(This article was originally published on www.FLSustainability.com)
Presenting a solution to the need in Florida for alternative building products as factors to sustainability is Fairview Architectural, manufacturer of innovative cladding panels. For decades, massive quantities of concrete have been used by the building industry in Florida. Offsetting the use of conventional types of concrete can be achieved by using alternatives that exemplify dematerialization, the concept of using less material to fulfill an intended purpose, as in cladding a building. This correlates with less embodied resources, lighter weight load, and in most cases, cost savings. Vitrabond® FR (fire-retardant) and VitrabondG2® (non-combustible) by Fairview Architectural are 4mm (0.157 inch) aluminum composite panels that use much less aluminum than conventional 1/8” aluminum plate, thereby having the advantages of aluminum but in significantly lower quantity.
Exceeding Hurricane Standards
Fairview Architectural North America has Florida Product Approval for HVHZ (High–Velocity Hurricane Zones) use of Vitrabond® FR and/or VitrabondG2® as integrated with their Arrowhead® attachment system1. Florida Product Approval is required in compliance with the Florida Building Code for using products as building envelope components anywhere in the state, and the HVHZ is defined as Broward and Miami-Dade Counties. The Florida Building Code is increasingly stringent, with an updated edition every three years. Products are evaluated according to test protocols depending on their intended application2.
The Arrowhead® system, collectively with Fairview Architectural’s aluminum composite panels, is efficiently used in exterior wall assemblies consisting of 1/2” fiberglass mat gypsum sheathing over light gauge steel framing. The system is referred to as a rainscreen, which is double layered construction separated by an airspace gap. The exposed outer layer blocks nearly all of the wind-driven rain, and shades the back-up layer, a continuous air/water barrier membrane applied directly over the sheathing, from exposure and the weathering effects of direct sunlight. In principle, though the rainscreen cladding is an open joint system, it is pressure-equalized so that moisture is not driven inward, and self-ventilating to allow escape of incidental moisture3. The patented Arrowhead® system is designed to simplify installation, minimize fallibilities, and reduce labor costs4. The system consists of small, intricately shaped linear profiles, which in this context can be referred to as pieces. First a base piece is fastened through shims to the back-up wall. An intermediate piece, to which the Vitrabond® panels are attached, interlocks to the base piece by an innovative T-clip5. The Arrowhead® system is non-sequential, meaning respective panels are installed independently of adjacent panels, thereby allowing flexibility in the construction process.
Passive Cooling Effect
Much of Florida has a unique near-tropical climate where cooling is the objective practically year-round. There are two different types of passive cooling strategies: thermal mass, and radiant barrier. When sunlight encounters a material, it is either absorbed, reflected, or transmitted. That which is absorbed is stored according to that material’s heat capacity and emitted according to its emissivity. Radiant barriers consist of a material, thin as it may be, that is reflective and has a low emissivity surface adjacent to an airspace5. The Arrowhead® system, collectively with Fairview Architectural’s aluminum composite panels, effectively functions as a radiant barrier. Solar reflectance varies depending on the color and gloss of the PVDF exterior finish.
Vitrabond® panels have a polyvinylidene fluoride (PVDF) exterior finish meeting AAMA 2605 performance standards7, providing an exceedingly high level of durability8, and resistance to dirt accumulation because of its fluoropolymer formula3. Fairview Architectural has extensive options regarding the aesthetics of PVDF finishes, and offers architects the opportunity for coordinating custom finishes. The variability of formulations allows for a wide range of colors, gloss, and special effects such as metallic speckling8. Specific formulations are proprietary, but constituents such as metal oxides and mica pearlescent are used for aesthetics8. The finish is factory-applied by coil coating6, a highly automated and highly efficient process. On a continuous coil coating line, the aluminum sheet is uncoiled, pretreated, primed, coated, cured in a finish oven, then recoiled. The continuous coil process minimizes liquid paint waste with nearly a 100% transfer efficiency, and also accommodates controlled collection of volatile organic compounds (VOCs)9. The exterior finish coating is extremely resistant to adverse conditions, including salt spray in coastal environments8.
Coordination and Subcontracting
The decision to use these products should be deliberated early on in the planning stages to be integral to the overall design. Moreover, the supply chain consists of Fairview Architectural as manufacturer and a separate, typically local entity as fabricator. Fabrication of panels ready to mount on the wall assembly involves cutting to size, then routing and folding at the perimeter edge to result in a continuous return for attachment of respective panels. In Florida, the rep firm for Fairview Architectural is Building Envelope Associates. They provide consulting, design assistance, engineering support, and liaison with local fabricators and installers.