IRG Documents Database and Compendium


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Safety technique in wood preservation
1974 - IRG/WP 54
S N Gorshin, I G Krapivina, B I Telryatnikova


Proposed method for out-of-ground contact trials of exterior joinery protection systems
1981 - IRG/WP 2157
Methods for testing the efficacy of preservative treatments for exterior joinery are described using the format of a European Standard. Commercially used treatments applied to jointed test units (L-joints) which are then protected by conventional finishes are exposed to normal outdoor hazards out of ground contact. Assessment is made a) by determining eventual failure through decay and b) by destructive examination of replicate treated and untreated units, after increasing time intervals, rating comparative performance in terms of wood permeability increase and the progress of microbial colonisation.
J K Carey, D F Purslow, J G Savory


Field performance of wood preservative systems in secondary timber species
1997 - IRG/WP 97-30152
The objective of this ongoing study is to evaluate the performance of new, potential, and standard wood preservative systems in secondary North American timber species. Eleven preservative systems were evaluated in this study - ACQ Type B, Copper Citrate 2: l, CDDC, chlorothalonil/chlorpyrifos, copper-8-quinolinolate, tebuconazole/chlorpyrifos, RH287, propiconazole/chlorpyrifos, copper naphthenate, CCA. and creosote. Field evaluations are being performed with ground contact field stakes and termite-specific testing in Hawaii, along with laboratory soil bed tests. The major wood species used with all the systems and evaluation methodologies are loblolly pine, northern red oak, tulip poplar, and cottonwood. More limited evaluations (field stakes only) are being conducted with eastern hemlock, red maple, and sweetgum. Information is presented from laboratory soil bed, field termite, and field stake evaluations. There is good correspondence between soil bed and field stake results. The more highly developed preservative systems and those in an AWPA P9 Type A oil carrier tend to perform better, and there can be a strong affect on performance from the wood species.
P E Laks, K W Gutting, R C De Groot


Physical barriers and bait toxicants: The Romeo and Juliet of future termite control
1991 - IRG/WP 1503
Soil chemical barriers are considered by some to be the most important technique for protecting buildings against subterranean termites in Australia (and elsewhere), providing a barrier against termite penetration. However, there is no such thing as a barrier that is 100 per cent +protective. And given the worldwide problems of using organochlorine termiticides, public awareness of chemical pollution and contamination to the environment, emphasis on physical barriers has been refocussed. In the event of such barriers being penetrated, the use of suitable bait systems and toxicants is considered a fruitful "back-up" strategy in future termite control measures. Such a system is environmentally friendly, has wide public acceptance, and readily marketable.
J R J French


Evidence supporting the use of termite baiting systems for long-term structural protection
2000 - IRG/WP 00-10377
The efficacy of the Sentricon Colony Elimination System containing Recruit II termite bait (0.5% hexaflumuron) in controlling active subterranean termite infestations has been demonstrated in numerous studies. This baiting system and other termite baiting systems are now widely used, and generally accepted, tools for remedial termite control in North America, Hawaii, and other parts of the world. The role of baiting systems in prevention of termite damages and long-term structural protection, however, is more controversial than their use in remedial control. We discuss three lines of evidence in support of the use of baits for long-term structural protection: (1) successful control of termite populations with baits in remedial studies allows a conceptual leap to preventative efficacy, since baits target colonies and populations and cannot be evaluated directly for prevention in the manner of soil insecticide barriers; (2) field and laboratory studies demonstrate that termite colonies feed on multiple resources and continue to radiate outward from each of those resources in search of additional food, increasing the likelihood of rapid bait discovery; and (3) results of our long-term field studies over the past decade demonstrate that newly invading termites will reuse existing galleries in the soil left by earlier colonies that lead to monitoring stations, were detected in monitoring stations, and were subsequently eliminated without any noticeable evidence of structural infestation or damage.
J K Grace, N-Y Su


Blue stain in timber in service. Results of co-operative tests to compare different artificial weathering systems 1981-82
1983 - IRG/WP 2193
The paper describes results of the third phase of co-operative laboratory experiments comparing the effects of different artificial weathering systems on chemicals to control blue-stain in service. Atlas, Xenotest and Marr equipments are shown to give essentially the same results for 5 of the 6 chemicals tested.
A F Bravery, D J Dickinson


