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Evaluation of wood treated with copper-based preservatives for Cu loss during exposure to heat and copper-tolerant Bacillus licheniformis
1999 - IRG/WP 99-20155
Copper-based wood preservatives need to be effective against exposure to all types of microorganisms. Wood treated with six copper-based preservatives was exposed to 121°C and 20 psi pressure for 15 minutes under standard autoclave conditions and the copper-tolerant bacterium, Bacillus licheniformis CC01, for 10 d at 28°C and 150 rpm. Sixteen to 37 percent of the copper was released from the wood during autoclaving, with copper citrate demonstrating the highest percent loss. Forty-four to 82 percent of the copper remaining in the samples following autoclaving was removed during exposure to the bacterium in liquid culture; copper naphthenate in oil and ACQ-D had losses of eighty percent or greater of the remaining copper. The bacterium removed as much or more total copper in 4 of 6 gas-sterilized samples (85-94%) than the cumulative effects of steam-sterilization and the bacterium on treated samples. Copper loss from in-service treated wood compromises the efficacy of copper-based wood preservatives.
D M Crawford, C A Clausen


Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper tolerant brown rot organism in leaching environments.
S M Gray, D J Dickinson


The effective control of moulds on freshly impregnated wood
2004 - IRG/WP 04-30352
Beside natural timber it is known, that moulds can also groth at the surface of impregnated wood. This material shows “defects” like resistant dark spots or color changes and causes complaints. During the last years, the problem by moulds seems to increase. Laboratory studies were carried out to show the effect of impregnations against moulds. Wood samples (Pinus sylvestris L.) were impregnated by vacuum process using two industrial chromium-free copper based wood preservatives and a CCA-salt. Furthermore fungicides of isothiasoles as “mould-protection-chemicals” were added to the impregnation solutions. To consider an aging effect of this chemicals the modified solutions were stored at temperatures of 20°C or 40°C for 7 days. Direct after impregnation or after 4 weeks of conditioning the samples a mixture of moulds (Aspergillus niger, Penicillium cyclopium, Penicillium funiculosum, Paeciliomyces varioti, Trichoderma viride) were used to infect the impregnated material. The growth of moulds were observed after different times. The intensity of the growth of moulds was different during the first days, but already after 10 to 14 days all samples had complete moulds at the surface. Therefore none of the wood preservatives was protecting the samples against moulds. In the case of sample impregnations using wood preservatives with additional mould-protection-chemicals a various resistance of the impregnated wood on mould infection was found. The resistance depends on the combination of the type of wood preservative and the fungicide used. Differences caused by the aging test could be observed. It can be deduced from these results that this investigation method can help to answer questions concerning necessity, suitability and the appropriate type or content of mould-protection-chemicals in impregnation solutions.
G Cofta, K Lutomski, P Jüngel


Copper based water-borne preservatives: The use of a thin section technique to compare the protection of wood by copper based preservatives against soft-rot and bacterial decay
1987 - IRG/WP 2286
This paper describes the techniques developed and gives examples of results obtained for the performance of copper based wood preservatives against both the bacterial and fungal hazards.
A M Wyles, D J Dickinson


Performance of copper-based wood preservatives in above ground and ground contact tests
1994 - IRG/WP 94-30057
The relative performance of a range of copper-based wood preservatives was compared using above ground and ground contact procedures. The data, accumulated after several years' testing, show that on an equivalent active ingredient basis, differences in performance of the preservative systems tested can vary quite markedly. The contribution of co-biocides to the overall performance of these copper-based systems is discussed.
A F Preston, K J Archer, L Jin, W Metzner, D Seepe


Assessment of the toxicity of some copper-, zinc- and boron-based wood preservatives to the cellar fungus Coniophora cerebella Schröet
1974 - IRG/WP 242
This article reports the use of a method based on the determination of the probability of the protection of timber against destruction by fungi. By converting the probability values to probit values and plotting them as a function of the amount of preservative retained in the timber, curves of the toxic effect are obtained, enabling any timber protection probability to be assessed.
V N Sozonova, D A Belenkov


