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Possibility of use of wood species per class of biological risks. Attempt to determine criteria based on Pr EN 350-1/2/3
1992 - IRG/WP 92-2409
M Rayzal

Biological performance of gypsum products containing borates
2000 - IRG/WP 00-30237
At suitable retentions borates have biostatic properties enabling them to be used for biodeterioration control in wood. They provide protection against decay fungi, mould, and termites, which are known to also attack gypsum products. Currently, many gypsum products contain added borates, which are used to improve physical and processing characteristics. Work examining the effect of borates at controlling biological attack in gypsum products is presented in this paper. Gypsum or gypsum board with different borate loadings was tested for its performance against dry rot, mould, and subterranean termites in order to see if current commercial levels of borates used in gypsum products would also render them resistant to these common types of biodeterioration. It was confirmed that the presence of borates significantly decreases the amount of biological attack found in gypsum products. From the results obtained it can be concluded that the addition of borates to gypsum products provides more than simple mechanical and processing improvements. For complete biodeterioration control however, especially against mould, higher retentions should be considered. This knowledge could have great significance in the near future, with moves to require termite resistant construction materials (including gypsum board) in some areas and the rising concern of illnesses associated with 'sick building syndrome' caused by in-house mould growth.
J L Fogel, J D Lloyd

European standardization for wood preservation
1990 - IRG/WP 2359
G Castan

Biological agents of timber degradation in Portugal. Marine borers
1991 - IRG/WP 4171
A brief report of the studies carried out in Portugal on marine borers is presented. The marine borers found in the portuguese coast are refered as well as the wood species where those organisms were identified. Emphasis is given to a study carried out from 1960 to 1975 at the Tagus estuary in Lisbon with the purpose, among others, of establishing the natural durability of different timbers.
J S Machado, L Nunes

The leachability, biological resistance, and mechanical properties of wood (Pinus sylvestris L.) treated with CCA and CCB preservatives
1999 - IRG/WP 99-30207
Scots pine (Pinus sylvestris L.) specimens treated with CCA and CCB preservative solutions (1.0%) were subjected to several fixation processes and leached elements from the specimens were determined. In addition, the specimens exposed to different fixation temperatures were subjected to soil-block test using two brown-rot fungi and one white-rot fungus in order to investigate the effects of fixation temperature on the biological performance of treated wood. The effects of preservative treatment and subsequent redrying at temperatures of 20°C and 70°C on the bending strength, MOE (modulus of elasticity), and impact bending strength of small, clear specimens treated with CCA. At 20°C and high moisture contents and also with steaming, leaching rate of the components decreased. In addition, the specimens treated with CCB and conditioned at 20°C/32-100% RH (relative humidity) conditions, the percent elements leached were less than those in the specimens treated with CCA and also the rate of fixation increased significantly in the CCB-treated specimens. In the CCA treatments, the weight losses by Gloeophyllum trabeum and Postia placenta fungi were more than 5% with the fixation methods such as ovendrying at 120°C, and steaming at 80°C for 60 and 90 minutes while with the other fixation methods, the weight losses obtained were less than 5%. At redrying temperatures of 20 and 70°C, CCA had no significant negative effect on the bending strength, MOE, and impact bending strength properties of the specimens.
S N Kartal

Decay resistance of resin treated wood
1999 - IRG/WP 99-30206
Selected natural resin systems were evaluated for their potential as wood protecting agents according to standard test procedures. As indicated by the European standard EN 599 both a Basidiomycete test according to EN 113 and a ENV 807 soil bed test were carried out. Six resin treatments were tested using 3 concentration or treatment levels. Using the biocidal activity criteria as usually applied for wood preservatives it became obvious that resin treatments do not comply to the standard requirements. None of the resin treatments tested allowed the establishment of toxic limits when all Basidiomycete fungi were considered. Four resin systems showed a clear impact of retention. The functional relationship of the percentage mass loss to the resin retention was examined. Based on this function the retention levels corresponding with specific mass loss levels were calculated for each fungus. Treatment levels are proposed taking into account the envisaged utilisation under European hazard class 3 (EN 335) and the mass loss criteria for wood species belonging to natural durability class 3.
J Van Acker, A J Nurmi, S M Gray, H Militz, C Hill, H Kokko, A O Rapp

Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper tolerant brown rot organism in leaching environments.
S M Gray, D J Dickinson

The effect of treatment temperature on the biological performance of CCA treated wood
1990 - IRG/WP 3624
Birch and Scots pine sapwood blocks were treated with several concentrations of CCA at three different temperatures: 5, 20 and 35°C. The treated wood was maintained at the appropriate temperature for the fixation period. Leached and unleached samples were then exposed in a soft rot monoculture test using Chaetomium globosum and a brown rot monoculture test using Coniophora puteana. The treatment temperature had little effect on the performance against brown rot but the performance of birch against the soft rot improved as the treatment temperature increased particularly after leaching.
S M Gray

Assessing the performance of wood preservatives from biological tests - the European approach
1994 - IRG/WP 94-20040
The impetus for the European Standardisation Committee to undertake the development of a performance standard for characterising the effectiveness of wood preservatives from biological tests, lies in the Construction Products Directive. This is effectively the European Community law which provides the basis for Construction Products to be traded across all member states without technical or regulatory barriers and without having to undergo further testing or re-certification. The performance standard covering wood preservatives is EN 599 and it defines the performance which preservative products will be required to achieve in specific laboratory and field tests, in order to be accepted and marketed as suitable for particular conditions of use. Five hazard classes of use are defined in another standard (EN 355-1) and EN 599 lists the specific biological tests required for each hazard class, the maximum amount of the product that can be applied in each test, the need for pre-leaching or pre-ageing and the rationale for deriving a value (the biological reference value) for the minimum amount of product deemed effective in each test. The highest biological reference value determined from all the tests is defined as the critical value and it is this value which is carried forward to the standard covering treated wood (EN 351) to provide the basis for defining the minimum amount of product required for effectiveness within treated commodities. EN 599 lists the minimum testing requirements for each hazard class together with optional additional tests to provide efficacy assessment against a wider range of target pests or to increase confidence in the critical value by incorporating data from longer-term field tests. The standard also describes the requirements for marking and labelling preservative products to describe their suitability for specific uses. Work on EN 599 commenced in 1988 and its development has required negotiated agreement between the 18 member states of the CEN/CENELEC region with 12 different working languages and 3 different official languages for documentation. EN 599 is now at the final stage of submission to vote and the decision on its adoption and implementation will be announced before the end of 1994.
A F Bravery

Copper linoleate: A new low toxcity wide spectrum, heavy duty wood preservative
1995 - IRG/WP 95-30082
Copper linoleate, a "fixed" copper soap has been developed and evaluated in South Africa over a 30-year period. The initial product, an organic solvent based preservative has been tested in pine poles against termites and fungi. Results indiate that the product has performed well against existing heavy duty wood preservatives such as CCA and creosote in long term field trials (30 years). The paper describes the basic formulation of copper linoleate and the reaction and possible fixation mechanisms of copper linoleate with wood lignin. The paper moves on to describe further work on an emulsifiable version of copper linoleate for use as a water borne wood preservative. The performance of this product is evaluated in accelerated trials to obtain comparative performance data. The emulsion-based product addresses a need for a low-toxicity, waterborne, heavy duty wood preservative. The paper also considers some of the physical properties of the product and outines the remaining barriers for its industrial commercialisation.
D Conradie, P Turner, W E Conradie, A J Pendlebury, T Pizzi

