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Biological degradation of acetylated wood after 18 years in ground contact and 10 years in marine water
2010 - IRG/WP 10-40522
This paper addresses the resistance to biological degradation of acetylated wood. Firstly, it presents results from an EN 252 test after 18 years’ exposure. The test is still running in Nordic NWPC test fields, Simlångsdalen in Sweden and Viikki in Finland. Results from this test were presented after 5 years’ exposure ( IRG/WP 97-30139), and showed that the resistance of acetylated wood with an acetyl content of about 20% was in the same range as that of wood treated to the high retention of the reference CCA preservatives. At acetylation levels above 20%, none of the samples was rated higher than rating 1, either in Simlångsdalen or in Viikki. After 12 years’ exposure the average index of decay was 51 in Simlångsdalen and 45 in Viikki for the medium level of acetylation (average acetyl content: 19,8%), compared to the high retention level of the NWPC Standard CCA preservative, where the index of decay was 41 and 31, respectively. Making the same comparison after 18 years’ exposure in Simlångsdalen, the index of decay was 56 for the high retention level of the NWPC Standard preservative. For the acetylated test stakes, the corresponding figures were 65 for the medium level and 60 for the high acetylation level (average acetyl content 22,0%). This implicates that in order to be comparable with the CCA preservative for 18 years, an acetyl content of above 22% is needed. This is true when exposed in a brown rot soil. However, it should be pointed out that in the test field in Finland the stakes with the high level of acetylation performed extremely well, confirmed by an index of decay of 12,5 compared to the high retention of the NWPC reference CCA preservative where an index of decay of 60 was obtained. Secondly, acetylated wood (acetyl content 22%) has also been evaluated after 10 years’ marine exposure at Kristineberg on the Swedish west coast. The test is still running and is conducted according to EN 275 (marine borer resistance). The test was started in 1999 and the X-ray rating now shows a moderate attack by marine borers, whereas the untreated controls failed after only one year. If the acetylation (acetyl content 21%) is followed by a post treatment with melamine resin (weight gain 19%) no attack could be observed after ten years.
P Larsson Brelid, M Westin

Performance of untreated wood and wood impregnated with copper-ethanolamine based preservative solutions in Northern Adriatic Sea
2013 - IRG/WP 13-30623
Sea water applications of wood are among the most challenging ones. Impregnated wood is exposed to leaching and to variety of marine borers, Limnoria sp. and Teredo sp. being the most important. In the present research, durability of pine wood impregnated with copper-amine based preservative solution (Silvanolin) of different concentrations, exposed to the sea water, was investigated according to the EN 275 standard. Performance of Silvanolin treated wood was compared to performance of naturally durable wood (Quercus sp., Castanea sativa, Larix decidua). After 10 months, 18 months and 32 months of exposure, the samples were isolated and assessed. From the presented results it can be clearly seen, that durable wood species were completely degraded after 10 months of exposure. On the other hand, it is evident that Silvanolin prolongs the service life of exposed wood in the sea. The specimens impregnated with the lowest concentration of the preservative solution (cCu = 0.31 %) were only slightly decayed. At specimens, impregnated with higher concentrations of copper (cCu > 0.31 %) almost no defects were observed as a results of exposure to marine borers.
M Humar, M Petrič, J Adamek, B Lesar

Performance of some wood modification treatments against marine borers
2014 - IRG/WP 14-40668
Since some years, new treatment technology to protect wood against wood destroying fungi is introduced. Limited knowledge on their resistance to water organisms is available. Therefore, the resistance of chemically modified wood was assessed in a field test according to the European Standard EN 275 over a period of 3 resp. 5 years at sites in the North Sea and the Baltic Sea. Scots pine (Pinus sylvestris) sapwood was treated with DMDHEU (dimethylol-dihydroxy-ethylen-urea), MMF (methylated-methylol-melamine), TEOS (tetra-ethoxy-silane) and PF (Phenol-formaldehyde). In addition, acetylated and untreated Radiata pine (Pinus radiata) was tested. The content of the modification agent in the exposed samples was determined annually in order to determine the stability of the treatment during the exposure in seawater against leaching during the first three years of exposure. The chemical contents stayed stable, indicating that leaching of modification chemicals did not occur. The common shipworm (Teredo navalis) was the only wood boring organism found at the two test sites. Most controls were destroyed within one year. Modified specimens showed varying severeness of attack by T. navalis, depending on the modification method. The resistance of resin treated wood seems to depend not only on the type and concentration of resin, but also on process parameters.
A Klüppel, C Mai, H Militz, S Cragg

