The reasons behind loud inline fan noise

High noise levels affect us in various negative ways. There are physical and mental responses that can impact our lives. In order to prevent this, you need to keep the sounds at your facilities to an acceptable level. The best way to do it is with one of our silencers. We provide various designs, like inline silencers, so we can silence an array of equipment and systems.

Noise can come from all kinds of sources, including inline fans. However, we don’t always know specifically why irregular levels are occurring. In this post, it is our intention to explain why these fans can become noisier than they should be.

Vortex shedding

The first cause we will go over is vortex shedding. It is a broad band sound that is produced via air separation from the trailing edge and blade surface. You are able to control it to a degree by having a decent blade profile design. Having serrated or notched trailing blade edges, and proper pitch angle will help as well.


Another reason for the noise could be turbulence. It happens in the actual airflow stream and can produce the broad band noise. Sharp bends and edges, as well as outlet and inlet disturbances, shall lead to more turbulent airflows.


Speed is also a massive contributor to fan noise. Let’s say for example that you lower the speed of your fan by 20%. The decibel level is going to fall by 5 dB. It is important to maximise fan efficiency rather than just increasing the speed and rotation.


We need to talk about fan load too. The noise can vary alongside the loads. For example, a higher load can make fans much noisier. However, it varies by model. But, fans are typically quieter when you operate them close to their peak efficiency.

Inline silencers to quieten fans and more

At Ventx, we can design a silencer to reduce the noise coming from all kinds of sources. In addition to fans, we can use them to control generator, compressor, and duct work noises. All of our designs shall differ in terms of appearance and attenuation level. However, they will help you to achieve a safe level.

So, if you need any inline silencers from us, please get in touch. We can design them for almost any need, including retrofitting to very noisy facilities.