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Borate thermal treatments
1992 - IRG/WP 92-3715
Green, partially seasoned (air-dried, steam conditioned), or kiln-dried southern pine timbers were treated thermally using 15% disodiumoctaborate tetrahydrate solution. After treatment, sections were stored under non-drying conditions to allow for diffusion. Results showed that effective treatment meeting the AWPA minimum retention (0.17 B203 pcf [2.72 kg/m³] in the outer inch) and penetration (2.5-in [64-mm] or 85% of the sapwood) could be obtained only with certain combinations of seasoning, treatment, and diffusion storage. The best results in terms of both retention and penetration were obtained with material steamed and stored prior to treatment using a 10-min hot bath time. Kiln-dried timbers could not be treated effectively. The results suggest that non-conforming treatment of green or partially seasoned timbers will require higher solution concentrations, higher hot bath temperatures, and/or longer diffusion periods to meet required standards. Results also indicated that treatment of smaller stock in dimension sizes (up to 2-in [50-mm]) should be feasible.
H M Barnes, R W Landers, L H Williams

The long-term performance of boron treated joinery in service - A case study
2000 - IRG/WP 00-20208
Joinery treated with borates 23 years ago and in service in residential flats was surveyed and analysed for boron content. The levels of boron still present were sufficient to prevent decay. None of the windows surveyed showed any decay despite the fact that moisture and sapwood contents were conducive to decay.
D J Dickinson, R J Murphy

Assessment of losses of wood preservatives from treated wood by leaching into the environment
1993 - IRG/WP 93-50001-13
Wood preservative chemicals may be lost from treated timber by leaching into water or soil. The degree to which this might occur and its effect on the environment is difficult to assess quantitatively due to the absence of appropriate test methods. This paper describes work to assess test methodology capable of allowing the rates of loss of wood preservative from treated timber to be quantified. The possibility of adapting simple laboratory equipment to monitor preservative losses from treated wood has been investigated. Losses due to leaching from selected faces of treated wood blocks when immersed in water have been monitored, using disodium octaborate as a model water-soluble preservative. The investigation has demonstrated the importance of distinguishing between transverse, radial and tangential surfaces when considering potential losses and the subsequent likely environmental impact of treated timber in service.
R J Orsler, G E Holland

Discussion of diiodomethyl p-tolyl sulfone (Amical® 48) as a fungicide for wood preservatio
1987 - IRG/WP 3425
The effectiveness of diiodomethyl-p-tolyl sulfone (Amical® 48) as a fungicide for preservation of wood is supported by a discussion of results from the literature and current research programs.
J M Stamm, K J Littel, F M H Casati, M B Friedman

Biological performance of gypsum products containing borates
2000 - IRG/WP 00-30237
At suitable retentions borates have biostatic properties enabling them to be used for biodeterioration control in wood. They provide protection against decay fungi, mould, and termites, which are known to also attack gypsum products. Currently, many gypsum products contain added borates, which are used to improve physical and processing characteristics. Work examining the effect of borates at controlling biological attack in gypsum products is presented in this paper. Gypsum or gypsum board with different borate loadings was tested for its performance against dry rot, mould, and subterranean termites in order to see if current commercial levels of borates used in gypsum products would also render them resistant to these common types of biodeterioration. It was confirmed that the presence of borates significantly decreases the amount of biological attack found in gypsum products. From the results obtained it can be concluded that the addition of borates to gypsum products provides more than simple mechanical and processing improvements. For complete biodeterioration control however, especially against mould, higher retentions should be considered. This knowledge could have great significance in the near future, with moves to require termite resistant construction materials (including gypsum board) in some areas and the rising concern of illnesses associated with 'sick building syndrome' caused by in-house mould growth.
J L Fogel, J D Lloyd

Volatile borates in the treatment of wood and wood based panel products against subterranean termites
1995 - IRG/WP 95-30094
Blocks of pine solid wood, oriented strand board and plywood were treated with trimethyl borate by vapour treatment. It was meant to obtain either a full impregnation of the specimens or a shell treatment of the outer three millimetres. The efficacy of the treatments against subterranean termites (Reticulitermes lucifugus) was evaluated using an European Standard method.
L Nunes, D J Dickinson, R J Murphy