Testing of the resistance of acetylated wood against marine borers at three Italian sites
2017 - IRG/WP 17-30719
The aim of this research is the determination of resistance of acetylated wood against marine biodeterioration in use class 5 (EN 335) in temperate sea waters. The resistance of acetylated Pinus radiata (radiate pine) in solid and MDF form is compared with that of the untreated radiata pine and other untreated wood of European species such as Fagus sylvatica (European beech) Castanea sativa (chestnut), and Quercus robur (European oak). As reference control, untreated scots pine (Pinus sylvestris) sapwood is used. The field tests were carried out in accordance with EN 275 and started in April 2015. The three Italian exposition sites were Ligurian Sea, Tyrrhenian Sea and Venice Lagoon. Evaluations in 2016 and 2017 showed a greater resistance to marine borers of acetylated wood and MDF specimens compared to the untreated ones, even to durable species such as oak and chestnut. Most of the control samples (untreated scots pine and beech) were completely destroyed.
S Palanti, M Faimali, D Tagliapietra, M Andrenacci, M Anichini, M Sigovini

Resistance against marine borers: About the revision of EN 275 and the attempt for a new laboratory standard for Limnoria
2020 - IRG/WP 20-20669
Wood protection technology in the marine environment has changed over the last decades and will continue to do so. New active ingredients, newer formulations, and novel wood-based materials including physically- and chemically-modified wood, together with increasing concerns over environmental impacts of wood preservatives, urgently demand a major revision of EN 275 “Wood preservatives – Determination of the Protective Effectiveness against Marine Borers”, dated from 1992. This IRG document reports on the technical work in CEN TC 38 regarding the revision of this standard. A Task Group within WG 24 of CEN TC 38 was formed consisting of experts from different field of competence (e.g. wood preservatives industry, wood scientists, marine biologists, archaeologists and cultural heritage conservators). Starting by e-mail correspondence in 2014, and continuing with four physical meetings (Berlin 2x, Florence, Venice) with experts from Germany, Italy, Sweden, and UK were held so far. Significant items for revision in EN 275 were identified as: number of replicates, duration of the test, dimension of specimens, number of test sites, number of reference species, reference material including reference preservative, re-immersion of specimens after non-destructive periodical evaluation for longer periods of time vs higher number of replicates for successive destructive examinations without re-immersion, utilization of X- ray apparatus and specific software to ease evaluation, etc. Furthermore, the task group is working on a standardized lab test for time-saving evaluation of different wood qualities for their potential to resist attack by limnorids. The suitability of this lab test will be determined by round robin tests as soon as safe face-to-face collaboration permits. The outcome will be published as a CEN TR (Technical Report) document, with a view to eventual adoption within the revised standard.
S Palanti, S Cragg, R Plarre

A suggested method to test the toxicity of wood preservatives towards the house longhorn beetle
1977 - IRG/WP 275
This method was developed in the Institute for Wood Technology in Sarajevo, Yugoslavia and is used to get quick information on the toxicity of wood preservatives against house longhorn beetle (Hylotrupes bajulus). The method can be used for superficially treated or deeply impregnated wood blocks, and by using small or normal size test material it can be used as a laboratory or field test, and also for accelerated infestation of test material out of ground contact. The paper is given to the International Research Group on Wood Preservation as a suggested method which could possibly be used as a standard. Only the laboratory test method is described.
N Vidovic

Comité International Permanent pour la Recherche sur la Préservation des Matériaux en Milieu Marin. Information from the Wood Group
1980 - IRG/WP 460
E G B Jones

