Selecting a silencer - what to choose for which project?

To reduce the noise generated by ventilation systems, which travels through air ducts as sound waves, it is advisable to add a silencer to the system. When sound waves pass through the sound attenuation material used in the silencer, some of the sound energy is converted into heat through the effect of friction, becoming barely perceptible.

Determining the amount, length, shape, and materials of silencers to be placed in ventilation systems for different types of facilities is a multifaceted challenge for HVAC designers. To ensure an ideal outcome, it is worthwhile to familiarize oneself with the available options for sound attenuation.

Materials

ETS NORD’s silencers are primarily manufactured from galvanized steel sheet. In environments requiring special corrosion resistance, such as swimming pools, it is advisable to utilize Magnelis, a metallic coating that offers excellent surface protection. It forms a smooth and intact protective layer on the porous hot-dip galvanized steel surface, preventing corrosion. In extreme conditions (e.g., coastal areas and industrial zones), stainless steel sheets can also be used.

According to the requirements of the project, thermal or fire insulation can be installed on the outer surface of the casing if necessary.

In ventilation sound attenuation, mineral wool or polyester is typically used. Instead of soft mineral wool, glass wool boards coated with ISOVER’s Cleantec fabric can also be used. This effectively prevents fibre material from entering the ventilation system. Each material has its own strengths, which should be examined more closely. ETS NORD experts are happy to assist with material choices.

Circular silencers

Circular silencers are available in various materials and equipped with different damping elements. A wide range of length and diameter options ensures that there is a functional sound attenuation solution for every application.

Circular silencers also include rectangular models with rounded channel outlets at their ends. Especially in small ventilation units, corner silencers are used, which integrate vertical or horizontal direction changes. This allows for compact overall dimensions, fitting the device into even tight spaces.

The range of silencers also includes hinged models, which are particularly popular in hygienic hospital environments. The ability to open them allows the damping material to be removed for cleaning, facilitating maintenance and extending the effective lifespan of the unit.

Among the standard-sized circular silencers, there are also models suitable for smoke control ducts and polyester insulation silencers that meet the requirements of cleanliness class M1.

Rectangular silencers

Rectangular lamella silencers can be manufactured according to very individual needs and preferences. The scales for length, height, and depth are extensive, allowing solutions as large as 2.5 x 2.5 x 2.5 meters, suitable for applications such as emergency power generators. All manufacturing and damping materials are available, and mounting rails can also be chosen from various options.

The optimal silencer for every application

A wide range of silencers, not to mention customization options, understandably raises questions. What all should be taken into account during the design phase to successfully select the best solution for the specific purpose?

Having a clear understanding of the whole is important because the ideal outcome is the sum of many factors. Factors such as the need for attenuation, the quality of the sound to be attenuated, the sizes and lengths of ventilation ducts, and other similar considerations alongside the characteristics of the silencer itself all play a role in finding the most suitable solution possible.

Generally, circular silencers perform better but require more space. Corner silencers save space in tight areas. Hinged maintenance hatches help maintain performance and extend the silencer’s lifespan. It’s important to consider duct sizes, and so on.

ETS NORD’s experts are available to assist you in considering these matters. To assist designers, ETS NORD has developed an advanced and user-friendly SILENCERiQ selection program. The accompanying MagiCAD plugin helps ensure accurate sizing in one go.