Experiences with penetration of copper-based wood preservatives
2001 - IRG/WP 01-20233
In the Nordic countries there is a long tradition of result type based specifications for preservative-treated wood. A common Nordic standard for treated pine (Pinus sylvestris) wood was published in 1976. After a revision in 1989 this standard, then named INSTA 140, defined four classes of treated wood: M, A, AB and B. Treaters producing according to this standard had to be affiliated to a quality control and certification scheme. When the European standards EN 351 and EN 599 were to be implemented, the Nordic Wood Preservation Council issued a Nordic application document where the traditional wood preservation classes were defined in terms of EN 351 and EN 599. The present paper describes briefly how the European standards have been implemented in the Nordic countries. During the last years the use of CCA-preservatives has been restricted in the Nordic countries. New copper-based, chromium and arsenic free preservatives have been introduced for commodities above ground. This has by no means been without complications. The treaters have had severe problems to comply with the treatment requirements. Pilot plant treatment trials confirm that the penetrating properties of the chromium/arsenic free preservatives differ substantially from CCA. Experience from the Nordic quality control and certification scheme shows that it is often difficult to judge the penetration of the chromium and arsenic free preservatives. Different copper reagents give different results. A comparative test showed that ammoniumhydroxide and rubeanic acid as reagent for copper was the most sensitive to copper and performed better than other reagents tested.
J Jermer, F G Evans, I Johansson


Serpula lacrymans, The Dry Rot Fungus and its Tolerance towards Copper-based Wood Preservatives
2005 - IRG/WP 05-10555
Serpula lacrymans (Wulfen : Fries) Schröter, the dry rot fungus, is considered the most economically important wood decay fungus in temperate regions of the world i.e. northern Europe, Japan and Australia. Previously copper based wood preservatives were the most commonly used preservatives for pressure treatment of wood for building constructions. Because of a suspicion about tolerance toward copper components, a soil block test was undertaken to clarify the effect of two copper based preservatives, copper citrate and ACQ-D, on the dry rot fungus, Serpula lacrymans compared to an alternative non-copper containing wood preservative. The extensive use of copper-based wood preservatives has hastened the need for understanding why some fungi are able to attack copper-treated wood. The copper tolerance of S. lacrymans and other brown-rot fungi is thought to be due in part to oxalic acid production and accumulation. Oxalic acid has been implicated in copper tolerance by the formation of copper oxalate crystals. Twelve isolates of the dry rot fungus, S. lacrymans and four other brown rot species were evaluated for weight loss on wood treated with 1.2% copper citrate, 0.5% ACQ-D and 0.5% N’N-naphthaloylhydroxylamine (NHA). Eleven out of 12 S. lacrymans were shown to be tolerant towards copper citrate. ACQ-D and NHA, on the other hand, were both effective against the dry rot isolates. These wood preservatives are less toxic toward the environment than traditional copper based preservatives.
A C Steenkjær Hastrup, F Green III, C A Clausen, B Jensen


Observations on the performance of copper-based wood preservatives in fungal cellar (soil-bed) tests
1994 - IRG/WP 94-20047
Fungal cellar (soil-bed) tests are considered to be an important tool for the evaluation of the performance of ground contact wood preservatives. Facilities of this type have been established world wide although caution has been exercised in their introduction into standard testing methods for the approval of wood preservatives. This is the result of concerns over the variability in the biological activity between different facilities, and thereafter the determination of effective preservative retentions. This paper presents results of tests on copper based wood preservatives from four different fungal cellar facilities. The results show consistent trends in preservative performance and the high decay rates demonstrate the value of this type of test in determining the potential of new wood preservatives for long term protection in ground contact.
G R Williams, D Rudolph, M E Hedley, J A Drysdale, R F Fox


Environmental fate of copper-based wood preservatives in different soil substrates - Part 2: Study of the metal sorption and migration potential under simulated rainfall
1998 - IRG/WP 98-50101-21 b
In order to examine the potential environmental impact of spillages of the saltborne wood preservative CCA in treatment plants, four large scale experiments are set-up so as to follow the water transport and ion mobility in various field soils. A plastic container is filled with a sand, silt, clay and potting soil, made up at their respective bulk density and wetted to a given moisture content. Using a rain simulator on top, a homogeneous spillage of a ready-to-use CCA solution is applied, followed by a rainfall simulation after 3 days and a 3 weeks redistribution period. Soil augers that are taken prior to each new perturbance reveal the distribution and migration pattern of the heavy metals. Copper and arsenic are strongly adsorbed in the upper soil layers, depending on the soil characteristics. Chromium, however, is percolated easily through the soil column and is readily extractable from the soil using pure water.
G M F Van Eetvelde, R Hartmann, J M Mwangi, H S Öztürk, M Stevens


