Your search resulted in 531 documents. Displaying 25 entries per page.
Soil-bed studies. Part 2: The efficacy of wood preservative
1983 - IRG/WP 2205
Various methods of decay assessment were investigated. Three stages or phases of decay were identified which could be used to describe the efficacy of a preservative system or virulence of a soil-bed testing medium. These included the lag, decay, and senescent phase. Premature senescence could arise if wood samples became waterlogged. It was concluded that time to failure was unsuitable as a method of decay assessment. Decay assessment by deflection testing was therefore limited to assessing linear losses in elasticity against time.
P Vinden, J F Levy, D J Dickinson
On the use of probit analysis for assessing the toxicity of wood preservatives
1974 - IRG/WP 244
To elucidate the general character of the action of the toxic material on the fungus, it is sufficient to carry out preservative tests using the previously described procedure, but in doing so, it is necessary somewhat to change the number of specimens and their arrangement in jars. Five concentrations of toxic material are tested simultaneously. For the testing of one preservative ten jars should be used in each of which are placed 50 specimens, comprising 10 of each of the five concentrations. The proposed arrangement of the specimens in jars makes due allowance both for the variation in the reaction of the individual sections of the mycelium in one jar (ten specimens) and for the variation in the reaction of the fungus in the different jars (ten groups of specimens). The effect of each concentration of toxic material on the fungus may, therefore, be assessed from the result of observing its reaction on a hundred specimens tested in all ten jars. With this procedure the author investigated the toxicity to Coniophora of sodium fluoride, sodium chloride and sodium silicofluoride, copper sulphate, zinc chloride, ammonium fluoride and ammonium pentaborate. The results are given in Table 1. Complete curves of the toxic effect were not obtained for all the formulations, but for the majority of them levels of transition from incomplete to practically complete protection of the timber against destruction by the fungus were established. The test results for sodium fluoride, using the given procedure, are represented graphically in Fig.1 (curve 2). It can be seen from Fig.1 that the change of reaction of Coniophora in timber containing different amounts of NaF is well described by an S-shaped curve, similar to the integral function of a normal distribution. Similar graphs are also obtained when testing other preservatives. The nature of the curve shows yet again that different probit-analysis methods may be used when testing preservatives in timber. Fig.3 shows the probit curves of the effect of sodium fluoride. Since in our case the curve is symmetrical and not lengthy, there was no need to use a logarithmic scale for the axis of abscissae. It can be seen from Fig.3 that, by using a normal distribution as a model for transforming the NaF toxic effect curve, rectilinear graphs are obtained. With such graphs it is easy to find the different levels of timber protection, and also to assess the variation of the reaction of the wood-destroying fungus by computing the mean dose and the standard deviation by the known methods of probit-analysis. From the probit v. NaF content graph (Fig.3) is found the amount of sodium fluoride necessary for protecting the timber of pine sapwood against destruction by Coniophora in 95 per cent of cases. It is 0.168 kg/m³. When determining the said level of protection by the author's proposed procedure, the value obtained was 0.136 kg/m³, i.e. 0.032 kg/m³ less. This is due to the fact that in the latter case the number of specimens tested was comparatively small. The proposed method, therefore, gives an overall picture of the protection of the timber by a specific preservative against the action of wood-destroying fungus and enables the amount of toxic material, which should be selected for a more detailed investigation by the previously reported procedure, to be determined.
D A Belenkov
The microbial ecology of treated birch stakes in a soil-bed
1983 - IRG/WP 1209
The microbial ecology of small birch stakes exposed in soil beds in two Fungus Cellars was investigated. Patterns of fungal colonisation and decay initiation are described in untreated birch and copper fluosilicate-treated stakes. Results are based on fungal isolation onto selective media and direct light microscopical observations of decay features. In untreated stakes there was a rapid build-up of soft rot fungi and extensive soft rot decay within two weeks which increased with time. In treated stakes the frequency of isolation of soft rot fungi was lower at the ground line, increasing to a maximum at the base of the stakes. Soft rot decay was initiated at the base of the stakes and this may be due to loss of the preservative by cationic exchange between elements of the preservative and cations in the soil solution. The influence of soil moisture content on decay was also indicated. Treated stakes in the drier soil bed showed signs of basidiomycete attack at the ground line, soft rot being limited to the wetter basal zones.
