BS EN 84-2020 pdf free download.Durability of wood and wood-based products — Accelerated ageing of treated wood prior to biological testing — Leaching procedure
This document specifies a method for leaching, applicable to test specimens of wood or wood-based products which are subsequently subjected to biological tests.
This document is applicable to:
a) the pre-conditioning of test specimens prior to their being subjected to a biological test; or b) assessment of loss of effectiveness by comparing the performance in a biological test of treated test specimens subjected to this procedure with others that have not undergone any leaching procedure.
NOTE The method can also be used for pre-conditioning of untreated wood, modified wood and wood-based panel products, whether they received preservative treatment or not.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp/ui
• IEC Electropedia: available at http://www.electropedia.org/
4 Principle
Impregnation with water under vacuum, followed by immersion in water for a specified period, of test specimens that have been prepared for biological testing against fungi or insects, using the appropriate standard methods.
5 Material and apparatus
5.1 Material
Water, complying with grade 3 of EN ISO 3696.
5.2 Apparatus
5.2.1 Conditioning chamber controlled at a temperature of (20 ± 2) °C and (65 ± 5) % relative humidity for conditioning the test specimens.
5.2.2 Test vessels of material that does not react with the preservative product under test:
— either of glass, especially for the organic solvent products;
— or of plastic materials for products that are likely to attack glass.
The capacity of the test vessels shall be such that they can contain, in addition to the test specimens, the volume of water specified in 7.1.2.
5.2.3 Vacuum desiccator, fitted with a stopcock.
5.2.4 Vacuum pump fitted with a pressure gauge and capable of maintaining a pressure of minimum 4 kPa.
5.2.5 Weights, of a material which does not react with the treated blocks, water or the test vessel, for ballasting the test specimens.
5.2.6 Ordinary laboratory equipment.
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 for a minimum of 20 min before release.
Leave the test specimens in the vessels for minimum 2 h.
Empty the water from the vessels.BS EN 84 pdf download.