Natural Durability Classification Systems Used Around the World
2009 - IRG/WP 09-10694
Around the world natural durability is classified in different ways. The nature and rigor of the tests used to measure durability, the method of classification based on these data, and use of these classifications to specify end uses or predict service life all vary. This can lead to confusion among people not familiar with the various systems used. This review describes the methods used to classify naturally durable wood around the world.
R Stirling


Blue stain in service on wood surface coatings. Part 2: The ability of Aureobasidium pullulans to penetrate wood surface coatings
1992 - IRG/WP 92-1557
The ability of Aureobasidium pullulans to penetrate seven different wood surface coatings was examined. Eight isolates of Aureobasidium pullulans were used. Following penetration, light microscopy was used to examine the effect of the fungus upon the coating, and growth at the wood-film interface. The fungus showed different growth capabilities with different types of surface coatings. Some isolates were able to penetrate alkyd based coatings, but were unable to grow in the film. In contrast, after penetration through latex based coatings several isolates were able to produce growth in the films themselves.
P R Sharpe, D J Dickinson


Soft rot tests
1983 - IRG/WP 2206
At the IRG meeting in Turkey it was proposed that developments in testing preservative-treated wood in unsterile soil according to techniques variously described as "fungus cellar", "soil-bed", or "accelerated field simulation" be considered along with conventional laboratory procedures as the basis for a standard test. Before formulating any co-operative test programme it is essential to examine in detail the specific requirements of a standard test method as it applies to soft rot control. This paper contains 12 comments to provoke discussion with the aim of crystallising opinion on these specific requirements and hopefully to outline an experimental programme of work.
J A Butcher


Xenon simulation of natural weathering of external joinery preserving - Finishing systems
1992 - IRG/WP 92-2412
Semitransparent wood stains ('lazures') for external joinery have developed by means of product combination towards complete wood finishing systems that are easy to applicate, have a good weathering resistance and low maintenance cost. The search for enhanced formulations and the possibilities to standardize these products or treatment systems are always facing long periods of weathering tests. Extensive research was conducted to compare natural weathering with artificial ageing, using a scheme based on two cycle units commonly used for artificial weathering and intermediate low temperature exposures. Statistical analysis of test results showed good similarity between both natural weathering and Xenon ageing
J Van Acker, M Stevens, M Nys


Resistance of painted wood to mould fungi. Part 2. The effect of wood substrate and acrylate paint systems on mould growth
1997 - IRG/WP 97-10234
Resistance of acrylate paint systems on different types of pine and spruce sapwood to mould fungi was studied. Dipping into the preservative prior to painting, a primer with and without a fungicide (propiconazole + IPBC 0.50 + 0.2%) and a topcoat with and without a fungicide (propiconazole + IPBC 0.25 + 0.12%) were combinations of the treatments studied. The efficacy of the treatment systems varied, but the wood material also affected the ability of the paint systems to resist mould growth on the paint surface. The kiln-dried yellow surfaces of the pine and spruce sapwood were more susceptible to mould growth than the spruce surface sawn 10 mm below the original kiln-dried surface. On the resawn spruce material, the most effective treatments were free from mould growth after 26 weeks at RH 100%. However, the effect was markedly lower on the kiln-dried surfaces of pine and spruce sapwood. The influence of natural weathering on the mould growth will be a next stage of the study. The study is a part of a project CT94-2463 in the AIR programme of DG XII.
H Viitanen, P Ahola


Enzyme systems of bacterial isolates from ponded logs - Potentials of pectin and/or starch degradation
2000 - IRG/WP 00-10378
This paper deals with the degradation potentials of wood constituents by the bacterial isolates from ponded logs. The potentials to degrade pectin as a constituent of pit-tori as well as starch existing in ray parenchyma cells in the areas of sap- and transition wood with the isolates were examined. The pectinase activity was investigated by means of the degradation degree of a carrot strip used as a single carbon source in a liquid medium. The amylase activity was studied by the colour change on the iodostarch reaction in an agar medium containing soluble starch as a single carbon source. The results suggested that these substrates were degraded sequentially by plural bacterial species that invaded in the logs during ponding.
S Doi, S Ohta


