Fabric structures have evolved over the years and continue to grow in importance today.
By Sam Armijos, AIA
Fabric structures have been used in one form or another in different market segments and in a variety of environmental conditions. These structures have evolved over the years with advances in materials and technology, and continue to grow in importance today.
Architectural fabric structures—also referred to as tensile membrane structures, textile buildings, or fabric roofs—come in a variety of shapes and sizes. They can be inside, outside, permanent, temporary, large, small, air-supported, air-inflated or tensioned. These unique forms continue to play a significant role in contemporary architecture, interior design and special events since the time when they were introduced to the world in the 1960s by the noted German architect and engineer Frei Otto.
Today’s fabric structures are designed and constructed independent of geography. They transform space and have both a fun and elegant quality. Besides providing basic shade, signage and shelter, fabric structures serve to complement amphitheaters, sports stadiums, airports, courtyards, building faÃ§ades, interiors, housing, parks, waterfront areas and more.
Designing fabric structures so that they hold up under a variety of conditions can be a complex task. Each component is both visible and structural, and relies on all parts to function properly.
Today’s architectural fabrics and films have been developed to meet the need for materials with high tensile strength, long life spans and a high modulus of elasticity. The finish coating applied to the material seals the fabric against weather and dirt, provides resistance to UV light, serves as a medium for joining panels and incorporates fire-resistant properties.
The most important quality in choosing a material for a fabric structure is its fire resistance. National Fire Protection Association (NFPA) 701 is the most common fire test for textiles and films. The American Society for Testing and Materials (ASTM) is another recognized standard for a wide range of materials, and ASTM E-84, 108 and 136 are common tests related to fabrics for membrane structures. Architectural fabrics can be manufactured to vary in translucency from 1 to 95 percent, and in thermal resistance from a rating similar to a single pane of glass to that of a conventionally insulated structure, while still maintaining adequate day lighting.
There are four major trends in fabric structures today: fabric structures designed with sustainability in mind, more modular fabric structures, more retractable fabric structures and more structures that incorporate ETFE.
Sustainability is not always about recyclable content and energy analysis; it sometimes can be understood via simple health benefits. Shading a playground to improve human comfort, covering surface parking to reduce heat island effect or collecting water from a structure are universally understood and are now considered needs rather than wants.
Designers are seeing the benefits of mass producing a simple structure, such as an umbrella that has reproducible component parts. The savings in engineering and shop drawings from this modular strategy lead to cost effective structures and construction.
As simple as the umbrella is, the designer and client more and more wish to see projects that are retractable, and fabric is the ideal material choice. From retractable awnings to retractable roof stadiums, people want roofs that disappear at the push of a button.
Lastly, with the increase exposure of ETFE at world expositions, the Olympics and on the boards of new sports arenas, there is a growing interest in roofs with transparency as well as translucency.