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Life Cycle Assessment (LCA) Overview

Life Cycle Assessment (LCA) is a "cradle-to-grave" approach for assessing industrial systems. "Cradle-to-grave" begins with the gathering of raw materials from the earth to create the product and ends at the point when all materials are returned to the earth.1

The goal of life cycle assessment (LCA) is to:

  • Quantify or otherwise characterize all the inputs and outputs over a product’s life span
  • Specify the potential environmental impacts of these material flows
  • Consider alternative approaches that change those impacts for the better.
Flowchart showing a life cycle system boundary. The inputs are energy, water, and raw materials. These lead to the system boundary, which includes raw material acquisition; manufacturing, processing, and formulation; distribution and transportation; use, reuse, maintenance; recycle; and waste management. The outputs are useable products, water effluents, airborne emissions, solid wastes, and other environmental releases. Figure 1: Inputs and outputs over a product’s life cycle2
The Sustainable Facilities Tool allows you to compare materials with regard to environmental criteria and life cycle costs in the Explore Section.

It is important to take into consideration the entire life cycle of materials, systems, and the whole building when making purchasing decisions. Only through LCA can the larger environmental image be quantified and compared over their life cycle to find alternatives that benefit humans and society alike.

For more information regarding LCA, continue reading one of the following topics:

Benefits of LCA
Identify the whole environmental impact picture Go beyond just the product “use” phase
Quantify environmental effects such as overall energy consumption or air emissions Recognize inefficient or significant changes in the life cycle phases
Compare alternatives “apples to apples” Reduce overall environmental impact and costs (as in an economic input-output LCA )

Challenges to LCA
Defining LCA boundaries and scope Where do I want to draw the line? What attributes am I interested in comparing against one another? How far down the chain do I want to identify and quantify these material flows, and is that data even available?
Data availability Is data available to quantify material inputs and outputs at all stages of my defined scope? Is this data from a direct source (e.x., manufacturer)?
Quantifying environmental impacts How can these material flows be quantified into environmental categories (e.g., global warming)?
Weighting impacts across stakeholders What environmental category are we most concerned about (e.x., acidification, global warming, energy use) and how does it compare to other environmental attributes?

1 US EPA. "Life Cycle Assessment: Principles and Practice," May 2006 2 DOE LBL | Life-Cycle Analysis