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The effect of pretreatments on the impregnation of air-dried sawn Belgian spruce
1988 - IRG/WP 3490
In general the impregnation of airdried spruce results in a variable treatment and limited penetration. This is the result of pit aspiration that occurs during drying of the spruce sapwood and heartwood. Spruce timber is becoming of greater importance in Belgium and hence research for better treatment of this vulnerable wood species is needed. Squared airdried timber of different dimensions were extracted from 10 winter-felled logs (Picea abies (L.) Karst) and impregnated with preservative used for constructional purposes. Partly the material was presteamed or waterlogged. Prior to the preservative treatment both groups were reconditioned to the same moisture content as the reference material (airdried). Retention and different penetration parameters showed better figures when only modifying the treating cycle rather than using a pretreatment. Both pretreatments seemed to have no positive effect on the treatability of airdried material. Increasing the strength of the initial vacuum parameters of the full-cell processes improved the degree and homogenity of the penetration of the preservative components.
J Van Acker, M Stevens


Preservative treatment of green timber by soaking in ammoniacal copper borate
1984 - IRG/WP 3292
Freshly sawn boards of radiata pine sapwood were preservative treated by soaking in ammoniacal copper borate. Optimum schedules were obtained by partially seasoning the boards for one week prior to treatment. This aided the absorption of preservative and reduced the required soaking time to approximately 2 hours. Complete boron penetration was obtained after one week of block storage under cover and air drying. Copper penetration was more limited because of fixation of copper. The preservative treatment system should have particular application in the treatment of coconut timber destined for above-ground use but exposed to the weather.
P Vinden, A J McQuire


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


The Effect of Heat on the Retention of Ammoniacal Copper Quat (ACQ-AB) onto Scots Pine (Pinus Sylvestris L.) Wood
2008 - IRG/WP 08-40390
In this study, the sapwood of Scots pine (Pinus sylvestris L.) were treated with ammonical copper quat type (ACQ-AB), which is one of the environmentally friendly wood preservatives, by using soaking method as a functions of various temperatures and time. The results indicated that the retention behaviour of ACQ onto the wood was considerably affected by temperature of ACQ solution and treatment time.
M Hakki Alma, A Mukremin Kara


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


EPR investigations of interactions between ammoniacal Cu(II) octanoate and wood
1996 - IRG/WP 96-30110
Ammoniacal solutions of copper(II) octanoate [ C u . h l f . 2 . r h l f.(O2CC7H15)4], interactions of these solutions with wood and wood components, and leaching of copper(II) octanoate from impregnated wood samples, have been studied by electron paramagnetic resonance (EPR) method. It is still not clear if in the Cu(II) octanoate - water - ammonia system, Cu(II) remains in a (copper(II) octanoate - ammonia) complex. The majority of leached Cu(II) with distilled water and a solution simulating acid precipitations was washed out in the first five hours of leaching procedure (up to 35% of initial Cu(II)). Time dependence studies of interactions of ammoniacal Cu(II) octanoate with wood, cellulose and brown rotted lignin showed, that the fastest and most significant was the reaction with lignin. Cu(II) is immobilised also on cellulose. A significant contribution of ammonia evaporation to the fixation mechanism of the preservative was observed as well.
F Dagarin, M Petric, F Pohleven, M Sentjurc


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


Water-borne wood preservatives against marine borers. Results from NWPC marine trials started in 1972 and 1976
1990 - IRG/WP 4162
The paper presents the results from NWPC (Nordic Wood Preservation Council) marine trials started in 1972 and 1976. The trials are carried out according to the NWPC Standard No. 1.4.2.2./73 "Marine test - a test against marine wood boring organisms in sea water". The test site is Kristineberg Marine Biology Station on the west coast of Sweden. The wood blocks used in the trials were made from sapwood of European redwood (Pinus sylvestris L.). European beech (Fagus sylvatica L.), European birch (Betula spp.) and Norway spruce (Picea abies (L.) Karst) were also used to a minor extent. In all, 19 water-borne wood preservatives were tested. The preservatives consisting of copper-chrome, copper-chrome-arsenic, copperchrome-boron, copper-chrome-phosphorus and tributyltin oxide gave best performance. The ammoniacal copper preservatives failed to protect the wood against marine borers.
Ö Bergman, C Lundberg


