Acoustic silencers are duct-system components that absorb sound-wave energy while allowing airflow. Used in HVAC ducts, generator air inlets/outlets, fan lines and exhaust lines. Splitter (absorptive) and reactive (resonant) are the two main types; correct design adds 25-40 dB attenuation.
What is an acoustic silencer?
An acoustic silencer is a special duct piece that contains parallel-arranged absorbent-filled panels (splitters) or an acoustic-labyrinth structure inside. It permits airflow while absorbing sound-wave energy. A standard ventilation duct is acoustically an open passage; without a silencer, the wall insulation's performance halves.
Silencer types
1. Splitter (absorptive) silencer
Parallel absorbent-filled plates spaced 100-200 mm apart. Broadband performance, moderate pressure drop. Standard for HVAC and generator air inlet.
2. Reactive (resonant) silencer
Expanding/contracting volume chambers + Helmholtz resonator. High-temperature resistant (critical for exhaust), narrow-band performance.
3. Combined silencer
Splitter + reactive in one; broadband + narrow-band combined. For premium applications.
Silencer selection criteria
- Airflow rate (m³/hour): for pressure-drop calculation
- Frequency band: by source type (generator 250-2000 Hz, fan 500-4000 Hz)
- Duct cross-section: air velocity limit 8-10 m/s
- Fire class: A1 / A2 fill mandatory
- Temperature: 400°C+ resistance for exhaust
Typical use areas
- Generator air inlet and outlet (1.5-3 m length)
- HVAC main duct (AHU outlet)
- Industrial exhaust
- Cooling tower ventilation
- Fan blower outlet
- Mechanical room air inlet/outlet
- Facade louvre and wall plenum
The importance of correct design
An undersized silencer raises air pressure, dropping fan performance. In our practice, every silencer is designed with a pressure-drop calculation, air-velocity check and frequency chart.
Target performance
- Airborne reduction: 25-40 dB
- Pressure drop: < 50 Pa (additional)
- Air velocity: < 10 m/s
- Fire-class compliance
Certificates
Products are EN ISO 7235 silencer test, EN 13501-1 fire class and ISO 14163 sound-absorption test certified.
Features
On-site acoustic measurement and noise source analysis
Detailed engineering with professional simulation software
Certified material selection (BS476 Class 0, UNI 9175)
Meticulous installation and execution with our experienced team
Final measurement and performance warranty report
Process
Survey & Measurement
On-site survey and acoustic measurement.
Simulation & Design
Simulation with acoustic software, detailed quote.
Installation
Turnkey installation with certified materials.
Verification & Report
Final measurement, performance report, warranty.
Technical Specifications
| Application Standard | BS476 Class 0, UNI 9175 M1, Firex |
|---|---|
| Typical Noise Reduction | 25-45 dB (project-dependent) |
| Installation Time | Confirmed after survey (1-15 days) |
| Warranty | Measured result + 2-year workmanship warranty |