Acoustic Flexible Ducting versus Aluminium Un-Insulated Flexible Ducting

While your HVAC or extraction system may provide many comforts, it has one major downside. Such systems can be a bit noisy at times. Systems that operate with larger fans especially could produce a lot of noise. Today we are going to talk a bit more about acoustic ducting. More precisely, acoustic flexible ducting and comparing it with its smaller brother, aluminium un-insulated flexible ducting. We are also going to mention some ways through which you can add duct sound insulation when using rigid ducting.

Flexible ducting. What it is and where it is used?

Flexible ducting is a ducting pipe that could be shaped however is needed in order to pass around and over various obstacles. It is commonly used in domestic HVAC systems and extractor fans. Mostly preferred for short duct lines because it is quite easy to puncture a hole through them. The flexibility of this type of ducting material is what makes it a go-to product for short ducting lines in tight spaces. Chances are that you have a piece of flexible ducting installed in your home without even having an HVAC system. It would be connecting your kitchen extractor fans to the outlet that lead outside of your home. It is used to extract the smell and humidity of whatever you are cooking.

Sometimes flexible ducting is also used in attic installations, where the pipes have to constantly travel over and under construction pillars.

Acoustic flexible ducting – applications and tips

Acoustic flexible ducting is made from the same material as it’s flexible ducting counterparts – aluminium, fibreglass and some spiral steel wire. What gives this product it’s acoustic properties is that you actually have two layers of flexible ducting separated by a layer of insulating fibreglass in-between. The internal foil layer of the duct is also perforated along its entire length with micro perforations to enhance the acoustic performance. So, how does acoustic flexible ducting work?

The noise from your fan and the air flowing through the pipes make the flexible ducting vibrate, hence there is some noise being accumulated. When you use acoustic flexible ducting, the vibration and noise now travel from the first layer of flexible ducting through the fibreglass. The fibreglass itself cancels a lot of the generated noise and vibration and transfers them to the second layer. This brings noise levels down and limits noise pollution, which could be a major problem in some applications.

Here are a couple of additional tips to further bring down noise levels:

• When you are installing flexible ducting, don’t go for sharp angles. Make sure you leave gradual curves. This will make air travel easier through the bends, resulting in less noise and vibration.
• Make sure to stretch the acoustic ducting as much as possible. This leaves less material to vibrate and shift around when pressured air is passing through.
• You can mount your fan on bungee cords if possible. This will result in less vibration from the fan’s movement being transferred on the ducting.

Note: Acoustic flexible ducting will not completely remove the generated noise.

Additional solutions for duct sound insulation

But what if you have solid steel ducting pipes and you need to bring the noise level down. Do you need to re-do the piping with acoustic ducting? Of course not. In such cases, you can wrap the steel ducting in foil-faced duct wrap. Another method is to spray foam over the ducting pipes, which creates additional layering and also provides thermal and acoustic insulation.

Wondering how to reduce the noise levels from your specific commercial or domestic system? Give the professionals in our office a quick call at 01455 616444. Explain to them what you are dealing with and they can give you their expertise, plus source you with all the materials you need. Flexible acoustic ducting, J-clips, fans, everything you need to build a system from the ground up.