Your search resulted in 117 documents. Displaying 25 entries per page.
Studies on accelerated ageing procedures with TBTO-treated wood
1985 - IRG/WP 2244
The efficacy of various procedures for accelerated ageing of organotin based wood preservatives in treated wood has been investigated. It was found that leaching of the treated wood samples in water according to the European Standard EN 84 was not satisfactory for organotin based preservatives and is probably also unsuitable even for other types of organic solvent preservatives. Keeping tributyltin oxide (TBTO) treated samples in a heating cabinet at 70°C for five weeks, however, had a considerable effect on the breakdown of TBTO and the subsequent decay test. Therefore, an ageing procedure involving a heating period should be considered for all organic solvent wood preservatives. The investigation also confirmed that elevated temperatures accelerate the degradation of TBTO and that there is a strong correlation between the percentage of TBTO in the wood and its resistance against decay.
J Jermer, M-L Edlund, B Henningsson, W Hintze
Depletion of boron and copper from CCB treated test specimens using different leaching protocols
2004 - IRG/WP 04-50208
The objective of this study was to measure the depletion of inorganic wood preservative components regarding the proposed OECD guideline "Estimation of emissions from preservative-treated wood to the environment: laboratory method for wooden commodities exposed in the use class 4 and 5" as part of the project "Investigations concerning the influence of test parameters on the release of biocidal actives from treated timber in leaching tests". Pine sapwood specimens (50x10x150) were pressure impregnated with CCB according to European Use Class 4. Before leaching all samples were stores 4 weeks for fixation. In addition leaching tests were performed according to the European Standard EN 84 by means of EN 113 blocks. Parallel investigations were carried out between two laboratories to assess the repeatability and comparability of the methods. The results of chemical analysis of leachates taken at different time intervals show that similar depletion rates were determined for copper and boron independent on the leaching protocol used. However, the loss of copper as well as chromium in short term dipping experiments was often lower than the detection limit. Furthermore it can be stated that the difference between parallels was higher for the results which were obtained for the OECD guideline that EN 84. A comparison of both laboratory results indicate that a quite good repeatability is given in case of the CCB treated material.
E Melcher, R-D Peek, U Schoknecht, R Wegner
Tebuconazole, a new wood-preserving fungicide
1990 - IRG/WP 3634
TEBUCONAZOLE, an anti-fungal triazole compound, has been tested to assess the effectivness as wood preserving fungicide. Tests were made with the active ingredient and also in formulations against basidiomycetes, blue-staining fungi and mould. Results of the DESOWAG laboratories and also from official institutes will be presented. In addition to this there were made different toxicological and ecotoxicological trials according to OECD and EPA guidelines
B Wüstenhöfer, H-W Wegen, W Metzner
Proposals for collaborative work on laboratory soft rot testing
1986 - IRG/WP 2265
Proposals for collaborative experiments based on soil burial are presented. It is intended to study the use of defined horticultural loams with a view to obtaining more reproducability in laboratory soft rot tests.
D J Dickinson, S M Gray
Final proposals for collaborative work on laboratory soft rot testing
1987 - IRG/WP 2292
In this paper proposals are made to scope, timbers, preservatives, leaching, drying, soil type, moisture content, soil burial (blocks and stakes), incubation and dry weight determination and the expression of results.
D J Dickinson, S M Gray
Triazoles: Synergism between propiconazole and tebuconazole
1995 - IRG/WP 95-30092
The synergistic action of the two triazoles propiconazole and tebuconazole against wood rotting fungi can clearly be demonstrated by determination of toxic values according to Standard EN 113. The results show that by combining both triazoles a better balanced spectrum of activity can be achieved. The reduction of the toxic values against the white rot fungus Coriolus versicolor (toxic values of the combination remarkable below the values of the individual active ingredients) proves particularly clear the synergistic behaviour of the combination. Additional trials with such combinations (L-joint-tests, lap-joint-tests, soil block tests) are initiated.
