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Effect of fatty acid removal on treatability of Douglas-fir
1993 - IRG/WP 93-40008
Treatment of Douglas-fir with chromated-copper-arsenate (CCA) poses a major challenge. Several hypotheses based on the anatomical aspects as well as chemical reactivity of the preservative formulations with cell wall constituents and deposits have been proposed. Techniques to prevent pit aspiration or slow fixation reactions have, however, not significantly improved treatment. The presence of high molecular weight fatty acids have been reported to be responsible for higher hydrophobicity in some wood species. These acids can react with Cu+2/Cr+3 ions to form insoluble metallic soaps, thereby immobilizing Cu/Cr and increasing wood hydrophobicity by a mechanism similar to that employed in paper sizing. The effect of fatty acids on treatability was explored by removing these components via several extraction methods. In general, extracted wood had higher gross solution absorptions and chemical retentions, but preservative penetration was largely unaffected. The results suggest that removal or disruption of fatty acids can improve treatability of Douglas-fir heartwood.
S Kumar, J J Morrell


Rapid leaching test
1991 - IRG/WP 2367
An accelerated test which is suitable for measuring the extent of metal fixation in both chromium and non chromium containing preservatives is described.
J A Cornfield, M Bacon, A Lyman, C Waldie, M R Gayles


Fixation of CCA in Pinus sylvestris after kiln-drying
1990 - IRG/WP 3594
Tanalith C Paste is 98% fixed and Tanalith Oxide C is 99% fixed irrespective of whether treated Pinus sylvestris is kiln or air dried. A schedule suitable for kiln drying of CCA treated Pinus sylvestris is described.
P Warburton, J A Cornfield, D A Lewis, D G Anderson


Leaching of CCA components from treated wood under acidic conditions
1993 - IRG/WP 93-50004
The leaching of CCA components from treated wood under acidic conditions were investigated. Western hemlock treated with three types of CCA and two levels of target retention was subjected to leaching at four different levels of pH. After leaching tests, leached samples were subjected to laboratory decay and soft rot tests. The amount of CCA components leached was dependent on acidity of leaching solution, CCA formulation, and target retention. The leaching of CCA components at pH 4.0 or above was not significant even though a relatively low amounts of arsenic were leached. The resistance of leaching according to the type of CCA was in the sequence of CCA-Type C (oxide), CCA-Type C (salt) and CCA-Type B (oxide). The amount of leaching was increased with the increase in target retention. The reduction of biological effectiveness was not distinct for treated wood leached in acidified water of pH 4.0 or above. Based on the results of this study, it might be concluded that losses of CCA components at pH 4.0 or above were not great enough to cause public concern about environmental problems and reduction of biological efficacy in service.
Jae-Jin Kim, Gyu-Hyeok Kim


Comparisons of differences in electrical conductivity and corrosivity between CCA-oxide and CCA-salt treated wood
1981 - IRG/WP 3178
CCA preservatives have served well in many applications throughout the world. In developed areas it is the preservative in demand for clean dry paintable surfaces with long durability. In developing areas it is widely used for economic and logistical reasons. With the current emphasis on energy resources, the CCA preservatives are gaining greater acceptance as a substitute for hydrocarbon-related preservatives. While there are several formulations with apparent wide differences in the proportions of active ingredients, (chrome, copper and arsenate), the performance of each appear to be essentially equivalent as wood preservatives. This performance has lead to an almost blind acceptance in the market place in the U.S. in that any CCA is considered equivalent in all respects. When all aspects are considered, it is readily apparent that this equivalency does not exist.
J A Taylor


