Your search resulted in 52 documents. Displaying 25 entries per page.
Bending strength of heat-treated spruce and pine timber
2002 - IRG/WP 02-40242
Heat-treatment of spruce (Picea abies) and pine (Pinus sylvestris) beams (45 x 145 mm) gave a reduction in bending strength of approximately 50%. The bending stiffness (modulus of elasticity) only decreased by 3.5%. Tests were carried out according to EN 408. Another effect of the heat-treatment was increased variation in bending strength. The 5th percentile value of the bending strength, the so called characteristic value, decreased by 66% for spruce and by 55% for pine after heat-treatment. The study consisted of 200 spruce beams and 200 pine beams of Swedish origin. Half of the material was heat-treated and the other half was used as controls. The heat-treatment was carried out in a steam chamber in Finland at a maximum temperature of 220°C. The level of treatment was assumed suitable for above ground end uses. When storing the material in a climate that was approximately 20°C/65% relative humidity the heat-treated material reached an equilibrium moisture content of 3-3.5%. For the untreated material corresponding figure was 12-12.5%. The dry density for the heat-treated material decreased by approximately 7.5% compared to the untreated material.
C Bengtsson, J Jermer, F Brem
Comparison of cubic and plug samples for preparation and data assembly in permeability study
2000 - IRG/WP 00-20197
In order to determine if plug experimental samples (PES: 30 x 15 mm2 diameter) could be used for inspection of wood permeability characteristics, radial and longitudinal flow directions were prepared according to either PES or cubic experimental samples (CES: 100 x 20 x 20 mm3) from the sapwood zone of Sitka spruce and treated by tanalith-C according to full-cell process. Results from the two preparation techniques agreed in the test to determine the mean percentage of void volume filled by liquid both radially and longitudinally, while the preparation process (i.e. machining, sealing, etc.) of the experimental samples and the period of the data collection was quite longer in CES than that for PES in either flow direction.
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
Fumigation as a remedial treatment: A review of North American literature
1983 - IRG/WP 3253
The development of the use of fumigants for eliminating decay in timber and roundwood in North America is reviewed. Initial experiments on oak wilt identified volatile chemicals which eradicated decay in roundwood. Subsequently, extensive experimentation on Douglas-fir poles in service showed that treatment with chloropicrin eliminated internal decay for more than ten years. Vorlex was also quite effective, but Vapam appeared to be much less effective, with decay fungi becoming re-established within ten years of treatment. Studies on other wood species indicated that fumigation could be successfully used to treat resistant species such as western red cedar. Fumigation of glulaminated beams and large timbers with chloropicrin, showed that internal decay could also be eliminated in these products, although wrapping the beam in polyethylene was beneficial for optimization of the treatment. Bioassay techniques have been reported for successful monitoring of fumigant vapor concentrations in treated poles.
J N R Ruddick
Analysing the characteristic role of moisture content for drying and fluid flow in Sitka spruce. - Part 1: The drying process of sapwood and heartwood of two different thickness of Sitka spruce using a kiln. - Part 2: Effects of moisture content on longitudinal permeability of Sitka spruce in vertical variation of the tree
2000 - IRG/WP 00-40173
The characteristic role of the moisture content in Sitka spruce (Picea sitchensis (Bong.) Carr.) that grown in the United Kingdom was examined by this study on the basis of (1) the reduction of moisture content in two different thickness of sapwood and heartwood by kiln drying process, and (2) the effects of moisture content to the longitudinal void volume filled of tanalith-C by the full-cell process from base (1 m) to apex (3 m) of the tree in sapwood zone. Accordingly, conclusions on indication of the drying process of sapwood and heartwood, and vertical variation of longitudinal flow with effects of moisture were listed separately: (1) Comparison of Drying Characteristic of Sapwood and Heartwood: The two different thickness (300x30x30 mm3 and 300x20x20 mm3) of sapwood and heartwood of Sitka spruce was dried using the suggested drying schedule in kiln. The reduction of moisture was schematically diagrammed according to sapwood and heartwood stakes. The reduction of moisture followed the same downward trend that sapwood (S) loses more moisture than heartwood (H) although the small stakes of S and H lost moisture rapidly compared with the large ones. (2) Vertical Variation of Moisture Content and Longitudinal Permeability: The 90 kiln dried defect free sapwood stakes (150x25x25 mm3) of Sitka spruce was taken from base to apex of the trees at 1, 2 and 3 m above ground level. After having the determination of moisture content in each experimental stake, the treatment was carried out by the full-cell process with CCA preservative (Tanalith-C) using a model pressure treatment plant. Significant differences observed among the tree heights from 1 to 3 m showing that slightly increases of moisture content from base to apex and conversely decreases of longitudinal void volume filled by preservative fluid.
