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Report of meetings of remedial treatments Sub-group held in Madrid, Spain during 27-28 April 1988
1988 - IRG/WP 3502
J N R Ruddick
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
Diffusion of fused borate rods in top ends of poles
1989 - IRG/WP 3518
Diffusion tests of fused borate rods were carried out on extremities of sapwood poles in service. Rods were set in drills under the cone with or without addition of liquid Boracol 40. After one year of weathering, a good diffusion in the slice under the cone and even below the slice and in the cone itself was observed in Scots pine and spruce poles. The rods were still intacts and constitute, in fact, a reserve of boric acid for the future. This type of treatment would be satisfactory as secondary treatments of poles in service.
D Dirol, J P Guder
A new approach to the maintenance of wooden railway sleepers. (Second report)
1988 - IRG/WP 3492
The microenvironment and micro-ecology of wooden railway sleepers was investigated to assess their condition to determine the necessary treatment, repair and replacement criteria. In this report the efficacy of the secondary preservative treatment with solid boron rods is discussed and the development of an in-situ, nondestructive test method based on the creation and assessment of structural dynamic vibrations is described.
W Beauford, P I Morris, A M Brown, D J Dickinson
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.
Evaluation of a solid remedial wood preservative containing boron and fluorine
1993 - IRG/WP 93-30022
The fungicidal and termiticidal effectiveness of a new rod form of diffusible remedial wood preservative, containing disodium octaborate tetrahydrate/sodium fluoride and marketed as Polesaver Rod, was evaluated in laboratory tests against three species of basidiomycete fungi (Coniophora olivacea, Pycnoporus coccineus, Perenniporia tephropora) and two species of subterranean termites (Coptotermes acinaciformis, Mastotermes darwiniensis). The rods were dissolved in water and various dilutions were used to treat specimens of Eucalyptus regnans sapwood using a full-cell process, providing retention levels which ranged from 1.2 to 37.4 kg/m³. Soil jar decay tests have shown the remedial preservative is toxic to Coniophora olivacea and Pycnoporus coccineus at a retention of 1.2 kg/m³ solubilised total rod and 2.3 kg/m³ for Perenniporia tephropora. Mean% mass loss data showed that a retention between 2.3 and 4.7 kg/m³ was necessary to protect specimens from significant attack by Coptotermes acinaciformis and between 9.3 and 18.7 kg/m³ for the more voracious Mastotermes darwiniensis. Laboratory diffusion tests on several species of eucalypt hardwoods have confirmed the capability of the preservative's active ingredients to diffuse through both heartwood and sapwood in concentrations toxic enough to inhibit fungal growth. In addition, field testing has shown that after eight months, significant radial and longitudinal diffusion of boron and fluorine was achieved from rods introduced into Eucalyptus obliqua pole stubs. Samples taken within the diffusion zone indicated loadings of up to 4.1 kg/m³ of boron and 5.2 kg/m³ of fluoride.
K J McCarthy, J W Creffield, L J Cookson, H Greaves
The secondary treatment of creosoted electricity poles with fused boron rods
1988 - IRG/WP 3485
After preliminary trials selected poles were treated at the groundline with fused boron rods. Early samplings showed that movement was slow in the dry heartwood but after six years the distributions obtained indicate that the system has merit for the treatment of the heartwood of poles in service.
D J Dickinson, P I Morris, B Calver
Performance if internal remedial treatments to arrest fungal attack in poles and large timbers
2018 - IRG/WP 18-40834
Internal remedial treatments have been used to arrest internal fungal attack in utility poles and other large timbers. Water diffusible systems and volatile fumigants have both been used for this purpose. While both work, it is important to understand the performance attributes of each system. This paper reviews the literature on both systems and makes recommendations for future research.