Evaluation of Barrier Wrap Systems after 71 Months of Exposure
2013 - IRG/WP 13-40631
A 71 month study of the performance of booted samples in ground contact was conducted in AWPA hazard zone 4. Data indicated that excellent performance of wrapped systems, even over untreated wood, could be obtained. Instances of decay colonization or termite attack could all be attributed to some breaking of the integrity of the barrier system. Good performance for treatment below ground contact threshold was demonstrated.
H M Barnes, M G Sanders, G B Lindsey, C McIntyre


Comparative performance of several ammoniacal copper preservative systems
1997 - IRG/WP 97-30151
The efficacy of several ammoniacal copper-based wood preservative systems was evaluated in this study. The selection of potential co-biocides was based on the results of an agar plate test. Following this, the most promising systems were evaluated in a standard field stake test. Good correlation was found between the agar plate and field stake test results. Of the preservative systems tested, copper/tribromophenol, copper/naphthenic acid, copper/DDAC, and copper/propiconizole were found to be superior against copper tolerant fungi in comparison to the other systems tested after three years of field ground-contact exposure. The performance of copper/benzoic acid was mediocre. Copper/citric acid was ineffective against copper-tolerant fungi, with its performance being no better than copper alone.
D D Nicholas, T Schultz


Evaluating the performance of preservative/water repellent emulsion systems
1997 - IRG/WP 97-20127
Water repellent emulsions are being combined with wood preservatives to improve the weathering properties of treated wood in service. Unfortunately, few standard procedures are available to objectively compare the performance of these systems and as a result quality issues are almost completely neglected. The value of swellometer tests, water immersion tests and accelerated weathering regimes in the understanding of water repellent performance is discussed. This paper represents a step towards the development of water repellent standards which will serve to protect both the interests of the consumer and the wood treating industry.
K J Archer, F Cui


The environment and the timber preservation in the Benelux countries
1990 - IRG/WP 3580
The environment has become a major issue in all industries. To focus on the timber preservation industry an analysis is made of the production chain. Suggestions are made for diminishing or excluding emissions of agents of pollution. After a review of the legislation in Holland, some important statements are made on the production process, the products involved and the waste materials. Finally raw materials and energy requirements are discussed. All stages of the product chain should take place in professional business units and under controlled circumstances. The innovations in timber preservation shall be based on existing products, which are very well known, such as CCA and creosote. A controlled and accelerated fixation process should be executed systematically. The preservatives have to be examined on their fixation properties. The industry has to take the initiative for guarantee systems on quality and certification.
C De Mey, R Leegwater


Limiting Conditions for Decay in Wood Systems
2002 - IRG/WP 02-10421
Hygrothermal models can predict temperature and moisture conditions in wall components subjected to real weather data, but specific data and a fundamental understanding of how temperature and wood moisture content dictate the progression of decay under these conditions is required for modellers to predict consequences of decay on building performance. It is well understood that wood will decay above 30% moisture content and will not decay below 20% moisture content. Moisture contents between 20% and 30% represent a grey area. This paper describes cooperative work underway at our two Institutes to define limiting conditions of humidity/moisture and temperature that allow the initiation and progression of decay to diminish the structural performance of wood and wood composites as used in North American light-framed construction. Some preliminary results on time to initiation of decay in wood composites and moisture thresholds for wood materials under steady state environmental conditions are presented. Such a fundamental understanding of the limiting thresholds and eventual rates of decay above those thresholds is mandatory before legitimate models can be developed to predict the expected or residual serviceability of new or old building materials, respectively.
P I Morris, J E Winandy


