Legacy Building Solutions has sponsored this post.
Legacy Building Solutions manufactures custom-designed fabric buildings that combine a rigid steel I-beam frame with fabric panels. The resulting open-span structures are able to support loads such as fire suppression systems, cranes, conveyors, HVAC systems and lighting equipment. To date, Legacy’s building installations have been utilized for a variety of applications—with projects ranging from plane hangars and overseas U.S. military bases to storage solutions for 4,000 tons of road salt.
Legacy’s ExxoTec PVC-based fabrics are a primary differentiator for their fabric buildings. Two options are available:
- 28 oz ExxoTec Elite, which is twice as strong as conventional 12 oz polyethylene fabric.
- 19 oz ExxoTec Pro, which is 41 percent stronger than conventional 12 oz polyethylene fabric.
Legacy’s standard ExxoTec Elite option comes with a 25-year warranty, as opposed to the 15 years offered by competing polyethylene fabrics. This warranty is valid in any environment—regardless of whether buildings are located next to the sea (with exposure to ocean spray), subject to hostile climates, or used for corrosive applications such as fertilizer storage.
The Seven Layers of ExxoTec Fabric
Legacy worked with a PVC manufacturing company which operates globally to optimize the performance characteristics of its standard ExxoTec fabric.
“We did quite a number of strength tests on the fabric prior to using it,” said Nathan Stobbe, general manager at Legacy Building Solutions. “Then we worked with our supplier on unique coatings and mixtures to ensure long-term performance of the materials. It was a team effort to develop a superior product for use in our building applications.”
Legacy’s ExxoTec fabric has seven layers:
- The core is a high-strength polyester base fabric that constitutes woven fabric similar to canvas.
- A thick layer of PVC primer coating is applied to both sides of the base fabric, creating a membrane that doesn’t allow moisture through.
- The PVC primer coatings are further reinforced with PVC top coatings.
- The fabric is finished off with a lacquer coating on each side, which prevents plasticizers from migrating out of the fabric. These lacquer layers also create a slippery surface that gives the fabric its self-cleaning properties and minimizes UV degradation.
Legacy’s Fabric Attachment System
When converting rolls of fabric to the covers that go on buildings, the Legacy team first lays the fabric out on the floor to cut, trim and weld pieces together. Once the desired panel size is reached, accessory items such as pockets, flaps and other connecting pieces are welded onto the sheet of fabric.
Unlike conventional fabric hoop buildings that have fabric attached as large sheets on end frames, Legacy employs a patented fabric attachment system where smaller fabric panels are individually attached to each framing member. The fabric panels are tensioned independently of one another using biaxial tension, ensuring a wrinkle-free finish.
“One critical piece in fabric buildings is ensuring that the fabric is tight for the life of the building,” said Stobbe. “That’s one of the areas that the industry has struggled with as a whole. Legacy’s fabric attachment system allows us to tension the fabric in the correct order.
“An individual panel is first tensioned up over the roof system. It is then tensioned width-wise so that it has significant tension in both directions. That allows us to never have to re-tension that panel, and for it to remain tight during the entire lifespan of the fabric. This is a key advantage, both from a long-term performance standpoint and from a safety standpoint—because the entire framework is fully in place before any fabric is added during the installation process.”
Top 10 Advantages of ExxoTec Fabric
1. High tensile strength and exceptional long-term weathering
Legacy’s standard fabric has a grab tensile strength of 745 pounds per inch, making it twice as strong as standard 12 oz polyethylene fabric.
Along with its greater initial strength, ExxoTec Elite can retain 91 percent of its strength after 13 years of exposure to the elements. In fact, strength weathering tests have shown that even after 13 years of weathering, ExxoTec Elite fabric was found to be more than three times stronger than 12 oz polyethylene fabric after a four-year equivalent of accelerated weathered testing.
“The higher the strength and the longer the performance of that strength, the better the value for the client,” said Stobbe.
In addition to traditional fabric strength tests, Legacy performed a test using a 10,100-lb skid loader on a tensioned panel of 28 oz ExxoTec Elite PVC fabric. This fabric was attached to a steel frame using Legacy’s patented attachment system. The test represented the durability of not just the fabric, but Legacy’s entire building system including the steel frame, keder rails, bolts and tensioning. (In the video below, note how the welded seam of the fabric panel demonstrates a strength equal to the fabric itself.)
Not only did the ExxoTec Elite fabric withstand the load of the skid loader—to everyone’s surprise, the fabric fully rebounded in less than 24 hours.
“We thought we had stretched it beyond its capacity, but it turns out we hadn’t,” expressed Stobbe. “The fabric self-healed, and basically pulled itself back together and re-tensioned out. It was as tight as before we started testing, and really all that was left was the dirt from the tracks on the skid loader.”
2. Ability to survive in hostile environments
As Stobbe put it: “No environmental loads are going to be as great as driving a skid-steer on that fabric.”
ExxoTec fabric is proven to withstand extreme weather conditions such as wind (including hurricanes and tornadoes), heavy snow loads, hail, high seismic activity (ASCE 7), cold weather and continuous UV exposure.
“We’ve done testing as it relates to wind load, in particular,” described Stobbe. “One of the parts of the world that is notorious for having hurricanes and very high wind loads is Florida. Florida building code requires extensive testing to be able to prove that the performance of building materials will be able to meet up to those hurricane loads. We did hurricane testing on the fabric, which included putting extreme wind loads and shooting two-by-fours at the fabric out of a cannon. (The simulation is of material flying through the air during a hurricane.) We passed all the tests, and Legacy does projects in Florida on an ongoing basis.
