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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


Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)
2005 - IRG/WP 05-30373
The chemistry analysis of the compounds present in dichloromethane and ethanolic fraction as well as bioassays enables to understand the durability differences of Eperua falcata and Eperua grandiflora. The principal distinction between these two species is the acidic subfraction of diterpenoic extract, which is antifungic in Eperua falcata when tested in in-vitro conditions. This study also enables to show that ethanolic fraction plays an important role in the mechanism of natural durability. It also reports the first isolation of cativic acid in Eperua falcata wood.
N Amusant, C Moretti, B Richard, E Prost, J M Nuzillard, M-F Thévenon


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


Biological Durability of Laminated Veneer Lumber from Durable and Non-Durable Wood Species
2005 - IRG/WP 05-10567
Laminated Veneer Lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.
P Nzokou, J Zyskowski, S Boury, D P Kamdem


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 biological natural durability of timber in ground contact
1994 - IRG/WP 94-20051
The BRE ground contact field trials for the determination of the biological natural durability of different timber species have recently been reviewed. The data obtained from these trials have been used to appraise the different ways in which natural durability may be expressed. It is concluded that the use of the mean as a method of assigning the timber to one of five durability classes may be acceptable where general recommendations are required, for instance in association with the use of wood preservatives to enhance durability, but that the median provides a better indication in this context. Where a specifier requires more detailed information on timber performance, the mean (or median) is inappropriate and a system of percentile values would be more informative.
G A Smith, R J Orsler


The chemical analysis and biological evaluation of wood extractives as potential timber preservatives
1995 - IRG/WP 95-30090
Work involved the biological performance of water and organic solvent soluble extractives of four naturally durable wood species, namely; Matumi, Tamboti, Sneezewood and the Turpentine tree. These timber species are known to be naturally durable against termites and fungi (±25 to 35 years). The extractives were evaluated against termites and fungi using impregnated pine pencil stakes in field tests and soil burial trials over a 2 year period. C13NMR analysis of extractives isolated from the wood was carried out to try and identify the key chemical components which might impart durability with a view to prediction of new potential wood preservative formulations.
P Turner, D Conradie


An in-ground natural durability field test of Australian timbers and exotic reference species. Part 5: Extensive data from a site where both decay and termites are active. Results from a full-replicated set of heartwood specimens from each of ten myrtaceous hardwoods after 18, 19 and 20 years' exposure - A discussion paper
1988 - IRG/WP 2324
Extensive data are presented on the decay situation, the termite situation and the decay-termite associations; all gathered from a fully-replicated set of heartwood specimens of 10 hardwood timbers after 18, 19 and 20 years' exposure in the ground at a single test site, i.e. a semi-arid steppe site. Sixteen tables are presented in addition to the one table providing the rating data; the latter representation of specimen condition being essentially all the data normally being recorded from field tests, whether these be of natural durability or preservative treated specimens. The authors give this "extra" data to show the type of information obtainable as a result of applying both mycological and entomological expertise to field assessments. Instead of discussing these results. the authors wish to generate some discussion by asking questions such as - is some of all of this information of value? - What additional/alternative information would interested scientists wish to see with respect to the most durable timbers in a test such as that examined in this report?
J D Thornton, G C Johnson, J W Creffield


European standardization for wood preservation. Progress report 91-92
1992 - IRG/WP 92-2398
Since the IRG 22 conference in Kyoto, CEN/TC 38 Plenary met twice in relation with several working group meetings. 5 upon 6 of the interpretative documents have been prepared by adhoc groups of the Standing Committee for Construction within the scope of the 89/106/EEC directive on Construction Products. The expected requirements attached to wood preservation are both requirements 1) and 3): 1) mechanical resistance and stability; 3) hygiene, health and the environment. A consequence should be a redrafting of the previous official mandate delivered on September 27, 1989: - direct mandate on wood (solid and reconstituted) as well as wood preservatives as construction products - horizontal joint-mandates on wooden-commodities in relation with the other TCs in charge of such commodities. Another consequence is a formal exploration by TC 38/WG 11 "Permanence of active ingredients in treated timber" through a first couple of standards entitled "methods for measuring losses of active ingredients and other preservative ingredients from treated timber - Part 1: Laboratory method for measuring losses by evaporation to air - Part 2: Laboratory method for measuring losses into fresh water or salt water". This works anticipates the mandate and means that TC 38 is currently making progress, towards air and water quality. Apart from building activities, TC 38 got also by the end of 1991 an order of standardization on Creosote, and Creosoted-timber following the 13th adaptation of 76/169/EEC Diretive Creosote specifications. This additional event results from the trend in Brussels to develop the so-called "new approach" where the EC authorities elaborates essential requirements with mandates to CEN explicit them in close cooperation with the industry.
R Hüe


