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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

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

Boron dual-treatments for Douglas-fir utility poles: Tracking boron migration over time
2019 - IRG/WP 19-30739
The potential for using boron pressure-treatment prior to over-treatment with conventional, heavy-duty wood preservatives to limit internal decay in-service was investigated in two field tests on Douglas-fir utility poles. Pole sections were pressure-treated with disodium octaborate tetrahydrate (DOT) and then over-treated with either pentachlorophenol or copper naphthenate in oil. Alternatively, poles were treated with a mixture of DOT and ammoniacal copper zinc arsenate in a single treatment. The pole sections were installed in the field and monitored for changes in boron content over time. Boron levels immediately after treatment were extremely high in the outer 25 mm of poles in both tests and declined sharply away from the surface. Field exposure for one to five-years resulted in some boron losses near groundline, but overall levels near pole surfaces remained well above the fungal protection threshold. Diffusion did occur further inward, but there was still a steep boron gradient from the pole surface five-years after treatment. Results are discussed in the context of Douglas-fir heartwood resistance to boron diffusion compared with other wood species and the potential for long-term retention of chemical within the heartwood.
J Cappellazzi, M J Konkler, J J Morrell

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

Reticulitermes lucifugus Rossi, and its damages in Turkey
1982 - IRG/WP 1152
The moist-wood termite, Reticulitermes lucifugus Rossi, is generally observed on the wood material which has a direct contact with the soil as trunks and fence stakes. It was reported to be found in some provinces in Turkey. The termite has been seen in these areas so far at the endemic level, but any considerable damage or epidemy has not yet been reported. Considerable damages were observed on the fibreboard stored under unsuitable conditions at Artvin fibreboard factory during the depression period of building sector in the years of 1980-1981.
O A Sekendiz

Report of meetings of remedial treatments Sub-group held in Madrid, Spain during 27-28 April 1988
1988 - IRG/WP 3502
J N R Ruddick

Examen chimique du traitement de poteaux effectué à St-Michel s/Meurthe
1974 - IRG/WP 337
J Guillemain-Thévenot, C Jacquiot

Metal carboxylates for wood pest control
1996 - IRG/WP 96-30109
Metal carboxylates have been used as wood preservatives for more than fifty years. Predominantly salts of naphtenic acids have been commercially applied so far. They have water repellent as well as fungicidal and insecticidal properties. In the last years, metal carboxylates of saturated fatty acids were introduced. Fatty acids with 7-10 carbon atoms already have fungicidal activity by themselves. However, their efficacy is markedly increased in a complex with metal ion such as copper and zinc. This carboxylates are environment friendly and low toxic for humans. We studied fungicidal, insecticidal and termiticidal effectiveness of copper and zinc carboxylates by European standard methods. The strongest fungicidal and insecticidal activity showed copper and zinc naphtenates and copper octanoate. The metal octanoates are soluble in white spirit and, moreover in aqueous ammonia solutions. One day after treatment, the leaching of some carboxylates from wood was very low. These carboxylates did not increase the flammability of treated wood.
F Pohleven, M Petric

Literature survey on the permanence and distribution of salt-type wood preservatives
1969 - IRG/WP III 1B
The objective of this survey is generally to review some of the more important published work dealing with the distribution and permanence of salt-type waterborne wood preservatives in treated timber. The survey is limited to the major chrome-containing formulations and the classification system proposed by Becker (1964) has been adopted throughout. CK - chromium, copper (copper, chrome); CKA - chromium, copper, arsenic (copper, chrome, arsenate); CKB - chromium, copper, boron (copper, chrome, boron); CFK - chromium, fluorine, copper (copper, chrome, fluorine); CFA - chromium, fluorine, arsenic (fluor, chrome, arsenate); CF - chromium, fluorine (fluor, chrome). The literature compilation covers the performance of these preservatives assessed from laboratory tests, field tests and practical experience; their application and distribution in the treated wood; and their influence on materials such as glues, paints or metals and the wood itself. It is not the purpose of this survey to draw conclusions regarding the relative merits of the various formulations, the choice of a formulation in a given situation depending upon many factors outside the terms of reference of this review, and not all of a technical nature. In general, there is insufficient directly comparable data for a definitive assessment and in the few comparisons available special factors frequently apply.