Insect resistance of preservative treated tropical plywood against Lyctus
1990 - IRG/WP 1453
Seven plywood types composed of tropical wood species, vulnerable to Lyctus, were treated with various commercial water-borne and oil-borne preservatives. A wide range of preservative retentions was obtained by treating boards with dip treatment, steeping, double-vacuum and vacuum-pressure impregnations. Selected samples were subsequently tested for their insect resistance against Lyctus africanus during 6 to 8 months according to European Standard EN 20. All control samples were attacked, except one Obeche plywood exhibiting only 50% attack. Water-borne preservative solutions containing arsenic, boron or fluoride could not prevent attack at common retention levels for interior use e.g. lower than 5 kg/m³. Quaternary ammonium compounds showed no insecticidal efficiency, up to 3 kg/m³. TCMTB at 1.5-1.7 kg/m³ proved to be able to reduce slightly the susceptibility for insect attack. Organic insecticides gave the best results, with nearly no attack for plywood treated with lindane or cypermethrin. In spite of a preservative uptake of 25 to 30 kg/m³, endosulfan only could reduce attack by 50%. Protection by permethrin at 0.1% a.i. required a retention of 28 kg/m³. Besides the fact that variability in wood species and composition of the plywood are leading to different retention levels, variation in penetration and distribution of a.i., and as a consequence to a different insect resistance of the impregnated boards, some poor results were directly related to inadequate insecticidal activity and/or concentration of a.i. in some commercial formulations for Lyctus control.
J Van Acker, M Stevens, M Pallaske

Studies on accelerated ageing procedures with TBTO-treated wood
1985 - IRG/WP 2244
The efficacy of various procedures for accelerated ageing of organotin based wood preservatives in treated wood has been investigated. It was found that leaching of the treated wood samples in water according to the European Standard EN 84 was not satisfactory for organotin based preservatives and is probably also unsuitable even for other types of organic solvent preservatives. Keeping tributyltin oxide (TBTO) treated samples in a heating cabinet at 70°C for five weeks, however, had a considerable effect on the breakdown of TBTO and the subsequent decay test. Therefore, an ageing procedure involving a heating period should be considered for all organic solvent wood preservatives. The investigation also confirmed that elevated temperatures accelerate the degradation of TBTO and that there is a strong correlation between the percentage of TBTO in the wood and its resistance against decay.
J Jermer, M-L Edlund, B Henningsson, W Hintze

Temperature influence on the growing velocity and cellulolytic activities of Poria placenta strains from several locations
1986 - IRG/WP 2263
The differences observed on the FPRL 280 Poria Placenta strain at several Research European Laboratories for determining up the fungicide effectiveness of wood preservative has carry us to do a comparative study about the cellulolytic activity and growth velocity of each of this strains at different temperatures (22, 24 and 28°C). The results show significative differences when the temperature is changed.
A M Navarrete, M T De Troya

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

Rapport sur l'activité du CEN/TC 38
1983 - IRG/WP 2204
M Pottevin

CEN Draft Standard (38 N 460F): Méthode d'essai pour determiner l'efficacité d'un produit de préservation du bois en milieu marin
1986 - IRG/WP 4132 F
G Castan

Rapport sur l'activité du Comité CEN/TC 38 "Méthodes d'essais des produits de préservation des bois" du Comité Européen de Normalisation (CEN)
1986 - IRG/WP 2266
G Castan

Interspecific variability of European oak durability against white rot fungi (Coriolus versicolor): Comparison between sessile oak and peduncle oak (Quercus petraea and Quercus robur)
2001 - IRG/WP 01-10393
The knowledge of wood natural durability against biologic predators enable its external use. The resistance of European oak wood was reported like durable according to the EN 350-2. However, some individuals may contain high durable wood. Our research was focused to understand this variability in oak population that represent the first french species (4.1 millions of ha). Natural durability of European oak heartwood (Quercus petraea and Quercus robur) against white rot fungi (Coriolus versicolor) was tested according to european standard EN 113. The experimental material consists in 23 oaks robur and 26 petraea oaks sampled from 9 French regions. For each tree, 3 twin samples were taken off from heartwood situated at 1.30 m from the bottom of the tree. Different effects were tested by hierarchic variance analysis: "species", "forest within species" and "tree within forest". The tree effect is very significant for biologic natural resistance. Variability between species was also demonstrated. Although the species effect is significant, it's relatively weak compared with tree differences (it was declared significant 5%). Durability classification was determined according European standard EN 350-1. 69.2% of petraea oak trees are classified as high durable, 19.2% durable, 7.7% moderately durable and 3.8% slightly durable. In the case of robur oak 91.3% of trees are classified as high durable and 8.7% durable.
N Ayadi, B Charrier, M Irmouli, J P Charpentier, C J Allemand, F Feuillat, R Keller