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

Austrian field test method for anti-sapstain chemicals
1994 - IRG/WP 94-20020
Although Austria is a small country, the annual consumption of anti-sapstain products ranks to approximately 500 tons annually. In 1994, only three products will be approved by the Austrian Wood Preservation Committee (AWPEC). There is demand for a field test method, which demonstrates the efficacy of an anti-sapstain product and consequently implies the acceptance and approval of product by the AWPEC. Present field test was carried out in 1992 and 1993. The results were evaluated after six months storage of test stacks. A TCMTB based product was used as a reference. The results show that the AFPRL method proves very suitable for the simulation of practical situation in Austrian treatment plants, where pine and/or spruce are treated periodically and where different methods of stack storage are applied.
R Gründlinger, M Brandstätter, H Melzer, O Janotta

Borates and their biological applications
1998 - IRG/WP 98-30178
This paper reviews some of the many biological applications of borates. Boron is a ubiquitous element found widely distributed in the environment and is a normal component of a healthy diet. Elemental boron does not exist in nature, but is always found combined with oxygen in compounds called borates. Boron is an essential micronutrient for plants, and there is evidence to suggest that boron is of nutritional importance, if not essential, for humans. Borates possess biostatic activity which enabled their use in medicine and has allowed their continued development as preservatives. The essentiality of boron in plants has led to extensive biological use in agriculture. The biostatic properties at high doses have enabled their use in biodeterioration control, against insects, fungi, algae and bacteria. Some use is currently being made of borates for insect control in the home. The application of borates to crops, to alleviate boron deficiency, has resulted in recognized increases in quality and yield. Consideration of the relative safety and effectiveness of borates as biocides, is expected to lead to an increase in the use of these products in the future.
J D Lloyd

Potentialities of protein borates as low-toxic, long-term wood preservatives - Preliminary trials
1999 - IRG/WP 99-30212
Boron compounds are efficient wood preservatives, as well as safe for the mammals and environmentally acceptable. Their natural solubility allows them to treat almost any wood species, but is also the cause of their high depletion from treated timber in outside exposure. In order to reduce this leachability, potentialities of proteinic polymer networks retaining boron within the wood have been investigated. Several mixtures of boric acid and proteins (including ovalbumin, collagen, casein, soya flour) have been used to treat pine sapwood miniblocks. The insoluble networks were obtained by protein gelation or coagulation, induced by a physical and/or a chemical factor. These systems appeared to retard boron leaching, the decrease of the leachability rate depending on the protein and the denaturing agent involved in the network creation. The best results have generally been observed for the irreversible heat-induced protein gels. These associations are also able to conserve some boron mobility and activity. Accelerated biological tests of leached wood samples showed good durability performances against Basidiomycetes. The use of protein borates seems to be an interesting basis for low-toxic wood preservatives. Furthermore, in some cases, proteins could add their anti-nutritional factors to boron efficacy to enhance wood protection.
M-F Thévenon, A Pizzi, J P Haluk

Diffusion of bifluorides and borates from preservative rods in laminated beams
1991 - IRG/WP 3644
Laminated beams from spruce, pine and larch were treated with two preservative rods, based on bifluorides and octaborate respectively. After 3 and 6 months placed in different climates (65% r.h., 100% r.h., water) the diffusion of the active ingredient was measured. After the 6 months period, the diffusion of the bifluorides was, in all species, ca. 5 times larger than the diffusion from octaborate rods. The bifluorides were not hindered by the glue-lines. The diffusion of the borate was poor, mainly perpendicular to the grain and was hindered by the glue-line.
H Militz

The use of zirconium as an inert fixative for borates in preservation
2001 - IRG/WP 01-30256
Stand-alone borates have been used in internal protected situations as wood preservatives for about 60 years. They have not been deemed acceptable for external situations because of their leaching characteristics. Work carried out to reduce the leachability of borates has been reviewed briefly here, and a specific fixation agent based on zirconium has been tested in standard leaching and decay tests. It was found that the performance of zirconium could be optimized for fixation at specific drying temperatures and at higher formulation pH. Using sufficient quantities of ammoniacal zirconium carbonate and potassium zirconium carbonate such formulations are then able to pass both Standard European and American Wood-Preservers' Association methods designed for testing exterior wood preservatives. Formulations based on borate with a zirconium additive are probably suitable for use in exterior above ground and possibly ground contact situations. As only initial indicative tests have been carried out so far, further testing with a range of wood destroying organisms and field tests should be carried out to evaluate this system further.
J D Lloyd, J L Fogel, A Vizel