J J Morrell
The efficacy of remedial treatments for controlling fungal decay in window millwork used in the United States
1987 - IRG/WP 3432
Conventional window millwork was subjected to basidiomycete decay by inoculation and sampled for active growth of the decay fungus before and eight months after remedial preservative treatment with fused disodium octaborate rods (IMPEL) at boric acid levels of 1.5 and 4.0 kg/m³ or liquid bifluoride injections (IMPROSOL) at 1 kg/m³. The elimination of decay fungus after remedial treatment was nearly 100% effective in all treated material regardless of remedial treatment used or chemical loadings. By contrast, isolation of decay fungi in the control samples increased overall from 27 to 69%. Color reagent dye tests for diffusion indicated excellent distribution of chemicals in wood material where moisture contents exceeded 25%.
M G Dietz, E L Schmidt
A suggestion for the improvement of the chemical protection of wooden poles
1987 - IRG/WP 3445
Insufficient drying of white poles in Sweden causes inadequate penetration of the impregnation compounds, CCA salts and creosote, in a varying proportion of the treated poles, and with pretreatment decay present, sooner or later, internal fungal attack in the ground-line zone of the standing poles is the result. The application of a diffusing fungicide in the ground-line zone in connection with the erection of poles would protect the "pockets" of untreated sapwood and thereby create a more uniform performance, delaying the necessity of early inspection and eliminating a considerable number of premature interchangements of poles.
Performance of boron and fluoride based rods as remedial treatments in Douglas-fir poles
1995 - IRG/WP 95-30070
Boron and fluoride are widely used for remedial internal treatments, but their use in North America has been limited. Recently, however, interest in these chemicals has increased as the result of concerns about the risks of fumigant usage. The performance of boron or a boron/fluoride combination was assessed in Douglas-fir poles over 1 to 3 year periods. Both chemical formulations diffused well through the wetter, groundline zone of the poles, although the initial release rate of the boron in the fused borate rods was somewhat slower than that found with the combination. Chemical levels in the groundline zone remain above those required for control of active fungal attack. Chemical levels above the groundline varied widely reflecting the moisture variations present and highlighting the need for adequate moisture to produce uniform diffusion.
J J Morrell, P F Schneider
The effect of different concentrations of polesaver rods on the survival of selected decay fungi in liquid culture
1998 - IRG/WP 98-30166
An in-vitro method was developed to determine the effect of solutions of Polesaver Rods on the survival of selected decay fungi. Polesaver Rods are a diffusing preservative treatment containing fluorine and boron designed for the internal remedial treatment of power poles. Two white-rot fungi, Perenniporia tephropora and Trametes versicolor, and two brown-rot fungi, Polyporus verecundus and Gloeophyllum abietinum, were grown in flasks of liquid growth media containing one of eight different concentrations of Polesaver Rods. Subcultures were made from the mycelium in the flasks after 1 day, 1, 2, 4 and 8 weeks exposure. Sampled mycelium was inoculated onto a malt agar medium and emergent fungi were identified to determine survival of the original inoculum. Media aliquots were taken at each sample time for confirmatory analysis of boron and fluorine concentrations as well as the determination of residual glucose. All four test fungi exhibited increasing susceptibility to the Polesaver Rod solutions with time. Exposure for one week to the highest concentration (1.6% Polesaver Rod) was sufficient to kill all test fungi. Three of the fungi survived 2 weeks exposure to a 0.4% Polesaver Rod solution. After 8 weeks exposure to this concentration only one of the test fungi that was selected in this experiment for its known tolerance to boron, Polyporus verecundus, was able to survive.
M A Powell, T Deldot, C McEvoy
A chemical and mycological evaluation of fused borate rods and a borate/glycol solution for remedial treatment of window joinery
1983 - IRG/WP 3225
The possibility of using fused borate rods (Impel Borpatron) and a borate/glycol solution (Boracol-40) for depot impregnation of window joinery has been examined in a co-operative project between The Swedish Forest Products Research Laboratory, The Swedish University of Agricultural Sciences and Prolignum AB. The fused Impel rod is a glassy rod composed of disodium octaborate which readily dissolves and is distributed as bore acid when introduced into moist timber. Boracol-40 is a liquid containing disodium octaborate dissolved in glycol which has an ability to disperse in timber with a moisture content below 25%. The study involved treatment of a large number of windows in service as well as chemical and biological laboratory tests on the distribution and protective effect of the preservatives. In the field study about 100 windows, selected at random in various buildings in the Stockholm and Gothenburg areas were treated in-situ.