Leaching of Arsenic from Mulch Made from Recycled Construction and Demolition Wood
2005 - IRG/WP 05-50232
Mulch made from recycled construction and demolition (C&D) wood has been reported to contain chromated copper arsenate (CCA)-treated wood and potentially release arsenic in the leachate by rainfall. Such recycled wood mulch is commonly masked with iron-oxide colorant, which is known to combine with arsenic. The objective of this study was to evaluate the levels of arsenic leaching from C&D recycled wood mulch and potential effects of the colorant on leaching rates. Mulch samples observed were paired (dyed and non-dyed) in three groups [untreated wood, 5 % treated wood, and 100 % treated wood]. The leachates were collected for one year and analyzed for arsenic. Arsenic in the leachate from untreated wood mulch was consistently at low levels (< 3 ~ 13 ug/L). The average concentrations from 5 % treated wood mulch were 341 (non-colored) and 258 &#956;g/L (colored). The average concentrations from 100 % treated wood mulch were 4,490 (non-colored) and 3490 &#956;g/L (colored). For the entire one year monitoring period, the colorant reduced the arsenic concentration by 24 and 29 % for the non-colored 5 % treated wood mulch and 100 % treated wood mulch, respectively. The study showed that recycled C&D wood mulch, which contains small percentages of CCA-treated wood, release significantly large levels of arsenic by rainfall and iron oxide colorant reduces the arsenic leaching rate for a short period.
T Shibata, H M Solo-Gabriele, T G Townsend, B Dubey


Influence of CCA and TnBTO on wood decay, under different oxygen levels and various initial moisture content
2001 - IRG/WP 01-10415
Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) were impregnated by TnBTO (tributyl-tin oxide) and CCA (chromated copper arsenate). In wood blocks two levels of moisture content (50% and 100% of saturation point) were used. Three levels of oxygen concentrations (10, 21, and 50%) were chosen. Treated and untreated wood were exposed to three fungi (C. versicolor a white rot, C. puteana, a brown rot, and C. globosum a soft rot). The results showed when TnBTO was used and wood samples exposed to C. versicolor between treated (TnBTO) and untreated specimens was no a big difference in weight losses. Using high moisture content (100%) in wood blocks caused very low weight losses in all treatments to be appeared. When CCA was applied decay by C. puteana was very decreased in Scots pine, therefore, there was a large difference in weight losses between treated and untreated wood. Low oxygen and high moisture content in treated samples caused wood decay by C. puteana did not occur. In the case of C. globosum effect, increasing the moisture content caused that wood decay in all specimens (treated and untreated) to be increased. However, low oxygen concentration in middle moisture content (50% SP) increased decay in beech.
S M Kazemi, R J Murphy, D J Dickinson


Tropical In-Ground Durability of Structural Sarawak Hardwoods Impregnated to High Retention with CCA-salts, CCA-oxide and FCAP after 20 Years Exposure
2005 - IRG/WP 05-30384
Statistical analysis (ANOVA) was conducted on durability (termite and decay combined) rating data collected over 20 years exposure period of over 140 species of Sarawak timbers with altogether 30,000 stake specimens, at the Forest Department’s Sibu “graveyard” stake test sites from 1977. About 20 replicated stakes were pressure-treated to refusal with 10% g/ml concentration of up to 3 CCA-salt formulations and 1 CCA-oxide product and FCAP were visually evaluated every 6 months according to the 5-point ASTM D1758 durability rating scale, and the treated durability results reported in this paper are between 5 and 20 years exposure. The analysis was confined to 7 relatively high density hardwood species that are regarded suitable for in-ground structural use (ie, basic density >600 kg/m3), and had achieved a minimum preservative retention of 16 kg/m3 (as required for CCA-salts) but up to 48 kg/m3 retention. The results revealed that the in-ground durability of treated wood decreased usually after 5 years to poor-to-moderately durable levels with CCA-salts, moderate-to-high durability with CCA-oxide, but failed with FCAP after 20 years. CCA-oxide treated hardwoods out-perform the CCA-salt treated counterparts despite their relatively similar retention and “over-treatment factor”. The non-leach-resistant FCAP is clearly unsuitable as an industrial used in-ground wood protectant.
Wang Choon Ling, A H H Wong