Effect of nutrient regimes, temperature, pH, and wood sterilization method on performance of selected bioprotectants against wood staining fungi
1992 - IRG/WP 92-1551
The effect of nutrient regimes, incubation temperature, media pH, and wood sterilization method on performance of four potential bioprotectants (Pseudomonas putida, Pseudomonas cepacia, Bacillus subtilis, and Trichoderma harzianum) against wood staining fungi were evaluated using small ponderosa pine samples over a four week period. Incubation at 32°C resulted in slight increases in the degree of fungal stain, but the results were not consistent across treatment groups or bioprotectant species. Bioprotectant performance was altered through the use of different media, but, once again, the results were not consistent across all treatments for a given media. The pH of the media had a substantial effect on bioprotectant performance, with acidic conditions producing the poorest performance of bacterial bioprotectants and alkaline conditions reducing the protective effects of Trichoderma harzianum. The method of wood sterilization produced alterations in both the degree of staining and the composition of the microbial flora of the wood. Unsterile samples were stained to a greater degree than either autoclaved or irradiated specimens and the degree of bioprotection was generally lower. Delays in the interval between bioprotectant application and inoculation with wood staining fungi generally reduced the effectiveness of the bioprotectant, suggesting that bioprotection declined with incubation period. The results illustrate the complexity of developing bioprotectants which can effectively compete under the array of conditions common to freshly sawn lumber and suggest that considerable additional research will be necessary to more fully understand the conditions which assure successful protection.
J J Morrell, C M Secton

Variation in biological performance of CCA caised by preservative application method
1996 - IRG/WP 96-40072
A series of laboratory studies to investigate the influence of treatment application method on CCA performance in Cosican pine has been completed. Biological decay tests, such as serial exposures, were used to induce decay in wood at preservative retentions of up to 10 kg/m³ CCA salts. Significant differences in performance of the preservative against either brown, white or soft rot decay fungi were found depending upon the preservative application method used. The full-cell process gave the greatest level of CCA performance against Coniophora puteana whereas the Lowry empty-cell process gave the best performance against Coriolus versicolor and soft rot fungi. Pre-treatment steaming caused a general reduction in preservative efficacy. Analysis of the treated wood using FT-IR spectroscopy and electron microscopy with EDS for preservative micro-distribution indicated modification of the wood cell wall by steaming and differential distribution of copper depending on preservative application method. A hypothesis is proposed to account for the observed differences in preservative performance with treatment method.
P R Newman, R J Murphy

Accelerating effects of the field biological attacks in a weather controled soil bed room
1997 - IRG/WP 97-20118
For the purpose of the accelerating the field evaluation of the material service life, a weather controlled soil bed room were designed. The room was controlled 30°C, 75%R.H. In this room, water was sprayed 15 minutes a day. The workers and soldiers of termite, Reticulitermes speratus, can be penetrated. The comparison results of preservative brushing coated treated stakes between field ones and ones in this room were reported. The results obtained were shown in Table 3. This room can be accelerated about two times than the field test site at Tsukuba in Japan.
K Suzuki, I Momohara, T Nishimura

Biological Performance of micronized copper wood preservative formulations in field and laboratory tests
2008 - IRG/WP 08-30488
Micronized Copper wood preservative formulations with different co-biocides were exposed to brown rot fungi in an 8-week AWPA E10 soil block decay test and two AWPA E7 ground-contact decay tests in Hawaii. The micronized copper formulations performed well against decay at or above the AWPA UC3 and UC4 retentions stipulated by the ICC-ES. Micronized copper preservatives performed comparably to a conventional ACQ reference preservative. In the soil block decay test, micronized copper azole (MCA) performed similarly to ACQ-D using three brown rot decay fungi. In a 40-month ground contact decay test, southern pine stakes treated with MCA, micronized copper quat (MCQ), and ACQ-D at or above the UC4A retentions performed similarly and each rated greater than 9.0 against decay.
G M Larkin, J Zhang, D L Richter, R J Ziobro, P E Laks

Biological Performance of Boron-based Chemicals Treated Wood Composites
2009 - IRG/WP 09-40464
In this study, the biological performance of wood-based composites panels treated with boron containing chemicals against to a fungus was determined. Boric acid, borax, zinc borate and agricultural borate (Tarım-bor™), developed and patented by National Boron Research Institute, were mixed with wood chips or fibers and then particleboard, medium strand board and middle density fiberboard were produced. The decay tests of these wood composites were done according to the soil-block test. Among the boron compounds, zinc borate demonstrated better resistance against to C. puteana fungus than other boron compounds used in this study. According to the durability classification, MDF was better than particleboard and MSB.
Ü C Yıldız, H Kalaycıoğlu, S Yıldız, A Temiz, E Tomak Dizman, A Çavdar Dönmez

