The World’s Greenest Museum

In designing sustainability into the new California Academy of Sciences building in San Francisco, renowned architect Renzo Piano turned it into one of the museum’s most powerful educational exhibits.

Unlike most world-famous architectural landmarks that tower into the sky, San Francisco’s new California Academy of Sciences building, which will open to the public in September 2008, probably is not even visible from the air. Its living roof blends into the lushly green Golden Gate Park and looks very much like someone lifted up a piece of the park and put a building underneath.

That is exactly the effect that Italian architect Renzo Piano wanted. “The special thing about this building is its setting in the middle of Golden Gate Park,” he explains. The other thing that was special to Piano was the fact that it would house a natural history museum. “I’ve designed a number of art museums, but designing a natural history museum is different,” he says. “It’s more about discovery, wonder and exploration, more about a connection between the space of the museum and the environment you are in.”

Piano’s beliefs reflected those of the Academy. A San Francisco landmark for more than 155 years, the California Academy of Sciences is the only institution in the world to combine a museum, aquarium, planetarium, and world-class research and education programs for 11 fields of scientific study under one roof. Damages sustained during the earthquake of 1989 necessitated replacing the cluster of old Academy buildings in Golden Gate Park.

The Academy seized the opportunity to develop a structure that would match its mission. “Science is more influential and relevant to our daily lives than ever before, and natural history museums can and must deal head-on with the issues of the 21st century,” says Academy Executive Director Dr. Gregory Farrington. “Our goal is to create a new facility that will not only hold powerful exhibits but serve as one itself, inspiring visitors to conserve natural resources and help sustain the diversity of life on earth.”

In 2005, the Renzo Piano Building Workshop, in collaboration with local firm Stantec Architecture, was commissioned to come up with a 21st century eco-friendly design that unified the Academy’s original array of 12 buildings.

Piano approached the project as he does all others. “As an architect, the first thing you have to do when you have a new job is walk on the site and try to understand the geography and topography of the land,” he explains. “Places talk. They have a story to tell…If you listen, a lot of things come to you. This is fundamental to architecture: to be able to grab all those things, and take them in your hands to make the design…Having no preconceptions in a job is essential. If you have preconceptions, you impose your style on the project. Every time you have to solve problems with new materials and new techniques.”

Piano says he saw clearly that the building had to address a couple of problems. Because of its location in a park, “First, it couldn’t be too aggressive; that meant it shouldn’t be too tall.” However, he was told that the planetarium and proposed rainforest had to be 70-90 feet tall, and the aquarium had to rise 60 feet. “The idea came to me to make a flat roof, like a flying carpet, and in the places where you needed to put the planetarium and the rainforest, it could curve up and curve down. It makes it more organic, a bit like it’s growing.”

That immediately suggested a planted landscape growing on the contours of the roof. “The living roof is a fundamental piece of the building,” Piano says. “It is actually one of the exhibits in the museum.” Piano

envisioned steep undulations in the roofline rolling over the domed planetarium, rainforest and aquarium, echoing the topography of the building’s setting and evoking the interdependence of biological and earth systems.

Maintenance of the roof , however, was a concern. The plants growing on the 2.5 acre roof had to be self-sustaining, without needing artificial irrigation and extensive care. Academy botanists worked with a team of architects and living roof experts to identify native plants that were well adapted to the coastal climate and hospitable to native birds, butterflies, and beneficial insects. Nine hardy species-four perennials and five annual wildflowers-were chosen after extensive testing and grown off-site in flat, biodegradable trays before being interlocked in place on the roof. The plant-covered roof is more than just educational and beautiful. It is expected to provide excellent insulation, keeping interior temperatures about 10 degrees cooler than a standard roof and reducing low-frequency noise by 40 decibels. It will also absorb about 98% of all storm water, preventing up to 3.6 million gallons of runoff from carrying pollutants into the ecosystem each year.

Another benefit of this roofline is that the domes of the Academy’s planetarium, rainforest and aquarium slope at the center in excess of 60 degrees, guiding fresh, cool air into a vast central piazza and circulating hot, stale air out through high-point vents.

Computer modeling determined optimal locations for portal-like windows in the domes to maximize sunlight into the living rainforest and coral reef exhibits without overheating the rest of the building. The windows are designed to open and close automatically to allow natural ventilation. Photosensors in the lighting system will also dim artificial lights in response to daylight penetration, reducing the energy necessary to illuminate interior spaces.

Part of that energy will come from solar cells embedded in the glass canopy that surrounds the outer perimeter of the building. As with so many other features of Piano’s design, the solar cells are not hidden from view, but are made an integral part of the building’s aesthetics.

“The solar cells cast a shadow on the space beneath them so the light around the building is not flat,” says Piano. “[The light] actually vibrates. I like very much the idea that the solar cells take the energy from the sun and also project a shadow.”

This embodies Piano’s approach to architecture, which he says, “is not just about making walls, floors, and ceilings. Architecture is the art of making emotion. I think that the two most important emotions of the building are the sense of vibration of the light and the sense of continuity between outside and inside.”

Piano intended his design to create a feeling of transparency and connectedness between the building and the park through selection of materials and arrangement of space. He used glass extensively in the exterior walls, so visitors can look through the museum to the surrounding green space. Visitors enter through the piazza which has a glass ceiling revealing the sky above. To maintain an open, airy feel, even the central support columns were made extremely slender through the construction of a fascinating “spider web” of carefully configured cables designed to prevent the slim columns from bending.

“Museums are not usually transparent,” says Piano. “They are opaque, they are closed. They are like a kingdom of darkness and you are trapped inside. You don’t see where you are, but here we are in the middle of a beautiful park, so you want to look out.”

Some of the building’s most sustainable features are not visible to the public. The structural framework is made from recycled steel. The insulation for the building is made from shredded blue jeans-an appropriate choice for San Francisco, which is the home of Levi Strauss, the company that made the world’s first blue jeans for California gold rush miners in 1853. In addition, the building’s proximity to the Pacific Ocean, a few miles away, will enable the Academy to pipe in ocean water directly and cycle it through natural filtration systems for the Steinhart Aquarium’s salt water tanks.

Although the new Academy building will not open to the public until this fall, it is being hailed for its sustainable design. It will become the first museum to earn a LEEDTM (Leadership in Energy and Environmental Design) Platinum certification from the U.S. Green Building Council. It has already received the 2005 silver Holcim Award for Sustainable Construction and the 2006 Environmental Award for sustainable design from the Environmental Protection Agency.

The awards validate the Academy’s and Piano’s objectives from the start. “A natural history museum is not just the place where you show science,” Piano says. “It is also the place where you discover science. When you study science, you realize that the earth is fragile. So this building has to be one of the most sustainable buildings in the world.”