There’s a lot more to a story than what the blurb at the back of the book tells you. Green builders realize the benefits of sustainable building, partly because they understand the interconnected nature of life on Earth. So it’s no surprise then that the industry has embraced life cycle assessment (LCA) to accurately analyze the full lifespan of a building in its entirety rather than just looking at the sum of the parts that went into the building itself.
What is a life cycle assessment?
A life cycle assessment is a methodology used to measure the impact that a product or process has on the environment, from the beginning of the process (raw material extraction) to the end of the process (disposal). These assessments can be used to analyze anything from building materials to furniture.
LCAs are used to measure both material and energy inputs and outputs, evaluate the effects of those inputs and outputs and formulate the data into useful information for understanding the outcome of a particular product or process on the air (i.e. ozone depletion), land (i.e. waste) or water (i.e. pollution).
Some background on life cycle assessments
According to Environment Canada, some aspects of LCA were in use as far back as the 1970s, but the comprehensive technical framework for the process has only evolved within the last several years. Society of Environmental Toxicology and Chemistry (SETAC) is largely responsible for developing LCA into what it is today, though a great number of other organizations have also been involved in its development, such as Environment Canada and the Canadian Standards Association in Canada and the EPA in the U.S. The International Organization for Standardization (ISO) have taken LCA a step further by developing international standards for the methodology.
Benefits of an LCA
Life cycle assessments are a potent tool green builders can use to choose the most environmentally sound products and processes. LCAs analyze what the effects of a transfer from one medium to another is, such as eliminating air emissions by creating a wastewater effluent. This way they can track what happens with individual components of a building to come up with accurate data on the sustainability of an entire building over its entire life cycle.
Assessing environmental impact is deceiving. Though it’s easy to see how bamboo flooring is a better option for the environment than a typical carpet, assessing the sustainability of two similar bamboo floors isn’t so obvious unless conducting an LCA. How far did the flooring travel before eventually getting installed? How much embodied energy went into it? What effect will its disposal have? Though one product on the surface could appear to produce more carbon emissions, when its entire environmental impact is taken into account (e.g. effects on air, land, and water) it could be far less harmful for the environment than the product that emits less carbon.
Information is power. Empowered by the comprehensive data that an LCA provides, it becomes much easier to gain stakeholder acceptance (i.e. government, citizens) because builders have reliable data to point to when backing their case for a building.
Resources for conducting an LCA
The National Risk Management Research Laboratory published Life cycle assessment: Principles and Practice, a free e-book that covers the whole process of conducting an LCA.
A number of software tools are available to help perform life cycle assessments. The Whole Building Design Guide hosts a list of life cycle costing, assessment and management, and the U.S. Department of Energy maintains a comprehensive directory of building energy software tools.