Migration of Metals from Douglas-fir Lumber Treated with ACZA or Pentachlorophenol Using Best Management Practices: Preliminary Tests
2005 - IRG/WP 05-50224-4
The potential for migration of preservative components from ammoniacal copper zinc arsenate (ACZA) and pentachlorophenol treated Douglas-fir lumber in non-soil contact exposure was assessed in a simulated rainfall device. Metal levels from ACZA treated wood were elevated for the first 30 minutes of rainfall and then declined sharply. Repeated cycles of rainfall led to declines in initial metal losses suggesting that surface metals were gradually depleted from the wood. Penta losses were also initially high, but then declined at rates related to rainfall level. The results suggest that preservative losses from treated wood in above ground exposures can be predicted.
J J Morrell, Hua Chen, J Simonsen

Water-borne preservative marine trials in Western Canada
1981 - IRG/WP 470
Red pine boards treated with chromated copper arsenate, ammoniacal copper arsenate, copper zinc arsenic additive, a modified ammoniacal copper arsenate, and zinc arsenic additive, have been installed in a marine field test at West Vancouver, British Columbia. After two and a quarter years exposure, all the test samples are in excellent condition with the exception of those treated with the zinc arsenic additive. All the zinc arsenic additive treated boards at the lowest preservative retention and two thirds of those at the second lowest retention in test have failed. A performance index calculated for the zinc arsenic additive indicates an added service life of 3% at the standard retention level.
J N R Ruddick

Chemical analyses of IRG/COIPM INTERNATIONAL MARINE TEST (to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water) samples
1987 - IRG/WP 4114
Chemical analysis of CCA and CCB treated timber was carried out after exposure at tropical and temperate marine sites. Results indicated that losses of all elements had occurred. In particular, losses of boron were severe. Arsenic and copper were also lost. The chromium components in both formulations was the most dominant metal remaining. The results suggest that chromium modification was important in timber treatments for the marine environment, since there appeared to be little difference in timber protection between the CCA and CCB systems.
L E Leightley

Durability of wood in the area of wood-inhabiting termites in Slovenia
1981 - IRG/WP 1139
This report describes a research dealing with resistance and durability of five different species of wood. The experiment was made in natural conditions in the Slovene area of wood-inhabiting termites. The results of our experimental field, which correspond to the results of the former laboratory experiments, show a very weak resistance of spruce-wood, fir-wood, and beech-wood. They also show their short durability /up to two years/, if they are exposed to all natural external influences. Pine wood shows a better resistance; the most resistant of them is oak-wood. However, the results of the experimental field indicate a possibility of prolonging the durability of these species of wood by a preventive protection made by chemicals.
L Kervina

A Preliminary Report on the Properties of Engineered Wood Composite Panels Treated with Copper Naphthenate
2005 - IRG/WP 05-40294
This paper reports on our preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate (CuN) incorporated into the board during manufacture. When compared to zinc borate-treated controls (ZnB), the mechanical properties of strandboard (MOR, MOE, work-to-maximum load, internal bond strength) were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls > waterborne CuN = powdered CuN > ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites.
J W Kirkpatrick, H M Barnes

Leaching and fixation characteristics of chrome-copper-fluoride-zinc (CCFZ) treated wood
1996 - IRG/WP 96-30096
The leaching characteristics of radiata pine sapwood blocks treated with CCFZ were evaluated by the AWPA standard leaching test. The rate of fixation of the preservative components in CCFZ treated radiata pine were also evaluated by quantitative analysis of solution expressed from the treated wood. Both leaching and fixation characteristics of CCFZ were compared with CCA-Type C treated wood samples. The permanence of CCFZ is excellent and comparable to that of CCA-Type C, and the rates of CCFZ fixation were similar to those found for CCA-Type C. These results suggest that CCFZ has a potential as alternative preservative for the replacement of CCA-Type C.
Gyu-Hyeok Kim, Jong-Bum Ra

