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Penetration Sealing Details

Electrical, data, and pipe penetration protocols for maintaining acoustic isolation across all STC-rated assemblies.

BUILDER CUSTOMIZATION GUIDE -- PENETRATION SEALING

CUSTOMIZABLE -- Conduit and cable tray brand, junction box manufacturer, cable labelling system and colour coding, face plate style on finished side of wall.

DO NOT ALTER -- Sleeve oversizing dimensions, acoustic sealant type and application method, putty pad specifications around electrical boxes, fire-stop and smoke-seal products, boot and grommet specifications at duct penetrations, number of cables per sleeve, back-fill material and packing sequence. Every penetration is a potential STC weak point -- sealing protocols must be followed exactly as specified.

The Golden Rule of Acoustic Penetrations

Every penetration through an STC-rated assembly must be sealed to the same STC rating as the wall. One unsealed hole destroys the entire wall's acoustic performance. A 1% opening in an STC 55 wall can reduce it to STC 35 or worse.

Electrical Box Penetrations

Detail A Staggered Electrical Box Cross-Section

Staggered Electrical Boxes in STC-Rated Wall
≥ 600 mm min offset 150 mm 2x Gypsum Green Glue Rockwool Putty Pad Putty Pad Acoustic Sealant Room A Room B KEY REQUIREMENTS 1. Putty pad on every box 2. Never back-to-back 3. Sealant at cable entry

Rules Electrical Box Installation Rules

  • No back-to-back boxes on any STC-rated wall. Boxes on opposite sides of a wall must be horizontally offset.
  • Minimum 600 mm horizontal offset between boxes on opposite faces of the same wall.
  • Putty pad on EVERY box — including non-critical walls. This is non-negotiable across all production rooms.
  • Acoustic sealant at cable entry — use Tremco Acoustical Sealant where cables enter boxes. No gaps permitted.
  • Fire-rated caulk where required by local code — especially at plenum barriers and rated assemblies.
  • No standard plastic boxes in STC walls — use heavy-gauge steel boxes with putty pad wraps.

Products Approved Sealant Products

Data/AV Cable Penetrations

Detail B Cable Pass-Through Cross-Section

Sealed Cable Sleeve Through STC-Rated Wall
Rigid Steel Conduit Sleeve Acoustic Sealant Packing Fire Putty Cap Fire Putty Cap Data cable AV cable Editing Room Control Room Sleeve = Wall thickness + 20mm SLEEVE REQUIREMENTS 1. Rigid steel conduit 2. Sealant packing inside 3. Fire putty both ends

Detail C Cable Routing Plan

Approved Cable Routes — All Cables Route Through Editing Room
Buffer VO Live Control Studio Editing Entry D1 Cable Entry J J NO CABLES ALL cables enter via Editing Room (D1 entrance). Cable tray in ceiling plenum. NEVER through buffer air gap.
Power (separated 300mm from signal)
Data (Cat6a shielded)
AV Signal (balanced XLR / HDMI)

Rules Cable Routing Rules

  • No loose cables through acoustic walls — every cable penetrating an STC wall must pass through a rigid steel sleeve sealed on both sides.
  • All penetrations through rigid sleeve + sealant — sleeve packed with Tremco Acoustical Sealant and capped with fire putty.
  • Cable tray in ceiling plenum — route all cables above the ceiling in trays, NOT through buffer wall air gaps.
  • Separate power and signal cables by 300 mm minimum — prevents electromagnetic interference with audio signals.
  • All cables route through Editing room — the Editing room serves as the entry corridor. No direct penetrations between production rooms.
  • Junction boxes at buffer wall transitions — cables transition through sealed junction boxes before entering Control or Studio.

