Baltimore's National Aquarium will make its iconic glass pyramid bird safe

In keeping with its conservation mission, the National Aquarium in Baltimore has announced plans to make all of the glass in its buildings “bird safe.”

The institution is planning to replace all 684 panes in the glass pyramid that covers its Upland Tropical Rain Forest exhibit after several panes shattered, indicating the existing glass is reaching the end of its expected life span.

As part of the project, each new pane of glass will be etched with a frit pattern designed to prevent birds from flying into it. With a price tag of $7.75 million, this will be one of the largest and most costly renovations in the country involving bird-friendly glass.

Originally designed by CambridgeSeven to be a sculptural centerpiece for downtown Baltimore’s lake-like waterfront, the aquarium opened in August of 1981 on Inner Harbor Pier 3 and will mark its 40^th anniversary this summer.

A second major building called the Marine Mammal Pavilion, designed by GWWO Architects, opened in 1990 on Pier 4 and also has a rooftop pyramid. The Australia addition, by CambridgeSeven, opened on Pier 3 in 2005. An Animal Care and Rescue Center, by Design Collective, opened in 2018 several blocks from the waterfront campus.

Aquarium president and CEO John Racanelli said the aquarium already has made about 3,000 square feet of its glass bird safe, mostly near the main entrance and in its Australia: Wild Extremes exhibit. He said work on the pyramid, requiring 14,900 square feet of double-pane safety glass, marks the first time it will etch a pattern into the glass during fabrication rather than apply dot patterns to a glass surface already in place.

“We think the building can be a really good example of how you can make a glass structure bird-friendly and lose nothing in terms of vision or aesthetics,” he said.

The aquarium isn’t stopping with the rooftop pyramid.

“If you’re going to protect the birds, you have to protect all the glass,” Racanelli said. “The ultimate goal is for all the glass in this facility to be bird-safe. It’s going to take a while to get to that point.”

The glass replacement work atop the rain forest is scheduled to start in March of 2022 and be complete by summer or fall of next year. Funds are coming from a mix of public and private sources, including $7 million from the state of Maryland. The pyramid’s steel frame is still sound and won’t be replaced, just the glass. Design Collective is the architect for the project and Plano-Coudon Construction is the lead contractor.

Along with the bird-safe glass, the aquarium plans to illuminate the building by adding high-efficiency LED lighting that traces and accentuates the outline of the pyramid. A similar effect is on view at the Tennessee Aquarium, which was also designed by CambridgeSeven and has four glass pyramids on its roof. The lights in Baltimore will be blue, to match the blue LED wave on the south end of the Pier 3 building; orange for the Orioles and purple for the Ravens.

The recipient of a Progressive Architecture award in the 1970s, the National Aquarium was designed to take visitors on a metaphorical journey from the bottom of the ocean to the treetops of a South American rain forest, high above the pier. Containing more than 17,000 specimens representing 750 species, it draws 1.2 million visitors in a typical year.

Under the pyramid is an immersive exhibit where visitors can see tropical birds such as the Blue-Crowned Motmot; two-toed sloths; blue poison dart frogs, and golden lion tamarin monkeys, along with thousands of plants native to South America. The glass enclosure serves as a greenhouse that helps keep the exhibit hot and humid year-round.

Racanelli said the aquarium staff knew the glass in the pyramid would need to be replaced at some point, but the project gained new urgency when one pane shattered in 2019 and others followed. No people or animals have been injured. The aquarium has installed a ballistic cloth barrier to catch any other glass that might fall and otherwise protect visitors until repairs are complete, so the exhibit can remain open and people can go through safely.

Rather than remove all the glass at once, the aquarium plans to replace 8-to-12 panes a day and then close up the building every night so it can keep the plants and the animals in place. The motmots and other exotic birds won’t be able to fly out because of a “bird screen” that has always been in place to prevent birds from getting into the rafters.

Racanelli attributed the failure of the glass to its age. Over time, he said, “the pane of the glass expands and contracts, but when it expands too far, it exceeds the limits of the frame that it is in. Then, the stress of the expanded piece of glass, which used to have more flexibility in earlier years, becomes too much and the whole pane shatters at once.” Because the panes are safety glass, he said, the shattered windows either stay in the frame or rain down in tiny pieces.

Fabrication of the new glass is expected to begin later this year, so it will be ready for installation in 2022. A fabricator has not been named but Racanelli said the new panes, measuring 4’-by-4’, will be tempered safety glass that takes advantage of advances in glass technology over the past four decades. Among the improvements, he said, the new glass will be made to higher standards such as better “insulative properties” and is expected to last even longer than the existing glass. In addition, he said, the new panes won’t contain nickel, a transition metal that may have contributed to the failure of the existing glass.

According to the American Bird Conservancy, up to a billion birds die each year in the United States after hitting glass surfaces, either windows or entire walls. Certain jurisdictions, including New York City, now require that new buildings have bird-safe glass. Some architects have begun specializing in the design of bird-friendly buildings such as the Integrated Science Commons at Vassar College, by Richard Olcott/Ennead Architects.

“At treetop height, birds are much more inclined to fly into glass, especially our kind of glass, because they see a tree inside the glass and they think, I want to fly to that tree, and then they hit the glass,” he said. “Getting the lower levels of Australia and the entrance glass bird-safe was the first priority because it was where birds were more likely to hit the glass.”

The rooftop pyramid is less of a threat to birds because it’s higher, he added. “Being five stories up, it’s up above the zone that’s most dangerous. Still, we were very eager to make sure the new glass that we are installing is bird-safe.”

To make the aquarium’s glass bird-safe, the fabricator will acid-etch a frit pattern that will be visible to birds but won’t interfere with the views of visitors who are inside the building looking out over the harbor.

Racanelli said the aquarium consulted with Lights Out Baltimore, a local organization that responds to calls about bird strikes and advocates for bird-friendly glass, in planning the glass replacement. At the same time, the aquarium didn’t want to alter what visitors see in the rain forest exhibit.

“The experience will not change for the guest,” said Racanelli. “It’s a structural improvement, that we are going to spend almost $8 million in order to make it so the guest notices nothing different… This is the kind of invisible improvement you have to do in a major public facility like ours in order for it to remain at a world-class standard.”

Racanelli noted that the National Aquarium was one of the first institutions to combine a land-based exhibit with water-based exhibits. Since it opened in 1981, about 20 other zoos and aquariums in North America have put exhibits under glass, including the Tennessee Aquarium, the Shedd Aquarium and the National Zoo, and “every one of them was inspired by what was created here for the National Aquarium.”

Although Baltimore’s rain forest is one of the first cases in which an aquarium has needed to replace glass over an exhibit, other institutions likely will have the same issues, he warned. “Every single one of them will face this conundrum.”