M-L Edlund, B Henningsson, A Käärik, P-E Dickèr
Remedial ground-line treatment of CCA poles in service. A final report after 60 months' testing
1989 - IRG/WP 3534
Remedial treatment of CCA treated utility poles of Pinus sylvestris with incipient decay was carried out in 1983 and the results of chemical and microbiological analyses 6 months after treatment were reported in Document No: IRG/WP/3388 while microbiological studies 12 and 28 months after treatment as well as chemical analyses of poles treated with boron rods or boric acid paste 28 months after treatment were reported in Document No: IRG/WP/3481. 60 months after the treatment a final study was carried out on the remaining two poles left from each treatment. The study included isolations of fungi as well as chemical analyses of poles treated with boron rods, boric acid paste and borate/glycol.
B Henningsson, H Friis-Hansen, A Käärik, M-L Edlund
The effect of glycol additives on diffusion of boron through Douglas-fir
2000 - IRG/WP 00-30235
Boron is highly effective against a variety of fungi and insects and is able to diffuse with moisture through wood. Diffusion decreases sharply at lower moisture contents, a characteristic that limits the potential use of this material as a remedial treatment for arresting internal decay. One approach to improvi ng boron diffusion is the simultaneous addition of glycol, which is presumed to enhance boron diffusion. In this study, the potential effects of glycol addition were explored by adding glycol plus boron (Boracol 20®, Boracol 40® or BoraCare®) or Timbor® and fused boron (Impel rods®) to produce a desired boric acid equivalent in each pole. Boron movement was assessed by periodically removing increment cores for chemical analysis. All of the supplements improved the diffusion of boron through Douglas-fir wood. Timbor®, which does not contain glycol, resulted in the most even distribution of boron throughout the poles while Boracol 40® seems to have increased boron diffusion to the point of loss from the poles.
C M Freitag, R Rhatigan, J J Morrell
A new approach to the maintenance of wooden railway sleepers. (Final Report)
1992 - IRG/WP 92-3724
The micro-environment of wooden railway sleepers was investigated to assess their condition, to determine the necessary treatment, repair and replacement criteria. In the final report the secondary preservative treatment of wooden sleepers with solid boron rods is discussed; the complete development of an in-situ, non-destructive test method based on structural dynamics analysis is described. The maintenance of wooden sleepers using these techniques and the resulting cost benefits within the railway industry are also discussed.
W Beauford, A M Brown, D J Dickinson
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.
The influence of drilling patterns on the distribution of toxicants from Polesaver Rods in hardwood poles
1994 - IRG/WP 94-30051
Polesaver Rods are solid rods of wood preservative that are used as a groundline maintenance treatment to control biodeterioration in hardwood transmission poles in Australia. The rods are inserted in holes that are drilled in a prescribed manner to distribute the toxicants into the critical groundline region of the poles. To determine the influence of drilling patterns on the distribution of toxicants five test drilling patterns, including the prescribed method, were assessed in unseasoned pole-size stubs of tallowwood (Eucalyptus microcorys F. Muell). The distribution of toxicants was visually appraised and is reported for three of the drilling patterns. The results indicate that drilling patterns influenced the toxicant distribution. Two of the trial patterns appeared to provide improved distribution of toxicants for specific applications when compared with the prescribed pattern.
