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Copper fixation in ACQ-D treated Chinese fir at various temperature and relative humidity conditions
2007 - IRG/WP 07-30436
In this study, the effect of different conditions of temperature, relative humidity, and duration of post-treatments on accelerating copper fixation in ACQ-D treated Chinese fir wood blocks was investigated. The conditions include the combination of three temperatures (21, 50, and 70?) and two relative humidity levels (20% and 80%), also include four temperatures (50, 70, 90, and 110?) without controlling relative humidity. The results showed that: (1) all post-treatments used in this study can reduce copper leaching from ACQ-D treated wood. The percentage of copper leached out decreased linearly with the duration of post-treatment at a certain temperature and relative humidity condition; (2) temperature has a significant effect on accelerating copper fixation in ACQ-D treated wood. The fixation rate is much higher and the predicted time needed for complete copper fixation is much shorter at higher temperatures; (3) relative humidity has little effect on fixation rate, and has varying effect on predicted time needed for complete fixation. It shows obvious effect at low temperatures and tends to disappear at high temperatures.
Jinzhen Cao, Lili Yu
Accelerated fixation of ACQ-D treated Chinese fir with different post-treatments
2008 - IRG/WP 08-40400
With the enhanced focus on the environmental impact of the preservative-treated wood in recent years, it is necessary to perform some post treatments to prevent contamination of soil and ground water and reduce copper losses from ACQ treated wood in service. In this study, the potential of hot air, hot water, steaming and microwave post treatments to accelerate the fixation of copper in ACQ-D treated Chinese fir were assessed. The results showed that: 1) all post-treatments used in this study could reduce copper leaching from ACQ-D treated Chinese fir. For hot air and hot water post treatments, the percentages of copper leached out were highly temperature and duration dependent, and were reduced significantly with increased temperature and duration. For hot air post treatment, higher relative humidity and circulation conditions accelerated copper fixation in wood. At 70°, 10h hot air post treatment at 80%R.H. with circulation conditions or 100° hot water post treatment for 9h, most of the copper in the treated wood could be fixed in the Chinese fir wood samples. However, for steaming and microwave post treatments, it seemed the duration and temperature or power level only slightly accelerated copper fixation in wood. 2) During hot air post treatments, a very small proportion of cupric copper was converted to cuprous forms at higher temperatures. However, during 100° hot water post treatments, cupric copper was quickly reduced to cuprous forms and it was highly duration dependant. The percentage of copper conversion could be more than 40% after 9h in 100° hot water. Further studies will be carried out: a) to evaluate promising conditions to improve copper leaching resistance in steaming and microwave post treatments; b) to assess the copper conversion after steaming and microwave post treatment for which better leaching resistance could be obtained.
Lili Yu, Jinzhen Cao, P A Cooper
Tensile stress relaxation of wood impregnated in different ACQ formulations at various temperatures
2009 - IRG/WP 09-40456
The reactions between ammoniacal copper quat (ACQ) constituents and wood components were investigated by tensile stress relaxation approach. Small wood samples were stressed and impregnated in ACQ solutions with different formulation including the ethanolamine (MEA) to copper molar ratio, copper (as copper oxide) to quat (as DDAC) weight basis, treatment temperature and also the solution concentration, and during this period the stress relaxation curves were recorded. The effect of different parameters mentioned above on stress relaxation of wood was investigated by orthogonal experiment design (OED). From the stress relaxation curves, some information concerning the reactions between ACQ constituents and wood was obtained since the formation of chemical or physical bonding between ACQ and wood would both release the stress produced in wood and then accelerate the stress relaxation process. The results showed that the stress relaxes dramatically in the initial period and then change slightly even within a long period. There are two reaction mechanisms predicted from the slopes of the regression lines obtained from the double logarithmic plots of modulus f (t) versus time (t) in the initial period of stress relaxation, which are defined as Phase I and PhaseⅡ. They correspond to physical and chemical processes respectively. The molar ratio of Cu to MEA and treatment temperature take the significant effects on the rate of reaction on Phase I, while on Phase Ⅱ, the significant factor is only the treatment temperature based on the results of range and variance analysis. It reveals that although the competitions among ACQ constituents existed, the adsorption of copper is still the major reaction in the wood.