Tolerance of Wood Decay Fungi to Commercial Copper Based Wood Preservatives
2002 - IRG/WP 02-30291
Due to the use of copper based preservatives like CCB or CCA for more than a century, copper tolerant fungi have appeared in some European countries in recent times. It is therefore important to find out whether this phenomenon is specific for only classical copper ingredients, or generally for all copper based formulation. Thus, we tested the tolerance of three commercial copper based preservatives and copper(II) sulphate as well as potassium dichromate for comparison. In this research, seven copper tolerant Antrodia isolates and copper intolerant fungus Gloeophyllum trabeum were tested using a screening test and standard laboratory test SIST EN 113. Screening test were performed on potato dextrose agar (PDA) with copper concentration between 5.0×10-4 and 2.5×10-2 mol/l. The tolerance determined by the screening test was not always comparable with results obtained with the standard laboratory test. However, results obtained on wood samples showed that various fungal isolates exhibited different levels of copper tolerance depending on the copper based biocide. Tolerant strains were able to decay copper sulfate as well as copper naphthenate preserved wood samples. On the other hand, even the most tolerant fungi could not decompose wood preserved with classical CCB or copper amine preservative. It can therefore be concluded that various fungal isolates exhibited different copper tolerance regarding copper formulations. This finding is very important for remediation of waste treated wood by fungi. For a successful detoxification of waste wood impregnated with multi salt preservatives like CCA or CCB the suitable tolerant fungal strains have to be used, simultaneously for synergistic action.
F Pohleven, M Humar, S A Amartey, J Benedik


Influence of carboxylic acids on LEACHING of copper amine based preservatives
2005 - IRG/WP 05-30365
The importance of chromium free preservatives is increasing. Leaching of copper from wood preserved with such solutions is still higher compared to leaching from wood impregnated with copper chromium ones. In order to decrease leaching, different carboxylic acids (octanoic, 2-etilheksanoic, decanoic) were added to copper/amine/boron aqueous solutions. Experiment of leaching of copper from Norway spruce (Picea abies) was performed according to the modified standard procedure (EN 1250). Results presented in this paper showed, that carboxylic acids significantly improve copper fixation. The best one was determined at specimens impregnated with the preservative solutions consisting of copper, ethanolamine, boric acid and octanoic acid.
M Humar, P Kalan, F Pohleven


Environmental fate of copper-based wood preservatives in different soil substrates - Part 1: Screening of the metal adsorption potential
1998 - IRG/WP 98-50101-21 a
In treatment plants, spillage of wood preservatives onto soil may be of environmental concern. This potential soil contamination served as an objective for a screening study. Three different mineral soils, a mineral substrate and two horticultural substrates are examined for their sorptive potential of copper through mixing with wood preservative solutions. Depending on the soil/substrate characteristics and the chemical nature of the preservatives used, copper is adsorbed to a higher extent with increasing concentration of the test solution. Soils with low organic matter and clay content show an upper limit of adsorption, irrespective of the product tested. The other soil types clearly exhibit a levelling-out effect from 2 to 4 hours on, often correlating with the initial metal concentration of the product though dependent on the chemical nature and buffering capacity of the active ingredients.
G M F Van Eetvelde, J M Mwangi, F Tack, R Hartmann, M Stevens


