Rapidly Renewable Materials – The Green DecisionSubmitted by Tom Bauer on Wed, 08/24/2011 - 00:00
Need help sorting through all the chatter about rapidly renewable materials in roofing? It’s not so different from deciding between a real Christmas tree and an artificial one…try this analogy on for size.
The widely accepted implementation of the United States Green Building Council (USGBC) LEED® guidelines for the building construction industry has introduced a new decision-making matrix for stakeholders in the building construction process. This matrix represents the selection of products that not only meet the requirements of design, but also create opportunities to contribute to earning LEED® credits. This heightened level of scrutiny over the specification of building products has forced product manufacturers to evaluate not only how well their material performs, but also its ability to incorporate key raw materials, including recycled, regionally procured, and rapidly renewable raw content.
The inclusion of specific amounts of raw materials, can help contribute to LEED® Materials and Resources credits including: LEED® MR Credit 4, LEED® MR Credit 5, LEED® MR Credit 6 (LEED® NC ver 3.0). Specifically, LEED® MR Credit 6 deals with use of rapidly renewable materials contained within the building’s construction materials. According to the USGBC, rapidly renewable materials are natural, non-petroleum-based building materials that have harvest cycles under 10 years. Some green building materials are comprised of a composite of rapidly renewable materials and recycled content such as newsprint, cotton, soy-based materials, seed husks, seashells etc. To achieve the credit, the project must use rapidly renewable building materials and products for 2.5 percent of the total value of all building materials and products used in the project, based on cost.
Showcasing products specifically designed to help architects and building owners achieve a project’s LEED® goals and directives is a top priority for Garland. In our own manufacturing process, we have worked to replace traditional petroleum-based products like asphalts with soy-based oils and limestone-based additives with chitin. Chitin is the main component of the cell walls of fungi and the exoskeletons of arthropods, such as crustaceans and insects and contains a high percentage of calcium carbonate necessary in our production process. The soy oil and chitin allow our roofing membranes to contribute to LEED® MR Credit 6 for the inclusion of rapidly renewable content in addition to other areas within the Material Resource credits.
To help explain the rationale and benefits in the decision-making process for the incorporation of rapidly renewable materials, as well as other sustainable raw materials, consider one of the important decisions many of us face each year: deciding between a real or artificial Christmas tree. This simple example of product selection not only highlights the benefits of the use of products conforming to many material resource guidelines, but also demonstrates some of the sustainable foundations comprising the core of the USGBC.
When faced with the decision of real versus artificial, we need to examine the tree with some of the product scrutiny that many building materials face in today’s marketplace. Therefore let’s examine how well the “trees” stand up to the other sustainable building material criteria.
Procurement of Raw Materials & Manufacturing Location (LEED® MR Credit 5)
As with many of our building products, the harvest/extraction and manufacturing location are important factors. To meet the requirements of LEED® MR Credit 5, the product (tree) must contribute to the project goal of having 10 percent or 20 percent of the all of the raw materials extracted and/or harvested as well as manufactured within 500 miles of the “project”. According to the U.S. Department of Commerce, North American Real Christmas Trees are grown in all 50 states and Canada and 80 percent of artificial trees worldwide are manufactured in China. Therefore, we have a clear advantage toward the real tree as long as we can find a tree farm within 500-mile radius of our home, which should not present a problem with anyone other than Clark Griswold.
Rapidly Renewable Content
According to the USDA National Agricultural Statistics Service, it can take as many as 15 years to grow a tree of typical height (6 - 7 feet) or as little as four years. The average growing time is seven years which is well within the defined time period of the USGBC of 10 years. This short recovery period for the growers is achievable due to the fact that for every real Christmas tree harvested annually, one to three seedlings are planted the following spring creating a sustainable industry, making it a model that can be passed on to future generations.
For artificial trees, the concern lies in their fabrication, which is heavily based on polyvinyl chloride (PVC) plastic. To create PVC, you need petroleum, a non-renewable, carbon-emitting resource. In addition, the manufacturing, processing and shipping of artificial trees creates greenhouse gasses (GHG’s). Clint Springer, Ph.D., a botanist and global warming expert at Saint Joseph's University in Philadelphia, says that when making the choice, environmental impact should be at the top of your list. While many consumers may think they are considering the environment when purchasing an artificial tree, they may not understand the entire footprint of that PVC tree.
The simple example of how LEED would view the purchase of the family Christmas tree helps to provide a framework for the newly adopted building product decision process as outlined by the LEED® program. As seen in the example, today’s building materials not only have to meet standard design criteria, but also must incorporate sustainable raw materials to compete in the market. Aligning the project goals with products that meet the established LEED® criteria creates high-performance buildings that are a model of sustainability.