renzo piano's california academy of sciences

renzo piano’s california academy of sciences is among the largest museums of natural history in the world. the living roof’s 1.7 million native plants were specially chosen to flourish in golden gate park’s climate, and provide controlled natural ventilation. the california academy of science — or AOS — designed by renzo piano consists of two buildings, each with approximately 27.43 m high, free-standing glass domes that house the planetarium and the living rain forest. a glass-covered piazza covering 183 square meters and approximately 1,160 square meters of variable exhibition space lies in between. the now five-year-old facility dramatically increased its reach and impact, doubling from about 750,000 to 1.5 million visitors annually and nearly tripling the number of students it teaches through fieldtrips and after school programs from 62,000 to 175,000.

inaugurated on 27 september 2008, the structure is worthy of superlatives: not only was this natural history museum singled out according to the criteria of the U.S. green building council on october 7, 2008 as the most sustainable building of its kind, it is also a multi-faceted work of art that evokes the history and architecture of san francisco. for the building structure and shell, architect renzo piano used his knowledge of bionics, meaning the physical construction principles were derived from biology.

the soil’s moisture cools the inside of the museum significantly, thus avoiding the need for air-conditioning in the ground-floor public areas and the research offices along the facade

green roof

front view

close-up

windows

windows

the more typical black tar-and-asphalt building rooftop leads to a phenomenon called the ‘urban heat island’ effect. the endless swath of black rooftops and pavement trap heat, causing cities to be 6 to 10 degrees warmer than outlying greenbelt areas. one-sixth of all electricity consumed in the U.S. goes to cool buildings. the academy’s green rooftop keeps the building’s interior an average of 10 degrees cooler than a standard roof would. the plants also transform carbon dioxide into oxygen, capture rainwater, and reduce energy needs for heating and cooling.

window detail

the two main domes cover the planetarium and rain forest exhibitions. the domes are speckled with a pattern of skylights automated to open and close for ventilation. while inside the glass-covered ceiling and facade elements in the piazza provide visitors with a view into golden gate park, the outside of the building looks just like part of park from a bird’s eye view. this is due to the fact that a majority of the roof areas comprise a green roof covering about 10,118 square meters occupied by 1.7 million native plants. according to renzo piano, the CAOS is intended to integrate into the scenery of the park like a gentle rolling hill and to use its striking domes to invoke the feeling of the seven hills that san francisco is famous for.

detail

detail

plan

roof

the dependence on organic structures extends to the entire rolling roof structure made from curved steel beams with a span of up to 29 m, which carry the concrete roof

the development of the fully glass-covered piazza proved to be just as challenging. measuring approximately 22 x 30 meters, the gently curving roof is supported by a dual network of steel beams, bolted together by horizontal braces. the triangular glass surfaces each have an edge about 1.83 m long and follow the dimensions of the underlying steel frame structure, giving the structure the multi-faceted appearance of an insect eye. in relation to ensuring features such as natural ventilation and climate control, the development of the architecture featuring large-spans of glass surfaces posed one of the most difficult challenges for this earthquake-prone region.

interior view

the expansive, floor-to-ceiling walls of glass enable 90% of the building’s interior offices to use lighting from natural sources

the ecological and climate-controlling innovations are impressive. CAOS informs its visitors not only using the exhibits about nature, but also by setting the standard regarding natural and sustainable building. german firm D+H mechatronic AG from hamburg developed the corresponding window and facade systems, which were installed by gartner metallbau. the task was to ensure complete climate control and ventilation technology without using primary energy sources whenever possible. though the CAOS does have integrated floor heating and cooling systems, these are only used in exceptional cases. that became possible due to the intelligent use of natural air flow that appears due to different dimensions of the curved roof constructions, domes and facade elements. this is how gartner installed 720 ventilation drives on the frontal glass facade alone. these were developed by D+H specifically for hard-to-reach windows. the drives are connected to the building control center and thus react to all internal and external climate data. the 40 controllable round roof flaps provide natural ventilation and climate control on the two domes over the rain forest and the planetarium.

for cool weather, a system of matched opening angles now provide for continuous background ventilation of the CAOS building complex without unpleasant drafts. for warm weather, small and large ventilation angles combine to ensure that excess room heat is extracted as quickly as possible. high-lying ventilation flaps remain open at night and use the cool weather at night for cooling if it was hot on the previous day. in addition, the ventilation sequences are controlled by the room temperatures, humidity of the air and the wind conditions. If, for instance, the CO2 concentration reaches a critical value during high visitation periods, ventilation intensifies automatically. the windows close when it is raining, foggy or extremely windy. the result of the intelligent natural ventilation concepts also impressed the U.S. green building council this october, who awarded CAOS with LEED platinum, the highest possible accolade. the use of renewable energy through solar elements, the high potential for saving water and the use of recycled material were assessed alongside the approximately 34 percent savings in energy usage through natural ventilation systems, heat recovery and shade.

in short:

— 90% of all demolition materials were recycled
— 32,000 tons of sand from foundation excavation applied to dune restoration projects in san francisco
— 95% of all steel from recycled sources
— 15% fly ash (a recycled coal by-product), 35% slag in concrete
— 50% of lumber harvested from sustainable-yield forests
— 68% of insulation comes from recycled blue jeans
— 90% of office space will have natural light and ventilation
— 60,000 photovoltaic cells; 213,000 kilowatt-hours
— 30% less energy consumption than federal code requirement

project info:

client: california academy of sciences
design team —
renzo piano building workshop, architects in collaboration with stantec architecture (san francisco) m.carroll, o.de nooyer (partners in charge) with s.ishida (partner), b.terpeluk, j.mcneal, a.de flora, f.elmalipinar, a.guernier, d.hart, t.kjaer, j.lee, a.meine-jansen, a.ng, d.piano, w.piotraschke, j.sylvester; and c.bruce, l.burow, c.cooper, a.knapp, y.pages, z.rockett, v.tolu, a.walsh; i.corte, s.d’atri, g.langasco, m.ottonello (CAD operators); f.cappellini, s.rossi, a.malgeri, a.marazzi (models)
consultants —
ove arup & partners (engineering and sustainability); rutherford & chekene (civil engineering); swa group (landscaping); rana creek (living roof); PBS&J (aquarium life support systems); thinc design, cinnabar, visual-acuity (exhibits)
general contractor: webcor builders

the california academy of sciences is a leading scientific and cultural institution based in san francisco. it is home to an aquarium, planetarium, natural history museum and research and education programs, which engage people of all ages and backgrounds on two of the most important topics of our time: life and its sustainability. founded in 1853.