Life cycle assessment of oriented strand boards (OSB): from process innovation to ecodesign

Oriented strand boards (OSBs) are wood panels that are used worldwide mainly in the packaging and the building sectors. Their market share is rapidly increasing thanks to their outstanding mechanical properties and to a renewed interest for wood based products. The OSB production process generates, nonetheless, emissions of volatile organic compounds (VOCs) during the air-drying of wood strands. This known problem in the literature leads to an odorous nuisance in the surrounding area of the production site. In order to address this problem, a novel application to wood drying of an innovative vapor drying technology is successfully operated at the production site of Kronospan Luxembourg S.A. In addition to the reduced odorous nuisance, a significant environmental added value is expected because of the other modifications induced by the vapor-drying technique on the OSB production process viz. the reduced energy and raw materials demands and the change of adhesive mixture, with the addition of phenol resin. The potential impact of this technology on the OSB market is therefore very significant. This study was aimed at assessing the environmental added value provided by the vapor-drying technique through a life cycle assessment (LCA) according to ISO 14040-44 standards. The objective was to compare the environmental performances of the former and the current OSB production processes. Considering only the pollutant emissions from the OSB production process, the reduction of climate change impact and human health damage is significant respectively, 15-20% and 50-75%. When the lifecycle processes related to the OSB production are included, the reduction of damages does not exceed 3-7%. Following an uncertainty analysis,this reduction was nevertheless proven to be statistically significant. However, it is observed that the reduction of environmental impacts and damages allowed by the vapor-drying technology is counterbalanced by the change of adhesive mixture. Indeed the new adhesive mixture generates higher environmental damages than the former mixture because of the higher energy and raw material demand from phenol resin production. These results show the need to move from an approach focused on a single process innovation (the vapor-drying technique) to a more general and systemic approach combining process and product ecodesign. Such approaches are needed in order to effectively improve the overall environmental performance of a production system, without transfer of pollution along the lifecycle or offsets of pollution credits. LCA is definitively one of the most pertinent tools to identify improvement opportunities in the comparison of alternative designs from an environmental perspective.