In the still-developing building and construction segment, composites adoption had been slow, but is beginning to pick up, spurred by some promising regulatory changes. Early successes in the residential fencing and decking segment followed in the mid-2000s (read more about it in “Wood-filled composites jump off the deck” under “Editor’s Picks.”).
Laudable efforts by the American Composites Manufacturers Assn. (ACMA, Arlington, Va.) to modify the International Building Code (IBC) and a growing awareness of composites’ environmental sustainability through lifecycle analysis tools had previously earned the composites industry only small gains in what architects call the “building envelope.” Exterior decorative elements, such as cornices and columns and window lineals, entry doors, skylights and light panels represented a beginning. But industry observers saw big opportunities for composites in wall panels, foundations, building cladding and roofing. In 2014, that door began to open, as architects responded to the International Code Council’s (ICC, Washington, D.C.) revised (2009) International Building Code, which now includes IBCChapter 26, “Plastic,” and Subsection 12, “Fiber-Reinforced Polymer.” At CAMX 2015, in Dallas TX, US, Marcio Sandri, VP and Managing Director glass reinforcements for Owens Corning Business Solutions (Toledo, OH, US) told attendees that the construction market would consume 1.45 million MT of glass-reinforced composites annually by 2018, 3.6% growth per year.
Unitized panel systems will help spur the increase. They’ve become a popular alternative to conventional, stick-built construction in building envelopes because they can be prefabricated, off site, under controlled factory conditions. They vastly simplify onsite installation, decreasing expensive jobsite labor and shortening construction schedules. In 2009, the IBC’s new Subsection 12 approved the use of fiber-reinforced polymer (FRP) composites for such systems. In 2014, Kreysler & Associates’ (American Canyon, CA, US) Fireshield 285 panel system made them practical in structures taller than 12m (four stories and taller) with an FRP system that could pass the required NFPA 285 fire-resistance certification, allowing it to be used on what is currently the largest FRP façade installation in the US: the San Francisco Museum of Modern Art (SFMOMA) expansion (see “Architectural composites: Rising to new challenges” under “Editor’s Picks”).
Although Fireshield 285 offered SFMOMA the least expensive solution — reportedly 20% less thansolutions using competing materials — and eliminated more than 450,000 kg of secondary steel structure, Kreysler’s FRP panels still required the use of a secondary aluminum panel-framing system, manufactured by renowned façade design/build company Enclos (Eagan, MN, US). Aluminum-framed curtainwalls, however, are coming under fire because highly conductive aluminum radiates summer heat into air-conditioned interiors and channels warmth out of heated interior spaces in cold weather, significantly increasing energy costs. In addition, aluminum is produced in an energy-intense process, and that affects a building’s overall LEED rating, a third-party certification that evaluates a building’s construction and operational sustainability. That prompted Kreysler, Enclos and architects Gensler Los Angeles (Los Angeles, CA, US) to task design teams at the Material Innovation Lab within California Polytechnic State University – San Luis Obispo (Cal Poly SLO, CA, US) with developing unitized panel systems that carry more of the substructural load (see “The building envelope: FRP unitized façades” under “Editor’s Pick”). The trend, since then, is to see composites meet aesthetic, thermal management and structural load demands placed on external building cladding.
A parallel trend, in both commercial and residential building construction, is to replace aluminum with composite members in window frame and lineal components. and replace the steel and aluminum reinforcements now inserted into existing large-dimension vinyl and PVC window components. One proponent of the latter is Covestro (formerly Bayer MaterialScience, Pittsburgh, PA, US), which has spearheaded ongoing development work by a handful of materials suppliers and window and door manufacturers that are capitalizing on a convergence of new window technology, changes in the International Building Code and the introduction of the US EPA’s Energy Star 6.0 rating system, a federal energy performance standard for window systems.
That new technology features glass-filled polyurethane, a key benefit of which is seven times more effective as a thermal insulator compared to aluminum, which translates to much less thermal loss. One partner, Deceuninck North America (Monroe, MI, US), launched a new window reinforcement system, INNERGY, incorporating pultruded glass-fiber-reinforced polyurethane window stiffeners for insertion into customer’s hollow, extruded vinyl window sashes and frame profiles. The stiffeners comprise 80% glass fiber and 20% polyurethane and replace conventional aluminum inserts. After the customary initial sluggish reception to a product launch, Deceuninck, a supplier of window component systems to window manufacturers, reports a robust pick-up in sales. In 2015, shipments of the window increased 40-50% over 2014 volumes,” and the company expects similar growth rates during the next several years. Covestro’s market manager Paul Platte 60% of commercial buildings in the US are three stories and shorter, according to data published by the US Department of Energy. Performance requirements (load, deflection, fire and smoke) for high-rise applications are also more stringent and costly. Accordingly, Platte says, the company expects the next phase in the market extension of polyurethane pultrusion technology to be in residential and low-rise commercial doors and window applications over the next two to three years. Large-scale high-rise applications are envisioned as three to five years down the road.
In 2014, a substitute for poured-concrete foundation walls, the residential standard for private homes in the US for more than 100 years, was introduced in patented Epitome composite foundation walls from Composite Panel Systems (CPS, Eagle River, WI, US), fabricated by Fiber-Tech Industries Inc. (Cadillac, MI, US), using fire-retardant Modar resin from Ashland Performance Materials (Dublin, Ohio). In 2015, structural 3m by 9m thermoplastic composite panels made by Axia Materials (Seoul, South Korea) were introduced for walls, floors and roof structures. Using powdered in-house-developed matrix systems, Axia achieves water-like viscosity upon heating, which it claims achieves excellent wet-out, including impregnation of the filaments in the fiber, all in a continuous laminating process. The resulting 3m-wide facesheet stock, complete with UV coating on one side, is cut, then laminated onto various core materials, also in a continuous process, to produce composite structural insulation panels (SIPs) which are lightweight, waterproof and UV-resistant, and reportedly suitable for construction of military shelters, modular housing and much more. The flat structural panels can be shipped in a container and then quickly assembled on site via adhesive bonding and/or structural composite connectors.