Laboratory Evaluation and Field Trial of Chlorothalonil and Copper-based Preservatives and Leaching Performance of Copper in Copper Treated Wood
2002 - IRG/WP 02-30279
Soil block test and field trial of some Chinese plantation wood species pine and poplar treated with chlorothalonil formulations and copper-based preservatives such as ACQ-B and copper citrate (CC) were conducted. The results of soil block test indicated that chlorothalonil formulations and ACQ-B as well as CC are very effective for controlling the 2 fungi species Corious versicolor and Poria placenta at different retention. There is no significant difference of weight loss among retention level range 2.54-23.1 kg/m3 of ACQ-B and CC in our test. The durability of wood treated with chlorothalonil oil formulation is better than that of treated with emulsion formulation. ACQ-B and CC treated wood at different retention level are effectively resistant to decay and termite after 36 monthr field trial at Guangzhou, south China. Leaching rate of copper of CC treated wood is much higher than that of CCA and ACQ-B treated wood by the 2 wood species Pinus massoniana and Eucalyptus urophylla according to AWPA standard M11-87.
Mingliang Jiang, Ping Wang, Chungen Piao, Zhaobang Li, Quan Lu, Lei Liu


Changes of EPR spectra of wood, impregnated with copper based preservatives, during exposure to Antrodia vaillantii
2000 - IRG/WP 00-10355
Spruce wood (Picea abies) samples were impregnated with two different aqueous solutions: copper(II) octanoate with ethanolamine or copper(II) sulfate (cCu = 1,0 x 10-2 mol/l). Impregnated and unimpregnated test pieces were exposed to wood rotting fungus Antrodia vaillantii. Some strains of this fungus are known as copper tolerant. After four weeks of exposure to A. vaillantii, we could not detect any Electron Paramagnetic Resonance (EPR) signal of Cu(II) in the spectrum of copper(II) sulfate treated wood. This means that Cu(II) was translocated or conversed into a form that cannot be detected by EPR. Instead of copper signal, manganese signal appeared. The same, manganese signal appeared also in untreated wood, after exposure to A. vaillantii. On the other hand, line shapes of the EPR spectra of Cu(II) in copper(II) octanoate/ethanolamine treated wood changed by rotting, from anisotropic to isotropic. We believe that these changes are mostly caused by oxalic acid, excreted by A. vaillantii, because we observed the same changes on EPR spectra of impregnated and unimpregnated wood, additionally treated with oxalic acid.
M Humar, M Petric, F Pohleven, M Šentjurc


Copper based wood preservative - A new approach using fixation with resin acids of rosin
2000 - IRG/WP 00-30249
Copper soaps with carboxylic acid groups of resin acids of rosin were shown to be potential long-term wood preservatives. The principle involved is the attachment of copper to the network formed by the inorganic part of the preservative (rosin) through the -COOH groups. The mechanisms of fixation have been studied, and it has been shown that this association could be obtained : (1) by forming the salt (a mix of rosin and NaOH where CuSO4 is added), and then impregnate (with a vacuum/pressure system) the wood with this product dissolved in ethanol, or (2) by using a double impregnation system with water solutions of the mix rosin-NaOH first, and a CuSO4 solution second, the salt being then formed within the timber. The biocidal mechanisms are based on the realease of Cu2+ by hydrolysis of the -(COO - )2Cu2+ when very humid conditions occur, this being reversible when wood moisture content is decreasing. Treated wood mini-blocks have shown good performances when leached, and biological tests assessed the good durability of such treated and leached timber.
C Roussel, J P Haluk, A Pizzi, M-F Thévenon


Leaching Characteristics of Alder Wood Treated with Copper Based Wood Preservatives
2005 - IRG/WP 05-50225
In this study, it was designed for determining leaching characteristics of CCA and alternatives wood preservatives. Alder wood blocks were treated with CCA (1 % and 2 %), ACQ-1900 (2 % and 3 %), ACQ-2200 (1 % and 2 %), Tanalith E 3491 (2 % and 2.8 %), Wolmanit CX-8 (% 1 and 2 %). Leaching studies were conducted according to AWPA E11-97. Copper analyses of leachate were determined Atomic absorption spectroscopy. Results shows that alternative copper based wood preservatives were released higher copper amounts than CCA treated samples.
A Temiz, Ü C Yildiz, E D Gezer, S Yildiz, E Dizman


