Sustainable By Design: Nature’s Best Ideas For Buildings
By Anne Vazquez, TFM Managing Editor
Published in the November 2007 issue of Today’s Facility Manager
To most facility professionals, environmentally friendly products and systems are no longer a foreign concept. And the “green movement” is steadily moving into the mainstream as more people in all walks of life become aware of the possibilities beyond the status quo. As with nearly all areas of outfitting a facility, it’s important to look further than the face value of products and processes touted as sustainable to see what the origins are.
In a discipline hovering on the periphery of sustainability, nature itself is being explored for new ideas by some researchers, manufacturers, and end users. Called biomimicry, this approach can be defined as the “science that studies nature’s best ideas and then imitates these designs and processes to solve human problems.”
A well known example of biomimicry is the hook and loop fastener, patented in 1951 by George de Mestral, a Swiss engineer. While out for a walk, de Mestral was plagued by burrs that lodged themselves on his pant legs as well as on the fur of his dog. Intrigued by the strong fastening power of the burrs, he studied them and found that each burr was covered with hundreds of tiny hooks that latched onto the loops on textiles—or fur. He went on to develop a man-made fastener modeled after his discovery in nature. Shortly after securing the patent, de Mestral founded the Velcro company to market the product.
Biomimicry (also sometimes referred to as “bio-inspired design,” “biomimetics,” or “bionics”) was actively re-introduced into public discussion in the late 1990s by Janine Benyus, a life sciences writer and author ofBiomimicry: Innovation Inspired by Nature.As a co-founder of the Biomimicry Guild located in Helena, MT, Benyus, along with her colleagues, consults with manufacturers, designers, and end users on the potential of biomimicry for applications in human activities.
“The definition of success in the natural world is keeping yourself alive and keeping your offspring alive 10,000 generations from now, and that’s a tough thing to do,” said Benyus in a speech at the University of California in 2006. “We’re headed through an evolutionary knothole we’ve never seen before. But we can be informed by the wisdom of these adaptations.” The ideas in biomimicry are seemingly as endless as the natural world, and the range of products studied is vast.
Applications that have made their way to market include exterior coatings for buildings that mimic the self cleaning properties of a lotus leaf. German scientist Wilhelm Barthlott discovered this “Lotus Effect” after studying the surface of a lotus leaf and its microscopic spikes, which make it difficult for water to adhere to them. As rainwater falls on a coating modeled after the lotus leaf, it sloughs off dirt and debris as well. This results in a building that is self cleaning to a large extent, which saves water and detergents that would normally be used to wash a building exterior.
Adhesives are another area where researchers are learning from nature’s blueprint. In October, a team at the Indian Institute of Technology announced its work on finding an adhesive modeled after the pads on the feet of tree frogs. These amphibians can secure themselves to many surfaces, and the scientists on this project wanted to find out if they could mimic the recurring adhesion mechanism.
They had conventional sticky tape in mind as the challenge; when this type of tape is pulled off of a surface, cracks spread through the adhesive. This makes it possible to peel the tape, but the cracks remain and are part of the reason the tape loses its ability to be re-adhered to a surface. The researchers found that a pattern of tiny channels on the frogs’ foot pads increased their adhesion to a surface, while the channels prevented the spread of cracks when the feet pulled away from surfaces. They then designed elastic layers embedded with channels filled with either air or fluids beneath an adhesive layer. The result, according to the team, was a material that can be peeled off and reused without losing adhesion strength.
Biomimicry is also being used to create whole buildings systems that reduce the amount of energy derived from fossil fuel sources. When executed correctly, building systems designed to mimic nature can result in energy savings as well as material use reduction.
Termites were the inspiration for the passive cooling and ventilation system used in a Zimbabwe high rise. In 1996, architect Mick Pearce worked with engineers at the Zimbabwe office of Arup Associates to build the 340,000 square foot retail and office facility in the city of Harere.
The building was modeled on the self-cooling mounds of Macrotermes michaelseni, termites that maintain the temperature inside their nests to within one degree of 31°C (87.8°F), day and night, while the external temperature varies between 3°C (37.4°F) and 42°C (107.6°F). The complex layout of the termite mounds was modeled and then studied in order to duplicate this effect for a passive cooling and ventilation system in the building. As a result, the facility did not require an air conditioning system, and the building reportedly uses 10% of the energy of a conventional building its size.
Biomimicry, by definition, is not inherently sustainable. As with any type of product or process, the materials used to fabricate and the process used to manufacture the item are important parts of the life cycle. Just because something is modeled after a natural process or design does not automatically make it environmentally friendly. Still, at least some of the discoveries predicated on biomimicry do fit the sustainability criteria currently specified by facility professionals. And, as with all sustainable strategies, it is important to ask questions about every aspect of the production process.
For more information on biomimicry developments, visit the Biomimicry Guild at www.biomimicryguild.com.
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