Life Cycle Assessments aim to understand the impacts of products, services, and organizations over the entire life cycle, from manufacture and disposal. Still, even when a LCA does model impacts from cradle-to-grave, there still can be deviances from what is included from one study to the next. As part of the goal and scope of the LCA, the LCA practitioner outlines what will be included in the assessment and what will not. This description is the system boundary – all processes within the system boundary are modeled as part of the product’s impacts and all processes outside the system boundary are not included in the LCA model.
Ecosystem Analytics LCA on reusable handkerchiefs versus disposable facial tissues, like most LCAs, covers the production, transport to retail, use, and disposal of the products and retail packaging. Transportation between production steps, packaging used to assist shipping between production steps, and disposal of waste products and packaging used during production are included in the LCA as part of the product’s manufacturing.
Like most LCAs, there are some processes outside of the system boundary for this LCA. Transportation from retail to the user’s residence and transportation from the user’s residence to the location of final disposal was not included in the model, given the small size/weight fraction of the products relative to the overall shopping trip or garbage bag and that the transportation lengths can vary greatly. Likewise, the impacts of building capital equipment such as washing machines, drying machines, paper plants, textile production plants are not included in the LCA. Since the functional unit only covers 1 year of use, handkerchief disposal is not modeled as part of the functional unit due to the longer useful life of the handkerchief. In future posts, we will explore this as part of sensitivity analysis.
To explore what is included in one stage of the LCA, let’s looks at the use phase. Facial tissue use is fairly simple – only the paper facial tissues are used. Handkerchief use also involves the washing of the handkerchief, requiring the modeling of the impacts of use of tap water, detergent, detergent packaging, energy for the washer and dryer, wastewater treatment, and disposal of detergent packaging.
We have previously described how the functional unit is calculated, the reference unit for the study. In the next post, we will describe how each product used throughout the life cycle is included in LCA modeling.
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