C P Clubbe
Preliminary study of the fungicidal and structural variability in copper naphthenates and naphthenic acids
1996 - IRG/WP 96-30114
Copper naphthenates, an oil-borne wood preservative listed by the American Wood-Preservers' Association (AWPA), is manufactured by complexing copper(II) with naphthenic acids. Prior to AWPA listing as a wood preservative, field experiments showed that copper naphthenates generally had good stability and were active against wood-destroying organisms. Recently, however, there have been reports of some copper naphthenate-treated poles rapidly failing. One possible explanation for the varying effectiveness could be that the structure, and resulting biological activity, of the naphthenic acids used to make copper naphthenate may vary. To test this hypothesis several naphthenic acids and copper naphenates were obtained and their fungicidal activity against three wood-destroying fungi measured. In addition, the chemical structure of the naphthenic acids were examined by proton- and carbon- NMR. Different activities were observed, especially against a copper-tolerant fungus. Some apparent correlations were seen between the fungicidal activity and chemical structures for the few samples studied.
T Schultz, D D Nicholas, L L Ingram Jr, T H Fisher
Sequestration of copper ions by the extracellular mucilaginous material (ECMM) of two wood rotting basidiomycetes
2004 - IRG/WP 04-10533
The radial growth rate of colonies originating from either whole or ECMM-free inocula of Coriolus versicolor was investigated. The presence of ECMM allowed colonies to maintain higher growth rates than those form ECMM-free inocula up to 2 mM CuSO4 in the medium. The ECMM of C. versicolor and G. trabeum was able to reduce the diffusion of copper ions in solution. The ‘raw’ ECMM of both fungi had a greater ability to reduce the diffusion of copper ions than ECMM which had been subject to dialysis to remove soluble, low molecular weight components. The ‘insoluble’ fraction of ECMM for both species was more effective than the ‘soluble’ fraction at reducing the diffusion of copper ions. It is concluded that ECMM confers some protection to hyphae against the toxic effects of copper ions on growth in vivo and that this due to the binding of copper ions to both the polysaccharide and to low molecular weight components of the ECMM
D Vesentini, D J Dickinson, R J Murphy
Influence of different fixation and ageing procedures on the leaching behaviour of copper from selected wood preservatives in laboratory trials
2003 - IRG/WP 03-20264
The paper focuses on the role of different parameters, such as fixation, sample size, wood species, and leaching in internationally standardized ageing procedures for wood preservatives from Europe, Japan and the United States. The leaching protocols used were EN 84, JIS K 1571 and AWPA E11 protocols. The wood species were Scots pine, Sugi and Southern Yellow Pine respectively. Three types of commercially important copper-based wood preservatives were used as model formulations, namely copper/copper-HDO, ammoniacal copper/quat and CCA. The most important factors determining the extent of copper leaching in the different lab trials were the sample size (volume/surface ratio) and the fixation conditions prior to leaching. On the other hand, the wood species and the leaching protocol itself were found to have only minor influence on the copper leaching rate in the test methods included in this study.
