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Posts Tagged ‘Fabrication’

BY MEG CALKINS, FASLA

The stone industry adopts a new sustainability standard.

FROM THE FEBRUARY 2018 ISSUE OF LANDSCAPE ARCHITECTURE MAGAZINE.

In 14 Patterns of Biophilic Design, Bill Browning, an environmental designer and founder of Terrapin Bright Green, cites “material connection with nature” as a significant principle. In other words, materials from nature, with minimal processing, can be used to construct the built environment—reflecting the local geology and connecting people to a place and natural setting. More than any other material, stone fulfills this “pattern”—often seamlessly settling a built landscape into the larger natural context. Yet in some cases, heavy stone can travel thousands of miles between harvest and use—offering absolutely no connection to the local natural landscape and creating a substantial environmental footprint.

Stone holds great potential to be a highly sustainable construction material for use in paving, stairs, and walls. It can be extremely durable, with relatively low embodied energy (energy used to produce a material), and nontoxic. However, a study from the University of Tennessee estimates that more than half of all dimension stone—defined as any stone that has been cut or shaped for use in construction—is imported, primarily from China, India, and Brazil, owing to far lower labor costs and fewer worker safety regulations, which combine for a lower product cost. Some of this stone might have been harvested in the United States, sent overseas for processing, then returned as “imported stone.” Minimal records of stone harvest, sales, and processing make it challenging to track stone’s path to market. Additionally, environmental impacts from waste and water use in stone quarrying and manufacture are not insignificant. Fortunately, a new standard from the Natural Stone Council (NSC) and the American National Standards Institute (ANSI) offers criteria for reducing the environmental impacts of stone harvest and processing and requires a chain of custody for stone so consumers can know for sure the path their “local” stone has traveled.

The stone quarrying process is often lumped together with metal mining’s heavy blasting and toxic runoff, but Kathy Spanier, the marketing director at Coldspring in Minnesota and a participant in the development of the new stone standard, emphasizes (more…)

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BY MEG CALKINS, FASLA

New technologies can reduce the environmental footprint of the most-used construction material.

FROM THE JULY 2017 ISSUE OF LANDSCAPE ARCHITECTURE MAGAZINE.

Concrete in the 21st century promises to be a more sustainable material, and given the nine billion metric tons used globally each year, it must be. Portland cement, the binding agent in ordinary concrete, has a very high carbon footprint, resulting in just under one ton of carbon dioxide (CO2) released for every ton of cement produced. With 4.2 billion metric tons of the binder used each year worldwide, cement production is responsible for nearly 8 percent of total global carbon emissions. The high lime content of ordinary portland cement contributes about two-thirds of cement’s CO2 impact through the process of limestone calcination. The other one-third of CO2 released is from combustion of fossil fuels.

Technologies to improve the carbon footprint of concrete are currently in the early stages of development, but some, including carbon sequestration in concrete and substantial reductions of cement using energetically modified cement, are now commercially available. Concrete surface products for paving and walls to scrub air pollution, as well as new self-healing concrete products, are also worth investigating. We have heard about some of these innovations for a decade or more in the research community, but many are finally being brought to market—some more quickly than others. Europe is ahead of the United States in the adoption of these technologies, largely because of more rigorous clean air and carbon reduction initiatives.

New technologies in any field can take a long time to move from the laboratory to the marketplace, but (more…)

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BY ZACH MORTICE

The finished and installed concrete cistern. Image courtesy of Concreteworks.

The finished and installed concrete cistern. Image courtesy of Concreteworks.

Hired to design the atrium courtyard of a San Francisco spec office building that features a canted glass roof that channels rainwater, David Meyer of Meyer + Silberberg Land Architects got a few simple instructions from the building’s architects at Pfau Long Architecture—the most interesting of which was to “do something with the water” that the roof would corral into a cascading stream, dripping into the atrium.

But that simple request kicked off a high-wire adventure that saw a three-ton concrete rainwater cistern installed in the courtyard, pushing concrete fabricators to their limits.

Meyer turned to the specialty concrete fabrication firm Concreteworks to manufacture the cistern at 270 Brannan, built by developers SKS. Meyer’s most important request? The cistern had to be one continuous piece. After delays from the general contractor, Meyer says, (more…)

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