Life Cycle Thinking

It can be hard to figure out whether a building product is sustainable when you do not have access to any scientific measurements of the energy and natural resources necessary for its creation. This has been one of the big issues with plastic building products over the last few years. The plastic polymer industry felt it was apparent it was a leader in energy resource efficiency, and the information to back this up will soon be publicly available on the Web.

For the past decade, other material industries have contributed their aggregated life cycle assessment data to national and international databases. Plastics has not, until now. This year, current plastic life cycle data will be available for the processes from the raw materials all the way to the pellet. With this information, plastic molders, plastic formers, plastic shapers, and plastic fabricators can determine the complete life cycle inventory for their plastic products—and design professionals can see first-hand how energy-efficient plastics can be.

Life cycle assessment (LCA) analyzes a product’s environmental impact throughout its ‘cradle-to-grave’ life span. This involves a holistic look at the ‘big picture’—the energy consumed, the raw materials used, and the extent of environmental impact at various stages of a product’s manufacture, use, and end-of-life.

Through a diagnostic look at quantitative measurements of these inputs and outputs, it is possible to provide a benchmark of these important criteria from which efficiencies can be identified and improvements can be made across the product life cycle. This assessment involves coming up with improved processes, cleaner technologies, and an overall optimization of raw materials, energy, and emissions.

As discussed in previous issues of Modern Materials, the Plastics Division of American Chemistry Council (ACC) recognized the growing need for a database of information about various plastic product life cycles.1 As such, it employed International Organization for Standardization (ISO) 14000, Life Cycle Assessment, which is based on a three-component model:

  • an inventory of materials/energy used and environmental effects released from all stages in the life of a plastic product or process—from raw material acquisition to ultimate disposal;
  • an impact assessment examining potential and actual environmental and human health effects related to the use of resources and environmental releases; and
  • an interpretative analysis of the changes needed to bring about environmental improvements in the plastic product or process.

This methodology was used for nine major plastic polymers (i.e. cradle to pellet) and four polyurethane plastic precursors. This data provides current information, which can then be used as a tool to optimize the energy efficiency of a plastic product’s use-phase, minimize the environmental impact of its production, and allow comparisons between similar products in categories like greenhouse gases and climate change.

“Consumers are increasingly interested in the world behind the products they buy. Life cycle thinking implies that everyone in the whole chain of a product’s life cycle, from cradle to grave, has a responsibility and a role to play, taking into account all the relevant external effects.”
— Klaus Toepfer, former United Nations

The need for providing life cycle data that is up-to-date and publicly accessible, but aggregated to protect proprietary and individual company data, has been a driving force in the creation of the U.S. Life Cycle Inventory (LCI) National Database project—a collaboration of industry, government, and consultant groups. The goal of this national project is to develop an accessible database for commonly used materials, products, and processes.

Using a ‘cradle-to-grave’ focus, data from the aluminum, steel, and wood products industry provide the important transformation process information to conduct a full product life cycle (Figure 1).  The new LCI data from the ACC’s Plastics Division will provide the basis for completing the ‘upstream’ data for the life cycle of plastics products (as this can sometimes be difficult to obtain). As shown in Figure 2, the ACC’s Plastics Division project now sets the stage for the collection of specific plastic product fabrication, use phase, and end-of life data for the majority of plastics made today.

LCI data has become increasingly available, given the instant access of the Internet and the development of commodity databases through consultants and private studies. The U.S. LCI database project, with more and more transformation processes for key raw materials, provides a number of users and uses with key data, such as:

  • LCA tool developers;
  • manufacturers wishing to benchmark against others;
  • companies for product assessment and labeling;
  • researchers and students; and
  • the general public, along with non-governmental agencies, and think-tanks who want to use actual LCA information.

Only when we can look at all the data from cradle to grave can we determine the impact a plastic product has over time. With this knowledge, we should be able to make comparative judgments about sustainable building products.

About the Author

Mike Levy is the life cycle management coordinator for the Plastics Division of American Chemistry Council (ACC). A frequent contributor to Modern Materials, he can be contacted via e-mail at


1 See this author’s “The Future of Life Cycle Assessment” and “Plastics & the LCI Project” in the November 2005 and April 2006 issues of Modern Materials, respectively.