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Alternative fumigants to Methyl Bromide for wood products: Review of the development and preliminary tests of Ethane Dinitrile (EDN) in Canada
2019 - IRG/WP 19-30743
This paper reviews recent developments and updates in the search for alternative fumigants to ozone-depleting methyl bromide, for wood products fumigation. The absence of alternative treatments may result in significant market disruption if further restrictions on methyl bromide are imposed. This paper reviews key challenges and key attributes of an ideal fumigant and also the status of standardised test methods for evaluation of new phytosanitary treatments and efficacy data required to support adoption by the International Plant Protection Convention and national regulatory bodies. Recent detailed reviews of fumigants have recognised EDN (ethanedinitrile) as a promising product for use on wood products and other commodities. A review of key attributes, history of use and registration of EDN is shared as well as the most recent efficacy data obtained through recent research at FPInnovations. Preliminary data indicate that EDN is very effective against four tree fungal pathogens tested even at a low dosage and very short exposure time (one hour), and was effective against pine wood nematodes in logs within 24 hours of exposure. The lower temperature (10˚C) did not negatively affect the efficacy of EDN as often is the case with other fumigants.
A Uzunovic


The applicability of life cyle analysis and alternative methods in the wood preservation industry
1994 - IRG/WP 94-50023
In the Netherlands, several case studies have been performed using the life cycle analysis method (LCA). This type of research is aimed at an inventory and classification (sometimes including also evaluation) of the environmental impacts of a product, from the raw material to waste stage ("cradle to grave" approach). In a LCA each environmental impact is assessed in terms of, for example, mass of raw material use (kg), energy consumption (MJ), emissions (COx, NOX, SOx, etc.) and final waste (in kg). The critical point in an LCA is the definition of comparable "functional units" for similar products made of different materials with different service lifes. As the LCA method has often proved to be very complex, lime-consuming, expensive and difficult to interpret and translate into practically usefull results, alternative methods are developed. Three methods are described and compared on the basis of various examples. It is hoped that this may be of use as a starting point for further discussion on the suitability of applying the LCA on (preservative treated) timber products.
P Esser, J Cramer


In search of alternative antisapstain chemicals for use in Papua New Guinea
1988 - IRG/WP 3472
The paper presents results of antisapstain field trials from three locations in Papua New Guinea as part of the Research Centre's programme to find suitable antisapstains to replace the hazardous sodium pentachlorophenate. Effectiveness of seven tested chemicals varied between indigenous pines (Araucaria cunninghamii, Araucaria husteinii) and white coloured hardwoods (Alstonia scholaris, Pterocymbium beccarii) but not between sites. The indigenous pines required lower chemical concentration for same level and period of protection than white coloured hardwoods like amberoi and white cheesewood. Period of protection ranged from four weeks to a maximum of 16 weeks depending on chemical concentration and species of timber. Potential chemicals recommended for use as antisapstain include Celbrite T, Busan 1009, Penacide and Woodguard E.S. and Woodguard E.C.
A Oteng-Amoako


Evaluation of the leach resistance and preservative efficacy of novel biocides as surface treatments applied by brush to spruce (Picea abies)
1998 - IRG/WP 98-30170
The comparative leach resistance and preservative efficacy of a number of alternative organic preservatives (available from Zeneca Specialties) and selected commercially available biocides as surface coatings to wood in Hazard Class 3 have been assessed. Two concentrations of test preservatives were applied by brush to Spruce (Picea abies), including formulation and untreated controls. A leaching program was carried out involving the immersion of the treated blocks in water for a scheduled period of time. Blocks were then subjected to biological tests to determine preservative efficacy using the basidiomycetes Coniophora puteana and Gloeophyllum trabeum in a modified EN 113 system; sapstain and mould tests were separately undertaken according to a modified EN 152 test using mixtures of Aureobasidium pullulans and Sclerophoma pithyophila, and Trichoderma harzianum and Trichoderma saturnisporium. Of the four alternative actives tested, one Zeneca development product based on Hexaconazole compared very favourably against the selected commercial biocides tested. An aqueous system based on a Zeneca penetrating aqueous polymer coupled with the Zeneca development active demonstrated favourable performance in relation to an existing solvent based product.
I M Tierney, A Bruce, D C R Sinclair, T Yeates