Lili Yu, Jinzhen Cao
Effects of Cunninghamia Lanceolata Heartwood Extracts on the Growth of Wood Decay Fungi
2010 - IRG/WP 10-30527
China-fir (Cunninghamia lanceolata) wood is well known for its good durability. This species is native to China and has been extensive planted there. Mainly, extractives are responsible for the wood resistance to decay fungi. In this paper, the extractives of China-fir heartwood were studied for their effects on various wood decay fungi. Sequential extraction of heartwood in hexane, ethyl acetate and methanol resulted in 0.8, 1.0 and 2.8 % (w/w) recoveries, respectively. Both of fourier transform infrared spectroscopy (FTIR) analysis and high performance liquid chromatography (HPLC) analysis revealed that hexane extractives were primarily aliphatic compounds, methanol extractives were mainly phenolic in nature and ethyl acetate extracts contained both aliphatic and aromatic compounds. Gas chromatography-mass spectrometry (GC-MS) analysis clarified that cedrol and cedrol acetate represented approximately 47 % of the hexane extract. Phenol content analysis showed that phenols took up 22.8% of the methanol extract and the extract’s free radical scavenging capacity was close to that of butylated hydroxytoluene (BHT), which is a commercial antioxidant. In vitro bioactive tests showed that none of the three extracts were strongly inhibitory to cultures of Trametes versicolor, Gloeophyllum trabeum, Aspergillus niger or Paecillomyces variotii. These results suggest that the combination of extractive fractions rather than any single compound, is important for China-fir durability. Soil block tests showed that non-extracted heartwood blocks were resistant to T. versicolor but experienced substantial weight loses when exposed to G. trabeum. Weight losses increased in hexane extracted blocks, but then declined markedly in those ethyl acetate extracted blocks. The results suggest that either residual solvent in the material inhibited the white rot fungus or the extraction process altered available phenol content to limit the ability of the fungus to attack wood.
Shujun Li, Jing Wang, Jian Li
Evaluation of ACQ-D treated Chinese fir and Mongolian Scots pine with different post-treatments after 20 months of exposure
2010 - IRG/WP 10-30530
The performance of alkaline copper quat-type D (ACQ-D) treated Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) stakes after 20 months exposure in Chengdu and Guangzhou of southern China were evaluated according to AWPA standard E07-07. The ACQ-D treatments used two concentration levels (0.5 and 1.0%) and four different post-treatments (air drying for 1 month, conditioning at 70°C, 80% R.H. for 24h, oven drying at 110°C for 24h, boiling in water for 15h), respectively. The field test results showed that the natural durability of Chinese fir is a little better than Mongolian Scots pine but the untreated sapwood stakes of both wood species were mostly destroyed after 20 months exposure. After ACQ-D treatment, the sapwood of both wood species showed much better biological performance. Among the four post-treatments, the oven drying method (OD) rated the worst by showing slight reduction in biological performance and the most obvious reduction in compression strength after exposure, while the other three post-treatments performed similarly. It suggested that both post-treatments of HC (conditioning in humidity chamber) and HW (hot water bath) could be good selections for accelerating copper fixation in ACQ-D treated wood. And also, Chinese fir from plantation forests could be a potential wood species for preservation.
Lili Yu, Jinzhen Cao, Wei Gao, Haitao Su
Application of radio frequency heating to accelerate fixation of CCA in treated round-wood
1999 - IRG/WP 99-40133
The potential of radio frequency heating to accelerate the fixation of chromated copper arsenate (CCA) in treated round-wood was assessed. Pre-dried Douglas-fir and western red cedar round-wood sections were pressure treated with CCA in a pilot plant retort, after which they were placed individually in a pilot radio frequency (RF) chamber. Based upon the color reaction of chromotropic acid with hexavalent chromium and the quantitative assessment using diphenyl carbazide, fixation was achieved in less than 6 hours. During heating, the temperature at various locations inside the pole sections was monitored by fiber-optic thermocouples. The moisture profiles before, and after fixation, were also recorded. Further studies will examine other benefit of RF heating, including a) sterilization, and b) rapid drying of round-wood with minimum check formation.
Fang Fang, J N R Ruddick
Treatability of plywood containing intermountain Douglas fir veneers
1982 - IRG/WP 3203
Eighteen sheets of plywood were obtained which contained intermountain Douglas-fir veneers from two regions of British Columbia. Following pressure treatment with chromated copper arsenate (CCA type C) and ammoniacal copper arsenate (ACA) the preservative penetration and retention in individual veneers was assessed. It was concluded from the study that the intermountain Douglas-fir veneer could not be adequately penetrated by either CCA or ACA, although the degree of penetration achieved with ACA was better than that recorded for CCA. The preservative retentions measured were generally in excess of that required for plywood to be used in the preserved wood foundation system.
