A life cycle assessment (LCA) is a methodology used to quantify the environmental impacts of a material, product, process, or activity throughout its entire life cycle – from the beginning stage of raw material extraction thru to disposal or recycling at the end of its useful life. The LCA process is governed by ISO 14040 and 14044, while LCA data is collected and then “modeled” using unique software to determine the environmental burdens associated with each stage of “life”, divided into modules A, B, C, and sometimes D. Which modules are included in the assessment are entirely based on the items makeup and inputs/outputs.
Below is a high-level overview of key life cycle stages of a product, particularly a building material, where impacts are calculated and assessed based on their environmental effect.
Raw Material Acquisition (A1): This stage evaluates the impacts associated with the extraction of raw materials and their subsequent processing, or the processing required to recycle materials into useable forms for production.
Transportation from Supplier to Manufacturer (A2): This stage assesses the impacts of moving materials from the raw material or recycling processor to the manufacturing facility.
Manufacturing of Material (A3): This stage evaluates the multiple processes that transform raw or recycled material in the final product, including manufacturing, assembly, and packaging.
Transportation and Distribution of Finished Product (A4): This stage assesses the impacts of moving the finished product from the manufacturing facility to the end user or customer. This can many times have multiple routes.
Use Stage (Module B): The use stage evaluates the aggregate energy and/or resources that the product requires over its lifetime in order to fulfill its original intent or to be maintained. Using a laptop as an example, this stage would quantify the impacts from the energy used when plugging the laptop in to function.
End of Life (Module C): This stage assesses the impacts associated with the disposal and/or recycling of parts or all of the product at the end of its useful life.
To reiterate, the main goal of an LCA is to provide environmental impact data for the item being evaluated. This includes details such as global warming potential (GWP), emissions to the air water and soil, resource consumption, energy use, water consumption, acidification and eutrophication potential, and waste generation. The LCA also denotes impacts such as ecotoxicity and land use. These calculations are not only utilized to communicate impact, but they allow the manufacturer of the product to understand where there are areas they can focus resources to improve both effects and processes.
Now, let’s talk data. To properly model a product, material, service, or process, extensive data is required along the value chain. Using a building product LCA as an example, the LCA practitioner needs to gather two primary sources of information – supply chain and factory-level data. Ideally, practitioners should strive to gather as much primary data as possible, namely data collected directly from the source such as raw process-and site-specific data. However, many times visibility or accessibility of primary data is unclear, so supplemental data is used instead such as industry-specific databases or published reports. The practitioner also needs to understand the manufacturing process of the product so that they can develop an accurate model within multiple readily available software platforms. This model is then populated by the previously collected data to understand the impacts across the item’s life cycle.
LCA reports are then developed from these models. These tend to be very long and detailed documents that contain complex sections which explain the assumptions and calculation rules used during the actual assessment. The report also details the potential uncertainty in the results, an outcome partially based on the amount of primary vs. secondary data utilized during the evaluation. The reports many times contain the product or manufacturer’s “secret sauce”, particularly sensitive data points which may be considered proprietary information. Therefore, LCA results are typically used internally, and their external publication is communicated through an Environmental Product Declaration (EPD).
