Tents, Sails, and Shelter: Innovations in Textile Architecture

Tania Garbe

Editor Werner Lang Aurora McClain

csd Center for Sustainable Development II-Strategies Technology

2 2.14 Innovations in Textile Architecture

Tents, Sails, and Shelter: Innovations in Textile Architecture

Tania Garbe

Based on a presentation by Dr. Jan Cremers

Figure 1: Center for Gerontology in Bad Toelz,

Introduction tecture and inspire exciting new forms.

As designers we are continuously confronted Membrane materials and applica- with sobering statistics about the built environ- tions ment and the severity of its contribution toward CO emissions and resource depletion. We 2 History know that building construction uses 17% of the world’s fresh water supply, 40% of its fossil Building with membranes is not a new art. fuels and manufactured materials, and 25% of Creating shelter from textiles or animal skins 1 the world’s wood harvest. As a result, contem- was one of the first methods that humans porary designers have become increasingly devised to protect themselves against the ele- committed to ecological design principles with ments. Ancient cultures used textiles first for the intention of producing a built environment clothing and then for tent structures, creating that is more in tune with its natural surround- basic shelters from simple membranes. Some ings. Construction materials are constantly cultures even developed highly elaborate being reassessed and redesigned to be more structures from combinations of membranes, sustainable. Textile structures can play an like the Mongolian gers. In modern architec- important role in sustainable architecture, ture, fabric was utilized predominantly for stepping lightly on the land while using fewer shading devices and temporary structures. It material and energy resources for fabrication was not until the mid-twentieth century that 2 and shipping. designers like Frei Otto in Germany began try- ing to optimize membrane structures in order Textile architecture has the potential to reduce to create long-lasting buildings. More recently, solar gain, cooling loads, and peak electric- this approach has driven the search for materi- ity demands, resulting in lower energy costs als that can serve multiple functions, providing for buildings. Membranes can be designed to shade while also stabilizing geometries, to be easily dismantled, reducing the amount of create more efficient structures. post-construction refuse. They are extremely flexible, and in combination with photovoltaic Current technologies: ETFE and PTFE/ cells they can even produce their own energy. Glass But perhaps the most welcome architectural contribution of modern textiles is their ability to The advent of and PVC coated transform the aesthetics of sustainable archi- materials has led to innovations in textile

3 II-Strategies Technology

performance that have brought membrane Flexibility architecture into the forefront of sustainable One main advantage of using membranes over design. Recent efforts have focused on the glass is that membranes are capable of span- The lightweight nature of textile materials development of more hi-tech materials based ning very large distances. The benefit is great- affords them a great amount of flexibility in on , like PTFE, poly tetrafluoro- est with fabrics, which are capable of structural their construction and removal. Since mem- ethylene coated glass fibers, or ETFE, a trans- spans of over 200 feet. However, foils can also branes are inherently flexible, they are also parent foil made from a copolymer of ethylene be used to span distances greater than those particularly well suited for use in temporary or and (Figure 2). Teflon is possible with glazing, especially in the horizon- operable structures that can open and close. the DuPont brand name for PTFE, which is tal direction. Membrane constructions can also The ‘Josefsburg’ Kufstein is a castle in Austria known for its durability and anti-stick proper- be stabilized by pre-stressing and pressurizing that hosts several open air concerts per year. ties. As a foil (ETFE) it is also UV transmittant pillow-like cushion structures. For example, Because of the frequent risk of rain, a roof and resists UV degradation. ETFE and PTFE at the Clarke Quay Redevelopment Project in was required that could be closed quickly, have a variety of unique qualities that make , Will Alsop Architects and Hightex even in the middle of a performance. The them desirable for membrane structures and Group used an ETFE film membrane to cover solution was to create an operable structure versatile as an alternative to glass. an old shopping street and convert it into a that can be closed in only 3 minutes (Figure shopping mall. Here, the membranes were 5). For this project the architects chose a new, Light transmittance inflated like cushions, with an over-pressurized very flexible, pure fabric with a interior stabilizing the surface and allowing it to fluoropolymer coating. An additional concern New textile fabrics offer varying degrees of span a much greater distance than normal. If in this project was the stringent building code transparency and light transmittance. Many the cushion size required is very large, a cable requirements for the historic structure. The de- recent architectural applications of textiles can net can be used to further increase the span of cision to use a textile construction ensured that be found in stadiums and sports arenas. Ap- structures. the historic architecture and appearance of the proximately 80% of all new stadium roofs use ‘Josefsburg’ castle would not be dramatically membrane construction. One reason for this is Building image altered. the demand for high light quality in a stadium. Membranes offer an affordable way to provide Textile architecture can also be used to create durable, light-transmitting roof structure. an aesthetically interesting facade. The mate- For example, the Olympic Stadium in Berlin rial’s ability to take on sinuous and unusual received an innovative new membrane roof as forms while still transmitting light makes it part of a retrofit for the latest world cup (Figure well suited to the creation of original facades 3). Von Gerkan, Marg & Partner specified a that help to create a unique image. The textile double layer of PTFE-coated glass fabrics for envelope of the Burj Al Arab in Dubai has be- this purpose. The two layers are separated come iconic, relating the building to an Arabic by a 4.5m gap for technical equipment, while tent at a vast scale (Figure 4). The facade the outermost layer acts as a rain screen. The uses a two-layer PTFE glass fiber membrane, lightweight outer membrane is only 1.5 mm with each piece of fabric measuring 2500 thick, yet is sturdy enough to support human meters square. occupation for construction and repair. Greater Spans Figure 3: Roof of the Olympic Stadium: Berlin, Germany

