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A comparison of soft rot, white rot and brown rot in CCA, CCP, CCF, CCB, TCMTB and benzalkonium chloride treated Pinus radiata IUFRO stakes, after 9-15 years exposure at five test sites in New Zealand
1991 - IRG/WP 1485
The aim of this study was to determine if decay type varies significantly between five field trial test sites of different soil type, aspect and climate in 9-15 year old, replicate CCA, CCF, CCP. CCB, TCMTB and AAC treated IUFRO stakes. A visual on-site assessment of decay type on every test stake was made and observations confirmed by microscopical examination. Regression analyses were used to determine significant differences of percentage frequency of occurrence of each rot type between sites and preservatives. Large differences in percentage frequency of occurrence of rot type were evident between sites. One site was dominated by brown rot (85%) and two were dominated by soft rot (99 and 91%). The fourth site had intermediate proportions of brown rot (40%) and soft rot (71%) but had the second highest occurrence of white rot (32%) (highest = 37%; lowest = 11%). The fifth site was distinct in that a large proportion of stakes (69%) had both well established brown rot and soft rot. Stakes at the other four sites tended to have only one rot type. Some highly significant preservative effects were also found. Possible causes of these differences are discussed in terms of inter-site soil type, climate and other differences.
R N Wakeling

Use of biossay to determine CCF and CCB preservative retentions in treated Pinus sylvestris
1984 - IRG/WP 2216
The retention of each a copper/chromium/boron and copper/chromium/fluoride preservative in pressure treated pinepoles was tested by bioassay using Aspergillus niger as test fungus. Small samples of 5 mm³ were taken from various depth of the poles and placed on potato-dextrose agar plates. The inhibition of fungal growth depends on the preservative retention in the cubes and corresponds closely to results obtained by atomic absorption spectrophotometry.
J C Moreschi, H Willeitner

Some aspects of laboratory and field testing methods of antitermite wood preservatives
1973 - IRG/WP 235
Various methods for laboratory testing of antitermite activity of wood preservatives are described. The results of simultaneous tests of three water-borne preservatives, according to the various methods are discussed, and comparison is made with results of field tests on the same three preservatives, showing a fairly good accordance between laboratory results and field results.
M Fougerousse

Migration of active ingredients from treated timber into fresh water
1991 - IRG/WP 3669
Spruce roundwoods and segments were treated with three different wood preservatives. Two of them containing copper and chromium the other one free of chromium. After fixation (3 weeks, 20°C) the specimens were leached by using artifical rain or by shaking the segments for one hour in contact with demineralized water. The water was analysed for the relevant elements of the preservative tested. Leachability of the components from the copper-chromate treated wood decreases. After 4-8 leaching cycles an almost constant migration of wood-preservatives, depending on the leaching method and the pH-value of water applied, was determined for the chromate containing preservatives. In the course of leaching cycles a constant rate of migrated copper from the preservative free of chromium was determined after 4 - about 17 leaching cycles. After 16 leachings of the segments the leached copper as calculated on the copper retention was determined to 1.6 - 5% for the chromium containing preservatives and about 22% for the tested variation of the new type of preservative.
H Klipp, H Willeitner, K Brandt, A Müller-Grimm

Imprégnation de bois ronds par déplacement de sève à Madagascar
1975 - IRG/WP 352
M Fougerousse, P Guéneau

Tests on preservation of wood against marine borers
1976 - IRG/WP 417
The Instituto del Legno has carried out for some years a series of trials about the biodeterioration of wood in the sea. The investigations included the settlement and activity of marine borers, the natural durability of indigenous and tropical woods and the preservation of wood for marine use. This paper reports the trials on the effectiveness of some preservatives in protecting wood against marine borer attack. The trials were carried out at Follonica station, where some investigations had shown that untreated pine samples submerged in the sea were totally destroyed by marine borers within 1 year. Follonica station, latitude 42° 55' North and longitude 10° 45' East, is situated on the Tyrrhenian sea. The recorded temperature varies between 12°C (January to March) to 25°C (July to September), salinity between 37 to 38% and pH about 8. The borers observed in wood were: Nototeredo norvagica Spengler, Bankia carinata Gray, Limnoria tripunctata Menzies and Chelura terebrans Philippi.
A Gambetta, E Orlandi

