Your search resulted in 17 documents.
A laboratory technique to measure the performance of preservative treated hardwoods in ground contact
1982 - IRG/WP 2172
A laboratory technique to measure the performance of preservative treated timber in ground contact is described. It uses partially sealed blocks of timber which are treated, leached and sawn into small stakelets for soil exposure in a fungal cellar. Performance is monitored by the loss of static bending strength with time, and a simple apparatus for measuring the deflection of a stakelet under a load is described. Birch, Scots pine, and four Eucalyptus species were tested untreated and treated with a CCA preservative. Results show that the wood was attacked by soft rot, that attack could be detected rapidly and accurately using the loss of static bending strength, and that results confirmed field trial and service data. The technique is rapid, simple, accurate and realistic.
E F Baines
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 6: The length of the primary precipitation period
1975 - IRG/WP 359
The end of the primary precipitation fixation period of CCA preservatives coincides with the first peak in pH versus time. This offers a simple way of estimating the duration of the period. The duration is determined by a number of factors and their interactions, the most important of which are: wood species (anatomy, natural pH, accessibility of reducing agents), preservative type, preservative concentration and temperature. For interpretation of experimental data the effect of these factors is discussed in the light of the chemistry and the mechanism of fixation of CCA preservatives. For a proper handling of the treated timber, knowledge of the duration in actual working conditions is essential.
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 4: Conversion reactions during storage
1974 - IRG/WP 332
Precipitates simulating those produced in wood by preservative fixation reactions were prepared by the reduction of Boliden K 33 and Celcure AP solutions with hydrogen peroxide and hydrazine. The pH changes on aging at 20 and 50°C were studied and related to the chemistry of fixation previously described. Hydrolysis of copper arsenates may render arsenic acid temporarily water soluble pending precipitation by trivalent chrome liberated by the slow hydrolysis and reduction by wood of chromic chromates. As the reduction of chrome is the primary driving force for the fixation of Cu-Cr-As preservatives, pH changes were observed in sawdust treated with dilute CrO3 solutions under different temperature cycles. The pH is essentially independent of temperature during the first three days when chromic chromates are being formed, but the subsequent pH is highly temperature-sensitive. Part of this effect is due to hydrolysis and reduction and part to generation of acidic reaction products in the wood at higher temperatures.
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
Resistance to soft rot of hardwood plywood treated with CCA salt
1983 - IRG/WP 3258
Plywood made from indigenous hardwoods was treated at an average loading of 34 kg Celcure A per m³ and was installed in a field test. After 20 years the samples were only slightly attacked by soft rot and the glue bonds were still intact.
R S Johnstone
Fungicidal and termiticidal effectiveness of alkylammonium compounds
1983 - IRG/WP 3232
This paper is related to effectiveness of several AAC's against wood decay fungi and termites by Japanese standardized test methods.
K Tsunoda, K Nishimoto
Soft rot decay of 23 CCA-treated hardwoods from Sabah, Malaysia, in ground contact in Australia
1986 - IRG/WP 1280
The performance against soft rot decay of 23 CCA-treated hardwoods from Sabah, Malaysia, was examined after 20 months in ground contact at Pennant Hills, Australia. The results indicate that between these species soft rot decay is excluded by different levels of CCA salt suggesting that the threshold level for exclusion of soft rot in these hardwoods is a function of anatomical structure/ultrastructure.
R S Johnstone
The effect of ACC (Celcure) on durability of blue beech
1999 - IRG/WP 99-30209
Durability of the sapwood and heartwood of blue beech (Carpinus betulus) against white rot fungus (Coriolus versicolor) was studied. As treatment three concentrations of preservative (control or 0%, 3%, and 5% of ACC) were applied. The measuring 1.5x2.5x5cm3 as dimension of wood samples (sap and heartwood) was used. During 16 weeks exposure, untreated wood blocks were completely deteriorated by the fungus and their weight losses were 24.4% in sapwood and 23.4% in heartwood. However, 3% and 5% of ACC caused that weight losses were significantly decreased. In 3% of preservative sapwood decreased only 1.08%, and heartwood reduced 0.94%. In 5% of ACC weight losses were 0.97% (sapwood) and 1.03% (heartwood). Thus there was a significant difference between treated and untreated wood, and no significant differences were occurred between sapwood and heartwood when exposed to the white rot fungus.
S M Kazemi
An interim report on trials with 'Boliden K33' and 'Celcure A' in water of different salinities in the Baltic Sea and in the UK
1974 - IRG/WP 406
It was felt necessary to undertake field trials using large test samples exposed in natural water of different salinity in order to determine preservative leaching and to assess the degree of biological attack.
