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- Brischke, Christian, et al.
(författare)
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Natural durability of timber exposed above ground – a survey
- 2013
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Ingår i: Drvna industrija. - : Faculty of Forestry, University of Zagreb. - 0012-6772 .- 1847-1153. ; 64:2, s. 113-129
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Tidskriftsartikel (refereegranskat)abstract
- Besides its inherent resistance against degrading organisms, the durability of timber is infl uenced by design details and climatic conditions, making it difficult to treat wood durability as an absolute value. Durability classification is, therefore, based on comparing performance indicators between the timber in question and a reference timber. These relative values are grouped and related to durability classes, which can refer to a high range of service-lives. The insufficient comparability of such durability records has turned out to be a key challenge for service-life prediction. This paper reviewed literature data, based on service-life measures, not masked by a durability classification. It focused on natural durability of timber tested in the field above-ground. Additionally, results from ongoing aboveground durability studies in Europe and Australia are presented and have been used for further analysis. In total, 163 durability recordings from 31 different test sites worldwide based on ten different test methods have been considered for calculation of resistance factors. The datasets were heterogeneous in quality and quantity; the resulting resistance factors suffered from high variation. In conclusion, an open platform for scientific exchange is needed to increase the amount of available service-life related data.
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- Humar, Miha, et al.
(författare)
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Introduction of the COST FP 1303 Cooperative Performance Test
- 2015
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Ingår i: Proceedings of the 46th IRG Annual Meeting.
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Konferensbidrag (refereegranskat)abstract
- COST Action FP 1303 “Performance of bio-based building materials” successfully started in October 2013 and an ambitious program was set up for the four year programme. COST Actions provide an excellent opportunity for collaborative research, e.g. in the frame of Round Robin tests.The idea of this respective test was to distribute a fairly simple test set up to as many places in Europe as possible in order to collect performance data reflecting the range of climatic exposure conditions. Furthermore we wanted to consider performance in its manifold meaning, i.e. optical, aesthetical, moisture and functional performance and durability. In contrast to traditional Round Robin tests aiming on comparative evaluation and validation of results from different test laboratories, this initiative aims on collecting performance data under climatically different exposure conditions. Therefore it was required to provide weather data from the respective test sites to allow establishing relationships between climate conditions and the following measured, which shall be evaluated regularly: decay, discolouration, development of mould and other staining fungi, corrosion, formation of cracks and moisture performance (if data logging device is included). Further details about the test and the first outcomes are presented in this paper.
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- Jermer, Jöran, et al.
(författare)
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BESTÄNDIGHETSPROVNINGAR AV TRÄMATERIAL MED KOPPLING TILL BJÖRNLANDETS NATIONALPARK
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Durability tests of wood materials related to constructions in Björnlandet National ParkThe aim of the present study, primarily initiated by the Swedish Environmental Agency, is to study the durability of different wood materials related to and used in constructions in Björnlandet National Park in northern Sweden (63°97´N, 18°05´E), completed during 2014 and 2015. Of particular interest is to determine the durability properties in a scientific way of local materials used, such as mountain-grown Norway spruce and locally grown Scots pine and larch. The effect on the performance of charring and superficial wood-tar treatment is also studied.The study consists of a laboratory test according to ENV 807, a field trial according to EN 252 and a service trial on-site in the national park, including constructions such as load-bearing piles, ramps, foot-bridges and platforms. Results from the tests according to ENV 807 and EN 252 as well as the initial inspection of the constructions and components of different materials are presented in this report.During the initial inspection of the constructions on site, then in use for 1-2 years, no decay was found besides a small initial attack on one single pile of larch.The accelerated tests in laboratory and field have provided interesting information on the durability properties of the different materials and the ranking between them from a durability point of view which can be concluded as follows:• The local materials show moderate durability with marginal differences between the materials, with the exception of the spruce materials which show lower durability, comparable to the durability of pine sapwood.• Heartwood of locally grown pine and larch show basically equal durability properties.• Slow-grown wood will not enhance the durability properties.• Superficial treatment with wood-tar contributes so far to a somewhat increased durability. However, the primary positive effect is most certainly owing to the smell and appearance of wood treated with wood-tar, which in certain environments contributes to a positive perception. Charring does not add any value from a durability point of view.It is important that the results of the laboratory and field tests are interpreted with some care and common sense. The relatively extensive decay achieved with all materials but the preservative-treated wood does not necessarily mean that the constructions will be subject to early decay. With respect to the geographical location of Björnlandet National Park in the inland of northern Sweden, where the decay hazard in general is moderate, the local materials can thus be expected to have a reasonably long service.However, results from the tests indicate that efforts to select local materials/use "traditional" treatments most certainly will not result in longer service life than can be achieved with corresponding materials commercially available.Finally, it is pointed out that:• Avoiding moisture traps by correct design of components and constructions is vital for the service life when "traditional" local materials and treatments are used.• Preservative treatment will in general give critical wooden constructions a longer service life. The use of untreated wood involves more uncertainty with expected service life. Regular inspections and maintenance are therefore particularly important for constructions critical to personal safety (e.g. foot bridges, ramps) or infrastructure (e.g. bridges).•Urgent future objectives to complete are the inspections of the field trial until remaining stakes have been exposed for five years, and to follow up the service trial in Björnlandet National Park with inspections in 4-5 years, i.e. in 2022 or 2023 in order to confirm or reassess the preliminary conclusions.
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- Jermer, Jöran, et al.
(författare)
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Fältprovning av stängselstolpar : Lägesrapport nr 2
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This is the second progress report on two field trials with fence posts at SP’s test site in Borås, Sweden. The tests started in 1997 and 2006. The aim of the tests was to comparethe performance of posts of “traditional” materials, such as untreated, fine-textured(narrow growth rings) Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) aswell as spruce posts with charred butt end or butt end immersed in a wood tar productwith preservative-treated posts, Nordic wood preservation class NTR A.Both trials were inspected in 2016 and the conclusions reported in the first progress reportwere further confirmed, namelyPreservative-treated material, NTR class A, performs far better than untreated posts, irrespective of material, and posts of “traditional” material.Charred butt end has not improved the durability properties at all in this trial and was the same as for untreated material.The service life of the “traditional” materials was in general from a few years upto between 5 and 10 years. Favorable exposure conditions may give a somewhat longer service life.“Traditional” materials cannot be regarded as realistic alternatives topreservative-treated posts, NTR A class A, even with very low expectations onservice life and cost-effectiveness.
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