The biological durability approach for wood product performance and service life prediction
2010 - IRG/WP 10-20457
The performance of wood-based products under conditions that enable biodegradation are of concern to all who envisage sustainable use of forest based products. This concern is also the basis of classification of wood species on the basis of their biological durability. Engineers are looking for options to transfer such classification into practical service life values for constructions and related service life prediction, but they should be able to process also the variability and reliability of the intrinsic biological durability of the material. Hence this paper mainly focuses on an improved statistical approach of biological durability of wood related to outdoor uses in out of ground contact situations. Starting with Weibull distribution functions of mass loss data obtained from worst case laboratory Basidiomycetes testing some parameters are proposed. Clearly the median mass loss value recorded for the most degrading test fungus is a suitable factor to classify a sample of wood with regard to the resistance to decay, but other quantiles like those for 10% or 90% of the observations are useful to indicate variability in service life that can be expected. Furthermore the use of percentages of the wood material that can be attributed to different durability classes allows a probabilistic approach and might help engineers to develop a better technology for assessing wood product performance and use such factors as service life indicators. For a wide range of wood species statistical factors are presented which could replace current simple durability class approach and which might help to differentiate from the common in ground contact classification on durability. Since a lot of valuable wood species are mainly used for use class 3 applications like window joinery, cladding, decking and garden furniture it is of interest to obtain reliable data for calculating service life of such wood-based products anyhow.
J Van Acker, J Van den Bulcke, L De Boever

Biological performance of wood treated with tar-oil recovered during slow pyrolysis of macadamia nut shells
2010 - IRG/WP 10-30523
This study evaluated decay and termite resistance of wood treated with tar oil obtained from a commercial pyrolysis process of macadamia nut shells. Vacuum-treated pine wood specimens were subjected to various brown and white rot fungi based on the soil-block test method specified by the American Wood Protection Association (AWPA) after leaching process. Treated specimens were also subjected to the subterranean termite attack according to Japanese Industrial Standards (JIS) for 3 weeks. In the study, growth inhibition of selected fungi with the tar oil was tested in vitro. Treated wood specimens at 460 kg/m3 retention level showed good protection against all fungi tested. Mass losses in leached specimens were less than those observed in unleached specimens. Similar results were seen when the specimens were subjected to termite attack. Inhibition tests showed that higher concentrations of the tar oil are critical for inhibition of the brown rot fungi compared to the concentrations required to impede the white rot and sap staining fungi tested.
S Nami Kartal, E Terzi, C Kose, J Hofmeyr, Y Imamura

Impact of wood species on the performance of exterior wood coatings
2010 - IRG/WP 10-40519
To prolong the service life of a wooden construction the protective function of a coating is of utmost importance. The chemical composition as well as the wood-coating interface affects the performance of this protective layer and obviously wood species have an impact too. This paper discusses the influence of wood species on the overall coating performance. Therefore, a range of opaque waterborne acrylic coatings applied on industrially finished window frames made of frequently used commercial hardwood and softwood species were tested. Both, artificial and natural weathering, were considered for the durability assessment. Complementary studies on moisture dynamics and fungal growth were included as well. Coatings applied on dense tropical hardwood with large vessels perform fairly well in regard to water related failure, but erosion or weathering phenomena occur early. The opposite is true when examining small or medium porous hardwoods. Coatings applied on softwood substrates performed the worst. Yet, in contrast to hardwood, the performance of softwood based systems under laboratory test conditions is less correlated with outdoor performance.
I De Windt, J Van den Bulcke, J Van Acker