An effective preservative treatment of borak bamboo (Bambusa balcoona Roxb.)
1996 - IRG/WP 96-40070
Adequate penetration and retention of CCA and CCB has been obtained in predried Borak Bamboo (Bambusa balcooa Roxb.), aboundantly grown in Bangladesh, with Full Cell Pressure Process. The treated bamboo can be used as building materials, the sufficient treatability ensured its long term best utilization at ground contact and indoors. Which will keep the environmental & socio economical conditions of Bangladesh more viable and normal.
A K Lahiry, S Begum, G N M Ilias, M A Matin Sheikh, M A B Fakir, M I Hossain
A deflection test for monitoring decay in miniature beams
1986 - IRG/WP 2269
A laboratory apparatus for assessing decay in small stakes is described. It involves the measurement of deflection in a static bending apparatus using a displacement transducer linked to a microcomputer. Measurements are non-destructive, rapid, accurate and automatic and decay can be assessed repeatedly over long time periods.
S M Gray
Copper naphthenate-treated Southern Pine pole stubs in field exposure. -Part 2: Chemical characterization of full size pole stubs 12 years after treatment
2000 - IRG/WP 00-30246
This study examines the influence of pre-treatment and post-treatment steaming on the character and physio-chemical nature of copper naphthenate in hydrocarbon solvent treated pine in larger, pole diameter, pole stub-length samples. This work is the continuation of two projects that began almost a decade ago. Previous reports indicated that certain morphological changes might occur in small laboratory steamed samples of copper naphthenate treated southern pine. Toluene-methanol extraction, UV-Vis spectroscopy, X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) were used to investigate the nature and properties of the copper naphthenate present in the wood after 12 years of exposure. The formation of solid cuprous oxide occurred regardless of pre- or post-steaming conditioning.
H M Barnes, D P Kamdem, M H Freeman
The effects of density on vertical variation of permeability of Sitka spruce within tree
2000 - IRG/WP 00-40156
Tree improvement of Sitka spruce is a combination of silviculture and tree breeding aimed at producing higher quality products including increased growth rate and timber yield, and wood density. It is useful to know annual ring structure and density distribution when studying the quality of wood, grading it, or determining how the wood structure affects residual flow in softwoods. Since density is a factor under genetic control, the study in this article details the effects of density on longitudinal and radial permeability of Sitka spruce from base to apex. Comparison of overall means of both longitudinal and radial void volume filled (%) suggest that longitudinal permeabilities were almost the mirror image of those for the radial permeability along the tree trunk.
Diffusion of bifluorides and borates from preservative rods in laminated beams
1991 - IRG/WP 3644
Laminated beams from spruce, pine and larch were treated with two preservative rods, based on bifluorides and octaborate respectively. After 3 and 6 months placed in different climates (65% r.h., 100% r.h., water) the diffusion of the active ingredient was measured. After the 6 months period, the diffusion of the bifluorides was, in all species, ca. 5 times larger than the diffusion from octaborate rods. The bifluorides were not hindered by the glue-lines. The diffusion of the borate was poor, mainly perpendicular to the grain and was hindered by the glue-line.
A laboratory evaluation of the susceptibility to biological attack of glued laminated pine timber
1991 - IRG/WP 2387
In the scope of a research programme concerning the use of maritime pine (Pinus pinaster) to produce glued laminated timber structures in Portugal, the natural durability of this material was checked by using laboratory test methods. An European standard, EN 113, was used to test durability against basidiomycetes and a test method developed at LNEC for termites was adapted for this purpose. From the results obtained, it seems that the existence of glue layers does not influence the natural durability of the material under basidiomycetes attack. As for termites the method used indicates that they are unable to cross the glue layers though this effect would hardly be of importance for practical uses.