J Habicht, D Häntzschel, J Wittenzellner
International collaborative laboratory comparison of two wood preservatives against subterranean termites: Third update and first report
1996 - IRG/WP 96-10174
At the 24th annual meeting of IRG in Orlando, USA, in May 1993 an international subterranean termite laboratory bioassay to compare the various preferred termite protocols used by IRG termitologists was initiated. The author was nominated to co-ordinate this comparative laboratory evaluation of two wood preservatives, copper-chrome-arsenic (CCA) and copper naphthenate (Cu-Na) against the subterranean termites used as test termites in Australia, France, Japan, Thailand, United Kingdom and the Unites States of America. Solutions of these two wood preservatives were prepared and impregnated into Pinus radiata wood blocks to obtain loading of 0.0, 0.5, 1.0, 2.0 and 4.0 kg/m³ respectively. All preservative treatments were carried out at the Division of Forestry and Forest Products in Melbourne. The treated specimens were dispatched to the participating researchers who subjected these specimens to attack by their test termite species, and have now returned the specimens to Melbourne. This paper reports the amount of wood consumed and the mean mass loss (%) on both treated and untreated wood blocks by the termites in the various laboratory bioassays.
J R J French
Types of decay observed in CCA-treated pine posts in horticultural situations in New Zealand
1984 - IRG/WP 1226
The few reported failures of 11-12-year-old horticultural posts in New Zealand in 1982 were caused by brown-rot. A subsequent survey of CCA-treated posts in all the major horticultural areas has revealed decay of many posts. A microscopic examination of these posts has shown decay by brown-rot, white-rot, soft-rot and bacteria. Several types of bacterial decay have been observed.
J A Drysdale, M E Hedley
Di-sodium fluorophosphate, a new fluorine containing, water-borne wood preservative
1986 - IRG/WP 3373
The physical, chemical properties of Di-sodiumfluorophosphate (Na2PO3F) are compared with those of a trade-mark SF-salt. The opposition of biological activity and toxicological data showed that Di-sodiumfluorophosphate may be a suitable alternative to SF-salts ( based on MgSiF6).
D Seepe, W Metzner
Results of chemical analyses in the field of wood preservation in the Bundesanstalt für Materialprüfung
1973 - IRG/WP 321
The results of qualitative and quantitative chemical analyses of wood preservatives are often the basis for evaluating the various works in the field of wood preservation. In the past 10 to 15 years a number of such works was carried out in the Bundesanstalt fur Materialprüfung, Berlin-Dahlem, dealing with the identification and effectiveness of wood preservatives and with methods of wood preservation. Fundamental realisations were made which will be summarised below. It seems advisable to differentiate between inorganic and organic chemical wood preservatives and methods of analyses. These are two distinct fields which differ also with regard to the analytical techniques applied.
H J Petrowitz
Electrodialytic remediation of creosote and CCA treated timber wastes
2002 - IRG/WP 02-50190
There is a growing concern about the environmental issue of impregnated timber waste management, since an increase in the amount of waste of treated wood is expected over the next decades. Presently, no well-documented treatment technique is yet available for this type of waste. Alternative options concerning the disposal of treated wood are becoming more attractive to study, especially the ones that may promote its re-use. Inside this approach, the electrodialytic process (ED) seems a promising technique for removal of preservative chemicals from treated wood waste. The method uses a direct electric current and its effects in the matrix as the “cleaning agent”, combining the electrokinetic movement (mainly due to electromigration, but also electro-osmosis and electrophoresis), with the principle of electrodialysis. This work reports results from the application of the electrodialytic process to an out-of-service Portuguese creosote and CCA-treated Pinus pinaster Ait. railway sleeper and pole. The behaviour of the process is described and the main results discussed. The average removal rate, estimated in accordance with prEN 12490, for creosote from treated timber waste was around 40 %.. For CCA treated timber waste, experimental conditions that could optimise the process efficiency (e.g. current density, time) were studied. The highest removal rates obtained until now, in our studies, were 93 % of Cu, 95 % of Cr and 99 % of As for sawdust using 2.5 % oxalic acid (w/w) as the assisting agent. For CCA treated wood waste in the form of chips, the best removal rates obtained until now were 84 % of Cu, 91 % of Cr and 97 % of As.
