Resilient Design

Creating buildings for adaptation to changing climate conditions
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Sponsored by Cascade Architectural and C.R. Laurence Co., Inc.
By Peter J. Arsenault, FAIA, NCARB, LEED AP

A closer look at the attributes of coiled wire fabric systems follows.

  • Material makeup: Coiled wire fabric systems begin with a base metal wire in varieties of steel, aluminum, brass, copper, or stainless steel. The choice of the wire material and its gauge impact the weight, functionality, and aesthetics of the final fabric. By altering the base material, weave thickness, wire gauges, weave pattern, and finishes, the strength, rigidity, and appearance can all be chosen to meet the design or performance characteristics being sought. It is worth noting that the fabric is available in virtually unlimited widths and up to 40 feet in length, so large installations can be achieved with a single panel in many cases. For projects needing more than a 40-foot span of fabric, multiple coils can be spliced together at the job-site in a routine fashion and still create a continuous or seamless appearance.
  • Design concepts: Coiled wire fabric is used as a highly decorative design element that adds dramatic and elegant screening to exterior and interior applications. It is highly customizable and available in virtually unlimited finishes. Coiled wire fabric is available in either a natural, uncoated state or with resilient powder-coating finishes for a sharp, long-lasting, durable aesthetic. This means that the color choices are broad, allowing it to be a successful part of virtually any design scheme. Further, the finishes can be specified with low VOC content to protect against that exposure when used on interiors. In fact, some coiled wire fabric products carry Declare labels with the International Living Future Institute.
  • Attachment systems: The means of attaching the wire fabric to the building can be done in a variety of ways and with a variety of appearances. The material can be left to hang (i.e., flowing freely), secured at both the top and bottom, or even be pulled taut to create a semi-rigid condition. Because of its fabric nature, curved and undulating shapes are easily achieved, providing facades and interiors with more character and vitality than rectilinear shapes alone. Products are available in either fixed or movable configurations along track attachment systems that are engineered to fit the precise aesthetic and performance requirements of a project. Many attachments are offered in aluminum, steel, or stainless steel and are available with optional ceiling, wall, or suspended mounting systems. Engineered attachment systems can be manufactured flat or undulating to varying degrees, then finished with the coating or color of choice.
  • Performance traits: From a resiliency performance standpoint, coiled wire fabric can be used as an element across a full facade in coordination with other building enclosure systems to protect otherwise vulnerable components. In appropriate strengths, it can provide partitioning for safety, fall protection, blast mitigation, and security. As a material added to a building, coiled wire fabric is a long-lasting and durable product requiring minimal if any maintenance. The open nature of the fabric is such that it can be used for solar shading, which can contribute to energy savings. It can also be used for lighting effects (i.e., illuminated with wash lighting) or light diffusion to further enhance the interior ambient lighting of a space.
  • Retrofit applications: Coiled wire fabric is light weight making it easy to work into a retrofit or renovation project. This is particularly useful in the case of needing to reinforce and protect facades or other building areas from threats of severe weather or other concerns. The gauge of the wire and the spacing of it will determine the overall strength, which can then be selected to suit a particular retrofit condition.
  • Light transparency: The nature of the coiled wire fabric is such that it will allow light to pass through, which is often desirable for many interior design applications. How much light and how visually transparent a certain product appears will be based directly on the makeup of a particular fabric. Those with thicker wires and tighter weaves will obviously allow less light than those with thinner wires and more open weaves. Architects and designers can play with the material’s level of transparency by altering these factors to suit their needs to create a material that is simultaneously open and closed at the desired levels. As such, it is sometimes used over windows, as a diffuser for natural daylight, or as room separators where light is intended to be shared. “Fullness” is another factor that designers can alter that will vary the level of light able to pass through the coiled wire fabric. By using more material than what is required to cover a given area, a billowing drapery effect may be achieved, causing the mesh to overlap which can be used to control the light.

When selecting a coiled wire fabric system for a project, it is important to recognize that there are a lot of different choices in the details of how it can be specified. Manufacturers will readily work with architects and designers to review the specific project requirements and suggest standard options or even engineer a custom solution. Some even offer specific services to support the use of their products, including structural engineering, mechanical engineering, extrusion design, FEA analysis/modeling, drafting, shop drawings, schedules, specifications, fabrication, and on-site installation consultation.