H-U Buschhaus, A R Valcke
Evaluating possibilities of leaching of deltamethrin and TCMTB (insecticides and fungicide for protecting wood) by rain water or by soaking in water
1988 - IRG/WP 3464
Deltamethrin and TCMTB have been subjected to several field leaching tests on freshly fallen trees and in the laboratory, using standard EN 84. All the trials gave the same results and confirm that Deltamethrin and TCMTB are not washed out after they have been allowed to penetrate the trunk surface properly. According to the EN 84 standard, less than 1% Deltamethrin and less than 1.7% TCMTB were released in water after a 14 day leaching period
J S Duguet, V Dartigues
Artificial weathering exposure as an alternative for standard ageing according to EN 84 (leaching) and EN 73 (evaporation)
2002 - IRG/WP 02-20254
In order to verify potential weaknesses of wood preservatives fungal tests are carried out after ageing of wood preservative treated test blocks. The European standard EN 599 as a framework for efficacy assessment of wood preservatives includes the use of two ageing methods prior to fungal testing, namely a leaching method (EN 84) and an evaporation method (EN 73). The European research project "F.A.C.T." aimed amongst other objectives to provide in more realistic alternatives for both ageing methods. Artificial weathering systems generally used to assess the weathering resistance of exterior coatings was looked at as an alternative. For this purpose artificial weathering devices were selected which besides a control of temperature and light also allow for the impact of moisture by means of water spraying. UV cabinets with spray option were used to evaluate the effect of ageing of three wood preservatives: a waterborne Cu-HDO preservative, an oilborne triazole combination and a TBTO reference preservative. Based on EN 113 Basidiomycete testing of aged specimens a range of equivalent UVS systems proved to be suitable as an alternative ageing system prior to EN 84 and EN 73.
J Van Acker, M Grinda, D J Dickinson
Soft rot tests with soils of different origins
1984 - IRG/WP 2226
In the BAM a comparative soft rot test with 9 different types of soil (one soil each from Canada, New Zealand and Switzerland and 6 soils from laboratories in Germany) were carried out. The pH values of the different soils ranged from 3.2 to 7.1, and the amounts of organic matter were between 4 and 44% (w/w). The test specimens - Pine sapwood blocks treated with different concentrations of a CCA preservative - were the same for all tests as well as the test vessels and the test conditions. The weight losses which were determined after an 18-week test period were 5...22% of the untreated controls; the lowest decay rates were obtained in the soils with the lowest pH values (3.2 to 4.7). Despite the very different characteristics of the 9 test soils used, the same toxic limits of 4.9 to 7.3 kg/m³ of the tested CCA preservative were obtained; apart from 2 soils where they were lower by one concentration. The final moisture contents of the untreated controls ranged from 55...169% (w/w), those of the blocks treated with 1% CCA solution were 33...67% (w/w).
M Gersonde, W Kerner
Laboratory Leaching Tests to Study the Effects of Post-Treatment Storage Periods on CCA Leachability and Fixation in Treated Permeable and Refractory Malaysian Hardwoods
2006 - IRG/WP 06-50240
The biological resistance and environmental safety of CCA-treated wood relies on the extent of post-treatment storage fixation of CCA in wood prior to being utilized. A study on the comparative leachability (fixation) of CCA-treated refractory and permeable heartwoods of 3 Malaysian hardwoods subjected to different post-treatment storage (fixation) periods of up to 4 weeks, at 2 laboratory leaching tests of the general procedure of EN84 was conducted. End-sealed test wood blocks of Malaysian species [permeable Menggris (Koompassia malaccensis) and Perah (Elateriospermum tapos), refractory Acacia mangium] were treated with CCA to target retention of 5.6 kg/m3, immediately stored to fix at ambient conditions for 0 and 48 hours, 1, 2 and 4 weeks, followed by a 2 weeks leaching test to determine cumulative leaching losses of copper (Cu), chromium (Cr) and arsenic (As). Generally, levels of leached CCA components were: 4.0 – 47.4 µg/cm2 Cu, 9.1 – 127.0 µg/cm2 Cr, and 5.2 – 56.9 µg/cm2 As. For all leachate elements, there were less distinct variations in leaching losses (P<0.05) between 4 storage (fixation) periods, more significant variation between unfixed and stored fixed blocks and between refractory and permeable wood species. Component leaching losses were greater in refractory than permeable heartwoods of timbers, while increasing with reduced storage periods overall. No significant differences in CCA leaching losses were found between EN84 method (consisting of initial vacuum impregnation of wood in water) and the variant of the EN84 method (initial immersion of wood in water), implying that the former method could not result in higher CCA leaching losses than the latter method.