E P Mateus, A B Ribeiro, L Ottosen
Fungicidal activity of some organic solvents, copper carboxylates and their complexes with 2-aminoethanol
1997 - IRG/WP 97-30136
We evaluated the activity of eight organic solvents against wood - rotting fungus Trametes versicolor in order to choose the most appropriate one for rapid screening tests of some copper(II) carboxylates and their adducts with 2-aminoethanol. Their activity against the selected fungus was classified in the following order: chloroform > N,N-dimethylformamide > acetonitrile > methanol > dimethyl sulfoxide > ethanol > acetone. The non-polar white spirit did not dissolve in the growth medium and the results could not be directly compared with the results for other solvents. As an appropriate solvent for screening of the tested copper(II) carboxylates, dimethyl sulfoxide (DMSO) was chosen. Minimal inhibitory concentration against Trametes versicolor of the screened carboxylates was in the concentration range of 1x10-4 to 1x10-3 mol/l. Coordinated amine ligands slightly, and not significantly, decreased fungicidal properties of the tested carboxylates.
M Petric, F Pohleven
Termite resistance of pine wood treated with chromated copper arsenates
1997 - IRG/WP 97-30128
Two four-week, no-choice laboratory tests were performed with CCA-treated southern yellow pine and radiata pine against Formosan subterranean termites, Coptotermes formosanus. CCA retentions as low as 0.05 kg/m3 (0.03 pcf) provided protection from all but light termite attack (rating of 9 on a 10-point visual scale). Similar and consistent light attack on wafers containing retentions as high as 6.4 kg/m3 (0.4 pcf), coupled with complete termite mortality, demonstrates that the mode of action of CCA treatments relies upon toxicity rather than having any repellent effects against termites.
J K Grace
An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper-chrome-arsenic preservative
1981 - IRG/WP 3150
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. We have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins
Field Testing of Copper Carboxylate Preservatives
2003 - IRG/WP 03-30322
This paper details our ongoing experience with field testing of copper naphthenate and other copper carboxylate preservative systems. Results from field stake tests at an AWPA Hazard Zone 4 test site are presented. In general, copper carboxylates made with ‘synthetics’ yielded results equivalent to or only slightly lower than systems with straight nap acids or nap acids amended with synthetic neo acid bottoms.
H M Barnes, M G Sanders, T L Amburgey
The leaching of copper, chrome and arsenate from CCA-impregnated poles stored for ten years in running water
1978 - IRG/WP 3122
There is no evidence to indicate that the chromium and copper components are leached from the outermost 5 mm of sapwood in poles impregnated with Boliden K33 and Tanalith C and stored in running water for ten years. The arsenic component, however, seems to be leached out during the first few months to an extent of about 20% of the initial amount. The leaching time is dependent on the preservative used.
F G Evans
Problems of fixation of CCA-preservatives in palm-wood
1985 - IRG/WP 3338
Palm-wood may be used for posts and poles where it needs proper treatment for long time use. Based on observations by W. Killmann on low CCA-fixation in palm-wood, samples of Jubaea-palm grown in a Greenhouse at Hamburg, have been treated in two different series with a 4% solution of CCA-type B. After 1-16 weeks of storage the blocks were split into sticks of 1-2 mm² and leached. In all series 50% of the chromium and copper content of the individual blocks was leached independent of the time of storage, whereas simultaneously treated pinewood samples showed complete fixation after 4 weeks of storage.