Images courtesy of Cascade Architectural

Coiled wire fabric can be attached to the interior or exterior of a building using a wide variety of available attachment systems.

Testing for Resilience

While all of the foregoing characteristics are appealing for general building use, the question at hand is how well does coiled wire fabric work in terms of resilient design. The University of Ottawa in Ottawa, Ontario, Canada, took on this question in July of 2015. It conducted a series of experiments using a shock-tube apparatus that simulates an explosion or blast and records the intensity of that blast. The shock tube is connected to a chamber that has a test wall constructed on the end. That test wall can then be subjected to a shock wave (blast), and the results of how it reacts can be recorded.

Specifically, the University of Ottawa testing looked at using coiled wire fabric to protect two different wall conditions: an unreinforced masonry (CMU) wall and an aluminum-framed, fixed-glass window. Each wall condition was tested with two different coiled wire fabrics to determine the degree of protection that the fabric did or did not provide during a blast event. The protective coil fabric system had either 14-gauge or 16-gauge wire coils. All wire fabric had a weave size of 38 inch.

In particular, the testing was performed to see to what degree the wire fabric would contain the fragmentation of either the unreinforced masonry or the glazed windows. In this case, the criteria was to determine the suitability of the fabric according to federal GSA guidelines for blast protection at facilities of the U.S. government. That criteria classifies protection based on measuring how high the debris or fragments of building component (wall, glass, etc.) are thrown above the ground at specified distances out from the facade based on the graph below.

Image courtesy of Cascade Architectural

As shown, the lowest hazard (highest protection) occurs when a blast produces debris that is thrown and falls on the ground no more than 3.3 feet (1 meter) from the blast edge. A low to medium hazard (low to medium protection) exists if the debris falls within 10 feet (3 meters) of the blast site at a height of no more than 2 feet (0.6 meter) above the ground. A high hazard condition (least protection) applies if the debris is thrown 10 feet or more at a height of more than 2 feet (0.6 meter) above the ground.

In the University of Ottawa testing, each test sample was subjected to a single destructive pressure-impulse combination generating high-velocity projectiles. The coiled wire fabric was installed on the unloaded/interior side of the nonstructural walls and windows. The results of each of the four tests indicate that the coiled wire fabric performed well and suffered relatively minor damage that did not impede its intended protective function. The fabric contained the entirety of the unreinforced masonry block walls and prevented potentially life-threatening projectiles from penetrating the test area. It also contained the entirety of the large glass fragments within the first meter of the windows. The pieces of mortar or glass that penetrated the test area were limited to the weave size and did not pose a life safety hazard. As such, they demonstrated the highest level of protection in most cases according to the GSA criteria, with at least a low to medium protection against the smallest fragments that may have passed through. Furthermore, there was no damage observed to the attachment system used to secure the fabric. However, local yielding and uncoiling of wire along some points of the attachment were observed accompanied by minor elongation of the fabric along the vertical centerline. These minor deformations did not compromise the protective qualities of the coiled wire fabric.

Photos courtesy of Cascade Architectural

A series of blast tests were performed on wall and window assemblies with coiled wire fabric covering the outside. In all cases, the fabric performed well and suffered only minor damage.

Overall, coiled wire fabric is shown to provide a protective solution for preventing further building damage and harm to people in severe conditions. It also has the capability to do so in a manner that can be readily integrated with the building design for a cohesive, appealing look.

 

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Originally published in Architectural Record
Originally published in March 2020

Notice

Academies
Resilient Design
Buyer's Guide
Fabricoil® Coiled Wire Fabric Transforms Parking Garage
Cascade Architectural provided the fully engineered Fabricoil® coiled wire fabric systems for the Building 4 parking garage on the HCA Campus in Nashville, Tennessee. The company is a leading manufacturer of coiled wire fabrics for a wide variety of applications. The Fabricoil® product meets all of the functional requirements—most notably ventilation, fall protection, and long life cycle.
Cascade Architectural
www.cascade-architectural.com
GRS Laminated Glass Railing System
The GRS Laminated Glass Railing System features advanced dry-glaze technology and a precision-torque installation tool that automatically levels and plums the glass panels for enhanced sightlines. The system is impact resistant and has Florida Product Approval. It is also ICC-ES certified, which takes the guesswork out of meeting building codes nationwide.
C.R. Laurence
www.crl-arch.com