Elimination of alternative explanations for the effect of iron on treated wood
1993 - IRG/WP 93-30006
Amounts of iron which had previously been found in stakes removed from ground contact reduced decay of untreated wood by four brown-rot fungi. This suggested that the effect of iron may be on the preservative. Analysis of the leachates from CCA- and ACA-treated wood blocks first exposed to rusting iron, then to a brown-rot fungus, showed that the increased decay found in the laboratory for wood exposed to iron was not due to enhanced leaching of the preservative.
P I Morris, J K Ingram, D L Gent


Questionnaire on alternative prophylactic chemicals
1982 - IRG/WP 3189
IRG Secretariat


Preservatives treatment and field test monitoring of spruce pole stock: CCA and fumigant treatments
1990 - IRG/WP 3619
The fumigants trichloronitromethane (chloropicrin) and sodium N-methyldithiocarbamate (SNMDC) were used to treat red spruce pole stock, either CCA treated or untreated, through holes bored through the pole's center. The poles were analyzed for the presence of microorganisms immediately before ground installation and again after installation at a pole test site. Monitoring of fumigant movement in the poles was also performed after one year. Results indicate that both fumigants moved throughout the ground line regions of the poles, although less toxicity to the bioassay fungus was observed in the SNMDC treated poles. Reduced fumigant levels, and more sporadic diffusion was noted in the above ground portions of both chloropicrin and SNMDC treated poles although again chloropicrin exhibited greater toxicity to the bioassay fungus. Despite the variability of fumigant diffusion as determined by bioassay, no decay fungi could be isolated from the treated poles after one year. This was in contrast to high frequency isolation of decay from control poles.
A J Pendlebury, B Goodell


Methods for testing fumigant efficacies against termites
1986 - IRG/WP 1297
Methodologies for testing fumigants against termites are reviewed and factors needed to be taken under consideration for standardization listed. Toxicity should be defined by both direct exposure to the gas and under more practical "barrier" conditions which include test enclosures simulating abiotic surroundings of the termites, i.e. wood, nest material, etc. To observe latent effects, mortality should be recorded periodically after exposure until rates decrease to control levels. Fumigant efficacy should be reported as a function of concentration and exposure time, termed lethal accumulated dose (LAD).
N-Y Su, R H Scheffrahn


Safer alternative reagents for colour differentiation of heartwood and sapwood
1994 - IRG/WP 94-20028
Benzidine and dimethyl yellow reagents have been used for distinguishing heartwood from sapwood in the Pinaceae and Araucariacae families, and in Eucalypt species. Both have been classified as carcinogenic by European and United States authoritites, yet the need for effective heartwood/sapwood differentiation remains, not only in the laboratory but also out in the timber processing chain. Safer alternative reagents have been proposed over the past twenty years, but some of these have since been linked with health problems, and most of the rest lack the specificity and general usefulness of those traditionally used. Recent research has investigated various azo, diazo, and other nitrated reagents. Safe but useful alternative methods of sapwood/heartwood differentiation are being established, and recommendations are made for several timber species.
A Zosars, M J Kennedy


Alternative technologies for wood wastes recycling - Part B: Biotreatment of PCP- and creosote-treated wood
1998 - IRG/WP 98-50101-18 b
Alternative technologies have been investigated to detoxify treated wood. Two classes of organic compounds are studied. Creosote-treated wood are classified in France as dangerous wood wastes. A conventional incineration could be provided for these wood wastes but the cost of this elimination could be very high (> 2000 FFR/ton). For these reasons, we have tested two kinds of new processes as alternative ways. The developed strategy is described in this paper and illustrated by a few examples. Part B - The second one is based on an oxidative degradation of organic compounds directly in the wood: oxidative degradation by fungi. Few examples are presented in this paper. Three fungi are tested directly on treated wood. High levels of contaminants are tested around 0.6 g of PCP/kg and 3.7 g of 8 PAH/kg of wood. Few oxidation products generated by this biological treatment are identified. An ecotoxicological assessment is performed to validate this process. Technical feasibility of these developed processes as well as economic aspects are discussed,
S Legay, P Marchal, G Labat