CCA type C depletion of Southern yellow pine utility poles
1995 - IRG/WP 95-50049
Depletion and redistribution of preservative components were evaluated on five CCA-C treated poles in service for over six years in Conley, Georgia. A statistical approach was taken in which retentions below ground were compared to retentions above ground due to a lack of initial data on individual poles. It was hypothesized that the below ground retentions should be lower than the corresponding above ground retentions based on the premiss that wood in ground contact is subject to a higher leach potential than wood above ground contact. There were no significant differences between above ground and below ground CCA-C retentions in any of the six 12.5 mm zones. Linear regression performed on the retentions across zones showed no significant difference between the slopes of the gradient curves on either exposure for any of the components indicating there has been no redistribution of chemicals among zones.
P D Osborne, R F Fox


The susceptibility to sludging of sulfate and oxide CCA
1990 - IRG/WP 3599
Radiata pine sapwood was treated separately with a sulphate CCA-C and an oxide CCA in a pilot scale pressure plant using a full cell process. CCA solutions were recovered from the final vacuum phase, placed in plastic tubes, and their susceptibility to sludging determined by examining changes in solution pH, time required for sludge to form and weight and chemical composition of sludge formed. Sulphate CCA-C solutions showed a pH rise of 0.33 above the initial solution pH of 2.01 and a sludge, largely composed of arsenic and chrome, formed after 6-8 weeks. Oxide CCA solutions in contrast showed smaller pH changes and did not form sludge. Addition of glucose or ethanol to freshly prepared sulphate CCA-C and oxide CCA solutions at 25°C resulted in sludge formation with both formulations but sludge formed earlier and in greater quantities with the sulphate CCA-C. The results indicate that the oxide CCA is more resistant to sludging than the conventional sulphate CCA and suggest that the use of the former in treatment plants could reduce sludge formation. Further methods to minimize sludge formation in treatment plants are also discussed.
B T Mutandadzi, P D Evans


Effectiveness of MOQ® OX 50 (CCB-Oxide) wood preservative – Part 2: Field tests
2008 - IRG/WP 08-30483
MOQ® OX 50 is a chromated copper borate preservative known around the world as CCB. In Brazil, this product is the only CCB-oxide type preservative with fungicide and insecticide properties registered at the Brazilian Institute for the Environment and Renewable Resources (IBAMA) that complies with the requirements of the Brazilian and European markets for preserved wood. For over five decades, salt-based CCB preservatives have been used in Brazil with good results. However, with the objective of further improving its performance and minimize precipitates normally observed in salt-based formulations, from 1998 onwards Montana Química S.A. started manufacturing this product exclusively with oxide-based raw materials. The assessment of the effectiveness of this preservative when wood treated with it is exposed to the tropical environmental conditions prevailing in Brazil is of fundamental importance to ensure a cost-effective alternative to CCA-C preservatives. Therefore, the objective of this paper is to present the results of the performance assessment of CCB-oxide and CCA C-oxide preservatives carried out in field tests and compare their effectiveness. These results complement those of the soil-block and leaching tests presented at the 5th Wood Protection National Congress (Cidemco), held in San Sebastian, Spain, June 2008. MOQ OX ® 50 es un borato de cobre cromatado, preservante para madera conocido en todo el mundo como CCB. En Brasil, es el único preservante fungicida e insecticida del tipo CCB ÓXIDO con registro en el Instituto Brasileño de Medio Ambiente y de los Recursos Naturales Renovables (IBAMA), acatando a todas las exigencias de los mercados brasileño y europeo de preservantes para maderas. Por más de cinco décadas el producto CCB (borato de cobre cromatado) base salina tiene sido utilizado en Brasil con buenos resultados. Todavía, buscando mejorar su desempeño y reducir al mínimo la formación de residuos normalmente notadas en las formulaciones salinas, Montana Química comenzó a fabricarlo, a partir de 1998, utilizando exclusivamente productos óxidos como materias-primas. El estudio del comportamiento de ese preservante en exposición a condiciones ambientales brasileñas (tropical y subtropical) es de gran importancia, para ofrecer al mercado una alternativa válida de bajo costo al producto CCA-C. Así siendo, este trabajo tiene el propósito de presentar resultados de la evaluación de desempeño comparativo en campo de los productos CCB óxido y CCA-C óxido. Estos resultados complementan los ensayos soil-block y lixiviación presentados en el 5 º Congreso Nacional de Protección de la Madera (Cidemco), realizado en Junio 2008 en San Sebastián - España.
A Gandolfi Jr, C Salvela, D R Macedo, J M Vidal


