Article taken from Pruned (an excellent Landscape Architecture blog)

Sidwell Friends School
(The wetland machine of Sidwell Friends School by Andropogon Associates, Kieran Timberlake Associates and Natural Systems International. Image by Andropogon Associates.)

Reading an ASLA interview of Jose Alminana, a principal at Andropogon Associates, we were reminded that Sidwell Friends School, the Quaker school of choice for the Obamas, the Clintons, the Gores, the Bidens, the Nixons — practically every member of Washington’s politocracy, except for the Carters, of course — has in the courtyard of a recently renovated building an artificial wetland.

Not merely an eco-ornament, it’s a machine that “manages all the wastewater generated by the building, as well as all the rain water that falls on the site.”

Sidwell Friends School
(View from top of the wetland terrace towards the new building extension. Photo by Andropogon Associates.)

Typically, wastewater is drained away via a complex network of tunnels that requires vast financial resources just for its maintenance, an infrastructure that’s undoubtedly deteriorating just as fast as tax revenues get siphoned off away from public works budgets to General Motors and Bank of America. Miles and miles away from its point of origin, the water then gets treated in an energy intensive process. But it still isn’t entirely clean afterwards. Thus, when discharged, it still poses a risk to bodies of water, contributing in many instances to elevated bacterial count and eutrophication.

At Sidwell, wastewater is treated on-site, somewhat off-the-grid and using comparatively minimal infrastructure. The treatment cycle begins inside the building in a tank filled with anaerobic bacteria. Among other things, these bacteria help break down solids. The effluent is then pumped outside to a trickle filter before continuing on by gravity to a series of tiered wetlands. To lessen the health risk of contact with students and to mitigate any odor problems, water flows through beneath layers of pea gravel; there’s no surface flow, in other words. This planting medium contains phytoremediating plants which, together with the microorganisms attached to their root hairs and to the gravel stones, extract contaminants from the water. After slowly trickling its way outside for about a couple of days or so, the water then re-enters the building and gets collected in storage tank ready for reuse in flushing toilets, among other uses for greywater.

Sidwell Friends School
(Site plan: 1. Existing Middle School; 2. Middle School addition with green roof; 3. Trickle filter with interpretive display; 4. Wetlands for wastewater treatment; 5. Rain garden; 6. Pond; 7. Outdoor classroom; 8. Butterfly meadow; 9. Woodland screen at neighborhood edge; 10. Playground. Image by Andropogon Associates.)

Just as with wastewater, managing urban stormwater typically involves massive infrastructure to dispose runoffs as efficiently and as quickly as possible. In addition to being a drain on municipal coffers, such a method is known to increase the probability and the intensity of a flood event during major storms, endangering human life and property. Moreover, since stormwater isn’t allowed to remain where it falls, (1) water doesn’t have enough time to infiltrate the soil and seep into waiting, possibly depleted groundwater aquifers, and (2) what may have been clean at first contact with the surface undoubtedly will not remain so as it moves through sidewalks, roads, parking lots and sewers before going on to pollute rivers, lakes and other sources of our drinking water.

Sidwell Friends School
(Two students on the border between the rain garden and the pond. Photo by Andropogon Associates.)

At Sidwell, we get a hint of an alternative system for stormwater management: hyperlocal, lo-fi, modular (i.e., implementations at multiple sites would be needed to bring about an appreciable effect on urban hydrology), soft and comparatively cheap.

Sidwell Friends School
(Section cut through the 1. tiered wetlands used for wastewater treatment; 2. rain garden; and 3. pond. Image by Andropogon Associates.)

Runoff is directed to a rain garden and a permanent biology pond located downslope from the tiered wetlands used for wastewater treatment.

Sidwell Friends School
(Flow diagram of stormwater runoff. Image by Andropogon Associates.)

Some of the runoff gets in an underground cistern. During dry weather, this storage tank provides water to the pond. During heavy rains, excess water flows from the pond into the rain garden, simulating the hydrological dynamics of a floodplain environment. Water seeps through the soil and gets naturally filtered.

