Your search resulted in 578 documents. Displaying 25 entries per page.
Effects of acetylation on the dimensional stability and decay resistance of kenaf (Hibiscus cannabinus L.) fiberboard
1996 - IRG/WP 96-40059
The objective of this study was to investigate the influence of the acetylation treated kenaf fiber, Phenol formaldehyde resin content level, and three fungi species on the dimensional stability and decay resistance of high density non wood composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness, length changes, and decay resistance of the high density kenaf fiberboards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Rowell
Wood preservation in Lithuania
2004 - IRG/WP 04-30363
This article is intended to give basic information on wood preservation activities in Lithuania and the main actors in wood preservations practice and research. Currently the main actors in practical Lithuanian wood preservation activity are enterprises of wood preservation industry united by the Lithuanian Wood Preservation Association. The most intensive activity in wood preservation practice and research started after 2001. The only active institution in wood preservation research currently is Lithuanian Forest Research Institute with 2 running projects. Lithuanian University of Agriculture and Kaunas University of Technology are active in standardization and have potential to start research. Main obstacles for future development of wood preservation research are: insufficient interest of industry in research and lack of skilled scientists.
Natural durability transfer from sawmill residues of white cypress (Callitris glaucophylla). - Part 3: Full penetration of the refractory sapwood of white cypress
2000 - IRG/WP 00-40167
The heartwood of white cypress, Callitris glaucophylla, is renowned for its termite resistance and durability against decay. The sapwood, which can represent up to 30% of log volume, is non-durable and refractory to conventional preservative treatment. Previous work ascribes the lack of permeability to oily deposits within tracheids and ray cells. Environmental scanning electron microscopy was used to investigate ultrastructural aspects of sapwood permeability. Several pre-treatment processes to improve permeability were tested with limited success. Solvent drying allowed preservative penetration but damaged the structure of the timber. Neither, long term water soaking nor an oscillating pressure/vacuum cycle had any effect on porosity to water-borne treatments. Through extensive modifications to a standard VPI process we can now repeatedly achieve full penetration with organic solvent-based wood preservative solutions into white cypress sapwood. Effects of this process on the strength of the timber are being evaluated. Work is continuing as to the most effective and efficient treatment schedule and the latest results will be presented at IRG 31.
M J Kennedy, L M Stephens, M A Powell
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
European standardization for wood preservation
1988 - IRG/WP 2321
European standardization for wood preservation
1989 - IRG/WP 2335
The susceptibility of 35 Amazon wood species to Cryptotermes brevis (Walker)
1982 - IRG/WP 1160
Laboratory tests were carried to evaluate the susceptibility of 35 Amazon hardwoods to Cryptotermes brevis (Walker). The results were analysed statistically and showed that five wood species were non resistant, nine were resistant and the other twenty-one in between those classes of resistance.
M D Canedo
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
Durability of larch (Larix spp.) wood against brown-rot fungi
1997 - IRG/WP 97-10228
Durability of the heartwood of Larix decidua, L. sibirica, L. gmelinii, L. gmelinii var japonica, L. gmelinii var olgensis and L. sibirica x decidua against brown rot fungi Coniophora puteana, Poria placenta and Gloeophyllum trabeum was tested according to EN 113 test method. Parallel samples were used to study the amount and composition of wood extractives. The sample trees originated from the research forest of Punkaharju Research Station. The average age of the trees was 60 years. In addition, from L. sibirica also trees at 25 and 102 years were used. Results show that the durability of larch is depending on species, age of the tree, the wood part (inner or outer heartwood) and fungus. The average durability of larch heartwood was equal to class 3 or 4 (moderately or slightly durable, according to the standard EN350:2) and comparable with the durability of pine heartwood (Pinus sylvestris L). However, the durability of L. gmelinii var olgensis and L. sibirica (102 years old) was on the higher level than that of the other studied species but the durability varied even within the same board. Also the durability of wood from L. sibirica grown in the Russian side (Siberia) was studied. It was equal to that of the trees grown in Finland. The average amount of resin acids of larch heartwood was only about 0.1% (dry weight). In contrast, the heartwood of scots pine may contain up to 4.0% of resin acids. Resin acids are found to inhibit the linear growth of certain fungi. Interestingly, the largest amounts of resin acids (0.3%) were found in the heartwood of L. gmelinii which also showed high durability. The concentration of water soluble extracts (mainly arabinogalactan) of larch heartwood was quite large, varying between 3.2 - 20.5%. The concentration of water soluble extracts in the heartwood increased along the age of the trees. Lowest level of extractives were found in Larix decidua which was also the least decay resistant species. The durability of wood in different targets and the role of different chemical compounds of larch heartwood on decay resistance needs to be clarified.
