Wildeboer Software

The correct dimensioning of silencers for ventilation systems: A guide

Find out in this guide how you can use our WiDim dimensioning software to select the right sound attenuators and optimise both the acoustics and energy efficiency of your ventilation system.

Ventilation systems are now an integral part of modern buildings. They provide fresh air and a pleasant indoor climate. However, while they are doing their job, the air flow generates noise that can not only be disturbing but also impair the quality of the indoor climate. A sound attenuator can help here, but selecting and dimensioning the right one requires in-depth expertise and precise calculations. In this blog post, you will learn how to select and dimension the right sound attenuator for your ventilation system.

Why are optimally dimensioned sound attenuators important?

Sound attenuators reduce the noise level generated by the fan, deflections and individual resistances in ventilation systems. They minimise noise pollution for both the surrounding area and people inside a building. However, inadequately dimensioned sound attenuators can lead to insufficient sound reduction, which can have a negative impact on the acoustics of the entire system.
Although oversized sound attenuators reduce noise to a comfortable level, they can also cause high pressure losses and thus high energy costs during operation. Precise dimensioning is therefore crucial for the effectiveness and energy efficiency of your ventilation system.

How do I size a sound attenuator correctly?

Dimensioning a sound attenuator is an important step in ensuring optimum noise reduction in ventilation systems. In this blog post, we show you how to correctly dimension a sound attenuator using WiDim. The following steps will guide you through the entire process:

1. Open WiDim and start the Sound Attenuator module.

To dimension a sound attenuator correctly, first open the WiDim and select the “Sound attenuator” module. This takes you to the user interface, where you can enter all the relevant parameters for dimensioning.

2. Enter the conditions that are relevant to you.

Now you need to determine the specific requirements for your sound attenuator. These include the product type, the baffle type, the baffle thicknesses, the product details, the installation situation, the flow technology, the acoustic requirements and the dimensions. We explain the individual steps in detail.

Product

Select the product you want to dimension. You can choose from:

Baffle

Select the type of baffle that best suits your application or let the program search for both types of baffles:

Broadband baffles: These cover a wide frequency spectrum and are suitable for general sound attenuation.
Absorber baffles: These are specially designed to achieve high attenuation in the higher frequency range.

If both checkboxes are selected, the program searches for the most suitable baffle for your requirements and displays it in the search results.

Baffle thickness

Een groot voordeel van de SKE-geluiddempers en SE-kulissen is de grote keuze aan kulisdiktes – u kunt kiezen uit maximaal acht verschillende diktes. Hierdoor kan het systeem precies worden aangepast aan uw individuele eisen. Door de standaardactivering van de selectievakjes bepaalt het programma automatisch de juiste kulis dikte voor uw toepassing, wat het proces bijzonder comfortabel en efficiënt maakt.

Product details

Click on “Product details” to open further settings:

Specify whether you require a split sound attenuator in height or width.
Select the pressure and leak tightness class that the sound attenuator should achieve.
Adjust the flange profile or an additional perforated sheet cover for the baffles.

Installation situation

The installation situation influences the pressure loss of the sound attenuator. Specify whether the sound attenuator is exposed to free air flow or whether the air flows freely out of the sound attenuator. This selection helps to calculate the pressure loss correctly and to take it into account in the dimensioning.

Flow technology

In this section, you enter the flow specifications:

Volume flow: The volume flow that flows through your system.
Pressure loss: The maximum pressure loss available for the sound attenuator.
The pressure loss can have a significant impact on the energy efficiency of the entire system and should therefore be kept as low as possible.
Maximum flow velocity and maximum inlet velocity: The maximum velocities to be taken into account for the search.

The values for pressure loss and inlet velocity are preset to industry standards, but can be adjusted as required in the programme settings.

Acoustics

Acoustics are a crucial aspect in the design of sound attenuators. WiDim offers you four different design methods. The most common methods include:

Minimum attenuation per frequency: Specify the minimum attenuation you want to achieve at specific frequencies (e.g. 30 dB at 250 Hz).
Maximum residual sound power in total: Here you can specify the input noise (e.g. from the fan) and define the maximum output noise of the sound attenuator. The value for the flow noise (intrinsic noise of the sound attenuator) should generally be 10 dB lower than the residual noise.

Dimensions

Here you can specify the maximum dimensions of your sound attenuator. If you want to specify fixed dimensions, you can do so by clicking on the ‘≤’ symbol. The dimensions searched for are then limited to the dimensions specified here.

3. Find and select sound attenuators

With the WiDim software, you can find the right sound attenuator for your requirements in no time at all. Use the wide range of search options to narrow down your selection and benefit from practical export options for seamless integration into your projects.

Search options

The search options also allow you to narrow down your search to specific requirements. Optimise the search parameters by adjusting the step size or deactivating the optimised search. A smaller search grid and deactivating the optimised search can increase the number of sound attenuators searched, but this will extend the search time. Once you have entered all the relevant parameters, click on “Search” to search for suitable sound attenuators.

Results

The results will now display the matching product variants. These can be further sorted and filtered in the table to find the optimal product.

Adjust result

If no suitable result is displayed, adjust the input parameters accordingly. Values such as dimensions or flow velocity may need to be readjusted.

Export selection

Once you have found the right product, you can easily process it further. WiDim offers you the following options:

Export the data sheet for your documentation.
Save the result in a project so that you can access it again later.
Generate a tender text directly, which makes it easier for you to integrate it into construction projects.
Transfer the data seamlessly into your BIM process using our BIM converter or the numerous interfaces.
Copy the variant key to order the product from us quickly and easily.

WiDim makes dimensioning sound attenuators not only easier, but also more efficient. Despite the wide range of variants, precise filters and automated calculations quickly lead you to a solution that is both technically and economically optimal. This allows you to find the perfect product for your requirements while improving the energy efficiency and acoustics of your ventilation system.

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