A novel solvent penetration assessment technique for wood preservativation treatments using waterborne systems
1990 - IRG/WP 2346
Solvent and hence solute (a.i.) penetration during any wood preservation treatment cycle and the flow pathways taken by the solvent in the wood are crucial elements in determining the adequacy of any treatment. Inadequate solvent penetration into specimens or an inappropriate tissue throughflow pattern during impregnation will markedly affect the distribution pattern achieved by many non-diffusible preservative systems. There is to date no direct method of determining the pathways liquid solvents take during their penetration into wood. Currently used methods, such as directional gas permeability measurements are indirect and only provide indications of the relative potential for certain pathways in the wood to be used during liquid impregnation of wood. The following work describes the development and experimental trial of a technique using cryogenic electron microscopy for the direct visual determination of water penetration into samples of Pinus patula and its potential for use in Eucalyptus grandis.
A J Pendlebury, J Coetzee, E Sorfa, A Botha


Durability of surface coating systems. Mycologg - an accelerated mycological test.
2004 - IRG/WP 04-20301
Field testing and natural aging/degradation of test sample, e.g. coated wooden surfaces is a slow process. Accelerated tests focus on mechanical properties, water uptake or sometimes stain fungi. Artificially weathered coated panels are not easily compared with naturally aged panels, and show the importance of involving the biological component among the degrading facors. It is a need for accelerated tests and especially tests that concider the interaction between the property of water uptake, weathering and biological factors. The Mycologg can combine artificial weathering, monitoring of moisture uptake and fungal growth.
L Ross Gobakken, J Mattsson, B Jacobsen, F G Evans


Blue stain in timber in service. Results of further IRG collaborative tests to compare different artificial weathering systems
1981 - IRG/WP 2146
The previous work described in Document No IRG/WP/286 examined 3 preservatives (1% phenyl mercury succinate - PMS, 5% pentachlorophenol - PCP and 1.5% Preventol A4 - PA4) subjected to 5 different artificial weathering systems (BAM Xenotest, Cuprinol Marr, EMPA Xenotest, Gori Atlas and PRL Marr) and after natural weathering at 5 sites (BAM, Cuprinol, EMPA, Gori and PRL). Results showed good correlation between natural weathering and 500 hours in the Marr and Atlas equipments. Natural weathering gave somewhat variable results for PCP and PMS; BAM and EMPA were the most severe and the Cuprinol site least severe. Members of the ad-hoc Group decided during discussions at the IRG meetines in Peebles in 1978, that further work was desirable so that an extended range of fungicides and of weathering equipment could be examined. The 11 participants who agreed to co-operate in various phases of the new work were: BAM (Berlin), Cuprinol (UK), EMPA (Switzerland), Gori (Denmark), Hicksons (UK), Imperial College (UK), Penarth (UK), PRL (UK), Protim (UK), Sadolins (Denmark) and Technological Institute (Denmark).
A F Bravery, D J Dickinson


Blue stain in service on wood surface coatings. Part 1: The nutritional requirements of Aureobasidium pullulans
1992 - IRG/WP 92-1556
The nutritional requirements of Aureobasidium pullulans was examined with regard to nutrient sources that are potentially available in fresh and weathered wood. The study was designed to determine how far wood cell wall components need to be broken down during weathering before they provide a useful nutrient source for Aureobasidium pullulans. Various carbon sources were tested, with eight different isolates of Aureobasidium pullulans. It was found that the organism could utilise the simple sugars well, but not the oligosaccharides. The organism was also able to utilise well several lignin precursor compounds.
P R Sharpe, D J Dickinson


Multicomponent biocide systems protect wood from decay fungi, mold fungi, and termites for interior applications
2004 - IRG/WP 04-30333
Concerns about indoor air quality due to mold growth have increased dramatically in the United States. In the absence of proper moisture management, fungicides need to be developed for indoor use to control mold establishment. An ideal fungicide for prevention of indoor mold growth on wood-based materials needs to specifically prevent spore germination and provide long-term protection under conditions of high humidity. Fungicides intended for indoor use must be nontoxic, nonvolatile, odorless, and hypoallergenic. Multicomponent systems were tested in AWPA soil block tests for inhibition of brown-rot and white-rot fungi, and ASTM standard tests for inhibition of mold fungi and termites. Multicomponent biocide systems combining a borate-base supplemented with voriconazole or thiabendazole, and either thujaplicin, or ethanolamine performed well against two brown-rot fungi, Postia placenta, and Gloeophyllum trabeum, the white-rot fungus, Coriolus versicolor, three mold fungi, Aspergillus niger, Penicillium chrysogenum, and Trichoderma viride, and the subterranean termite, Reticulotermes flavipes (Kollar). We conclude that a multicomponent biocide system containing Bor-A+ supplemented with azoles and either ethanolamine or thujaplicin can protect wood from decay fungi, mold fungi, and termites for interior applications.
C A Clausen,V W Yang