J N R Ruddick, A Walsh
Gloeophyllum trabeum and Gloeophyllum abietinum, the most frequent brown rot fungi in fir wood joinery
1999 - IRG/WP 99-10319
In Croatia the primary raw material for joinery production is silver fir wood (Abies alba Mill). L-joints made of home-grown fir sapwood and prepared according to EN 330: 1993 were used to establish the infection and colonisation of micro-organisms, particularly wood decay fungi, to compare the performance of untreated and 1% TnBTO treated L-joints. The L-joints were coated with two types of coat, and 36 months exposed in Zagreb. The first type of coat was alkyd paint and the second was a stain, in three different colours: white, brown, and black. The influence of the preservative, and the type of coat were most important factors which affected the rate of colonisation. The influence of coat colours was significant at the the beginning of exposure. The fastest and the strongest colonisation occurred in untreated L-joints coated with alkyd paint and the lowest colonisation occurred in treated L-joints coated with stain. It was due to the well known vaporous diffusivity of the stains and the low natural permeability of fir sapwood. The most frequently isolated fungi were Gloeophyllum trabeum (Pers.: Fr.) Murr. and Gloeophyllum abietinum (Bull.: Fr.) Karst.
R Despot, M Glavas
Effect of a penta emulsion on the service life of Douglas fir, heartwood posts
1978 - IRG/WP 3112
C S Walters
Movement of boron from fused boron rods implanted in Southern pine, Douglas fir, red oak, and white oak timbers
1995 - IRG/WP 95-30061
This paper reports the distribution of boron from fused boron rods installed into six-inch (15.2 cm) square timbers of Douglas-fir, Southern Pine, red oak and white oak exposed aboveground. The composition and size of rods was: sodium borate and sodium borate-copper oxide (8.5 x 100 mm²); sodium borate-copper, sodium borate and boric oxide-copper oxide (12 x 76 mm²). The boric acid equivalent was roughly monitored by the curcumin/salicylic acid color test and the presence of copper was detected by the chrome azurol-S reagent. One year after installation of rods, movement of boron was determined by application of curcumin dye to increment cores removed at various distances from the site of boron rod installation. A portion of a sodium borate treated Southern Pine timber was also analyzed by spraying curcumin dye on sawed longitudinal and transverse sections. At 2 years, one foot sections were removed from all timber species, sawed as above, and boron and copper detection reagent sprayed on the sawed surfaces. Movement of copper from rods in all timbers was virtually nil. Both transverse and longitudinal movement of boron from rods was greatest in Southern pine which also had the highest moisture content. Movement of boron was next best in red oak. There was little movement of boron away from the rods in white oak and Douglas-fir.
T L Highley, L Ferge
Long-term effectiveness of fumigants in controlling decay in Douglas fir waterfront timbers
1986 - IRG/WP 3364
The persistence, movement, and effectiveness of chloropicrin and Vapam (sodium N-methyl dithiocarbamate) in large, horizontal Douglas fir timbers were evaluated 7 years after fumigation. Chloropicrin prevented reestablishment of decay fungi; reinvasion occurred in some Vapam-treated timbers. Residual fungistatic effect was detected up to 1.2 m from the fumigation site in chloropicrintreated timbers but not in Vapam-treated timbers.
T L Highley
A behaviour of CCA penetration of fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications
2006 - IRG/WP 06-40346
A behaviour of CCA penetration of Bornmulleriana fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications was illustrated for the main flow directions by the experimental pictures.
I Usta, R Despot, M Hasan
Above ground performance of CCA-treated fingerjointed lumbe
1993 - IRG/WP 93-40003
Studs made from short lengths by finger jointing are becoming more commonly used in North America. Recently Forintek has received enquiries about the performance of such material in a treated form. Treated and untreated nominal 2x4 inch² spruce-pine-fir (SPF) studs exposed above ground for 12 years in southwestern British Columbia were evaluated for evidence of decay. Despite shallow preservative penetration, which did not meet North American standards, the CCA-treated material showed no signs of decay. In contrast two of the 30 untreated samples had failed and the mean rating was 1.3 on a 0 to 4 scale. These results are encouraging for the use of CCA treated SPF as finger jointed or conventional lumber in above ground exposure.