Studies on the fungicidal effectiveness of a petrol derived product as a creosote alternative
1986 - IRG/WP 3384
This work, appears first because of the necessity to find out a profitable use for a residual product of the petrol pyrolisis, and second, because the lack of high natural durability wood used until now-a-days to build posts and sleepers in creosote lacking countries. Our main objective was pointed to the characterization of this new product and to find out the effectiveness against the wood-destroying fungi, compared to the creosote response.
A M Navarrete, M T De Troya.


Some data on the activity of alternative fungicides for wood preservation
1985 - IRG/WP 3333
Data from laboratory tests against basidiomycete fungi are presented for 9 alternative fungicides in organic solvent formulations and also in water for one product. Results are compared with data for reference preservatives, tributyltin oxide, copper and zinc naphthenates and pentachlorophenol. Of special interest is the apparently better than additive effect of mixing tributyltin naphthenate and Xyligen B, and the promising performance of Armoblen 480, a novel organic solvent formulation of n-alkyl coco-derived quaternary ammonium compounds.
A F Bravery, J K Carey


A laboratory evaluation of the fumigant, sulfuryl fluoride (VikaneR), against the Formosan termite Coptotermes formosanus Shiraki
1982 - IRG/WP 1164
A series of laboratory experiments showed that the fumigant sulfuryl fluoride (VikaneR) was effective against small groups of Coptotermes formosanus Shiraki exposed to the gas directly at temperatures from 20-40°C. At 10°C fumigations failed regardless of initial gas concentration. Very high or total mortality was observed at concentrations of 0.79 cc/L or higher. A second series of experiments was designed to evaluate Vikane's ability to penetrate the carton nest matrix. At 30°C penetration was sufficient to produce high mortality with gas concentrations > 1.06 cc/L. The results suggest that current dosage recommendations for the control of Coptotermes formosanus infestations in structures (4 lbs/1000 cubic feet) are too high and should be reevaluated.
J P La Fage, M Jones, T Lawrence


Fumigant movement in Canadian wood species
1984 - IRG/WP 3296
Pole sections prepared from seven Canadian wood species (Thuja plicata, Thuja occidentalis, Pinus contorta, Pinus resinosa, Pinus banksiana, Pseudotsuga menziesii, southern yellow pine) were fumigated with chloropicrin, methylisothiocyanate and Vapam and the rates of fumigant penetration determined. All three fumigants were applied directly into holes bored radially into the pole sections. Analysis for fumigants commenced after a few days at various sampling distances from the treating point. After three months the test was concluded. Methylisothiocyanate, diffused equally well upwards or downwards in the pole section from the point of fumigation in all wood species, and appears to offer the best potential of the three fumigants as a pole treatment in Canada. When applied directly, chloropicrin initially moved quickly but then the diffusion rate slowed somewhat. Upward movement was fastest in eastern white and western red cedar while downward movement was also rapid in southern yellow and red pine. Chloropicrin movement was rated as good in Douglas-fir but poor in jack pine. Diffusion of chloropicrin was severely retarded in lodgepole pine. In general Vapam movement was slow at first, and then increased with time. Diffusion rates for all wood species were similar except for relatively rapid upward movement in red and southern yellow pines.
J N R Ruddick


Effect of fumigant residue in aerated wood blocks on the spore germination of decay fungi
1991 - IRG/WP 2382
Fumigants are increasingly used in several countries for remedial treatments of transmission poles to increase the service life. The present study was initiated primarily to test the remaining toxic effects of spruce (Picea rubra) wood, fumigated with chloropicrin (trichloronitro methane) or MIT (Methyl isothiocyanate) after long period of aeration, on the spore germination of decay fungi. This study indicates that spore germination of decay fungi is more sensitive than mycelia for these fumigants. An assay involving spores could therefore complement the earlier proposed open and closed tube bioassays for assessment of remaining ability to prevent reestablishment of decay fungi in fumigated wood. This assay is sensitive both to bound wood residues contributed by the fumigants as well as to fumigant vapor.
J Bjurman, B Goodell


