The wood in 3rd and 4th use class is endangered by numerous abiotic and biotic degradation factors. These processes are essential for natural carbon cycle, but when the wood is used for economic purposes, these processes of decomposition are undesired, thus we would like to slow them down as much as possible. One of the solutions for this is impregnation with copper-ethanolamine preservatives. There were quite some studies performed on conifer wood, but there are no reports for the hardwoods, particularly ring porous ones. Therefore, we have made samples from ring porous hardwoods, impregnated them with 2 concentrations of preservative solution Silvanolin. The samples were leached out according to the CEN/TS 15119-2:2008 and CEN/TS 15119-1:2008 standards. The first one is designed for leaching of wood in use class 4 and 5, the second for leaching of active ingredients from wood in use class 3 applications. The moisture content of wood and pH value of leachates were determined. Spectroscopy XRF was applied in order to determine the Cu concentration in leachates. During the leaching, the moisture content increased much higher in the samples leached according to use class 4 and 5 procedure than those leached in class 3 procedure. Additionally lower pH values of leachates were determined, due to extractives. The results show that the concentration of active ingredients did not have a distinctive influence on penetration. The lowest penetration was determined at samples made of robinia. At samples made of oak and sweet chestnut the penetration was slightly better, but due to the limited fixation sites in wood, significant percentage of retained active ingredients were leached from wood. The leaching according to the standard CEN/TS 15119-2:2008 was much more intensive then that according to the standard CEN/TS 15119-1:2008.
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