Increased biological durability differs for traditional wood preservation and new non-biocidal systems (NBS)
2000 - IRG/WP 00-20212
Wood preservation is a way to increase the biological durability of wood by the addition of chemical components with a biocidal effect. The effect of such treatment is clearly concentration dependent. At distinct levels of fungicide concentration fungi are killed or inhibited in their enzymatic functioning to provide nutrients. The toxic limits allow decision-makers to provide treating prescriptions based on a teared approach of European standards. Non-biocidal treatments may act totally different. Mechanisms as moisture exclusion or hydrophobation and modification of wood components inhibit, retard or stop the colonisation by fungi. Though these treatments are only effective from certain levels on or when a certain degree of substrate modification is reached, it is hardly possible to establish a dose response curve. Since these treatments do not fit into the standard methodology for evaluation of traditional wood preservation either new test methods or at least new ways of judgement and interpretation of results are required.
J Van Acker, M Stevens


Testing biological durability of wood-plastic composites
2006 - IRG/WP 06-20347
Testing biological durability is inherently different for wood-plastic composites (WPC) compared to solid timber. However there is clearly a need for more information on the durability of WPC’s, on the effect of decay on the material properties of WPC’s and on methods for assessing decay of WPC’s. For the emerging European WPC market there has been some discussions on how to work on these topics. Laboratory testing is focussing on using the most appropriate test methods from the wood durability testing. Basidiomycete testing as was developed for wood based panels is proposed and soft rot testing can be done in accordance with laboratory methods for the evaluation of natural durability. There is however concern on the pre-leaching or pre-conditioning required to be in line with the slow water uptake of most modern wood-plastic composites. This is also of concern when dealing with field testing and probably will require out of ground contact testing with extra control of the moisture balance. It is also relevant that testing will become a requirement when dealing with the EU Directives on biocides (BPD) since many wood plastic composites contain fungicides and the one on construction (CPD) when load bearing applications are envisaged. Finally it is considered important to benchmark the WPC products concerning their biological durability with commonly used wood based products for different commodities allowing as such a better prediction of service life.
J Van Acker


Further discussion of biological durability assessments of acetylated wood from several European institutes
2006 - IRG/WP 06-40340
In the last decade, interest in the development of wood modification systems has increased in Europe. Alongside several industrial initiatives for heat treatments, there have also been scaling up and pilot plant projects for chemical wood modification. Between 2000-03, the European Commission funded the "Thematic Network on Wood Modification". This paper features a re-evaluation of work undertaken within that project, assessing the performance of acetylated radiate pine. This re-evaluation comes at a time when acetylated radiate pine is due to be commercially launched. This corresponded with one of the key decisions of the Network, in that modified wood should be regarded as a new wood species, and tested accordingly, with particular emphasis on biological durability and dimensional stability.
D Jones, W Homan, F Bongers


Biological Protection of Composite Panel from Moulds and Decay
2007 - IRG/WP 07-10612
Composite panels, such as oriented strand board (OSB), are widely used in house construction in North America. These structural panels are normally made of non-durable wood species and are susceptible to moulds and decay when exposed to wet conditions. Building envelope failures due to moulds, decay or poor construction practices can negatively impact the image of wood. To ensure durability of composite panels, the most important consideration is the use of mould- and decay-resistant wood species to prevent fungal attack. Using low environmental impact technology to improve the durability of composite products could have market-related advantages over using chemical protection products. This research aimed to explore various potential biological treatments to protect composite panels from biodegradation, and to increase durability of panels for better resistance to mould and decay infection in service.
Dian-Qing Yang, Xiang-Ming Wang, Hui Wan