Alternative timbers to Iroko (Milicia excelsa) for various end-uses: Ghana’s offer
2004 - IRG/WP 04-10518
There are hundreds of timber species indigenous to Ghana and several exotic species have been extensively planted. The timber industry in Ghana is very important to the country’s economy. Despite its small size relative to the world trade in timber products, it has the potential to be a driving force in the development of the Ghanaian economy. The industry is currently going through a period of change and restructuring which is largely brought about by the need to address the issues of a reducing resource and to use the available resource more efficiently and to greater economic benefit by promoting the lesser used species as alternatives to the over-exploited primary species and also by developing the tertiary processing sector. Iroko (Milicia excelsa) is one of the primary species currently facing extinction and Dahoma (Piptadanistrum africanus), Ekki (Lophira elata), Kusia (Nauclea diderrichii) and Papao (Afzelia bella) are lesser-used species being promoted as good alternatives to Iroko for various end uses. Properties (mechanical, biological) and volumes of these species are compared to those of Iroko.
S A Amartey, Zeen Huang, A Attah


Alternative technologies for wood wastes recycling - Part A: Supercritical extraction of PAH compounds from wood wastes
1998 - IRG/WP 98-50101-18 a
Alternative technologies have been investigated to detoxify treated wood. Two classes of organic compounds are studied. Creosote-treated wood are classified in France as dangerous wood wastes. A conventional incineration could be provided for these wood wastes but the cost of this elimination could be very high (> 2000 FFR/ton). For these reasons, we have tested two kinds of new processes as alternative ways. The developed strategy is described in this paper and illustrated by a few examples. Part A - The first one is based on the use of supercritical fluid as C02 to solubilize organic compounds as organochlorine compounds and Polycyclic Aromatic Hydrocarbons (creosote) from treated wood. Kinetics results of this extractive process are presented on the basis of 200 g of wood.
L Schrive, C Perre, G Labat


The effect of alternative pre-conditioning procedures on the durability of wood based board materials to decay fungi
1997 - IRG/WP 97-20105
In the biological testing of wood based board materials it has been shown that exposure of boards in a closed vessel system may lead to inaccurate results due to the build up of volatile substances that inhibit the test fungi. It is thought that this is a transitory effect of freshly manufactured boards. In the European standard for testing fungal durability of board materials which is currently under development (DD-ENV 12038:1996), a leaching pre-conditioning method is used to remove this effect. A variety of alternative ageing procedures have been studied, including natural weathering, leaching and evaporative procedures, to determine the most appropriate pre-conditioning protocol for the decay test. Our results show that there are procedures which are more efficient, and possibly more meaningful in terms of effectiveness or appropriateness of regime for use on board specimens.
S F Curling, R J Murphy, J K Carey


Status of Work on OECD Test Guidelines for Emissions of Wood Preservatives to the Environment
2005 - IRG/WP 05-50224-3
In April, 2003, OECD published an ESD on wood preservatives that provides guidance on how to estimate emissions: 1) during the wood preservative application processes and storage of treated wood prior to shipment; and 2) from treated wood-in-service. The ad hoc Expert Group that developed the wood preservatives ESD identified the need to develop Test Guidelines to estimate the amount of biocides leaching from treated wood. A proposal to develop these Test Guidelines was submitted to the OECD Working Group of National Coordinators of the Test Guidelines Programme (WNT), and the WNT agreed at it May 2001 meeting to include this project in the Work Plan and Schedule of Activities. The current work on these Test Guidelines is being carried out b the Secretariat in collaboration with drafting group WG 27 of the European Committee for Standardization (CEN). A first draft of the guidelines (for leaching of active ingredients from wood both in and not in contact with water/soil) was circulated in February 2003 to the National Coordinators for comment. Germany, with funding from the European Commission (EC), had agreed to carry out some pre-validation work that could address some of the issues raised in the comments from the National Coordinators. Germany invited project partners, the OECD Expert Panel, members of CEN TC38/WG 27, industry and governmental agencies to participate in a meeting held in September, 2004 to design the pre-validation work. Once the pre-validation work has been completed and the text for the draft guidelines modified, the guidelines will be submitted to experts in OECD countries for comment. The final drafts of the guidelines will be submitted to the Joint Meeting for declassification.
W Jakob