H Viitanen, L Paajanen, P Saranpää, P Viitaniemi
Inspection results of preservative treated stakes, maximum 33 years in field
1992 - IRG/WP 92-3690
Since in 1958, we have undertaken field experiments in Japan. For these field experiments, we used sapwoods of Japanese cedar called Sugi (Cryptomeria japonica) because of majority of plantation forest soft wood species in Japan. For some preservatives, we added sapwood of Japanese beech called Buna (Fagus crenata), a main Japanese hard wood species. Dimensions of these specimens were 30 x 30 x 600 mm³ (T x R x L). About 30 preservatives mainly water born but 20% of oil born preservatives included, were examined for this test. We checked the damage rating every year by the observation. The service life of the preservative treated stakes were estimated at the period when the average damage rating of stakes were reached beyond 2.5 . Creosote oil, creosote oil mixed heavy oil (75:25 and 50:50) and creosote oil mixed coal tar (75:25 and 50:50) are still sound conditions for 33 years. CCA (JIS K 1554 Type 1) 2% and Tancas C 2% are still sound conditions for 28 years. Because of soft rot, the treated Buna specimens were shorten as ones of treated Sugi.
K Suzuki, K Yamamoto, M Inoue, S Matsuoka
Wood furfurylation process and properties of furfurylated wood
2004 - IRG/WP 04-40289
The first processes for “furfurylation” of wood (wood modification with furfuryl alcohol) were developed several decades ago. Furfuryl alcohol is a renewable chemical since it is derived from furfural, which is produced from hydrolysed biomass waste. Over the last decade modernised processes for furfurylation of wood have been developed. These new processes are based on new catalytic systems and process additives. Two main processes for production of furfurylated wood have been developed for WPT (Wood Polymer Technology ASA) by the authors – Kebony 100 for high modification levels of hardwoods and VisorWood for lower modification levels of pine. Commercial production according to the Kebony process has been running since August 2000, mainly for flooring. A small Kebony production plant is now in operation in Lithuania. A larger Kebony/VisorWood production plant started up in September 2003 in Porsgrunn, Norway. Several new plants operating according to the VisorWood process, each with an annual capacity of 10 000 m³ or more, are under construction. The properties of furfurylated wood depend on the retention of grafted/polymerised furfuryl alcohol (PFA) in the wood. At high modification levels (high retention of PFA) the enhancement of a wide variety of properties are achieved: an exceptional hardness increase, exceptional resistance to microbial decay and insect attack, high resistance to chemical degradation, increase in MOR & MOE, and high dimensional stability. At lower modification levels many property enhancements also occur, however to slightly lower extent. Notable are resistance to microbial decay and insect attack, increase in MOR & MOE, and relatively high dimensional stability.
M Westin, S Lande, M Schneider
Development of marine borers research in Sao Paulo State, Brazil
1985 - IRG/WP 4117
This paper describes some field tests which have been carried on marine sites in Sao Paulo State mainly to investigate the natural resistance of Brazilian woods and the occurrence of marine borers. Some laboratory breeding tests which are being developed are also describe
G A C Lopez
Natural Resistance of timbers to marine borer attack. COIPM/IRG CO-OPERATION. Final report concerning panels exposed in the sea at Sekondi, Ghana
1979 - IRG/WP 449
The test was carried out according to Document COIPM/72.044, Revised procedure for the testing of naturally durable timbers against marine borers. The panels of the three species remaining in the test at the end of 1978 were removed and assessed visually. An average rating was given to the panels of each species.
F F K Ampong
Durability of pine modified by 9 different methods
2004 - IRG/WP 04-40288
The decay resistance was studied for pine modified by nine methods of wood modification: 1) Acetylation, 2) Treatment with methylated melamine resin (MMF), 3) Acetylation followed by post-treatment with MMF-resin, 4) Thermal modification, 5) Furfurylation, 6) Maleoylation (using water solution of MG or ethanol solution of maleic anhydride), 7) Succinylation, 8) NMA-modification and 9) modification with reactive linseed oil derivative (UZA), Wood blocks of Scots pine (Pinus sylvestris L.) sapwood were modified in pilot plants. Methods 1-5 were performed by the authors at Chalmers University of Technology or at BFH in Hamburg. Methods 5-9 were part of a European research project (the Chemowood project, FAIR-CT97-3187) and therefore each of these modifications was performed by the project participant responsible for the method. For laboratory testing in TMCs (modified European standard ENV 807) and pure basidiomycete culture bioassays, smaller test specimens were cut from the modified wood blocks. Most of the modification methods were applied on test specimens for marine field testing (EN 275) and some methods to produce mini-stakes for field tests in five Swedish fields. Some modification methods result in modified wood with poor durability, whereas other methods (acetylation, furfurylation and MMF-treatment) seem to provide excellent resistance to microbial decay.