Biological performance of wood- and bamboo-polypropylene composites: Effects of particle content, particle size and Zn borate
2012 - IRG/WP 12-40577
Particle content and size of wood material in wood plastic composites (WPCs) can affect efficacy of WPCs against fungi and termites. This study evaluated fungal and termite resistance of WPCs manufactured by using two different levels of particle content (50 and 70%) and three different particle sizes (30, 60, and 100 mesh). In fungal resistance tests, Tyromyces palustris, a standardized test fungus, Schizophyllum commune and Pycnoporus coccineus observed previously on commercial WPC products in field tests by various researchers were employed. Termite resistance tests were performed in laboratory conditions using the subterranean termites, Coptotermes formosanus. Mold growth on the WPCs was evaluated in a test period of 4 weeks. In general, WPC specimens containing higher particle content and smaller particle size resulted in increased mass losses in decay resistance tests. As particle content increased, mass losses in the specimens in termite resistance tests increased; however, decreased particle size caused slightly decreased mass losses. The composite specimens along with Zn borate treated specimens were completely colonized by the fungi in a short period of 4 weeks.
S N Kartal, S Aysal, E Terzi, T Yoshimura, K Tsunoda

Improvement of the biological performance and dimensional stability of two tropical woods by thermal modification
2012 - IRG/WP 12-40605
Pink cedar wood and rubberwood were thermally modified at 230°C in air for 4 h or for 8 h, and then subjected to bending, compression and hardness tests to evaluate the effect of the treatment on these mechanical properties. The biological performance of the modified wood was also determined, according to EN113, and the dimensional stability measured by means of the anti-swelling efficiency. The thermal modification afforded increased decay resistance and improved the dimensional stability of these tropical woods, at the expense of significant reductions in the Modulus of Rupture and the Work at Maximum Load in the bending test. The reduction in bending strength and in resilience was not significant at the limit of proportionality though; the modified material is hence deemed as suitable for non-structural applications where the occurrence of sudden loads shall not lead ultimately to human harm. Color changes resulted in aesthetic enhancements on these two wood species, particularly so in pink cedar wood. These color changes were readily exploited for the multivariate prediction of all properties studied in this work, including the decay resistance of thermally-modified wood.
M M González-Peña

Biological Performance of Triadimefon in combination with Tebuconazole in laboratory and field tests
2015 - IRG/WP 30668
The usage of Triazole-combinations for wood preservatives is common practice in several countries. Especially the combination of Tebuconazole and Propiconazole is preferred for this application due to its broad spectrum of efficacy against wood destroying fungi. 1-(4-Chlorphenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-butanon, also known as Triadimefon provides a good efficacy against the wood destroying fungi species Poria placenta and Coriolus versicolor and is therefore a possible active ingredient to be combined with Triazoles already in use, which are showing a moderate or lower efficacy against other important fungi species like Coniophora puteana and Gloeophyllum trabeum. This paper summarizes laboratory tests done with the active ingredients Triadimefon and Tebuconazole, as single actives and also in combination with each other, as well as the results of subsequent field trials in USA, Denmark and New Zealand.
P Meckler, T Jaetsch

Incorporation of raw boron minerals to protect particleboard against decay and mold fungi, termites and insects
2016 - IRG/WP 16-40729
This paper evaluated the biological performance of particleboards incorporated with the raw boron minerals ulexite and colemanite against decay, mold fungi, termites and insect larvae in comparison with that of particleboards with zinc borate, or boric acid plus a borax mixture. The results showed that ulexite and colemanite were highly effective against the decay fungi and termite attack in laboratory conditions. However, the boron minerals tested were not as effective as zinc borate or the boric acid/borax mixture in preventing mold growth. In general, the boric acid/borax mixture combination was more effective against Anobium larvae than the other compounds. Less boron release was seen in the specimens containing zinc borate and colemanite than in those containing ulexite or the boric acid/borax mixture. Further mechanical and physical tests (water absorption, swelling etc.) will be needed to evaluate the particleboard properties and the compatibility of the boron minerals with glue and manufacturing conditions.
S N Kartal, E Terzi, P Gerardin, C M Ibanez, T Yoshimura

