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Interactions between water-borne preservatives and emulsion additives that influence the water repellency of wood
1991 - IRG/WP 2374
Incorporation of non-polar additives into water-borne treatments through of emulsion technology can greatly improve the physical characteristics of wood in service. Of specific interest with these emulsions is their effectiveness in reducing the rate of wood swelling. We have observed that the presence or absence of preservatives can often significantly influence the resultant effectiveness of the water repellents when measured in an immersion swelling test. This paper describes some preliminary results of experiments comparing the relative effectiveness of a water repellent additive when used in combination with CCA-C as well as the effect of preservative concentration on water repellency.
A R Zahora

The effect of temperature on the rate of fixation of an alkyl ammonium compound (AAC) wood preservative
1984 - IRG/WP 3293
The rate of fixation of an alkyl ammonium compound wood preservative was measured by soaking samples of wood wool in various preparations of the preservative for arbitrary times followed by immediate leaching in water. The wood wool was then analysed for residual preservative. The results indicated that fixation was very rapid and increased at higher temperatures.
P Vinden

The influence of previous anti-blue-stain preservative treatments on the fixation of CC in spruce
1997 - IRG/WP 97-30134
Freshly cut and kiln dried spruce boards were treated with 4 different anti-blue stain preservatives (ABP). After a period of 10 days allowing the samples to dry and fixate, the samples were treated with CC (chromium, copper formulation) using a vacuum pressure cycle. After impregnation the wood was steam fixed. A submersion leaching test showed differences in the leachable quantity of copper and chromium. When related to the retention of both salts after impregnation, no differences could be found between samples previously treated with anti-blue-stain preservatives and untreated samples. However, the retention of CC diminished significantly by application of quaternary ammonium compounds.
M Van der Zee, W J Homan

Interaction mechanisms of F/Cr/As/B type preservative and wood
1981 - IRG/WP 3183
The paper reports results of investigations on the fixation of the components of a F/Cr/As/B preservative in wood and its lignin and cellulosic components.
N Ermush, I Andersone

Remedial treatment of joinery. Comparison of distribution of organic solvent preservative and ammonium bifluoride
1978 - IRG/WP 3115
It is some years since it was recognised in the United Kingdom that there was a problem of premature decay in untreated external joinery. Consequently, recommendations for preservative treatment were made by the Building Research Establishment, Princes Risborough Laboratory. In addition, the National House-Building Council has also included the preservative treatment of external joinery in its requirements. Thus, a large proportion of external joinery manufactured in the U.K. is now preservative treated, mainly in double vacuum impregnation plants. There still remain, however, relatively new buildings where preservative treatment has not been specified and where fungal decay is a problem. Decay occurs most frequently in the lower horizontal members such as cills, and the lower rails of opening lights. The damage is often most severe at the joints, where entry of water is facilitated by exposure of end grain. In some circumstances such as in Local Authority buildings where some of the more exposed joinery has already decayed, it has been considered economic to treat the remaining sound or near-sound joinery in situ in order to prevent future attack and to arrest any slight decay that may already be present. This treatment is normally applied by injecting organic solvent preservative under pressure in the region of the joints and where considered necessary along the lower horizontal member. As an alternative method of treatment, we have investigated the possible use of ammonium bifluoride, since diffusion of gaseous hydrogen fluoride may be expected to penetrate more extensively into wet timber than organic solvent preservative. The work described below was carried out in order to assess the comparative penetration of fluoride and organic solvent preservative in redwood (Pinus sylvestris).
J M Taylor