The effect of gamma radiation on selected wood properties
2008 - IRG/WP 08-40394
As an easy, fast, and effective sterilisation method, gamma irradiation changes molecular structures not only in pest’s living cells, but also in wooden cell walls. Radiation-induced depolymerisation causes significant changes in some properties of wood crucial for restoration and for laboratory testing of wood-preservative effectiveness. The influence of gamma radiation concerning total amount of water-soluble carbohydrates (TSC), maximum swelling (aMAX) and resistance to impact milling (RIM) were investigated. Cobalt (60Co) was used as gamma source and Scots pine sapwood (Pinus sylvestris L.) was irradiated with dosages of 30, 90 and 150 kGy. A strong linear correlation between TSC and the radiation dosage was found. Leached irradiated specimens had significantly greater TSC than non-irradiated controls. RIM decreased significantly and linearly with increasing radiation dosage. After leaching, the linearity between these parameters was improved. Gamma radiation had no significant effect on aMAX and the elapsed time after irradiation did not influence aMAX, RIM, and TSC.
R Despot, M Hasan, A O Rapp, C Brischke, C R Welzbacher


Ensure Durable Wood-Frame Construction under the Climate and Biological Hazards in Shanghai
2009 - IRG/WP 09-20413
This paper provides technical background for developing durability-related provisions for the Shanghai wood-frame construction code. It summarizes the related climate, decay and termite hazards in this area as well as traditional durability solutions used for wood and wood hybrid constructions in China. The overall durability principles or philosophy used throughout this durability chapter are to improve and ensure building durability using integrated protection methods by appropriate design and construction and by using preservative-treated or naturally durable wood where necessary. Of these principles, durability by design is taken as the most fundamental approach for achieving good long-term performance of a building as a whole, and using durable wood where necessary to ensure the durability of individual components. This chapter covers moisture and termite management, and whenever possible multiple lines of defence are provided. Meanwhile, the practical side is also taken into consideration in order to make sure that all measures are buildable on construction sites with a reasonable cost.
Jieying Wang, Chun Ni, Jiahua Zhang


Biological Treatment to Improve Wood Product Quality and Durability - Fifteen Years of Effort and Experience at FPInnovations-Forintek Division
2009 - IRG/WP 09-40444
Wood plays an important role in the world economy. However, wood is subject to attack from wood-degrading fungi and insects and durability and quality of wood products are becoming increasing concerns for consumers. Development of effective and low environmental impact technologies to improve wood product quality and durability will be required to address these concerns. The application of a biological treatment to wood products is an example of one such technology. During the past fifteen years, a series of research projects were conducted at FPInnovations–Forintek Division to explore and develop various biological technologies and treatments to improve wood quality and durability against mold, stain and decay. These projects included 1) biological protection of logs and green lumber from mold, stain and decay; 2) biological pre-drying of wetwood lumber; 3) biological treatment to improve wood panel durability; 4) biological modification of wood to reduce resin use in panel manufacturing; and 5) biological incising to harden wood. This article summarizes the significant technical breakthroughs and findings made in these studies.
Dian-Qing Yang


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


Moisture dynamics of WPC as basis for biological durability
2010 - IRG/WP 10-40520
The largest market for wood-polymer composites (WPCs) is currently decking. Although many products are commercially available, a proper standard for the assessment of the biological durability of WPC does not exist. Recommended standards for testing resistance against basidiomycetes should be completed with a method to bring the specimens in a worst case situation, obtaining a moisture level high enough to initiate and support fungal growth at the beginning of, or early in the test. In this study a simple, but efficient way to increase the moisture level of test specimens of 9 commercialized WPC decking products is presented. The 24 h air-drying period after 4 weeks immersion in warm water strongly reduced the high moisture content (MC) of the wood particles, but the induced thickness swell may allow a quicker re-moistening. Performing a fungal test with these moistened specimens, Coriolus versicolor caused 2 – 15% mass loss (ML) and Coniphora puteana 1 – 12% ML despite of the poor virulence of latter fungus. ML was correlated with the MC after incubation and the thickness swell due to the pre-treatment. The ability of fungal spores to settle on WPC surfaces was investigated as well by placing specimens in a cabinet loaded with mist saturated with fungal spores and an equivalent outdoor test setup. Linking results to the composition or production process is difficult and was not the main goal of this research, but PVC based materials clearly performed the worst: high water absorbing and thickness swell, the highest ML in lab-based fungal testing and the most distinct fungal staining during outdoor exposure.
N Defoirdt, J Van Acker, J Van den Bulcke