Figure 2: PTFE and ETFE membranes Figure 4: Burj Al Arab: Dubai, UAE

4 2.14 Innovations in Textile Architecture

Rapid construction energy use for the building (Figure 1). The brane can help to create shade and increase membrane shelters a standard post and rail reflectivity, while printed text or patterns can Another important advantage of textile archi- facade and an external concourse for circula- also add a graphic component to a structure. tecture is that it allows for rapid assembly and tion. The membrane protects visitors from Textiles are also quickly becoming used on construction. Membranes arrive on site as extreme weather along this exterior circulation buildings as an income producing and eye- modular units or packages. Once these units around the building. In this project it was very catching advertising method. In other instanc- are installed, they can quickly be ‘unwrapped’ important to the architect that the membrane es printing or fritting can introduce a sculptural and secured, greatly reducing the time and form an almost invisible skin, allowing a visual and meaningful component to membranes. At cost for construction. connection between interior and the exterior. the M11 Terror Attack Memorial in , an The exterior membrane facade creates a very internal ETFE screen displaying messages to Thermal insulation transparent causeway while creating providing the victims of the attack is suspended from a an intermediate temperature zone that helps to translucent cylinder of glass bricks, acting as One very exciting emerging possibility in reduce energy consumption. the central sculptural piece (Figure 7). Light is membrane engineering is the potential for allowed to filter through the messages and into incorporating thermal insulation. Membrane Form/Sculpture the structure, thereby lighting the underground producers have tackled the challenge of creat- space beneath it. ing thermally insulative membranes with very Another advantage of using membranes high R-values. At the visitor centre for Alnwick rather than glass is that fabrics have the ability Durability Garden, a profile was developed that could to create any free-form shape. This allows clamp together several materials at the same membranes a degree of flexibility that can be PTFE fabrics have remarkable self-cleaning time. In this case, PTFE glass fabrics were appropriate to sculpture or art. One example characteristics and incredible durability, mak- combined with ETFE foil to create a very high is the work of Anish Kapoor, who recently cre- ing them considerably more desirable for shad- level of thermal insulation. Since the system ated a membrane sculpture called Marsyas for ing applications than typical awning materials. used lightweight foils, it required less structure the turbine hall of the Tate Modern (Figure 6). PTFE fabrics stay clean and white for longer, and was able to overcome the safety hazards The piece is 180 meters long and consists of 3 which causes them to have greater reflectivity that are normally associated with having glass rings that act as a framework for a draped PVC over the entire life span of the material. The overhead. If a thin membrane structure were coated polyester fabric membrane. In another beautiful interior light qualities and exterior im- to break and fall, it is unlikely that any harm project, OMA created a massive, helium filled age of the Burj Al Arab would not be possible would be done to the visitors below. Further balloon that served as the roof for a temporary without such a self-cleaning, highly durable, insulative properties can be achieved using structure. The balloon rested on the simple reflective fabric. The same qualities also apply membranes to create thermal buffers or cli- metal walls of the structure at night, but during to ETFE foils. matic envelopes as described below. the day the balloon was partially released so that light could be allowed in from the edges. Low emissivity and infrared mirroring Climatic envelopes Printing/Fritting Low emissivity (Low-E) surfaces are surfaces At the Center for Gerontology in southern that reduce infrared radiation from warmer Germany, a secondary skin membrane was One functional and aesthetic attribute of to cooler surfaces by reflecting a significant used to create a thermal buffer or climatic membranes is that their surfaces can easily be amount of radiant heat.3 This can potentially envelope that moderates temperature and fritted or printed upon. Dot fritting on a mem- raise the R-value, or lower the U-factor value,

Figure 5: Josefsburg Kufstein: Austria. Figure 6: Marsyas by Anish Kapoor: Tate Modern,

