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Airing on the Side of Caution: Ventilation

 

One of the early discoveries customers make about our tension fabric structures is how air tight they can be. We have gone to considerable effort to make sure the weather stays on the outside of our buildings, and we’ve been very successful. However, when your buildings are as tight as ours, it’s very important to have good ventilation. You want to keep the weather out but the air moving.

We work with our customers on all aspects of their buildings, but it’s important to remember that there is no substitute for bringing in HVAC professionals and specialists as part of your project. We design buildings however independent HVAC experts may be required on the project.

That said, there are some unique aspects of our tension fabric structures you should consider as you think about ventilation.

Open buildings

Many of our structures are open-air storage buildings or equestrian arenas that have roofs but no walls. Logic would dictate that you don’t need ventilation for such open-air structures. Maybe, but maybe not. Troy Jurek, Legacy’s Operations Manager, explained that air in still environments, where there isn’t much wind, will only move about 200 feet on its own. Some of our buildings are much larger than that, often with high ceilings, so he recommends roof vents to get rid of potential pockets of stale air. He says it’s better to err on the side of fresh air.

Passive Ventilation

This is one of Legacy’s most popular options, and it works by fostering natural ventilation. Legacy is unique in its building designs because, unlike most other fabric buildings, ours have eaves. With eaves, you get soffits. With our soffits, you can add vents that draw air into the building. The combination of roof vents and soffits create natural air flow as warm air rises, flows out the roof vents and thereby draws more air in through the soffits.

Passive ventilation means you may not need mechanical ventilation, and that saves you money up front and over the lifespan of your structure. It also means that you can put a building in a remote area where there isn’t access to electricity*.

“We are really happy with the natural ventilation,” said James Kesler, head of cargo and development for Ontario International Airport in California. “We had a system designed for forced ventilation, which would have been very expensive, not only to put in but to operate. We went with the system you designed. I was in the buildings on a pretty hot day. They are cooler now than the buildings the clients are currently in, so they are very happy, too, with the passive ventilation system.”  The passive ventilation is also very helpful to assist with mitigating condensation build up within the building.

Mechanical Ventilation

Our lined, insulated buildings are even more air tight because you now have two impermeable fabric barriers instead of one. That’s usually when the HVAC experts need to be called in. Those conversations between Legacy and the HVAC company are usually very straightforward, just a matter of explaining how to connect their equipment through the fabric exterior. We make a point to explain to the pros that our buildings don’t leak the way they may be used to with other structures. “A fabric building is not generally what they work on every day, so we work to assist them in understanding the intricacies of a fabric building.” said Jurek.

Ventilation becomes part of the design conversation at different times depending on the building, says Jurek. In some cases, like a salt shed, it comes later in the design. In an aquatic center, however, it’s a consideration at the beginning of the design process. Sometimes a customer will know, right up front, about ventilation requirements. Then it’s easy. Jurek says some clients will come in and know they need 2-4 air exchanges per hour. In those cases, it’s a simple matter of math.

 

*Our tension fabric structures have Exxotec™ roof panels that allow up to 12% natural light through. Building owners often discover they may not need electric lighting because they have enough from the sun.


 

SaraDavis

 

Sara Davis
Building and Project Design Consultant

Sara Davis has more than 15 years of experience in sales and customer relations and currently specializes in commercial aviation and the automotive industry. She acts as a liaison between the customer and Legacy, bringing all parties to the table to streamline and enhance the purchasing process. Her buildings include Ontario Airport, AGC Automotive, Rota Naval Base, and US Steel.