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ENERGY MANAGEMENT: Window Shopping in downtown Pittsburgh

Lazarus is the first freestanding department store built in downtown Pittsburgh in more than 25 years. The 247,000 sq. ft., four level retail space was a joint venture between the Pittsburgh Economic & Industrial Authority and Federated Stores. Designed by Cooper Carry Inc., an Atlanta-based architectural firm, and built by New York-based Turner Construction Co. in less than a year, the project contributes to the revitalization of downtown Pittsburgh while setting energy conservation standards for the entire city.

According to its creators, Lazarus Fifth Avenue successfully incorporates energy efficiency with the development's three main design points.

"First, connecting the store to street activity and achieving clarity of vision from the street into the building were very important. With the much higher light levels outside, the glass needed a high transmission factor for the visible light spectrum. Second, we needed a high-performance glass that allowed for comfort inside the store and was efficient for heating and cooling. Third, the glass needed a low transmission factor for the infrared light spectrum to prevent fading of fabrics and carpet," says Michael Lowry, AIA, senior associate and project manager with Cooper Carry.

The glass chosen for the job was Viracon VE 1-2M, an insulated glass unit with both inboard and outboard lights of clear glass, and a Solarscreen 2000 Low-E coating on the second surface. "While reflective glass would have provided higher thermal performance, there would have been no views into the store. Tinted glass has similar characteristics to the glass we used, but the color would affect perception of the color of the merchandise. While there are other glass units exceeding the performance characteristics, none has the unique qualities that allowed us to achieve our design aesthetic without sacrificing performance," adds Lowry.

The store sits atop a three level underground parking garage, with the corner entry located on a pedestrian retail mall at 5th and Wood Streets. "The city planners hope to reenergize downtown with two anchor stores at either end of the mall, as part of a long range revitalization plan," says Muse.

A package of design standards, including an energy program, enables Lazarus' parent company, Federated Department Stores Inc., to control and monitor all stores from its Cincinnati headquarters, from a high performance exterior building skin to in-house lighting design.

According to Lowry, the building design features include the following:

* Air conditioning is on variable- speed drive, and generally operates on a cooling speed to offset heat loads from lighting.

* Exterior walls consist of precast concrete with insulation.

* Roofing is a modified bitumen system with more insulation than codes require.

* The cast-in-place, post-tension precast concrete and steel structural system integrates the underground garage and building with 30 foot by 30 foot bays, and a grid shifted 15 feet to allow additional parking on one end. A flat concrete slab maintained shallow floor heights of 9 feet 4 inches in the garage.

To maintain an open feeling often found on main levels of older stores, the first floor is 20 feet high, while other floors are 18 feet high.

* Stone is used at the base of the building, where pedestrians can see it, while precast concrete and stainless steel is used above street level, for durability and elegance. Stainless steel canopies over entries and show windows extend over the 12 foot sidewalk, suggesting an outdoor ceiling space.

* Exterior lighting includes indirect uplighting and direct downlighting fixtures, attached to the building.

Demolition for the Lazarus project began in June 1997, and construction was fast-tracked to allow occupancy within a year. "We coordinated over 40 subcontractors in a small, busy space. The store extends to the sidewalk, so the only staging areas were right along the sides of the building. In an urban site, there is limited room to work. We set strict limitations on what could be brought onto the site and organized the project in phases," says Jeff Turconi, Turner's Pittsburgh-based project manager.

To achieve the integral glass and glazing aesthetic, the locally based glazing contractor, D-M Products Inc., worked closely with Wausau, Wis.-based Wausau Window and Wall System's engineering team throughout the design and installation phases. Along with engineering, fabricating and manufacturing the window and curtainwall system, Wausau formed the ornamental aluminum facades and column covers.

"We brought in Wausau early on to help with the engineering and detailing. We selected Superwall for its flexibility in profiles from floor-to floor, while keeping the same structural support throughout the building," says Dick Macurak of D-M Products.

To de-emphasize individual floors, the glazing transitions from vision glass to glass that is translucent but not opaque, an effect created by sandblasting the third surface of an insulated glass unit. In the evenings, dramatic interior lighting shines through the windows to create new energy along the adjoining streets and sidewalks of downtown Pittsburgh.

"The Superwall system provides superior thermal performance by keeping interior spaces warmer in cold climates, and cooler in warm climates through the use of insulating glass and a thermal barrier. Low emissivity offers tremendous energy efficiency without reducing the amount of natural light coming into the building," says Merle Glaser, regional sales manager for Wausau Window and Wall Systems.

The window system at Lazarus consists of an aluminum framing holding glass separated by a thermal break. Overall, the energy-efficient system consists of three elements: the thermal separation, insulated glass unit and the special glass coatings. "With the Superwall system, designers need not limit window size to let in natural light without jeopardizing energy efficiency," Glaser adds.

"Lazarus brings a contemporary sophistication to an established urban context. The use of glass plays a dominant role in the architectural design. It not only helps to define the corner entrances, but also allows pedestrians to look into the store," says Jerome Cooper, FAIA, chairman of Cooper Carry and design principal for the project.

"This building connects Lazarus with the rich heritage of the grand old department store. The visual transparency, both at street level and above, connects pedestrians with activity inside, reenergizing the street. The extensive use of glass and corner entrances, reinforcing traditional pedestrian circulation in urban settings, is a stark contrast to the typical suburban department store," Cooper concludes.

As an urban design success story, the Lazarus building illustrates how the right glazing choices can decrease energy costs while increasing downtown energy and economic benefits.

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