Development of a method for testing wood preservatives with soft rot fungi
1975 - IRG/WP 250
Although the first publications on experimental soft rot attack date back 20 years ago, so far no test method for evaluating the efficacy of wood preservatives against soft rot attack (Ascomycetes and Fungi Imperfecti) has been generally accepted. The reasons are diverse and the shortcomings and the disadvantages of the methods described are well known and have repeatedly been discussed. The soil burial method developed by G. THEDEN (1961) using non-sterilised soils with their natural flora of micro-organisms is said to be poorly reproducible. One possibility to work with clearly defined test fungi and easily reproducible test conditions was developed and described by P. KAUNE in the BAM as the vermiculite burial method. For the further development of this method, in the past years numerous investigations have been made in the BAM to select test fungi and define a test arrangement. Their results will be summarised below.
M Gersonde, W Kerner-Gang

Water-borne wood preservatives against marine borers. Results from NWPC marine trials started in 1972 and 1976
1990 - IRG/WP 4162
The paper presents the results from NWPC (Nordic Wood Preservation Council) marine trials started in 1972 and 1976. The trials are carried out according to the NWPC Standard No. "Marine test - a test against marine wood boring organisms in sea water". The test site is Kristineberg Marine Biology Station on the west coast of Sweden. The wood blocks used in the trials were made from sapwood of European redwood (Pinus sylvestris L.). European beech (Fagus sylvatica L.), European birch (Betula spp.) and Norway spruce (Picea abies (L.) Karst) were also used to a minor extent. In all, 19 water-borne wood preservatives were tested. The preservatives consisting of copper-chrome, copper-chrome-arsenic, copperchrome-boron, copper-chrome-phosphorus and tributyltin oxide gave best performance. The ammoniacal copper preservatives failed to protect the wood against marine borers.
Ö Bergman, C Lundberg

Life cycle analysis of utility poles. A Swiss case study
1995 - IRG/WP 95-50040-05
Use of preservative-treated wood products faces increasing public and political pressure because of environmental concerns regarding the chemicals used to protect the wood. However, critics usually focus only on one single aspect of the whole life cycle of treated wood products, disregarding other environmental effects of timber utilization. To evaluate the ecological consequences of wooden utility poles (CCF/CCB impregnated roundwood and glulams) and their alternatives of reinforced concrete and steel, a life cycle assessment was conducted. Based on data from existing Swiss electricity transmission lines, a comprehensive inventory was established of all extractions from, and emissions to the environment caused by each process step. This inventory data was linked to possible environmental impacts using various aggregation methods. An evaluation was made for single poles as well as for whole transmission lines. The results show that impregnated roundwood utility poles in fact have certain environmental benefits when considered over their whole life cycle.
T Künniger, K Richter

The effect of creosote and Basilit on the boards of 4 wood species against destructive fungi in Northern Iran
1989 - IRG/WP 3555
The results of the experiments conducted on the boards of maple, hornbeam, alder and beech, show that under the humid and moderate climate condition of Northern Iran, after 30 months, the witness samples were about 10% destructed by fungi, especially by Schyzophyllum commune and Coriolus versicolor. The impregnated samples by Creosote Basilite using Rueping and Bethell methods, were quite intact. There was no difference between these two chemicals. Among destructed boards, maple and hornbeam containing the most sugar and starch materials are more senitive than beech and alder. Until 50% destruction of witness samples, the experiments will follow up.
D Parsapajouh

Influence of the peeling on the absorption in the sap displacement method
1990 - IRG/WP 3626
Results of tests on the Eucalyptus and pine fenceposts treated by sap displacement method are presented. Freshly cut post 2 m in length and 8 to 16 cm in diameter were placed for 6 days with their butt ends down in water soluble preservative solution (CCF) to a depth of about 65 cm, and these were inverted and kept in the same way for 3 days more. The treatment began a few hours after felling. The absorptions obtained in partially and totally barked fenceposts were compared. In both timber species, the barked fenceposts absorbed approximately two and a half times more preservative than the other fenceposts partially barked.
M V Baonza Merino

Practicability of bioassays in the evaluation of environmental risks in wood protection
1996 - IRG/WP 96-50071
As an example for the proofing of the practicability of bioassays in the evaluation of environmental risks in wood protection the ecotoxicological behaviour of CCF-impregnated timber was examined. After vacuum pressure impregnation specimen from shaped pine poles were tested on ecotoxicological effects of leachable compounds using sensitive aquatic organisms like fish, Daphnia and algae as bioindicators. According to proper impregnation the influence of leachable compounds from treated timber was significantly lower when compared with the acute aquatic toxicity of the preservative and its ingredients. This indicates the existance of safety factors and allows a differentiated estimation of environmental risks for impregnated wood. A general proposal for an ecotoxicological screening procedure in wood protection is presented.
H-W Wegen

Impregnation of roundwoods by sap-displacement in Madagasca
1975 - IRG/WP 352 E
The use of roundwoods is already very important in Madagascar and steadily increasing for the following applications: - posts, electricity and telephone line supports (medium voltage) - stakes, piles for civil engineering structures, bridges, gantries, road and port works, etc. - construction of houses (posts, frameworks, piles, etc.) and rural buildings (sheds, stables, piggeries) - fence posts, vine stakes, posts for cattle pens, etc. As in all tropical, climates, the agents of destruction of standing timber are numerous and very active. Under these conditions, the natural durability of currently used species does not exceed a few years. It is necessary therefore to consider treatments for securing prolonged service life, without too much cost increase, so that users do not choose substitutes such as metal or concrete. The treatments in pressure vessels can only be applied, from an economical point of view, in regions near impregnation plants. But rural areas, too remote and badly served by transport, cannot be supplied in this way, because of the high transportation cost which has to be added to that of the treatment. This is why for a long time attention has been given to treatment processes and preservatives which can be applied without industrial equipment, at small scale sites, scattered eventually mobile. For a reasonable cost, these techniques confer to the wood a sufficient resistance to the agents of destruction, the most virulent of which are decay fungi and termites, in some cases both, depending on the area. Research in this direction has been carried out on the treatability of some Madagascan species using sap displacement.
M Fougerousse, P Guéneau

Effectiveness of copper/chromium salts as wood preservatives against Limnoria tripunctata Menzies in laboratory tests
1977 - IRG/WP 431
During the last joint meeting of IRG and COIPM a co-operative programme of tests with copper/chromium salts as wood preservatives against marine borers was discussed and agreed. In this connection the results of a laboratory test in the BAM with Limnoria tripunctata Menzies will be of interest. But as the respective paper is written in German (H. Kühne; G. Becker: Laboratoriumsversuche über die Wirkung kupferhaltiger Schutzsalzgemische auf die Holzbohrassel Limnoria tripunctata Menzies) (Material u. Organismen 5 (1970) No 4, 307-319) a comprehensive summary is given in English for IRG-COIPM members.
H Kühne

Strength properties of preservative treated pine and spruce wood after super-heated steaming
1984 - IRG/WP 3313
Possible changes of strength properties of CCF pressure impregnated pine and spruce with subsequent steaming at 110°C respective 120°C for 30 min were examined. For spruce analysis of variance indicated that none of the processes had a significant effect on bending strength, compression strength and the corresponding modulus of elasticity as well as on impact bending strength and shear strength radial resp. tangential to the grain. For pine no changes in the bending strength and the compression strength could be detected. The impact bending strength of unsteamed or steamed impregnated samples decreased with 12% compared to non-treated controls due to the brittleness of the salt-impregnated timber. It could be proved that neither steam treatment of 110°C nor of 120°C for 30 min. alone causes a significant change of strength properties of pine and spruce. Arising variations can be explained from anatomical wood properties as well as salt deposits in the samples as a consequence to impregnation.
R-D Peek

Microbial decomposition of salt treated wood
1993 - IRG/WP 93-50001-22
Specialized microorganisms which are able to convert fixed inorganic preservatives from treated wood into water soluble components are investigated. A number of brown rot fungi like Antrodia vaillantii have been isolated from cases of damage and examined under unsterile conditions with CCA-, CCB-, CCF- and CC-treated wood at retention levels of at least 50% higher than recommended for wood in ground contact. Depending on the kind of fungus, preservative retention, wood particle size, culture conditions and duration Cr and As can be almost completely leached from the treated wood. Cu reacts with oxalic acid to a compound of limited water solubility.
R-D Peek, I Stephan, H Leithoff

Treatment of poplar plywood with solvent and water-borne preservatives
1989 - IRG/WP 3538
Poplar as a light hardwood is appropriate for plywood production. Owing to its low natural durability it is generally recommended to preserve it in all conditions where risks of fungal attack may be present. A research project has been carried out on preservative treatments of plywood commodities. Parameters studied were various treatment cycles, three types of plywood, and a number of solvent and waterborne preservatives. Impregnated materials were exposed to different fungi in order to assess the decay resistance. It was concluded that no special treating cycles were needed to achieve the target uptake levels. However, based on the toxic limits for some of the preservatives the biological tests releaved the need for higher loadings. This points to the different approach needed for plywood preservation. Though small differences in the treatability of the three types of plywood were observed, the glueline interface generally did not have a significant effect on penetration.
J Van Acker, M Stevens

Marine trials with water-borne salts and organotin compound
1986 - IRG/WP 4128
Pinus sylvestris blocks treated with water-borne salts (CCA, CCB, CCF) and organotin compounds (TBTO, TBTCl) were submerged in the sea at Follonica station. The results obtained after 12 years of immersion are presented. The samples treated with CCA, CCB and CCF at the lowest concentration (2%) were destroyed after 7-9 years and the samples treated with CCB and CCF at the highest concentrations (4%, 6%), which were tested for a longer time than CCA treated samples, were destroyed after 11-12 years. The samples treated with organotin compounds did not show any attack by molluscan borers after 12 years with the exception of those treated with TBTCl at the lowest concentration (0.5%). The organotin compounds were less effective against crustacean borers.
A Gambetta, E Orlandi

A comparison of the migration behaviour in soil of different waterborne wood preservatives and their leachates
1997 - IRG/WP 97-50091
Lysimeter tests were carried out on water-soluble wood preservatives and on wood preservative components leached out of impregnated wood. The purpose of these tests was to determine the extent to which the migration behaviour of environmentally relevant ions in the soil is influenced under comparable conditions. The results clearly show that the groundwater is especially at risk when wood preservatives are allowed to penetrate the soil unhindered (worst case). Anions, such as chromates for example, are a particular risk as they are scarcely adsorbed by the ground matrix and can therefore enter the groundwater supply very quickly. On the other hand, copper, for example, is adsorbed so firmly by the soil that only negligible concentrations are found in the eluate. Its risk to the groundwater can therefore be ruled out. The lysimeters were filled with leachates containing preservatives from treated wood. The copper, zinc, chromium and fluorine ions were mainly analysed in the top layers of soil, thus indicating that in practice "only" regional soil contamination is to be expected. On the other hand, the concentrations of these ions found in the eluate are of the size if those which occur naturally, as was expected. The following ranging can be concluded for the tested water-soluble wood preservatives and their leachates containing preservatives from treated wood with regard to a possible risk to soil water or groundwater: wood preservative >> impregnated wood (wood preservative not yet fixed) > impregnated wood (wood preservative fixed).
E Melcher, R-D Peek

The fate of salt preservatives in facility yard soils and decontamination of soils and drainage waters
1993 - IRG/WP 93-50001-25
Extensive studies during the past 10 to 15 years revealed that noticeable amounts of preservative components may be released in the environment by dripping off or by rain prior to fixation unless adequate precautions are taken. Therefore, soil and groundwater contamination especially from chromium-VI compounds but also from other inorganic and organic constituents exist in impregnation plants, possibly endangering the soil and groundwater ecosystem. The actual risk potential originating from chromium-containing wood preservatives in a practical situation are to be studied in the frame of a comprehensive research programme sponsored by the German Ministry of Research and Technology (BMFT). Accompanying laboratory investigations are performed with the aim of assessing the various types of water-soluble wood preservatives with respect to whether or possibly which compounds remain mobile und thus bio-available in the soil. Special attention is drawn to the question as to which effective constituents are adsorbed to soil particles depending on the mineralogical-geological composition of the soil, and at what situation the retention capacity for effective components of different soils would be exceeded. The results of the pilot study and of parallel running laboratory tests serve as a basis of deterioration analyses for grading and assessing the endangering potential in the ecosystem and shall provide a basis for the choice of adequate remedial concepts and measures to avoid such environmental impacts.
R-D Peek, H Klipp, K Brandt

Fundamentals on steam fixation of chromated wood preservatives
1988 - IRG/WP 3483
Weathering of treated wood directly after impregnation leaches up to 2% of copper-chromate-containing wood preservatives. Almost total fixation of Cr+6 is achieved by steaming the treated wood at 100°C to 120°C, preferably 110°C. To initiate such spontaneous fixation 85°C to 90°C inside the wood are essential, which requires heating times ranging from 20 to 80 min, depending on timber species, retention, required depth of fixation, and steaming conditions. Lower temperatures without steam cause an increased leaching, due to drying effect without promotion of fixation. For softwoods the efficacy of the preservative is not effected; in the case of hardwoods treated with CCA, a certain reduction against softrot fungi was noticed. Both bending and compression strength of pine and spruce remained unchanged. A carefully performed steam fixation will effectively reduce pollution.
R-D Peek, H Willeitner

Persistance of active ingredients in treated wood
1993 - IRG/WP 93-50001-20
Disposing of chemically protected waste wood implies the distinction between surface and pressure treatment. Considering that barked round-wood merely contains, after 7 months open storage, less than 30 g per ton of bark or 25 mg per ton of sapwood, depending on the type of insecticide, the bark or sapwood shavings may be incinerated normally, according to less severe legal prescriptions than for pressure treated wood. Past use poles, destroyed by fungi, will indeed have to be disposed of in specially equipped incineration plants, which respond to strict requirements regarding the waste air.
E Graf, P Manser, S Rezzonico, B Zgraggen

Sawn timber of fir (Abies alba Mill.) - Treatability and usability for the Hazard Classes 3 and 4
1999 - IRG/WP 99-40147
Within a national research project, tests on the treatability on sawn timber of fir (Abies alba Mill.) in oscillation pressure, vacuum pressure and double-vacuum processes have been worked out with 95 trunks taken from 3 different altitude levels (up to a height of 590 metres, 600 to 990 metres and over 1000 metres) and from 4 different regions of Switzerland. As the treatability of round wood can be compared with that of spruce (Picea abies L.), the sawn timber shows a considerably higher retention and penetration of the preservative. According to the standard EN 350.2 this wood can be classified into treatability class 2. With a vacuum pressure process a much better quality can be reached than with an oscillation pressure treatment. The treatability can be influenced by the origin of growth, as far as wet heart appears increasingly on a fir location; lumber with wet heart has a four times higher retention. The altitude of growth had no significant influence on the impregnation quality. The good retention and penetration of the preservative makes these wood species suitable for weather exposed outside constructions of solid wood or glued laminated timbers (for example bridges, acoustic and face protection walls, fences and toys). As the heartwood of fir is impregnated too, an adequate or even longer durability than with Scots pine (Pinus ssp.).can be obtained for treated construction wood.
E Graf, T Bör

Field fencepost test of several species treated with water-borne preservatives by rural methods
1986 - IRG/WP 3385
Fencepost field results in ground-contact treated by rural methods: immersion-diffusion and sap displacement by evaporation are analyzed. Copper-chrome-arsenic and copper-fluor-chrome preservatives were used in two concentrations. The wooden species studied were: Pinus pinaster, Eucalyptus globulus and Quercus rubra. For each of the test units decay index evolution was analyzed after five years exposure. At the moment, the best results are obtained with the immersion-diffusion method.
M V Baonza Merino

Performance of copper-chrome formulations in ground contact in five test sites in New Zealand
1996 - IRG/WP 96-30113
Copper-chrome-arsenate (CCA), copper-chrome-boron (CCB), copper-chrome-fluoride (CCF) and copper-chrome-phosphate (CCP) have been tested at four retentions each in ground contact (25 x 50 x 500 mm³ radiata pine sapwood stakes) for 16 years in five test sites in New Zealand. Results to date show that test site characteristics have a marked effect on relative performance. In a warm and wet site (annual rainfall 2000 mm) where soft rot and brown rot predominate, there is very little difference in performance between formulations at equivalent total active element retentions. In drier sites (annual rainfall 1250-1500 mm), where brown rot is more active, CCA is significantly more effective than the other formulations and in a very wet site (annual rainfall >3500 mm) CCB and CCP are most effective formulations. Results are discussed in relation to how climate and soil characteristics influence composition of the fungal flora and their combined effects on preservative efficacy.
M E Hedley, R N Wakeling, J Foster, B E Patterson

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