Life Cycle Assessment of Materials and Products
We along with others involved in green building have recognized that the materials and products used in buildings make significant environmental impacts long before they are installed.
The impacts include the amount of embodied energy used to extract raw materials, transport them, and then manufacture the product. Also included are the associated fuel that’s used and carbon footprint of the process, which contributes to smog, pollution, ozone depletion and global climate change. Added into the equation is the disposal of products at the end of their service life which contributes to environmental impacts through the use of energy to remove and relocate them plus the impact of disposal in landfills, or incineration, or other disposal methods. Because of these impacts over the full life of products and materials, there is an interest in finding a reliable method for quantifying and comparing the environmental impacts of all specific building products.
These details can be researched in a number of available databases. We have been working on our own research from the building materials available to us in Western Mass. It is where they come from, transportation, and all the criteria above.
The impact of building a green home is more than just how efficient the home is but how the entire process impacts our environment. We also try to reuse and recycle materials as much as possible, as this usually has the lowest environmental impact.
A life cycle assessment (LCA) is an analysis of every component or phase of a product’s manufacture and use. The life cycle begins with the so-called “cradle” of the product – the extraction of raw material and transportation to the manufacturing site, which is called the extraction phase. Next manufacturing happens, where labor, equipment, by-products, and energy used to create the building material is calculated. The finished products get transported to supply facilities and next to the construction phase of being transported to the job site and installed into the building. After installation and the building are completed, the materials live out their use phase; if maintained correctly, they hold up as expected over time. Finally, at the end of the useful service life of the building or the material, then the end-of-life phase (so-called “grave”) comes in where decisions about disposal, recycling, or re-using are made.
Because different LCA datasets and software can produce results that may not be compatible, just using the one tool to focus on a partial or simplified impact analysis may provide enough information to weigh the relative benefits during material selection. LCA software, databases and tools commonly focus (sometimes exclusively) on CO2 or greenhouse gas emissions (CO2e) and their impacts on climate change. More complete lifecycle assessments compliant with ISO 14044* should address other environmental impacts such as ozone depletion, acidification, eutrophication (too many nutrients especially phosphates and nitrates in water), ozone (smog) formation, chemical hazards, human particulate effects, and human carcinogenic effects.
* ISO 14044:2006 covers life cycle assessment (LCA) studies and life cycle inventory (LCI) studies.
The goal is a home built with sustainable, non-toxic construction, using durable, resource efficient building materials. The home will have a healthy indoor environment, ideally a good solar siting for light, heat, and power, and even consideration of water use and recycling of wastes into nutrients.