The development of tension fabric, in connection with advancements in steel cable structural systems and mechanically induced air pressure, has led to its relatively recent incorporation into structures all over the world. Due to its internal structure, tension fabric has tremendous implications for the form, internal environment, and environmental adaptability for a particular structure.
Exterior Form and Aesthetics
As stated previously, the shape into which the tension fabric is placed is extremely important to its overall stability. The anticlastic and synclastic shapes needed for this stability pose exciting new possibilities for architects in the conceptual design phase and civil engineers in designing structural systems. In order to support the tension fabric in these fantastic shapes, a positive air pressure created by mechanical systems or a series of cables and structural steel must be utilized. However, due to the extremely lightweight nature of the tension fabric, the cost of materials is greatly reduced from that of a conventional roof. For example, the Georgia Dome, which has a tension fabric roof spanning over 395,000 square feet, weighs only sixty-eight pounds!
In addition, the actual color of a tension fabric roof adds an intriguing aesthetic to the exterior of the building. While fiberglass base fabrics are almost exclusively confined to a white color, polyester base fabrics can be a variety of colors. Regardless, during the day a tension fabric roof is a solid color that can be seen from miles away. At night, the roof is transformed into a glowing beacon due to the interior lights of the building that shine through the translucent fiberglass or polyester.
The Interior
The translucency and reflectivity of the base fabric of tension fabric roofs have tremendous implications for the interior of their respective structures. The translucent tension fabric roof allows for very little necessary interior lighting during the day in order to illuminate the structure. It also lends itself to interior plant growth and greatly decreases the amount of glare generated from the sun. The reflective properties of these tension fabric roofs have similar positive effects on the interior. First of all, these roofs reflect much of the sun's direct rays, thereby creating a cooler interior to the building [6]. For example, the temperature inside of the Haj Terminal will rarely rise above eighty degrees, even though the exterior temperature can top 120 degrees. In addition, the highly reflective surface of tension fabric allows for more efficient lighting at night. The overall result of all these effects is a marked decrease in the amount of energy needed for the lighting and HVAC (heating, ventilation, and air conditioning) systems of the structure.
Environmental Observations
One of the most amazing properties of tension fabric is that it can be used effectively in almost any environment, ranging from the extreme heat of Saudi Arabia to the frigid cold of St. Paul, Minnesota. While it is often necessary to add a thermal lining or double layer of the fabric in colder climates, the material is surprisingly versatile. In addition, tension fabric is considered a 'limited combustible' material. While it will catch on fire in the presence of a flame, this flame will die out as soon as the source is removed. Finally, maintenance of tension fabric roofs is incredibly simple due to tension fabric's self cleaning properties. All that is necessary to clean off any unwanted material is to rinse it off with water.
Despite its more extensive use over the past decade or so in architectural applications, tension fabric is still a relatively new building material. Discovering necessary forms and amount of pre-stressing can be extremely complex, sometimes only vaguely understood, and therefore much care is taken in designing structures involving this material. However, the advantages of tension fabric can not be disputed. It is an incredibly lightweight, material saving, energy conserving solution for roofing systems, especially over large areas. In short, it is an excellent option for architects and engineers looking to design sustainable structures.
Source: illumin