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

HVAC Silencer Installation Details

The duct silencers are the controlling acoustic elements in the HVAC system. Each run must keep the stated straight lengths, hanger spacing, and plenum insulation so the calculated attenuation is actually achieved on site [AC].

Run Count
5 runs
Longest
Run A · 1500 mm
Critical Branch
B2 crossover
Hangers
600 mm max spacing

Run A — VO Live

1500 mm · 40 dB · 1.5 m/s

Longitudinal Cross-Section

1500 mm 50 mm ProRox lining 40 dB attenuation target Velocity: 1.5 m/s

Installation Position

IDU-04 ceiling unit 300 mm straight duct before inlet 150 mm straight duct after outlet [AC] Silencer must be thermally insulated in plenum

Run B — IDU-03 Trunk

1000 mm · 25 dB · 2.0 m/s

Longitudinal Cross-Section

1000 mm 25 dB attenuation target Feeds B1 and B2 branches Velocity: 2.0 m/s

Installation Position

IDU-03 shared unit 300 mm straight before inlet Branches split to B1 and B2 after trunk section

Run B1 — Control Room Branch

500 mm · 15 dB · 2.0 m/s

Longitudinal Cross-Section

500 mm 15 dB attenuation Control branch silencer

Installation Position

300 mm straight before inlet 150 mm straight after outlet Branch from Run B trunk toward Control Room diffuser line

Run B2 — Editing Branch

300 mm · 10 dB · 2.5 m/s max

Longitudinal Cross-Section

300 mm 10 dB attenuation target Velocity: 2.5 m/s max Critical crossover branch

Installation Position

300 mm straight before inlet 150 mm straight after outlet Run B2 must stay isolated from Control branch to stop crosstalk

Run C — Video Studio

1000 mm · 25 dB · 2.0 m/s

Longitudinal Cross-Section

1000 mm 25 dB attenuation target Velocity: 2.0 m/s Studio branch

Installation Position

IDU-05 ceiling unit 300 mm straight before inlet 150 mm straight after outlet [AC] Thermally insulate silencer casing in plenum

IDU-03 Crossover Warning

[HP] Confirm branch separation before close-up

IDU-03 serves Control Room AND Editing Suite. B1 (Control) and B2 (Editing) branch from a single trunk. A 15–20 dB silencer is required on the B2 crossover branch to prevent acoustic crosstalk between rooms [HP].