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How metal makes noise

Conventional air ducts are still the most common go-to solution for air distribution on many occasions. If we are talking about loud facilities, extra noise coming out of the duct does not make a huge difference, but in quiet spaces, even a slight pop or a whistle will not go unnoticed, and it irritates occupants. As most of these traditional ducts are made of metal, some of the key reasons for how the noise starts in the ducts should be addressed.

Most of the time, the noise will be caused by excessive airflow, resulting in a whistling sound. As metal can carry noise throughout all the ductwork, it is possible to hear this whistle in every spot of the facility. The other common issue is the noise coming from the fan. The fan noise is easily transmitted through the structure of the metal ducting. The other most common problem is the temperature difference. When hot air is being rushed into a cold duct, it makes the metal expand, which would result in popping and banging sounds all over the house, office, or any other environment. And then, when the conditions changes and the ducts start to cool, the sounds come back as the metal begins to shrink. There can also be rumbling sounds caused by the oil canning, which happens when the metal starts moving because of environmental conditions and rubs into surrounding surfaces.

Without any doubt, such issues could be slightly altered with additional fiberglass insulation. Or, the ducts can be opened, and acoustic duct liners could be inserted. But why bother with extra effort and costs when you can easily avoid all the issues mentioned above by choosing a fabric-based air distribution solution?

Virtually noiseless fabric-based solutions to the rescue

Unwanted sounds and noise pollution can negatively impact the health and wellbeing of the occupants, as well as on their communication and productivity. This is why minimizing the noise contribution from the ventilation solution is essential. According to National Geographic, the most common health problem associated with noise pollution is Noise-Induced Hearing Loss[1]. Of course, it is highly doubtful that any ductwork would cause such high noises to develop such illness. Still, other health issues, like sleep disturbances and higher stress levels, can result from regular unwanted sounds.

And this is where fabric-based air distribution systems come in handy. The acoustic design of fabric air ducts includes control of sound transmission as well as sound absorption. If properly designed by professional acoustic engineers, fabric ducts can become just as much an acoustic element as well as a provider of a draft-free, virtually silent air dispersion.

Especially in comfort applications, the acoustic properties of fabric ducting are extremely important. Fabric-based solutions absorb sound because fabric ducts reduce sound reverberation by preventing sound from reflecting into the space from the duct surface.  This, eventually, leads to a greater level of occupant comfort.

“FabricAir has the technology and know-how to develop solutions that would perfectly work around the range of 35-40 dB(A), but we can lower it to even 25 dB(A) or lower if needed. Our solutions are perfect for comfort applications as the ventilation system then does not contribute to noise pollution. Even our newest product, FabricAir Ceiling Diffuser for facilities with suspended ceiling, created the noise of only 15 dB(A)”, says Brian Refsgaard, CEO at FabricAir.

Fabric-based ducting can also resolve sound issues that are caused by fans. As mentioned before, fan noise is easily transmitted through the structure of the metal ducting. Contrary, fabric ducting by its nature absorbs this noise because the material is soft. In metal ducting, to absorb this noise, special silencers, sound attenuators, or linen or insulated ducting is used. These are additional expenses and additional resistance to the system, which will cause higher energy consumption. On the other hand, fabric ducting attenuates the fan noise traveling through the metal construction by its soft nature.

Fabric as an acoustic element?

We already covered that fabric-based HVAC solutions can significantly lower the noise in the premises due to their natural properties, but they can also work as an acoustic element. That is the reason why fabric-based air distribution systems are so well received and widely installed in theatres, cinemas, libraries, recording studios, and many more premises that needs this feature.

Such environments require a deficient level of noise so that it would not ruin the overall experience of the occupant, whether he came to watch a play, study or, even record an album. The acoustic design of fabric ducts controls sound transmission and absorption. It also controls sound characteristics within the space.So, working hand-in-hand, acoustic and fabric-based solutions engineers can create an acoustic environment.

Fabric-based HVAC becomes inevitable?

As the construction business is booming, the new building owners and contractors are searching for ways to create the best possible environment for the future occupants of the premises. In this search, HVAC is not being left out. Conventional air distribution systems worked well for many years, but they always had a downside, a fallout that can now be solved with a more affordable, yet just as good or in some ways – better alternative. When it comes to sound properties, fabric-based solutions have the upper hand by solving many issues that come with metal ducts and lessening the health risks associated with sound pollution. In addition, this HVAC alternative creates a draft-free environment with high indoor air quality and maximum comfort for the occupants.