BS EN 350:2016 pdf free download

BS EN 350:2016 pdf free download.Durability of wood and wood- based products – Testing and classification of the durability to biological agents of wood and wood-based materials.
BS EN 350 gives guidance on methods for determining and classifying the durability of wood and wood-based materials against biological wood-destroying agents.
The methods can be applied either to individual wood species, batches of wood and processed wood- based materials, including heat-treated, preservative-treated wood and modified wood. However, this standard is not intended to replace testing of the efficacy of biocides.
The wood-destroying agents considered in this standard are:
— wood-decay fungi (basidiomycete and soft-rot fungi);
— beetles capable of attacking dry wood;
— termites;
— marine organisms capable of attacking wood in service.
Data on the biological durability of selected wood species considered of economic importance in European countries are presented in Annex B (informative), which also provides information relating to their geographical origin, density, sapwood width and treatability.
NOTE Treatabilfty, durability to disfiguring fungi, permeability to water and performance in use of wood and wood-based materials are also important issues. However, because standardized methods aiming to assess and classify these factors do not exist and/or have not been extensively experienced yet, preliminary guidance is given in Annex C (informative) for the classification of wood treatability with aqueous wood preservatives, Annex D (informative) for the classification of the permeability to water, Annex E (informative) for the durability to disfiguring fungi, and Annex F (informative) for the classification of performance.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
4 Sampling of wood and wood-based materials to be tested
4.1 Testing wood species
4.1.1 General
The origin of test specimens and the number of replicates is of great importance for the reliability of the test results.
The reliability of conclusions relating to the durability of a wood species increases with the number and diversity of growing sites from which trees are taken and the number of replicates from those trees. The recommendations given in 4.1.2 to 4.1.3 shall be regarded as minima.
NOTE Background information on sampling can be found in ISO 2859-2 and ISO 3129.
4.1.2 Sampling logs
A log shall be taken from at least 3 trees of the species under test, originating from 3 different sites representative of the diversity of the geographical regions or sites where the tree species grows. Samples should be taken from at least 5 planks, originating from at least 3 trees when only sawn wood is available (see Annex A).
If high between-tree variation is expected (e.g. different botanic species), it’s recommended to test a larger number of trees (e.g. 5 — 10).
NOTE 1 It can be useful to test in parallel material derived from wood species with known durability.
Each log shall be of sufficient size to permit the required number of test specimens to be obtained from
Each log shall be taken from the main trunk avoiding its extreme ends. Knots and other features which can influence durability shall be avoided.
Sampling shall consider sapwood. heartwood and juvenile wood separately. While testing heartwood, the region within at least 3 cm of the pith shall be excluded in order to avoid juvenile wood, which is often less resistant than the mature heartwood. For heartwood sampling, both the inner (closest to the pith) and the outer (closest to the sapwood and thus including transition wood) parts of the heartwood shall be incorporated.
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.6 Test methods and classification system
NOTE Annex G provides a template form presenting the information which is required for adding new data to the standard.
6.1 Durability to wood-destroying fungi
6.1.1 General
Durability to a well-defined set of wood-destroying fungi can be assessed by performing laboratory tests (6.1.2.1 and 6.1.2.2).
NOTE Field tests allow determining the durability of a wood species or a wood-based material in different end-uses (above-ground, in-ground) and expose it to a wider range of wood colonising and destroying organisms and long term conditioning through exposure to weather. Laboratory tests are more specific as they are performed under fully controlled conditions.BS EN 350 pdf download.