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

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

Biological test, AAS and EPR study of copper monoethanolamine complex with quaternary ammonium compounds as a wood preservative
2003 - IRG/WP 03-30321
Experiments were carried out on the wood preservative with a strong fungicidal activity based on Cu(II) carbonate, 2-aminoethanol (monoethanolamine) and quaternary ammonium compound (QAC). The object of the performed investigations was sapwood of Scots pine (Pinus sylvestris L.) treated with Cu-EA-QAC formulation. Mycological investigations were carried out according to EN 113 and EN 84 standards. The retention of the copper ions in the wood grows nonlinearly with concentration (in %) of the impregnating solution from 0,25 kg/m3 at 0.03% to 1,55 kg/m3 at 0.21% (i.e. nearly 6 times) whereas the copper leachability decreases 2,5 times from 15% to 6% in the same range. These results indicate good fixation of the copper to the wood and high leaching resistance. EPR results and computer simulations of the observed EPR spectra shows that in Cu-EA aqueous solution the Cu(EA)2(H2O)2 complexes exist and the main coordination plane is not destroyed in impregnating solution and in the wood. In Cu-EA-QAC-BA solution the Cu(EA)2(QAC)2 complexes appear whereas EPR spectra of the treated wood indicate coexistence of a few types of Cu-complexes. We have identified strongly fixed Cu(EA)2O2 and Cu(EA)2O complexes with oxygens atoms from wood functional groups.
B Mazela, I Polus, S K Hoffmann, J Goslar

The influence of timber species and preservative treatment on spore germination of some wood-destroying Basidiomycetes
1988 - IRG/WP 2300
Basidiospores from six wood decay fungi exhibited varying germination rates on untreated softwood and hardwood blocks. Germination inhibition of all test fungi was recorded on pine sapwood. No preference for a certain timber species by a particular fungus was evident. Whereas almost complete inhibition of germination occurred on wood treated with a quarternary-ammonium based wood preservative, most fungi germinated successfully on wood treated with a boron based preservative. Further work is necessary to determine whether a reliable preservative screening using spore germination tests as criteria can be developed.
B M Hegarty, G Buchwald

Polymeric Betaine as a Wood Preservative
2008 - IRG/WP 08-30487
Didecyl polyoxyethyl ammonium borate (DPAB), also known as Polymeric Betaine, was developed as a co-biocide for chromium-free copper based wood preservatives in Europe in the 1980’s. This paper summarizes the properties of DPAB as a wood preservative. Unique properties related to the betaine nature of DPAB are discussed in terms of the structure-property relationship. Physical properties of DPAB treated wood and properties of DPAB formulations are discussed. Unlike many preservative systems which have negative impact on strength and other physical properties of wood composites, it was discovered that DPAB based formulations were especially suitable for treating wood furnish before composite manufacturing. Typical laboratory and field performance data of DPAB formulations are presented.
H Härtner, S Schmitt, Futong Cui, H M Barnes

Micronized Copper Preservative Systems: Observations on the Release of Cupric ion (Cu2+) from Treated Wood and Performance against Wood Decay Fungi
2009 - IRG/WP 09-30519
In an attempt to address the mechanism of action of micronized copper preservatives, a 20-week continuous water leaching study was conducted. The leaching results indicated that, once impregnated in wood, micronized copper preservatives continuously release cupric ion, and the levels of cupric ion released from micronized copper treated wood are higher than those released from CCA treated wood, and similar to those from ACQ-D treated wood with the exception of the first few leaching cycles. A 30-month soil bed fungal cellar test was also conducted, and the results revealed that micronized copper quat performed at least as well as ACQ-D against soft rot, confirming the presence of mobile cupric ion in the S2 layer of wood cell wall. In addition, two field stake studies of micronized copper preservatives were also conducted, and the results indicate that micronized preservative systems provide excellent long-term protection against wood destroying fungi and insects, and perform at least as well as ACQ-D.
J Zhang, R Ziobro

Distribution and availability of preservative components in ACQ treated wood - effects of coatings and weathering
2010 - IRG/WP 10-30537
Copper and quaternary ammonium compound (quat) distributions across lumber (gradients) and availability, as measured by amount removed by intensive leaching of wood flour, were measured in ACQ treated southern pine lumber. Samples were evaluated just after treatment and stabilization, or after 3 years of laboratory storage, or after 3 years of natural weathering exposure. The objective was to investigate how the distributions of copper, quat and monoethanolamine (MEA) changed under different exposure conditions to try to explain the long terms effects of semi-transparent wood coatings to reduce leaching, even after partial failure of the coatings. In unweathered lumber, there was a slight copper gradient from the surface to the interior of the lumber and a steeper quat gradient. Analysis of specimens after 3 years of weathering exposure confirmed the effectiveness of the coatings to reduce copper and quat leaching and showed that quat leaching from uncoated samples was substantial. There was little effect of aging indoors on availability of ACQ components. However, the availability of copper was significantly reduced after 3 years of natural exposure, even after accounting for the copper that leached during weathering. It was observed that the MEA availability was greatly reduced, presumably by preferential leaching compared to copper and quat during weathering. This appears to have reduced the amount of soluble/available copper resulting in lower long term copper leaching, especially in coated samples that were protected from high copper losses by the effect of the coating. The reduced quat leaching from coated samples is attributed to the long term effectiveness of the coatings in the earlywood portions of the samples.
T Ung, M Nejad, P Cooper

