What is a Life Cycle Impact Assessment and why is it important for the built environment?

Life Cycle Assessments, also known as Life Cycle Impact Assessments (abbreviated as LCA and LCIA, respectively), provide objective measurements of the environmental impact of a given product from the procurement of its constituent raw materials, through production and manufacturing, all the way through to decommissioning and end of life (recycling or disposal).

In my mind, an LCA or LCIA is similar to looking at Total Cost of Ownership or TCO. Whereas TCO helps stakeholders understand the complete financial impact of a purchase decision, an LCA/LCIA helps stakeholders understand the total ecological impact of a purchase decision.

Writing for Triple Pundit, Harnoor Dhaliwal and Pete Dunn put together a fairly detailed look at what goes into a proper life cycle impact assessment study and why it matters. Here is an excerpt:

In LCIA, impacts are modeled in three distinct phases: fate, exposure and effect, as shown in Exhibit 1 below.

  • Fate modeling accounts for the characteristics of an emission and the environmental concentration it forms once released. This tells us where in the environment the emission ends up and its final concentration.
  • Exposure modelling looks at the intake level of the emission by considering various routes and modes of intake. In other words, how much of the emission gets eaten, drunk, inhaled, absorbed, etc. For ecosystems, exposure models consider the amount of the emission that becomes bioavailable (i.e., able to be taken up by organisms).
  • Once exposure is assessed, effect models link this information to known toxicity data at those intake levels. This allows us to assess the relative danger of exposure.

Life Cycle Impact Assessment is more and more factoring into sustainable design and construction, but as we continue to understand more about the health and other impacts of various products in the built environment, it is safe to assume that LCAs and LCIAs will only continue to influence our industry.