W D Gardner, C N McEvoy
A comparison of the diffusion of boron from two types of solid preservative rods into the heartwood of 3 Eucalypt pole species
2000 - IRG/WP 00-30227
The ability of boron to diffuse from polyborate and boron/fluoride rods through the heartwood of three eucalypt pole species (blackbutt, red ironbark and spotted gum) was examined. The aim was simply to determine the effects of rod type, wood species and time on the longitudinal diffusion of boron in eucalypt heartwood. Rapid diffusion of boron from polyborate or boron/fluoride preservative rods occurred when rods were placed in the wet heartwood of the three eucalypt species. The diffusion generally increased with time and the level of diffusion was greater in the lower density species (blackbutt and spotted gum) than in red ironbark. The effect of rod type on diffusion was generally statistically insignificant. Hence, after 52 weeks there was no statistically significant difference in the diffusion of boron from the two rod types in any of the 3 pole species tested. The diffusion of boron was greater in pole stubs that contained pockets of decayed wood and this may account for why field data suggests that solid preservative rods are highly effective in controlling internal decay in eucalypt power poles.
P J Beutel, P D Evans
Distribution of boron from fused borate rods in Douglas-fir transmission poles
1996 - IRG/WP 96-30112
The diffusion of boron from fused borate rods (disodium octaborate tetrachydrate) was monitored over 42 months in CCA-treated Douglas-fir transmission poles. The boric acid equivalent was estimated by the curcumin/salicylic acid color test on increment cores removed from the poles. Moisture content of the poles was quite variable but was always above 20 percent. The percent of increment core length showing boron was also variable with time of sampling from individual poles and between poles. Diffusion of boron increased until 18 months then decreased slightly at 30 and 42 months. Boron was almost always detected downward from the treatment holes at a distance of 25 cm. Likewise, boron was usually detected laterally from the insertion hole at a distance of 7.6 cm. Movement of boron upward from the insertion holes was often nil and not exceeding 5 cm. Thus, because of the variable penetration of boron in the Douglas-fir heartwood, untreated areas are present that are susceptible to decay.
T L Highley, F Green III, W F Finney
Treatment of wood with boron esters
1995 - IRG/WP 95-30087
The treatment of wood and wood products with boron esters is reviewed. The physical and chemical characteristics of boron esters affecting the treatability of wood are discussed, in particular thermal decomposition and rates of hydrolysis. The uses and methods applying boron esters as wood preservatives include: (i) Solutions of boron esters for remedial and diffusible treatment of wood; (ii) solid boron esters for remedial treatments; (iii) vapour treatments using low boiling points esters, for example trimethyl borate; (iv) solutions of boron esters for light organic solvent preservatives (LOSP) treatment.
J Romero, P Vinden, J A Drysdale
Potential for migration of boron from fused boron rods used as internal remedial treatments of utility poles
2014 - IRG/WP 14-50301
The distribution of boron in Douglas-fir utility poles and in the surrounding soil was assessed over a 54 month period following application of fused boron rods. Boron levels in the wood never reached the levels that might be predicted if diffusion were to produce a uniform chemical distribution, nor did levels in the soil suggest that boron was becoming more concentrated. The results suggest the need for further studies to better delineate boron distribution in wood and to better understand the rate at which bron moves from wood and intro the surrounding soil.
M Konkler, C Freitag, C S Love, J J Morrell, J Renfroe
Aspects of diffusion of boron through wood
1984 - IRG/WP 3298
Boron compounds have been shown to be toxic to a wide range of wood destroying insects and fungi. They are cheap, have low mammalian toxicity and their application in the treatment of wood does not demand specialized equipment. These attributes make them specially attractive to developing countries. Currently, however, little is known about the mechanism of diffusion of boron through wood. Effective treatment with boron preservatives requires good understanding of how the preservatives diffuse through wood. This paper presents a research proposal with the overall objective of determining the relative importance of structural wood components in determining diffusion rates.
Utilization of curcumin for detection of presence of boron in wood
1982 - IRG/WP 3191
It has been shown that curcumin is not a reliable reagent for detecting boron in wood that has been attacked by fungi
Strength loss associated with steam conditioning and boron treatment of radiata pine framing
1987 - IRG/WP 3438
The combined effect of included defects and wood moisture content on the strength loss of second rotation radiata pine framing following conventional steam conditioning is investigated. The green Modulus of Elasticity (MOE) is reduced by approximately 13% after steaming. When dried after steaming, however, neither the MOE nor MOR is significantly different from unsteamed dried controls.
M J Collins, P Vinden