A H H Wong, H C Lai, N P T Lim
Comparative Laboratory Leaching Test Methods to Study Post-Treatment Storage Period Impacts on CCA Leachability and Fixation in Treated Kempas (Koompassia malaccensis) Heartwood
2007 - IRG/WP 07-20376
Three laboratory leaching test methods were compared to determine the effects of different post-treatment storage fixation periods on leachability/fixation of CCA components from treated kempas (Koompassia malaccensis) permeable heartwood. End-sealed test wood blocks of permeable were treated with CCA to target retention of 5.6 kg/m3, immediately stored to fix at ambient conditions for 0 and 48 hours, 1, 2 and 4 weeks, followed by a 2 weeks leaching test comparing 3 leaching tests: the methods of EN84 (consisting of initial vacuum impregnation of wood in water), EN84-1 (replacing initial vacuum impregnation with initial immersion of wood in water) and a new, and least severe, test EN84-2 (daily routine of soaking wood for 5 hours in water followed by drip drying for 19 hours). Leachates harvested from these leaching tests were analysed for cumulative leaching losses of copper (Cu), chromium (Cr) and arsenic (As) that occurred over the 2 weeks leaching period. Overall, leached CCA elements ranged from 0.48 – 4.02µg/ml Cu, 0.61 – 5.76 µg/ml Cr and 0.46 – 4.02 µg/ml As. There were significant variations in leaching losses (P<0.05) between unfixed and stored fixed blocks among the 3 laboratory leaching test methods. Significant variations of Cu, Cr and As levels existed between the least severe method and the other two methods that used prolonged immersion of wood in water. However, there were no significant differences in CCA leaching losses between EN84 method and the EN84-1 method, while the merits of the least severe leaching regime as indicators of realistic CCA leaching of “fixed” treated wood aboveground outdoors are discussed.
A H H Wong, H C Lai
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 could be noted for untreated controls, thermally modified wood or CCA impregnated wood. However, for wood treated with a metal-free organic preservative, a clear difference could be seen where much of the efficacy seen after EN 84 preconditioning is lost when natural preconditioning is used instead. In the field tests, the control pine performs similar in all fields whereas both thermally modified and preservative treated wood performs much better in the Nordic fields than in the Mid- and Southern European fields. The thermally modified wood performs almost as poor as the controls in the Southern European fields, whereas the organic preservative treated wood performs well in these fields. In the six Mid-European fields, the organic preservative treated and thermally modified wood performs equally poor but much better than the controls. The best compliance between field performance and laboratory test results is obtained when comparing the average results from the field tests with results from EN 113 tests with Postia placenta after natural preconditioning according to CEN/TS 15397.