Confocal laser scanning microscopy of a novel decay in preservative treated radiata pine in wet acidic soils
1997 - IRG/WP 97-10215
Light microscopy of radiata pine (Pinus radiata D. Don) field test stakes (20x20x500mm3) exposed in wet acidic (pH 3-4) soil for 12 - 24 months showed predominance of an unusual type of decay characte-rised by tunnelling attack of wood cell walls. After two years decay was moderate to severe in wood treated to ground contact CCA specifications and also equivalent retentions of creosote, and a number of new generation preservatives. Relative to other New Zealand temperate test sites and also an Australian tropical site, the New Zealand acidic soil test site was very aggressive. Correlative scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to elucidate the micromorphology of this attack. Tunnels of diameter 0.2-5 µm were present throughout all layers of the cell wall, and their orientation was not related to cellulose microfibril orientation. They also showed no preference for particular cell wall layers, indicating a lignin degrading capability. CLSM images showed that living, connecting fungal hyphae were present in the cell lumina and tunnels. This type of attack was predominant in wood that was highly saturated with water whereas wood that was less moist was predominantly attacked by classical white rot. Ongoing isolation and incubation studies in conjunction with further microscopy should enable identification of the fungal species involved.
R N Wakeling, Ying Xiao, A P Singh

Status of the research and development of a new preservative system (EFPL) for pressure treatment of spruce in Canada
1975 - IRG/WP 348
Our work has been to develop a system which would have the stability of the ACA system and the formulation flexibility of the CCA system enabling properties such as fixation of arsenic, water repellency, appearance and cost to be controlled. Our permeability studies of spruce using a method previously developed indicated that an ammoniacal solution of copper arsenate is an excellent candidate for the treatment of spruce. Studies of the permeability of spruce sapwood microsections to CCA preservative and to an ammoniacal solution of copper arsenate proved that the ammoniacal system penetrates 1.7 to 1.8 times faster than the CCA system, in the radial direction. The permeability in the tangential direction was on the average 3.8 times better. These results were confirmed by pressure treatments of spruce lumber and spruce roundwood with both preservatives.
J Rak, M R Clarke

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

Registration and approval of wood preservatives in Australia and New Zealand
2001 - IRG/WP 01-50166-06
Wood preservatives are treated as agricultural chemicals in Australia and, at the time of writing, as pesticides in New Zealand. Antisapstain products are currently considered to be agricultural chemicals in New Zealand while wood preservatives in the future will be considered as hazardous substances under the Hazardous Substances and New Organisms Act when this Act is fully implemented. They are regulated and approved for use by Government Departments under Ministers with responsibilities for agriculture and forestry and the environment: in Australia this is the Department of Agriculture Fisheries and Forestry; in New Zealand it is the Ministry of Agriculture and Forestry and, in the future, the Ministry for the Environment. Specific authorities within these Government instrumentalities control the registration and approvals procedures - the National Registration Authority (NRA) in Australia and, currently, the Pesticides Board in New Zealand. The latter situation is in a transition phase, with the Environment Risk Management Authority (ERMA) New Zealand expected to take over from the Pesticides Board by mid-2001. The NRA and the Pesticides Board require data packages that must include details of the preservative's application, chemistry, manufacture, toxicology, environmental credentials, and efficacy. The NRA administers the Agricultural and Veterinary Chemicals Code, which provides the Authority with the power to evaluate, register for use, and regulate the point of sale of a preservative. The evaluation procedure may involve Environment Australia in focusing on exposure and environmental toxicity data, the Department of Health and Aged Care in assessing toxicity to humans and the National Occupational Health and Safety Commission considering user safety aspects. Efficacy data can be obtained through testing to the Australasian Wood Preservation Committee (AWPC) Protocols. AWPC members may also act as experts in the assessment process and may also be involved in the development of national Standards. Thus, there is a ready conduit from registration and approval of a potential preservative to its incorporation for end use into day-to-day working standards.
H Greaves

