advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...

Advanced Building Skins
The exterior layer of fabric is breathable so as to prevent any water from penetrating, yet still allow
water vapor to pass through. This is required in order to allow water that has entered into the first
cavity to evaporate back out. The interior two layers are composed of fully transparent plastic ETFE
foils so as to allow maximum light penetration. These two layers function as a retainer for the
insulation while also performing as a vapor barrier. The distance between the two inner layers can be
adjusted to provide more or less space for insulation, depending on the performance requirements.
Between the two inner layers is a transparent insulation, capable of providing high insulation values
while also allowing natural light through the system. This layer of insulation is kept at a minimum in
order to keep the light penetration levels as needed without sacrificing much thermal performance.
The interior-most layer of fabric is once again a breathable one, in this case allowing any water that
has condensed within the system to evaporate out.
3.2 Specific System Design
Tensiwall is characterized by easy replacement of the membrane in case of failure or at the end of its
life, minimal use of materials, very thin profiles, minimization of thermal weak points, and high
recyclability. All of these qualities have been carefully designed into this specific Tensiwall system,
allowing it to excel above other advanced facade systems of today. In order to maximize the thermal
performance of this system, the length of the panel is in the vertical direction; in order to further
advance the lightweight aspect of the design, Tensiwall uses the lightest materials possible throughout;
and in order to push the recyclability of the system, only 100% recyclable materials are used (other
than glass).
In order to achieve the thin profiles, this system is designed to function in different configurations for
the various stages of installation. Once installed, each panel is attached to the adjacent ones,
essentially equalizing lateral forces that the stretched membrane exerts on the frame. Since movement
of the panels must happen at the head and sill conditions due to dead and live loads, this idea of force
equalization happens only at the jamb conditions. A thinner profile at these conditions means a
reduction of one of the weakest thermal points in the system. Therefore the panel is oriented in its
vertical position in order to take advantage of the thin profiles, minimize the weaker points in the
system (the head and sill conditions), and maximize the thermal performance. The frame, however,
must also be stable during transportation when it is not engaged with the adjacent ones; therefore, the
concept of Tensiwall is that the frame at the jamb conditions are allowed to rotate. This allows the
depth of the jamb to be optimized whether the textile panel is in transport or installed.
As a result, the frame vertical mullions are always aligned to distribute the forces in the most efficient
manner. During transportation, the member is aligned with the tension force of the fabric layers. Once
installed on the building, the mullions engage each other, allowing the textiles to equalize the forces
running through themselves. With this strategy, a very thin framing member can be achieved while
still providing enough stability to resist the lateral forces of the tensioned fabric. See Figure 7 for an
illustration of the design concept behind Tensiwall.
TRANSPORTATION
INSTALLATION
Figure 7: Tensiwall Design Concept
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