Effect of borate on uptake and efficacy of an anti-sapstain treatment
2005 - IRG/WP 05-30380
The potential for using borates to enhance uptake and efficacy of propiconazole-based anti-sapstain chemicals was assessed on ponderosa pine sapwood wafers. Borates had no consistent effect on either net solution absorption or propiconazole distribution in the wood. Even small amounts of borate, however, markedly improved the performance of propiconazole against fungal discoloration. These results are consistent with previous tests of borate addition to other fungicides and highlight the potential for using less expensive ingredients to boost the performance of more costly biocides.
Jianju Luo, Hua Chen, J J Morrell

Leaching of inorganic wood preservatives – Investigating the relationship between leachability, dissociation characteristics and long-term leaching potential
2003 - IRG/WP 03-50199
Estimation of the leaching properties of preservative components is greatly affected by the leaching test method applied since not all methods equally consider the physical components responsible for leaching. These include: wetting of the wood and penetration of water (affected by dimensions, amount of end grain, permeability, duration and nature of water exposure); solution of preservative components into available moisture (affected by component solubility, wood moisture content, temperature, etc.); diffusion of components out of wood (affected by product dimensions, permeability, direction of movement, moisture content, temperature, nature of the diffusing species, etc.); and re-drying of the wood between moisture exposures. Aggressive leaching of finely ground wood provides a measure of the ultimate amounts of preservative compounds available for leaching while analysis of the equilibrium dissociation or solubility of components in free water in the wood provides information on their effective concentration which drives the diffusion process. Combining this information with a simple diffusion test should allow the estimation of potential risk from leaching over a wide range of specified conditions. In this paper, the leaching of several inorganic wood preservatives is compared and related to dissociation of preservatives within the wood structure and diffusion out of wood.
L Waldron, Y T Ung, P A Cooper

Preliminary evaluation of borate baits and dusts for eastern subterranean termite control
1990 - IRG/WP 1433
Borates are of potential use in the development of baiting systems for subterranean termite control. In the 15-day laboratory assays reported here, the oral toxicity of disodium octaborate tetrahydrate to Reticulitermes flavipes (Kollar) was evaluated under choice and no-choice conditions. These assays suggest a range of 2500 to 5000 ppm to be applicable in developing baits, and that concentrations greater than 5000 ppm may deter feeding. Laboratory assays with borate dusts (disodium octaborate tetrahydrate, zinc borate, and a fine-grain zinc borate) are also reported. In a toxic variation of mark-release methodology, these materials are passed among the test group by grooming foragers exposed to the dust. In these assays, 10% of the test group was exposed to the borate dust, then released placed in contact with unexposed workers in a simulation of a field release. Zinc borate treatment elicited the greatest mortality (99-100%), although disodium octaborate tetrahydrate also elicited mortality significantly greater than that in the control groups. These results suggest that less soluble borates may be more efficient dust toxicants, and that capture and dust-treatment of a portion of the foraging termite population could elicit high mortality among termites contacting the treated individuals after their release back into the colony.
J K Grace, A Abdallay, J M Sisson