Ten year field test with a copper-borate ground line treatment for poles
1993 - IRG/WP 93-30017
A wood preservative paste consisting of borax and copper naphthenate has been tested to determine its efficiency in protecting wood from decay fungi and insects. The paste was applied to polyethylene-backed wraps that were fastened to the below-ground portions of unseasoned southern pine pole stubs. After 4 years of exposure in Mississippi, the untreated control stubs were completely deteriorated. The below-grade portions of the treated stubs remained sound after nearly 6 years of exposure due to movement of copper and diffusion of the borate throughout the cross section. Borate and copper also moved vertically in the stubs and was present in sufficient amounts to protect sections of the stubs as high as 3 feet above grade. After 9 years of exposure, the below-grade portions of the treated stubs had limited areas of decay and no termite damage; the majority of the cross section remained sound. Wood analysis indicated that concentrations of borate in the sound areas were about 1/10 the estimated toxic threshold. A visual examination and push test indicated that the treated stubs continued to be protected at groundline after 10 years of exposure. It is hypothesized that the continued protection of the below-grade portions of the stubs against both decay fungi and subterranean termites is the result of copper-borate complexes that have formed in the wood.
T L Amburgey, M H Freeman


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


Comparative performance of several ammoniacal copper preservative systems
1997 - IRG/WP 97-30151
The efficacy of several ammoniacal copper-based wood preservative systems was evaluated in this study. The selection of potential co-biocides was based on the results of an agar plate test. Following this, the most promising systems were evaluated in a standard field stake test. Good correlation was found between the agar plate and field stake test results. Of the preservative systems tested, copper/tribromophenol, copper/naphthenic acid, copper/DDAC, and copper/propiconizole were found to be superior against copper tolerant fungi in comparison to the other systems tested after three years of field ground-contact exposure. The performance of copper/benzoic acid was mediocre. Copper/citric acid was ineffective against copper-tolerant fungi, with its performance being no better than copper alone.
D D Nicholas, T Schultz


Evaluating the natural durability of native and tropical wood species against Reticulitermes flavip
2004 - IRG/WP 04-10539
Environmental pressures to eliminate arsenate from wood preservatives has resulted in voluntary removal of CCA for residential applications in the United States. A new generation of copper organic preservatives has been formulated to replace CCA for decking and in-ground applications but there is no guarantee that these preservatives represent a permanent solution to all related problems. Therefore, it is still necessary to evaluate alternative treatments, as well as naturally durable wood species, in order to be prepared for future changes in the field. In this study, six hardwoods and six softwoods have been evaluated for their ability to resist termite damage by Reticulitermes flavipes in a 4-week laboratory no-choice test. In addition, moderately resistant Douglas-fir and southern pine wood blocks were evaluated after treatment with copper borate, copper naphthanate, and N,N-naphthaloylhydroxylamine (NHA). Erisma, juniper, ipe and white-cedar were shown to be highly resistant. NHA protected Douglas-fir and southern pine as effectively as copper borate or copper naphthanate. These results suggest that some naturally durable wood species, both tropical and native, can inhibit R. flavipes as effectively as preservative treatment.
R A Arango, F Green III, K Hintz, R B Miller


A comparison of the leaching resistance of diammine-copper complexes and copper carbonate precipitated in wood
1997 - IRG/WP 97-30158
Previous studies have shown that during treatment of wood with ammoniacal copper solutions, both simple copper precipitates and diammine-copper complexes are formed. The objective of the present study is to determine the relative importance of both forms of copper, on such aspects as preservative leachability and biological performance. In the current experiment, the leachability of copper carbonate precipitated in wood is compared with that of diammine-copper complexes. The results confirmed that both forms of copper resisted leaching by distilled water. However, when exposed to the more aggressive leaching conditions using the sodium citrate buffered solution, the diammine-copper complexes were significantly more ressistant to removal from the wood. Further studies are planned to examine the diammine-copper complexes present in the wood as well as the efficacy of these complexes against wood decay fungi.
Xiao Jiang, J N R Ruddick