“The reality is that if you were to punch the fabric, it responds more like punching a trampoline. Ultimately, if a metal-clad building was in a big hailstorm or had debris flying around, the chances of that building getting punctured are much higher than if it’s a fabric building. The fabric is able to give and stretch a little bit and can actually resist a lot of puncture-type events.”
3. Translucency
With up to 12 percent translucency, Legacy’s white ExxoTec Elite fabric on a non-insulated building lets in plenty of natural light, allowing for energy costs to be circumvented throughout most of the day.
“On a sunny day, it feels like you’re outside,” said Stobbe. “The miracle of fabric—particularly white fabric—is that it allows light to come through while reflecting heat, which is not something that occurs in things like windows. It really is the ultimate in terms of building material. You have this natural light glowing through from all sides so that you don’t have a lot of shadows or dark corners. A lot of our facilities are used for riding arenas or warehouses—and the natural light makes it really great to be able to work in. Whether it’s people or animals, we all like light.”
In insulated buildings, bright white lining further magnifies the light inside the building.
“You have that white surface on the inside frame of the building, so you don’t see all of the structure,” explained Stobbe. “You just have this nice, clean, white reflective surface that distributes light. So, you can even light a facility using indirect lighting where you shine your light up at the membrane and it will bounce back and provide indirect light anywhere in the facility. It takes less light to provide a really superior, well-lit environment within the building.”
4. Energy Efficiency
In terms of energy, fabric structures have some clear advantages. PVC fabric cladding is thermally non-conductive, meaning the temperature inside the building is cooler in the summer and warmer in the winter. In contrast, a traditional metal or wood building transfers a lot of heat or cold into a building over the course of the seasons.
“Metal is a very conductive material, and so it minimizes the overall benefit of insulation,” said Stobbe. “Fabric—particularly white fabric—has non-conductive properties, and therefore enhances the performance of insulation in the building.”
5. Repairability
In case someone drives the business end of a forklift through the side of the fabric building (“Believe it or not, it happens.”), the ExxoTec fabric is conveniently repairable. A new fabric piece can simply be welded on top of the damaged panel to create a panel with double thickness.
“It’s like putting a patch on your jeans, except instead of sewing it you’re welding that patch over top,” explained Stobbe.
6. Corrosion-free
Although it may go without saying that fabric doesn’t rust, that’s not the whole story. Of course, when contrasted with metal-clad buildings, fabric exteriors simply don’t rust. That said, many of the environments where Legacy installs buildings are highly corrosive—salt storage, mining chemical storage, fertilizer storage—so fabric cladding that doesn’t rust is key to the long-term performance of the building.
Some customers also use interior fabric liners to protect the existing steel frames from corrosion. In many instances, the ExxoTec interior liner is the first line of defense against corrosion. For example, with fertilizer storage, the dust from the product gets on everything and aggressively corrodes metal surfaces. The fabric liner can prevent that contact by sealing the frames off.
Legacy also uses their own proprietary epoxy coatings as a line of defense in corrosive environments.
7. Flame retardancy
Legacy’s PVC fabrics are flame-retardant, and meet standards set by the California Fire Marshal, ASTM, National Fire Protection Association (NFPA), Underwriters Laboratory of Canada (CAN/ULC), Uniform Building Code (UBC), Federal Aviation Administration FAR 25.863(a), and Europe’s EN 13501-1 and DIN 4102. Unlike non-flame-retardant polyethylene fabrics, all ExxoTec fabrics are self-extinguishing, and thus do not add to the fire. The fabrics also showcase a Class A rating when subjected to the ASTM E-84 smoke development test, which studies the amount of smoke that is developed from the fabric during a fire.
“When a flame hits ExxoTec fabric, it does not burn or contribute to the fire,” asserted Stobbe. “The fabric shrinks away and allows the flame to pass through it. The benefit in that situation is that smoke and heat can leave the building. Most damage in fires is caused by smoke and extreme heat.”
ExxoTec’s flame-retardant elements are a permanent feature of the fabric, and endure for the fabric’s life without additional maintenance being required.
8. Cleanliness
ExxoTec fabrics’ lacquer coatings protect the material from pollutants, while creating a slippery surface that self-cleans in the event of rain or snow. Like the fabrics’ flame-retardant properties, these acrylic coatings are a lasting feature of the fabric.
In the absence of rainfall, the fabric can simply be cleaned using mild soap and water.
9. Recyclability
At the end of their lifecycle, ExxoTec PVC fabrics can be recycled into other products.
10. Incorporation of different colors and logos
Legacy’s ExxoTec fabrics are available in five standard colors: white, navy blue, green, tan and gray.
“There is also an option to get custom colors at an additional cost,” said Stobbe. “You can pick any color in the color chart; we just have to formulate that color and apply it to the base coatings.
“One of the easiest things is incorporating logos. Sign companies all over North America use vinyl graphics that can be stuck right onto the PVC fabric. We’ve done huge logos on buildings in very simple ways, just using your regular sign company.”
Conclusion
Due to the above benefits, Legacy’s ExxoTec fabrics provide excellent long-term performance while remaining cost-competitive with polyethylene and other PVC fabrics.
“ExxoTec is comparative price-wise to polyethylene fabrics and other PVCs out there,” said Stobbe. “We work very closely with our supplier to provide both quality and product value in our fabric. Our 25-year warranty, generally speaking, is very good in the building industry.”
To learn more about Legacy’s fabric buildings, visit their website.