (narrowest), STC 45, W6 VO/Control partition Front elevation of door D3: 80 cm wide, 220 cm tall, STC 45, neoprene seal, into VO Live booth, narrowest door in project D3 · STC 45 · 80 × 220 cm STC 45 80 cm 220 cm W6 · VO/Control partition · Swing N into VO Live
Size80 × 220 cm
STC45
WallW6 (VO/Control partition)
SwingNorth into VO Live booth
Frame18 ga, jamb depth 120 mm
SealNeoprene perimeter + automatic drop seal
CloserSurface-mounted, adjustable

The only 80 cm door in the project. Narrower leaf reduces structural intrusion into the 5.31 m² VO Live booth.

D4 — Video Studio Access ▲ UPGRADED

D4 elevation — 90cm wide, STC 48 UPGRADED, W7 Studio/Editing partition Front elevation of door D4: 90 cm wide, 220 cm tall, STC 48 upgraded from architect's STC 40 spec, Video Studio access D4 · STC 48 ▲ · 90 × 220 cm STC 48 ▲ 90 cm 220 cm W7 · Studio/Editing partition · Swing N into Studio
Size90 × 220 cm
STC48 ▲ (upgraded from 40)
WallW7 (Studio/Editing partition, upgraded)
SwingNorth into Video Studio
Frame18 ga, jamb depth 120 mm
SealNeoprene perimeter + automatic drop seal
CloserSurface-mounted, adjustable

Contractor warning: Architect drawing shows STC 40. Install STC 48 only. See Frame Specifications section below.

Symbols on all 4 elevations:
  • Purple dashed = magnetic perimeter seal (D1 only). Green dashed = neoprene perimeter seal (D2–D4).
  • Solid green bar at door bottom = automatic drop seal.
  • Three small rectangles on the hinge-opposite edge = 3-point mortise latch positions.
  • Circle + horizontal line at mid-height = lever handle.
  • All doors: solid mineral core, steel-skinned, self-closing. See Leaf Construction and Hardware sections below.

Cross-Section Anatomy

Plan View

Horizontal plan-view cross-section showing leaf build-up, perimeter seals, frame rebate, and automatic drop seal threshold detail.

Acoustic door cross-section anatomy Horizontal cross-section through an acoustic door showing leaf construction, perimeter seals, frame rebate, and threshold detail Acoustic door — horizontal cross-section (plan view) Applies to D1-D4 with varying leaf mass and seal spec per STC target Acoustic wall Acoustic wall Door leaf Leaf build-up (exploded) Steel Damp Mineral core Damp Steel Compression seal (jamb) Frame rebate Threshold detail (section view) FFL Leaf bottom edge Automatic drop seal (retracts when door opens) Threshold plate ~3mm Seal spec varies by STC target: STC 45 = single compression, STC 48-50 = double compression + magnetic assist All doors: solid core, steel-skinned, minimum 44mm leaf thickness, 3-point latch

Door Leaf Construction

85 mm total

Mass-damping-mass sandwich. Asymmetric steel thickness (1.2/0.8mm) prevents coincidence at same frequency.

LayerThicknessPurpose
Steel sheet (outer)1.2 mmStructural rigidity + mass
Butyl rubber1.5 mmConstrained layer damping (CLD)
MDF15 mmMass layer
Rockwool RWA4550 mmAbsorption core
MDF15 mmMass layer
Butyl rubber1.5 mmConstrained layer damping (CLD)
Steel sheet (inner)0.8 mmStructural rigidity (lighter inner face)

Frame Specifications

STC 45–50

STC 50 Frame (D1 Exterior)

Frame16 ga steel, welded corners, filled with sand/lead sheet
Jamb Depth140 mm
Thresholdautomatic drop seal + neoprene gasket
Sealmagnetic perimeter seal, continuous compression gasket
Hardware3x ball-bearing hinges, lever handle, surface closer
NotesD1 exterior — add weather stripping + threshold rain deflector

CONTRACTOR WARNING — D4 (STC 48)

The architect's drawing shows D4 as STC 40. This has been upgraded to STC 48 by the acoustic engineer. The acoustic specification overrides the architect's drawing. Do NOT install an STC 40 door at D4 — the Video Studio / Editing Suite partition (W7) requires STC 48 isolation to prevent crosstalk between rooms during simultaneous sessions.

Reference: SSOT v3.7 — D4=48(UPGRADED), W7=48(UPGRADED)

STC 45 Frame (D2, D3 Interior) — D4 uses STC 48 frame

Frame18 ga steel, welded corners, grout-filled
Jamb Depth120 mm
Thresholdautomatic drop seal
Sealneoprene perimeter gasket, adjustable
Hardware3x ball-bearing hinges, lever handle, surface closer
NotesD2, D3, D4 internal acoustic doors

Hardware & Acoustic Sealing

Critical [AC]

STC ratings are meaningless without proper sealing hardware. Every acoustic door requires all three seal types:

ComponentSpecificationFunction
Automatic drop sealConcealed mortise, silicone bulb, spring-loadedSeals 3-5mm gap between door bottom and threshold when door closes
Perimeter gasketContinuous magnetic or compression seal, 3-sided (head + both jambs)Maintains airtight contact around the full door perimeter
Threshold transitionAdjustable aluminum saddle with neoprene insertBridges float-floor gap, provides drop-seal landing surface
Door closerConcealed overhead, adjustable closing force and latch speedEnsures door fully closes and seals engage — doors left ajar destroy STC

Observation Window OW-1

STC 50

Specifications

Opening80 × 50 cm
STC50
Position(47.7, 241.1)
Sill Height100 cm AFF
Tilt5° (prevents internal reflections)

Glass Panes

Layer 16mm float
Layer 2100mm dry air
Layer 310mm laminated
Layer 475mm dry air
Layer 58mm float

Maintenance Schedule

Annual

Inspection interval: Annual (minimum), or after any physical impact.

Seal Checks

  • Perimeter gaskets: check for compression set, cracking, or gaps — replace if any light visible
  • Drop seals: verify full contact with threshold when door closes — adjust or replace mechanism
  • Threshold gaskets: inspect for wear from foot traffic — D1 exterior threshold especially
  • Magnetic seals (D1): verify magnetic strip alignment and pull force > 2 kg/m

Closer Checks

  • Door closer: verify latching force pulls door fully into seal contact
  • Hinge pins: lubricate annually — squeaking indicates wear that may cause staff to prop doors open
  • Closing speed: 3-5 seconds from 90° to latch — too fast = slam damage, too slow = left open
Warning: Propping acoustic doors open during sessions destroys all isolation. Consider magnetic hold-open devices that release on studio 'LIVE' signal.