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Selective chromate elimination from the storage-drainage-water of a wood impregnation plant
1980 - IRG/WP 3153
With the Enviro-Chrom-Ex process it is possible to eliminate ecologically and economically hexavalent chromium (chromate) from water selectively. The process which is based on the principle of selective ion exchange works with different chromate concentrations and under the presence of other ions, irrespective of the water hardness. The values of water-offtake reach 0.1 mg CrVI at maximum, causing neither pH alteration nor concentration of the salt-content of the water. The plant which has been installed in the Holzimprägnierwerk AG, Waldkirch, Switzerland, for treating chromium-containing drainage-water permits the chromium-containing regenerates to be recycled into the impregnation process. Using this chromate-recycling-process the harmful substance can be eliminated optimally.
O Wälchli, R Ott, R Hugener, E Graf, B Lieberherr


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


Detection of methanogenic bacteria in mining timber
1988 - IRG/WP 1352
Methane explosions in gold mines have been attributed to spontaneous ignition of methane/air mixtures. Biogenesis of methane in the heartwood of diseased trees has been shown, but never in timber in service. Studies were therefore undertaken to establish whether methanogens were present in wooden pit props. Core samples were removed by Pressler increment borer from props in disused areas 2,600 m deep in a gold mine, using strict anaerobic techniques. Samples were milled, homogenised, diluted and used to inoculate methanogen enrichment broth containing radiolabelled NaH14-CO3 in Wolfe tubes pressurised under an 80% H2 / 20% CO2 atmosphere. They were incubated at 38°C for 12 weeks, with intermittent repressurisation. After separation by GLC, headspace 14CO2 / 14CH4 proportions were measured using a 14C detector on a gas proportional counter and methanogenesis rates were calculated. The presence of methanogens in pit props was unequivocally confirmed. Present work investigates the characterisation and identification of these methanogens.
L D Abraham, K Westlake, R I Mackie, J F Putterill, A A W Baecker.


A study of methanogenesis and sulphate-reduction: A possible source of explosive gas mixtures in a gold mine
1989 - IRG/WP 1399
Previous work isolated anaerobic bacteria from timbers and drainage water in a gold mine. The present work identifies the predominant methanogen in the mine ecosystem as Methanobacterium bryantii and sulphate-reducing isolates as Desulphovibrio desulphuricans and Desulphotomaculum antarcticum. Laboratory studies using model systems evaluate the activity of methanogenic and sulphate-reducing bacteria in situ. Most probable numbers (MPN) of bacteria indicate 3.5 x 105 methanogenic and 7.9 x 103 sulphate-reducing bacteria/ml drainage water. MPN values g-1 timber were lower for methanogens but comparable for sulphate-reducers. Laboratory model systems predict methanogenesis as the likely dominant terminal reaction in the mine ecosystem. Maximum calculated rates of methane production were approximately 5 ml methane g-1 wood day-1, however actual rates would never attain this value owing to nutrient limitations and environmental restrictions. Analyses of gas samples extracted from sealed areas verified the presence of methane.
L D Abraham, J F Putterill, A A W Baecker


Wood preservatives: Field tests out of ground contact. Brief survey of principles and methodology
1976 - IRG/WP 269
This paper contains the following spots: 1.: The general need for field tests. 2.: Interests and limits of field tests in ground contact. 3.: Various methods in use for out-of-ground contact field tests. 4.: Fungal cellar tests are they an alternative to above-ground decay exposure tests? 5.: Conclusions.
M Fougerousse


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 2: Report of treatment and installation in Australia
1978 - IRG/WP 440
The purpose of this test and the procedures to be followed have been fully set out in documents distributed by the International Research Group on Wood Preservation and numbered IRG/WP/414 and IRG/WP/420. The prescriptions set out in these two documents have been closely followed.
J Beesley


