LEED is the nationally accepted benchmark for the design, construction, and operation of high performance green buildings. LEED promotes a whole building approach to sustainablility by recognizing performance in five key areas of human health and environmental impacts: (1) sustainable site development; (2) water efficiency; (3) energy and atmosphere; (4) materials and resources; (5) indoor environmental quality.
LEED and Hot-Dip Galvanizing
As LEED is the most common method for measuring sustainability, often specifiers question whether hot-dip galvanized steel can contribute credits. The answer is yes. The Materials and Resources Credit 4: Recycled Content category specifically focuses on increasing the use of building products with high recycled content, thus reducing impacts caused by extraction and processing of raw metals and ores. Both Steel and Zinc have high recycling and reclamation rates. The recycling rate, which is factored into LEED rating, considers how much of a particular product comes from recycled sources. Because of the high recycling rates, hot-dip galvanized steel contributes points under Credits 4.1 and 4.2 of the Materials & Resources Credit 4: Recycled Content category. The requirements to meet LEED in these categories are as follows:
Credit 4.1 (1 Point) “Use materials with recycled content such that the sum of the post consumer recycled content plus one-half of the pre-consumer content constitutes at least 10% of the total value of the materials in the project.”
Credit 4.2 (1 Point) “Use materials with recycled content such that the sum of the post consumer recycled content plus one-half of the pre-consumer content constitutes at least an additional 10% beyond Credit 4.1 (total of at least 20%) of the total value of the materials in the project.”
Life-Cycle Inventory (LCI) and Life-Cycle Assessment (LCA)
LCI is the study and measurement of the material flows, energy flows, and environmental releases for the production of a defined amount of a product.
LCA is a standardized scientific method for the systematic analysis of ALL material and energy flows, as well as environmental impacts attributed to a product from raw material acquisition to end-of-life management.
While LEED is the most common method for measuring sustainability, there is another measurement method utilized in the marketplace that is a combination of Life-Cycle Inventory (LCI) and Life-Cycle Assessment (LCA). LCI and LCA work in tandem to quantify the material flows, energy flows, and environmental releases for the production of a defined amount of product. LCI is also known as a cradle-to-gate or a gate-to-gate study and is the building block for performing an LCA. LCA is considered a complete analysis (cradle-to-grave) of the true environmental impact of a product. An LCA has four phases: goal and scope, life cycle inventory, life cycle impact assessment, and interpretation.
Environmental critics often point out that LEED uses a relatively simplistic format to gauge the greenness of a product and has a loophole for non-green buildings to be highly rated. The argument about the simplistic format revolves around the fact that LEED offers credit for recycled content of materials used and energy consumption and air quality impact over the useful life, but end-of-life implications, such as recyclability, are not considered. Even more frustrating is the loophole in the credit system. Industry professionals maintain a LEED plaque is not necessarily analogous to sustainable development. Because each LEED credit has the same weight (1 point), it is possible to garner enough credits for a high LEED rating without obtaining a single point in energy efficiency. Critics argue this loophole allows some to undermine the rating system, and receive awards for being “green” when in fact the building’s environmental performance is poor. LEED is still a useful rating system that provides a positive contribution to advancing sustainable development, but for a true picture of an environmental impact, we believe that an LCI and LCA assessment should be taken into consideration.