P I Morris, G E Troughton
Sequential exposure of borate treated Douglas-fir to multiple Formosan subterranean termite colonies in a 40-week field test
1993 - IRG/WP 93-10006
Douglas-fir boards (ca. 74.5 g) pressure-treated with disodium octaborate tetrahydrate (DOT) retentions of 0 (controls), 0.88, 1.23, 1.60, or 2.10% (weight/weight) DOT were sequentially exposed to four active field colonies of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in an above-ground field test. Samples were placed in contact with each colony for 10 weeks, with oven-dry weight losses determined between exposures, for a total termi exposure period of 40 weeks. Feeding activity differed among termite colonies, with the control wood samples having mean weight losses of 1.3-15.1% of their initial weight during each individual 10-week termite exposure. The two lower borate retentions (0.88 and 1.23% DOT) were virtually equal efficacy, with mean wood weight losses during each individual 10-week exposure ranging from 1.2-4.6%. Feeding was negligible at the two higher borate retentions, with mean wood weight losses from termite feeding during each 10-week period ranging from 0.7-1.3% with 1.60% DOT, and 0.3-0.9% with 2.10% DOT. Total cumulative wood weight losses over the 40 week exposure were: 10.2% (0.88% DOT), 8.7% (1.23% DOT), 3.6% (1.60% DOT), and 2.4% (2.10% DOT).
J K Grace, R T Yamamoto
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
Studies on the biological improvement of permeability in New Zealand grown Douglas fir
1983 - IRG/WP 3231
This report outlines progress towards optimizing conditions for water storage of New Zealand grown Douglas fir with the aim of improving permeability to water-borne preservatives, in particular CCA. Small scale laboratory tests are in progress but the need to scale up to potential commercial applications is being considered. Mixed populations of bacteria isolated from 10 week water sprinkled Douglas fir are being used to inoculate green, sterile timber. Environmental parameters such as pH, temperature and nutrient status are controlled to evaluate optimum conditions of growth, enzyme production and pitmembrane degradation leading to permeability improvement.
K J Archer
Evaluation of Barrier Wrap Systems after 71 Months of Exposure
2013 - IRG/WP 13-40631
A 71 month study of the performance of booted samples in ground contact was conducted in AWPA hazard zone 4. Data indicated that excellent performance of wrapped systems, even over untreated wood, could be obtained. Instances of decay colonization or termite attack could all be attributed to some breaking of the integrity of the barrier system. Good performance for treatment below ground contact threshold was demonstrated.
H M Barnes, M G Sanders, G B Lindsey, C McIntyre
Treatment of Douglas fir heartwood with disodium octaborate tetrahydrate (Tim-BorÒ ) to prevent attack by the Formosan subterranean termite
1991 - IRG/WP 1487
Toxicity of disodium octaborate tetrahydrate (Tim-BorÒ) to Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), and termite feeding on treated Douglas-fir heartwood were evaluated in laboratory and field tests. Feeding on filter papers impregnated with Tim-BorÒ solutions reduced but did not eliminate termite gut protozoan populations. In a forced-feeding laboratory assay, Douglas-fir heartwood treated to Tim-BorÒ retentions ³0.35% BAE drastically reduced termite feeding and resulted in 100% termite mortality within three weeks. Gradual and significant mortality (49%) after four weeks of feeding at 0.16% BAE suggests that this or lesser concentrations may be useful in baits for remedial termite control. After 162 days of field exposure to an active Coptotermes formosanus colony in an accelerated field test, moderate feeding was noted at 0.65% BAE (13.6% weight loss) and 0.73% BAE (16.9% wt. loss), and only slight damage (2.5% wt. loss) at the highest retention field tested of 1.02% BAE. These results indicate that Tim-BorÒ provides protection from Formosan termite attack, but that some cosmetic damage occurs even at high retentions. This cosmetic damage is unlikely to create a structural hazard, but additional field evaluations are needed to determine the treatment requirements for timbers visible to the consumer.
M Tamashiro, R T Yamamoto, J K Grace
Development of decay in untreated, second-growth Douglas-Fir using two exposure techniques in North Queensland
1997 - IRG/WP 97-20110
The results of two exposure techniques for evaluating the development of wood decay in untreated, mill-run lumber from second-growth Douglas-fir containing both sapwood and heartwood are presented. Nominal 50 mm by 100 mm by 2.5 m (2 in. by 4 in. by 8 ft) lumber, No 2 and better, was obtained from a production run in a mill that was processing second growth, Coastal Douglas-fir in western Oregon, USA. Untreated wood members were kiln dried, then shipped to Queensland. At the Timber Research Laboratory, Indooroopilly, Queensland, two units for above-ground exposure were fabricated from each 2.5-m (8-ft) untreated member. A 600-mm (2-ft) length was cut from each end of each member. One 600-mm section was transversely bisected, forming two, 300-mm (12in.) units; the other 600-mm section was used in a separate study. The middle 1200-mm (4-ft) length was used as one exposure unit. These shorter members were then milled to form a joint with a 100-mm (4-in.) overlap. Two holes were drilled through the overlapping portions, and the two sections were bolted together. The identity of the 1200mm length and the end-matched lapped jointed section was maintained throughout the exposure. Both units were positioned on a horizontal support approximately 1 m above ground in an open field near Innisfail, Queensland. As units were installed in the field, all cut surfaces inside the joint and at the ends were brush coated with a commercially available (in Australia) copper naphthenate emulsion containing 1% copper. Decay was first detected after 2 years of exposure and it advanced rapidly during the third year. The pattern of results suggests that the weathering of the upper, exterior surface and the retention of a high moisture content by the 50-mm-thick wood, when wetted, is more important in predisposing wood to decay than is end-grain absorption of moisture. Decay ratings for the 1200-mm members were equivalent to those observed with the lapped joints. The two types of units are of equal utility in demonstrating the potential for decay in a wood material that has natural susceptibility to decay.