Moisture behaviour and biological durability of high performance flax fibre reinforced composites
2017 - IRG/WP 17-40803
For natural fibre composites in structural and load bearing applications long reinforcing fibres are required. Therefore, much research is performed on flax fibre reinforced composites to optimize them for high performance use. In most cases such research focuses on the mechanical properties, yet the assessment of moisture behaviour, dimensional stability and biological durability is an important aspect as well concerning in-service performance. In this study we assessed the properties of flax composites made with maleic anhydride grafted polypropylene (MAPP) or epoxy and reinforced with mat, unidirectional, cross-ply unidirectional, quasi unidirectional, plain weave or twill weave reinforcements. Testing water immersion and fungal resistance with Coniophora puteana and Trametes versicolor showed that epoxy composites performed better than MAPP composites. Furthermore less water absorption and lower biological degradation was observed when reinforcement was more structured. The type of resin, manufacturing process and reinforcement type influences the impregnation quality and porosity of the composites. It is possible that the manufacturing process changes the fibre chemistry in a way that fungi such as C. puteana encounters difficulties degrading them. Further research is needed to explain such behaviour.
N Defoirdt, J Van den Bulcke, F Bensadoun, J Ivens, I Verpoest, J Van Acker

Mechanical, Physical and Biological Properties of Sandwich Biocomposites Panels manufactured from Food Packaging Waste
2017 - IRG/WP 17-40791
Recently, recycling of Tetra Pak® packaging material has attracted many attention, particularly in composite industries. In this work, novel biocomposites sandwich structures were manufactured using TetraPak waste materials as core component and various kind of natural and artificial woven fabrics as skin elements. Mechanical, physical and biological performances of the developed composite panels were evaluated. The results showed that using a layer of woven fabric made of either Jute (J) or Glass (G), has a significant effect on MOR of TetraPak panels. MOR value of the stand-alone TetraPak panels (TP) [No-Skin] was 9.75 MPa while MOR values of J-TP-J and G-TP-G are 20.31 MPa and 22.67 MPa, respectively. Distinct observations have been remarked concerning the physical performance of the developed biocomposites. In general, significant improvements in water absorption and dimension stability were recorded with all TetraPak based specimens compared with the control particleboard specimens. After 12 weeks of fungal exposure, mass losses in TetraPak based composite specimens were considerably lower. However, TetraPak panels overlaid with fiberglass fabrics showed the highest decay resistance against test white and brown rot fungi. The results of termite screening tests showed that all reinforced TetraPak samples were gained significant enhancements against termite attack compared with the solid wood reference specimens. Therefore, the resulting composites seem to possess a great potential to replace wood based products in broad range of applications.
A S O Mohareb, A H Hassanin, K Candelier, M F Thévenon, A Kilic, Z Candan

Durability of acetylated Radiata pine: Laboratory tests and performance in practice
2020 - IRG/WP 20-40899
Wood acetylation is an established process to enhance biological durability and dimensional stability of lower valuable wood species without the use of biocides. Acetylated Radiata pine (ACCOYA® wood) has been on the market for more than 10 years now, starting in 2007. Numerous lab tests have confirmed the high durability of acetylated Radiata pine. Here, additional data with four Radiata pine assortments of different origin and quality are shown. All tested variants achieved durability class 1 in both the basidiomycete test and soft rot test according to EN 350. Thereby, no significant differences of the durability characteristics between and within the assortments were found, even though different initial wood qualities were used. Since acetylated wood has not been on the market for that long, less is known about the long-term performance in practice although several long-term field tests are running. As a result of an inspection and evaluation of seven Accoya® constructions exposed outdoors in the Netherlands and Germany over a period of 1 to 10 years, the high dimensional stability and durability against wood-destroying fungi could be confirmed. From the perspective of the authors of this study, the results of the investigation confirm the results of standard lab tests and practical experiences, where the durability class 1 "very durable" (EN 350) was determined.
K Jacobs, W Scheiding, B Weiß

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