A marine borer test with water-borne preservatives
1980 - IRG/WP 452
The use of preservative treated timber in sea-water where marine borers are active is of great economic importance, since untreated wood immediately will be damaged. Vacuum/pressure treated timber has been tested in several marine exposure trials on the Swedish west coast since the 1930s (Hager 1941, Hultman 1949, Sandstrom 1951, Nylinder-Norman et al. 1974). Since new interesting materials or preservative formulations are manufactured all the time, it is important to investigate their effect against the borers before they can be recommended and used in marine wood constructions. A Nordic standard method for testing wood preservatives in the sea was therefore worked out at the beginning of the 1970s (NWPC Standard No. 1.4.2.2./73). In principle following this standard an extensive test was started in 1972 to evaluate the effectiveness of various preservatives against wood borers. The test was located at the Kristineberg Marine Biology Station on the Swedish west coast. Results after the first 2.5 years (three growth seasons) were reported in 1975 (Norman and Henningsson). The present paper deals with the results after an exposure period of 6.5 years (seven growth seasons).
B Henningsson, E Norman


Remedial ground-line treatment of CCA poles in service. Results of chemical and microbiological analyses 6 months after treatment
1986 - IRG/WP 3388
CCA-treated poles in service with incipient internal soft rot were remedially treated by inserting borate rods, brushing with a boron/glycol solution and injecting boric acid paste, copper/creosote paste or a commercial product (DFCK paste). The spread of active chemicals in the treated zone as well as the change in microflora have been studied with time. After six months chemicals had spread to most parts of the pole in the ground-line zone and the microflora had been changed - in some cases drastically. The test is still in progress. Chemical and microbiological analyses after 12, 28 and 60 months will be published at a later date.
B Henningsson, H Friis-Hansen, A Käärik, M-L Edlund


Field performance of novel antisapstain formulations
1997 - IRG/WP 97-30125
The effectiveness as antisapstain formulations of combinations of oxine copper (Cu-8), carbendazim, hexaconazole, cyproconazole, flusilazole, didecyldimethyl ammonium chloride (DDAC), an alkanolamine borate (SB), benzalkonium chloride (BAC), 2-n-octylisothiazolin -3-one (isothiazoline) and p-chlorophenyl-3-iodopropagilformal (CPIPF) was determined for freshly sawn, block-stacked radiata pine in three 18-week field trials: 1. Established in summer 1992 evaluating combinations of hexaconazole, carbendazim and DDAC. 2. Established in autumn/winter 1994 evaluating combinations of hexaconazole, carbendazim, DDAC, BAC and SB. 3. Established in autumn/winter 1995 evaluating combinations of triazoles, DDAC, Cu-8, carbendazim, CPIPF, isothiazoline and SB. Reference standards included: Cu-8; Cu-8 + carbendazim; IPBC + DDAC and TCMTB. In all tests, formulations containing carbendazim + hexaconazole + DDAC gave better protection for 12 and 18 weeks than most other experimental formulations and were equal to or better than commercial standards.
D R Eden, R N Wakeling, C M Chittenden, J G Van der Waals


Tests with ammoniacal copper and alkyl ammonium compounds as wood preservatives
1984 - IRG/WP 3299
Formulations based on copper and alkyl ammonium compounds in ammonia solution have been tested in a fungus cellar on Pinus radiata and Fagus sylvatica. This type of products gives promising results as wood preservatives, especially on hardwood and are safe to destroy by e.g. combustion. The best results were achieved with a dialkyl ammonium compound, Cu/octyldecyl dimethyl ammonium chloride (NH3). The optimal weight ratio of Cu/AAC is for Pinus radiata = 0.2-0.4 and Fagus sylvatica = 1.0 based on cost-effectiveness. Fixation and leaching of coppertetrammine are discussed in detail. The leaching of active components from the Cu/AAC/NH3-systems is very low.
C-E Sundman


