The iconic U.S. Bank Tower, designed by Pei Cobb Freed & Partners and completed in 1989, stands at 1,018 feet tall, long the tallest building in the city of Los Angeles, state of California, and east of the Mississippi (it was only recently surpassed by the new Wilshire Grand Center in 2016). Recognized for both its height and its glowing top-level crown – lit different colors to coincide with holidays and special events – the U.S. Bank Tower now has a new highlight. 71Above restaurant debuted in July 2016 with 360-degree views from its vantage point on the 71st floor. Diners can reserve specific locations in the round dining room, to capture views from the Hollywood sign to the harbor.
But how to ensure those views are always perfect – and diners’ experiences aren’t compromised by solar glare or excessive heat transfer? Giroux Glass, a leading Southern California facade contractor, worked closely with the design team to develop an effective solution. Electrochromic glass can be programmed to tint, control sunlight, and manage heat gain through subtle color changes. Giroux went on to provide project management, coordination, procurement and installation services.
Also called dynamic glass, electrochromic glazing eliminates the need for internal or external shading devices or glare protection. In addition to improving occupant comfort and reducing cooling loads, dynamic glass offers UV protection for interior fabrics and finishes. The electrochromic industry expects to achieve $4 billion in market share by 2023, according to SageGlass, a wholly owned subsidiary of Saint Gobain and a world leader in energy efficient window glass.
A total of 192 units of SageGlass’s eponymous triple-pane glazing were installed at 71Above. The dynamic system operates via programmable software controlled by restaurant management. Up to three tint zones in each pane of glass enable customized light settings that track the sun’s trajectory and can be adjusted for season or time of day. A mobile control app complements traditional wall controls, affording flexibility to change the glass settings from anywhere at any time. In addition to affording diners clear views, the windows reduce HVAC demand by blocking up to 91 percent of the solar heat.
According to the SageGlass website, “It takes less electricity to operate 2,000 square feet of SageGlass than it does to power a single 60-watt light bulb.”
Giroux Glass Director of High-End Design, Brad Leslie explained that the installation of electrochromic glass required many considerations. Space needed to be planned to include the hardware and software necessary to operate the windows. “Factoring in the installation of technology is becoming an important part of our process,” Leslie said. The Giroux team is experienced with advanced glazing technology and frequently works with dynamic glass applications.
Giroux’s union-certified glaziers were comfortable with both the project’s technology and working at the extreme height, even in the dense urban environment of downtown LA. The company serviced the U.S. Bank Tower on several past projects and worked on LA’s next tallest skyscraper, the AON Building.
According to Giroux superintendent Alan Shook, “The biggest challenges were wind and weather. At over 1,000 feet, the conditions are very different from way down at street level.” High winds caused swing-stage operations to shut down for a few days of the three-month installation, but predicted El Niño rains never happened, and Giroux managed to complete the work ahead of schedule.
Due to size constraints in the SageGlass manufacturing process, the windows could not be made as single lites. Instead, the Giroux team designed an additional horizontal band of glazing to match the existing lower window section. The center lites of each window measure 21-by-120 inches. These are flanked by lites of 34-by-100 inches. The upper band of windows includes center lites of 21-by-35 inches flanked by lites of 34-by-33 inches.
The windows at 71Above add another element to diners’ sensory experience. Operable tableside vents can be slid open or closed by guests who want to feel the 1,000-foot breeze.
All photos © AGW Communications
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