I have a extractor fan that blows air into rigid ducting, first into a 90 degree bend and then a straight length of tubing about 3 meters long. I don’t think there is anything holding the ducting I’m able to move one end of it, the other end sticks out through a brick wall. As air blows through it it’s vibrating and causing noise.What can be done to quiet it down, I don’t thing it’s possible to mount it properly without major work. Would pulling it out and replacing it with something else be better?

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Reelplayer t1_j5au5fu wrote on January 21, 2023 at 5:32 PM

Can you get the noise to stop by using something (like your hand) to stabilize the duct? How have you confirmed the noise is from air passing through the duct and not the fan itself?

As a side note, exhaust fans are notoriously noisy. They are often undersized with a high speed fan. The quietest ones use a larger duct and slower, bigger fan. Insulated, flexible duct can also help.

PerspectivePure2169 t1_j5c72of wrote on January 21, 2023 at 11:05 PM

This is the answer. Something is loose, OP needs to find that and tighten or secure

Adamdaly OP t1_j5ax87o wrote on January 21, 2023 at 5:52 PM

I can’t access the duct while the fans in place, but with the fan unscrewed it’s pretty quiet, I can somewhat trigger the noise while holding the fan in place.

rannison t1_j5au3gu wrote on January 21, 2023 at 5:32 PM

Thick felt, thick nanotape, silicone-based lubricants, Big Stretch or other acoustically insulative sealants, mass loaded vinyl, etc.

Adamdaly OP t1_j5axc6l wrote on January 21, 2023 at 5:53 PM

I don’t know what any of these are but I’ll have a look, thanks.

rocketPhotos t1_j5bvzsb wrote on January 21, 2023 at 9:50 PM

Duct tape is always an option to damp metal vibrations