Artificial weathering exposure as an alternative for standard ageing according to EN 84 (leaching) and EN 73 (evaporation)
2002 - IRG/WP 02-20254
In order to verify potential weaknesses of wood preservatives fungal tests are carried out after ageing of wood preservative treated test blocks. The European standard EN 599 as a framework for efficacy assessment of wood preservatives includes the use of two ageing methods prior to fungal testing, namely a leaching method (EN 84) and an evaporation method (EN 73). The European research project "F.A.C.T." aimed amongst other objectives to provide in more realistic alternatives for both ageing methods. Artificial weathering systems generally used to assess the weathering resistance of exterior coatings was looked at as an alternative. For this purpose artificial weathering devices were selected which besides a control of temperature and light also allow for the impact of moisture by means of water spraying. UV cabinets with spray option were used to evaluate the effect of ageing of three wood preservatives: a waterborne Cu-HDO preservative, an oilborne triazole combination and a TBTO reference preservative. Based on EN 113 Basidiomycete testing of aged specimens a range of equivalent UVS systems proved to be suitable as an alternative ageing system prior to EN 84 and EN 73.
J Van Acker, M Grinda, D J Dickinson


An alternative method for the determination of lignocellulolytic enzymatic activities of white rot fungi
1998 - IRG/WP 98-10261
Some lignocellulolytic activities of wood decay fungi can be evaluated in an indirect way through the study of the decolorization that white rot fungi produces in culture media in the presence of dyes. In this assay, ten dyes were selected, which were added in concentrations of 0.00 1% - 0.003% (P/V) to four-day cultures of Trametes versicolor containing 1% of beech sawdust in a basal salt medium. After the addition of the dye and at seven-day intervals, aliquots were taken in aseptic conditions in order to determine the following parameters: pH, loss of colour, and laccase and Mn-peroxidase activity. All of the cultures and determinations were carried out in triplicate and contrasted with noninoculated controls, as well as with controls that were inoculated, but with no stain added. The results obtained showed that the fungi produced decolorization in all of the cases. The linear regression analysis of the data of residual color (as absorbance), contrasted with the lignocellulolytic activities, showed significant regression coefficientes (p<0.05) in the cultures with Methyl Red, Safranine, Crystal Violet and Blue Eosin. In an additional experiment, sonicated and non-sonicated extract were incubated with Methyl Red solutions (significant regression coefficient) and Bromophenol Blue (non-significant regression coefficient), independently, for three hours. The results showed that there are no notable differences between the sonicated samples and those that were not sonicated in a medium with Methyl Red, whereas in a medium with Bromophenol Blue, decolorization was produced only in the presence of the sonicated extract. This would indicate that the decolorization of Methyl Red can be carried out by extracellular components of the culture, while Bromophenol Blue requires the action of intracellular components to become degraded. This might explain the significant correlation mentioned earlier.On the other hand, the nature of the dyes may influence the magnitude of the activities described: thus it is seen that with Bromophenol Purpel and Crystal Violet, significantly higher values of activities than those of the control without a dye are obtained, while with Malachite Green, the activity is significantly lower.
D Muñoz-Mingarro, F Llinares, F Rubio, M Yuste, C Rodríguez-Borrajo, J Jiménez, M T De Troya


