BS/EN 113-2-2020 pdf download.Durability of wood and wood-based products — Test method against wood destroying basidiomycetes Part 2: Assessment of inherent or enhanced durability.
direction. Transverse cuts shall be made neatly to give sharp edges and a line-sawn finish to the end- grain surfaces, to give timber test specimens (50 ± 0,5) mm long.
The test specimens shall originate from a minimum of three trees or shall be taken at random from a stock originally of more than 500 test specimens and originating from at least five planks. Concerning modified wood the test specimens should be taken from three hatches or manufacturing lots.
6.4 Dimensions of test specimens
The dimensions of each timber test specimen measured at (12 ± 2) % moisture content or conditioned at
(65 ± 5) % RH (relative humidity) and (20 ± 2) °C for at least 2 weeks, shall be
(50 ± 0,5) mm x (25 ± 0,5) mm x (15 ± 0,5) mm.
NOTE I A two-prong electrical conductivity moisture meter is suitable for assessing moisture content.
NOTE 2 The nominal volume of each test specimen Is 18.75 cm3.
The dimensions of at least 10 specimens should be controlled randomly. If they are within the required specifications, it is not necessary to measure the whole batch. If one of the controlled specimen does not fulfil the requirement all specimens in the batch should be measured.
6.5 Number and distribution of test specimens
The timber test specimens are provided as:
— e1 Test specimens:
These are the test specimens of the test timber subjected to attack by the wood-destroying basidiomycete fungi. Use at least 30 test specimens for exposure to each test fungus. Specimens should be obtained from a minimum of live logs or five planks (mainly for testing natural durability of a wood species) or if relevant from at least 3 batches or manufacturing lots (mainly relevant for modified wood) and the sampling should take into account information provided in Annex A.
Mark each test specimen so that it can be identified throughout the test.
Materials under test that allow for ovendrying prior to testing do not require to include an additional set of specimens related to moisture content. When assessing natural durability or modifed wood it is necessary to avoid the impact of ovendrying at (103 ± 2) °C prior to testing and hence an additional set of specimens is required: moisture content test specimens. For some modified material it can also be necessary to avoid the impact of ovendrying.
— e2 Moisture content test specimens:
The durability classes should be based on the degradation of the wood component of the material under test. A correction might be needed to the masses considered e.g. when the wood material was treated at high resin content.
7 Procedure
7.1 Preparation of the wood test specimens
7.1.1 Virulence control
Place the numbered reference wood test specimens in the oven (5.3.2) and leave them for 18 h to 24 h. Cool to room temperature in a desiccator (5.3.3) and weigh to the nearest 0,01 g to determine the initial dry mass (m0). Place the test specimens in the conditioning chamber (5.3.4) until they need to be sterilized.
7.1.2 Wood under test
If the test specimens are to be subjected to an ageing procedure, the procedure should be carried out prior to conditioning to constant mass to avoid the need to establish changes in mass due to the ageing procedure.
Place the numbered wood test specimens (e1) and the moisture content test specimens (e2) in the conditioning chamber (5.3.4) until weighings of sample test specimens at 24 h intervals are within ± 0,01 g. Weigh the wood test specimens and the moisture content test specimens and record the initial conditioned mass (m1).
Calculate the mean density of the wood test specimens using the mean conditioned mass and the nominal volume (see 6.4).
Option A: For test materials that cannot be ovendried prior to fungal test (e.g. untreated wood, modified wood that can be altered by the drying).
Place the moisture content test specimens in the oven (5.3.2) and leave them there for 18 h to 24 h. Cool to room temperature in a desiccator (5.3.3) and weigh to the nearest 0,01 g to determine the oven dry mass (m0).
Calculate the moisture content of each moisture content test specimen by expressing the mass of water (rnj . m0) as a percentage of the oven dry mass (m0).
Calculate the mean moisture content (MC) of the moisture content test specimens. Use the mean moisture content to calculate the theoretical initial dry mass (mi) of each wood test specimen using the equation:BS/EN 113-2-2020 pdf download.