Sidwell Friends School
(Flow diagram of stormwater runoff from pond to rain garden. Image by Andropogon Associates.)

Andropogon describes this project as a “working landscape” but we might prefer calling it an “event landscape,” wherein natural processes are co-opted into a cybernetic amalgam of landscape, architecture, geology, biology and institutional pedagogy. Rather than in the inaccessible subterranean voids and in scientific abstractions, this eco-machine is made to perform out in the open for the edification of the elite who, in their dirty, smelly, real-world engagement with the landscape, will hopefully turn into great stewards of the earth.


Mine Brook Road

Mine Brook Road

taken from

As the credit crunch makes it harder than ever to obtain financing from lenders, some real estate players say an environmentally friendly portfolio may offer builders an advantage in securing funds to develop new projects.

“In general, financing anything is really difficult, given the credit crunch,” said Robert Politzer, president of Greenstreet Construction Inc., a New York-based builder with a New Jersey office in Princeton. But given the growing popularity of green building, developers who do not have green projects are at a competitive disadvantage, he said. “It would be easier these days to interest a potential funding group, whether a bank or private equity, in building a state-of-the-art green building than a conventional building project.”

Because of the benefits of green building, such as energy efficiency and reduced operating and maintenance costs, “you’re going to see increased tenant demand,” said Jim Lutz, senior vice president of development at Liberty Property Trust, a Malvern, Pa.-based commercial real estate developer that recently completed its first LEED-certified New Jersey project in Mount Laurel. LEED, short for Leadership in Energy and Environmental Design, establishes criteria for the design, construction and operation of sustainable buildings under the U.S. Green Building Council.

Higher demand means higher occupancy rates at green buildings as compared to conventional buildings, so “a lender who’s concerned with making sure that the loan gets paid back is going to see it as a less-risky investment,” Lutz said.

But while a green component may help to attract interest from lenders, it ultimately does not determine whether a building gets funded, experts say. “It’s much more subtle, how building green influences financing,” said Michael Saltzman, a partner at Newwork, a Newark-based real estate development company. “It’s more of a secondary factor.”

Less than two months ago, Newwork closed on nearly $17 million in financing from PNC Bank for The Richardson Building Lofts, a 67-unit, 86,000-square-foot, LEED Silver-proposed apartment building on Columbia Street in Newark. The project, which is the conversion of a former jewelry factory, broke ground Oct. 22, and is expected to be available for occupancy by next summer, Saltzman said.

“If a deal came into us that had green attributes, we’d be excited to see it, and we’d consider those as part of the overall underwriting,” said Bill Lashbrook, senior vice president of real estate finance at the East Brunswick office of PNC Bank, which has held in-house discussions about developing a green financing program.

The bank noted in its internal documents that Newwork had applied for LEED certification for its project, though Lashbrook said “the deal stood on its own merits,” including the property’s location in Newark, where PNC is looking to invest, and the current strength of the rental market.

The challenge of arranging financing for a green project lies in assessing the value of the building, Lashbrook said. “In real estate development financing and construction financing, the target is always to create enough value in the project so that [the] owner has the ability, whether it’s through refinance or the sale of the project, to repay the bank,” he said. But “we haven’t seen these properties trade in the market, so we’re not really sure how the market has come to value them.”

Many lenders helping to fund green projects are betting when the real estate market rebounds, such properties will bounce back faster than other types of buildings, said Lindsay Napor, executive vice president of Ecological Development LLC, a New York-based real estate developer working on two green residential projects in New Jersey. “People think when the market comes back … there will be a bump in value in those properties,” she said. Ecological Development has secured $90 million in financing for green projects in New Jersey in the past two years, and is working on obtaining money for two others, Napor said.

Rather than seeking loans from banks, Ecological Development has worked with real estate funds; real estate investment trusts, or REITs; and private investors for financing. “Real estate funds and REITs are still fairly well-funded,” said Anthony Sblendorio, the firm’s chief executive officer. “There’s still a desire by funds and REITs to deploy that money.”