L Nunes, H Cruz
Leaching of copper, chromium and arsenic from CCA-treated slash pine heartwood
1994 - IRG/WP 94-50020
Drying green slash pine with any of three high temperature drying schedules produced a product in which both the sapwood and the heartwood could be penetrated with CCA using a modified Bethell treatment schedule. Required H3 retentions were achieved in both sapwood and heartwood, from 200 litres per m³ charge uptake. Post-treatment fixation/drying was accomplished by three different regimes, including an accelerated fixation. Although acceptable preservative penetration and retention was achieved in the heartwood, arsenic fixation (as determined by both AWPA procedure E11-87 and U.S. EPA TCLP procedure) was inferior to that attained in the sapwood. TCLP leachates from 1 cm³ heartwood blocks contained up to 4.5 mg/l arsenic, very close to the maximum value (5.0 mg/l) currently permitted in Australia for arsenic waste disposal. Though there are clear advantages in achieving heartwood penetration, caution must be exercised to ensure that this step does not compromise the accepability of the product. No process modification could be accepted if it introduced possibilities of exceeding safe disposal limits for sawdust and offcuts, or building site contamination.
M J Kennedy, G Palmer
A behaviour of CCA penetration of fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications
2006 - IRG/WP 06-40346
A behaviour of CCA penetration of Bornmulleriana fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications was illustrated for the main flow directions by the experimental pictures.
I Usta, R Despot, M Hasan
Preservation of two Indonesian timber species for marine environment purposes
1994 - IRG/WP 94-10079
This paper deal with the experiment of CCA full cell processed two non-durable Indonesian species for placed in the marine environment. 80 samples of 5 x 5 x 60 cm³ dried durian (Durio zibethinus) and mahogany (Swietenia mahagony) timber were CCA-full cell processed using 4 combination treatment of: without steaming; one hour steaming; 3% and 5% CCA solution concentration. 40 samples of them were field tested in the sea water in Rambut island beach near by Jakarta. The results shows that mahogany very difficult to treat and not recommended to be placed in marine environment, while CCA retention in durian timber could reach 29.91 kg/m³ and meet the requirement of retention for timber to be placed in marine environment. After two month field test in sea water full cell processed drian with 5% CCA solutin concentration could prevent marine borers attack.
P Permadi, I M Padlinurjaji, F Rasmita
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
Wood protection processes in the Asean countries
1994 - IRG/WP 94-40034
This paper presents the wood processing practices in the Asean countries composing Indonesia, Malaysia, Philippines, Singapore, and Thailand except Brunei. The development of wood preservation industry in these countries started as early as 1922 to 1960. As in other industrial countries, treatment pressure with creosote of utility poles, railway sleepers, and marine pilings are the prime commodities that require long term protection. The introduction of water-borne preservatives covered the treatment of sawn timber and other lignocellulosic materials. It covers the historical background and development of the industry in each country, treatment processes both pressure and non-pressure of commodities e.g. power poles, railway sleepers, marine pilings, housing components, furniture, and other lignocellulosic materials requiring protection against biological deterioration. Technical problems are common and varied due to different treatment standard specifications and preservatives specially water-borne types. The pollution aspect of preservating plants and the prohibition and control of some wood preservatives is a growing concern of the environmentalists. Wood preservation in the Asean countries will stay on and geared towards the treatment of industrial tree plantations, rubberwood, palms and bamboos.
F R Siriban
A study on the pressure impregnation of Eucalyptus globulus fence posts with CCA preservatives. Part 1
1988 - IRG/WP 3470
This paper describes the impregnation with CCA preservatives by full-cell process of Eucalyptus globulus fence-posts. Several treatments were made for different times of initial vacuum and treating pressure, with fence-posts from two coppice plantations (1st and 2nd rotations), assembled into three diameter classes: small, medium, large. The results concerning the absorption and lateral penetration of the product reveal that impregnation of Eucalyptus globulus though difficult is often possible. The highest average values were recorded in the small diameters, yet the standard deviation in all three classes is quite remarkable. Moreover fence-posts from the 1st rotation stand show a better behaviour with the treatment. There seems to be no significant correlation between absorption and initial vacuum or treating pressure times.