A comparison of soft rot, white rot and brown rot in CCA, CCP, CCF, CCB, TCMTB and benzalkonium chloride treated Pinus radiata IUFRO stakes, after 9-15 years exposure at five test sites in New Zealand
1991 - IRG/WP 1485
The aim of this study was to determine if decay type varies significantly between five field trial test sites of different soil type, aspect and climate in 9-15 year old, replicate CCA, CCF, CCP. CCB, TCMTB and AAC treated IUFRO stakes. A visual on-site assessment of decay type on every test stake was made and observations confirmed by microscopical examination. Regression analyses were used to determine significant differences of percentage frequency of occurrence of each rot type between sites and preservatives. Large differences in percentage frequency of occurrence of rot type were evident between sites. One site was dominated by brown rot (85%) and two were dominated by soft rot (99 and 91%). The fourth site had intermediate proportions of brown rot (40%) and soft rot (71%) but had the second highest occurrence of white rot (32%) (highest = 37%; lowest = 11%). The fifth site was distinct in that a large proportion of stakes (69%) had both well established brown rot and soft rot. Stakes at the other four sites tended to have only one rot type. Some highly significant preservative effects were also found. Possible causes of these differences are discussed in terms of inter-site soil type, climate and other differences.
R N Wakeling


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 2: Report of treatment and installation in Australia
1978 - IRG/WP 440
The purpose of this test and the procedures to be followed have been fully set out in documents distributed by the International Research Group on Wood Preservation and numbered IRG/WP/414 and IRG/WP/420. The prescriptions set out in these two documents have been closely followed.
J Beesley


Marine testing of selected waterborne preservatives
1987 - IRG/WP 4137
In 1978 a marine test was established at West Vancouver, B C. to determine the performance of selected waterborne preservatives. The preservatives in test were chromated-copper-arsenate (CCA-C), ammoniacal copper arsenate (ACA), a modified formulation of ACA which contained a higher copper content (modified ACA), ammoniacal copper zinc arsenate (ACZA) and ammoniacal zinc arsenate (AZA). The wood species used for the test was red pine. After eight years in test the CCA is providing excellent performance at all retentions, while the modified ACA is showing significant deterioration only at the lowest level. The ACA is performing quite well although it shows signs of surface deterioration at all retention levels. The performance of the ACZA is rated as unsatisfactory at retentions below 32 kg/m³ while AZA was considered to be unsuitable for use in the marine environment.
J N R Ruddick


Manual of a mini treating plant for waterborne preservative treatment of timber and bamboo
1999 - IRG/WP 99-40130
This contributional article includes machinaries and equipments necessary for a small wood treating plant for the pressure treatment of tim bers with waterborne preservatives along with the cost and design. The preservative treatment limitations, treatment schedules and specifications for different products have been described. The cost of a mini treating plant will be 6,00,000 Tk. (13,000 US$), suitable for preserving timber and bamboo products for indoor and outdoor uses and will out last teak wood. The additional durability of timber and bamboo will create economically and environmentally safe conditions.
A K Lahiry


Fire resistance of preservative treated fence posts
1994 - IRG/WP 94-30033
Pine fence posts were pressure treated separately with CCA-C, CCA-wax, CCA-oil and creosote. Treated posts and untreated controls were planted in the ground in a randomised block design, weathered for six months and then subjected to a controlled burning test using two fuel loads. Creosote treatment increased the time that posts were alight whereas CCA treatment had no such effect. However, CCA treated posts smouldered until destruction of the majority of the posts occurred. Posts treated with CCA-oil took longer for destruction to occur than posts treated with CCA-C or CCA-wax. Creosote treated posts and untreated controls did not show prolonged smouldering and consequently were not destroyed by the burning test, although their strength was reduced. A high fuel load increased the time that posts were alight and smouldering, and for CCA treated posts decreased their time to destruction.
P D Evans, P J Beutel, C F Donnelly, R B Cunningham


