GLASS CASE STUDY

Photo courtesy of Vitro Architectural Glass

Project: The Tower at PNC Plaza
Location: Pittsburgh, Pennsylvania
Owner: PNC Financial Corporation
Architect: Gensler - Pittsburgh and San Francisco
Glass Fabricator: J.E. Berkowitz, Pedricktown, New Jersey
Glazing Contractor: Permasteelisa Group, Windsor, Connecticut

The Project: PNC Financial Services Group has more newly constructed LEED (Leadership in Energy and Environmental Design)-certified green buildings than any company in the world. The Tower at PNC Plaza opened in 2015 and was planned to be one of the greenest office buildings ever built.

The Challenge: Reducing energy use, maximizing natural light, and optimizing occupant comfort were among the primary goals for The Tower at PNC Plaza with the goal of meeting or exceeding the requirements for LEED Platinum certification–the highest designation available from the U.S. Green Building Council.

The Solution: The 33-story high-rise appears on the surface to be a conventional glass-and-steel skyscraper, yet the sleekly polished exterior hides a second glass facade along with a rooftop solar chimney, to create a “breathing” building that uses fresh air and solar energy to naturally cool, heat and self-ventilate for much of the year.

The Double-Skin Facade: The Tower at PNC Plaza ventilates using a window system in which the interior and exterior curtain walls are separated by an air cavity that provides insulation and helps control the building’s interior temperature. During spring, summer and fall, warm fresh air enters the cavity through small, vertical windows on the exterior facade (which open and close automatically, depending on weather conditions) then passes through vents on the interior facade, rises and escapes through the solar chimney. In the winter, the operation is reversed. The solar chimney seals the air cavity, allowing fresh air to be trapped and warmed by the sun so that it can be circulated to help heat the building. The thickness of the two-layer facade provides supplemental insulation throughout the year, and on warm, sunny days, automated blinds deflect heat to further reduce heat load and glare.

The Solar Chimney: The solar chimney consists of two vertical shafts located at the core of the tower, topped by a thick slab of concrete that is painted black and covered with glass. The black paint absorbs heat and warms the concrete, which creates a stack effect at the top of the chimney. When the building automation system senses that conditions are optimized for natural ventilation, it opens the operable windows and vents on the interior and exterior facades so that air can enter the building, warm naturally, then rise and escape through the solar chimney. In natural ventilation mode, which is expected to occur up to 42 percent of the year, the building can operate without fan power or electricity. The net effect of the ventilation scheme is to continually introduce fresh air into the building while reducing temperature-related energy consumption by up to 50 percent compared to similar-sized buildings.

The Results: In striving to create the greenest office tower in the world, PNC, Gensler and their partners constructed a building that was designed to surpass LEED Platinum certification. In addition to the sophisticated double-skin facade The Tower at PNC Plaza operates highly efficient water-based heating (radiant) panels and cooling (chilled beam) systems for supplemental temperature control. Not only do these strategies enable The Tower at PNC Plaza to consume up to 50 percent less energy than benchmark buildings of its size, but the high-rise also bathes more than 90 percent of its workspace in natural light.

LOUVERS CASE STUDY

Photo courtesy of Airolite

Project: Johns Hopkins Medical Campus
Location: 600 N. Wolfe Street, Baltimore
Architect: Perkins & Will Chicago, Illinois
Installing Contractor: ISEC, Inc., Mid-Atlantic Region, Columbia, Md.

The Project: Johns Hopkins has been recognized for more than a century as a leader in patient care, medical research, and teaching. Today, the expansive Johns Hopkins Medical Campus in Baltimore includes the highly respected The Johns Hopkins Hospital, numerous research and educational buildings, plus several outpatient and medical specialty clinics. The beautiful 1.6 million-square-foot building, The Johns Hopkins Hospital features two connected 12-story towers, the Sheikh Zayed Tower for cardiovascular and critical care and the Charlotte R. Bloomberg Children’s Center which houses a children’s hospital. The building was designed to complement the look of existing medical campus buildings while making a strong statement about the long tradition and promising future of medicine that is practiced, taught, and explored at this prestigious institution.

The Louver Need: The clinical building consists of two towers, each 12 stories high, that join together at the eighth floor. Although no louvers are visible from the south-facing front entrance of the building, the sides and rear of the facility contain over 21,000 square feet of louvers. In total, over $1.5 million dollars’ worth of louvers were installed. Most of the louvers form a continuous sweeping span around the sixth floor. The sixth-floor louver wall periodically rises up into the seventh floor and gently draws one’s attention skyward toward the eighth floor where the twin towers come together.

The Design Solution: Storm class louvers, extruded aluminum stationary louvers, and extruded aluminum drainable louvers were painted with a custom color-match Kynar pearlescent pewter coating to match other aluminum materials in the building. The sleek, clean lines of the louver walls with concealed vertical mullions complement the building’s impressive modern look. Six-to-seven-inch louver blade depths add further interest to the building’s exterior design. In addition to looking great, the louvers designed for this building provide much needed intake air and exhaust ventilation while minimizing or preventing water penetration.

The Results: The building’s location on the East Coast makes it vulnerable to occasional hurricanes and high winds blowing in from the Atlantic Ocean. Water penetration was minimized at reasonable cost by using a combination of storm class, stationary and drainable louvers. The storm class louvers were used on parts of the building with the greatest exposure to severe wind and rain off the coast.