Green Manufacturer - July/August 2010

meeting all of those goals. One of the areas (Credit 4) in which a company can achieve points is by purchasing building materials with recycled content.

The requirement is designed to increase demand for building products that incorporate recycled content materials, thereby reducing impacts resulting from extraction and processing of virgin materials, according to USGBC. A company earns 1 point for using building materials with 10 percent recycled content, and 2 points for 20 percent recycled content.

But Here’s Where It Gets Tricky. “Use materials with recycled content such that the sum of postconsumer recycled content plus ½ of the preconsumer content constitutes at least 10 or 20 percent, based on cost, of the total value of the materials in the project,” according to the guidebook “LEED

2009 for New Construction and Major Renovations.” The recycled content value of a material assembly is determined by weight. The recycled fraction of the assembly is then multiplied by the cost of assembly to determine the recycled content value.

OK, whaaa?

USGBC defines postconsumer material as waste material generated by households or by commercial, industrial, and institutional facilities in their role as end users of the product, which can no longer be used for its intended purpose. It defines preconsumer material as material diverted from the waste stream during the manufacturing process, also commonly referred to as postindustrial waste.

Scrap or other materials that have been reworked or reground that can be reclaimed within the same process that generated it are excluded.

Steel’s LEED

The American Iron and Steel Institute (AISI), Washington, D.C.; American Institute of Steel Construction (AISC), Chicago; and the Steel Recycling Institute (SRI), Pittsburgh, provide an example of how manufacturers and other businesses constructing a building using steel can calculate the building material’s recycled content.

One of the two major types of steelmaking processes uses an electric arc furnace (EAF). Beams and columns, channels, and angles are examples of typical products made in an EAF.

In 2007, the year that it was last measured, EAF mills consumed 34,871,600 tons of postconsumer scrap in the production of 61,329,700 tons of raw steel, or 56. 9 percent. In addition, the EAF mills consumed 19,247,000 tons of preconsumer scrap in the production of that 61,329,700 tons of raw steel, or 31. 4 percent.

So a steel product made in an EAF uses approximately 56. 9 percent postconsumer recycled content and 31. 4 percent preconsumer content by weight.

Because steel (the material) and steel (the building product) are the same, the value of the steel building

LEED Credits

LEED 2009 for New Construction and Major Renovations certifications—as well as LEED 2009 for Existing Buildings: Operations & Maintenance— are awarded according to the following scale: