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Soft rot in CCA-treated utility poles in Sweden
1989 - IRG/WP 1398
Soft rot investigations of CCA-treated utility poles (Pinus sylvestris L.) have been conducted throughout large parts of Sweden during 1974-1985. The investigation included 179 utility poles of the State Power Board which had been used for 10-18 years in the different administrative regions from northern to southern Sweden. In addition, 193 telephone poles from the Östersund area and 218 from the Kristianstad area were studied after having been in use for 18-25 years. The soft rot fungi cause two types of attack in wood cells, namely cavities (Type I) and erosion (Type II). In this investigation, soft rot is reported only when cavities of Type I were found. Erosion (Type II) is more difficult to observe, particularly in early stages, and in addition is almost impossible to distinguish from certain other attacks of rot, such as white rot, which may have occurred during storage of the poles before impregnation. In western and central Sweden, minor attacks of soft rot were found after 10-12 years in State Power Board poles embedded in soil in arable land and meadows. Power Board poles in northern Sweden had minor attacks of soft rot after 16-18 years in arable land and also in forest land when embedded in soil. Poles used by the Telecommunications services, all embedded in stone, showed minor and only occasional attacks of soft rot at Östersund (northen Sweden), but considerably more soft rot at Kristianstad (southern Sweden). The Telecommunication poles had been in service up to seven years longer than the poles used by the State Power Board. The localization and spread of soft rot attacks in a pole can vary. There may be many reasons for this, including insufficient impregnation, leaching, etc. The soft rot attacks found in the Power Board poles are always minor and sporadic and none of the investigated poles can be said to imply any safety risk. The same applies to the Telecommunication poles at Östersund whereas those at Kristianstad demonstrated considerably more severe and more frequent attacks. The attacks of soft rot in the Telecommunication poles more frequently occurred internally, more often deeper in the sapwood than in the outermost parts.
H Friis-Hansen, H Lundström


The leaching of copper, chrome and arsenate from CCA-impregnated poles stored for ten years in running water
1978 - IRG/WP 3122
There is no evidence to indicate that the chromium and copper components are leached from the outermost 5 mm of sapwood in poles impregnated with Boliden K33 and Tanalith C and stored in running water for ten years. The arsenic component, however, seems to be leached out during the first few months to an extent of about 20% of the initial amount. The leaching time is dependent on the preservative used.
F G Evans


Draft of a mongraphic card for Serpula himantioides (Fr.) Karst. according to the 'Model Questionnaire for preparation of monographic cards for wood-destroying fungi'
1978 - IRG/WP 174
L Harmsen


Preservación de maderas en Bolivia
1986 - IRG/WP 3360
Este documento ofrece datos generales concerníentes a los recursos forestales de Bolivia, las facilidades existentes para preservación de maderas, la investigación y educación en esa materia. Se proporciona información sobre instituciones vinculadas a la actividad y las perspectivas del tratamiento de maderas en el país.
A S Viscarra


Performance of chromated copper arsenate-treated aspen fence posts installed in Forintek's Eastern test plot from 1951 to 1963
1984 - IRG/WP 3272
Aspen poplar fence posts were pressure treated by the full cell process using three formulations of copper chrome arsenate wood preservative. A total of one hundred and fifty nine of the posts were installed in service in Forintek's Chalk River post plot from 1951 to 1962. During the 1982 general inspection of the post plot all 159 posts were still in service. A groundline inspection was carried out on the material to determine the extent to which decay had progressed during this period. Samples were taken from the surface of tanalith C treated posts and subsequent microscopic examination revealed that soft rot attack was present in the outer portion of posts. The groundline area of posts treated with (K 33), CCA type B and (greensalt) CCA type A were in generally good condition after 22 years and 31 years respectively. Rate of decay was highest for CCA-C tanalith treated posts at 0.3 mm per year with a retention of 3.04 kg/m³ oxides.
C D Ralph


An interim report on trials with 'Boliden K33' and 'Celcure A' in water of different salinities in the Baltic Sea and in the UK
1974 - IRG/WP 406
It was felt necessary to undertake field trials using large test samples exposed in natural water of different salinity in order to determine preservative leaching and to assess the degree of biological attack.
R A Eaton, D J Dickinson


Copper based water-borne preservatives: The use of a thin section technique to compare the protection of wood by copper based preservatives against soft-rot and bacterial decay
1987 - IRG/WP 2286
This paper describes the techniques developed and gives examples of results obtained for the performance of copper based wood preservatives against both the bacterial and fungal hazards.
A M Wyles, D J Dickinson


Treatability of waterstored poles of Norway spruce by sap-displacement and pressure treatment with Boliden K33 and creosote
1973 - IRG/WP 328
Poles of windthrown Norway spruce were stored in bark under water sprinklers for 11-20 months or fully submerged in a lake for 3 years (tab. 1 and 2). Water content after storage is shown in fig. 1 and 8. Treatment with Boliden K33 by sap-displacement (open tank suction) gave a poor result. The Danish requirements of delivery claim a penetration of 20 mm and a net retention of 12 kg/m³ in outer 20 mm sapwood. According to that 22% of the poles stored for 11 months, 53% of those stored for 20 months under water sprinklers and 67% of those waterstored for 3 years were rejected compared with 11% in both control series (tab. 3 and 4). There was no correlation between water content in outer sapwood before treatment and penetration/retention neither for stored nor for unstored poles (fig. 2-7 and 9-10). Pressure treatment (full-cell) of water stored poles with Boliden K33 after air-drying to app. 28% gave a similar poor result (tab 5) while pressure treatment (Rueping) of water stored poles with creosote gave very good penetration as well as retention (tab. 6). The hypothesis is put forward, that the main reason for the unsatisfactory result of the treatment with Boliden K33 might be coagulation of the bacterial slime when mixed with the salt blocking the pathways for the liquid, although the membranes in the tori and the parenchymatic cells are supposed to have been partly destroyed by the bacteria.
P Moltesen, E Borsholt, B Bang


Corrosion of fasteners in treated wood
1971 - IRG/WP 303
Surveying tests for determining the corrosion rates of some metals and alloys in wood untreated as well as treated have been made. It is shown that ordinary steel corrodes faster than other common fastener metals such as copper, brass, aluminium and stainless steel do. Zinc coatings, however, will prevent the steel corrosion effectively provided that the coatings are thick sufficiently. Catalytic decomposition of cellulose by rusting iron is briefly discussed since the expectation of life for a fastener joint is not only depending on after the corrosion remaining cross-section of the fastener but also from the wood deterioration.
T Wallin


Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 6: The length of the primary precipitation period
1975 - IRG/WP 359
The end of the primary precipitation fixation period of CCA preservatives coincides with the first peak in pH versus time. This offers a simple way of estimating the duration of the period. The duration is determined by a number of factors and their interactions, the most important of which are: wood species (anatomy, natural pH, accessibility of reducing agents), preservative type, preservative concentration and temperature. For interpretation of experimental data the effect of these factors is discussed in the light of the chemistry and the mechanism of fixation of CCA preservatives. For a proper handling of the treated timber, knowledge of the duration in actual working conditions is essential.
S-E Dahlgren


Leaching from field test stakes. Part 2: The distribution in and leaching from different parts of test stakes
1994 - IRG/WP 94-50026
Field test stakes treated with Boliden K33 (copper, chromium and arsenic) and Cuprinol Tryck (CT86) (copper and N-alkylbenzyldimethylammoniumchloride) respectively were exposed in ground contact at two different test fields in Sweden and rejected due to decay after 2 to 28 years. Stakes treated with the same preservatives were also exposed during 7 years above ground. The test stakes have been analysed regarding remaining preservatives in different parts of the stakes. As a reference, unexposed stakes were analysed regarding retention and gradient of the two preservatives in the stakes. There was a gradient in the concentration of preservatives in the unexposed stakes, the gradient being greater for CT86 than for CCA. The remaining preservatives in stakes treated with CCA and CT86 differ depending on preservative used and how they were exposed in the field. Least preservative was found in the end grain and there was an indication of a redistribution of preservatives from the inner part of the stakes to the outer part. Leaching from stakes exposed horizontally above ground was not less than that from stakes in ground contact.
F G Evans, B Nossen, M-L Edlund


Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 4: Conversion reactions during storage
1974 - IRG/WP 332
Precipitates simulating those produced in wood by preservative fixation reactions were prepared by the reduction of Boliden K 33 and Celcure AP solutions with hydrogen peroxide and hydrazine. The pH changes on aging at 20 and 50°C were studied and related to the chemistry of fixation previously described. Hydrolysis of copper arsenates may render arsenic acid temporarily water soluble pending precipitation by trivalent chrome liberated by the slow hydrolysis and reduction by wood of chromic chromates. As the reduction of chrome is the primary driving force for the fixation of Cu-Cr-As preservatives, pH changes were observed in sawdust treated with dilute CrO3 solutions under different temperature cycles. The pH is essentially independent of temperature during the first three days when chromic chromates are being formed, but the subsequent pH is highly temperature-sensitive. Part of this effect is due to hydrolysis and reduction and part to generation of acidic reaction products in the wood at higher temperatures.
S-E Dahlgren


Leachability of active ingredients from some CCA treated and creosoted poles in service. A progress report after 10 years testing
1990 - IRG/WP 3627
CCA K33 TYPE B treated or creosoted poles, 10 pieces of each treatment type, have been monitored from the treatment plant to an electricity line, which was build up in Southern Finland in 1978. Preservative retention was determined by taking borings at four different levels: 1.5 m from the top end, 1 m above ground line, ground line and 0.5 m below ground. Determinations were made before setting up the poles and then after 2, 4 and 10 years in service. Also the soil around the poles and in some cases under the but end was analyzed to find evidence of leached heavy metals or creosote oil. After 10 years service the distribution of creosote has been dramatically changed. Only 1/3 of the originally analyzed creosote (150 kg/m³) was found in the borings taken 1 m above the ground level and 1.5 m from the top of the poles. However, the reduction at ground line and below ground was only 10%. This suggests that creosote oil runs down effectively and finally the flow becomes slower when creosote oil reaches the butt end, where the moisture content is much higher and the temperature lower. Significant quantities of creosote oil, 51 g/kg oven dry soil at the highest, were found in soil around the poles and under the but ends. In CCA treated poles arsenic has been leached out in large quantities at every level. At its highest the average loss was 33% at the ground line. In other parts of the poles the average loss of arsenic varied from 21% to 25%. From the top of the poles the average loss of copper was 11%. The other observation points gave figures near 20%. Chromium had been leached out in considerable amounts only from the ground level, where the average loss of 24% was analyzed. The soil samples around the poles showed some high heavy metal contents. The average amount of arsenic analyzed was 180 mg/dm³ (oven dried soil) and the greatest amount detected was as high as 420 mg/dm³. The copper content was 79 mg/dm³ and chromium 65 mg/dm³ in average.
A J Nurmi


Leaching from field test stakes. Results from two different methods of analysis
1993 - IRG/WP 93-50013
Field test stakes treated with Boliden K33 containing copper, chromium and arsenic exposed at three different fields in Sweden and rejected due to decay, have in two studies been analysed regarding leaching and remaining preservatives. The stakes have been exposed during 20 to 43 years. The density of the stakes and content of copper, chromium and arsenic have been determined in the top part of the stakes (above ground) and bottom part (in ground) separately. The density of the stakes after exposure were similar in the top and in the bottom of the stakes while it was lower in the middle, ground line part. Leaching from small sections of the stakes indicate that 23% of copper, 19% of chromium and 25% of arsenic leached from the wood during exposure. Leaching from stakes to the environment, including the preservative in the totally lost decayed part, is, according to the analyses, 50% for copper, -4% for chromium and 36% for arsenic as an average for all stakes. The results from the two studies give different results. This focuses on the importance of sampling and methods of analyses as well as the necessity of being careful when evaluating the results.
F G Evans, M-L Edlund


Fungicidal and termiticidal effectiveness of alkylammonium compounds
1983 - IRG/WP 3232
This paper is related to effectiveness of several AAC's against wood decay fungi and termites by Japanese standardized test methods.
K Tsunoda, K Nishimoto


The variation in electrical resistance in the CCA-treated wood during the fixation
1989 - IRG/WP 3554
The curve commonly used in Scandinavia for describing the fixation period at different temperatures for CCA-impregnated wood is based on investigation by Dahlgren on the pH-variations in a mixture of sawdust and preservative solution. As far as we know there is no such investigation on solid wood. We have therefore measured the electrical resistance in CCA-treated solid wood to see if this will differ according to the different ion consentrations that are in the wood during the fixation process. Our investigation shows that the electrical resistance in the CCA-treated wood varies. At first the resistance will increase, then it will decrease and at last stabilize at a higher ohm-value than in the start. This variation may describe the fixation in the wood and perhaps be used to measure the fixation time at different temperatures for solid, impregnated wood.
F G Evans, B Nossen


A short note on fungal decay in K33-treated poles
1982 - IRG/WP 1169
Soft rot cavities and erosion of the lumen have been found in K33-treated Pinus sylvestris poles from the years 1956-66 by microscopic studies. Poor treatment quality has been proved for some of these poles. The microscopy showed an unusual pattern of attack, and pre-treatment decay is suspected but not yet proved. Sounding the poles and using the Pilodyn indicated decay, but poking did not. Quantification of the attacks was possible only by microscopic studies.
H Friis-Hansen


Performance of CCA treated Eucalyptus round ties
1985 - IRG/WP 3342
After 5.5 years of field exposure in the south of Brazil round Eucalyptus ties treated with CCA type A Oxide (OSMOSE K-33-A) preservative with retentions from 12 to 14 kg/m³ (0.75 to 0.873 PCF) (active ingredient basis) are performing very well. No decay or insect attack was observed in the 100 ties in test in real conditions of use; 10% of ties show incipient checking (what is a natural trend of Eucalyptus ties) and 3% show weaking of the nails.
V J Carlos, F R Niederauer, J P P Wehr


Discoloration of pressure impregnated wood caused by Amorphotheca resinae
1990 - IRG/WP 1438
Amorphotheca resinae Parbery with the anamorph Cladosporium resinae (Lindau) von Arx & de Vries is a cosmopolitan fungus known from aviation kerosene, hydrocarbon contaminated soil and creosoted timbers. In Denmark it causes heavy discoloration on wood treated with waterborne chromate-containing preservatives e.g. CCA-oxide type. The teleomorph produces small spherical fruitbodies widespread on the wood surface causing a more or less black discoloration, while the numerous, dense, conidial heaps of the anamorph appear as irregular greyish-brownish blotches. A survey has shown that both stages appear on freshly CCA-impregnated wood during outdoor storage on all surfaces except on the ends. Stacking with e.g. 15 mm sticks restrains, but does not prevent the problem, and planed as well as sawn surfaces are attacked. On account of its extreme pH-tolerance (from pH 2-9) and its exceptional tolerance towards copper-chromate fungicides, the spores may germinate and the infection take place shortly after the impregnation, and even before fixation of the preservative is completed. The high capacity to grow on impregnated timber mostly increases the spore-count and hence the infection potential on the storage site. Attempts to use different types of additives or surface treatment with mould specific fungicides have not been entirely successful.
F Rune, A P Koch


The relationship between the electrical resistance and fixation of water-borne CCA salts and pressure-treated wood
1991 - IRG/WP 3657
Two investigations at 22°C and 30°C have been carried out. The electrical resistance in the treated wood and chemical analyses of the remaining amount of unfixed copper, chromium and arsenic were investigated. Samples impregnated with water were used as references. To hold the samples moist during the investigation, each sample was wrapped in a polyethylene plastic foil immediately after impregnation. The electrodes were of acidproof steel. The fixation was also checked by chemical analyses. The result shows that the electrical resistance increases during the fixation, as the concentration of the unfixed metal ions decreases, and that it stabilizes at the same time as there are almost no free unfixed metal ions in the samples. It is therefore possible to measure the fixation by using the electrical resistance given, that the temperature and moisture content in the sample is constant.
F G Evans, B Nossen


The performance of metal-chromium-arsenic formulations after 32 to 38 years' in-ground exposure in Australia
2000 - IRG/WP 00-30240
Two trials of metal-chromium-arsenic preservatives were exposed in-ground in Australia. In Trial 1, Pinus radiata stakes treated with Boliden K.33, Boliden S.25, Celcure A, Tanalith C and Tanalith CA were installed at Sydney and Narrandera in 1961/1962. In Trial 2, P. radiata and Eucalyptus regnans sapwood were treated with Celcure A, Celcure A21-N, Celcure A 21-O and Tanalith CA (new) and installed at Sydney and Innisfail in 1966/1967. In Trial 1, all metal-chromium-arsenic preservatives at 8 and 12 kg m-3 gave median specimen lives in excess of 35 years. As none of the stakes treated to 12 kg m-3 with Boliden K.33, Celcure A, Tanalith C or Tanalith CA had become unserviceable, the minimum guarantee period for these preservatives is greater than the present exposure periods. In Trial 2, the four CCA preservatives when impregnated into P. radiata sapwood at 12 kg m-3 gave median specimen lives at Sydney of greater than 32.5 years. With E. regnans sapwood treated to 12 kg m-3, only Celcure A 21-0 gave a median specimen life at Sydney of greater than 32.5 years. At the high decay and termite hazard site of Innisfail, Celcure A 21-0 protected the eucalypt better than any of the other CCA formulations.
G C Johnson, J D Thornton, J Beesley