Depletion of boron and copper from CCB treated test specimens using different leaching protocols
2004 - IRG/WP 04-50208
The objective of this study was to measure the depletion of inorganic wood preservative components regarding the proposed OECD guideline "Estimation of emissions from preservative-treated wood to the environment: laboratory method for wooden commodities exposed in the use class 4 and 5" as part of the project "Investigations concerning the influence of test parameters on the release of biocidal actives from treated timber in leaching tests". Pine sapwood specimens (50x10x150) were pressure impregnated with CCB according to European Use Class 4. Before leaching all samples were stores 4 weeks for fixation. In addition leaching tests were performed according to the European Standard EN 84 by means of EN 113 blocks. Parallel investigations were carried out between two laboratories to assess the repeatability and comparability of the methods. The results of chemical analysis of leachates taken at different time intervals show that similar depletion rates were determined for copper and boron independent on the leaching protocol used. However, the loss of copper as well as chromium in short term dipping experiments was often lower than the detection limit. Furthermore it can be stated that the difference between parallels was higher for the results which were obtained for the OECD guideline that EN 84. A comparison of both laboratory results indicate that a quite good repeatability is given in case of the CCB treated material.
E Melcher, R-D Peek, U Schoknecht, R Wegner

Resistance of the wood of Eucalyptus saligna and Paulownia tomentosa against some wood rotting fungi
1997 - IRG/WP 97-10238
Paulownia tomentosa and Eucalyptus saligna are not autochthonous species in Slovenia and we determined the resistance of their wood against our most common wood rotting fungi. The resistance against Coniophora puteana, Gloeophyllum trabeum and Trametes versicolor was determined according to EN 113 and compared to the resistance of beech (Fagus sylvatica) wood. It was stated, that both paulownia and eucalypt wood samples are much more resistant than beech wood. Especially paulownia wood was outstanding by its natural resistance against tested basidiomycetes.
F Pohleven, M Petric

Determination of the preventive efficacy against wood destroying basidiomycetes fungi, EN V 839 - CEN/TC 38 WG 9
1993 - IRG/WP 93-20015
The WG 9 of CEN TC/38 has presented to EC a mycological test to assess efficacy of preservatives applied by surface process. This method is now an experimental standard (EN V 839) which has to be approved by the different european delegations. The following paper is not the standard as it has been proposed but is a presentation of the principle of the method. The experimental standard specifies a laboratory method of test which gives a basis of the assessment of the preventive action of a wood preservative when applied as a surface treatment against Basidiomycetes fungi. This method is applicable to formulations of preservatives in a ready to use form (organic formulations, organic water-dispersible formulations, water-soluble materials). Series of susceptible wood species specimens are treated on longitudinal faces whith the preservative in test using brushing as surface procedure. Test specimens are then exposed by an intermediate mesh to feeder blocks infestedby pure culture of Basidiomycetes fungi in sterile conditions and penetration of fungi is assessed on cross section sawn in the samples at the end of the test.
D Dirol

Proposals for collaborative work on laboratory soft rot testing
1986 - IRG/WP 2265
Proposals for collaborative experiments based on soil burial are presented. It is intended to study the use of defined horticultural loams with a view to obtaining more reproducability in laboratory soft rot tests.
D J Dickinson, S M Gray

A comparison of the effectiveness of a vacuum oven and a wind tunnel in the accelerated ageing of treated wood by evaporation
1989 - IRG/WP 2334
R J Orsler, G E Holland

Bibliographie sur les produits organiques en solvant pour la préservation du bois
1971 - IRG/WP 38
H Alliot

Tebuconazole, a new wood-preserving fungicide
1990 - IRG/WP 3634
TEBUCONAZOLE, an anti-fungal triazole compound, has been tested to assess the effectivness as wood preserving fungicide. Tests were made with the active ingredient and also in formulations against basidiomycetes, blue-staining fungi and mould. Results of the DESOWAG laboratories and also from official institutes will be presented. In addition to this there were made different toxicological and ecotoxicological trials according to OECD and EPA guidelines
B Wüstenhöfer, H-W Wegen, W Metzner

