Harmonization of leaching tests: Leaching behaviour of wood
article
The leaching behaviour of preservative treated wood was studied, using three existing leaching methods. This study was part of a European project "Harmonization of Leaching / Extraction Tests" (EU project SMT4-CT96-2066). The leaching methods were: 1. A diffusion tank test of 3 months with medium sized samples of 200 mm length (NEN7345), 2. A laboratory protocol of 3-4 days stirring in water with small samples of about 50 mm length (ENV 1250-2), and 3. A leaching protocol of five days with large samples of one metre length (shower test). Milled wood samples were used for assessment of the total potential of leachable preservative at different pH (pH-stat test). The wood samples were taken from CCA-C treated Norway spruce and Scots pine treated with a Cu-quat. From the results it was concluded that the leaching behaviour of wood is very similar to that of other materials containing organic matter. The pH has a significant effect on leaching of preservatives from wood. The leaching behaviour of the small samples (ENV 1250-2) showed much wider variations in results. It is concluded that the NEN7345 diffusion tank test method, which was developed for inorganic building materials, is also suitable for assessment of the leaching behaviour of preservative treated wood. An adaptation of the acidic pH conditions to neutrality of the leaching water used is recommended.
Topics
TNO Identifier
280337
ISSN
00467316
Source
Heron, 46(4), pp. 239-252.
Pages
239-252