Fungal degradation of wood treated with metal-based preservatives. Part 1: Fungal tolerance
1996 - IRG/WP 96-10163
In recent years, concerns have arisen about the leaching of heavy metals from wood treated with chromated copper arsenate (CCA), particularly because of the large amount of CCA treated wood that will be discarded in the coming years. The long term objectives of this work are to determine the fate of copper, chromium and arsenic with the aging and potential decay of CCA-treated wood, and to develop strategies for recycling and remediation of disposed wood. In this study, we determined the ability of various decay fungi to decompose southern yellow pine wood treated with CCA or other metal-based preservatives. Isolates of Meruliporia incrassata and an isolate of Antrodia radiculosa caused the highest weight losses in CCA-treated southern yellow pine. One isolate of Meruliporia incrassata produced similar weight losses in CCA-treated and untreated southern pine after 10 weeks. Pine samples treated with very high levels of copper sulphate were decayed by Meruliporia incrassata, but the fungus was unable to decay wood treated with copper napthenate or copper-8-quinolinolate.
B Illman, T L Highley


The Use of Modulus of Elasticity and Modulus of Rupture to Assess Wood Decay in Laboratory Soil-Bed Test
2006 - IRG/WP 06-20338
The efficacy of wood preservatives were determined in a soil-bed test. Samples of alder wood sapwood (Alnus glutinosa subsp. barbata) (5x10x100 mm) were treated with Solutions of CCA (1 % and 2 %), ACQ-1900 (2 % and 3 %), ACQ-2200 (1 % and 2 %), Tanalith E 3491 (2 % and 2.8 %), Wolmanit CX-8 (% 1 and 2 %). Modulus of Elasticity, modulus of rupture, mass loss and decay rate according to AWPA E7 were determined for specimens exposed in soil bed. Results from this study showed that modulus of elasticity can be used to prediction of early stage of wood decay since it is non destructive method.
A Temiz, Ü C Yildiz


Addition of boron compounds and octanoic acid for improvement of biocidal properties and copper fixation at copper-ethanolamine based wood preservatives
2006 - IRG/WP 06-30408
Copper-ethanolamine based wood preservatives became important active substance (formulation) for wood protection, novelty. As copper itself can not ensure sufficient protection against wood destroying organisms and fixation in wood we combine it with other biocides like ethanolamine, boron and octanoic acid. This investigates were performance on spruce wood impregnated with different combination of copper-ethanolamine, boron and octanoic acid in aqueous solution. Copper fixation was determined according to the modified ENV 1250 standard method, while fungicidal testing against Trametes versicolor, Gloeophyllum trabeum and Antrodia vaillantii were performed according to the mini block procedure and termiticidal activity was determined using Kalotermes flavicollis. The results showed that addition of boron increases copper leaching, but on the contrary improves efficacy against wood decay fungi and termites. On the other hand, addition of octanoic acid improves copper fixation, and slightly decreases effectiveness against copper tolerant fungi.
F Pohleven, M Humar


A theoretical-industrial correlation and perspective on copper-based wood preservatives - a review of thermodynamic and kinetic aspects on copper-wood fixation mechanism
2009 - IRG/WP 09-30499
Copper was and it will continue to remain one of the key active component in wood protection industry. Over the past decades, a significant effort from R&D teams in industry, academia and research institutes was directed toward understanding the copper-wood fixation mechanism, optimising the copper retentions in the wood and reduce leaching in order to maximized performance, prolong the lifetime of the treated wood and protect the environment. Significant understanding of copper fixation was achieved in the CCA system, but there are still many uncertainties and grey areas for the newer systems based on copper. Various studies dealing with copper-based systems discussed possible ways to enhance the copper fixation process by either treatment process optimization (e.g. steaming or heating) or by modifying the treatment solution using reactive additives (significant patent activity in this area both from industry and academia). The aim of this study is to review some of the key recent developments and findings on copper fixation mechanism and, starting from a theoretical point of view (thermodynamic and kinetics aspects), identify new possible routes to understand and improve copper-wood fixation in the copper based systems and discuss them also from an industrial/business perspective. The study is also trying to find compelling correlations between various physical and chemical factors and treatment or product parameters which can influence the kinetics of the impregnation process or shift the thermodynamic equilibrium of the copper treatment of wood toward a better copper fixation. The industrial feasibility of these approaches will be reviewed and discussed. As concluding remarks, the study could offer a basis for discussions, new scientific studies, practical and viable approaches to be taken by the wood preservation industry, capable to better understand the copper-wood fixation mechanism, ultimately improving and optimizing the treatment process of wood, and protecting the environment.
R Craciun, M Maier, J Habicht


