Environmental performance of aluminum building components and LCA
Tuesday, January 2, 2018
The following was excerpted from "Life Cycle Analysis and Aluminum Exterior Building Components" by Ben Mitchell, MBA, AkzoNobel and Vikas Ahuja, thinkstep, featured on www.designandbuildwithmetal.com
Multiple environmental considerations must be taken into account when designing metal architectural systems, including curtain walls, panels, commercial windows, sunscreens and louvers. Fortunately, Life Cycle Analysis (LCA) and its associated tools are helping architecture/engineering/construction professionals address these considerations. LCA offers ISO guided, science-based, standardized measures of environmental performance. Assessment can be performed for a specific product, a system or a whole building and includes ALL stages of use, from raw material extraction through end of life (i.e., cradle-to-grave). Many third-party green building rating systems, such as the Architecture 2030 Challenge for Products and Leadership in Energy and Environmental Design (LEED), award points for buildings with Whole Building LCA and the use of products with EPDs.
LCA has grown out of the simple energy analyses that became common in the 1960s and now includes examining the overall environmental burden of products and buildings. Recent efforts have focused on standardizing the methods of communicating environmental impacts, as well as organizing and quantifying costs. As a result, product category rules (PCRs) and environmental product declarations (EPDs) have been developed as part of the LCA framework.
PCRs are defined in ISO 14025, Environmental Labels and Declarations – Type III Environmental Declarations, as “a set of specific rules, requirements and guidelines for developing Type III environmental declarations for one or more product categories.” Consensus-based documents developed by stakeholder organizations, they set parameters for the type of data used in an EPD. Per ISO 14025, there must always be a PCR before a manufacturer can produce an EPD. EPDs contain a summary of LCA results and are the documents used directly by a designer – however, it is necessary for designers to become familiar with PCRs as well as EPDs as a means of verifying that individual EPDs comply with methodological prerequisites.
Aluminum exterior building components contribute to the environmental performance of a building in various ways. Some of the benefits of aluminum are intrinsic. For example, 65% of all the aluminum ever produced is still in use and recycled aluminum uses only 5% of the energy required to produce primary aluminum. Furthermore, aluminum can be recycled over and over with no loss of physical properties. The aluminum recycling industry has tripled in recent decades, due to the material's increasing popularity.
Aluminum Building Components And LCA
Environmental impacts associated with the pretreatment and/or finishing phase of aluminum require particular consideration. More...
AEC LCA & EPDs
Recently, the Aluminum Extruders Council released the most comprehensive industry-wide set of Environmental Product Declarations (EPDs) to date that document the environmental performance of aluminum extrusions produced in the U.S. and Canada.
The EPDs quantify the “cradle-to-gate” lifecycle environmental impacts of aluminum extrusions. One EPD is for thermally-improved extrusions – of particular interest for fenestration applications – and one covers extrusions that have not been thermally improved. Both provide data for mill finish, painted and anodized products, so architects and designers can assess the environmental impacts of finishing and thermal improvement decisions. For details go to AEC.org/EPD