Eastern subterranean termite responses to three soil pesticides
1990 - IRG/WP 1432
In laboratory assays simulating field conditions, tunneling and mortality of Reticulitermes flavipes (Kollar) workers were evaluated in sand treated with aqueous solutions of formulated chlorpyrifos, isofenphos, and disodium octaborate tetrahydrate. Chlopyrifos and isofenphos were evaluated at concentrations of 500 and 1000 ppm (weight of active ingredient / weight of sand), and disodium octaborate tetrahydrate at 2500 and 5000 ppm. No tunneling was observed in sand treated with chlorpyrifos, and high termite mortality suggested vapor and/or high contact toxicity. Tunneling was initiated in isofenphos-treated sand, and termites subsequently died in the tunnels from contact toxicity. At both concentrations, termite mortality from isofenphos exposure was equivalent to that with chlorpyrifos, but the shorter tunnel length at the higher isofenphos concentration (1000 ppm) indicated a concentration-dependent rate of mortality. Greatest tunneling was observed in sand treated with disodium octaborate tetrahydrate. Low and variable mortality with this compound at 2500 ppm are attributable to its slow toxic action and, possibly, difficulty in obtaining an homogenous distribution. Tunneling was not inhibited at 5000 ppm, but mortality was comparable to that observed with 1000 ppm chlorpyrifos, although slightly less than with 1000 ppm isofenphos. Termiticides having different repellency/mortality profiles are potentially useful in termite control.
J K Grace

Effects of boron treatments on partially decayed oak and pitch pine heartwood
1996 - IRG/WP 96-30106
This paper reports results of borate based preservative treatment and leaching experiments on partially decayed oak and pitch pine heartwood. Previous experiments have shown little damage is caused to sound timber of these types when treated with Polybor and Boracol 20 preservatives. This experiment was carried out to assess the suitability of selected borate based preservatives for use in historical ships' timbers and therefore the physical effects of these preservatives on such timber was investigated. The results indicate that weight losses incurred due to treatment with Polybor or Boracol 20 are no more damaging than those incurred by treatment with water. Weight changes were more apparent in decayed timber than in sound timber with greater uptakes in non-leached samples and greater weight losses in leached samples. However, comparable weight changes were recorded between water treated samples and preservative treated samples. Dimensional changes were minimal in most cases, the greatest found in non-leached Boracol 20 samples as expected. These results indicate that treatment with these preservatives is suitable for partially decayed oak and pitch pine heartwood.
S McCutcheon, G M Smith, J W Palfreyman, P Durrant

Wood protection by surface treatment of two borate preservatives, TIM-BOR® and BORA-CARE®, for the formosan subterranean termite and eastern subterrean termite
1993 - IRG/WP 93-10044
TIM-BOR® (disodium octaborate tetrahydrate: DOT, Na2B8O134H2O) and BORA-CARE® (40% DOT in ethylene glycol) are two borate products marketed for treating wood in use by brushing or spraying onto the wood surface. The active ingredients presumably diffuse into wood by the 10-15% existing wood moisture. Few data, however, are available to demonstrate the diffusion rate. Su & Scheffrahn (1991) suggested that diffusion rate of BORA-CAREä is quite slow but may be enhanced by the moisture brought in by termites into wood. As there is an increasing interest in using these products for remedial control of subterranean termites, there is a need to understand how do they behave. The object of this study is to examined the termiticidal effects of borate surface-treated wood against the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Koller).
M Toroko, N-Y Su

Laboratory evaluation of borate formulations as wood preservatves to control the subterranean termite coptotermes acinaciformis (isoptera: Rhinotermitidae) in Australia
2001 - IRG/WP 01-30266
The termiticidal efficacy of Borocol (sodium octaborate tetrahydrate), boric acid, bore-ester-7 and tri- methyl borate was evaluated in laboratory bioassays against Coptotermes acinaciformis (Froggatt). Seasoned sapwood blocks of Pinus radiata D. Don, and Eucalyptus regnans (F. Muell) were impregnated with the various borate compounds. There were marked differences in mass loss and mortality rate of the termite used in the bioassay units for different boron retentions. After 8 weeks the result suggested that, borate was toxic to termites in laboratory bioassay even at 0.20% m/m BAE and caused significant termite mortality. However, termites were not deterred from attacking the borate treated timber at higher retentions of > 2.0% m/m BAE. These laboratory results indicated that the minimum borate treatment required to protect timber against termites attack and damage was > 1.0% m/m BAE.
B M Ahmed, J R J French, P Vinden