Strength loss associated with steam conditioning and boron treatment of radiata pine framing
1987 - IRG/WP 3438
The combined effect of included defects and wood moisture content on the strength loss of second rotation radiata pine framing following conventional steam conditioning is investigated. The green Modulus of Elasticity (MOE) is reduced by approximately 13% after steaming. When dried after steaming, however, neither the MOE nor MOR is significantly different from unsteamed dried controls.
M J Collins, P Vinden


Collaborative soft rot tests: PRL tests of Cu/Cr/As preservative using method of Document No: IRG/WP/208
1973 - IRG/WP 223
These tests were undertaken as a preliminary to the next series of collaborative soft rot tests. An interim report has already been presented at Berlin in 1972 as Document No: IRG/WP/211
J K Carey, J G Savory


Japan's comments on ISO/DIS 12583-1/2
1996 - IRG/WP 96-20100
The paper describes an accelerated field test for the evaluation of timber preservative formulations against subterranean termites. The method has been adopted by the South African wood preservation industry as a screening method for the approval of wood preservatives for use under SA conditions. The method which is based upon the fungal cellar test offers a rapid means of evaluating the comparative performance of new wood preservative formulations in an environment that accurately reflects field conditions.
P Turner, D Conradie


Soft rot in CCA-treated utility poles in Sweden
1989 - IRG/WP 1398
Soft rot investigations of CCA-treated utility poles (Pinus sylvestris L.) have been conducted throughout large parts of Sweden during 1974-1985. The investigation included 179 utility poles of the State Power Board which had been used for 10-18 years in the different administrative regions from northern to southern Sweden. In addition, 193 telephone poles from the Östersund area and 218 from the Kristianstad area were studied after having been in use for 18-25 years. The soft rot fungi cause two types of attack in wood cells, namely cavities (Type I) and erosion (Type II). In this investigation, soft rot is reported only when cavities of Type I were found. Erosion (Type II) is more difficult to observe, particularly in early stages, and in addition is almost impossible to distinguish from certain other attacks of rot, such as white rot, which may have occurred during storage of the poles before impregnation. In western and central Sweden, minor attacks of soft rot were found after 10-12 years in State Power Board poles embedded in soil in arable land and meadows. Power Board poles in northern Sweden had minor attacks of soft rot after 16-18 years in arable land and also in forest land when embedded in soil. Poles used by the Telecommunications services, all embedded in stone, showed minor and only occasional attacks of soft rot at Östersund (northen Sweden), but considerably more soft rot at Kristianstad (southern Sweden). The Telecommunication poles had been in service up to seven years longer than the poles used by the State Power Board. The localization and spread of soft rot attacks in a pole can vary. There may be many reasons for this, including insufficient impregnation, leaching, etc. The soft rot attacks found in the Power Board poles are always minor and sporadic and none of the investigated poles can be said to imply any safety risk. The same applies to the Telecommunication poles at Östersund whereas those at Kristianstad demonstrated considerably more severe and more frequent attacks. The attacks of soft rot in the Telecommunication poles more frequently occurred internally, more often deeper in the sapwood than in the outermost parts.
H Friis-Hansen, H Lundström


Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh


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


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. 2nd Interim Report
1981 - IRG/WP 477
Three reference wood species - Alstonia scholaris, Fagus sylvatica and Pinus sylvestris, untreated and treated with 3%, 6% and 10% CCA and CCB solutions were supplied to all participants for submergence at local sites. Regular examination of samples is being carried out - 6 months, 12 months and then annually for 7 years.
R A Eaton


Non-pressure treatability of plywood by CCA, CCB and boron
2005 - IRG/WP 05-40295
Study on diffusibility and absorbability of CCA, CCB and boric acid in 3 mm thick 3-ply hardwood plywood at water saturated and air-dry conditions and dipped at same concentration (5%) and same duration of time (12 hours) revealed complete diffusion of all the preservatives at water saturated condition. Only the CCA-C was found absorbed by the plywood at air-dry condition. The rate of absorption and diffusion of CCA-C was found about 4.5 times higher than CCB and boric acid.
A K Lahiry


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


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