responsive Cloud Machine

christian werthmann & loMa architecture.landscape.urbanism

pink cloud is a “responsive weather Machine” that reacts to the daily encroachMent of the san francisco fog cliMate. The cloud was conceived as a memorial to honor Harvey Milk, a gay rights activist and first publicly known homosexual to serve on the city council of an American city, who was shot to death along with Mayor George Moscone in 1978 by a fellow councilman. In 2000 Christian Werthmann & LOMA won the competition for the Harvey Milk Memorial with a design that “challenges traditional concepts of memorialization”. An artificially generated cloud was proposed as an immaterial alternative “where stone or bronze was the default material to fight against the erosion of memory”. Hovering over the intersection of Market Street in the Castro, directly above six lanes of traffic and 50,000 cars per day, the Cloud is not only a weather event, but also a dreamscape that declares the cultural dynamism of the Castro, the gay neighborhood of San Francisco. The Cloud is produced with a fog machine, a common technology used in stage events. The fog is composed of a glycol-water mix that can vary in density. The mix is heated to about 200 – 300˚F (93.3 –148.9˚C) and converted into vapor. Upon contact with cool air the vapor goes through a condensation phase to form a dense fog that when sprayed can reach a distance of 40ft (12.2m). Werthmann & LOMA investigated a variety of “cloud making” techniques, such as the fabrication of large-scale rain clouds in arid zones, steam generation, and theatrical special effects such as dry ice, as well as pyrotechnics. Many of those technologies involved massive infrastructure and energy, with adverse effects such as rain, haze, or carbon dioxide. These ephemeral effects were also studied for their duration, dimensional coverage, scattering and dissipating behavior, particularly in response to the daily weather dynamics. The most effective technology turned out to be the common fog machine. The proposal calls for two or three 30ft (9.1m) high poles to be placed at each intersection corner. The fog machine sits in a sub-ground chamber and pumps the glycol-water mix up to a spray nozzle located at the tip of each pole. Activated in unison, the poles emit fog and form the Cloud. Pole-mounted light fixtures illuminate the Cloud in a variety of colors. always varying in forM due to the force of winds, the cloud is also intended as an interactive piece, controlled by visitors via a coin-operated device or via wireless cellular coMMunication.

Harvey Milk Memorial, San Francisco, California, USA

light system Integrated below the release valves. The light machine is using the combination of color and pattern with a motorized color wheel with 13 interchangeable colors and continuous scroll effect. A powerful 250W discharge lamp and a highly efficient reflector give a forceful beam of light.

underground vault Each pole is supported by equipment installed in a nearby underground vault. This easy accessible shaft contains the tank with the fluid, pump and the light control unit. central-steering-unit Programmed to filter information from individual weather sensors, the steering and lightsystem sending a condition signal to the City department.

central-control-unit Managing incoming information and errorhandling. The control unit is turning the fogmachines off/on and gives commands to the light unit according to preprogrammed scenarios. weather sensor Constantly changing wheather conditions including air pressure, temperature and wind are registered and transfered by the weather sensor timing the appearance of the cloud above the crossing.

city department Wireless “on the road” contact to the steering and the central control unit.

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■ 1 the fog machine sits in a sub-ground chamber and pumps the glycol-water mix up to a spray nozzle located at the tip of each pole. six 30ft (9.1m) high poles are to be placed at each intersection corner. 2 pink cloud is not only a weather event, but also a dreamscape that declares the cultural dynamism of the castro, the gay neighborhood of san francisco. 3 elevation of pink cloud monument.

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