Meeting simultaneous design criteria in one product can be a challenge. However, a new glazing...
“This project demonstrates that buildings can be secure, sustainable, efficient and beautiful” says Carl Galioto, FAIA, Technical Partner, Skidmore Owings and Merrill LLP
Creating the first building at Ground Zero has been a significant challenge for SOM’s technical group. However, now that Seven World Trade Center (7-WTC) is officially open, it will offer many additional "firsts" in skyscraper design and achievement. This is also the first NYC skyscraper to receive a LEED-CS Gold rating. The 52-story building has floor-to-ceiling windows from the 10th story up. Viracon supplied all glass for the tower. It’s been dubbed by Lower Manhattan interest groups as the "world’s safest and greenest skyscraper."
According to Galioto, 7-WTC serves as a marker to the northern entrance of the WTC site, and is designed to appear like a crystal. Its floor-to-ceiling windows maximize natural light transmittance into interior spaces to minimize artificial illumination. This "daylighting" not only reduces energy consumption, but also improves quality of life for occupants. Correct glass specification was critical.
As Galioto says:”Our challenge was to create a very flat, mildly reflective, sharp, crisp object. There is a very delicate, subtle balance we need to achieve. We want to let in as much light as we can. We want some amount of reflection, visible light transmission and no glare in work spaces. Our glass choice needs to balance visible light transmission, exterior reflectance, solar heat gain, interior reflectance, interior glare and U-value…We believe the Viracon glass played a very important role in our LEED-CS Gold rating.”
Typical glass makeup included: 1 3/16" VRE15-59 Insulating Silkscreen – consisting of 3/8" low iron glass with Solarscreen VRE-59 coating on the #2 surface and a Custom Dot Silkscreen pattern with Viraspan V948 (medium gray) ceramic frit color on the #2 surface + ½" Stainless Steel Air Spacer (warm-edge technology) with Gray Silicone Sealant + 5/16" low iron glass.
Viracon’s Rick Voelker, Vice President of Technical Services, says this is the first skyscraper using VRE-59. It combines reduced solar heat gain and visible light transmission. The gray ceramic frit is dense at the top, phasing out by eye-level. This provides the least noticeable screen from the exterior and prevents interior glare, while bringing in more light.
Proof positive came during a March ceremony to celebrate their LEED-CS Gold certification. Galioto says people inside 7-WTC were comfortably reading and writing 30-40 ft. away from the building’s perimeter, without any overhead lights!
Galioto adds that the building’s lighting system also played an important role in achieving a LEED-CS Gold rating. Tenant spaces can be configured with sensors that automatically balance interior light levels with daylight levels. This also considerably reduces energy use, as interior lights consume a significant amount of energy.
Galioto is also pleased with Viracon’s glass product and assistance, adding, "Viracon can deliver top quality products in the quantities and in the time that our projects require."
Glass contractor for 7 WTC is Permasteelisa Cladding Technologies Ltd.
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