IVL Svenska Miljöinstitutet

The use of chemicals in construction products and risk mitigation is an area that is often attached to the selection of the material. Wood preservatives are used to increase the durability of the wood so that it can be applied in fields that otherwise would not have been possible. The use of wood preservatives is regulated in the Biocides Directive and requires a national approval from the Swedish Chemicals Agency (for the Swedish market). A life cycle assessment (LCA) on pressure treated pine according to NTR class A with a copper based agent was implemented in the project. The analysed product category in the case study is fence posts including pressure treated timber and alternative posts of; plastic, untreated wooden posts of robinia (from central Europe) and Siberian larch (from Siberia). The report reflects Swedish or Scandinavian conditions. In the assessment, the LCA methodology and the environmental impact indicators used, as prescribed by the general Product Category Rules (PCR) for construction products (EN 15804). This so-called Core PCR is linked to the European construction products directive (CPR). The purpose of this study is to evaluate how these policies can be used and to analyse the environmental performance with respect to selected and mandatory impact indicators in the environmental product declaration (EPD). Calculations found that NTR Class A treated pine has a better environmental performance in comparison with the alternative materials used for the assessment. Uncertainties in the choice of service life prediction data exist in relation to plastic posts, but also to some extent to posts of robinia and larch. These differences determine the relative ranking for other options. The study has taken into account all environmental impact categories, which are required to be included in accordance with EN 15804 apart from resource use, since assessment methods for resource use lack factors for renewable materials. This impact category has therefore been excluded from the study, as it else would render a comparison incomplete with respect to the plastic alternative. Thus we find a need to develop better methods to assess resource use in the future. Since human toxicity and ecotoxicity are not found among the mandatory environmental impact categories included in the LCA, in accordance with EN 15804, these aspects are not included in the assessment, and even here we find a need of future developments.

This report is also available in Swedish.