Hampshire Generational Fund, for example, has made an equity investment in Ecological Development’s 89-acre green luxury residential development on Mine Brook Road in the Basking Ridge section of Bernards. The project, slated to begin construction in the spring, will include 12 LEED-rated single-family homes, organic agriculture and manmade wetlands for a stormwater treatment system.

The equity stake marks the first time that Hampshire Cos., the Morristown-based real estate investment firm that administers the fund, has committed capital to a green project, according to principal Robert Schmitt. “We liked the green concept,” he said. “We think it’s where the future is going to be for development.”

Hampshire is paying for improvements and entitlements for the property from its equity capital, Schmitt said, but the costs for land acquisition and construction will be far more substantial, he said. “That definitely hinders our flexibility with the capital structure for this project,” Schmitt said. The firm most likely will fund those costs through lines of credit set up with lending institutions prior to the crunch, rather than seeking new financing, he said.

It is uncertain whether Hampshire, which committed to the project in February 2006, would have made a similar investment during the current credit crisis, Schmitt said. “It’d be a tougher deal to commit to today,” he said. Still, “going forward, we expect to increase the number of green buildings in our portfolios,” he said. “They are buildings that are growing in value, because they are buildings that tenants want to occupy.”

Whitney Water Purification Plant image courtesty of Inhabitat

Whitney Water Purification Plant image courtesty of Inhabitat

article taken from

by Jorge Chapa

One of our favorite projects mentioned in the AIA/COTE 2007 list of Top Ten Green Projects was perennial Inhabitat favorite Stephen Holl’s Whitney Water Treatment Plant located in New Haven, CT. This project is fantastic in many ways, but the real beauty of it lies in the fact that the 30,000 square feet water treatment facility is sitting under the largest green roof in the state of Connecticut.

The long stainless steel building shown on the images house the extensive operational facilities required for the plant as well as an exhibition lobby, laboratories, a lecture hall, and conference spaces which are used for the multiple education programs that run on the facility. The roof garden design, the largest in Connecticut, expanded the existing wetland area where the site was located.

The shape of the building serves multiple functions. Architecturally the building has been cladded in thin steel shingles. The shingles, due to the shape in which they have been warped, absorb and reflect the heat of the sun preventing the exposed facility from gaining too much heat. Furthermore, the inverse-raindrop shape of the building, as well as reminding us of, well, rain droplets, also helps in reducing the area exposed to the sun reducing the heat gain even further.

The thin profile for the building allows all regularly occupied areas to have easy access to daylight. Furthermore, domed skylights in the green roofs allow daylight to enter the water treatment plant. These domed skylights serve a secondary function, which is that of allowing the visitors to the public parklands to see the water treatment process occurring within in the facility. On the materials side, the stainless steel shingles of the facade are recyclable and reusable. The building also features recycled terrazzo tiles, cork tile flooring, low VOC paints and sealants.

And of course, the most important feature of this facility lies in the way that it handles water for the project as well as how it interprets the processes of the water treatment in the facility below. The project is divided into six areas analogous to what is happening below the surface in the treatment plant. Those domed skylights mentioned above? They sit right above the ozonation bubbling area of the plant. On an area where there is rapid mixing and high turbulence, little streams move along the grass above. Furthermore the facility’s landscape manages the storm water drainage system for the facility, preventing storm water runoff as much as possible.

Narrative taken from

Multiply Your Stimulus Dollars:
14x Stimulus
A Plan for State and Local Governments

With: ICLEI – Local Governments for Sustainability, RESNET, and Veterans Green Jobs
14x Stimulus Plan Download the 14x Stimulus Plan
Take Action to Implement 14x Stimulus in Your Community

What if there was a way for states, cities, and counties to leverage each $1 of federal stimulus money spent to generate $14 of private spending, create 14 times the number of jobs, reimburse the federal government $3, and get $1 back to boot? Well, there is a way, the ‘14x Stimulus’ plan.