5 II-Strategies Technology

of a building envelope made of these materi- it acts like a mirror for long-wave infrared light, extremely flexible amorphous silicon thin-film als. Low emissivity coatings are a standard but not for visible light. solar cells embedded in a fluoropolymer film. technology for glazing, and have now been The resulting photovoltaic cells are only one developed for PTFE glass materials. Innovations in membrane systems micron thick and come as a roll that can be cut to length (Figure 10). These new flexible At the Suvarnabhumi Airport in Bangkok, a Research and development has led to several photovoltaic modules are well suited for use on low-E coated PTFE glass has been used as recent innovations in membrane architec- membrane structures, which often have large an interior layer paired with an outer layer of ture. The most exciting recent developments surfaces with high sun exposure. It is finally PTFE/glass that reflects up to 70% of solar include integrated photovoltaics, translucent possible to put PVs on surfaces that cannot radiation was used on the outside (Figure 9). thermal insulation, standardized elements, and accommodate heavy, conventional, rigid solar The real advantage of PTFE over glass in this functional coatings for membranes. panels. Not only do these systems make it case is that it does not gather any dirt, and possible to produce electricity on flexible sur- therefore its reflectivity remains constant over Integrated photovoltaics faces, but in translucent building components the lifetime of the product. Other materials they can also reduce the solar heating by get dusty, making them unable to maintain The world’s first flexible photovoltaic modules providing shading of interiors and thereby mini- the same reflectivity over time, which is integrated into high performance membranes mise cooling loads and energy consumption. crucial to the energy balance of the building. have been developed in a product called PV The membrane architecture of the Bangkok Flexibles (Figure 9). Until recently, PVC was Translucent thermal insulation for airport consists of three layers, each of which the only transparent membrane that was seri- membranes is 10810,000 square meters in area. The ously studied for integration with photovoltaics. designers chose to condition only the spaces Unfortunately, PVC has proven to be unus- Because of the low material thickness of mem- used for human occupation, thereby reducing able because of its relatively poor durability brane structures and the high levels of light the required cooling loads. Since very high for long-term use. Since long-term use is transmission frequently desired, high thermal temperatures occurred in the upper areas of essential in PV applications so that users can insulation has previously been difficult to the membrane canopy, it was very important to see returns on their investments, research- achieve with membranes. The most promising apply a low-E coating to the surface facing the ers have found more suitable substrates with solution is the use of translucent silica-aerogel. interior, so that the membrane would not act as longer lifespans. The durable, self-cleaning, Aerogel is a highly efficient thermal a huge overhead radiator. UV-resistant polymers ETFE and PTFE have which also transmits light well. allowed the integration of PVs into translu- Another important quality of low-E PTFE ma- cent and transparent membranes for roofs, Solarnext AG and Hightex Group worked with terials is that they mirror radiation in the same facades, and canopies. PV Flexibles can either the Georgia Institute of Technology on their part of the far-infrared spectrum. This leads be laminated between two layers of an ETFE Solar Decathlon Entry of 2007 to design a roof to an interesting effect in the Bangkok Airport. foil, or bonded to a translucent PTFE mem- that was highly insulative and allowed for high When looking up to the roof, one can feel the brane. They are extremely thin, highly flexible, light-levels within the structure. The solution cold that is radiating from the floor. In this case and very light photovoltaic cells composed of was to create an ETFE pillow structure filled

Figure 7: M11 Terror Attack Memorial: Madrid, . Figure 8: Suvarnabhumi Airport: Bangkok, Thailand

6 2.14 Innovations in Textile Architecture

with Aerogel (Figures 11 and 12). The pillow structures also included an ETFE water- proofing layer, because the structure needed to be frequently assembled and disassembled. The result was an insulative assembly that performs four times better than standard insu- lation. Thermal blankets incorporating Aerogel can also be applied to PTFE glass fabrics, creating very thin material layers with very high insulation values.

Standardized membrane elements

Membrane manufacturers have begun to standardize their membrane components, creating modules that make construction con- siderably easier and more cost efficient. The intention is to create modules that are similar to window units, but made out of membrane instead of glass. One significant advantage that membrane units have over glass window assemblies is that they offer a greater variety Figure 9: ‘PV Flexibles’ integrated in a membrane structure of options in terms of size. Such standardized membrane elements were applied in a project for the Bergwacht (Mountain Rescue Cen- ter) in Bad Toelz, Germany (Figure 13). This building envelope is comprised of around 400 prefabricated, standardized membrane pieces that were assembled on on-site.

