The second in our series of green infrastructure tours. This time Sonja O'Claire joined the ASCE SF Chapter's Sustainability Committee on a tour of the California Academy of Sciences ("The Academy"). Known as the "greenest musuem in the world," The Academy is an exhibit in-and-of itself for all things related to sustainable design. Tour attendees went behind-the-scenes to learn about the unique design elements The Academy employs to lower its impact on its environment.
Originally founded in 1853, the California Academy of Sciences was the first scientific academy west of the Atlantic seaboard. After rebuilding from the 1906 earthquake and fire, The Academy grew and expanded building-by-building through the decades, with little regard to cohesive design.
Aerial photo of historic California Academy of Sciences. Source: California Academy of Science
Suffering major structural damage in 1989, from the second large earthquake in its history, The Academy took the opportunity to completely redesign the building for the 21st century. However, The Academy didn't just settle for a new, more efficient, cool looking building. Architect Renzo Piano was selected to design a building that was innovative in its design, but would also reflect the natural world and the environmental issues related to protecting it. And man , did he deliver!
Using a wealth of engineering techniques Piano was able to incorporate all of the following into the building's design:
- A Living Roof
- Historical Heritage
- Passive Climate Control
- Water conservation
- Natural Illumination
- Recycled materials
1. The Living Roof
The living roof is one of the many gems of The Academy, certainly its largest. The roof fully actualizes Piano's idea to "lift up a piece of the park and put a building underneath." With its 2.5 acres the roof provides one of the largest areas of habitat dedicated to California native flora and fauna in San Francisco.
Nothing but natives here!
It is also as functional as it is beautiful. Beyond the habitat it provides, this roof does some heavy lifting. It acts as an outdoor classroom and provides research space for The Academy and its staff. Researchers can utilize the grids made by the lava rock infiltration trenches to map out and control their experiments. The roof also provides space for The Academy's whale bone specimens to be cleaned by nature for later use in exhibits.
With a helping hand from nature these whale bones are being cleaned for a future display.
Summary details of California Academy of Science Living Roof (click to zoom). Source: SFGate
What is also amazing is the engineering behind the living roof's construction so that it can capture, treat and utilize every drop of water provided from the daily fog cover to winter rains. The green roof system is engineered to support life in only six inches of soil. So not just any soil could be used, a special growing media supports all of the flora in only six inches. Materials and systems had to be selected to mitigate the extra load from the soil, plants, and water on the structure and to prevent intrusion from plant roots and water. Click on the detailed diagram to the right for details.
Additionally, the perimeter of the 2.5 acre roof includes over 60,000 solar cells. Currently, it powers between 1-5% of The Academy's daily usage. The placement of these cells was also no accident. By placing them away from the immediate roof edge they provide shading for the building's interior and exterior spaces. Even better is that the system was designed for expansion! Should more efficient cells become available in the future, all the cells currently filled by frosted glass can be replaced with solar cells.
Solar cells surround the perimeter of the living roof, providing electricity and shade. Source: The Traveling Squid
2. Historical Heritage
When The Academy was being redesigned after the 1989 earthquake the institution was already 136 years old, and had played a large role in the city's development and heritage. In the new building's design they wanted to honor its heritage and the environment it grew in. Piano did this many times over in his design, but a very prominent display of his understanding of spactial context is in the shape of the roof itself. The seven rolling hills of the roof mimic and celebrate the seven hills of San Francisco.
Much like San Francsico, this roof is not flat
3. Passive Climate Control
The rolling hills of the roof were not just for aesthetics, but are the engine of the passive climate control for the entire building. The shape of the hills direct the cool sea breezes that golden gate park is known for into the building. The automated ventilation system controls the retractable piazza cover and operable windows located throughout the building to release heat and let cool air in. Most of the heating provided to the main floor of The Academy is supplied by sunlight, radiant heat lines in the concrete flooring, or the guests' own body heat. Mechanical HVAC units are reserved for use in the more sensitive areas of the building, such as climate controlled labs and storage areas. Through these methods The Academy uses 30 percent less energy than federal code requires.
Diagram of how the green roof, piazza and guests provide passive climate control (click to zoom). Source: California Academy of Sciences
4. Water Conservation
Water has always played a significant role in California's development. To conserve this precious resource The Academy employs multiple strategies both indoors and out. Through the use of water-less urinals, low-flow faucets, toilets and showerheads throughout the facility, The Academy uses 32% below the LEED's baseline for green buildings. The living roof conserves water through utilizing native plants that are more adapted to the amount of water the bay area climate naturally provides through rain and fog. Due to the thin amount of soil provided to the plants irrigation is still required at times, but it is limited. Irrigation is typically only provided as needed during prolonged droughts and times of extreme heat events. During the wetter months 100% of excess stormwater from the roof drains into an underground infiltration chamber, replenishing the ground water table as if The Academy were not there.
5. Natural Illumination
Natural light and outdoor views are available in 90% of regularly occupied spaces of The Academy. The large floor to ceiling windows and skylights provide natural lighting to the main visitor and staff work areas. Special high performance German glass helps to reduce solar heat gain and cooling loads, while providing superior clarity of view. The interior details were minimized as much as structurally possible and curves were utilized so that the light could travel unobstructed throughout the space.
6. Recycled Materials
During the deconstruction of the original Academy some of the design elements were saved and reused in the new Academy. The metal decorative features surrounding the swamp exhibit are over 100 years old and were restored and reused from the original structure. Wooden benches were constructed from on-site trees that were removed during construction. The concrete throughout the structure was made using 50% recycled industrial by-products, fly ash and slag. 95% of all the steel used was from recycled sources. In fact, 20% of the building materials were manufactured within 500 miles of The Academy.
Overlooking the swamp exhibit you can see multiple examples of recycled materials
The amount of detail and thought that went into designing and constructing the California Academy of Sciences to be the greenest museum in the world is impressive. Too impressive to tell you all of it in this blog post. We would highly recommend attending one of their tours during your own visit.
Next up in this blog series of green infrastructure tours - Holloway Green Street! Want to learn more or join the ASCE Sustainability Committee? Contact us!