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
Relevance of natural pre-weathering for laboratory decay tests with native, modified, and preservative-treated wood
2013 - IRG/WP 13-20522
The on-going development of new wood protection systems is hampered by the long term field tests currently in use. New accelerated test methods and novel methods for faster and more accurate evaluation of wood protection methods are requested. For both field decay tests and accelerated laboratory decay tests, limitations are imposed. This study is part of the research program ‘WoodBuild’, which aims at developing a comprehensive test methodology for determination of wood durability. Field tests under various exposure conditions are regarded as well as laboratory tests. An overall objective is to find methods having the potential to reflect real life situations for all use classes. Therefore this particular study aimed at investigating the differences in mass loss with a mini-block test (Bravery 1979) following ageing with either leaching (EN 84) or natural weathering. The aim of this paper is not focussing on the durability (and definitely not on the efficacy) of any treatment but to highlight the differences in durability between naturally weathered samples and laboratory leached samples. The present study indicates that natural weathering and laboratory ageing procedures influence various wood species and various wood treatments differently with regard to durability. For preservative treated wood, none out of six treatments had a significantly higher mass loss for P. placenta when the samples were pre-weathered compared to pre-leached. For T. versicolor, 3 out of 6 treatments showed higher mass loss after natural pre-weathering. For the modified woods, 2 out of 7 treatments had a significantly higher mass loss for P. placenta when the samples were pre-weathered compared to pre-leached. When exposed to T. versicolor, 4 out of 7 treatments had a higher mass loss for P. placenta when the samples were pre-weathered. The mass loss for T. versicolor for the softwoods and hardwoods did not seem at all to be affected by the pre-treatments. Although, when exposed to P. placenta, 3 out of 9 softwoods and 1 out of 5 hardwoods had a significantly higher mass loss when the samples were pre-weathered compared to pre-leached. The present study indicates that the impact of natural weathering on mass loss seems not only to be treatment dependent but also wood species and test fungus dependent. The effects of natural weathering might be explained by the losses of active substances from treated wood but also the biological influence of microorganisms is a contributing factor. Taken this into account, it seems very important to consider the effect of any pre-treatment on both, the test materials and the untreated and per definition non-durable reference species.
A Pilgård, C Brischke, L Meyer
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 results. As expected, the decay generally developed more rapidly at the southern European compared to the northern European field sites. However, the rank order of the different test groups concerning average decay ratings were the same for most field sites – Untreated pine sapwood controls had the highest decay ratings followed by TMT-UC2 (Thermally Modified Timber treated for use class 2 application), TMT-UC3, metal-free organic preservative in low retention, metal-free organic preservative in high retention, CCA in medium retention, and finally CCA in high retention that had very low decay ratings. The best compliance between field performance and laboratory test results is obtained when comparing the average results from the field tests with results from EN 113 tests with Postia placenta after natural preconditioning according to CEN/TS 15397. When evaluating the test methods it was clear that CEN/TS 15397 before the EN 113 test in laboratory seems to give far more relevant results than EN 113 after preconditioning according to EN 84 (water leaching for 2 weeks). The double layer field test does not function the way it was meant after failure ratings were reached for one or more stakes within a test group leading to collapse of the deck. This has occurred not only at the Southern European field sites but also in some cases for mid-European and Nordic test sites. After this type of collapse has been reached it is doubtful whether there is any point with continuing the test and therefore the test has now been terminated in some fields.
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
Insect resistance of preservative treated tropical plywood against Lyctus
1990 - IRG/WP 1453
Seven plywood types composed of tropical wood species, vulnerable to Lyctus, were treated with various commercial water-borne and oil-borne preservatives. A wide range of preservative retentions was obtained by treating boards with dip treatment, steeping, double-vacuum and vacuum-pressure impregnations. Selected samples were subsequently tested for their insect resistance against Lyctus africanus during 6 to 8 months according to European Standard EN 20. All control samples were attacked, except one Obeche plywood exhibiting only 50% attack. Water-borne preservative solutions containing arsenic, boron or fluoride could not prevent attack at common retention levels for interior use e.g. lower than 5 kg/m³. Quaternary ammonium compounds showed no insecticidal efficiency, up to 3 kg/m³. TCMTB at 1.5-1.7 kg/m³ proved to be able to reduce slightly the susceptibility for insect attack. Organic insecticides gave the best results, with nearly no attack for plywood treated with lindane or cypermethrin. In spite of a preservative uptake of 25 to 30 kg/m³, endosulfan only could reduce attack by 50%. Protection by permethrin at 0.1% a.i. required a retention of 28 kg/m³. Besides the fact that variability in wood species and composition of the plywood are leading to different retention levels, variation in penetration and distribution of a.i., and as a consequence to a different insect resistance of the impregnated boards, some poor results were directly related to inadequate insecticidal activity and/or concentration of a.i. in some commercial formulations for Lyctus control.
