Buildings

Life Cycle Assessment

What Is It?

You understand that when you cut down a tree, send it to a mill, plane it, create boards, and then assemble those boards into a structure, you have had a direct impact on the area where that tree used to be. But what about the ripple effect? How do you account for the energy it took to process and transport those boards to your site? And what happens when you are done with the boards?

This type of thinking speaks to the whole Life Cycle of a material. Assessing the impacts at each stage of the process allows you to appreciate, and value, what is "embodied" in that material. In short, a Life Cycle Assessment measures environmental performance. Life Cycle Assessments are not a "One Size Fits All" tool, and the methodology is evolving, and necessarily, multidisciplinary. Life Cycle Assessment, or LCA, examines the environmental consequences of technology choices through consideration of all stages in the life of a material, from cradle to grave.

How To

LCA begins with the identification of goals and boundary definitions, impact area definitions, and the purpose of the LCA to clarify what decisions it is meant to support. Generally, there are approximately four steps after this initial identification:

• Inventory Analysis - identify and quantify the environmental inputs and outputs associated with a material over its entire life cycle.
• Impact Assessment - characterize these inputs and outputs in relation to a comprehensive set of environmental impacts (such as global warming, water scarcity, habitat depletion).
• Impact Valuation - synthesize the environmental impacts by combining them with stakeholder, or owner, values. This can be lumped with impact assessment.
• Improvement Assessment - opportunities for making changes in the product life cycle which improves its cradle-to-grave environmental performance are identified and evaluated.

ISO 14040:2006, Environmental management - Life cycle assessment - Principles and framework, provides a clear overview of the practice, applications and limitations of LCA to a broad range of potential users and stakeholders, including those with a limited knowledge of life cycle assessment.

ISO 14044:2006, Environmental management - Life cycle assessment - Requirements and guidelines, is designed for the preparation of, conduct of, and critical review of, life cycle inventory analysis. It also provides guidance on the impact assessment phase of LCA and on the interpretation of LCA results, as well as the nature and quality of the data collected.

ISO 14040:2006 and ISO 14044:2006 replace the previous standards (ISO 14040:1997, ISO 14041:1999, ISO 14042:2000 and ISO 14043:2000). The new editions have been updated to improve the readability, while leaving the requirements and technical content unaffected, except for errors and inconsistencies.