The plan, which is being proposed by Architecture 2030 and its partners ICLEI – Local Governments for Sustainability, RESNET, and Veterans Green Jobs is a state/local version of Architecture 2030’s Two-Year, Nine-Million-Jobs Investment Plan. The effectiveness of the national plan in creating jobs and private spending has prompted these groups to propose a public/private partnership to strategically focus stimulus dollars that will enable a full-scale building industry revival while simultaneously addressing energy and greenhouse gas emissions reductions.

The Plan: How it Works
Based on the same principles as the national plan, the 14x Stimulus plan recommends using state and local stimulus money to create a local mortgage buy-down program that offers reduced mortgage interest rates contingent upon renovating or building to meet specific energy reduction targets. For existing homes, mortgage interest rates would be lowered by 1% if, with a minimum homeowner investment in efficiency upgrades and/or renewable energy systems, the home is renovated to meet a minimum HERS 70 (or equivalent1 rating. For new homes, interest rates would be lowered by ½% for achieving a HERS 70 rating and 1% for achieving a HERS 50 rating. Assuming the current U.S. average, 30-year, fixed mortgage interest rate is 5%, the mortgage buy-down program would work as follows:
Mortgage Interest Rates
To qualify for the lower interest rate, new homes need only meet or exceed the minimum HERS 70 or HERS 50 rating. For existing homes, the homeowner must meet both the minimum HERS 70 rating and invest a minimum amount in energy efficiency and/or renewable energy systems. The minimum amount required to be invested is double the cost of the buy-down and is dependent on the amount of the mortgage as illustrated in the following table:
14x Stimulus Plan for State and Local Governments
The Return on Investment: Everybody Wins
The seemingly odd pairing of interest rates and energy reduction targets turns out to be economically powerful, both creating an immediate demand for construction jobs and generating significant private spending. For example, if a homeowner wanted to refinance a $200,000, 6%, 30-year mortgage at a 4% interest rate, the home would need to be renovated to meet a HERS 70 rating (30% more efficient than that required by the latest energy codes), immediately creating jobs by putting construction teams back to work. To qualify for the program, the homeowner must invest a minimum of $16,000 in efficiency measures, thereby generating much-needed private spending. However, even with the cost of the efficiency upgrades added into the new mortgage, at the lower 4% interest rate, the homeowner would pay a minimum of $168 less each month. Add to that an additional savings on energy bills of approximately $60 and the homeowner would save $228 or more every month. In addition, homeowners can take advantage of the $1,500 federal energy efficiency improvement and 30% solar tax credits, as well as any local incentives that apply.

The plan also encourages new home buying with reduced mortgage interest rates of homes meeting a HERS 70 and HERS 50 rating. For each new home sold under this plan, $1 of stimulus money generates about $42 of private investment.

It is this ability to generate large amounts of private spending that so effectively leverages each stimulus dollar. As a result, the 14x Stimulus plan generates 14 times the amount of stimulus funding4 in private spending and 14 times the number of jobs that would have been created by the stimulus dollars alone.

For example, if a city or county invests $1 million of its stimulus dollars and $1 million in additional state stimulus matching funds ($2 million total), the plan would generate $28 million in local private spending and create 434 new jobs. The federal government would be paid back $6 million in new taxes, triple its investment, with an additional $2 million in new tax revenue going into city, county and state coffers. An incredible return on investment. The more money invested, the greater the return.

It is also likely that, with lower rates and increased savings, homeowners will take advantage of the construction team being on site to do additional renovations – fix a bathroom, add a bedroom, remodel a kitchen – spending even more. In this case, the return on investment would be even higher, making this strategy even more effective.

The Urgency: Seizing the Opportunity
The private building sector represents 93% of total U.S. building stock while the public building sector represents only 7%. The economic health of every U.S. industry is tied to the private building sector, especially housing. This includes everything from steel, insulation, caulking, mechanical and electrical equipment, solar systems, glass, wood, metals, tile, fabrics and paint to architecture, planning, design, engineering, banking, development manufacturing, construction, wholesale, retail and distribution. Simply put, if we do not stimulate building construction, specifically, renovation and home building, we will not revive the U.S. economy in any substantive and lasting way.

