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Biological detoxification processes - A check list for assessments
1998 - IRG/WP 98-50120
The number of scientific publications on the biological purification of preservative treated wood implies that the biological treatment of wood wastes becomes more and more important. But an information about a successful industrial application is almost missing in all cases. Therefore the applicability of the proposed purification processes is often uncertain. The feasability of such a biological process is assessed exemplary on a method developed at the Federal Research Centre for Forestry and Forest Products. After some large scale-up experiments the investigations were finalized in 1997. An industrial application is unlikely although the process worked in the lab-scale. This critical assessment shows, that - under the given legal restrictions of Germany - the process can not compete with other waste management processes. The evaluation includes the amount, availability and suitability of preservative treated wood waste as well as the process itself, the properties of the purified product and its possible use. The aspects taken into account upon the valuation of the BFH-process are drawn up in a check list. This check list might be a guide for assessing other biological processes and pin-point important questions which should be answered before the industrial application starts or before further investigations are initiated.
H Leithoff, R-D Peek

Less environmental impact of wood preservatives by considering the risk of attack in addition to the hazard class system
1995 - IRG/WP 95-50040-10
Hazard classes, which are standardized in Europe in EN 335, are most useful to direct chemical wood preservation towards the organisms which may attack wood in the various fields of utilisation. However, hazard only signifies the fact that an attack may occur without considering the actual risk to attack. To minimize the application of chemicals with respect of less environmental impact it is necessary to consider both, the hazard of attack and the risk which implies the probability, how often attack may occur and how important this will be. In addition, also the consequences of the failure of a wooden commodity will influence the need of chemical wood preservation. It is therefore proposed to combine the hazard classes as specified in EN 335 or in similar non European regulations with a risk assessment including time assessment as a basis for the requirement on chemical wood preservation. For this, details are given in the paper.
H Willeitner

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

Biological and chemical investigations for the assessment of the environmental impact of wood preservative components
1999 - IRG/WP 99-50127
This study was carried out in order to investigate the suitability of biological and chemical techniques to evaluate the environmental impact of wood preservatives depleted from impregnated wood. Small specimens (15*25*50 mm3) of Scots pine sapwood (Pinus sylvestris) were treated with a CCB salt. After fixation the treated and untreated samples were washed-out according EN 84, and the different leachates were added continuously on the top of soil columns (lysimeters). The pure wood preservative was used as a reference. After certain time intervals the eluate was separated and the content of ions was analysed. A couple of these solutions were selected to determine their toxicity against luminescent bacteria and daphnia. First results show that the solutions containing the pure wood preservative show highest toxicity against the aquatic micro-organisms used in this test. The values for the leachate containing wood preservative are comparable with data for the wood preservative-free solution. The results clarify that the analytical measurements well correspond with the biological tests on ecotoxicity.
E Melcher, H-W Wegen

Categories in wood preservation hazard, risk, and use
1994 - IRG/WP 94-20048
In various countries hazard-, risk-, or use-categories have been established. The different terms seem to be only a sophisticated language problem, but they are rather a basic principle of the philosophy of wood preservation which is going to obtain importance with respect to the low reputation of chemical wood preservatives in an increasing number of countries. Whilst hazard signifies the fact that an attack may occur, the term risk implies the probability how often and how important attack may be. It further includes the consequences of a failure. Both are orientated towards the organisms, which may involve problems when using wood or wood-based products. Use-categories are directed towards the utilization of the material possibly or not exposed to an attack. The author is convinced that for the future of wood preservation it is essential to combine the hazard of possible attack with a risk assessment for the probability and the consequences of an attack. In addition, also a time assessment is needed to consider the intended service life of a timber component. Only a combination of these influences will lead to the most suitable way of wood protection under environmental impact conditions.
H Willeitner

A new preservative - A double-edged sword
1990 - IRG/WP 3573
Increasing environmental pressures on the use of pesticides throughout the world will impact more on the use of all wood preservatives. In particular the use of traditional wood preservatives and methods of application are under close scrutiny. The industry is responding to the challenge of developing alternative products and systems but faces great problems due to the excellent performance and safety record of traditional preservatives. Current research in preservation is aimed at producing more so-called "environmental friendly" preservatives. Developments to date have not produced alternatives which are as effective for long term performance and still have their own associated health and environmental hazards when compared to traditional products. The problems encountered in the introduction of new preservatives are illustrated by reference to case histories. The changes in standards and improvements in processing techniques for established preservative treatments are described. The need for effective handling and containment procedures to minimise risk with new as well as traditional preservatives is discussed.
M Connell, J A Cornfield, G R Williams