H Willeitner, K Brandt
A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been elucidated although two oxalate-forming enzymes, oxaloacetase and glyoxylate dehydrogenase, have been studied in our laboratory. Recently, a new role of glyoxylate cycle in oxalate biosynthesis in wood- rotting fungi has been presented, and the cycle commonly occurred to varying extents among the fungi although they were grown on glucose. Enzymatic analyses showed that isocitrate was cleaved by isocitrate lyase in the glyoxylate cycle rather than oxidized by isocitrate dehydrogenase in tricarboxylic acid (TCA) cycle, and the fungi were found to lack a normal TCA cycle due to the absence of - ketoglutarate dehydrogenase. It is noteworthy that glucose was efficiently converted to oxalate in a theoretical yield of about 80%, accumulating in the culture media of F. palustris. The results further indicate that acetyl-CoA derived from glucose was not completely oxidized to CO2 in TCA cycle but was mainly converted to oxalate with help of the other coupling metabolic cycles, including glyoxylate cycle. Formation of oxalate from several intermediary metabolites using cell-free extracts of F. palustris confirmed that oxalate is also the final product of the metabolic pathway in the in vitro system. Thus, it is proposed as a new concept that most of copper-tolerant brown-rot fungi may acquire the energy by oxidizing glucose to oxalate, i.e. oxalate fermentation expressed in the following equation; Glucose + 5O2 --> 2 Oxalate + 2CO2 + 4H2O.
E Munir, T Hattori, M Shimada
Copper naphthenate performance: A new way to look at old data
2000 - IRG/WP 00-30215
Although copper naphthenate has over a 50-year test history, it is still considered as a "new" preservative in the United States when it is used for utility poles. It has also been extensively used in remedial treatments for poles and has considerable retail or over-the-counter sales. The test history includes a number of different tests and a rationale for evaluating this data and comparing the performance of copper naphthenate to other common pole preservatives is presented. Thus, the efficacy of copper naphthenate can be easily summarized.
C R McIntyre
The biostatic effect of copper on decay of fire retardant-treated mining timber
1991 - IRG/WP 1507
Blocks of Eucalyptus grandis were treated with 20kg/m³ ammonium sulphate as fire retardant and challenged with Coriolus versicolor. Replicates were soil buried. A second set of blocks was treated with retardant and copper at 6.6 kg/m³ (ie 1% w/w), and challenged similarly. After 8 weeks weight losses produced by Coriolus versicolor in untreated, retardant treated and copper supplemented blocks were 45, 25, and 0% respectively, and corresponding weight losses in soil were 27, 25 and 10%. These results, and electronmicroscopical observations, showed conclusively that Eucalyptus grandis treated with fire retardant was rapidly decayed, and that copper inhibited such decay.
G D Shelver, E A Shelver, A A W Baecker
Recent soft-rot research in softwoods and hardwoods
1980 - IRG/WP 1108
The purpose of this paper is to describe briefly the current status of our research on soft-rot fungi. The work to be discussed is still in progress and any results described must be regarded as provisional.
J A Butcher
Light organic solvent preservative treatment of glue-laminated radiata pine
1986 - IRG/WP 3380
The high permeability of radiata pine (Pinus radiata D. Don) is associated with ray-tissue and in particular the cross-field pits linking ray-tissue to tracheids. This pathway is absent in the tangential grain direction, leading to poor preservative penetration when treatment is restricted to the radial face - for example, timber fabricated into glue-laminated beams.
Effectiveness and synergistic effects between copper and polymer betaine
1996 - IRG/WP 96-30097
Different formulations of "Copper Amine" and Polymer Betaine were studied. During laboratory tests a synergism between both active ingredients against soft rot and dry rot has been found. The efficacy against soft rot according to the "BAM method" and the European Standard ENV 807 depends only on the amount of copper. Long term tests in a fungus cellar for determining the relative protective effectiveness in ground contact show similar results as CCA-treated wood.
H Härtner, V Barth
Soft rot and bacterial decay in preservative treated eucalypt power transmission poles
1982 - IRG/WP 1155
Bacterial type decay was observed in CCA and PCP treated eucalypt power transmission poles. Detailed observations made with the SEM revealed bacterial colonisation and decay, especially in fibres. Plug samples taken from poles throughout Queensland were examined for preservative retention and presence of soft-rot decay. The severity of decay was different according to location, retention and species.
L E Leightley
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