In order to capture the job-creation and private-spending potential of the private building sector, the new 14x Stimulus plan encourages households off the sidelines and into the renovation and home-buying market. However, there are many other benefits to the plan, including reduced risk of mortgage failure, increasing home values, more disposable income for homeowners, jobs to those who will pay federal taxes, a new market for material and product manufacturers, and dramatically reduced home energy consumption and greenhouse gas emissions. The result is that, with a single solution, we can address the economic crisis, move the country toward energy independence and begin to tackle climate change.

There are few opportunities that come along that allow us to address several major crises at once, but this is definitely one. We cannot afford to let this opportunity slip through our fingers.

Stata Center Underground Detention image courtesy of Judith Nitsch

Stata Center Underground Detention image courtesy of Judith Nitsch

Article taken from The Environment at MIT

MIT has constructed the Stata Center, a major research facility designed by Frank Gehry. The site of the Stata Center is urbanized, and is located at the site of former Building No. 20 (razed in 1999). Prior to the commencement of construction activities, site conditions directed stormwater from the site into storm drainage pipes that connected to the City of Cambridge’s combined drainage/ sanitary sewers located in Vassar and Main Streets. Ultimately, the water flowed to the MWRA treatment plant or, during heavy flows, into the Charles River itself. The Vassar/Main Street intersection is prone to flooding, especially during severe storm events.

MIT now mitigates stormwater runoff from the renovated site by an innovative, state-of-the art (for an urban area) stormwater control and treatment system. Approximately one half of the Stata Center site is drained to a “biofiltration” swale located between Buildings No. 57 and 56. The biofiltration swale is constructed with soils and vegetated with plant species designed to provide natural biofiltration. The plant species employed are capable of filtering oil and grease as well as suspended solids from stormwater. Runoff entering this swale filters through the vegetation and is detained below grade in a galley chamber.

Original system plans identified the galley chamber as a system of 3 interconnected 48-inch pipes, however, new technologies were adopted that perform the same task more efficiently. Rather than the 3 tube system, a high-density, recycled plastic, lattice work system (rainstor) was installed to contain runoff water.

The rainstor is capable of holding the same volume of water (50,000 gallons)as the pipe system but with a much smaller footprint. This resulted in less excavation required and less impact on surrounding infrastructure systems. Outflow from the galley chamber is discharged at a controlled and reduced rate of flow by an effluent stormwater pumping station via a force main into the Vassar Street storm drain line, which will connect to the new stormdrain being constructed beneath Massachusetts Avenue.

Based on hydrologic modeling, this process will yield a 50% or more reduction in the peak stormwater flow rate compared to pre-development levels, and will achieve improved Total Suspended Solids removal from the runoff as well. The system is designed to achieve an 80 percent reduction in Total Suspended Solids. Finally, as presently constructed, the stormwater collection system also serves as a rainwater harvester – collecting rainwater, storing it, and reusing it within the Stata building for flushingwater.  The collected rainwater supplements the potable city water for all toilet-flushing activities.  It is estimated that the Stata building will consume approximately 5,000 gallons per day for flushing water, suggesting that the stormwater collection/ rainwater harvesting system will yield a discharge to the Vassar Street storm drain line.

Sidwell Friends Middle School image courtesy KTA

Sidwell Friends Middle School image courtesy KTA

Article taken from

By Ethan Goffman

First daughters Malia and Sasha Obama may be part of a new generation of “sustainability natives.” The term refers to those “who think and do naturally” what their parents will always find a bit unusual, according to Rachel Gutter, senior manager of the school sector for the U.S. Green Building Council (USGBC). In January the Obama children enrolled in D.C.’s Sidwell Friends School, immersing themselves in cutting-edge green facilities.

In September 2006, Sidwell’s middle school was the first to receive a Platinum rating from the USGBC. The school wanted to integrate environmental stewardship into teaching and life, in keeping with Sidwell’s Quaker philosophy.