J Van Acker, M Stevens, M Pallaske
Interspecific variability of European oak durability against white rot fungi (Coriolus versicolor): Comparison between sessile oak and peduncle oak (Quercus petraea and Quercus robur)
2001 - IRG/WP 01-10393
The knowledge of wood natural durability against biologic predators enable its external use. The resistance of European oak wood was reported like durable according to the EN 350-2. However, some individuals may contain high durable wood. Our research was focused to understand this variability in oak population that represent the first french species (4.1 millions of ha). Natural durability of European oak heartwood (Quercus petraea and Quercus robur) against white rot fungi (Coriolus versicolor) was tested according to european standard EN 113. The experimental material consists in 23 oaks robur and 26 petraea oaks sampled from 9 French regions. For each tree, 3 twin samples were taken off from heartwood situated at 1.30 m from the bottom of the tree. Different effects were tested by hierarchic variance analysis: "species", "forest within species" and "tree within forest". The tree effect is very significant for biologic natural resistance. Variability between species was also demonstrated. Although the species effect is significant, it's relatively weak compared with tree differences (it was declared significant 5%). Durability classification was determined according European standard EN 350-1. 69.2% of petraea oak trees are classified as high durable, 19.2% durable, 7.7% moderately durable and 3.8% slightly durable. In the case of robur oak 91.3% of trees are classified as high durable and 8.7% durable.
N Ayadi, B Charrier, M Irmouli, J P Charpentier, C J Allemand, F Feuillat, R Keller
Temperature influence on the growing velocity and cellulolytic activities of Poria placenta strains from several locations
1986 - IRG/WP 2263
The differences observed on the FPRL 280 Poria Placenta strain at several Research European Laboratories for determining up the fungicide effectiveness of wood preservative has carry us to do a comparative study about the cellulolytic activity and growth velocity of each of this strains at different temperatures (22, 24 and 28°C). The results show significative differences when the temperature is changed.
A M Navarrete, M T De Troya
Agenda Plenary 1978
1978 - IRG/WP 84
Possibility of use of wood species per class of biological risks. Attempt to determine criteria based on Pr EN 350-1/2/3
1992 - IRG/WP 92-2409
Rapport sur l'activité du CEN/TC 38
1983 - IRG/WP 2204
Resistance of the wood of Eucalyptus saligna and Paulownia tomentosa against some wood rotting fungi
1997 - IRG/WP 97-10238
Paulownia tomentosa and Eucalyptus saligna are not autochthonous species in Slovenia and we determined the resistance of their wood against our most common wood rotting fungi. The resistance against Coniophora puteana, Gloeophyllum trabeum and Trametes versicolor was determined according to EN 113 and compared to the resistance of beech (Fagus sylvatica) wood. It was stated, that both paulownia and eucalypt wood samples are much more resistant than beech wood. Especially paulownia wood was outstanding by its natural resistance against tested basidiomycetes.
F Pohleven, M Petric
Determination of the preventive efficacy against wood destroying basidiomycetes fungi, EN V 839 - CEN/TC 38 WG 9
1993 - IRG/WP 93-20015
The WG 9 of CEN TC/38 has presented to EC a mycological test to assess efficacy of preservatives applied by surface process. This method is now an experimental standard (EN V 839) which has to be approved by the different european delegations. The following paper is not the standard as it has been proposed but is a presentation of the principle of the method. The experimental standard specifies a laboratory method of test which gives a basis of the assessment of the preventive action of a wood preservative when applied as a surface treatment against Basidiomycetes fungi. This method is applicable to formulations of preservatives in a ready to use form (organic formulations, organic water-dispersible formulations, water-soluble materials). Series of susceptible wood species specimens are treated on longitudinal faces whith the preservative in test using brushing as surface procedure. Test specimens are then exposed by an intermediate mesh to feeder blocks infestedby pure culture of Basidiomycetes fungi in sterile conditions and penetration of fungi is assessed on cross section sawn in the samples at the end of the test.