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Evaluation of fungal infestation and decay in a simulated use class 3 situation (block test) after some years of exposure
2012 - IRG/WP 12-20487
The so named “block test” was designed as part of the assessment methodology for testing the behaviour of natural and modified wood used under use class 3 (EN 335-2) conditions. The test was developed to expose the wood close to the ground to an environment with high humidity and high biological activity, but not in soil contact. The present study describes the evaluation of fungal infestatio...
A Gellerich, K Röhl, S Adamopoulos, H Militz


Analyses of premature failure of utility poles
2012 - IRG/WP 12-40584
In this study a total number of 18 utility poles of Scots pine (Pinus sylvestris) impregnated with a copper-chromium containing preservative were investigated. They were part of different lower voltage transmission lines in the western part of Germany and failed before predicted minimum service life. All poles in this study were less than 15 years in use. The type of decay and fungi were evaluated...
S Bollmus, N Rangno, H Militz, A Gellerich


Statistical analysis of durability tests - Part 1: Principles of distribution fitting and application on laboratory tests
2013 - IRG/WP 13-20504
Service life prediction is an important topic in wood research, especially with regard to the Construction Products Regulation (CPR). Both laboratory tests as well as in-service performance testing are therefore essential in combination with proper monitoring and analysis tools. A crucial concept is variability in testing and analysis, especially for a biological material such as wood. The larger ...
I De Windt, J Van den Bulcke, C Brischke, C R Welzbacher, A Gellerich, S Bollmus, M Humar,


Determination of the natural durability of solid wood against wood-destroying fungi - a European round-robin test
2013 - IRG/WP 13-20511
In Europe the durability of wood against wood-destroying basidiomycetes is tested according to CEN/TS 15083-1 (2005). Hitherto existing experience with this standard is quite heterogeneous and results from previous round-robin tests have stayed unreported or have been reported incompletely. In particular the need for natural pre-weathering of the test specimens to allow potential detoxification of...
C Brischke, C R Welzbacher, A Gellerich, S Bollmus, M Humar, K Plaschkies, W Scheiding, G Alfredsen, J Van Acker, I De Windt


Report on COST E37 Round Robin Tests – Comparison of results from laboratory and field tests
2013 - IRG/WP 13-20535
A round robin involving 15 European participants was set up in 2006. The round robin consists of both a field test according to the double layer test method and a laboratory test with two different preconditioning methods. When comparing EN 84 preconditioning (two weeks water leaching) with natural preconditioning (1 year in field, above ground) according to CEN/TS 15397, no significant difference...
M Westin, E Conti, J Creemers, P-O Flæte, A Gellerich, I Irbe, M Klamer, B Mazela, E Melcher, R Möller, L Nunes, S Palanti, L Reinprecht, E Suttie, H Viitanen


Resistance of WPC against wood destroying fungi
2013 - IRG/WP 13-40627
The investigation of biological durability is a fundamental topic to assess the performance of Wood Plastic Composites (WPC) particularly for outdoor applications. In the last years, different test setups based on existing standards on the field of wood as well as the field of plastics were used for WPC. But the test methodologies give different information about the durability of the tested mater...
A Gellerich, S Bollmus, A Krause


CreoSub – New protection technology to substitute creosote in railway sleepers, timber bridges, and utility poles
2014 - IRG/WP 14-30644
Creosote oil is one of the oldest industrially used wood preservatives. Due to its toxic profile, the European Commission has restricted the use of creosote specific applications, but it is highly controversial within the European Commission. Its approval for use after 2018 is very questionable and may depend on derived research results until then, i.e., the viability of alternatives developed to ...
U Hundhausen, K-C Mahnert, A Gellerich, H Militz


Some comments on durability testing of WPC according to EN 15534-1
2015 - IRG/WP 15-40695
The standard EN 15534-1 (2014) gives advice for broad characterization of WPC materials and products. It contains instructions for test procedures concerning different properties e.g. mechanical properties, thermal properties, as well as durability. In this paper some WPC materials from the market were tested for their resistance against brown rot. Furthermore, the water uptake and bending prope...
S Bollmus, A Gellerich, H Militz


How does the test methodology influence the outcome of durability testing of thermally modified wood
2015 - IRG/WP 15-40699
Thermally modified wood is commercially available on the European market since many years. Today, many production units with various production capacities and different modification processes exist. Industrial scale wood heat treatment processes, under the trade name of ThermoWood were developed in Finland. ThermoWood has two standard treatment classes with different target properties, namely Ther...
A Gellerich, S Bollmus, H Militz


Selection of most aggressive test fungi for modified wood - Practical laboratory experience
2016 - IRG/WP 16-20579
One main objective of wood modification processes is the improvement of the durability against wood destroying organisms. Therefore, investigations of the resistance against wood destroying fungi have been one of the main focus within the last years. For the interpretation of the durability results, the selection of suitable test fungi is one of the main questions. A “wrong” fungus species may...
A Gellerich, S Bollmus