J Norton, S Kleinschmidt, R C De Groot, D Crawford
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
The effect of selective additives and conditions on the decomposition of Basamid in Douglas fir heartwood
1992 - IRG/WP 92-3698
Basamid is a solid, powdered chemical used as an agricultural soil fumigant. Decomposition of Basamid isothiocyanate, hydrogen sulfide, methyl amine, and formaldehyde. Basamid has some potential as a wood fumigant, but it decomposes too slowly to be effective. Various additives and conditions were tested for their ability to enhance Basamid decomposition in Douglas-fir heartwood. Higher MC's and temperature, as well as copper sulfate and powdered pH 12 buffer increased decomposition rates with copper increasing the efficiency of breakdown to form MITC.
P G Forsyth, J J Morrell
Soft rot decay of Eucalyptus maculata Hook. in different soils from Queensland, Australia
1980 - IRG/WP 1113
In the present work, different Queensland soils were chosen and their gross effects on the decay of treated and untreated Eucalyptus maculata examined. The soils were also amended with various levels of phosphate to study the response of the wood decay mycota to an increasing supply of this nutrient. Phosphate amendment was chosen because of the wide-scale use of superphosphate on Queensland soils and the importance of inorganic phosphate in the carbohydrate metabolism of microorganisms.
L E Leightley, I W Russell
Effect of incising depth and density on treatment of Douglas fir, hem fir and spruce-pine-fir lumber with CCA, ACZA or ACQ
1997 - IRG/WP 97-40093
Incising markedly improves both the depth and uniformity of preservative treatment of refractory wood species, but there are few studies directly comparing the effects of incising depth and density on penetration and retention of commonly used waterborne preservatives in wood species from the western United States. The effects of two incision densities (7300 and 8900 incisions/square meter) at two depths (5 and 7 mm) were investigated using two strength classes of Douglas fir, hem fir and spruce-pine-fir lumber. In general, grade or strength class had no significant effect on treatability. Treatability markedly improved with increasing incision depth, while increased incision density produced less tangible results. Ammonia-based treatments were associated with deeper penetration reflecting the ability of the heat and/or ammonia to improve preservative penetration. Further studies are underway to evaluate the effects of incising and subsequent preservative treatment on strength properties.
M Anderson, J J Morrell, J E Winandy
Movement and persistence of Dazomet and pellected methylisothiocyanate in wrapped Douglas fir and southern pine timbers
1991 - IRG/WP 1496
The movement and persistence of Dazomet (tetrahydro-3,5-dimethyl-2 H-1,3,5 thiadiazine-6-thione) and pelleted methylisothiocyanate (MIT) was evaluated in wrapped Douglas-fir and Southern Pine timbers. MIT pellets did not impart a fungistatic effect to any of the timbers. Failure of MIT was probably due to loss of MIT from pellets prior to application. Fungistatic effect of Dazomet was consistently detected at 0.3m from the treatment center but effect beyond this distance was variable. Fungistatic effect was detected at 2 years after Dazomet treatment in Southern Pine but not at 3 years. Fungistatic effect was still present in Douglas-fir timbers at 3 years.
T L Highley
A Soil Bed Test of the Effect of CCA Penetration on the Performance of Hem-fir Plywood
2004 - IRG/WP 04-30332
An accelerated decay test was set up to compare the performance of CCA-treated Western hemlock/amabilis fir plywood treated to meet the preserved wood foundation (PWF) retention standard with various patterns of preservative penetration. Short lengths of treated plywood and comparable untreated material were installed in a soil bed. After eleven years of exposure, the CCA treatments were all sound regardless of penetration, while the untreated material had failed due to decay within three years.
P I Morris, J K Ingram