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Steel Framing Compared to Wood Framing—Which is a Better Environmental Choice? |
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The pursuit of producing a “green” building is often reduced to successfully meeting the requirements of a checklist from one of several green rating programs, with a focus on the use of recycled products; yet, no accountability is required regarding the environmental impact of the production of the original material or its recycling process. The comparison of steel framing vs wood framing provides a solid example of the importance of the environmental impact of recycled products when choosing a building material. Only after objectively comparing the adverse environmental impacts of a building material to its favorable impacts, can a more accurate judgment be made. Dr. Jim Bowyer, of Dovetail Partners Inc., published a paper highlighting statistical data and offering conclusions regarding the comparison of steel and wood framing. Four factors noted in the article are highlighted below with a brief comparison statement. To read this very interesting article in its entirety, click this link: MATERIALS SELECTION IN FRAMING--IS STEEL FRAMING A GOOD ENVIRONMENTAL CHOICE? Further articles are available at www.dovetailinc.org Embodied Energy: is the total quantity of energy consumed in raw material extraction, transportation, and processing through every step in manufacturing from primary to finished products. Framing interior non-load bearing walls or partitions using steel studs requires almost exactly twice as much energy as framing the same walls using wood. For exterior walls, in which the gauge of the steel must be adjusted to resist loads, embodied energy associated with steel framing is three to four times that of wood. Source of Energy Used in Manufacture: The North American steel industry is fueled almost entirely by fossil fuels. In contrast, the lumber industries of the U.S. and Canada use scraps of bark and what was once waste wood to produce their own energy in large industrial boilers and co-generating equipment. As a result, the lumber industry is 50 to 60 percent energy self-sufficient overall. From an environmental point of view the difference is both significant and important, since energy generation from wood and other biomass is carbon neutral and less polluting than energy generation from fossil fuels Conductivity: Steel is about 400 times more conductive than wood, and a steel stud is about 10 times more conductive than a wood stud. To achieve thermal equivalence to wood framing, steel framing will require added layers of expanded polystyrene (EPS or XEPS), which has a substantial environmental impact in its production--often equal to 50 percent or more of the embodied energy of the steel itself. Emissions: Emissions to air and water are also dramatically different for the two wall framing systems, with effluents and emissions of specific materials and pollutants being between 1.6 and 41 times higher for steel manufacturing than for wood for an interior wall. Because of the greater steel cross-section required to resist loads, the embodied energy and emissions associated with exterior, load-bearing wall structures are much higher than for interior In addition, the production of steel walls requires the use of 23 times more water than wood production. |
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| The information in this article is based upon the paper presented by Dr. Jim Bowyer and associates of Dovetail Partners, Inc. We encourage you to view the paper in its entirety. We have posted it at this link.
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