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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

Remedial ground-line treatment of CCA poles in service. A progress report after 28 months' testing
1988 - IRG/WP 3481
Remedial treatments of CCA-treated poles in service with incipient soft rot were carried out with boron rods, boron/glycol solution, boric acid paste, copper/creosote paste and a commercial product (DFCK paste) respectively. The micro-flora before remedial treatment and 6 months after as well as the spread of chemicals in the poles were reported in Document No: IRG/WP/3388. In this progress report the changes in the micro-flora after 12 and 28 months are detailed together with the results of chemical studies on the spread of borates after 28 months. Studies have also been carried out on the sensitivity to borates of some fungi as well as the soft rot capacity in pine wood of some fungi isolated 28 months after treatment. The results concerning the micro-flora after 28 months are encouraging for boron rods, boron acid paste and especially for DFCK-paste. The spread of borates after 28 months was very good. In sapwood the average concentration, as boric acid, exceeded 2 kg/m³ in treated zones in poles treated with boron rods and 1.0 kg/m³ in treated zones in poles treated with boric acid paste.
B Henningsson, H Friis-Hansen, A Käärik, M-L Edlund

Fixation of CCA in Pinus sylvestris after kiln-drying
1990 - IRG/WP 3594
Tanalith C Paste is 98% fixed and Tanalith Oxide C is 99% fixed irrespective of whether treated Pinus sylvestris is kiln or air dried. A schedule suitable for kiln drying of CCA treated Pinus sylvestris is described.
P Warburton, J A Cornfield, D A Lewis, D G Anderson

Diffusion of a copper naphthenate/boron paste through Douglas fir heartwood
1991 - IRG/WP 3671
Groundline wraps are an important portion of the remedial treatment strategies for protecting utility poles in North America from surface decay. The compositions of these wraps have recently shifted away from pentachlorophenol and creosote to formulations containing copper naphthenate and boron. These formulations have not yet been extensively tested, although the chemicals have been used for many years in other applications. Radial and longitudinal diffusion of the components of a copper naphthenate/boron paste was studied in Douglas-fir heartwood blocks at 30 and 60% moisture content. Longitudinal orientation and higher moisture levels resulted in greater diffusion of both components. Boron diffused faster than copper naphthenate over the 6 month test period, but the degree of copper movement was substantial. The results suggest that this copper/boron paste can readily diffuse through normally refractory heartwood. Field trials are underway to evaluate the biological efficacy of this formulation.
P G Forsyth, J J Morrell

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

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

Remedial treatment of creosoted railway sleepers of redwood by selective application of boric acid
1980 - IRG/WP 3134
An ideal preservative for remedial treatment must primarily be characterized by two requirements. First, it must have an ability to diffuse and distribut evenly into the wood and secondly, it must be fixed properly so that it does not leach out too fast. However, these two characteristics conflict with each other, and the choice of preservative must of necessity be a compromise. Wood preservatives based on boric acid have excellent diffusibility but like the fluorides they are not appreciably fixed in the wood. It was therefore considered important to study the progress of the boric acid diffusion in creosoted sleepers in full scale tests. Impregnation equipment and technique were of course also of interest in the study. The tests started in September 1970, when approximately 100 creosoted sleepers, after being in service for 13 years, were treated with a boric acid paste and installed in a test track at the marshalling yard at Nässjö (the Nässjö test). To obtain an indication of the effect of the treatment for a track in use and to study the developed method and equipment, in April 1974, approximately 1000 seventeen years old creosoted sleepers on the main line south of Kungsbacka (the Kungsbacka test) were treated. Samples of timber have been extracted from the sleepers on the two sites and analysed after different times of exposure in order to follow the progress of diffusion of the boric acid. In total, more than 2000 chemical analyses have been carried out by Borax Holdings Ltd in England. In order to establish whether the boric acid treatment adversely affected the electrical resistance of a sleeper, a small scale trial was carried out with 11 sleepers from the Nässjö test. In May 1971 they were installed in a test track near the SJ Civil Engineering Laboratory in Stockholm. As the study progressed, a large amount of data from the chemical analyses was obtained, and to evaluate the fungicidal effect of the boric acid in the sleepers a series of biological tests was carried out at the Swedish University of Agricultural Sciences in Uppsala. The Swedish Wood Preservation Institute has been responsible for the final revision and editing of the results as well as compiling this report.
C Bechgaard, L Borup, B Henningsson, J Jermer

BG- an easiest preservative paste and its effective diffusibility in timbers for indoors and outdoors uses
2001 - IRG/WP 01-30253
After application of a newly formulated paste "BG-1" on all surfaces of air-dried lumbers, the boron have been found diffused completely in permeable and impermeable hardwoods at the rate of 12 mm radial thickness per week. The new paste may be a solution to protect lumbers being used or to be used under cover where timber is susceptible to termite and borer attack. The new cost effective paste was found to sterilize wood through diffusion and found suitable for pole maintenance at groundline and above groundline, e g cut ends, drilled holes, woodpecker's holes etc. as well as suitable for indoor use too. Compared to boron rods for internal diffusion in presence of moisture, this non-aquous boron based formulation will be more effective for external remedial treatment of problematic hardwood and softwood poles because external treatment is more critical to protect a sound shell required to carry maximum bending load. It is evident from field study that the remedial treatment is mandatory for all hardwood poles within first 10 years or earlier. Application of preservative paste during first installation of hardwood poles is an extra precautionary measure in the climatic condition similar to Bangladesh.
A K Lahiry

Environmental safeness of 60% and 72% concentrated CCA-C solution and paste for wood treatment
2012 - IRG/WP 12-50284
In this study 30-years practical and observational experience of the present author about using of 72% concentrated CCA-C paste for preparing treating solutions and for treating wooden poles, anchor logs and cross arms has revealed that the 60% concentrated CCA-C solution is superior to the 72% concentrated CCA-C paste regarding solubility, homogeneity, cleanliness, treatability, sludge formation, problems of plant operators. Often certain percentage (1% to 2%) of 72% concentrated CCA-C paste cannot be dissolved in water and remain in solution as suspended minute particles that helps formation of sludge on treated products and at the bottom layer of reserve tanks. Therefore, 60% concentrated CCA-C solution has been found to be environmentally and economically safer than 72% concentrated CCA-C paste and has been recommended to use 50% to 60% concentrated CCA-C solution stopping using problematic 72% concentrated CCA-C paste as a source of treating solution.
A K Lahiry

Brief introduction to a research project on preparations of various paste formulations from boron, fluoride and copper for supplemental treatments
2022 - IRG/WP 22-30759
Wood preservatives to be used for supplemental purposes are present in various forms such as powders, liquids, rods, pastes, or gels. Boron compounds have been receiving a lot of attention in supplemental treatments since they have good mobility in wood. Application of boron compounds via internal treatments is vital to stop decay to be occurred inside the wood since large wood elements are too thick to treat well the inner parts of wood. Diffusible chemicals such as borates move through moisture in the wood but do not move in dry wood. This paper evaluates a recent research project on boron-based paste formulations prepared from boron mineral ulexite and some other actives such as fluoride and copper to be used in supplemental treatments in timber structures. In the project, six different paste formulations have been developed. The pastes have been introduced into the holes in Scots pine sapwood specimens conditioned at different moisture content levels. The study is in progress and boron diffusion is now being observed at three assay zones across the specimens after 7, 30, 60 and 90-day-incubation at room temperature.
E E Soytürk, D Bakır, E Terzi, C Köse, S N Kartal