R A Eaton, D J Dickinson
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
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
Investigation of temperature effect on fixation of Celcure preservative (ACC) in beech (Fagus orientalis)
2001 - IRG/WP 01-40200
In this research, the fixation speed of Celcure 2% (ACC) preservative salt, under temperature of 17°C, 27°C and 50°C, on intact and stained wood specimens of beech was investigated. For this purpose, blocks of wood with 5x5x7 cm dimensions were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. For measuring the percentage of fixation through time, the specimens were extracted by using hydraulic pressure equipment, under 69 Mpa pressure. The pH of extraction was measured with the method of diphenyl Carbazid and by using spectrophotometer. This measurement was done continuously and the amount of 6- valence chromium concentration present in the extract was compared with the amount of chromium concentration in the primary solution and then the percentage of fixation was calculated. The results showed that the decrease in 6-valence chromium is accompanied with increase of pH, this is due to absorption of positive hydrogen ion by 6-valence chromium for reduction to 3-valence chromium and also ion-exchange of active components with wood during the primary phase of fixation. Also, the time necessary for reaching complete fixation in intact and stained wood in the fixation temperature conditions of 17, 27 and 50°C were 1075, 501, 109 hours, respectively. In general, the results showed that temperature has effective role in accelerating of fixation process and in this respect, intact and stained wood did not show significant statistical difference.
A Karimi, M Ghorbani
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 3180
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. The growth characteristics of spruces (Picea spp) make them attractive candidates for forestry schemes. In 1975 the UK Forestry Commission had about 400 000 hectares, about 20% of total UK forest area, planted with Sitka spruce (Picea sitchensis). As an example of the situation in Scandinavia, the growing stock in Sweden consists of about 45% Norway spruce (Picea abies), 38% Scots pine (Pinus sylvestris) and the remainder hardwoods. The importance of spruce as a source of sawn timber in Europe is clear and we are investigating methods of improving the treatment of this timber. As part of the investigation we have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins
Inadequacies in preservative retention and formulation as contributory causes of premature failure of CCA-treated vineyard posts
1984 - IRG/WP 3280
Analyses of severely decayed or failed vineyard posts and examination of stake test data on effectiveness of copper-chrome-arsenate (CCA) preservatives have suggested two contributory causes of premature failure of vineyard posts: 1. Preservative retentions in posts are such that after 15 years' exposure some decay is inevitable. 2. The high arsenic, low chrome formulations with which the posts were treated are less effective in controlling decay than low arsenic high chrome formulations previously used in New Zealand, on the performance of which many concepts of CCA effectiveness are based.
M E Hedley
Corrosion of fasteners in treated wood
1971 - IRG/WP 303
Surveying tests for determining the corrosion rates of some metals and alloys in wood untreated as well as treated have been made. It is shown that ordinary steel corrodes faster than other common fastener metals such as copper, brass, aluminium and stainless steel do. Zinc coatings, however, will prevent the steel corrosion effectively provided that the coatings are thick sufficiently. Catalytic decomposition of cellulose by rusting iron is briefly discussed since the expectation of life for a fastener joint is not only depending on after the corrosion remaining cross-section of the fastener but also from the wood deterioration.
The performance of metal-chromium-arsenic formulations after 32 to 38 years' in-ground exposure in Australia
2000 - IRG/WP 00-30240
Two trials of metal-chromium-arsenic preservatives were exposed in-ground in Australia. In Trial 1, Pinus radiata stakes treated with Boliden K.33, Boliden S.25, Celcure A, Tanalith C and Tanalith CA were installed at Sydney and Narrandera in 1961/1962. In Trial 2, P. radiata and Eucalyptus regnans sapwood were treated with Celcure A, Celcure A21-N, Celcure A 21-O and Tanalith CA (new) and installed at Sydney and Innisfail in 1966/1967. In Trial 1, all metal-chromium-arsenic preservatives at 8 and 12 kg m-3 gave median specimen lives in excess of 35 years. As none of the stakes treated to 12 kg m-3 with Boliden K.33, Celcure A, Tanalith C or Tanalith CA had become unserviceable, the minimum guarantee period for these preservatives is greater than the present exposure periods. In Trial 2, the four CCA preservatives when impregnated into P. radiata sapwood at 12 kg m-3 gave median specimen lives at Sydney of greater than 32.5 years. With E. regnans sapwood treated to 12 kg m-3, only Celcure A 21-0 gave a median specimen life at Sydney of greater than 32.5 years. At the high decay and termite hazard site of Innisfail, Celcure A 21-0 protected the eucalypt better than any of the other CCA formulations.
G C Johnson, J D Thornton, J Beesley
Investigation of temperature effect on fixation of Celcure preservative (ACC) in Hornbeam (Carpinus betulus I)
2003 - IRG/WP 03-30304
In this research, the fixation speed of Celcure 2 % (ACC) preservative salt, under temperature of 30 ºC, 40 ºC and 50 ºC on intact wood specimens of hornbeam was investigated. For this purpose, blocks of wood with 2Í 2 Í2 cm dimensions of hornbeam were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. For measuring the percentage of fixation through time, the specimens were extracted by using hydraulic pressure equipment, under 70 Mpa pressure. The PH of extraction was measured with the method of Diphenyl Carbazid and by using spectrophotometer. This measurement was done continuously and the amount of 6-valence chromium concentration present in the extract was compared with the amount of chromium concentration in the primary solution and then the percentage of fixation was calculated. The results showed that the decrease in 6-valence chromium is accompanied with increase of PH, this due to absorption of positive hydrogen ion by 6-valence chromium for reduction to 3-valence chromium and also ion –exchange of active components with wood during the primary phase of fixation. Also, the time necessary for reaching complete fixation in intact wood in the fixation temperature conditions of 30, 40, 50 ºC were 98, 52, 24 hours, respectively. In general, the results showed that temperature has effective role accelerating of fixation process.
R Imani, R E Majdar, A Karimi