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


Effect of Coatings on the Durability of Birch and Spruce Plywood. Part 2: Biological Durability
2010 - IRG/WP 10-40527
Several different coated birch and spruce plywood types were investigated in Finland using the combination of outdoor weathering and decay test EN 12038. The most important factor to affect on the biological performance of birch plywood, coated and uncoated, was edge sealing. For spruce plywood edge sealing had a smaller effect. However, in spite of positive effect against decay, edge sealing did not prevent wetting during the decay test. One year outdoor weathering did not have a significant effect on painted plywood when compared to samples stored in the laboratory.
A Nurmi, H Viitanen


Limited variability in biological durability of thermally modified timber using vacuum based technology
2011 - IRG/WP 11-40567
The SmartHeat® thermal timber treatment is a new technology based on the process parameters being steered very precisely mainly due to the vacuum applied and heating system involved. Timber treated with this technology shows a potential for less variability of biological durability in one batch. Several batch treatments were sampled and assessed on statistical variability of decay resistance against Basidiomycetes and soft rotting micro-fungi according to lab testing as described in the standards CEN/TS 15083 part 1 and 2 respectively (only Basidiomycetes test results are reported in this paper). By means of Weibull distribution assessment it was possible to show that variability in biological durability of each treated beam is well controlled and that this variability is limited compared to natural durability of wood species. Lower treatment variability due to precise parameter control for each beam and limited deviations of process parameters within the treating vessel are considered the main contributing factors. The paper also states that lower control of process parameters of some heat treatment processes might induce higher variability of the obtained biological durability than a customer might expect.
J Van Acker, S Michon, J Van den Bulcke, I De Windt, B Van Swaay, M Stevens


Biological durability of natural fibre reinforced composites
2014 - IRG/WP 14-40681
Composite materials reinforced with wood or non-wood natural fibres have the potential to be a lighter and lower-cost alternative construction material. Until better availability and properties and a lower cost price of degradable polymers makes their use more prevalent, the application of natural fibre reinforcements in synthetic polymers is an intermediate step towards products that are completely degradable or compostable after their service life. The inherent degradability of natural fibres makes the circumstances of their composite applications, more specifically the moisture conditions, very important regarding potential development of fungal communities and the related damage. For wood and wood-based panels different Use Classes (UC) are defined and for every UC laboratory and field test methods were developed that each determine the (maximum) potential damage caused by the fungi that act in that specific UC. These tests can be used for natural fibre reinforced composites (NFCs) if the specific slower moisture ab- and desorption are taken into account. However the question arises whether the most appropriate way to assess the material resistance is yet developed. Surface stain or mould fungi develop on NFCs when used in high relative humidity conditions (e.g. UC 2). In UC 3 Basidiomycetes can degrade natural fibres as well as derived composites if the natural fibres reach the critical moisture content. In addition to laboratory tests, a 5 year field test showed that fungal growth is not problematic when moisture traps are not present. Finally a graveyard test (UC 4) only revealed superficial softening after 5 years exposure, confirming the good durability of NFCs. Fungal growth thus seems to be mainly an aesthetical problem. Moisture uptake, more than fungal decay, also results in a decrease in mechanical properties, which seems, up to now, relatively unimportant regarding the actual use of such composites. However, if used in structural applications once a better fibre/matrix adhesion leads to enhanced mechanical properties, the damage by moisture and fungi could become critical.
N Defoirdt, I De Windt, J Van den Bulcke, J Van Acker