“Stewardship is a central principle for Quakers,” says Michael Saxenian, assistant head of school and CFO.

Environmental stewardship pervades every aspect of Sidwell’s middle school, which 10-year-old Malia attends. The windows are positioned to flood the building with natural light while cutting down glare, and to lower heating and air conditioning costs. Natural ventilation and chemical-free construction materials ensure fresh air. Other features include a constructed wetlands, a lush, living roof with glass solar chimneys, a biology pond, photovoltaic panels, and cork and bamboo furnishings. The building uses “55% to 60% less energy than a standard-code building” Saxenian says.

These innovative features allow teachers to “incorporate the school itself, and green features, into the curriculum,” explains Gutter. “We’ve made systems within the building visible throughout,” says Saxenian. And students can track the school’s energy use and carbon dioxide levels online.

Constructed wetlands on campus teach water cycling as they filter and return “black” water to the toilets and cooling system. “That is a really powerful teaching tool,” says Saxenian; “It turns the out-of-sight out-of-mind mentality around,” and stimulates discussion of the nutrient cycle. According to Gutter, the plans for the wetlands went through a “rigorous process with the D.C. City Council” to gain approval. “I think the idea of on-site waste treatment raised a few eyebrows at first,” she says.

The building stimulates students in many ways. An eighth-grade science project involving a species census led students to discover a dozen bee species, four of them never before found in the District of Columbia. Such biodiversity, explains Saxenian, was likely enhanced by the many native plantings on the school’s grounds. Students also grow herbs on the green roof that are then used in cafeteria food. And one student team built a model solar car patterned after the roof’s solar panels.

Sidwell’s lower school building, which 7-year-old Sasha attends, has many of the same features, and is expected to receive a Gold rating shortly. Sidwell did not seek a Platinum rating for the lower school on purpose. While planners thought of the first building as “an opportunity to make a big statement in the nation’s capital and help other schools move in the same direction,” the lower building has a different purpose, where “every choice is both environmentally and financially responsible,” explains Saxenian. “Along with stewardship, simplicity is a core Quaker value, one embodied in the lower school.

Stone walls reclaimed from a 19th century barn, wood cladding reclaimed from wine casks and a trickling filter that also serves as an interpretive kiosk describing the wastewater treatment process.

One recent Sidwell graduate, Ben Wessel, is currently an environmental leader at Middlebury College. Wessel reflects that attending Sidwell at the dawn of the green building age created “a palpable change in the entire student body.” Students “recognized that every part of life can be modified to have a very small footprint.”

Gutter hopes that these lessons will spread. “I firmly believe that the Obama girls attending Sidwell Friends will be the best thing that has ever happened to green schools in this country,” she says. Not because of the media coverage, but because the children will “communicate these real-life lessons in sustainability to their parents.”

Green features at Sidwell Friends School include a green roof (above), stone walls reclaimed from a 19th century barn, wood cladding reclaimed from wine casks and a trickling filter (left) that also serves as an interpretive kiosk describing the wastewater treatment process.

California Academy of Sciences by Peter Kaminski

California Academy of Sciences by Peter Kaminski

Article taken from

Verdant Laboratory: A multi-faceted institution sheltered by a undulating green roof takes a holistic approach to sustainable design

By Joann Gonchar, AIA

Sustainable buildings don’t always look green, but the California Academy of Sciences, in San Francisco’s Golden Gate Park, is one that does. Covering the 400,000-square-foot building, which replaces a complex damaged beyond repair by the 1989 Loma Prieta earthquake, is an undulating 2.5-acre living roof dotted with porthole-like skylights. This rolling landscape was conceived as a swath cut from the park and elevated 36 feet to the height of the old buildings, according to Renzo Piano, the Genoa, Italy-based architect of the academy’s new home.