Applications of the shower test. Part B: Results from CC and CCB treated wood: influence of fixation process
1993 - IRG/WP 93-50010
This report outlines the results of shower tests conducted on CC and CCB treated wood. The results indicate the fairly good fixation of chromium and the reasonable fixation of copper in CC and CCB formulations, as judged by the leaching limits within the Environmental Regulations. In general boron leaches to a higher extent than chromium and copper. The shower test has proven to be a useful quality control and research test. It determines reasonably accurately the leaching under simulated conditions and, admittedly from a limited number of tests, it can determine differences between various fixation cycles. Natural fixation, controlled climate room fixation and steam fixation were compared. Overall the sleam fixation process gave the lowest leaching figures although the selection of an appropriate fixation facility is a question for individual companies, taking into account capital, customer base, throughput etc.
W J Homan, H Militz

Diffusion of a copper naphthenate/boron paste through Douglas fir heartwood
1991 - IRG/WP 3671
Groundline wraps are an important portion of the remedial treatment strategies for protecting utility poles in North America from surface decay. The compositions of these wraps have recently shifted away from pentachlorophenol and creosote to formulations containing copper naphthenate and boron. These formulations have not yet been extensively tested, although the chemicals have been used for many years in other applications. Radial and longitudinal diffusion of the components of a copper naphthenate/boron paste was studied in Douglas-fir heartwood blocks at 30 and 60% moisture content. Longitudinal orientation and higher moisture levels resulted in greater diffusion of both components. Boron diffused faster than copper naphthenate over the 6 month test period, but the degree of copper movement was substantial. The results suggest that this copper/boron paste can readily diffuse through normally refractory heartwood. Field trials are underway to evaluate the biological efficacy of this formulation.
P G Forsyth, J J Morrell

Corrosion of zinc-coated nails used with preservative-treated western red cedar shakes in service
1982 - IRG/WP 3197
The corrosion of metal fasteners used with certain wood species and with preservative-treated woods can be a serious problem. The chemical reactivity of western red cedar (Thuja plicata Donn) extractives to iron and copper is well documented and wood preservative treatments containing copper, chromium, and/or ammonium hydroxide can be expected to similarly attack some metals. This problem is compounded when red cedar is treated, and, such treatments with CCA and ACA have become customary in current efforts to extend the service life of shingles and shakes. Present recommendations for shake and shingle roof applications specify the use of hot-dipped zinc (iron) or aluminium nails. However, the use of nails made of stainless steel or other alloys of greater cost is advised with preservative-treated wood products.
R S Smith, E L Johnson, A J Cserjesi

Susceptibility of CCB treated wood to fungal colonization
2003 - IRG/WP 03-10492
CCB treated wood is generally resistant to all wood decay fungi. However, like CCA impregnated wood, susceptibility of CCB treated wood to copper tolerant fungi have been observed. The ability of various brown rot fungal hyphae to penetrate and overgrow the wood samples was investigated. Samples made of Norway spruce (Picea abies) were impregnated with 5 % CCB solution according to the EN 113 procedure. After conditioning, part of the samples was leached according to the EN 84 method. Small stick of unimpregnated wood (r = 1.5 mm, l = 25 mm) was inserted into a hole, bored in the center of the samples, and after that sealed with epoxy coating. Sterilized, leached and non-leached impregnated and unimpregnated specimens were exposed to two copper-tolerant (Antrodia vaillantii, Leucogyrophana pinastri) and two copper sensitive (Poria monticola, Gloeophyllum trabeum) brown rot fungi for one, two or four weeks. After exposure, the inserted wood pieces were removed from the specimens and put onto nutrient medium in petri dishes. Growth of the hyphae from those wood pieces was then visually determined. Rate of colonization by the fungi were determined by measurement of CO2 production. After that, mass losses of parallel specimens were also determined. The fastest colonization of the unimpregnated specimens was by G. trabeum (one week). On the other hand, no fungal growth could be detected on non-leached CCB impregnated specimens even after four weeks of exposure. However, significantly more intense colonization by the copper tolerant fungi were detected on the leached CCB treated samples.
F Pohleven, U Andoljsek, P Karabegovic, C Tavzes, S A Amartey, M Humar

