EN 20-2-1993 pdf download

07-20-2021 comment

EN 20-2-1993 pdf download.Wood preservatives — Determination of the protective effectiveness against Lyctus brunneus (Stephens) — Part 2: Application by impregnation (laboratory method).
7 Test specimens
7.1 Species of wood
The test shall be carried out on European oak. This shall comprise sessile oak, Quercus pet raea (Mattuschka) Lieblin. andlor pedunculate oak, Quercus robur Linnaeus.
7.2 Quality of wood
Use only sound sapwood with between 2 annual growth rings per 10 mm and 10 annual growth rings per 10 mm, straight-grained without knots. The wood, having few tyloses, shall not have been floated or subjected to any chemical treatment and shall be dried without delay as described in 7.3.
7.3 Provision of the test specimens Remove the bark from the freshly cut billets and then cut them into lengths (from which strips 25 mm x 15 mm in cross section will be cut). Immediately place the billets in the drying chamber (5.3.3) stacked with spaces between individual billets so as to allow movement of air through the stack. Retain the billets in the drying chamber until their moisture contents are reduced to 15% (rn/rn).
NOTE Moisture contents may be assessed in accordance with iSO 3130. In addition moisture meters of the two•pronged electrical conductivity type are also suitable.
Cut the sapwood of the dried billets into planed strips 25 mm x 15 mm cross section and with the wide longitudinal faces oriented tangentially. Cut the specimens for test from the planed strips. The individual specimens for test shall be cut cleanly and shall have sharp edges.
The specimens required for a test shall be taken from at least two lots, each corresponding to a different tree or two sapwood strips taken from diametrically opposed positions in the same log. The specimens from the two sources shall be combined and the test specimens taken at random from them.
7.4 Dimensions of test specimens
The dimensions of each specimen after one week in the conditioning chamber (5.3.2) shall be:
(50±0,5) mm X(25±0,5) mm X(15±O,5) mm For the purpose of calculating the mass of preservative retained per unit volume of wood (8.3.2) the nominal volume of each test specimen shall he taken as 18,75 cm3.
Mark each specimen so that it can be identified throughout the test.
7.5 Number of test specimens
Use:
a) for each preservative and each concentration:
five specimens (see 7.4):
b) for a complete test of any given preservative:
five untreated control specimens (see 7.4);
c) if a solvent or diluent is used: five control specimens (7.4) t.reated with that. solvent or diluent (5.2.4 or 5.2.5).
8 Procedure
8.1 Prior impregnation of the test specimens with a nutrient solution
8.1.1 Composition of the nutrient solution I)issolve 2 g of peptone (5.2.6) and 10 g of the glucose (5.2.7) in 100 ml water (5.2.4).
8.1.2 Method of impregnation of nutrient solution
Weigh each test specimen, place them in a beaker and ballast them with weights (5.3.9) to prevent them floating. Place the beaker in the vacuum vessel (5.3.7), and reduce the pressure using the vacuum pump (5.3.8) to 700 Pa. Hold the specimens at this pressure for 15 mm. Allow the nutrient solution (8.1.1) into the beaker so as to cover the specimens. Bring the specimens back to atmospheric pressure, adding further solution if necessary to keep the specimens covered.
Leave the specimens immersed for 1 h in the solution and then reweigh them after draining for 1 mm.
Determine the uptake of nutrient solution for each test specimen.
Retain for testing only test specimens absorbing between 300 kg/rn3 and 600 kg/rn3 of nutrient solution.
8.1.3 Drying of test specimens
Dry the specimens in the drying chamber (5.3.3) at (30 ± 2) °C for one week.
8.2 Conditioning of specimens before treatment
Transfer the dried test specimens to the conditioning chamber (5.3.2) and condition them for one week.
8.3 Treatment of the test specimens
8.3.1 Preparation of treatment solutions
8.3.1.1 Solid preservatives
Dissolve the preservative in an appropriate solvent (5.2.5) to the required concentration, or to a series of concentrations if toxic values are to be determined.EN 20-2-1993 pdf download.

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