Innovative functional coatings

Exceptional properties that until recently have only been available for glass, like low emissiv- ity and selective light transmission, have been developed for membranes. These coatings work with clear ETFE foils. Low-E coatings can also be applied on PTFE coated fiberglass, Figure 10: PV Flexibles: Application Process Figure 11: Section of translucent Aerogel-filled ETFE panels like at the airport in Bangkok. Transparent selective functional coatings are able to reduce the near infrared part of the sun’s spectrum while still transmitting most of the visible spectrum. This technology is particularly useful for translucent membrane structures in hot climates, like the Dolce Vita Tejo shopping mall project currently under construction in , (Fig. 14). In the future, innovations in functional coatings will result in high levels of control over the energy characteristics of membrane materials.

Conclusion: the future of membranes

Textile architecture will play a key factor in the future of intelligent building envelopes, since it can create energy-producing and energy load- reducing surfaces. The role of membranes in a sustainable built environment will continue to change as new advances are made and technologies discovered. Currently, building surfaces and envelopes are often treated only as inert systems that function passively Figure 12: Aerogel-filled ETFE roof panels: Solar Decathlon

7 II-Strategies Technology

to protect us from the elements. However, building surfaces are likely to play a much more important role in the future. Off the Grid: Sustainable Habitat 2020 recently predicted that the integration of electronics and bio- chemical properties in building materials could lead to a shift where building surfaces are thought of as sensitive skins that are ”alive and act as membranes to harness energy.”4 In this role, membranes have the potential to become transporters of air, water, and light, helping to lead the built environment on a path towards energy independence and sustainability.

Figure 13: Architects Thomas Herzog + Partner: Bergwacht Bad Toelz, Germany

Figure 14: Dolce Vita shopping mall: Lisbon, Portugal

8 2.14 Innovations in Textile Architecture

Notes Wright, Bruce N. “Report: Fabric Structures Discussed at Symposium,” Fabric Architec 1. Wines, James. Green Architecture. Koeln: ture, January/February 2008. Taschen GmbH, 2008.

2. Riddle, Mason. “Living lightly on the Land: Further Reading Fabric’s sustainable future may help lead design forward.” Fabric Architecture January/ Burger, Edward B. Translucent Materials : February 2008. Glass, Plastics, Metals. Ed. Frank Kaltenbach. New York: Birkhauser 3. Darling, David. “Low-emissivity (low-E) Verlag AG, 2004. glass.” The Encyclopedia of Alternative Energy and Sustainable Living. http://www.david- Herzog, Thomas, Roland Krippner, and Werner darling.info/encyclopedia/L/AE_low_emissiv- Lang. Facade Construction Manual. New ity_glass.html (accessed October 21, 2008). York: Birkhauser Verlag AG, 2004.

4. Wright, Bruce N. “Off the Grid” Fabric Archi- Koch, Klaus-Michael, and Karl J. Habermann. tecture January/February 2008. Membrane Structures : The Fifth Building Material. Grand Rapids: Prestel, 2005.

Figures Biography Figure 1: Hightex, D-Rimsting 2008 Jan Cremers is the Director of Envelope Tech- Figure 2: Hightex 2008Seer, Ulli, D-Icking nology at Solarnext AG / and Hightex Group, (from “Membrane Structures”, KM Koch/ Rimsting (Germany). Prestel) He studied at the University of Karlsruhe from Figures 3-5: Hightex, D-Rimsting 2008 1991-1999, at which time he received the 1st prize in the building network competition for Figure 6: www.flickr.com by ultrahi the Diploma of the Year. He has also studied Architecture and management at Westminster Figures 7-8: Hightex, D-Rimsting 2008 University, London, UK.

Figures 9-12: Solarnext AG/ Hightex Group, In 2006 he received awards for his outstanding D-Rimsting 2008 doctoral thesis: “Applications of Vacuum Insula- tion Systems in the Building Envelope Alliance Figure 13: Verena Herzog-Loibl, Solarnext of Friends of the Technical University in ” 2008 from both the Technical University in Munich and the Marshall Foundation. Figure 14: Promontorio Architects, P-Lisboa Jan Cremers has lectured frequently at the Technical University of Munich School of Archi- tecture on topics concerning membranes and References facade construction. He is a regular reviewer for the referenced international magazine Solar Cremers, Jan M. “Innovative Membrane Energy, official journal of the International Solar Architecture,” XIA International, January Energy Society. Since 2008 he is a full profes- 2008. sor of Building Technology and Integrated Ar- chitecture at the University of Applied Sciences Cremers, Jan M. „Building Integration: Modern Hochschule für Technik in Stuttgart, Germany. Tent Construction.“ Sun & Wind Energy.“ Mar. 2008: 162-65.

Cremers, Jan M. “Translucent High- Performance Silica-Aerogel Insulation for Membrane Structures.” DETAIL ENGLISH, Issue 4-2008 Plastics: 410-412.

Dzierzak, Lou. “See the Light: New technolo- gies bring light and the message to fabric” Fabric Architecture January/February 2008.

9