M Westin, A O Rapp, T Nilsson
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
An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong
Laboratory tests on natural resistance to Cryptotermes brevis (Walker) attack of native hardwoods for crossarms production
1985 - IRG/WP 1266
Eletropaulo (Eletricidade de Sao Paulo S/A) and IPT (Instituto de Pesquisas Tecnologicas do Estado de Sao Paulo S/A) are carrying on a study to evaluate wood species for crossarms in replacement of Aspidosperma polyneuron - Apocynaceae (Peroba-rosa) traditionally used for this purpose. Nineteen Amazon wood species were elected, with physical and mechanical properties equal or better than those presented by Peroba-rosa. Biological tests with these woods and physical tests of crossarms were carried out. Here is presented the results of the resistance test to Cryptotermes brevis attack.
M D Canedo, A T De Lelis
The effect of sapwood on the rate of deterioration of fence posts
1986 - IRG/WP 1277
In order to evaluate the effect of the presence of sapwood on the rate of deterioration of fence posts, 30 specimens with and without sapwood of Eucalyptus citriodora, Eucalyptus paniculata, Eucalyptus saligna and Eucalyptus tereticornis were exposed in three test sites in the State of São Paulo, Brazil. The results of the inspection carried out in 1985, after 5 years of exposure, are reported in the present paper.
M S Cavalcante, G A C Lopez, E S F Mucci, R G Montagna
Wood in concrete. Summary of discussion at IRG 14, Surfers Paradise, Australia
1984 - IRG/WP 3264
The performance of untreated and preservative treated wood when placed in direct contact with concrete was considered in a discussion session at IRG 14. While published reports in this area are scarce, research is in progress internationally and a variety of practices are currently available to minimize any additional hazard posed by contact with concrete. This report summarizes the points raised at the IRG discussion.
R J Murphy
Report of the meetings of the Refractory Timbers Sub-group, Rotorua, New Zealand, 15 & 17 May 1990
1990 - IRG/WP 3637
R J Murphy
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
An in-ground natural durability field test of Australian timbers and exotic reference species. Part 2: Progress report after approximately 13 years' exposure
1983 - IRG/WP 1189
The condition of heartwood specimens of Australian and exotic timber species after approximately 13 years' in-ground exposure is given. Four of the 5 test sites have a termite hazard in addition to the hazard from a range of decay fungi. Values for specimen life are given only where all replicates of a timber species have become unserviceable. Results give evidence leading to doubt about the accuracy of the tentative durability ratings previously ascribed to at least some of the species under test.
J D Thornton, G C Johnson, I W Saunders
Methodology challenges in developing a transfer of natural durability from sawmill residues, illustrated by experiences with white cypress (Callitris glaucophylla)
2000 - IRG/WP 00-20203
The transfer of durability-conferring extractives from durable to non-durable wood has been accomplished often, but usually as an educational exercise rather than as a commercially oriented process. In the latter environment, many factors previously overlooked become vitally important. How to study them, in the absence of well-developed methodology and given the shorter timeframes being demanded by industry research funding organisations, presents real challenges. These challenges will be illustrated by experiences with the development of such a process for the 'waste' durability components of white cypress. Factors to be considered include: identification of active components; quantification of their individual and collective activities against target organisms; optimisation of source material handling, storage and extraction techniques; extract standardisation and batch-to-batch reproducibility; compatible yet cost-effective carriers for the actives into treated wood; effects on durability and other wood properties such as strength and handling safety; regulatory obstacles including acceptance into wood preservation standards; and quality control methods for penetration and retention of the treated product.
M J Kennedy, M A Powell
A survey to assess the current and future usage of timber in British port structures
1998 - IRG/WP 98-10247
Port engineers responsible for 30 British ports were surveyed by questionnaire or interview to establish current and prospective usage of timber in those ports. The ports surveyed account for about 25% of total cargo handled annually in Britain and being located all around the British mainland, were considered to form a representative sample. The survey identified the hardwoods and softwoods in use for various applications in port structures, the criteria for selecting materials for these structures, the materials considered most suitable for piles and fenders and the types of preservative specified. Additional data was collected on the current condition of structures, incidence of marine borers, experience and training of port engineers and their attitude towards timber.
G S Sawyer, S E M Plaster
Draft Business Plan of CEN/TC 38 - Durability of wood and wood-based products - Introduction
2000 - IRG/WP 00-20207
CEN Technical Committees and Business Planning. The extension of formal business planning to CEN Technical Committees (CEN/TCs) is an important measure which forms part of a major review of business processes (known as 'Optimization'). The aim is to align the CEN work programme with expressed market needs and to ensure the adequate resourcing of projects through their development stages in the CEN/TCs. Your role in the implementation of the Business Planning concept will contribute significantly to the overall effectiveness of European standardization. We express our sincere appreciation and thanks for your time in reviewing this Business Plan.