Service life prediction of wooden components – Part 1: Determination of dose-response functions for above ground decay
C Brischke, A O Rapp
Scots pine sapwood (Pinus sylvestris L.) and Douglas fir heartwood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 24 different European test sites under different exposure conditions (in total 28 test sets). The material climate in terms of wood moisture content (MC) and wood temperature was automatically recorded over a period of up to eight years and compared with the progress of decay. The final results of the study are presented within this paper. Significant differences among the test sites were observed regarding the time lag between the start of exposure and the onset of decay as well as the progress of decay. The overall aim of this study was to establish dose-response relationships between climate factors and decay as a basis for service life prediction of wooden components. The use of the combined material climatic parameters MC and wood temperature led to a feasible dose-response function and turned out to be a useful basis for service life prediction. How to apply this approach for estimating the expected lifetime of wooden components under various exposure conditions will be shown in part 2 of this series.
Keywords: double layer test, dose-time function, field test, material climate, test site, wood moisture content, wood temperature