The assessment of biological and mechanical properties of wood treated with ionic liquids – N,N-dimethylamine and 1-decylimidazole derivatives
2012 - IRG/WP 12-40582
This paper presents the results of tests of the effectiveness of action of new imidazolium and bis-ammonium ionic liquids against Basidiomycotina and Ascomycotina wood-destroying fungi. All the investigated ionic liquids showed high fungicidal action against Coniophora puteana. In order to characterize the influence of ionic liquids on mechanical wood properties, the compression strength along the grain was investigated. The obtained results showed that impregnation of Scots pine sapwood with ionic liquid: [1,9-(2,8 dioxanenano]bis(dimethyloctylammonium nitrate) had no negative effect on the compression strength parallel to grain. The investigated compounds characterised by thermal stability, may be applied as biologically active components of wood impregnates in combination with other biocides.
W Przybylska

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

Biological assessment of bio-based phase change materials in wood for construction applications
2022 - IRG/WP 22-40935
Solid wood can serve multi-functionality for energy savings in buildings. The study reveals the results of bio-deterioration and degradation of solid Scots pine wood used to incorporate single or multicomponent fatty acid mixtures as bio-based phase change materials (BPCMs). The sapwood samples were impregnated with capric acid (CA), methyl palmitate (MP), lauryl alcohol (LA) and a mixture of coconut oil fatty acids and linoleic acid (CoFA-LA). The samples were tested against subterranean termites by an Italian species (Reticulitermes lucifugus), the wood boring beetle Hylotrupes bajulus and mould through a discoloration test. Tested against termites, the impregnated samples were significantly less susceptible to the attack than the controls, i.e. the tested BPCMs were resistant to R. lucifugus. The only test with MP terminated at the moment against H. bajulus showed positive results with no larvae survived. The mould discoloration test revealed that the wood impregnated with CoFA-LA was identically susceptible to mould discoloration when compared to the control, non-impregnated samples. This pioneer study verifies that solid wood employed for encapsulation of BPCMs for building purposes can serve identically or somewhat better than similar wooden building elements regarding attacks of the above microorganisms and insects. Such multifunctional building elements will be tested further in a pilot scale building to characterize better the durability aspects of the new materials.
S Palanti, A Temiz, G Köse Demirel, G Hekimoğlu, A Sari, M Nazari, J Gao, M Jebrane, T Schnabel, N Terziev

Danish wood preservatives approval system with special focus on assessment of the environmental risks associated with industrial wood preservatives
2001 - IRG/WP 01-50166-01
The following is a description of the procedure used by the Danish Environmental Protection Agency to assess the environmental risks associated with preservatives used in the pressure impregnation of wood. The risk assessment covers issues considered to be of significance for the environment and which are adequately documented so as to allow an assessment. Such issues are persistence and mobility in soils, bioaccumulation and the impact on aquatic and terrestrial organisms. Unless required in special circumstances, the assessment does not apply to birds and mammals as the normal use of preservative treated wood is not expected to involve any noteworthy exposure of these groups. Approval of wood preservatives will be based on a general assessment of the environmental risk associated with the normal use of wood treated with the preservative in a realistic worst case situation. The assessment may address other aspects such as disposal and total life cycle.
J Larsen

Programme section 2, Test methodology and assessment
1997 - IRG/WP 97-20126
IRG Secretariat

Biological screening assays of wood samples treated with creosote plus chemical additives exposed to Limnoria tripunctata
1980 - IRG/WP 408
Laboratory methods for exposure of treated wood coupons to Limnoria tripunctata are described. Chemical additions to creosote were screened using this method. Three pesticides, Endrin, Kepone, and Malathion proved particularly effective. The addition of varying percentages of naphthalene to creosote using several treatment methods are currently being assayed. Results to date show that the coupons treated by the empty cell method have better performance than those prepared by the toluene dilution method. The naphthalene coupons treated by the full cell method show no attack after six months' exposure.
B R Richards, D A Webb

Penichroa fasciata (Stephens) (Col. Cerambycidae) a pest in wood materials
1988 - IRG/WP 1365
Penichroa fasciata (Stephens) (Col. Cerambycidae) is found to be a frequent pest occurring in hardwood in storage in Italy. This paper reports the characteristic for identification, biological features, distribution and timber liable to attack.
A Gambetta, E Orlandi.

