HVAC Penetrations
HVAC installation guide covering Daikin VRF cooling, fresh air ventilation, silencer schedule, and wall penetration sealing requirements.
This HVAC layout is the acoustic performance requirement only. Final duct sizing, equipment selection, silencer specifications, airflow rates, pressure drop calculations, and installation drawings must be completed by a qualified MEP/HVAC engineer. The silencer attenuation values in this document are acoustic targets — they are not final engineering specifications.
MEP note: Silencer selection must be verified against octave-band noise data (63–4000 Hz) from actual fan manufacturer curves.
System Overview
System 1: Daikin VRF Cooling
| Type | Variable Refrigerant Flow (Daikin VRF) |
| Indoor units | 3 wall-mounted IDUs |
| IDU-04 | Serves VO Live only — dedicated (north wall, west side) |
| IDU-03 | Serves Control Room only — former Editing branch capped/sealed at trunk (north wall, Control zone) |
| IDU-05 | Serves Video/Podcast only — dedicated (north wall, Video/Podcast side) |
| Outdoor unit (ODU) | 1 unit, south exterior wall |
System 2: Fresh Air Ventilation
| Purpose | Outside air supply with acoustic silencers |
| Distribution | Plenum-based via 76 cm ceiling plenum (audio rooms; Video/Podcast uses a perimeter MEP bulkhead — see note) |
| Silencer runs | 5 runs (A, B, B1, B2, C) — see schedule below |
Silencer Schedule
| Run | Serves | Length | Attenuation | Terminal Velocity | NC Max |
|---|---|---|---|---|---|
| A | VO Live (dedicated) | 1500 mm | 40 dB | 1.5 m/s | NC-12 |
| B | Control trunk | 1000 mm | 25 dB | 2.0 m/s | NC-18 |
| B1 | Control branch | 500 mm | 15 dB | 2.0 m/s | NC-18 |
| B2 | Control (former Editing branch, retained/re-rated) | 300 mm | 10 dB | 2.5 m/s | NC-18 |
| C | Video/Podcast (dedicated) | 1000 mm | 25 dB | 2.0 m/s | NC-18 |
The former Editing branch off IDU-03 is capped and sealed at the trunk. No crossover duct remains, so there is no IDU-03 room-to-room flanking path.
Silencer: Run B2 is retained and re-rated to serve Control only (NC-18).
Risk level: LOW (single-room service, no crossover).
NC-12 achievable — dedicated IDU-04 eliminates shared chassis flanking from Control Room. No crossover duct to VO Live.
Confirm: IDU-04 self-noise at minimum fan setting ≤ NC-12 curve with supplier.
Wall Penetration Rules
- Every duct penetration: oversized sleeve with 25 mm annular gap, packed with Rockwool + sealed with acoustic sealant on both faces
- No back-to-back penetrations on opposite walls — offset by minimum 600 mm to prevent direct sound path
- Daikin VRF refrigerant pipes: 32 mm sleeve, foam backer rod, acoustic sealant both faces
- Buffer spine = ONLY permitted duct routing path between east/west zones — no ducts through perimeter walls between adjacent rooms
- Plenum barrier walls: full-height gypsum from ceiling tile to structural slab at every partition — sealed with acoustic caulk on both faces
Penetration Sealing Detail
| Layer | Product | Specification |
|---|---|---|
| 1. Sleeve | Galvanized steel | 25 mm larger than duct on all sides, fixed to wall structure |
| 2. Packing | Rockwool | Fill annular gap, compressed to 80% density |
| 3. Sealant | Acoustic sealant (Tremco or equiv.) | Full perimeter, 25 mm depth minimum, both faces |
| 4. MLV boot | 1 lb/ft² mass-loaded vinyl | Wrap around duct ±150 mm from wall face |
| 5. Fire collar | Intumescent collar | Both sides of wall — required for fire compartmentation |
Daikin VRF Refrigerant Pipe Sealing
| Layer | Product | Specification |
|---|---|---|
| 1. Sleeve | PVC or steel | 32 mm diameter, centered on pipe |
| 2. Backer rod | Closed-cell foam backer rod | Fill annular gap, compress to contact |
| 3. Sealant | Acoustic sealant | Both faces, full perimeter |
Plenum Barriers
| Barrier Location | Material | Purpose |
|---|---|---|
| Above buffer spine | 15 mm Knauf Soundshield Plus, sealed to slab | Prevents flanking between east and west zones |
| Above VO/Control partition | 15 mm Knauf Soundshield Plus, sealed to slab | Prevents flanking between VO Live and Control Room (plenum path) |
| MLV curtains at duct crossings | 1 lb/ft² MLV, ceiling to slab | Acoustic curtain wraps around ducts where they cross plenum barriers |
The Video/Podcast room keeps a HIGH 340 cm clear ceiling over the open floor. The hanging MEP services (IDU-05 refrigerant/condensate and the fresh-air/black duct) are boxed into a deep perimeter bulkhead rather than a full dropped plenum, preserving the 340 cm clear height in shot. This bulkhead is also built as a real bass device (≥300 mm mineral-wool fill + sealed cavity, α₁₂₅≈0.55 — the deep perimeter bass soffit).
Access: provide an HVAC service hatch in the perimeter bulkhead for silencer Run C, dampers, and refrigerant joints — sealed acoustically when closed.