BS EN 84-2020 Durability of wood and wood-based products – Accelerated ageing of treated wood prior to biological testing一Leaching procedure

BS EN 84-2020 Durability of wood and wood-based products – Accelerated ageing of treated wood prior to biological testing – Leaching procedure. 6 Test specimens 6.1 Definition and origin The test specimens and their preparation are defined in the standards concerning the biological tests to which they are intended to be subjected. The leaching procedure shall be carried out after the end of the preparation of test specimens for testing described in the relevant biological test standard. This includes any treatment and subsequent conditioning period where relevant. 6.2 Number of test specimens The number of test specimens shall allow the relevant biological tests to be carried out in accordance with the instructions in the appropriate standards, bearing in mind that in some tests the leaching procedure shall be applied to control specimens as well as to test specimens. The control specimens may be of the following kinds where required by the relevant test standard: — check test specimens that will not be subjected to attack by biological agents after the leaching procedure. These will serve as controls for changes in mass in those tests in which this factor is taken into consideration; — untreated control or reference species specimens which, after leaching, are subjected to the test by biological agents to check any variation in the behaviour of the reference species. 7 Procedure 7.1 Leaching 7.1.1 Impregnation with water Place the test specimens in the test vessels (see 5.2.2). Do not place in the same vessel test specimens of different species, specimens treated with different products or with different concentrations or loadings of the same product, specimens from wood modified using different processes or to different extents, or both test and control specimens. Ballast them with weights (see 5.2.5) to prevent them from floating. Pour sufficient water (see 5.1) into the test vessels to cover the groups of test specimens and to ensure that the test specimens remain covered throughout the impregnation. Place the test vessels In the vacuum desiccator (see 5.2.3); establish a vacuum corresponding to a pressure of 4 kPa and maintain this fora minimum of 20 mm before release. Leave the test specimens in the vessels for minimum 2 h. Empty the water from the vessels.BS EN 84 pdf download.