Proposed methodology for the assessment of safety indexes
1990 - IRG/WP 3562
Safety Indexes (SI)s are developped on the same concept as Efficacy Indexes (EI)s: EIs are retentions of wood preservatives (percentages of the critical values "efficacy") which are presumed efficient for a given biological class of risk. In the same way, SIs are retentions of wood preservatives (percentages of the critical values "safety") which are taken as acceptable for human health and the general environment. EIs and SIs as well are derived from different types of bioassays and related to objectives of quality which may be either regulatory or harmonized within the programmes of the Standard Committees (CEN TC/38 for example). Critical Values are characteristics of wood preservatives; EIs and SIs are characteristics of treated wood; they vary with the different classes of risks.
G Ozanne

New technique to analyze impregnation processes
1988 - IRG/WP 2304
Equipment has been developed to measure liquid flow in wood during impregnation processes. Basic principles of flow measurements using directly heated negative temperature coefficient thermistors, and some characteristics of the hardware developed are presented in this paper.
J P Hösli

Thermal treatment of wood: European Processes and their background
2002 - IRG/WP 02-40241
Recent efforts on thermal treatment of wood lead to the development of several processes introduced to the European market during the last few years. The total production capacity of heat treated wood in 2001 is estimated as approx. 165.000 m3. In the paper the different heat processes are presented. The general technology as well as scientific data on the chemical transformation of the cell wall polymers, on the biological performance, on the physical and mechanical properties of the treated wood are presented and discussed
H Militz

Biological control of the Formosan subterranean termite Coptotermes formosanus Shiraki
1971 - IRG/WP 100
M Tamashiro, J K Fujii, P Lai, T E Richardson

Quantitative assessment of the condition of field specimens
1981 - IRG/WP 2154
Suggestions for a discussion on the desirability of an extension to the existing procedure of assessment of the condition of field specimens by adding more objective, reproducible methods in order to obtain earlier and more specific information than at present on the effect of biological attack on strength and other properties of the specimens as well as the time aspect.
H Friis-Hansen

Wood preservation in France. "Bois plus" chain of quality. Description of the scheme early 1989
1989 - IRG/WP 3519
1989 - description of the French "CTB-BOIS PLUS" homologation scheme...
G Ozanne

Biological control with Trichoderma harzianum in relation to the formation for spores the production of soluble metabolites
1994 - IRG/WP 94-10073
The amount of spores produced by three strains of Trichoderma harzianum on the aerial mycelium of agar cultures and in shake cultures, respectively, correlated with the inhibition zones exerted against Phanerochaete chrysosporium in an agar diffusion test. The amount of soluble antifungal metabolites as well as the protein content also correlated with the inhibition zones and the amount of spores produced. The antifungal metabolites were identified to be trichorzianines. They were the only compounds with antifungal activity. It is concluded that the trichorzianines are responsible for the biocontrol effect by soluble metabolites and that they are produced during conidiogenesis.
J Bürgel, E Horvath, J Haschka, K Messner

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

Physical and biological properties of albizzia waferboards modified with cross-linking agents
1995 - IRG/WP 95-40043
Chemically-modified low-density waferboards with cross-linking agents were produced using a fast-growing species of hardwood albizzia (Paraserienthes falcata Becker) as a raw materials and isocyanate resin as a glue adhesive. For the chemical modification, the vapor-phase formalization of the boards and the pad-dry-cure treatment of wafers with cross-linking agents were employed. The vapor-phase formalization was conducted for 5, 10 and 24 hours using tetraoxane as a source of formaldehyde, and the pad-dry-cure treatments with glutaraldehyde and ethyleneurea compound (DMDHEU) were made after impregnation of their 5 and 10% aqueous solutions of each chemical. Sulfur dioxide was used as a catalyst in both treatments. About 70% of antiswelling efficiency (ASE) was gained in all treated boards irrespective of reaction time or solution concentration. All treated boards were very stable to water soaking even in the 2-hour boiling on thickness swelling as well as linear expansion. Laboratory tests with brown-rot and white-rot fungi revealed that decay was completely suppressed in formaldehyde-treated boards, and small losses in weight were counted in other treated boards. All treated boards were also effective in resisting to the attack by the destructive termite Coptotermes formosanus.
S Yusuf, Y Imamura, M Takahashi, K Minato

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

La rôle de l'expert dans l'évaluation toxicologique
1990 - IRG/WP 3589
C Boudene

Working Group I 'Biological Problems' Sub-group 'Insects in dry wood (other than termites)', Scope of work
1976 - IRG/WP 152
S Cymorek

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