includes standard 18-inch overhangs, along with gutters and downspouts to assist with water mitigation. By contrast, buildings with curved side- walls have no ability to control rain runoff; water simply runs down the side of the building, potentially causing damage to the foundations or even pooling and seeping inside the structure at the base. Movement of air reduces any maintenance problems from humidity or moisture. Passive ventilation systems, using ridge and soffit vents, rely on the simple movement of warm air; and this passive ventila- tion is a standard feature for some rigid-frame building manufacturers. Additional mechanical ventilation can easily be added to the building frames if necessary. Another benefit from a rigid-frame structure is the ability to handle hanging or live loads. From overhead cranes to fire suppression sys- tems to conveyors, loads can be easily incorporated into the design from the beginning of the project. The I-beams are simply modified in the early engineering stages to account for the intended collateral or point loads. The steel frame and attached fabric can also be designed to handle the environmental factors in a given location, such as wind loads, snow loads, and seismic codes. This is particularly important for buildings located in wide open areas or extreme climates with higher exposure to the wind and other elements. Leading fabric building manufacturers have achieved a number of applicable certifications related to weather, such as Florida Product Approval for high-velocity hurricane zones. The derecho storm that whipped across Iowa and Illinois in August 2020 unleashed winds gusting up to 100 mph over an area 250 miles long. Users of two Legacy rigid-frame buildings in the storm’s path reported that their structures sustained no damage. Trusted Construction Fabric buildings can also be engineered, manufactured and installed faster in the first place. Furthermore, while engineered to be perma- nent, most fabric structures are also designed to be portable if the need arises to move the building later. In some cases, the whole project can be contracted through a single entity. Certain companies in the industry have their own manufacturing facilities on-site to produce everything from fabric panels to I-beams and components. They employ the engineers who work with the cus- tomer to design the building from the very beginning. Additionally, they employ their own in-house professional installation crews, ensur- ing the final construction job is done by those with the proper expertise. By acting as a one-stop full-service shop, these suppliers are able to guarantee quality and workmanship at every step of the process. Ultimately, solid framing materials and better fabric technology wind up contributing to the equivalent of a robust long-term preventive maintenance program. With proven engineering leading the way, purchasers can procure fabric buildings that eliminate traditional head- aches and maintenance, allowing users to focus on the primary aspects of their business.
Legacy offers ExxoTec™ PVC, which features a high-strength woven fabric with additional primer and lacquer layers to provide more du- rability, and an improved warranty to match. This fabric is designed to retain more than double the tensile strength of a standard PE fab- ric and carries a longer life expectancy. These benefits have actually challenged building suppliers to think differently about the uses of the material and expanded the possibilities of fabric building design. Fabric Performance The natural properties of fabric and the way it’s manufactured help to deliver additional performance advantages that reduce building maintenance. Fabric provides a surface area that is leak-proof, ensur- ing superior protection of the interior environment. Users can consider washing down the interior side of the fabric if they want, but otherwise the occasional rainfall will take care of basic exterior cleaning. Just like different fabrics can offer differing life expectancies, the method of installing and tensioning fabric can contribute to differ- ent long-term outcomes and maintenance needs. Older style hoop buildings often had mono-cover designs that involved stretching one piece of fabric over the entire structure. This design makes it difficult to properly tension the fabric and leaves it susceptible to additional movement from wind and snow. This will lead to premature wear, as well as potentially point-loading the structure in ways that it was not designed to resist. Years ago, Legacy developed a fabric attachment system that uses half- inch bolts to secure a keder rail to the top flange of each structural steel frame instead of the industry-standard tek screw method. This method ensures fabric is properly attached and less likely to fail from improper screw installation. The biggest advantage of the system was that it allowed for individual fabric panels – typically 20-feet wide – to be properly tensioned. Each and every section of the roof is horizontally and vertically tensioned in the correct order, which eliminates billowing of the fabric and ensures it remains taut throughout its lifespan. Environmental Concerns Rigid frame tension fabric buildings are ideally suited to reduce main- tenance concerns in other ways as well. Their conventional architecture
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January 2021
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