Thanks to Paul Woolford, AIA, IIDA, LEED AP BD+C, design director in HOK’s San Francisco office, for this post describing the vision for the San Francisco Museum at the Mint adaptive reuse project, which will be one of the country’s most environmentally innovative museums.
This once was a working metal factory that produced gold and silver bars and coins. There also was a public function where people exchanged gold or silver dust for coins and bars.
To organize the building program, we swept away all the unfortunate interventions that had altered the building since the federal government stopped using it as a mint in the 1930s. To understand how the renovated building should function, we looked back to how Alfred Mullett, the original architect, had organized the public and factory spaces.
We proposed a radiant heating and cooling system to either go under the historic floors or beneath a shallow floor floating above them. This system allowed us to only condition spaces that people occupy: the first seven feet.
We have started design development for the gallery prototypes. We are working with Lawrence Berkeley National Laboratory on the analysis and design of these gallery spaces, which will be naturally illuminated and ventilated.
With the exception of what is required to heat and cool water for the radiant system, the design uses almost no mechanical fans. The only electrical lighting system needed in daytime hours is for spotlighting specific exhibits.
Inspired by Biomimicry
When the city was founded in the 19th century, the San Francisco Bay’s edge and marshland area were just a few hundred feet from where the historic Old Mint building sits today. We suggested a design idea that incorporates lessons from the local biome while creating new ways to collect and store water.
To get the most from the site’s water resources, we found a long-covered cistern in the central courtyard that taps into a deep well fed by a spring.
Next, we organized a biomimicry design charrette and worked with a biologist to look at how native Bay Area plants, especially ferns and succulents, use the precipitation here. This includes the few months of rain we get in the winter as well as the year-round fog that blankets the area on most mornings.
We discovered that, to collect this water, many of the native plants are covered in countless tiny nodules. The surface of the nodules resembles a half-round bump. When water falls on a plain, flat surface like a sheet of glass, it immediately runs off. When water falls on a horizontal surface that has nodules, it coats the nodules. There is more area to capture water before it runs off.
Our design creates a glass canopy structure floating above the Old Mint’s existing open-air courtyard. The canopy ties the building together structurally, brings in daylight and preserves the historic courtyard facade that is currently crumbling.
This canopy captures rainwater and moisture from the fog with the use of a fritted system – a ceramic dot screen raised above the surface of the glass canopy. The frits modulate the daylight and glare and the surface provides 100 percent more area for moisture to collect. When it drains off the glass, the water is captured by cisterns sitting on the roof. The roof becomes a living museum exhibit that relates to the site’s wetland past.
HOK / Biomimicry 3.8 Genius of Biome report