Building Green

The Whole Picture

Life-Cycle Assessment Recognizes the Green Benefits of Zinc

Zinc is an essential mineral found in every cell of every living organism in every ecosystem on the planet. Naturally present in the air we breathe, the water we drink and the Earth we cultivate, zinc now is surfacing in the building specifications of eco-savvy architects and engineers across the globe. Zinc offers a combination of versatility, durability and sustainability that makes it an attractive choice for many projects.

Zinc manufacturers have long touted the environmental attributes of zinc, but sustainability leaders, like the Washington, D.C.-based U.S. Green Building Council, have been slow to recognize the metal’s value as one of the few building materials that can be recycled indefinitely without loss of physical or chemical properties.

Life-cycle assessment is gaining prominence as a way to measure a product or material’s green attributes. According to the Washington-based U.S. Environmental Protection Agency, LCA assesses the environmental aspects and potential impacts associated with a product, process or service by compiling an inventory of relevant energy and material inputs and environmental releases; evaluating the potential environmental impacts associated with identified inputs and releases; and interpreting the results to help you make a more informed decision.

Because LCA is a better way to assess a material or product’s environmental attributes from cradle to grave, architects and engineers are turning to LCA to assess materials for their projects. The Portland, Ore.-based Green Building Initiative already is using LCA in its Green Globes green-building rating system, and USGBC is considering integrating LCA into its LEED system. In short, that means zinc finally is being viewed in a new light.

BUILDING A CASE

The International Zinc Association, Brussels, Belgium, currently represents 42 members and 87 affiliate companies, which account for more than 80 percent of the Western-world’s zinc production and 50 percent of world production.

IZA is using LCA data to establish,improve and communicate the environmental advantages of using zinc products manufactured by its members. In 2006, IZA launched Zinc for Life, a three-year marketing program dedicated to providing sound scientific information about the sustainability attributes of zinc.

Boston-based Five Winds International, a global-consulting firm in the fields of sustainable development and environmental performance, is working closely with IZA to produce a solid base of LCA data that product manufacturers, architects, engineers and other key stakeholders can use when modeling their products and projects.

In accordance with international standards regarding LCA, such as ISO 14040-14044, Five Winds International is working to track and document zinc’s environmental impact from resource extraction through disposal. “We are looking at some of the key end uses for zinc and getting decision-makers in those sectors the information they need to make choices that contribute to sustainable development,” explains Jennifer Cooper with Five Winds International’s Toronto office.

Through LCA studies like these, IZA hopes to provide a scientific benchmark for demonstrating zinc’s potential for improving the overall environmental performance of a building, as well as for reducing zinc’s impact at the end of its useful life.

LEED is probably the most recognized green-building rating system on the market today. While many of its categories are areas in which the use of zinc can contribute to a building’s environmental attributes, the one category conspicuously absent from the list is end-of-life recycling. This is something that IZA has been working closely with USGBC to change. According to Scot Horst, a sustainable materials consultant with 7group, Kutztown, Pa., and chair of the LEED Steering Committee, a new version of LEED incorporating LCA is expected to debut this fall, pending consensus by the organization’s membership.

GIVING CREDIT WHERE IT’S DUE

In this day and age, using materials that pollute during manufacture, use and disposal falls far short of green-building initiatives. During the last 40 years, roofing materials have accounted for 7 to 10 percent of existing landfill space.

Zinc, on the other hand, is far less likely to enter the waste stream. When properly installed, a zinc roof or wall system can last up to 100 years. In fact in Europe, where zinc use is more prevalent, roofs, gutters and railings have been known to last for generations. After their “useful life” these products are then recovered and reused at an impressive rate. In Western Europe, for example, an extraordinary 90 percent of rolled zinc is recovered from roofs and rainwater systems every year, amounting to the equivalent of 110,230 tons (99999 metric tons).

Zinc also is recycled at all stages of production and use. Furthermore, the level at which zinc is recycled increases each year in concert with advances in zinc production and recycling technology. Today, more than 80 percent of the zinc available for recycling is actually recycled, and that percentage is likely to improve as demand for zinc products grows.

As the building industry migrates toward green practices, zinc will continue to play an increasingly important role in the development of truly sustainable buildings.

This article was written by Steve Collins, President of Cranston, R.I.based Desana Partners Inc., and reprinted from MetalMag: http://www.metalmag.com