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Fan silencers: everything you need to know

Fans are essential in industrial and commercial environments. But where air is moved, noise is created. This can cause disturbance to employees, residents or building users. A fan silencer is often the solution. In this article, we explain how silencers work, where they are applied and what to look out for when choosing one.

What is a fan silencer?

A silencer is installed in the ductwork of a fan to reduce noise levels. It can be placed on both the inlet and outlet side. The principle: sound waves are absorbed or neutralised, while airflow is maintained as much as possible.

Other ways to reduce noise include acoustic enclosures or vibration dampers, but a duct-mounted silencer is often the most direct and efficient solution.

Why are silencers important?

Reduce noise pollution in production halls, car parks and utility buildings.
Comply with regulations, such as workplace safety and noise limits.
Improve comfort and safety for employees and building users.

Applications of fan silencers

Fan silencers are used in many environments, including:

Industry and production facilities.
Car parks (including smoke and heat exhaust, SHEV).
Utility buildings such as offices, hospitals and schools.
Custom projects where noise reduction is a key requirement.

Types of silencers

Absorptive silencers – absorb noise with acoustic material.
Resonant silencers – effective against specific tones or frequencies.
Special designs – for high temperatures or ATEX environments.

Where can noise reduction be applied in a fan system?

There are several places where noise can be reduced in and around a fan:

In the ductwork – using silencers placed directly in the airflow (inlet or outlet side).
Around the fan – with an acoustic enclosure or sound-absorbing panels, often used in larger industrial installations.
Inside the fan itself – some fans can be designed with sound-absorbing materials or customised impeller geometry to lower noise levels.
At the motor and mounting – vibration isolators or flexible connections limit structure-borne noise transmitted through the building.

In practice, a combination of these methods is often used, depending on the source of the noise and the project requirements.

What to consider when choosing a silencer?

Diameter and air velocity: must match the ductwork and fan capacity.
Noise frequencies: high vs. low frequency noise requires different designs.
Space requirements: length and dimensions are important for integration.
Durability and maintenance: especially relevant for heavy-duty applications.

Silencers in combination with fans

A silencer is almost always applied in combination with a fan. Correct sizing is crucial to avoid unnecessary pressure loss and to maintain fan performance. In custom projects, silencers are tailored to the specific situation.