Field test evaluation of preservatives and treatment methods for fence posts
1985 - IRG/WP 3347
This work presents the field test results after fifteen years exposure of Eucalyptus saligna fence posts treated with six different preservatives and five treatment methods. All the combinations with oil-borne preservatives presented the best results and among the waterborne preservatives, the fence posts treated by immersion method were with the lowest performance in the field test.
G A C Lopez, E S Lepage


Marine testing of selected waterborne preservatives
1987 - IRG/WP 4137
In 1978 a marine test was established at West Vancouver, B C. to determine the performance of selected waterborne preservatives. The preservatives in test were chromated-copper-arsenate (CCA-C), ammoniacal copper arsenate (ACA), a modified formulation of ACA which contained a higher copper content (modified ACA), ammoniacal copper zinc arsenate (ACZA) and ammoniacal zinc arsenate (AZA). The wood species used for the test was red pine. After eight years in test the CCA is providing excellent performance at all retentions, while the modified ACA is showing significant deterioration only at the lowest level. The ACA is performing quite well although it shows signs of surface deterioration at all retention levels. The performance of the ACZA is rated as unsatisfactory at retentions below 32 kg/m³ while AZA was considered to be unsuitable for use in the marine environment.
J N R Ruddick


Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh


A practical method to evaluate the dimensional stability of wood and wood products
1990 - IRG/WP 2342
This paper presents a new simple method to evaluate wood and wood products for their resistance to swelling and to assess wood preservatives for their ability to dimensionally stabilize treated wood exposed to water. Permeable wood of various dimensions and treated with different preserving chemicals have been measured for swelling in the radial and tangential direction during immersion in liquid water. The results indicate that a simple exponential function describing the dimension of the samples during immersion can be used to evaluate both the water-repellency and anti-swelling effectiveness of wood preserving chemicals. The results can be achieved in reasonable time, and the parameters of the function can be determined by a commercial desk-top computer program.
J P Hösli


Testing of wood preservatives against marine borers (Part 1). Method of testing wood preservatives against marine borers (Part 2)
1971 - IRG/WP 37
P C Trussell, C C Walden


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. 2nd Interim Report
1981 - IRG/WP 477
Three reference wood species - Alstonia scholaris, Fagus sylvatica and Pinus sylvestris, untreated and treated with 3%, 6% and 10% CCA and CCB solutions were supplied to all participants for submergence at local sites. Regular examination of samples is being carried out - 6 months, 12 months and then annually for 7 years.
R A Eaton


Modélisation sur maquette du rejet accidentel d'un gaz toxique et inflammable dans l'atmosphere - Emission de type "bouffée d'oxyde d'éthyléne [Water model simulation of toxic and flammable gases in the environment on industrial sites - Puff of ethylen oxide]
1990 - IRG/WP 3576
M Milhe


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 13: Report of fourth inspection (36 months) in Australia
1981 - IRG/WP 481
This report presents the results of the fourth inspection of the IRG/COIPM International Marine Test specimens installed in Sydney Harbour in December, 1977. The inspection took place on 9th December, 1980, after 36 months exposure. Full details of the treatment and installation of the specimens, as well as results of the first three inspections (after 6, 12, and 24 months exposure), have been presented in earlier reports. All inspections of this test have been carried out in accordance with the Working Plan (see IRG/WP/414) except for an X-ray examination of the specimens. This facility is not available at the test station. In conformity with the provisions of the Working Plan, the fifth and sixth replicates of the whole test (i.e. those specimens with '5' or '6' as the final digit of their serial number) were recovered and returned to the United Kingdom after 6 months and 24 months of immersion. Thus, only four replicates remain to be examined at this and ensuing inspections.
J Beesley


Leaching of components from water-borne paints and fungitoxic effects
1995 - IRG/WP 95-20062
Water-borne model paints, acrylics and alkyd emulsion paints, of known composition were leached according to a procedure modified in accordance with ASTM 6271.1. The effectiveness of fungicidal compounds in the painted specimens before and after leaching was evaluated with a biotest in which Penicillium brevicompactum was used as a test fungus. The leaching of the fungicide Troysan Polyphase according to the biotest varied to a high extent depending on differences in paint composition. Fungicide efficiency in relation to paint formulation and fungicide mobility in a paint film is briefly discussed.
J Bjurman


Problem of the treatment of dried sawn spruce building timbers with water-borne preservatives. Interim reports for discussion at the 4th Annual Meeting in West Berlin on 27 October 1972
1972 - IRG/WP 311
One of the most difficult technical problems facing the preservation industry is how to improve the treatment of refractory species of timber such as spruce. Its resistance to penetration, even under pressure' precludes its use for more hazardous service situations, and even in less severe conditions a higher level of treatment would be desirable. The importance of this subject led us to look once again at possible ways of improving treatment.
W Liese, J W W Morgan, T Hof, R O Ullevålseter


Durability of larch (Larix spp.) wood against brown-rot fungi
1997 - IRG/WP 97-10228
Durability of the heartwood of Larix decidua, L. sibirica, L. gmelinii, L. gmelinii var japonica, L. gmelinii var olgensis and L. sibirica x decidua against brown rot fungi Coniophora puteana, Poria placenta and Gloeophyllum trabeum was tested according to EN 113 test method. Parallel samples were used to study the amount and composition of wood extractives. The sample trees originated from the research forest of Punkaharju Research Station. The average age of the trees was 60 years. In addition, from L. sibirica also trees at 25 and 102 years were used. Results show that the durability of larch is depending on species, age of the tree, the wood part (inner or outer heartwood) and fungus. The average durability of larch heartwood was equal to class 3 or 4 (moderately or slightly durable, according to the standard EN350:2) and comparable with the durability of pine heartwood (Pinus sylvestris L). However, the durability of L. gmelinii var olgensis and L. sibirica (102 years old) was on the higher level than that of the other studied species but the durability varied even within the same board. Also the durability of wood from L. sibirica grown in the Russian side (Siberia) was studied. It was equal to that of the trees grown in Finland. The average amount of resin acids of larch heartwood was only about 0.1% (dry weight). In contrast, the heartwood of scots pine may contain up to 4.0% of resin acids. Resin acids are found to inhibit the linear growth of certain fungi. Interestingly, the largest amounts of resin acids (0.3%) were found in the heartwood of L. gmelinii which also showed high durability. The concentration of water soluble extracts (mainly arabinogalactan) of larch heartwood was quite large, varying between 3.2 - 20.5%. The concentration of water soluble extracts in the heartwood increased along the age of the trees. Lowest level of extractives were found in Larix decidua which was also the least decay resistant species. The durability of wood in different targets and the role of different chemical compounds of larch heartwood on decay resistance needs to be clarified.
H Viitanen, L Paajanen, P Saranpää, P Viitaniemi


Results of stake tests on wood preservatives (Progress report to 1974)
1975 - IRG/WP 361
A number of field stake trials on preservative-treated wood have been carried out at Princes Risborough Laboratory from 1928 to the present day, and many of the tests still continue. This paper presents in detail the results obtained to date, covering about 15 000 individual test stakes exposed over the period.
D F Purslow


Effect of water repellents on leaching from CCA treated wood
1995 - IRG/WP 95-50044
CCA treated fence boards brushed with a water repellent finish had consistently lower leaching losses of all CCA components compared to the rate for matched samples without the water repellent. These results are after 12 cycles of simulated rainfall in the laboratory (1800 mm rainfall total) and four months of natural rain exposure in Toronto.
P A Cooper, R MacVicar


Di-sodium fluorophosphate, a new fluorine containing, water-borne wood preservative
1986 - IRG/WP 3373
The physical, chemical properties of Di-sodiumfluorophosphate (Na2PO3F) are compared with those of a trade-mark SF-salt. The opposition of biological activity and toxicological data showed that Di-sodiumfluorophosphate may be a suitable alternative to SF-salts ( based on MgSiF6).
D Seepe, W Metzner


