Products to Improve HVAC Noise Control in Commercial Buildings

There are a lot of reasons why people don’t really want to hear noisy HVAC systems. Teachers can’t talk over the whispers of students and rattling ductwork. Hospitals don’t have the benefit of soft materials like carpeting to absorb sound and are acoustically live. Sound reverberates longer in acoustically live spaces, so it’s important that HVAC systems and their components don’t add to the general medical hubbub. That’s where silencers come in.  

There are a variety of characteristics that should be considered when selecting silencers, so design engineers should consider these anytime a silencer is used in HVAC systems: 

• Insertion Loss: This is the difference in the sound power level of a system with and without a silencer. This number should be the same as or higher than the required performance.  
  
• Pressure Drop: All actions have consequences! Creating an obstruction in the airstream will cause a pressure drop, but it should be the same or lower than the allowable pressure drop. 
  
• Generated Noise: When air flows through a silencer air passage, some noise is generated. Those noise numbers are negligible but should be considered especially when the noise rating needs to be NC 20 or lower, like recording studios or performance halls.  

Noise control products are widely available from Price Industries to keep every application running smoothly…and quietly. 

Absorptive (Dissipative) Silencers 
Absorptive silencers can easily be incorporated into HVAC systems to provide in-duct noise attenuation. There are multiple sizes and shapes available for straight ducts, elbows, circular ducts, and fans. Absorptive silencers absorb sound energy rather than reflect it. These silencers are often used in office and retail applications. 

Film-Lined Silencers  
Film-Lined Silencers use (you guessed it!) a thin polymer film liner to separate acoustic media from the airstream. These are often used in classroom and healthcare applications.

Packless (No Media) Silencers 
Often used in laboratory and healthcare applications, these silencers attenuate noise using resonant chambers located behind a perforated metal liner with no fill. 

Air Transfer Silencers 
These silencers provide seamless attenuation solutions for common return plenums addressing radiated and flanking noise. These engineered solutions are a superior alternative to field-fabricated lined boots. They include the return air canopy, return air silencers, and cross-talk silencers. 

Acoustical Louvers 
These louvers are available in a variety of materials and finishes with multiple mounting and screen options. The louver depth ranges from 6” to 24” and allows for air transfer in space restrictive installations. 

Acoustic Panels and Enclosures 
There are custom-engineered solutions available ideal for enclosure and barrier applications for unwanted noise and thermal concerns. Fully insulated tongue-and-groove joints are standard. Options include access doors, structural analysis, and various liners. 

Acoustical Analysis Software 
Price offers acoustical analysis software for new building design, which reduces the risk of error when considering acoustics and virtually guarantees accurate performance predictions. To use the analysis tool, you need performance data for specific HVAC components like air handling units. After you have that data uploaded, you plot the sound path, including all the elements involved from beginning to end like elbows, straight ducts, junctions, and more. Price has conveniently uploaded a variety of standard preprogrammed receiving spaces along with their ASHRAE noise criteria requirements. After all the data is input, the acoustical analysis tool will display the expected sound output. If Price duct silencers, air transfer silencers, or acoustic panel elements to the project until you meet the requirements desired. You can then export an order list and customized product submittals for your Price Noise Control products.  

There are noise control options available for every application. Connect with your Hoffman & Hoffman sales representative to discuss the best options for your next project.