Performance of Paraserianthus falcataria treated with ACZA, ACQ, CC or CCA and exposed in Krishnapatnam harbour, India
2005 - IRG/WP 05-30382
Paraserianthus falcataria (=Albizia falcataria) treated to two retentions with ammoniacal copper zinc arsenate (ACZA), ammoniacal copper quaternary (ACQ), ammoniacal copper citrate (CC) and chromated copper arsenate (CCA) was assessed over 34 months in a tropical marine waters at Krishnapatnam harbour on the east coast of India. ACZA treatment showed comparatively better resistance than CCA, ACQ and CC, while CC provided the least resistance to marine borer attack. Eight species of borers i.e. Martesia striata, M. nairi, Teredo furcifera,T. parksi, Lyrodus pedicellatus, Nausitora hedleyi, Bankia campanellata and B. rochi were recorded on test panels. Of these, M. striata, L. pedicellatus, T. furcifera and B. campanellata were the dominant species, while other species settled sporadically. The results suggest that copper based preservatives are less likely to perform well under extreme tropical exposures without arsenic.
B Tarakanadha, K S Rao, J J Morrell


Diffusion modeling of inorganic wood preservative leaching in service
2005 - IRG/WP 05-50224-5
To evaluate the potential environmental and health implications of leaching of inorganic wood preservatives in service under different conditions, there is a need for a predictive model that provides estimates of the rate and extent of leaching over a wide range of product dimensions and exposure conditions. In this paper, we show that the leaching behavior of inorganic preservative components from wood in continuous water contact can be characterized by three easily measured parameters: total leachable component (Le) based on intensive leaching of fine ground material; amount of dissolved or dissociated component (Di) in water saturated wood; preservative component diffusion coefficients (Dt,l) in the transverse and longitudinal directions. Use of the applicable D and Di or Le in a diffusion model allows the prediction of total amount leached and emission rate at different times of exposure. Both D and Di increase somewhat with increasing ambient temperature. Laboratory determined parameters for alkaline copper quaternary (ACQ), copper azole (CA), chromated copper arsenate (CCA) and borate (DOT) wood preservatives are used to predict leaching rates from larger lumber samples. Preliminary comparisons of predicted leaching with measured leaching of larger samples in laboratory and natural rain exposure indicate that the approach is surprisingly effective at predicting leaching performance but some model refinements are needed for some components such as copper in CCA to account for the slow dissolving of a component of the preservative available for leaching.
L Waldron, P A Cooper, Y T Ung


Diffusion and interaction of components of water-borne preservatives in the wood cell wall
1988 - IRG/WP 3474
This study investigates the rates of diffusion and ultimate distributions of copper and arsenate components of wood preservatives in wood cell walls following vacuum treatment. Adsorption studies of copper on red pine (Pinus resinosa) and trembling aspen (Populus tremuloides) wood confirm the importance of cation exchange reactions on the ultimate distribution of copper in the wood substance and its strong dependence on pH of the treating solution. Formulations containing both copper and zinc preferentially adsorb or exchange copper relative to zinc. Under high pH conditions, the arsenate anion is significantly adsorbed into the cell wall. The combined adsorption and fixation of low pH CCA solutions is much slower than adsorption of high pH ACA and CZA formulations, but the reaction with wood is more complete. Diffusion coefficients were estimated for the movement of copper and arsenate components of ACA in cell wall material of both aspen and pine sapwood using a simple membrane model for non-steady state diffusion. The longer diffusion paths inherent in the diffuse porous hardwood (aspen) resulted in much slower equalization of the solute in the cell wall matrix than in red pine. However, in both species, equalization was achieved in a relative short time compared to accepted fixation times for conventional waterborne wood preservatives.
P A Cooper


Stake test with ammoniacal copper in combination with different agents started in 1962
1997 - IRG/WP 97-30130
In 1962 a stake test was started with ammoniacal copper in combination with chromium, arsenic, pentachlorophenol, boron, salicylic acid, benzoic acid, sorbic acid, pyridine and tannin. Different concentrations of the copper component were used as well as the added agents. For each concentration and test site, ten stakes of Pinus sylvestris L. sapwood were treated. The stakes were set out at two test fields in Sweden, Simlångsdalen and Bogesund and also in a greenhouse. Today all stakes except five at Bogesund have been rejected. The prevailing type of decay in Bogesund is soft rot and in Simlångsdalen brown rot and soft rot. Ammoniacal copper alone at a copper retention of 1.9 kg/m3 gave an average service life of 23 years in Bogesund and 14 years in Simlångsdalen. When the copper retention was doubled to 3.8 kg/m3 the service lives were prolonged by 2-3 years in Bogesund and 8-9 years in Simlångsdalen. Most of the agents added to copper prolonged the service lives substantially in Simlångsdalen but only marginally, or not at all in Bogesund. The added agents which gave the longest service lives at both test fields were chromium plus arsenic and pentachlorophenol.
B Häger, Ö Bergman