Effects of various preservative treatments on the mechanical and physical properties of plywood
1993 - IRG/WP 93-40007
The technical properties of plywood are related to both the intrinsic characteristics of its composing wood species and the quality and performance of the glue bond which acts as an interface between veneer sheets. Consequently mechanical and physical testing and glue bond strength analysis offer an appropriate means for studying the effect of preservative treatments on the overall quality of plywood. A range of boards was treated with waterborne and oilborne preservatives. Changes in modulus of elasticity, modulus of rupture and tensile strength were noted as well as variations in physical properties. Analysis of the glue bond strength was done by shear strength testing and determination of the amount of wood failure after different ageing procedures.
J Van Acker, M Stevens


Water-based wood preservatives for curative treatement of insect-infested spruce constructions
1998 - IRG/WP 98-30171
On laying down sanitation measures for wooden constructions infested by wood boring insects, we must take into account static risks for the construction - and, thus, for the security of the user - as well as risks for humans and environment due to the chemical preservative compounds of the treated wood. Analyses on many roof constructions made with spruce (Picea abies L.) have revealed that Hylotrupes bajulus L. and Anobium punctatum De Geer have not the significance given to them for decennies. That often allows to replace solvant-based with water-based wood preservatives in old buildings, for the protection of humans and environment. Therefore, a method has been developed in Switzerland for testing wood preservatives with delayed curative efficacy against the house longhorn beetle. Like the European Anobium Standard EN 370 this method intends to prevent the emergence of Hylotrupes beetles. Laboratory tests with diverse water-based wood preservatives available on the market in Switzerland have shown that particularly boron and benzoylphenylurea derivatives containing products get a sufficient penetration in the wood and prevent the emergence of the beetles.
E Graf, P Manser, B Lanz


Leaching of copper, chromium and arsenic from CCA-treated Scots pine exposed in sea water
2000 - IRG/WP 00-50149
A laboratory leaching trial combining a static and a flowing seawater system was carried out to measure the leaching rates of copper, chromium and arsenic from the surface of Scots pine panels vacuum-pressure treated to 3, 6, 12, 24, and 48 kgm-3 CCA. Untreated and treated panels were exposed in flowing seawater for up to 8 weeks followed by 2 weeks submersion in static seawater which was taken for analysis. The study revealed a leaching hierarchy of Cu>Cr>As which supports the findings of other investigators. Over the 8 week leaching trial there was a time-related decrease in the rate of copper and chromium loss. Over the first week of leaching in flowing seawater, the rates of loss of copper and chromium decreased to between one-half and one-seventh, followed by lower rates of leaching over the remaining period of the investigation. In contrast, the rate of loss of arsenic from the wood appeared to increase slightly over the same period. The data are compared with minimal leaching rates of toxins from the surface of anti-fouling paints and are discussed in terms of the fouling communities which are established on Scots pine panels treated to similar target retentions.
C J Brown, R A Eaton


Short-term field test method with accelerated infection of Basidiomycetes in wood
1981 - IRG/WP 2155
In the ŠIPAD - IRC Wood Protection Laboratory an attempt has been made to develop a simple short-term method for field testing out-of-ground contact wood using accelerated infections with Basidiomycetes. This method makes it possible to obtain a preliminary assessment of a preservative's quality and to estimate the possibility of achieving promising results in more expensive long-term tests. The idea was to use water traps (reservoirs) and 50 x 25 x 15 mm³ laboratory infected pine blocks as the substrate to improve the possibility of inoculation of L-joints.
N Vidovic


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 10 from Naos Island, Panama
1980 - IRG/WP 462
Blocks of 3 wood species, Beech (Fagus sylvatica), Scots pine (Pinus sylvestris) and Alstonia (Alstonia scholaris) were exposed at site number 12 at Naos Island, Panama on March 8, 1978 by John R. DePalma. The arrangement of the panels in the exposure site is as shown in Figure 1.
D W French


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