By Joshua Bowditch
Architecturally, the Gulf Coast Medical Center Expansion, described as the addition of fifth, sixth, and seventh floors, is unconventional and in many ways is exemplary of sustainability in southwest Florida. Sustainability can be defined as eco-friendly, efficient, and resourceful, and in regards to construction can be considered on the basis of building materials, specifically raw materials, supply chain, and characteristics of the end product. The basic components of building materials are geological resources which must be processed to some extent. This expansion is clad with a terracotta panel system by Avenere Cladding LLC, and high-performance glass units by Viracon framed by curtain wall system by Physical Security LLC. The structure was not damaged at all from Hurricane Ian, which is a testament to its sustainability.
The cladding system represents a different strategy for exterior wall assemblies known as rainscreen, which is layered construction1. The exposed outer layer blocks nearly all of the wind-driven rain, and shades the back-up layer from 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 moisture1. The terracotta paneling was manufactured in Weroth, Germany, by Tonality GmbH2. Raw materials are clays and chamottes (fire clays) from Germany’s Westerwald region2. These are batched in designated proportions and mixed with water into a malleable solid, and shaped into profiles by extrusion2. The extruded section is subjected to a drying process, and sintering at 2,200°F in a rolling oven to obtain technical characteristics2. The terracotta panels are naturally earthtone in color and are exceedingly smooth at the face. At the back, the panels are profiled to interlock with vertical aluminum supports. The vertical supports are fastened over horizontal aluminum brackets, known as Z-girts1, which are fastened to the actual wall composed of membranous waterproofing over Georgia-Pacific DenGlass® sheathing over metal framing. Distinct advantages are that the terracotta panels are thin (1” total thickness)3 and relatively lightweight (7.5 lb/sq ft)4, durable4 and resistant to weathering2, and reflective.
The high-performance glass units are 1-5/16” nominal thickness, comprised of three plies of 1/4” glass; specifically, one ply of 1/4” green glass with a VE-48 coating at the inward surface, plus 1/2” airspace, plus two plies of 1/4” clear glass with a laminate interlayer. VE-48 stands for Viracon low-E with a nominal light transmittance of 48%5. The term “low-E” refers to reduced emissivity of heat from the glass surface. The low-E technology utilized by Viracon is magnetic sputtering vacuum deposition (“MSVD”)6, which applies metal atoms onto the glass to form a microscopically thin coating with spectrally selective, infrared reflecting properties. This is significant considering the solar spectrum is approximately 51% infrared, 47% visible light, and 2% ultraviolet light5.
The RT-3 Series curtain wall by Physical Security LLC is a preglazed system, meaning the glass is sealed to its metal frame at the factory as opposed to on-site. With preglazed systems, the glazing (sealant) is applied and cured in a controlled environment, where there is no variation of temperature and humidity, and no exposure to airborne contaminants7. The sealant type used, Dow Corning 983, is specifically for structural glazing, and over that Dow Corning 795 is used as a weatherproofing seal. A specialized attachment to the curtain wall referred to as “terracotta fin” borders the edges of the terracotta cladding system by extending slightly beyond the face of the terracotta panels at the perimeter of curtain wall openings8. A thermal gasket provides a thermal break separating exterior metal components from load-bearing interior metal components8. The exterior aluminum finish is Duranar® Sunstorm® Arcadia Silver UC70123F8, which has a solar reflectance index of 599. Duranar is a fluoropolymer powder coat finish meeting AAMA 2605 performance standards9, which is the highest level of durability among exterior grade finishes for aluminum alloy extrusions10.
Aesthetically pleasing as the Gulf Coast Medical Center Expansion may be, these aspects described would be generally unknown. It is publications like this one that can provide representation of these sustainability aspects through description and illustration. That would be the intent of “Architectural Stewardship”.
Acknowledgements
Special thanks to Trevor Barrett of Physical Security LLC for specifics on the curtain wall system.
1Ehrlich, B. 2014. Cladding: More Than Just a Pretty Façade. Environmental Building News 23(9): 1-10.
2Tonality® Ceramic Facade Elements. 2019. Environmental Product Declaration. Tonality GmbH.
3Product Approval #22315.1 (NeaCera Terra-Cotta Wall Panel by Avenere Cladding LLC).
4NeaCera® Product Overview. 2020. Avenere Cladding LLC.
5Insulating Glass Specs & Tech. 2008. Viracon®.
6Architectural glass solutions from Viracon. 1997. Glass-Technology International (5): 308-314. Artech Publishing.
7Takish, M. S., M. H. Haugsby, C. M. Schmidt, and W. J. Schoenherr. 1989. Structural Silicone Sealant Curtain Walls: Field or Factory Glazing? In: Science and Technology of Glazing Systems, ASTM STP 1054, American Society for Testing and Materials, pages 58-65. C. J. Parise (ed.)
8Gulf Coast Medical Center Phase 2 Shop Drawing. 2018. MCY Engineering, Inc. Glazing Consultants.
9Architectural Liquid & Powder Coatings Color Guide. 2013. PPG Industries.
10Aluminum Extrusion Manual, 4th edition. 2014. Aluminum Extruders Council.