Comparison of the effects of borate, germanate and tellurate on fungal growth and wood decay
1992 - IRG/WP 92-1533
The tetra-hydroxy borate ion is known to undergo complexation with polyols and has been shown to inhibit dehydrogenase enzymes in this way. It has been previously suggested that this complexation is responsible for the inhibition of fungal growth and the protection of boron treated timber. Other ions that have the ability to complex with polyols have also been shown to inhibit dehydrogenase activity. The effect of two of these ions on fungal growth and wood decay was compared to that of borate. It was found that both germanate and tellurate could reduce fungal growth and provide protection of wood against decay at similar molar concentrations as borate. The results have been used to further develop our understanding of the mechanisms of action of borate wood preservatives and substantiate the theory that borate ion/polyol complexation is responsible for the protection of boron treated timber.
J D Lloyd, D J Dickinson

The probable mechanism of action of boric acid and borates as wood preservatives
1990 - IRG/WP 1450
The tetrahydroxyborate ion [B(OH)4-] acts by complexation with poly-ols and probably attacks decay fungi through extracellular substrate sequestration; intracellular substrate sequestration; enzyme inhibition; and change in membrane function. Work was carried out to investigate this further and to try to explain certain phenomena observed in the area of boron preservation. The effect of Na borate in the presence of different concentrations or various carbohydrates upon the radial growth rate of certain fungi was investigated; along with parallel experiments on the activity of 6-phosphogluconate dehydrogenase as an example of a borate inhibited enzyme system. It was found that upon the addition of certain poly-ols, the inhibitory effect of borate on both fungal growth and enzyme activity could be reduced. These results have been used in the development of our understanding of the mechanism of action of borates as wood preservatives. The commonly held belief that certain mould species are resistant to borates may also need re-evaluation.
J D Lloyd, D J Dickinson, R J Murphy

Fungitoxic effect of the quaternary ammonium compounds preservatives against Basidiomycetes by using agar-plate and agar-block methods
1996 - IRG/WP 96-30118
Results of investigations on the fungitoxic value of three versions of wood preservatives based on the quaternary ammonium compounds (lauryldimethylbenzylammonium chloride, lauryldimethyl-benzylammonium bromide and alkylbenzyldimethylammonium chloride) and borates in relation to the wood destroying fungi have been presented. The agar-plate (screening) and agar-block method were applied. A wide range of the fungitoxic activity of all the three formulations and a very small leachability were proved.
J Wazny, P Rudniewski

Borates as wood preservatives - an environmental, health and safety perspective
1993 - IRG/WP 93-50001-03
Boron compounds are highly effective wood preservatives and have an established safe use in the timber treatment industry. Their widespread background occurrence in nature, low acute mammalian toxicity and useful properties make them versatile active ingredients within today's environmentally aware society. A critical review of health, safety and environmental data on the borates, their use and eventual disposal is used to illustrate many of the issues that have to be addressed by the chemical industry today in assessing the performance of their products in the marketplace. This current state of knowledge is contrasted to the detailed requirements of life cycle analysis with an assessment made of its future role in environmental management.
J B Rainer

Borate diffusion in wood from rods and liquid product. Application to laminated beams
1988 - IRG/WP 3482
In the aim to use borate preservatives (fused rods and boracol) in fields of building construction other than external joineries, tests of diffusion of borate rods and secondary boracol, were carried out on different species of woods exposed to different moisture conditions. Tests were also applied on laminated beams very often subjected to high moisture contents and thus decay of rot fungi. Diffusion was tested in different conditions and in relation, the action of these products was tried with stains and resins for improving strength properties. Diffusion tests on several species of wood confirm the proportionality already observed between moisture content and diffusion of borates in wood for all species. In a short time, test of diffusion on laminated wood showed a good diffusion in two lamella along the glue line leading to another way of boring. There is no problems between these borate products and stains or resins.
D Dirol

Termites in Uruguay; control, prevention and environment
1991 - IRG/WP 1474
When Prof. La Fage's questionaire on termites was received by 1987, few were aware of termite damage in Uruguay and infestations were not much reported. Further contacts between scientists, operators and homeowners, are now shaping the real threat of termite attack. Before letting the problem faIl in the hands of the layman, with all ist environmental risks, it seemed reasonable to: 1) review termite research carried out by Dr. Ana Aber and 2) comment by Ing. Agr. Gustavo Baillod on methods of wood protection from termites, from a practical environmental standpoint.
A Aber, G Baillod

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