How can a life cycle inventory parametric model streamline life cycle assessment in the wooden pallet sector?

Purpose: This study discusses the use of parameterization within the life cycle inventory (LCI) in the wooden pallet sector, in order to test the effectiveness of LCI parametric models to calculate the environmental impacts of similar products. Starting from a single case study, the objectives of this paper are (1) to develop a LCI parametric model adaptable to a range of wooden pallets, (2) to test this model with a reference product (non-reversible pallet with four-way blocks) and (3) to determine numerical correlations between the environmental impacts and the most significant LCI parameters; these correlations can be used to improve the design of new wooden pallets. Methods: The conceptual scheme for defining the model is based on ISO14040-44 standards. First of all, the product system was defined identifying the life cycle of a generic wood pallet, as well as its life cycle stages. A list of independent and dependent parameters was used to describe the LCI flows of a generic wooden pallet. The LCI parametric model was applied to calculate the environmental impacts of the reference product, with regard to a selection of impact categories at midpoint level (climate change, human toxicity, particulate matter formation, agricultural land occupation, fossil depletion). The model was then applied to further 11 wooden pallets belonging to the same category. Results and discussion: The definition of a LCI parametric model based on 31 independent parameters and 21 dependent parameters streamlined the data collection process, as the information required for fulfilling the LCI are standard information about the features of the wooden pallet and its manufacturing process. The contribution analysis on the reference product revealed that the most contributing life cycle stages are wood and nails extraction and manufacturing (positive value of environmental impact) and end-of-life (avoided impact). This result is driven by two parameters: mass of wood and average distance for transport of wood. Based on the results of the application of the LCI parametric model to the identified products, one parameter-based regression and one multiple non-linear regression allowed to define a correlation between the life cycle impact assessment (LCIA) category indicators considered and the most influencing parameters. Conclusions: The definition of LCI parametric model in the wooden pallet sector can effectively be used for calculating the environmental impacts of products with different designs, as well as for obtaining a preliminary estimation of the life cycle environmental impacts of new products.