Traditional ventilation systems generate noise as the air passes through the ducting and into plenum boxes and out through spot diffusers. Fabric-based air dispersion solutions create minimal resistance, thus no significant sound – as low as NC 15.

Noise level considerations differ vastly from application to application. Libraries, theaters, auditoriums, concert halls, recording studios and religious facilities are examples of applications that require very low levels of noise; hence, minimising noise transmissions and controlling sound characteristic within the space are crucial.

Conventional ventilation solutions in metal are rigid and therefore transmit noise. Structural vibrations manifests themselves in the metal, sounds reverberate off the surface, and the airstream generates noise as it travels through the system. The classic ducts may also transport sounds like speech directly from spot diffusers in one room to spot diffusers in adjacent rooms, e.g. in an office structure.

In comfort applications the acoustic properties of fabric ducting are highly relevant. Sound absorption reduces reverberation time, which increases conversation privacy, makes speech more intelligible and can help reduce the general noise level in the space. This leads to a greater level of occupant comfort. The virtually silent nature of the technology means that the fabric duct system doesn't transmit noise.

FabricAir systems typically operate in the 25-30 NC level range, but can be designed to go as low as NC 15. This makes the technology ideal in comfort applications, as the ventilation system then does not contribute negative noise pollution to the space being conditioned. This is why fabric-based air dispersion solutions are the popular choice for theaters, concert halls, schools, and so forth.

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The Lila Cockrell Theater in San Antonio, Texas was upgraded to ensure a healthy work environment for the performers as well as a comfortable experience for the audience. Mike Duarte, from the project team, explains why FabricAir dispersion was the ideal solution for this project. "The stage area presented a specific set of requirements with respect to noise and drafts. We needed to dissipate a lot of heat without causing drafts and movement in the curtains. Using displacement-based air diffusion in the stage area ensured draft-free cooling with NC levels lower than 15. We enabled a high air change with low velocity that created the perfect on stage environment for the performers."

The old metal-based air dispersion system was not circulating enough air to the audience and was an eyesore to the architecture. The team worked with the local architect to create a design that would allow the air conditioning ducts to blend in rather than stand out. "Noise and draft restrictions were also relevant in the seating area, which meant designing a solution that would enable a high air change at low velocity while being quiet and unobtrusive to the space," explains Mike Duarte.

When the newly build facilities of the Danish Broadcasting Company, DR Byen in Copenhagen, Denmark, was facing problems with an inadequate conventional air dispersion solution, they also turned to fabric-based technology. This was a project with very specific requirements in terms of noise (max NC15), air velocity (0,13m/s) and space restrictions, in addition to condensation issues caused by a large ΔT. It was solved using underfloor fabric ducting to deliver the necessary airflow without causing disturbing noise pollution from sound transmission and reverberating. The condensation challenge was solved using a permeable fabric type. It also meant insulation was not needed, making the solution highly space-efficient.

In applications like theaters, auditoriums and concert halls, conventional solutions often fall short, as they require large orifices to generate a high air change. This results in unpleasant, even unhealthy drafts, as well as transmission and reverberation of noise. The same is true for silent applications such as libraries and religious facilities. Fabric-based air dispersion technology is draft-free and virtually silent, thus offers the ideal environment in these application types. They provide a high air change with great levels of comfort.

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