Efficacy of copper:propiconazole and copper:citrate systems in ground contact exposure at a site with copper tolerant fungi
2003 - IRG/WP 03-30305
Southern yellow pine (SYP) sapwood field stakes were treated with copper alone (ammoniacal copper carbonate, ACC) at four levels, or three levels of copper (1.6, 3.2, or 6.4 kgm-3, as CuO), air-dried, then re-treated with propiconazole in a light organic solvent at 0.07, 0.3, or 0.7 kgm-3 retentions. In a separate study, SYP field stakes were treated with three levels of ACC to give 6.7, 13.4 or 29 kgm-3 retentions, or the same ACC levels plus citric acid at 38% of the CuO level. These ground-contact stakes were installed at a test plot which has copper tolerant fungi, and inspected regularly for fungal and termite degradation. At the most recent inspection, the copper azole stakes had been exposed for 118 months and the copper citrate stakes for 100 months. For the copper azole stakes, copper alone was only effective at the highest copper retention (10 kgm-3, CuO basis). In contrast, the copper azole-treated stakes were adequately protected with 1.6 kgm-3 CuO and the highest (0.7 kgm-3) level of propiconazole, or 3.2 kgm-3 CuO and 0.3 or 0.7 kgm-3 propiconazole, or 6.4 kgm-3 CuO and 0.07 kgm-3 (or greater) propiconazole. For the copper citrate stakes, stakes treated with copper alone performed slightly better at all three retentions than the copper:citrate-treated stakes. We conclude that the co-addition of propiconazole provides increased protection against copper tolerant fungi and other wood-destroying organisms, with increased azole levels necessary as the copper retention is lowered. In contrast, the co-addition of citric acid did not increase the efficacy of copper.
D D Nicholas, T Schultz


Industrial fixation systems: key factors, limitations and optimisation through the use of computer simulation modelling. Discussion paper
1994 - IRG/WP 94-40026
This paper briefly describes four fixation operative in the Netherlands, namely: circulating and non-circulating steam fixation cylinders, steam fixation chambers and controlled climate rooms. The general limitations of industrial practice are reviewed against the background of established fixation theory. The controlling variables, both material and process-related, for fixation processing are specified. The capabilities of computer simulation modelling to highlight and provide solutions to these problems is illustrated.
A J Pendlebury, M Riepen, M J Boonstra, W Gard


Standard and accelerated testing of boron-additive wood protection systems
2005 - IRG/WP 05-30381
The main objective of this research was to determine the effectiveness of boron-additive protection systems for above ground applications by means of field testing. The two field test procedures used are based on the L-joint test described in the European standard EN 330. For the first set up the boron treated timber was coated in accordance with the standard EN 330 system. The second set up is based on an accelerated test simulating uncoated applications and includes an additional moistening of the jointing area. After three years of aboveground exposure, boron preservatives are still providing an adequate protection to coated L-joint specimens. Based on the results obtained it can be concluded that boron-based compounds still provide good protection after three years of natural weathering when protected by a three-coat finish. Similar uncoated L-joints treated the same way show rapid deterioration under the accelerated exposure conditions applied. The mass loss data revealed a significant level of decay for the uncoated specimens even when treated with boron-additive formulations. This is attributed to the high leaching hazard related to the accelerated exposure method used. The latter proves to be too aggressive for all tested boron-based preservatives when unprotected by surface coatings. A treatment with 1 % CCA under the same conditions was still performing adequately after 3 years even under accelerated L-joint exposure of uncoated test samples.
A Mohareb, J Van Acker, M Stevens


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