Silencing Ventilation Ducts: Methods for Horizontal Fiberboard, PVC Pipes & Plastered Walls

Hello,

Could you tell us how to silence the ventilation ducts in which the air flows from the fans?

Ducts are a kind of horizontal fiberboard eaves, gray pvc pipes, white pvc channels, and the plastered walls in the corner of the room that make up the two walls of the channel (the other two sides are plastic panels.

Someone told me that it is worth lining the canals with felt, someone else - with foam or polystyrene. That's true?

The flowing air whistles on all kinds of "burrs", protruding elements inside the tunnel, narrowings and sharp bends.
The noise intensity increases squarely to the speed of the flowing air.
First of all, make sure that the plow does not get caught on anything, has a good "slip", the felt inside would create additional air flow resistance, while being a perfect habitat for microorganisms.
On the other hand, from the outside, you can additionally cover the tunnel with noise-dampening material, e.g. mineral wool

Link

At the link, there are pictures of insulation, but probably rather thermal.

Thank you for the information in the "barbs" So let go of this felt?

It would also indicate that if you make fiberboard hoods, it is wiser to fold it with the 'smooth side' inward (?).

Still, I am surprised that all the switches for ventilation systems are usually rectangles in cross-section and right angles on bends. After all, even an angled fitting for a regular gray sewer pipe has a pretty nice and smooth transition.

Greetings Marcin.

There are never right angles when cornering, and thermal insulation has two roles, including acoustic insulation.

Always treat gas or air as a liquid and everything will be better visualized for you.

Insert a silencer between the fan and the duct on the discharge side, on the supply side, on the exhaust side, on the suction side, of course.

Link

Thanks for the hint. And what is this noise suppressor?

Google offers various information, but mainly in the fields of automotive (for exhaust pipes) and medicine (earplugs so I guess that's not it.

The noise silencer is a structural element of the AHU or air conditioning / ventilation system. It is designed to filter out the noise coming from the engine and fan. Additionally, the so-called "aprons" between the AHU / fan and the installation for separating vibrations. However, we use shock absorbers between the air handling unit / fan and the building structure.

Noise silencer e.g. such Link

The design depends on the cross-section of the installation, rectangular / round chambers have chambers probably lined with mineral wool or other noise-absorbing material. After the silencer in the air supply direction, the so-called a "steering wheel" that will unify the flow disturbed by the muffler.

Here, "apron" is called a flexible connection, e.g. like this Link it is used to isolate the installation from vibrations of the drive,

and a shock absorber to isolate the building from vibrations of the drive, e.g. Link

Thank you for the information!

Gentlemen, I have also tested a spiro 100 pipe, but when you blow into it, the spiro pipe gives off the same sound as e.g. a sewage pipe, or maybe even louder, so how is the pipe supposed to go through the wall, a short distance of 50/60 cm to the exit.Out of curiosity I installed a fireplace without a pipe of any kind, so only the wind outside can be heard without any reverberation, rumbling etc. but there can't be an empty passage and at the end there is only a fireplace or an air intake, and nothing goes through the middle... but what if instead of a ventilation grille you put such a thing at the end of the pipe in the house?

https://allegro.pl/oferta/anemostat-kratka-na...-z-ramka-i-uszczelka-wygluszajaca-13524440416

Damper for ventilation:
.

>>21353687 .

it's not possible because I have an opening for a 110 pipe and the outer diameter here is over 200. anyone have any other ideas? a throttle of some kind? a non-return flap for example, but then it probably won't open by itself because where would the draught in the house come from to open it?

But you can give this attenuator anywhere in the duct - in the loft, in the false ceiling, or wherever you have them distributed.

Ps now I read your first post again and I don't understand something - what do these "ducts" look like? Aren't they normal steel pipes? Are they definitely ventilation ducts at all, or some kind of sculpture?

My topic mate
https://www.elektroda.pl/rtvforum/topic4092215.html