Testing of wood preservatives against marine borers (Part 1). Method of testing wood preservatives against marine borers (Part 2)
1971 - IRG/WP 37
P C Trussell, C C Walden

Improved techniques designed for evaluation of fungicides in soil for control of dry rot fungus Serpula lacrymans
1985 - IRG/WP 2238
Improved techniques provide a laboratory method for the evaluation of chemicals in soil for control of dry rot fungus Serpula lacrymans. Results with their application to three chemicals were reported. These techniques are useful to eliminate chemicals lacking the necessary toxicity and weatherbility for dry rot control when the chemicals have been applied to the soil.
M Takahashi, K Nishimoto

Field performance of wood preservative systems in secondary timber species
1997 - IRG/WP 97-30152
The objective of this ongoing study is to evaluate the performance of new, potential, and standard wood preservative systems in secondary North American timber species. Eleven preservative systems were evaluated in this study - ACQ Type B, Copper Citrate 2: l, CDDC, chlorothalonil/chlorpyrifos, copper-8-quinolinolate, tebuconazole/chlorpyrifos, RH287, propiconazole/chlorpyrifos, copper naphthenate, CCA. and creosote. Field evaluations are being performed with ground contact field stakes and termite-specific testing in Hawaii, along with laboratory soil bed tests. The major wood species used with all the systems and evaluation methodologies are loblolly pine, northern red oak, tulip poplar, and cottonwood. More limited evaluations (field stakes only) are being conducted with eastern hemlock, red maple, and sweetgum. Information is presented from laboratory soil bed, field termite, and field stake evaluations. There is good correspondence between soil bed and field stake results. The more highly developed preservative systems and those in an AWPA P9 Type A oil carrier tend to perform better, and there can be a strong affect on performance from the wood species.
P E Laks, K W Gutting, R C De Groot

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

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

Insect resistance of preservative treated tropical plywood against Lyctus
1990 - IRG/WP 1453
Seven plywood types composed of tropical wood species, vulnerable to Lyctus, were treated with various commercial water-borne and oil-borne preservatives. A wide range of preservative retentions was obtained by treating boards with dip treatment, steeping, double-vacuum and vacuum-pressure impregnations. Selected samples were subsequently tested for their insect resistance against Lyctus africanus during 6 to 8 months according to European Standard EN 20. All control samples were attacked, except one Obeche plywood exhibiting only 50% attack. Water-borne preservative solutions containing arsenic, boron or fluoride could not prevent attack at common retention levels for interior use e.g. lower than 5 kg/m³. Quaternary ammonium compounds showed no insecticidal efficiency, up to 3 kg/m³. TCMTB at 1.5-1.7 kg/m³ proved to be able to reduce slightly the susceptibility for insect attack. Organic insecticides gave the best results, with nearly no attack for plywood treated with lindane or cypermethrin. In spite of a preservative uptake of 25 to 30 kg/m³, endosulfan only could reduce attack by 50%. Protection by permethrin at 0.1% a.i. required a retention of 28 kg/m³. Besides the fact that variability in wood species and composition of the plywood are leading to different retention levels, variation in penetration and distribution of a.i., and as a consequence to a different insect resistance of the impregnated boards, some poor results were directly related to inadequate insecticidal activity and/or concentration of a.i. in some commercial formulations for Lyctus control.
J Van Acker, M Stevens, M Pallaske

Performance of preservative-treated hardwoods with particular reference to soft rot. Report of condition of specimens installed in Victoria, Australia
1980 - IRG/WP 3155
J Beesley, R McCarthy

Protocol for evaluation and approving new wood preservative
1985 - IRG/WP 2159
M E Hedley, J A Butcher

A novel method for delivering fluids into bolted wooden components.
2004 - IRG/WP 04-40280
The paper describes the development of a washer that enables fluids such as wood preservatives and adhesive resins to be delivered to bolted wooden components in-situ. The system was developed to meet the criteria of low cost and the ability to tolerate inaccurate drilling of holes in the wooden members.
G S Sawyer, B Tole

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