BS EN 350:2016 pdf download.Durability of wood and wood- based products — Testing and classification of the durability to biological agents of wood and wood-based materials.
4.1.3 Sampling sawn timber Wood placed on the market is mostly available as sawn timber and hence it is difficult to identify pieces originating from specific trees. For this reason, it is preferred to sample as many pieces as possible so as to better estimate the overall durability. A minimum of 30 pieces originating from minimum 5 batches and providing 1 specimen per piece is required. The general considerations described in 4.1.2 related to sampling also apply for sawn wood.
4.2 Testing of sets of wood Since timbers are mostly presented on the market as commercial supplies there is a need to assess their durability. A maximum of wood pieces shall be used for the realization of the test specimens (e.g. 2 replicate test specimens from each of 20 pieces are preferred to 10 specimens from each of 4 pieces). To give a good indication on the variability of the tested set of wood, it is recommended to test at least 30 specimens per variable (for example “test method” or “test organism”).
4.3 Testing of wood-based materials The sampling should take into account the variability of the wood-based material to be tested. For each variation in processing parameter (e.g. a change in temperature, particle size, wood species), a minimum of 30 specimens is required, derived from at least 3 produced items (e.g. boards) sampled at random from 3 different batches. A minimum of 5 specimens from each batch should be tested. If the material contains both sapwood and heartwood, care has to be taken that both sapwood and heartwood are used to produce the test specimens.
5 General principles for testing and classification 5.1 General principles for testing wood specimens When testing a wood species, an identification of the tree or the wood species shall be done. Wood species shall be specified according to EN 13556. In order to get a homogeneous set of samples in terms of moisture content, the test specimens shall be conditioned prior to testing in a ventilated conditioning chamber at controlled temperature and relative humidity, until their weight and moisture content are stabilized. The sample selection requirement for reference specimens shall follow the instructions of the relevant test method. If several wood species are tested at the same time, one set of reference specimens is sufficient. Test timber used to determine the durability of a wood species should not be oven-dried at temperatures above 60 °C prior to the test. If laboratory test vessels are used, reference specimens and test specimens shall be tested in separate vessels. EN 73 or EN 84 are ageing procedures which might be required prior to biological testing.BS EN 350 pdf download.