British fabric structures manufacturer Tectoniks is all set to help—bring on the disasters.
By David Littlefield
Post-disaster accommodation has changed little over the years, and it is easy to bring to mind row upon row of tented structures that spring up to provide quick, temporary and low-cost shelters for people with nowhere else to go. David Kelsall, the technical director of a UK firm that designs and fabricates inflatable buildings, thinks he can offer a far better solution.
Kelsall is the co-founder of Tectoniks, a Shropshire, England-based company set up by a small group of people who had worked at Lindstrand, a manufacturer of high-performance hot air balloons. Although Lindstrand had experimented with inflatable buildings, the focus of the company was always going to be flight; Kelsall et al saw a gap in the market and struck out on their own in 2006. Since then, Tectoniks has managed to accumulate a number of significant clients, including Sony and European soccer body UEFA. Typically, its products are limited to events enclosures, as they are both eye-catching and quick to assemble. In May 2009 the company notched up its most significant project to date: an inflatable dome, 35m in diameter and 17.5m high, which it believes is the largest structure of its kind ever made.
For some time now, Kelsall has been looking into how inflatable technologies can transfer to the disaster relief sector, and the result is a set of designs that can provide shelters the size of a generous classroom that can be inflated in approximately six minutes. “We’re pretty confident that what we’ve got is the way forward. There’s nothing that can compete with the speed with which an inflatable can be put up, and added to that is its portability. An entire 5x10m module could fit into the trunk of a hatchback,” says Kelsall.
Tectoniks’ disaster relief shelters benefit from the same materials and underlying technology as its other products, but there is one crucial difference. Where most of its inflatable structures are composed entirely of air-filled fabric tubes, nestled up against each other as corrugations, the disaster accommodation uses inflatable tubing for the structure only. The “walls” and “roofs” of these units are composed of a single layer of fabric. The principal is much the same as the canvas which stretches over the metal frame of a tent, only in Tectoniks’ case the structure and the envelope are bonded together as a single unit.
The reason for limiting inflatable technology to the structure is simple: It uses far less power than that required to fill an entirely inflatable building. In fact, Tectoniks is close to completing a prototype solar-powered inflation device that could, it is hoped, inflate and maintain the air pressure in as many as five 5x10m modules. By ensuring air pressure is kept at around 1.5 to 2psi, Kelsall says these buildings have the same rigidity as an aluminum-framed marquee and just as much resistance to wind and snow loads. A key difference, compared with a marquee is that Tectoniks’ buildings don’t require guy ropes to maintain their rigidity, only stakes that secure the structure to the ground at specially strengthened anchor points.
Kelsall has developed rectilinear and barrel-vaulted versions of this structure, but both are almost exactly the same size. At around 3m high, they are spacious while integrated windows of clear PVC admit plentiful natural light. Moreover, the structures can be linked to form a series of interconnecting rooms. The Red Cross has already deployed two rectilinear units in Croatia, but Kelsall is keen to stress the extent to which the basic designs can be customized. He can imagine, for example, employing fabric of different properties so units of varying opacity or reflectivity can be matched with different climates. He is even considering a double-skinned structure, allowing lightweight insulation to be inserted between the inner and outer layers.
The problem, though, is foresight. Kelsall has every faith in the ability of his buildings to surpass the performance of their more conventional rivals in terms of speed, efficiency, portability and size. The technology behind them, too, is robust and well-tried. Made of “preconstraint” PVC-coated polyester from French architectural fabric manufacturer Ferrari, the complex forms of these structures are designed and cut using a combination of 3-D and 2-D computer software. Seams are heatbonded and backed with tape of the same durable fabric, so Kelsall is confident of the “dimensional stability” of these structures. They won’t stretch or rip, in other words. But they aren’t quick to manufacture, so planning on the part of emergency relief agencies needs to be done in advance. “They tend to be quite reactive, and wait for a disaster to happen. Then they ring and ask for 200 units by next Thursday,” says Kelsall, who can think of two occasions over the last couple of years when this has happened. As a rough guide, 50 of Tectoniks’ structures would take 10–12 weeks to manufacture, which is obviously far from ideal if shelter is needed immediately. Pre-need ordering, then, is key. The only predictable thing about disasters is their unpredictability.