Duvall performs dynamic shade studies prior to settling on a design so the client can see the impact of the time of day on the structure. “I try to organize the structure so it’s functional over the course of a year,” he says. “You can think you’re solving a problem by putting fabric over a large area but if you don’t pay attention to the angles, it’s ineffective. You can move a flashlight over a physical model to act as the sun, or you can use software to see where shadows and sun are cast at any given time of day.”
On the cutting edge of fabric structures with light transmission properties is ETFE—Ethylene Tetra Fluoro Ethylene. “A core part of our business is designing, manufacturing and installing ETFE systems,” Jason Smith says. “It’s a totally different kind of system than woven-base cloth fabrics, such as PVC or PTFE. The ETFE copolymer is extruded into thin films (or foils), which are used to form either a single-layer membrane or multi-layer air-filled cushion. A lot of our clients want ETFE because of its light transmission—up to 95 percent as a single layer.”
ETFE weighs 1 percent that of glass and has similar light transmission capabilities. It’s popular with general contractors because the steel work and foundations normally used for support can be dramatically reduced to support ETFE. The product can be specified in up to five layers. The space between layers is filled with air from an air handling unit that requires about the same amount of electricity it takes to power a 100-watt light bulb for one day.
With Landrell’s Intelligent Printing option, end users can manage the amount of light that enters a space by increasing or decreasing pressure in the cushions. The top and middle layers are printed with an opposing pattern. As the air pressure decreases, the printed layers come together, reducing the light transmissions; as it’s increased, the patterns “open up,” allowing light in.
Sigrid Tornquist is a freelance author and editor based in St. Paul, Minn. She is also the associate editor of InTents magazine, a publication of the Industrial Fabrics Association International.
Three ways of managing sunlight with ETFE systems
Printing: Also known as fritting, the surface of the foil is covered with a variety of patterns to reduce light transmission. By varying the percentage of coverage and density of the ink, light transmission can be altered.
Pigment Coloring: Foils can be tinted in any color and at varying degrees of opaqueness to reduce light transmission, color wash a space and provide branding.
Intelligent Printing: This three plus-layer system allows end users to change light levels by adjusting air pressure in the fritted cushions, which overlay one another.
Source: Architen Landrell