Variation in moisture content in field trials according to use class 3.2 conditions
2016 - IRG/WP 16-20580
Different test methods to determine the durability of wood in use class 3 (EN 335:2013) are available. Fungal degradation of wood requires liquid water. Different Standards (EN 335-1:2006; DIN 68 800:2011) specify the risk for decay with moisture content (mc) of above 20%. EN 335 (2013) does not specify moisture content but rather defined limited wetting conditions (use class 3.1) or prolonged wet...
S Bollmus, A Gellerich, H Militz


Impregnation of railway sleepers - Pressure gradient and transversal penetration
2016 - IRG/WP 16-40731
Based on the possible ban of creosote in the future, the need for oil based alternative products has gained in importance. Due to possible differences in impregnation properties compared to creosote the need for re-implementing former technology is given, to determine if momentarily used impregnation processes have to be modified. The here reported tests measure the pressure gradient during the im...
M Starck, A Gellerich, H Militz


10 year Report on COST E37 Round Robin Tests – Comparison of results from laboratory and field tests
2017 - IRG/WP 17-30718
A round robin involving 15 European participants was set up in 2006. The round robin consisted of both a field test according to the double layer test method and a laboratory test with two different preconditioning methods. The laboratory test results were reported in an earlier IRG paper (IRG/WP13-20535) but are included also in this paper in order to facilitate the comparison with the field test...
M Westin, E Conti, J Creemers, P-O Flæte, A Gellerich, I Irbe, M Klamer, E Melcher, R Moeller, L Nunes, S Palanti, L Reinprecht, E Suttie, H Viitanen


Evaluation of surface cracks on wood – physical assessment versus subjective sensation
2017 - IRG/WP 17-20617
In the presented studies from the University of Goettingen (Study I) and the University of Hannover (Study II), the assessment of cracks with different methods and their acceptance in general as well as depending on different target groups are investigated. The aim was to determine which factors are relevant for a crack evaluation and which visual impression of a wooden surface is tolerable for co...
A Gellerich, C Brischke, L Emmerich, L Meyer-Veltrup, P Kaudewitz


Weathering protection of European hardwoods through double modification
2017 - IRG/WP 17-30715
Beech and poplar were thermally modified, treated with melamine resin and both treatments were combined. The weathering performance (cracks and general appearance) of modified beech and poplar was assessed in natural weathering and correlated to material properties such as work in bending (WB) and Brinell hardness. In addition, the equilibrium moisture content after exposure of 12 months and subse...
G Behr, A Gellerich, S Bollmus, H Militz


Penetration behaviour of different hydrophobic carrier substances for oily wood preservatives in Beech and Scots pine sapwood
2017 - IRG/WP 17-40804
The use of creosote as a wood preservative has a long history. Current areas of application are railway sleepers, transmission poles, timber bridges and marine applications. If the approval for creosote will not be prolonged, alternative wood preservatives will be needed. As the penetration behaviour after pressure impregnation of different alternative oily products in this fields of application i...
M Starck, A Gellerich, H Militz


Impact of sapwood portions on the durability of adjacent heartwood of Pinus sylvestris, Pseudotsuga menziesii and Quercus robur. Part 1: Laboratory studies
2018 - IRG/WP 18-10922
Sapwood is generally considered as non-durable and assigned to durability class DC 5 according to European standards independent from the wood species. It is commonly agreed that sapwood decays faster than adjacent heartwood, but it is controversially discussed whether sapwood serves as feeder material and thus accelerates onset and progress of decay in more durable heartwood or decays independent...
C Brischke, P Homann, A Gellerich


Testing the durability of timber products above ground using the block-test method – A critical review
2018 - IRG/WP 18-20637
The block-test method for testing the durability of wood and wood products above ground is reviewed critically with respect to practical aspects, moisture loads, corresponding decay development, and the possibilities of assessing test specimens by determining the dynamic modulus of elasticity (MOEdyn) of wood. In total, 36 blocks representing different modifications of the original set-up and a wi...
C Brischke, A Gellerich, H Militz


Towards durability classification of preservative treated wood – first attempts using different European standards
2018 - RG/WP 18-20638
EN 350 (2016) gives guidance on methods for determining and classifying the durability of wood and wood-based material against biological wood destroying agents. “Wood-based materials are those derived from trees and include amongst others: untreated wood, heat treated wood, chemically modified wood, glue laminated wood, wood-based panels, wood polymer composites and wood treated with wood prese...
S Bollmus, A Gellerich, C Brischke, H Militz


Performance of acetylated wood in aquatic applications
2018 - IRG/WP 18-40822
Acetylation of wood to enhance its resistance against wood decaying fungi and insects has been studied extensively under both laboratory and terrestrial field trials. Also several studies are investigating the performance of acetylated wood in marine and fresh water exposures. This paper updates nine year marine tests with acetylated radiata pine in Hejlsminde (Denmark) and presents data on 3 year...
F Bongers, S Palanti, A Gellerich, J J Morrell, J Creemers, J Hague