Effect of test site location on in-ground preservative performance after 6 years
2001 - IRG/WP 01-20231
Pinus radiata test stakes were treated with 4.1 kg/m3 of CCA and Fagus sylvatica with 6.1 kg/m3 of CCA. Both wood species were also treated with a copper plus triazole preservative (3 kg/m3 of copper) and chlorothalonil plus chlorpyriphos in oil (4.8 kg/m3 chlorothalonil). Furthermore, P. radiata was treated with ammoniacal copper plus a quaternary ammonium compound (2.6 kg/m3 copper) and a 60/40 mixture of high temperature creosote plus oil (61 kg/m3 creosote). Treated and untreated stakes were exposed in the ground at 13 sites in New Zealand and Australia for approximately 6 years. Preservative performance was significantly affected by site and there was a site-preservative interaction effect where decay hazard at a given site was dependent on preservative treatment. For pine, chlorothalonil plus chlorpyriphos, copper-azole and ACQ gave at least equivalent performance to the reference standards creosote and CCA, after approximately 6 years, at the majority of test sites. For beech, chlorothalonil plus chloropyriphos and copper-azole both gave superior protection to CCA, at the majority of test sites. In general, the results suggest that it is possible to select 3 - 4 sites that collectively pose a diverse decay hazard, representative of the majority of situations encountered by wood in service.
R N Wakeling


Influence of water-borne preservatives on water repellency and the impact of addition of water repellent additives
1992 - IRG/WP 92-3704
The primary goal of a desirable wood preservative system is to effectively control decay fungi and other biodeteriogens in service. The water repellent nature of a given system may play an important role in the protection of wood. In this study, the water repellency of several water-borne preservative systems has been evaluated by measurements of tangential swelling during immersion. The systems include cuprammonium formulations, such as ammoniacal copper carbonate (AC) and ammoniacal copper zinc arsenate (ACZA), ammoniacal copper quat systems (ACQ) and chromated copper arsenate (CCA). The influence of addition of water repellent emulsions into the above systems has also been examined.
L Jin, D M Roberts, A F Preston


Amine copper reaction with wood components: acidity versus copper adsorption
1997 - IRG/WP 97-30161
The bonding sites for copper in wood from CCA, as well as ammoniacal/amine based systems, has long been a topic of investigation. Both phenolic and carboxylic functional groups have been discussed as potential bonding sites for copper. However, no consensus on the adsorption mechanism has been realized. Thus, the selective adsorption of copper in southern yellow pine from ethanolamine-copper solutions and its correlation to wood acidity is currently being investigated. The wood acidity has been determined by acid/base titration, and is due to more than one type of acidic group. The acid(s) can be removed by thermal treatment or extraction techniques, and, interestingly, the selective adsorption of copper was observed to track the presence of particular acid functionalities. The preferential adsorption of copper and the mechanisms behind such will be discussed.
S M Thomason, E A Pasek


Upgrading the fungal resistance of OSB
1999 - IRG/WP 99-40138
There is a perception that oriented strand board (OSB) is less resistant to fungl than plywood under conditions of moderate exposure to moisture. Douglas fir-faced plywood (DFP) has been suggested as a benchmark for acceptable durability under such conditions. This project was initiated to determine the minimum level of low-toxicity chemical treatment needed to upgrade the fungal resistance of OSB, made from aspen, to equal that of DFP. Against a brown-rot fungus in a soil-block test, 0.2% zinc borate (ZB), added during manufacture, and subsequent spray treatment with 10 µg/cm2 oxine copper provided the required performance. Against a white-rot fungus 0.2% ZB alone was sufficient and between 0.1 and 0.2% may have been adequate. For resistance to mould in a humidity chamber, spray treatment of OSB with 10 µg/cm2 oxine copper provided equivalent performance to DFP. The recommended combination of treatments for moderate moisture exposure is 0.2% zinc borate and 10 µg/cm2 oxine copper.
P I Morris, J E Clark, D Minchin, R Wellwood


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