Environmental assessment and improvement alternatives of a ventilated wooden wall from LCA and DfE perspective

PURPOSE: The main goal of this paper was to analyse the environmental profile of a structural component of a wooden house: a ventilated wooden wall, by combining two environmental methodologies: one quantitative, the life cycle assessment (LCA) and another qualitative, the design for the environment (DfE). METHODS: The LCA study covers the whole life cycle of the ventilated wall manufacture as well as its distribution, installation and maintenance. To carry out this analysis, a Galician wood company was assessed in detail, dividing the process into four stages: the assembling stage, the packing stage, the distribution to clients as well as the final installation and maintenance of the wooden wall. Ten impact categories have been assessed in detail in the LCA study: abiotic depletion (AD), acidification (AC), eutrophication (EP), global warming (GW), ozone layer depletion (OD), human toxicity (HT), fresh water aquatic ecotoxicity (FE), marine aquatic ecotoxicity (ME), terrestrial ecotoxicity (TE) and photochemical oxidant formation (PO). RESULTS AND DISCUSSION: According to the environmental results, the assembling stage was the most important contributor to the environmental profile with contributions from 57% to 87%, followed by the production of the electricity required. The detailed analysis of the assembling stage identified the most important environmental hot spots: the production of boards used in the structure [oriented strand board and medium density fibreboard (MDF)] as well as the transportation of the cedar sheets from Brazil. Concerning the results of the DfE, a selection of different eco-design strategies was proposed from technological, economic and social points of view by an interdisciplinary team of researchers and company´s workers. The eco-design strategy considered the following improvement actions: (i) the substitution of the MDF in the wall structure; (ii) the use of German red pine sheets; (iii) the installation of solar panels in the facilities; (iv) the use of Euro 5 transport vehicles, (v) the use of biodiesel for transport; (vi) the definition of a maintenance protocol for the wooden materials; and (vii) the definition of a protocol for the separation of materials before disposal. CONCLUSIONS: The results obtained in this work allow predicting the influence of the selection and origin of the raw materials used on the environmental burdens associated with the process. Future work will focus on the manufacturing of a prototype of