Influence of wood swelling agents on penetration and copper leaching of copper-ethanolamine based wood preservatives
2011 - IRG/WP 11-30556
Copper ethanolamine based preservatives are currently the most important solutions for impregnation of wood in ground contact in Europe. One of the issues related to those and similar water based solutions is insufficient penetration to refractory wood species like Norway spruce. In order to elucidate this issue, commercial copper ethanolamine based solution was supplemented with five different wood swelling agents (ammonia, ethylene glycol, DMSO, formic acid and triethanolamine) of three different concentrations (2.5%, 5% and 10%). Norway spruce wood specimens were impregnated with those solutions, and uptakes of preservative solutions and depth of penetration was determined. Furthermore, copper leaching according to the ENV 1250-2 procedure was determined as well. The results showed that triethanolamine and formic acid were found very effective and improved penetration of copper ethanolamine wood preservative to wood. On the other hand, addition of those two preservatives increased copper leaching from impregnated wood.
M Humar, N Thaler, B Lesar


Treatability of beechwood railway sleepers with potential creosote substitutes
2017 - IRG/WP 17-40790
Maintenance of an efficient railway infrastructure still requires the use of wooden railway sleepers, particularly because wooden sleepers have more favourable properties for intensified vibrations than concrete or steel sleepers. Creosote, used for decades for the impregnation of railway sleepers, will possibly no longer be available for this application due to European legislation. This reveals the necessity for potential substitutes for creosote. Lab trials, performed in former investigations, proofed the potential of copper amine-based wood preservatives in this field of application. However, so far copper-amine based wood preservatives are mainly used for the impregnation of softwoods and little knowledge is available about impregnation of the hardwood species beech. The tests reported here outline the treatability of beechwood railway sleepers with two copper-based wood preservatives with regard to preservative penetration, retention and distribution. For this purpose beechwood railway sleepers were impregnated with two copper-amine based wood preservatives by vacuum-pressure treatment. Chemical analyses of copper, as distinct active ingredient, revealed an adequate uptake of preservative and a sufficient distribution in longitudinal and transverse direction for both wood preservatives. A slight gradient of preservative retention was detected, with higher retentions in the parts close to the end-grain and slightly lower ones in the middle of the sleeper. Higher preservative uptake was also noticed in the outside margin compared to the inner part of sleepers. However, in all cases, the required minimum uptake of preservative was achieved or, respectively, in most cases, exceeded.
N Pfabigan, E Habla, R Gründlinger


Evaluation of Decay Resistance of Copper-based Preservatives Treated-Wood exposed to different field test sites in Korea
2022 - IRG/WP 22-20679
In Korea, preservative treated wood is required to have a stamp on the surface which contains information such as wood species, use categories, and the company that treated the wood. Such stamping is necessary to safely and appropriately use the treated wood. Since majority of treated wood is being used outdoor environment, the treated wood must have efficacy against wood decay fungi or termite. In order to obtain information regarding the life span of the treated wood (ie, how long does the treated wood can be used safely), resistance on decay and termite attack was evaluated by the indoor and outdoor field tests. In this paper, the outdoor field test results of ACQ-2, CuAZ-2, MCQ, and CuHDO-3 treated woods were reported, which were installed in 2012 and have been monitored for decay resistance. The tests were conducted at 6 different field test sites in Korea, Wood samples treated with various retention levels have been evaluated annually according to the AWPA standards. It was found that the wood treated with lower retentions than the Korean standard were decomposed. However, the wood with higher retentions were still sound to this day. Therefore, it was concluded that the preservative treated wood manufactured following the standard retentions can be used safely for a certain period of time. It is also expected that continuous evaluation and monitoring of the wood in the test sites would enable us to estimate the longevity of treated wood with various retentions.
W-J Hwang, S-M Yoon, Y Park, Y-S Choi, H-M Lee, J-W Kim


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


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