Documenting the Carbon Impact of Laminated Veneer Lumber Production

 

Laminated veneer lumber

Research Forest Products Technologist Richard D. Bergman continues his good work for the environment with a recent publication, Life-Cycle Inventory Analysis of Laminated Veneer Lumber Production in the United States.

Bergman’s study found that documenting the actual environmental performance of building products is becoming widespread and important because of concerns that some organization’s green-marketing claims are actually misleading. This is known as “greenwashing” in the business and borrows from the term whitewashing.

Developing environmental product declarations (EPDs) for building products is one way to provide scientific documentation that counters efforts to greenwash. Life-cycle inventory (LCI) data are the underlying data for subsequent development of life-cycle assessments (LCAs) and EPDs. EPDs are similar to nutritional labels for food.

This report follows data and reporting requirements as outlined in the Product Category Rules (PCR) for North American Structural and Architectural Wood Products and contains the LCI components for producing a North American EPD. At present, many EPDs for structural wood products made in North America exist. LCI compiles all raw material and energy inputs and outputs associated with the manufacture of a product on a per-unit basis within defined system boundaries. These boundaries can be limited to only one stage within the product life-cycle.

Multiple sequential LCI stages are usually combined to produce an LCA. LCAs describe the total environmental impact for a particular product. Many engineered structural wood products have been developed in the last several decades; for example, laminated veneer lumber (LVL ), which is comprised of many thin layers of dry wood veneers glued together with resins to form lumber-like products. LVL is designed to be used in the same manner as solid wood  products such as sawn lumber. Structural wood products such as LVL used in building construction can store carbon for long periods, which is typically greater or far greater than the carbon dioxide emissions released during manufacturing.

Environmental product declarations based on LCA data are an important means of documenting the environmental performance of building products. The International Organization for Standardization (ISO) requires that underlying LCI data be recent; this study updates the LCI data for LVL needed to develop an updated EPD. The amount of carbon stored in LVL exceeds total CO2 emissions during manufacturing by about 350 percent.

Cooperators include the USDA Forest Service Forest Products Laboratory, Madison, Wisconsin, and the Consortium for Research on Renewable Industrial Materials, Seattle, Washington.

Life-Cycle Analysis of Redwood Decking

Forest Products Laboratory (FPL) scientist Rick Bergman recently led a life-cycle assessment study of redwood decking in the United States. In cooperation with the Consortium for Research on Renewable Industrial Materials (CORRIM), the School of Environmental and Forest Sciences, University of Washington, and Humboldt State University, Department of Forestry and Wildland Resources, researchers compared the use of redwood with three other decking materials.

Fig_01

Complete life cycle from regeneration of trees to disposal of wood materials

Life-cycle inventory (LCI) and life-cycle assessment (LCA) are terms we’ve been hearing around FPL in recent years with increasing attention to “green building” practices. The term life cycle connotes a fair, holistic assessment to consider all aspects of the product: raw-material production, manufacture, distribution, use, and disposal, including all intervening transportation steps.

The goal for Bergman and his fellow researchers was to conduct an LCI of California redwood (Sequoia sempervirens) decking that would quantify the critical environmental effects of decking from cradle to grave. Using LCI data, the scientists produced a life-cycle assessment for redwood decking. These results were used to compare the environmental footprint of redwood decking to similar decking materials made of plastic (cellular PVC) and wood–plastic composites.

Results of the study showed the total energy expended for redwood was substantially lower than that for the other decking products. The ranking for redwood decking was the result of the product’s ability to store carbon, originally sequestered from the atmosphere, over the life of the product.

 

 

A Tool for Environmental Decision Making

Life-cycle assessment (LCA) is a technique used to assess environmental impacts associated with all stages of a product’s life. Researchers in the Forest Products Laboratory’s Economics, Statistics, and Life Cycle Analysis Research group use this technique to study a wide variety of wood products, from building materials to bioenergy resources.

The goal of LCA is to compare the full range of environmental effects assignable to products and services. LCA results can be used to improve processes, support policy, and provide a sound basis for informed decisions.

Fig_02

Life Cycle Assessment phases

According to the Environmental Protection Agency (EPA), an LCA can assess the environmental aspects and potential impacts associated with a product, process, or service, by the following:

• Compiling an inventory of relevant energy and material inputs and environmental releases;
• Evaluating the potential impacts associated with identified inputs and releases;
• Interpreting the results to help make a more informed decision.

The EPA also describes the major stages in an LCA study as: raw material acquisition, materials manufacture, production, use/reuse/maintenance, and waste management. They go on to advise that “Companies, federal facilities, industry organizations, and academia can benefit from learning how to incorporate environmental performance based on the life cycle concept into their decision-making processes.”

The four basic phases of conducting a Life Cycle Assessment are: goal and scope definition, inventory analysis, impact assessment, and interpretation. LCA studies include all stages, but a life-cycle inventory (LCI) study does not include stage 3, the impact assessment.