The Dedmon Athletic Center at Radford University, Radford, Va., is known as “The Bubble” because of its air-supported membrane roof, installed in 1981 by Birdair Inc., Buffalo, N.Y. The roof had outlasted its 20-year expected life, but still needed a retrofit in 2009; Radford University went back to the source, Birdair, for an upgrade. The recently completed composite membrane roof is the world’s first made of Tensotherm™ with Nanogel®, a fabric less than 50 mm thick which quadruples the original roof’s thermal insulation value.
Nanogel, from Cabot Corp., is sandwiched between two layers of structural PTFE fiberglass membrane. The gel inside layer insulates (to an R-12 performance value) while maintaining translucency, allowing natural daylight through (transmission value of 3.5 percent). The durable composite is fade resistant, controls moisture and provides sound insulation, in addition to making it practical for Radford University to air condition the facility. Tensotherm with Nanogel meets energy and building code requirements, and users also get LEED credits in several categories, including insulation, green materials, innovation and daylighting. For more information, visit www.birdair.com.