HVAC Silencers for Consistent Acoustic Performance

• Die-formed, single-piece splitter construction minimizes shell-radiated noise for quieter operation.
• Double-skin or splitter designs deliver maximum low-frequency attenuation, tackling the toughest noise challenges.
• Streamlined straight-through air passages and bell-mouth entrances/exits reduce pressure drop and self-noise for efficient airflow.

• Solid, rounded noses and smooth, fastener-free surfaces prevent turbulence and dirt buildup, ensuring consistent performance.
• Perforated metal containment protects acoustic fill from erosion, prolonging the silencer’s lifespan and reliability.

• Quiet-Vent® Silencers solve a common problem in air handling the passage of noise from one space to another through vents provided for air passage. These modern low-cost units are easy to install, permit circulation of air in either direction, yet effectively stop noise in both directions.
• Quiet-Duct® Rectangular Silencers are suitable for conventional applications including low-frequency silencers having acoustic performance specifically engineered for the 63 Hz, 125 Hz and 250 Hz octave bands.
• Clean-Flow Rectangular Silencers are ideal for systems requiring a higher degree of cleanliness and hygiene such as hospitals or clean room applications. Linings on the fill material guard against erosion of particulate matter into the airstream. Specific internal construction features protect the lining against chaffing or premature failure and are necessary to maintain the rated aero-acoustic performance.
• Conic-Flow® Tubular Silencers are available for silencer applications including low-frequency silencers having acoustic performance specifically engineered for the 63 Hz, 125 Hz and 250 Hz octave bands.

• D-Duct Acoustic Diffuser Silencers are appropriate for use on axial fan systems. The combined interior diffuser cone and exterior square jacket casing make these units aerodynamic regain devices as well as silencers.
• Rectangular Packless Silencers are the ultimate solution for ultra-clean environments and corrosive / flammable environments. The complete absence of fill, combined with ease of cleaning and draining makes Packless silencers well suited for engine test cells, chemical plants, refineries and facilities that handle or process hazardous materials.
• Tubular Packless Silencers are excellent for small diameter circular duct systems such as fume hoods. The Packless design of these units makes them equally suitable to the types of systems mentioned for the Rectangular Packless silencers.
• IAC’s Green Duct Attenuator range is the first British made ‘green’ silencer range for air handling applications. With acoustic infill material made from specially developed post-industrial organic fibre, IAC's range of green Duct Attenuators offers a solution to the ever-increasing requirements for eco-friendly HVAC systems.

In 1972, IAC developed silencer Dynamic Insertion Loss and Self-Noise ratings both under FORWARD FLOW (+) and REVERSE FLOW (-) conditions for Rectangular and Cylindrical Duct Attenuators. Since attenuation values are generally higher in the first five octave bands in the Reverse Flow (-) mode compared to the Forward Flow (+) mode, more economical silencer selections can often be made on return air systems. These phenomena are illustrated below.