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High-performing retractable fabric canopy offers strength, pliability, style and comfort.
By Peter Katcha
Bal Harbour Shops in Miami Beach, Fla., is superlative in every respect. The prestigious open-air shopping mall has the highest sales per square foot of any shopping center in the world. It features the finest retail establishments in a setting that epitomizes luxury. The latest addition to that setting is a large retractable fabric canopy that features more than 4,100 sq ft of retractable coverage and a width of 52 ft by 81ft when extended. Th canopy is built using SEFAR Architecture® Tenara® fabric and a mechanized retracting structure called En-Fold®.
Manufactured by Uni-Systems LLC, the En-Fold retractable fabric canopy system performs as a true tensile membrane structure when deployed. At Bal Harbour Shops, it utilizes five powerful three-quarter horsepower gear motors to apply 10 lbs/ln inch of pretension on the fabric. Stainless steel cable assemblies along the edges of the membrane assist in imparting biaxial tension on the fabric membrane.
Uni-Systems designers and engineers learned about the characteristics of Tenara fabric in retractable applications seven years ago and have implemented it into several of its systems since. The system at Bal Harbour is a multi-functional, high-tech solution that also happens to be beautiful.
“Now that we’ve worked with Tenara fabric several times, we’ve learned to take full advantage of its every benefit,” says Peter Fervoy, business development manager for Uni-Systems. “Outside of pliability and durability, its light transmission cuts down heat and distills light to provide a comfortable, shaded area where plants can still grow.”
After more than eight months of research and testing, Bal Harbour Shops chose Tenara fabric because it can fold repeatedly without delamination, and because it provides translucency when unfolded. This rigorous testing, along with the Tenara’s existing real-world applications, proved the product’s flexibility, strength, longevity, translucency and ease of maintenance.
The En-Fold system deploys the fabric, gently and quietly, unfolding it until it stretches out completely flat to form a translucent fabric roof. This happens with the push of a button on a wireless remote control. Sophisticated electronics monitor the precise motion and motor torque of the system to ensure the proper level of tension with each deployment of the canopy. This prevents racking, or binding along the five drive beams as the canopy is deployed.
Through a secure internet connection, Uni-Systems technicians are able to remotely monitor the performance of each installation and provide remote technical assistance in the event of a system fault.
The inner courtyard of Bal Harbour Shops incorporates greenery and features an elaborate koi pond with a glass top that guests can walk on. The Tenara fabric filters the perfect amount of light and heat for both, keeping the plants healthy and reducing the amount of algae in the pond.
Tenara is woven from ePTFE fabric and is fluoropolymer-coated, making the PTFE inherent in the material. As a result, it allows more than three times the light transmission of similar fabric materials – 38% versus the industry standard of 12%. It will flex and fold countless times without delaminating or losing strength.
The fabric is inert to UV rays and provides extremely high resistance to material degradation. It is ASTM E84–Class A fire-rated, making it an ideal canopy material for retail space.
The entire retractable roofing system at Bal Harbour Shops is built to withstand wind speeds of up to 90 mph and can be stored compactly if higher winds are expected.
The unique design of the En-Fold system fully resolves all of the fabric pretension forces within the aluminum drive beams and the perpendicular idler beams. This means that the En-Fold does not impose high loads into the surrounding architecture, making it a perfect solution for retrofits in existing structures, requiring little or no reinforcement.
“Busy commercial and retail locations must utilize their space in all weather conditions,” says Peter Katcha, Director, North American sales for SEFAR Architecture. “Having a retractable roofing system that maximizes usage and comfort is critical to improving and prolonging the shopping experience.”
The Bal Harbour Shops inner courtyard project was completed in October 2013.