A recent study by Arlington, Va.-based Deloitte Touche found that 95 percent of consumers would buy green products if they had the right information. But what is “the right information?” The marketplace is bombarded with hundreds of eco-labels, green product claims, environmentally responsible practices and sustainability goals. More specifically, certain products make claims of having a high level of recycled content, being recyclable, biodegradable, generating low emissions and possessing low embodied energy. How can anyone be sure that these claims are scientifically valid?
One tool that is available to quantify sustainability or environmental impact is a life-cycle assessment, or LCA report. Sometimes also referred to as life-cycle analysis, LCA is an analytical process to estimate the sustainability profile of a product, process or service. It is not to be confused with a life-cycle cost analysis, which evaluates the monetary cost of a product throughout its estimated service life. LCA first was used in the 1970s for process improvement. It has been very popular in Europe and has grown in importance in North America since the 1980s. Some products that have been improved based on LCA include jet engines, soft drinks, cups, diapers, computers and building products.
Data from LCA reports of specific products or processes are used to populate life-cycle inventory, or LCI, databases, which in turn are used to calculate environmental impacts of complete assemblies or systems such as wall or roof assemblies. An example of an LCI database is the U.S. LCI database, which is administered by the Golden, Colo.-based National Renewable Energy Laboratory. It can be found online at www.nrel.gov/lci/.
Building an LCA
LCA is based on the premise that all processes or products have some impact on the environment during raw-material extraction, manufacturing, distribution/transportation, use, maintenance and disposal or recycling. The LCA process is governed through measures such as the ISO 14000 family of standards from the Geneva-based International Organization for Standardization and ASTM standards from West Conshohocken, Pa.-based ASTM. The guidelines describe the process that is to be used, but each LCA itself can be unique due to the assumptions or boundaries that are established in the scope of the analysis. Per ISO or ASTM standards, any and all assumptions and details of the analysis must be transparent to a team of peers that review and approve final LCA reports.
One approach to LCA is referred to as cradle-to-grave. It encompasses impacts from extraction or harvesting of raw materials through manufacturing, transportation and waste or disposal at the end of life. But if a product can be reused or recycled rather than disposed of at the end of its life, a cradle-to-cradle analysis can be done. Within that complete cycle there are other analyses possible, such as evaluations of impacts within a given manufacturing process or throughout transportation, storage, building use, recovery and re-use of a product.
In an LCA evaluation, the basic process data measured or collected from a manufacturing process are used to determine environmental impacts. The raw data include all material inputs and outputs, as well as energy, air and water emissions and various forms of waste. These data are converted to environmental impact data based on several categories, including: global warming potential, stratospheric ozone depletion, ground-level ozone, acidification, eutrophication, aquatic toxicity, human health, fossil-fuel depletion, mineral depletion and land use.
For example, a manufacturing process may emit some quantity of CO2, either on-site or indirectly through its energy usage. The measured level of CO2 emissions then is analyzed for its contribution to the afforementioned impact categories. After the data is measured and collected, a weight is assigned to each category, taking into account social considerations. For example, today climate change potential is more important to society than ozone depletion. A few decades ago, the relative weighting was just the opposite.
A great illustration of how LCA can change the way we perceive the environmental impact of something is summarized in a recent study by the University of California, Irvine. The study focused on green turfgrass lawnscapes within urban settings. At first glance, one might think that such an area would be helping the environment because grass removes CO2 from the atmosphere and stores it as organic carbon in the soil. The study, however, found that greenhouse-gas emissions coming from fuel consumption related to the production of fertilizer, mowing, leaf blowing and other lawn-management practices actually were four times greater than the amount of carbon stored by the turfgrass areas.
Complex and CompleteSo how can you conduct an LCA?
The short answer is that it’s not easy. The process is very complex and comprehensive. In most cases, the work is conducted by an LCA consulting firm or practitioner. Depending on the scope of the work, the entire process can take up to one year to complete.
An LCA can be used to create industry-wide averages of the environmental impact of a standard process. Individual manufacturers within that industry can use it as a benchmark against which to compare the impacts of their processes and look for ways to improve their systems. It also can help a manufacturer determine the environmental impact of products or raw materials that are purchased for a manufacturing process.
Comparing an LCA report of one product against another is discouraged, but often is done for marketing purposes. The variation in boundary conditions or assumptions between different LCA reports and the source, validity and accuracy of data used in each study often are difficult to verify. This makes it potentially misleading to simply compare one LCA study to another.
Until a few years ago, most green-building certification programs didn’t use LCA data for material selection. Today, many standards in the building industry contain an LCA component, such as: ASTM; the LEED v2009 Pilot Credit for LCA from the Washington, D.C.-based U.S. Green Building Council; and ASHRAE/USGBC/IESNA/ANSI Standard 189.1-2009, Standard for the Design of High-performance Green Buildings from Atlanta-based ASHRAE.
Metal Industry Impact
LCA will reveal the embodied energy found in material manufacturing. Any heating or melting process can consume large quantities of energy that could have a negative environmental impact. Primary metal production is subject to this analysis. Other construction products consume large amounts of energy for their manufacturing processes also.
The use of LCA in codes, standards and green-building initiatives allows designers to choose a performance-based approach instead of using prescriptive measures. The prescriptive criteria at risk for metal products include provisions for high recycled content and full recyclability.
The existing LCI databases are lacking current and accurate data for materials such as steel, aluminum, zinc and copper. The trade associations representing those primary metals, however, have been working diligently to correct that. In 2010 the LCI databases are expected to be updated with improved data being captured and analyzed by trade organizations. Similarly, LCI data for many metal building envelope assemblies are lacking. The metal-construction industry is taking steps to correct that situation as well, with LCA projects planned to evaluate environmental impact on the primary processes used and to populate LCI databases wherever possible.
Where We’re Headed
As we look ahead, LCA increasingly will become a necessary tool for the metal-construction industry. The growing popularity of LCA in regulations, legislation and in voluntary green certification programs is obvious. LCA data will be the basis for environmental product declarations (EPDs), which already are being used in Europe and the Pacific Rim. There even is pending federal legislation in Washington to require EPDs for products sold in the U.S.
LCA data will be important as a form of validation for environmentally preferable products, a requirement that the U.S. federal government is leaning toward. These would be products that federal agencies would need to look at preferentially compared to other types of products in their procurement process. As a process improvement tool, we likely will see an increased use of LCA by metal component manufacturers and suppliers to find ways to reduce the environmental impact of their processes. And as more importance is placed on performance-based regulations and initiatives, LCA will play a larger role in place of prescriptive criteria for metal components.
There is no doubt that we will be hearing more about life-cycle assessment in the construction industry. The concept is fairly simple, but the details and process can be daunting. This train has already left the station and some would say that it is something our industry needs to jump on before it’s too late.
- Scott Kriner, LEED AP, is president of Green Metal Consulting, Macungie, Pa., and technical director of the Glenview, Ill.-based Metal Construction Association. He can be reached at firstname.lastname@example.org.