Comparison of Temporal Changes in Metal Leaching and Aquatic Toxicity from Wood Treated with CCA and Alternative Preservatives
2005 - IRG/WP 05-50236
This study compares the temporal variation of chemical leaching and aquatic toxicity of wood treated with chromated copper arsenate (CCA) and other copper-based wood preservatives (alkaline copper quaternary (ACQ), copper boron azole (CBA), copper citrate (CC) and copper dimethyldithiocarbamate (CDDC)). Treated wood blocks were leached for 21 days and the leachate collected was analyzed for preservative chemicals and aquatic toxicity. The measured rate of copper leaching was fit using the recently proposed diffusion model for predicting preservative leaching rates. An unpreserved wood sample was tested as a negative control. In general the predicted values for flux rate were on the same order of magnitude as calculated using the experimental data. In natural water, several physical and chemical factors may affect the bio-availability and toxicity of chemicals. Copper concentrations and resulting aquatic toxicity obtained using two natural waters as leaching solutions were found to be lower compared with data obtained using de-ionized water as the leaching fluid.
B Dubey, T G Townsend, G Bitton, H M Solo-Gabriele


Prevention of non-microbial sapwood discolorations in hardwood lumber: chemical and mechanical treatments
1997 - IRG/WP 97-30137
Sapwood discolorations in hardwood lumber that are non-microbial in origin result from the formation of pigmented starch-like granules in ray parenchyma cells. These discolorations can be prevented by treating unseasoned lumber with an antioxidant (sodium bisulfite). Exposing unseasoned lumber to microwaves or treating logs with fumigants also will prevent these discolorations. Subjecting unseasoned lumber to mechanical stresses (compression and/or vibration) also prevents sapwood discolorations of non-microbial origin. A machine to mechanically stress lumber and thereby prevent these discolorations has been built and is being field-tested at cooperating sawmills.
T L Amburgey, S Kitchens


Ecotox Testing of Leachates as an Alternative Approach for Environmental Impact Assessment of Wood Preservatives
2002 - IRG/WP 02-50185
Driven by the implementation of the EU Biocidal Product Directive (BPD) in the environmental assessment of treated wood different methodologies and test strategies are at present under discussion within industry, regulatory authorities and standardizing comittees. Test procedures for the analytical determination of emissions to different environmental compartments according to exposure scenarios are suggested for international harmonization. In addition ´fate and behaviour´ modelling as well as the PEC/PNEC consideration are proposed to produce an environmental risk assessment of treated wood. As an alternative approach direct ecotoxicological testing of leachates is presented with leachates from solvent based preservatives treated timber as example. Daphnids as very sensitive bioindicators exhibited differences due to the included biocides of the preservative formulation tested as well as the leaching procedure used. The methodology of direct ecotoxicological testing as an alternative to PEC/PNEC comparison is discussed for suitability in wood preservation.
H-W Wegen


Field evaluation of alternative antisapstain chemicals
1982 - IRG/WP 3198
Seven alternative antisapstain formulations containing four different active ingredients were field tested during the summer and fall of 1981. The test was designed to evaluate the potential long term effectiveness of PQ-8 (Chapman Chemical Co.) containing copper-8-quinolinolate, Busan 30 (Buckman Laboratories) containing 2-(thiocyanomethylthio)benzothiazole, BL2398 (Buckman Laboratories) containing a mixture of 2-(thiocyanomethylthio)benzothiazole and methylene bis-thiocyanate, Xyligen K30F (BASF) containing the potassium salt of N-nitroso-N-cyclohexyl hydroxylamine and three formulations, Polyphase (Troy Chemical Corp.), Woodbrite NTX (Van Waters & Rogers) and Argosy (Aero-Pak Ltd.) containing 3-iodo-2-propynyl butyl carbamate as active ingredient. The tests were evaluated after three months and again after five months. Protection of hemfir lumber comparable to a 0.65% w/w chlorophenoxide treatment was achieved with 0.8% active PQ-8, 2.0% active Busan 30, 0.8% active BL2398, 1.0% active Polyphase, 1.0% active Woodbrite NTX and 1.0% active Argosy treatments. Xyligen K30F treatment at the 1.0% active level was ineffective.
D V Plackett


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