While PTFE (Teflon) can certainly be considered a bit of a miracle material, and has certainly had a significant impact on our lives in it’s own special non-stick way, architecturally speaking it has become something of a second fiddle to a close relation, ETFE.
Ethylene tetrafluoroethylene, or ETFE for those of you have trouble pronouncing words with every vowel (in case you went back, I know there is no “i”), was developed specifically in response to PTFE by DuPont. Not usually the type to leave well enough alone, not long after recognizing the myriad benefits of Teflon, began the search for closely related chemicals that may provide even more appealing characteristics.
They hit paydirt in the 70’s when they developed ETFE, primarily because it had a higher mechanical toughness. That may not sound like much, but ETFE is actually strong enough that it could be extruded into thin sheets fit for architectural application without having to be applied over fiberglass. This not only simplifies the manufacturing process, but it allows the material to maintain recyclability, and possibly most importantly to users, it allows the ETFE to maintain its visual characteristics which are more transparent than my birthday suit.
Okay, it’s not nearly that transparent, more like glass with Vaseline smeared all over it, but you get the point.
Anyway, suddenly, architects have available to them an incredibly strong, durable, and flexible material that can not only take on the role of weather barrier, but can begin to play the role of window as well. All that with only 1% the weight of glass. And that’s when it gets interesting.
The arrival of ETFE in architecture (early 2000’s) also happens to coincide with the rise of complex computer aided design in architecture. Forms that were never before plausible because of impossibly goofy geometry (we’re looking at you, Gehry) could now be handled by sophisticated computer programs. Parametric forms were hot, but the crazy shapes the computer renders still need to hold up to physical construction.
Glass is expensive and challenging to work with outside of the bounds of planar/rectangular elements. With ETFE, architects could now develop buildings with large expanses of unique transparent panels without being laughed out of the office.
The best example of this type of previously-unfathomable transparent blob, is also probably the most recognizable application of ETFE to date: the Beijing Aquatic Center.
Similar to the Metrodome, which became Teflon’s largest application less than a decade after PTFE’s first architectural use, the Beijing Aquatic Center is a large sports facility, and is the largest application of ETFE to date. At over 1,000,000sqft of ETFE, it may remain the largest for some time.
The Aquatic Center is the kind of place the ETFE was really meant for, as it allows for a beautifully complex piece that would be rather impossible without it. The incredible span over the main pool is so large, that cladding the building in glass would have made the roof too heavy to be supported by the wonderfully light structural members. Like the roof of the Metrodome, the ETFE panels are so light that the weight savings is compounded over the entire structure, allowing it to be reduced to the point that the massive structure could easily described as delicate.
While this may remain one of the most fantastic examples of ETFE in architecture, it’s most important contribution may be the doors it opens architecturally. The incredible exposure and critical acclaim it received during the Beijing olympics have given ETFE a level of credibility and glamor that will make it possible for architects to more successfully propose it’s use moving forward. This material will be a genuine competitor to glass in the future, particularly on buildings that call for large swaths of transparency, or for complex and unique form. ETFE has made a big splash, and is poised for some serious disruption.