D De Sousa Castro Reimão, L Nunes
Investigation of temperature effect on fixation of Celcure preservative (ACC) in beech (Fagus orientalis)
2001 - IRG/WP 01-40200
In this research, the fixation speed of Celcure 2% (ACC) preservative salt, under temperature of 17°C, 27°C and 50°C, on intact and stained wood specimens of beech was investigated. For this purpose, blocks of wood with 5x5x7 cm dimensions were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. For measuring the percentage of fixation through time, the specimens were extracted by using hydraulic pressure equipment, under 69 Mpa pressure. The pH of extraction was measured with the method of diphenyl Carbazid and by using spectrophotometer. This measurement was done continuously and the amount of 6- valence chromium concentration present in the extract was compared with the amount of chromium concentration in the primary solution and then the percentage of fixation was calculated. The results showed that the decrease in 6-valence chromium is accompanied with increase of pH, this is due to absorption of positive hydrogen ion by 6-valence chromium for reduction to 3-valence chromium and also ion-exchange of active components with wood during the primary phase of fixation. Also, the time necessary for reaching complete fixation in intact and stained wood in the fixation temperature conditions of 17, 27 and 50°C were 1075, 501, 109 hours, respectively. In general, the results showed that temperature has effective role in accelerating of fixation process and in this respect, intact and stained wood did not show significant statistical difference.
A Karimi, M Ghorbani
Essais de collage de bois traités pour la réalisation d'éléments de charpente lamellées. (+ abstract dated September 1971, Influence du traitement de préservation sur le collage d'éléments de charpente lamellés collés et efficacité vis-a-vis de larves néonates)
1971 - IRG/WP 203
Le but du travail est de vérifier les propriétés générales d'une poutre lamellée collée après traitement des éléments la composant au moyen de formulations insecticides et fongicides commerciales à solvant clair dans les conditions les plus usuelles de fabrication. Les essences utilisées ont été: Epicéa - Pin sylvestre - Sapin de Douglas en planches rabotées de 80 cm de long, 14 cm de large et 20 mm d'é-paisseur, à environ 12% d'humidité, collées après traitement avec une colle de type résorcine - formol du commerce à raison de 6 éléments pour former une poutre expérimentale. Les produits de traitement ont été au nombre de 4, commercialisés -couramment utilisés sur le marché français. Ces produits seront appelés A - B - C - D. Ils appartiennent tous au type organochloré en solution dans un solvant organique, les adjuvants et solvants pouvant être différents. En général, les planches utilisées étaient débitées sur faux-quartier et comportaient essentiellement du bois parfait, la proportion d'aubier en bord état souvent peu importante. Une première mesure sommaire de l'absorption de chaque planche en produit de préservation a été effectuée par pesée. Les essais suivants ont été poursuivis après collage: Résistance à la délamination - Résistance de cisaillement en compression et pourcentage d'adhérence. Les essais biologiques ont porté sur la mise en présence des zones externes des poutres (zones aubieuses pour les essences à aubier distinct et attaquable) avec des larves néonates de Capricorne des Maisons. Les premiers résultats dépouillés permettent de penser qu'aux faibles doses utilisées les propriétés mécaniques des poutres restent satisfaisantes. Après observation du comportement des larves néonates, des dosages chimiques vont être effectués afin d'établir le seuil d'efficacité des quatre produits.
The full guideline for the “double layer test method” - A field test method for determining the durability of wood out of ground
2004 - IRG/WP 04-20290
This guideline describes a test method for wood to be exposed to the weather out of ground contact. The main objective of the method is to evaluate the durability of wood in above ground exposure as shifted overlaid stakes, which form the so called double layer. The method is applicable to the testing of untreated, treated and modified wood. Initially it was developed and found to be most useful for testing of natural durability. As a simple and effective test method, it spread quite fast. Up to now more than 30 double layer tests are running in different countries of the world. The inventors of the double layer test were asked to come up with a full and precise guideline for this test methodology to enable interested scientist making use of this test method. Therefore this IRG- document was written as an instruction for those who would like to perform this test.
