Centrifugal fan silencers decrease fan operating sound pressure levels. You can use a fan silencer (also known as a duct silencer) on the fan inlet, outlet, or both, and position them either vertically or horizontally.
When You Need a Fan Silencer
Centrifugal fans can often cause or contribute to excessive industrial noise levels, especially if there is an open inlet or outlet. A fan silencer can go a long way to reduce the noise levels for these applications. We should note that duct silencers often require additional accessories, such as weatherhoods, bird screens, and/or filter boxes.
Selecting your Fan Silencer
At the discharge of the fan, you’ll need to consider velocity, pressure and temperature control, as well as material handling requirements and corrosion resistance.
Additional factors include:
- The kind of fan you’re using,
- The configuration of your ductwork
- The allowable drop in pressure
- How much industrial fan noise reduction you need
Once you assess all of these factors, you will be ready to select the optimal fan silencer for noise reduction.
A Word about Calculating Noise Levels
There are three units of measure related to industrial fan noise levels:
- Fan Sound Pressure (Lp)
- Fan Sound Power (Lw)
- Decibels (intensity of sound (dB))
The Air Movement and Control Association (AMCA) provides testing standards for fan Lw levels, which are derived through calculations best done by your application engineer and/or an acoustical engineer.
According to a June 2017 article in Processing Magazine, typical industrial noise levels from a fan application can range from about 70-120 dB. You will also find an in-depth discussion of fan sound measurement and calculation in the article, titled Understanding Fan Acoustics.
We can give you a strong start by providing the expected sound power and pressure levels the fan will deliver based on its surrounding conditions. Then, based on your application, we will often recommend a fan silencer to handle any application-specific industrial fan noise reduction requirements.
Contact us to get started.
Other Helpful Resources
Senior Application Engineer Chet White provides a demo in this 20-second video and you can learn more about fan silencers and sound levels in our blog, Sound Advice: Do You Need a Fan Silencer.