A vanguard fabric-airbeam-supported structure tops Carnegie Hall.
By Carla Waldemar
It takes a team to raise a structure—at least in the case of a challenging, vanguard installation atop Carnegie Hall in the center of Manhattan.
The renowned, nine-story music auditorium wished to hold its opening night gala under a tent on its rooftop. Installation was the question. Boom trucks on the city streets were not allowed, as was the possibility of contact with any of the historically-preserved building’s surfaces. Add in the challenge of delivering it with no existing loading dock nor generously-sized freight elevator, and that it had to be aesthetically appealing, easy to install and cost-effective.
Fabric to the rescue
“We went to them with a solution that was easier to fit into the necessary elevator, and one which came in at a more reasonable cost—and they jumped on it,” explains Collin Touhey, CEO of Pvilion, Brooklyn, N.Y., the firm that won the contract to design, engineer and produce the unique structure.
Pvilion’s people went to work to partner with Anchor Industries Inc., Evansville, Ind., for the structure’s top; Stamford Tent & Event Services Inc., Stamford, Conn., to handle installation; and Federal-Fabrics-Fibers Inc., Lowell, Mass., to create the vanguard device that made the whole endeavor possible: a fabric airbeam to hold the structure up, without the need for metal supports, which couldn’t squeeze into the elevator nor be boomed up, and which would have driven costs through the roof.
“We started with a situation which seemed very costly: to create a tent on a roof,” Touhey explains. “The solution we presented was not to use aluminum beams, but fabric beams inflated with high-pressure air. It would be not only practical—easy to install—but beautiful and inviting.
“Such high-pressure technology had been developed by us for the U.S. Army 20 years ago, but this would be the first time the device would cross over into commercial use.”
And if it succeeded, it could revolutionize the possibilities of the tent-rental market.
“The airbeam was the kind of specialist engineering that’s part of our core business. It’s designed to take loads of very high pressure in installation. Consider the weight,” Touhey points out. “It takes 8,000 pounds of load—not like just a balloon animal,” he laughs. “Instead, it must be a rigid beam containing lighting, etc.—and as hard as aluminum.”
Federal-Fabrics-Fibers, which constructed the beam, has long had the Army as a client, using the technology to provide chemical/biological protective units since 1998. The U.S. Army has been interested in inflatable shelters for a long time, says Jean Hampel, team leader of the fabric structures team at the Natick Soldier RD&E Center, Natick, Mass. Tents and other structures, for example, need to deploy quickly with minimal personnel.
The problem that plagued the Army for years was finding the right technology to prevent structures from collapsing overnight. In the 1960s, fans had to be used to constantly help the structures maintain air. Heat-welding technology was used in the 1980s, but the seams it created could not stand up to any weather. “Wherever you have seams, that’s a place to have air leakage,” Hampel says.
The search began for a technology that eliminated seams and could move to higher pressures. The solution was fabric airbeams. “They’ve been used in hot areas like Iraq and Israel and in cold zones such as Antarctica and Greenland; they’re so versatile. We’ve built thousands of airbeam shelters since early 2000,” says vice president Michael Hainsworth.
The fabric chosen was a high DSP (density-stable polyester). “It’s our standard material, a proprietary weave poly,” Hainsworth says. “It’s best for the job because it’s extremely flexible once composted to an outer coating layer and can handle dynamics like wind movement.”
That coating layer is a urethane-neopolpyrene blend. “We pre-coat the DSP with a skin of urethane to bond better with other layers. It’s so versatile, useable in operational environments from -40 to 135 degrees,” he says. “That’s why we adopted this particular blend as our standard material.”
Some installation required
Stamford Tents was tapped to devise the rooftop installation. “There were several specific challenges,” says Steve Frost, president: “No loading dock, just a small loading entrance, which meant we had to reduce everything to a 12-foot height, which also meant a traditional tent was out of the question. The tent needed to cover the entire rooftop but not damage the borders—two sides with glass skylights and a third, a very elaborate planter. So it had to be an inflatable structure—an airbeam. The airbeam is 75 feet long, so we folded it in layers—a Z fold—and laid it out to fit within the space.
“Another factor,” he adds, “is that during inflation, the beam tends to shift. But we couldn’t let it. So we designed inflation-retention straps, attached with a series of X-formations, so as it inflated, we could control it and slowly release it vertically.
“Fortunately, we had nine months to identify and solve potential problems. (We’d done tents on roofs before, but none with an airbeam.) The beam fills relatively slowly, but until it reaches the designed pressure, there’s no structure. So you have to get it to structural pressure in a short time, but from three to 19 pounds takes six hours. Therefore, during the process, we had to switch from a low-pressure to a high-pressure compressor.
“We spent lots of time with Pvillion,” Frost continues, “looking at the ‘what ifs’ and how to solve and identify solutions. We did two preliminary trials on ground-level.”
Another hurdle, Touhey notes: “We had to obtain all city permits, working with a historical landmark. It required coordinating permits for wind, engineering, foundation, etc.” The fortunate result: “It’s new, technologically defiant and exciting,” he says, “and it contributes to a new image for Carnegie Hall—a break from tradition, which is a selling point for them.”
What does this new fabric-formed beam mean for fabricators and renters of tents? “It’s a great future!” says Hainsworth. “It’s a unique product that’s so easy to deploy and operate—less time and manpower required on their end. We’re already talking to Lowell, Mass., about a decorative shelter—self-deploying, so it goes up in minutes.
Touhey is enthusiastic. Will it open up new markets? “Absolutely!” he exults. “It will innovate the tent-rental industry, decreasing labor required to install (always a costly factor) and to transport—no cranes on the street. It will break through tent rental,” he predicts. “We’ve proved that the technology works, so we can create hundreds of large-scale, more affordable units. We have a couple of customers in line and are expecting many more.”
The Army is also interested in commercializing projects such as this one, Hampel says, so these companies the military depends on can stay in business and thrive. “It’s important that not only the companies are healthy and profitable, but also that the commercial marketplace benefits from a Department of Defense investment. It benefits not only the solider but the industry, and the rest of the country and other taxpayers can enjoy this technology as well,” she says. “The reliability is very good. From having tents that could not stand up overnight to this, it’s the ultimate achievement that we’re confident enough in this technology for it to be used for a public event.”
From warehouse to rooftop
After multiple attempts to create inflatable shelters that could stand up overnight, the U.S. military was in need of a technology that would allow a seamless tube to have even tension surrounding it when inflated—and Zvi J. Horovitz, the late founder of Federal-Fabrics-Fibers Inc., Lowell, Mass., had an idea. In 1991 Horovitz rented space in an abandoned warehouse that was home to an old circular weaving machine, which inspired him to develop a computer-controlled device he used to weave a curve into a tube—thus developing the innovation behind airbeam technology.
Carla Waldemar is a freelance writer and editor based in Minneapolis, Minn.