A O Rapp, U Augusta
Effect of treating process on efficacy of CCA in a laboratory decay test
1990 - IRG/WP 3628
Test samples of Pinus radiata sapwood measuring 40x40x500 mm³ were treated with a range of concentrations of the copper-chrome-arsenate (CCA) formulation "Tanalith C" using Rueping (empty cell), Lowry (empty cell) and Bethell (full cell) treatment processes. Samples were then reduced to 40x40x7 mm³ test blocks and exposed to the decay fungus Coniophora puteana using an agar/block technique. Replicate blocks were analysed for preservative components. Regression analyses of percentage weight losses of test blocks against total Cu+Cr+As retentions (TAE) showed differences in efficacy of the preservative when applied by the three different processes, the order of effectiveness being Bethell > Lowry > Rueping. Two hypotheses are proposed to explain the results: (1) Disproportionation within the wood of preservative salts when applied by empty cell processes, (2) Differences in distribution of preservative elements following treatment by the three processes.
M E Hedley, K Nasheri, J G Van der Waals
A study on the pressure impregnation of Eucalyptus globulus fence-posts with CCA preservatives. Part 2
1989 - IRG/WP 3514
This paper describes the second part of a study on pressure impregnation of Eucalyptus globulus fence-posts with CCA preservatives presented at the IRG 19th Meeting. Fence-posts of three diameter classes, were treated, considering only one treatment schedule. The results show possibility of vacuum-pressure impregnation of blue gum fence-posts, with diameter less than 9 cm, though mainly by longitudinal penetration, which is usually conditioned by the length of the fence-post.
L Nunes, D De Sousa Castro Reimão
A novel guide for the determination of the physical properties of wood including kiln drying and full-cell preservative treatment
2004 - IRG/WP 04-20298
An ideal flow chart for the sequential experimental determination of a range of physical properties relevant to wood drying and subsequent preservation was designed as a novel guide to assist wood scientists. In this manner, data assembly and experimental processing are shown. This was designed according to experience and published literature. Aspects emphasised in this review were the physical properties which effect the manner of processing particularly in respect to preservative treatment of wood. For this purpose a total of 93 references covering 8 topics (descriptive wood anatomy, physical properties of wood, shrinkage and swelling, wood density, moisture content, fibre saturation point, wood drying (by oven and kiln) and liquid permeability) were reviewed.
I Usta, M D C Hale
Trial to determine a suitable schedule for radial and longitudinal treatment of plug samples by comparison of changes in the fluid retention and the treated area
2001 - IRG/WP 01-40211
A full-cell process was carried out using different treatment schedules for radial and longitudinal samples because of the anisotrophy of flow. When timbers are impregnated with preservatives much better penetrations are obtained via the end grain than laterally (across the grain). Therefore, suitable schedules for radial and longitudinal flow directions were determined in an trial experiment using locally grown Sitka spruce, Queen Charlotte Islands (QCI) provenance, from Beddgelert Forest in North Wales. The full cell experimental schedules used were: initial vacuum 15 minutes at -0.84 bar and various pressure periods that was 5 bar pressure in radial flow direction for 15, 45, and 60 minutes, 3 bar pressure in longitudinal flow direction for 3, 6, and 9 minutes. No final vacuum was applied. After the treatment, the fluid uptake was calculated, and the fluid retention was determined on a whole-block basis. After fixation, plugs were dried and cut longitudinally through the centre and copper penetration was determined by spraying a 1% solution of Chrome Azurol-S on the cut surface and observing the blue colour indicative of copper. The preservative penetration was then measured by image analyser as depth (mm) and as total treated area (%). From the experimental data, it was concluded that the suitable schedules are 5 bar pressure for 45 minutes for the radial flow direction, and 3 bar pressure for 7 minutes for the longitudinal flow direction. Therefore these schedules are suggested to be used to examine the permeability of the different seed origins in both radial and longitudinal flow directions.
Borate diffusion in wood from rods and liquid product. Application to laminated beams
1988 - IRG/WP 3482
In the aim to use borate preservatives (fused rods and boracol) in fields of building construction other than external joineries, tests of diffusion of borate rods and secondary boracol, were carried out on different species of woods exposed to different moisture conditions. Tests were also applied on laminated beams very often subjected to high moisture contents and thus decay of rot fungi. Diffusion was tested in different conditions and in relation, the action of these products was tried with stains and resins for improving strength properties. Diffusion tests on several species of wood confirm the proportionality already observed between moisture content and diffusion of borates in wood for all species. In a short time, test of diffusion on laminated wood showed a good diffusion in two lamella along the glue line leading to another way of boring. There is no problems between these borate products and stains or resins.