A cradle-to-gate life cycle assessment of North American wood product resin systems

Abstract

The U.S. Endowment for Forestry and Communities and the USDA Forest Service Forest Products Laboratory commissioned the Athena Sustainable Materials Institute to update four previous cradle-to-gate life cycle assessments (LCAs) of wood product resin systems (ureaformaldehyde (UF), melamine-urea-formaldehyde (MUF), phenol-formaldehyde (PF), and phenol-resorcinol-formaldehyde (PRF) as developed by Wilson 2009 [1] and develop new cradleto-gate LCAs for melamine-formaldehyde (MF), emulsion polymer isocyanate (EPI) and polymer emulsion polyurethane (PEP) wood resins. This LCA project has been conducted in accordance with ISO 14040:2006 [2], ISO 14044:2006 [3] and ISO 21930:2017 [4] and thus aligns with the most recent version of the Underwriters Laboratories Environment (ULE) Product Category Rules (PCR) for Building-Related Products and Services, Part A: Life Cycle Assessment Calculation Rules and Report Requirements [5] and Part B, North American Structural and Architectural Wood Products, Environmental Product Declaration (EPD) Requirements [6]. The study draws on confidential resin industry life cycle inventory (LCI) surveys completed for the reference year 2019. For each precursor or resin system, a minimum of three (3) and a maximum of six (6) surveys were confidentially completed by nine (9) industry participating facilities. A number of participating facilities manufacture both formaldehyde, and related resins and, where necessary, a parametrized mass allocation (PMA) approach was also developed and applied to better partition (separate) the LCI data for the production of formaldehyde (precursor) from resin production data based on updated 2019 industry process data for two formaldehyde production technologies employed by industry (Silver catalyst and Formox processes) [1]. The study also draws on updated 2020 North American upstream methanol data – the key input in formaldehyde production [1]. The LCA results were benchmarked against Wilson 2009’s previous study [1] as well as scientific literature and updated ecoinvent v3.7.1 2021 LCI datasets as a quality check. For the two-part EPI and PEP adhesives, Athena developed a generic plant model combining the manufacture of both “base” and “cross-linker” polymers for the two adhesives of interest. All resin data is presented on a 100% solids basis. To determine the data for a resin at its stated use solids percentage (e.g., UF resin at 65% solids), multiply the 100% solids data in this report by the decimal value of its stated solids use (e.g., 0.65). This report includes publicly available Annexes (A, B, and C) to document the data benchmarks with Wilson 2009 [1], ecoinvent v3.7.1 2021 LCI datasets and scientific literature, background LCI datasets used to model chemical input precursors and final resins, and sensitivity check results. A Supplementary Excel Annex is developed and presents the SimaPro LCI results for each resin on a system process basis as well as the LCA results per ISO 21930:2017 [4]. These supplementary LCA results are intended to be used by LCA practitioners in North America to develop ISO conforming wood product LCAs and EPDs.

Citation

Bushi, L.; Meil, J.; Finlayson, G. 2022. A cradle-to-gate life cycle assessment of North American wood product resin systems. Ottawa, Ontario, Canada: Athena Sustainable Materials Institute. http://www.athenasmi.org/wp-content/uploads/2022/03/Wood_Resins_LCA_Report_Final_Athena_With_CRS_Feb_2022.pdf