California Academy of Sciences, San Francisco, California


Location: San Francisco, California (Along Sections Of Pacific Ocean And San Francisco Bay)

Gross Square Footage: 400,000 Ft2 (37,160 M2 )

Cost: $488 Million

Completed: September 2008

Annual Purchased Energy Use (Based On Simulation): 103 Kbtu/Ft2 (1,160 Mj/M2 ), 12% Reduction From Base Case

Annual Carbon Footprint (Predicted): 18 Lbs. CO2 /Ft2 (87 Kg CO2 /M2 )

Program: Museum, Planetarium, Aquarium, Laboratories, Collections Storage, Offices


Team Owner: California Academy Of Sciences

Architect And Interior Design: Renzo Piano Building Workshop In Collaboration With Stantec

Architect Of Record: Stantec Architecture

Landscape: Swa Landscape

Architecture Engineers: Arup (Structural, Mep, Environmental); Bello Associates, Sj Engineers (Associates); Rutherford & Chekene (Civil)

Commissioning Agent: Ctg Energetics

General Contractor: Webcor Builders

The green roof-designed to reduce stormwater runoff, provide insulation, and create habitat for birds and insects-is the most conspicuous manifestation of the academy’s mission “to explore, explain, and protect the natural world.” Or, as Greg Farrington, the museum and research institution’s executive director explains, the academy’s activities are focused on pressing questions such as “How did we get here?” and “How we are going to stay?”

However, the rolly polly planted roof is just one of a whole array of coordinated strategies that helped the $488-million building earn Platinum LEED certification soon after its opening in late September. For example, contractors recycled 90 percent of demolition debris from the old academy; much of the new building, including open office areas and the main exhibition space, is naturally ventilated; almost all of its public spaces have access to daylight and views; and, the structure is surrounded by a glass-and-steel trellis that incorporates 60,000 photovoltaic (PV) cells, expected to generate 220 kWh of electricity annually.

According to data provided by the project team and interpreted by GreenSource, the new building will use 12 percent less energy than one designed to comply with ASHRAE 90.1-1999. The number is lower than the roughly 30 percent savings shown in the project’s LEED documentation partly because it is based on projected energy use rather than on energy cost. But more significantly, it assumes no savings in plug and process loads. Such loads are significant at the Academy, where energy-intensive equipment is required to support features like an aquarium, a planetarium, a man-made rain forest, and research laboratories, and to maintain the temperature and humidity levels necessary for preserving a vast collection of scientific specimens.

This programmatic complexity is packed into an envelope that (except for its bulbous roof) is remarkably straightforward. The building’s main floor plan is a simple rectangle, defined by four poured-in-place concrete structures at each corner. One contains the gift shop and café, two are devoted to research and administrative areas, and one houses a recreated exhibit from the original building devoted to Africa’s ecosystem.

Separating the individual shoe-box-like structures is floor-to-ceiling low-iron glazing that opens the building to the park and a 36,000-square-foot cruciform-shaped exhibition area. The space has a central skylit and largely open-to-the-air “piazza” flanked by two 90-foot-diameter steel-framed spheres. One sphere is glass-clad and encloses a multi-level rain-forest exhibit, while the other is aluminum-clad and houses the planetarium.

These domed elements are responsible for the roof’s primary protrusions: They “push” the height of exhibition hall from 36 feet at its lowest point to 70 feet as the steel structure and the living roof above rise to accommodate them. The aquarium occupies the level below, with large open tanks extending up to the main floor and defining the edges of the piazza.

The planetarium and rain forest each deploy their own climate control strategies. The planetarium relies on displacement ventilation, with cool air supplied through floor grilles. The system is quieter than those that provide forced air from above and is more efficient since it conditions only the occupied space rather than the planetarium’s entire volume, explains Kang Kiang, AIA, a senior associate with Mark Cavagnero Associates and formerly project manager for the academy’s executive architect, Stantec (originally Gordon Chong Partners Architecture).

The environment inside the rain forest is kept appropriately warm and humid. Light necessary for the tropical plants to grow is provided through the circular skylights and by supplemental electrical lighting. Misting ensures that temperatures do not rise above the design criteria of 79 to 84 degrees with 50 to 70 percent humidity, and a stream of high-velocity air prevents condensation from forming on the inner pane of its terrarium-like enclosure.