Report of field test results for dichloro-n-octyl-isothiazolone: A potential new wood preservative
1988 - IRG/WP 3495
In a previous report (IRG/WP/3306) we presented preliminary laboratory test results on 4,5-dichloro-2-n-octyl-4-isothiazolone (RH 287). Laboratory data indicated toxic threshold values for RH 287 ranging from 0.37 to 0.50 kg/m³. In this report we present field test results on an IRG L-joint test and an in-ground stake test for RH 287, pentachlorophenol and biocide free test units. (a) L-joint test: After 39 months exposure (Starkville MS.) units pressure treated with 0.05 kg/m³ RH 287 rated 9.7 out of 10. Units dip treated in a 0.5% ai solution of RH 287 rated 10 out of 10. Biocide free controls exposed in the same series rated 5.3 out of 10 after 39 months (b) Stake test: After 48 months exposure in two southern US test plots stakes treated with neat RH 287 in toluene at 4.6 kg/m³ rated between 8.6 to 8.8 out of 10 for decay and 9.1 to 9.8 out of 10 for termite attack. Biocide free control stakes rated O out of 10 for decay and 1.1 to 4.8 out of 10 for termite attack after 48 months. RH 287 continues to show promise as a potential new wood preservative. Results to date were obtained in samples treated with neat RH 287, Formulation of RH 287 into treatment systems specifically designed for above ground or ground contact applications should only improve the already excellent activity seen with RH 287.
D E Greenley, B M Hegarty

Climate indices at work: Above ground decay L-joint tests (EN 330 and AWPA E9) at two sites 12000 km apart and with Scheffer climate indices of 60-65 and 300-330
1996 - IRG/WP 96-20095
Matched sets of Scots pine sapwood (Pinus sylvestris) L-joints were exposed above ground at two field sites for approximately five years. One site, at Garston, Watford, UK has a climate index between 60 and 65 while the other, close to Hilo, HI, USA has an index between 300 and 330. The joints were treated with a range of organic solvent treatments applied either by three minute dip immersion or by double vacuum. Untreated joints were installed at each site as control material. All samples were assessed at approximately annual intervals at both sites. After five years, decay at the Hilo site is well advanced with failure apparent in many joints, both untreated and treated. As would be expected given the climatic differences, decay at the Garston site has progressed more slowly than in Hilo. Differentiation in treatment performance was apparent after one year's exposure in Hilo with similar differentiation becoming apparent after five years' exposure in Garston. This acceleration correlates well with the difference in Climate Index for the two sites as calculated using the Scheffer method. Encouragingly, the performance ranking of the different treatments at the two sites was very similar. The results of this test suggest that the concept of using high decay hazard sites for field testing of treated wood products for use in above ground situations can provide meaningful results in a short period, and may offer a timely and realistic alternative to relative preservative testing to that achieved in laboratory test regimes. The results also show that above ground field testing at both of the sites included provide valuable information on preservative performance, and this information is likely to provide a greater degree of realism than is possible using pure culture laboratory test procedures.
A F Preston, K J Archer, D M Roberts, J K Carey, A F Bravery

A natural exposure weathering test for the evaluation of preservative performance
1992 - IRG/WP 92-2400
Natural exposure weathering tests were carried out by externally exposing treated wood samples for varying periodes of time up to 36 months. In the laboratory these samples were assayed for residual preservative effeciveness using Coniophora puteana FPRL 11E. The results indicated a loss in efficacy over and above that determined using artificial ageing procedures such as EN73 (evaporative ageing) and EN84 (water leaching). Results for two TBT based preservatives indicated a gradual loss in efficacy. Results for the organic biocide 2-thiocyanomethyl-thio benzothiazole (TCMTB) gave a more rapid loss in effeciveness indicative of the high levels of microbial actifity present in the samples. This test provides an intermediate evaluation of preservative performance and permanence between artificial laboratory ageing procedures and the necessary field evaluation using an L-joint type test.
J Brown, G R Williams

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