1、BS EN 350:2016Durability of wood and wood-based products Testing andclassification of the durabilityto biological agents of woodand wood-based materialsBSI Standards PublicationBS EN 350:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of beetles capable of attack
2、ing 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 ori
3、gin, density, sapwood width and treatability. NOTE Treatability, 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 an
4、d/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 d
5、isfiguring 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 und
6、ated references, the latest edition of the referenced document (including any amendments) applies. EN 20-1, Wood preservatives - Determination of the protective effectiveness against Lyctus Brunneus (Stephens) - Part 1: Application by surface treatment (laboratory method) EN 46g9391, Wood preservati
7、ves - Determination of the preventive action against recently hatched larvae of Hylotrupes bajulus (Linnaeus) - Part 1: Application by surface treatment (laboratory method) EN 49-1, Wood preservatives - Determination of the protective effectiveness against Anobium punctatum (De Geer) by egg-laying a
8、nd larval survival - Part 1: Application by surface treatment (Laboratory method) EN 117, Wood preservatives - Determination of toxic values against Reticulitermes species (European termites) (Laboratory method) EN 252, Field test method for determining the relative protective effectiveness of a woo
9、d preservative in ground contact EN 275, Wood preservatives - Determination of the protective effectiveness against marine borers ENV 12038, Durability of wood and wood-based products - Wood-based panels - Method of test for determining the resistance against wood-destroying basidiomycetes BS EN 350
10、:2016g8g17g3g885g887g882g483g884g882g883g888g3g525g8g5265BS EN 350:2016EN 350:2016 (E) 6 EN 13556, Round and sawn timber - Nomenclature of timbers used in Europe CEN/TS 15083-1, Durability of wood and wood-based products - Determination of the natural durability of solid wood against wood-destroying
11、 fungi, test methods - Part 1: Basidiomycetes CEN/TS 15083-2, Durability of wood and wood-based products - Determination of the natural durability of solid wood against wood-destroying fungi, test methods - Part 2: Soft rotting micro-fungi EN 16449, Wood and wood-based products - Calculation of the
12、biogenic carbon content of wood and conversion to carbon dioxide ISO 13061-2, Physical and mechanical properties of wood Test methods for small clear wood specimens Part 2: Determination of density for physical and mechanical tests 3 Terms and definitions For the purposes of this document, the follo
13、wing terms and definitions apply. 3.1 wood species trade name according to EN 13556 which can on occasion include more than one botanical tree species Note 1 to entry: E.g. European oak which comprises both Quercus robur and Q. petraea. 3.2 pilot name for a wood species result of a consensual choice
14、 due to practical considerations retaining the usual name under which the wood is the most widely commercialised, adopted either by the main exporting country or by the main importing country Note 1 to entry: Pilot names are established since 1954 in the nomenclature of the ATIBT. 3.3 set clearly id
15、entifiable collection of units of wood or wood-based products, originating from a commercial supply of a defined origin (single or not) and likely comprising only some of the variability of the wood species or of the wood-based material Note 1 to entry: E.g. wood species sourced from a restricted ge
16、ographical area. 3.4 wood-based material any processed matrix containing and/or made of a specific percentage of wood Note 1 to entry: Wood-based materials are those derived from trees and include amongst others heat-treated wood and any other material modified by chemical, physico-chemical or physi
17、cal process, glue-laminated wood, wood-based panels, wood polymer composites and treated with wood preservatives. This standard is not meant to test all ligno-cellulosic materials (e.g. bamboo, reed, straw, flax) as such and would require methodological adaptions to do so. BS EN 350:2016g8g17g3g885g
18、887g882g483g884g882g883g888g3g525g8g5266BS EN 350:2016EN 350:2016 (E) 7 3.5 modified wood wood that undergoes the action of a chemical, biological or physical agent, resulting in a permanent desired property enhancement Note1 to entry: If the modification is intended for improved resistance to biolo
19、gical attack, then the mode of action is assumed to be non-biocidal. 3.6 durability to biological agents inherent resistance of a wood species or a wood-based material against wood decay organisms Note 1 to entry: This inherent resistance is due to the presence of natural components that can exhibit
20、 different levels of toxicity towards biological organisms and/or to anatomical particularities or a specific constitution of certain wood-based materials. 3.7 sapwood outer zone of wood that, in the growing tree, contains living cells and conducts sap Note 1 to entry: Depending on the species, age
21、of the tree and the growing conditions the proportions of sapwood and heartwood can vary. Note 2 to entry: Frequently paler than heartwood though not always distinguishable from heartwood in some wood species. Note 3 to entry: Sapwood of all wood species is considered to be non-resistant against dec
