Electrical Box Penetrations
[AC] NO back-to-back boxes on same partition wall — minimum 600mm horizontal offset.
| Requirement | Specification | Reason |
|---|---|---|
| Box material | Steel boxes ONLY — no plastic in STC-rated walls | Plastic boxes flex, breaking seal integrity |
| Putty pad | OSI SpecSeal or equivalent behind EVERY box | Fills void around box, maintains fire + acoustic rating |
| Offset | Minimum 600mm horizontal between boxes on opposite faces | Back-to-back creates direct sound path through wall |
| Camera walls (Option A) | 50mm box extension ring, flush with panel face | Panels can cover outlet zone |
| Non-camera walls (Option B) | 15cm clear zone around outlet, surround with panels | Service access without removing panels |
| Panel attachment near outlets | Z-clip (not adhesive) | Need service access — removable mounting |
Cable Conduit Penetrations
| Element | Specification |
|---|---|
| Conduit type | 25mm EMT steel conduit |
| Wall sleeve | Oversized sleeve, 10mm annular gap around conduit |
| Gap fill | Rockwool RWA45 + Tremco acoustic sealant — BOTH faces |
| Audio separation | Separate conduit from power, 300mm minimum separation |
| Crossings | 90° crossings ONLY where audio and power must cross |
SB-01 / Studio Signal Penetrations
SB-01 — Control ↔ VO Live
Wall
Wall 6 (STC 53)
Conduit
32mm steel conduit
Cable
Mogami W2534 quad-core XLR
Sealing
Rockwool + Tremco both faces
Connection
One end rigid, other end flexible connector
Video/Podcast — SNK-2 Snake Crossing (SN-02/SN-03)
Wall
Buffer spine (W5) — crossed ONLY via the SN-03 penetration kit
Conduit
Under-floor EMT, stub-ups cast with the rafts; oversized steel sleeves OFFSET through BOTH spine leaves (never a straight-through line)
Capture
Sony FX30 + portable field recorder on set + SNK-2 16×4 stagebox → Control patchbay (16ch multicore)
Sealing
RWA45 packing, acoustic sealant BOTH faces of BOTH leaves, putty pads on every box, escutcheons [AC]
S3 BOQ Issue 1
Rooms remain independently bookable; the audio tie is passive (patchbay-terminated)
Rule: Pack annular gap with Rockwool + Tremco sealant. Seal both wall faces. One end rigid connection, other end flexible connector — never rigid both sides. Buffer-spine crossings (SN-01/SN-02/DT-02): only the sleeved, OFFSET SN-03 penetration kits are permitted — a badly sealed snake sleeve voids the STC 55 spine.
HVAC Duct Penetrations
| Element | Specification |
|---|---|
| Duct sleeve | Oversized sleeve, 25mm annular gap |
| Gap fill | Rockwool + acoustic sealant |
| Routing rule | ALL ducts through buffer spine ONLY — no direct wall penetrations between rooms |
| Back-to-back | No back-to-back penetrations on opposite walls of same room |
| Refrigerant pipes | 32mm sleeve, foam backer rod, sealant both faces |
| Flex connectors | 150mm minimum at all IDU connections [AC] |
What NOT to Do
| Mistake | Consequence | Correct Approach |
|---|---|---|
| Back-to-back outlet boxes | STC loss of 10–15 dB through wall | 600mm minimum horizontal offset |
| Plastic electrical boxes in STC walls | Flexing breaks seal, degrades STC | Steel boxes only |
| Unsealed conduit penetrations | Direct sound path through wall | Rockwool + Tremco both faces |
| Rigid connections both sides of penetration | Structure-borne vibration transmission | One rigid, one flexible |
| Foam instead of acoustic sealant | Foam hardens, cracks, loses seal | Tremco non-hardening sealant only |
Approved Products
Sealant
Tremco acoustic sealant
Non-hardening, permanently flexible
Putty Pads
OSI SpecSeal
Fire + acoustic rated
Cavity Fill
Rockwool RWA45
Friction fit, no gaps