Growing Green at Conservatory, Botanical Garden Welcome Center

by Tracy Ostroff
Associate Editor

Summary: IKM Architects’ Welcome Center at the Phipps Conservatory and Botanical Gardens in Pittsburgh opened last year, providing for city residents and visitors a grand new entry to the beloved Lord and Burnham Victorian greenhouse, originally erected in 1893. Key to their design are the many sustainable features that resulted in a Silver LEED® rating, and that realize the mission of industrialist Henry Phipps, who founded the conservatory to teach and inspire visitors while bolstering their mental and physical health. The architects and conservatory officials call Phipps the most “energy-efficient conservatory in the world.”

Because of the conservatory’s historic designation, any changes to the structure required layers of approval from city planning and zoning regulatory boards as well as federal agency appraisal. The design solution was a win-win for reviewers and the environment: the Welcome Center is set into the earth, where its scale, massing, curvature, and form pay homage to and keep the views of the Lord and Burnham conservatory. At the same time, its siting boosts energy efficiency.

The historically sensitive design and palette is sympathetic to its Victorian neighbor, says Joel Bernard, AIA, principal/project manager. But, he says, “There is no mistaking its Modern sensibility.” A pair of limestone winding staircases envelops the courtyard and leads up to the upper walkway. The welcome center entrance sits between the two staircases, which Executive Director Richard Piacentini has called, “the most attractive entrance to a botanical garden in the entire country.” Inside, visitors reach the Palm Court and conservatory exhibits via the grand stairway or elevator.

From the top of the conservatory
The architects and Phipps officials say the welcome center design is saving up to 40 percent in energy costs, 22 percent above the required level for Silver-LEED certification.

The architects had to determine how to draw light into the below-grade welcome center. Their solution lay in a fritted-glass dome above a central atrium that permits daylight to enter the lobby, gift shop, and café, reducing the need for artificial lighting. A wall of laminated, insulated windows runs the length of the concave courtyard and controls glare and heat. Low- or no-VOC paints complement the sustainable products. To increase passive energy savings, the glass dome is vented to help cool the building. Air conditioning is only required below grade level. A green roof surrounding the glass dome provides a heat sink to enhance the building’s efficient climate control system.

To the bottom of the entrance
Steam heat warms the conservatory. It’s great for the plants, Bernard says, and is also reused in a unique way. Otherwise, wasted steam condensate warms the sidewalks through a network of heating pipes under the walkways as it returns to the steam plant shared by neighboring institutions. A computer program is connected to a weather station that triggers the heated sidewalks as freezing precipitation is detected in the atmosphere. Bernard says the snowmelt system reduces the use of fossil-fueled snowplows and environmentally unsafe de-icing chemicals.

The front lawn is planted with a drought-resistant turf; Phipps will eventually collect rainwater too from off the dome.

The $5 million welcome center features an 11,000-square-foot reception area, including a café, gift shop, and art gallery. Piacentini says the strategies for the architecture and inside amenities are “compatible with the way we feel we should be running our operation.” The café features locally grown and organic foods, corn-based “plastic cups,” and biodegradable recycled paper products. Piacentini says Phipps is the first conservatory to use an anaerobic organic waste digester to compost pre-and post-consumer café waste. In addition, the gift shop offers fair trade items.

Flexibility and tweaking
Both architect and client appreciate the flexibility the other party exhibited, along with partner Turner Construction, to tweak the design and to “never say never” Piacentini says. For example, the snowmelt system was not included in the original designs; it was added once the team learned that they could return water to the central steam plant at any temperature—it did not have to be cool water.

The architects and the conservatory worked together to achieve model design and technology applications. The new Tropical Forest Conservatory continues to develop Phipps’ sustainable features, with the anticipatory computer-controlled weather and temperature reacting system, fuel cells to produce energy from natural gas, symbiotic heating systems, energy blankets to prevent heat loss and capture heat gain, and a computer-controlled Venturi effect with a passive system to suck hot air out of the conservatory.