For the open exhibit hall surrounding the spheres, engineers took advantage of San Francisco’s mild climate, developing a natural ventilation scheme. Fresh air enters the exhibit hall through high and low level openings in the glazed facades, and warm air is vented, via the stack effect, through the porthole-shaped operable skylights on the roof. But ensuring that air would evenly penetrate, without creating dead zones or overly breezy spots, was no easy feat, because of the hall’s plus-sign-shaped plan, the undulating roof, and the two spherical obstructions.

“The unusual shape meant we couldn’t rely on rules of thumb to develop the natural ventilation scheme,” says Karl Lyndon, project mechanical engineer and an associate director in the London office of Arup. The San Francisco office, where Lyndon was previously based, provided multiple services on the project, including LEED consulting and mechanical and structural engineering.

In order to better understand how to naturally ventilate the exhibit hall, engineers analyzed the space using computational fluid dynamics (CFD) starting with schematic design. They refined these analyses as the design progressed and validated the results against the performance of physical scale models that they subjected to wind tunnel tests. Sensors measured factors such as pressure on the facades, wind speed, and direction.

The tests not only focused on visitors’ thermal comfort, but also on ensuring that indoor air was free of contaminants. For example, one study helped the design team optimally locate exhaust from boilers and mechanically ventilated spaces to keep foul air out of the path of exhibit hall vents and a rooftop observation deck. A particular concern was the placement of the roof stack from the penguin exhibit. “Penguins have bad body odor,” says Lyndon.

Ultimately the design team used the data garnered from the CFD analysis and wind tunnel tests to create a control sequence for the building automation system (BAS). The BAS, which monitors interior conditions through a series of sensors, and exterior conditions via a roof-mounted weather station, directs operation of the windows and roof vents, and other building systems, such as a radiant floor that provides supplemental heating and cooling, external roller blinds for sun shading, and daylight dimming.

Designers emphasize that these systems are tightly integrated with each other. “The academy’s natural ventilation can’t be thought about in isolation,” says Kiang. Other features, like the geometry of the living roof, and the insulation it provides, also help make natural ventilation a viable interior climate control strategy, he points out.

The roof provides other performance benefits as well, including absorbing almost all of the rainwater that falls on it. On the rare occasions when the its saturation point is exceeded, runoff drains into an underground recharge chamber and slowly percolates into the surrounding soil, explains Reed Davis, a principal in the Sausalito, California office of SWA, the project’s landscape architect. Davis estimates that annually only two percent of the runoff will reach San Francisco’s often overloaded combined sewer and stormwater system.

SWA worked with the museum’s own botanists and ecologist Paul Kephart of Carmel Valley, California-based Rana Creek Living Architecture to select the roof’s plant material. They evaluated species on the basis of their capacity to attract birds and pollinating insects, and for their ability to thrive in shallow soil and bluff-like conditions. The group eventually settled on a scheme of sedum, self-heal, sea thrift, and beach strawberry.

Because Piano wanted an alternative to the typical plastic trays used in most modular green roof systems, Kephart developed the BioTray, a 17-inch-square biodegradable container for growing medium and plants made of natural latex and coconut coir-a rapidly renewable product derived from coconut husks.

The 50,000 trays arrived at the site pre-planted and were installed on the roof within a 24-foot grid of gabions. The rock-filled cages prevent the trays from sliding down the roof’s hills and provide an infrastructure for drainage and irrigation, as well as a walkway for maintenance workers, says Reed.

Such innovative solutions for the roof, and the building as a whole, would not have been possible without the involvement of a mutli-disciplinary team starting with the earliest design phases. “This project embraced the concept of integrated delivery long before the term was a buzz word, ” says Matt Rossi, project director for general contractor Webcor Builders, San Mateo, California.

Sometimes as many as 25 people, including the owner’s representatives, the architects, the contractor, and consultants were in the same room trying to resolve questions surrounding constructability, budget, and schedule, according to Jean Rogers, an Arup environmental engineer and principal. “The burden of solving such problems fell to the whole team.”

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