Durability of treated wood Corymbia torelliana and Eucalyptus grandis x Eucalyptus urophylla against subterranean termite
2015 - IRG/WP 15-20563
This work aimed to analyze the durability of woods against termite Nasutitermes corniger Motsch. Fence posts from this study were collected in Pinheiros, north of Espírito Santo state, Brazil. Used the Corymbia torelliana and Eucalyptus grandis x Eucalyptus urophylla species with 11 and 9 years, respectively and plant spacing of 3.00 x 2.00 m. Were used 72 samples from discs removed the 0.50 m of fence posts basis. The samples had 1,5 x 1,0 x 2,0 cm (Radial x Tangential x Longitudinal), 36 for each species and 18 for position 0 to 1,5 cm and 18 for position 1,5 to 3,0 in radial deep, treated with 2% active ingredients of CCA type C in oxide base, in diameter classes 8-10 cm; 10-12 cm and 12-14 cm in force feeding test. Measured the heartwood and sapwood content, heartwood: sapwood ratio and retention of CCA in wood. The specifications of the test, weight loss, scores attributed the sampless were taken according to ASTM D 3345 (2005). Statistical analysis was performed using t-test for independent samples for characteristics of the wood. The weight losss and the scores awarded to the specimens were processed to satisfy the principles of ANOVA. Used the Tukey test for the sources of variation detected as significant by F test. The results indicated that the larger weight loss are associated with the radial position 1.5 to 3.0 cm. Probably by not receive preservative solution, because of impermeability of the heartwood. In absolute terms the largest weight loss were observed for wood Corymbia torelliana. The preservative treatment provides high strength hardness, confirmed by the scores close to 10. In general the wood Eucalyptus grandis x Eucalyptus urophylla presented the best characteristics for the preservation.
D Junior Verly Lopes, J Benigno Paes, P N de Medeiros Neto, G dos Santos Bobadilha


Assessment of the biological durability of wood treated with organosilicon compounds
2016 - IRG/WP 16-30685
The European wood construction market is in need of environmentally friendly wood-based products whose service life meets the expectations of end users. Non-biocidal silicon-based water repellents, which can be applied to different materials, help minimize their vulnerability/susceptibility to liquid water. Consequently, they have the potential of increasing wood’s resistance against decay fungi by reducing their ability to absorb water. Moreover, by filling the pores of wood, they may reduce its vulnerability to wood-boring insects and thus improve its durability. In order to determine their suitability as wood protectors, three silicon-based water repellents were applied at different concentrations to samples of Scots pine, beech and oak. The application was either superficial (dipping) or by deep (vacuum impregnation). Durability tests were then performed in order to determine the resistance of the treated wood samples against moulds, blue stain and basidiomycete decay fungi, as well as against Reticulitermes subterranean termites. Additionally, eco-toxicological tests were run in order to select the product which had the least environmental impact. The results demonstrate that the three tested organosilicons exhibit different levels of toxicity and improvement of the resistance of the tested wood species against biological threats. The anti-fungal resistance is lower than that provided by traditional biocidal wood-preservatives, but it is still adequate in applications where short-to-average service-life is acceptable and where maintenance and/or replacement is possible. Termite behaviour and feeding preferences in situations where choosing between treated and untreated wood was possible demonstrated that insects tend to avoid consuming wood specimens impregnated with organosilicons. Wood-based materials with levels of biological resistance which are intermediate between wood’s natural (inherent) resistance and that improved with the help of biocides as well as wood-protection products and processes which allow reaching these levels should be appreciated more. They increase the range of possible end-uses for wooden commodities made of European non-durable wood species such as Scots pine and beech both with regard to the material’s properties and its expected performance.
M Kutnik, M Montibus, S Derocker, S Salivati, J-P Lecomte


Resistance of heat treated Ash wood under steam pressure: rot fungi, soil micro-organisms and termites
2016 - IRG/WP 16-40724
Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood® treatment intensity on wood decay resistance improvement against soil-inhabiting micro-organisms, brown/white rots and termite’s exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of Ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170ºC, 200ºC, 215ºC and 230ºC. The reference materials were untreated Ash, Beech and Pine woods, for each biological test. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungus according to CEN/TS 15083-1 (2005) directives. Durability against soil-inhabiting micro-organisms was determined relating to the CEN/TS 15083-2 (2005) directives, by measuring the Weight Loss, modulus of elasticity (MOE) and Modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis specie was used for the termite’s exposure non choice screening test with a size sample adjustment according to EN 117 (2005) standard directives. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature over 215°C, representing by a wood mass loss (ML %) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever heat treatment conditions, thermally modified ash wood was not efficient against termite’s attacks.
K Candelier, S Hannouz, M-F Thévenon, D Guibal, P Gérardin, M Pétrissans, R Collet


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