Natural exposure weathering tests: Their role in the assessment of wood preservative efficacy
1993 - IRG/WP 93-20006
Previous work has demonstrated the potential and usefulness of natural ageing procedures in e evaluation of wood preservative efficacy. This results from the combination of physico-chemical influences and microbiological interactions with both substrate and wood preservative. In this paper, results are presented for a range of biocide types. Discussions are centred on the value of natural exposure weathering tests for preservative efficacy assessment and the importance of biological persistence in the design of effective wood preservatives.
G R Williams, J Brown

Fungicidal activity of some new water borne copper octanoate based formulations
1999 - IRG/WP 99-30198
Four new water borne formulations for preservation of wood were prepared: the composition of Cu(II) octanoate, 2-aminoethanol (ethanolamine) and water; the composition of complex of Cu(II) octanoate with nicotinamide, 2-aminoethanol and water; the one of Cu(II) octanoate, organic boron complex, 2-aminoethanol, dimethyl sulfoxide and water and finally, the mixture of Cu(II) octanoate, diazene, 2-aminoethanol and water. Fungicidal activity of these new formulations against Trametes versicolor, Antrodia vaillantii and Coniophora puteana was determined by filter paper and mini-block test methods. Compared to the commercially used wood preservative containing Cu(II) naphthenate / Cu(II) 2-ethylhexanoate, the new compositions have stronger fungicidal activity. The strongest biocidal activity was exhibited by the formulation with a Cu(II) octanoate/nicotinamide complex.
M Petric, M Pavlic, F Pohleven, P Segedin, B Kozlevcar, S Polanc, B Stefane, R Lenarsic

Laboratory evaluation of metallic naphthenates as wood preservatives
1991 - IRG/WP 3654
Fungicidal and termiticidal efficacy of copper and zinc naphthenates was appraised according to Japanese standardized laboratory testing methods. Copper and zinc naphthenates succeeded in protecting wood from decay fungi at retentions of 0.5 and 1.0 kg/m³ as metal, respectively. [JIS A 9302 (1976)] when they were applied to vacuum/soak impregnation [JIS A 9301 (1976)]. With respect to the fungicidal performance in superficial treatment, copper naphthenate was sufficiently effective at a treating strength of 2% as Cu and zinc naphthenate was at 3% as Zn after mild weathering cycles prescribed in JWPA Standard 1 (1979). Their termiticidal effectiveness was satisfactory at 1-2% in wood block tests [JWPA Standard 111) (1981)] in which Pine sapwood specimens treated by brushing were exposed to subterranean termites for three weeks.
K Tsunoda, M Sakurai

Inorganic preservatives in wood dust - Cause of nasal cancer?
1997 - IRG/WP 97-50085
Since 1985 dust particles from beech and oak trees have been classified by the Senate Commission of the German Research Council (DFG) as being ,,working materials which are definitely carcinogenic to humans". All other wood dusts, including those from softwoods, are classified as being materials ,,with reasonable suspicion of carcinogenic potential". The carcinogenic principle of action continues to remain unclear despite some partial findings of new studies. The load of wood dust with non-genuine chemicals especially heavy metals is one of a number of possible triggering principles. This study describes wood dust collected in 33 German wood processing companies, with regard to concentration of the dust in the air and load of the dust with chromium, copper and boron. More often than expected the machining of preservative treated wood was found. Besides wood preservatives other sources of contamination of wood dust have been identified. Woodworkers are exposed to higher levels of chromium, copper and boron than average citizen, but are far away from threshold values. The heavy metal exposure levels found seem to be unlikely the sole carcinogenic principle of action.
A O Rapp, K Brandt, R-D Peek, U Schmitt

Relative performance of copper/chrome/boron (CCB) and copper/chrome/arsenate (CCA) in ground contact
1992 - IRG/WP 92-3694
The performance of four retentions each of an oxide CCA formulation and a salt formulation of CCB in radiata pine and European beech was compared after 18 years' field exposure. In radiata pine CCA oxide was more effective (4 failures out of 40) than CCB (9 failures out of 40). However, in European beech CCB was substantially more effective (22 failures) than CCA oxide (all failed). Analysis of failed stakes showed that up to 85% of arsenic had been lost from below ground portions of CCA oxide-treated beech stakes compared with 75% of boron from CCB-treated beech stakes. Percentage losses of copper and chromium were less.
M E Hedley

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

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