Pipe Sleeve Penetrations

Detail D Pipe Penetration Cross-Section

Acoustically Sealed Pipe Penetration Through STC Wall
25 mm gap Oversize Sleeve Mineral Wool Pack Acoustic Sealant Resilient Wrap Pipe PIPE SLEEVE SPEC Sleeve: 25mm oversize Fill: Mineral wool pack Seal: Both faces

Detail E Refrigerant Line Penetration

HVAC Refrigerant Line Penetration
Buffer Wall Liquid Line 1/2" Gas Line 5/8" Insulation Wrap Insulation Wrap Acoustic Sealant Fill Vibration Isolation Mount Production Room Plenum / Ceiling IDUs are in ceiling plenum above production rooms, NOT inside buffer.

Rules Pipe Penetration Rules

  • Oversize sleeve by 25 mm — the sleeve inner diameter must be at least 25 mm larger than the pipe outer diameter.
  • Mineral wool packing in the annular gap between pipe and sleeve. Compress tightly, full depth.
  • Acoustic sealant on both faces — seal both entry and exit faces of the sleeve with Tremco Acoustical Sealant.
  • Resilient wrap around the pipe at each face of the wall to prevent structure-borne noise transmission via the pipe.
  • Vibration isolation mounts on all refrigerant lines after they exit the wall to decouple compressor vibration.
  • No rigid pipe-to-structure connections within 600 mm of the wall penetration. Use rubber-lined clamps only.

HVAC Duct Penetrations

Detail F Duct Penetration Through Buffer Wall

Main Duct Penetration Through Buffer Wall
Buffer Spine STC 55 300 x 200 mm duct 25mm liner Flexible Connector Acoustic Sealant Duct Liner Oversize Duct Sleeve Supply Side Room Side SILENCER NOTE In-duct silencer installed downstream of penetration Airflow

Reference Silencer Schedule Connection

Silencer Reference

Each duct branch serving a production room includes an inline silencer downstream of the buffer wall penetration. Refer to the HVAC silencer schedule for attenuation values and terminal velocities per run. Silencer lengths and NC targets are defined in the SSOT constants.

Rules HVAC Penetration Rules

  • Flexible connector at every wall transition — duct must NOT have a rigid connection through the buffer wall. Use canvas flex connector on both faces.
  • 25 mm acoustic duct liner inside duct for minimum 1200 mm on each side of the penetration. Liner reduces breakout noise.
  • Oversize sleeve around duct at the wall penetration. Gap filled with mineral wool and sealed with acoustic sealant.
  • Sealant around duct sleeve on both faces of the wall. Continuous bead, no gaps.
  • No rigid duct hangers within 600 mm of the wall. Use resilient isolation hangers to prevent structure-borne noise.
  • Inline silencer installed downstream of every buffer wall penetration, sized per the silencer schedule.
Floor Plan Reference

Approved Penetration Points

Green dots indicate approved penetration locations. Red zones are strictly prohibited. All cable penetrations route through the Editing room.

Penetration Points Map — MediaVerse Studio Complex
VO Live NC-20 Control NC-25 Studio NC-25 Editing NC-35 D1 Entry Power Data E-Box E-Box HVAC HVAC HVAC Ref. Ref. ✕ ✕ Buffer Spine
Approved penetration point
No penetrations (buffer air gap / critical STC wall)
Red zone — hatched area strictly prohibited

Do NOT List

  • Do NOT penetrate the buffer wall air gap with rigid connections — this includes pipes, conduit, duct, or any solid material that bridges the two leaves of the buffer spine.
  • Do NOT install back-to-back electrical boxes on any STC-rated wall — minimum 600 mm horizontal offset is mandatory.
  • Do NOT route cables through the buffer wall cavity — all cables must route through the Editing room and use sealed sleeves at wall transitions.
  • Do NOT use construction foam (expanding polyurethane foam) — it is NOT an acoustic sealant. Use only approved acoustic sealants from the materials schedule.
  • Do NOT leave ANY gap unsealed, no matter how small — sound travels through the smallest openings. Every penetration, junction, and edge must be sealed.
  • Do NOT use standard plastic electrical boxes in STC-rated walls — use heavy-gauge steel boxes with putty pad wraps on all boxes in production rooms.
  • Do NOT make rigid duct connections through the buffer wall — always use flexible canvas connectors at both faces of any wall penetration.
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