22、ay fungi unless other data are available. Sapwood can have different levels of resistance against wood boring insects (excluding termites). 3.8 heartwood inner zone of wood that, in the growing tree, has ceased to contain living cells or to conduct sap Note 1 to entry: Frequently darker than sapwood
23、 though not always distinguishable from sapwood in some wood species. 3.9 transition wood wood in a zone between the sapwood and the heartwood Note 1 to entry: The transition wood can be regarded as a region of the heartwood that has not fully matured. This is only distinguishable in very few wood s
24、pecies. In general, its biological durability, treatability and permeability to water is intermediate between that of sapwood and heartwood. 3.10 juvenile wood set of few growth rings of woody tissue nearest the centre of the tree, often having abnormal properties Note 1 to entry: Juvenile wood is a
25、 zone near to the pith, displaying marked ring to ring changes in its properties. There is no clear consensus as to where this zone ends. It is generally thought to end at 10 to 20 rings from the pith, but it depends on the wood species. Note 2 to entry: The durability, permeability to water and tre
26、atability of juvenile wood can be different from that of mature heartwood. BS EN 350:2016g8g17g3g885g887g882g483g884g882g883g888g3g525g8g5267BS EN 350:2016EN 350:2016 (E) 8 3.11 permeability to water ease with which water penetrates a wood-based matrix (wood of a particular species, wood-based mater
27、ial) and is released by evaporation 3.12 performance ability of a wood species or a wood-based material to withstand deterioration over time 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
28、 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
29、 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 reg
30、ions 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), its recommended to test a larger number of trees
31、(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 it. Each log shall be taken from the main trunk avoiding its extreme ends. Knots
32、 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
33、 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. NOTE 2 For some species, in order to better assess the variability, there can be a need to sample th
34、e transition wood and juvenile wood separately. For logs of large diameter, a larger number of samples shall be taken from the outer part (outer third of the heartwood radius which is closest to the sapwood). For each part of the wood (heartwood, transition wood, sapwood, juvenile wood) to be tested
35、, at least 30 test specimens shall be taken for each test variable (for example “test method” or “test organism”). A minimum of 6 specimens shall be taken from each log. BS EN 350:2016g8g17g3g885g887g882g483g884g882g883g888g3g525g8g5268BS EN 350:2016EN 350:2016 (E) 9 Depending on the selected test m
36、ethod, additional specimens might be required to determine the density of the wood species and the moisture content of the specimens. The sampling shall be done according to the relevant standards (ISO 13061-2 for density and ISO 13061-1 for moisture content). NOTE 3 A scheme of a suitable preparati
37、on and distribution of the specimens for testing is showed in Annex A. 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 po
38、ssible 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
39、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 g
40、ood 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.
41、 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.
42、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 th
43、e 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 rela
44、tive 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 us
45、ed 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
46、to biological testing. The properties of the test specimen shall, as far as possible, be representative for the wood species being tested even if this does not follow the instruction given on sample selection in the relevant test BS EN 350:2016g8g17g3g885g887g882g483g884g882g883g888g3g525g8g5269BS E
47、N 350:2016EN 350:2016 (E) 10 standard. However, the results still cannot be expected to take into account the full range of variation of properties within a species. EXAMPLE 1: If the test method excludes the use of “wood of resinous appearance”, but the species to be tested normally has a naturally
48、 resinous appearance, this exclusion is ignored. EXAMPLE 2: If the test method requires a certain number of growth rings per centimetre, this restriction is ignored if growth rings do not exist or are too widely spaced. This is of importance for some tropical timbers, because it is sometimes impossi
49、ble to see the growth rings; the rings can also correspond not to the annual growth but to the alternation of dry and wet seasons. 5.2 General principles for the classification of durability The durability of a wood species or a wood-based material to various wood destroying organisms is tested using methods described in relevant European Standards. The use of replicate specimens is a requirement in all test methods. For wood species, durability classes refer only to heartwood. Sapwood is always regarded as not durable, unless test data provide different information. Based on
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