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Introduction to a field demonstration of various instruments and methods for the detection of defects in poles
1984 - IRG/WP 2228
H Friis-Hansen

Principles and procedure of the planeing test
1981 - IRG/WP 2162
Small end-sealed samples of pine-sapwood (1.5 x 2.5 x 5 cm³) are treated by brushing and afterwards different parts of the treated surface are removed. The remaining part of the sample is tested against either insects or fungi. If no attack occurs sufficient amounts of biocides have been penetrated at least beyond the zone which has been removed. In spite of some problems the test seems the only suitable method, to evaluate organic solvent preservatives, mainly those containing resins, for simple treating methods.
H Willeitner, M Gersonde

Vertical distribution of fouling and wood-boring organisms in the Trondheimsfjord (Western Norway)
1981 - IRG/WP 467
Results of a detailed study on the vertical distribution of fouling and wood-boring organisms of Trondheimsfjord at an interval of 3 m from intertidal level to a depth of 30 m, has been presented, based on data collected from two series of panels, exposed from 15 March 1977 to 15 July 1977 (Series I) and from 22 July 1977 to 13 March 1978 (Series II). The intensity of fouling generally decreased with increasing depth. Quantitatively, fouling was heavy on panels of Series I more than on Series II, although species-wise it was more heterogenous on panels of Series II. The bulk of the fouling was constituted by Balanus crenatus, Laomedia sp., Mytilus sp., Modiolus sp. and Hiatella arctica. Incidence of borers and the resultant destruction of timber were heavier on panels of Series II than on those of Series I. The influence of the period of exposure on the above pattern of infestation by foulers and borers has been discussed. Psiloteredo megotara concentrated at the upper levels up to a depth of 15 m, with more settlement between 3 m to 9 m depth. Although Xylophaga dorsalis was present on panels from 3 m to 30 m depth, their intensity abruptly changed from 9 m onwards and continued to increase with increasing depth, with a maximum number near the mud level at 30 m. Attack of Limnoria lignorum also was heavy at the mud level. On the same panel, while Psiloteredo megotara preferred to settle in more numbers on the lower surface, Xylophaga dorsalis did so on the upper silted surface. The importance of such selective vertical incidence of different borers and their co-operation in the destructive activity have been stressed from the point of wood destruction in the Tronheimsfjord. The rate of growth of Balanus crenatus, Laomedia sp., Psiloteredo megotara, Xylophaga dorsalis, and Xylophaga praestans in relation to depth has been presented. For Balanus crenatus rate of growth decreased with increasing depth, while for Laomedia the same increas with depth up to 12 m and declined thereafter. In accordance with its depth preference, Psiloteredo megotara registered faster growth between 3 to 15 m depth. In the case of Xylophaga dorsalis, the size of the shell valve and burrow increased with increasing depth up to 24 to 27 m and then showed a slight decline at 30 m. Factors influencing the growth-rate at different levels have been discussed. The results on the vertical zonation and rate of growth of the wood-infesting organisms encountered, have been compared with relevant literature published earlier.
L N Santhakumaran

Annotated check-list of the Limnoriidae
1990 - IRG/WP 4160
The crustacean isopod family Limnoriidae comprises 51 species of marine borers. A list of species is provided, together with notes on the species known distributions, depth ranges, and habitats. There is also a brief account of the phylogeny of the group.
L J Cookson

Effect of incising depth and density on treatment of Douglas fir, hem fir and spruce-pine-fir lumber with CCA, ACZA or ACQ
1997 - IRG/WP 97-40093
Incising markedly improves both the depth and uniformity of preservative treatment of refractory wood species, but there are few studies directly comparing the effects of incising depth and density on penetration and retention of commonly used waterborne preservatives in wood species from the western United States. The effects of two incision densities (7300 and 8900 incisions/square meter) at two depths (5 and 7 mm) were investigated using two strength classes of Douglas fir, hem fir and spruce-pine-fir lumber. In general, grade or strength class had no significant effect on treatability. Treatability markedly improved with increasing incision depth, while increased incision density produced less tangible results. Ammonia-based treatments were associated with deeper penetration reflecting the ability of the heat and/or ammonia to improve preservative penetration. Further studies are underway to evaluate the effects of incising and subsequent preservative treatment on strength properties.
M Anderson, J J Morrell, J E Winandy

Comparative moisture uptake of Douglas fir and radiata pine structural lumber when exposed to rain wetting as an indicator of relative decay resistance
2004 - IRG/WP 04-20285
Trials were undertaken to determine the relative resistance of radiata pine and Douglas-fir to wetting when exposed to the weather. Douglas-fir samples were obtained from one Central North Island and three South Island sources and had a heartwood/sapwood mix typical for each resource. Radiata pine sapwood and heartwood samples were obtained from a Central North Island source. Material was exposed to the weather as horizontal studs in the first trial, and as horizontal and vertical studs in the second trial. The first trial ran over later winter from 29 July to 22 September 2003; the second, and more comprehensive investigation, from 22 October to 17 December 2003. In the first trial, after seven days exposure, radiata pine reached a moisture content which would sustain decay (~27% mc), and remained well above that moisture content for the remaining 48 days of the trial. However, the maximum moisture content attained by Douglas-fir throughout the trial was only 21.8 % mc. In the second trial, radiata pine sapwood rapidly attained a moisture content conducive to decay, and Douglas-fir did not. Because of the warmer and sunnier weather, fluctuations in moisture content were more pronounced than in the winter trial. Samples exposed horizontally attained higher moisture contents than those exposed vertically, irrespective of wood species or relative heartwood/sapwood content. It is concluded that Douglas-fir timber shows significant positive differences from radiata pine in terms of susceptibility to moisture uptake. This trial confirmed the ‘refractory’ reputation of Douglas-fir, and the ‘absorbent’ reputation of radiata pine. At a practical level, Douglas-fir heartwood and sapwood can be regarded as equally impermeable, and independent of where in New Zealand it was grown.
M E Hedley, G Durbin, L Wichmann-Hansen, L Knowles

Observations on the morphology, ecology and biology of Xylophaga dorsalis (Turton) (Mollusca: Xylophagainae) in the Trondheimsfjord (Western Norway)
1981 - IRG/WP 475
The paper deals with various aspects of the systematics, ecology and biology of the little known pholad wood-borer, Xylophaga dorsalis (Turton) of the Trondheimsfjord (Western Norway). Diagnostic characters of the species have been given based on examination of fresh living specimens and accommodating the several morphological variations. A key to the identification of Norwegian species of Xylophaga is also included.
L N Santhakumaran

Depth of foraging of subterranean termites in tropical Australia
1996 - IRG/WP 96-10141
Stakes of radiata pine (Pinus radiata D.Don) of varying lengths to 800 mm were inserted vertically in the soil with all but their lower 100 mm sheathed in a capped UPVC tube representing a physical barrier to termites. In one series of trials, termites were encouraged to aggregate at the upper ends of the tubes, in order to determine whether they would descend to the lower end of the barrier. In a second trial stakes were relatively isolated and inserted with minimum soil disturbance. In both trials all barrier lengths, namely 300, 400, 500, 600 & 700 mm failed to prevent termite attack on the lower ends of the stakes. Mastotermes darwiniensis Froggatt, Coptotermes acinaciformis (Froggatt), Schedorhinotermes breinli (Hill), Schedorhinotermes actuosus (Hill), Heterotermes validus Hill and Heterotermes vagus (Hill) all attacked stakes at a depth between 700 & 800 mm. This factor should be taken into account when considering the design of protective barriers, whether chemical or physical, for buildings or other timber in service.
L R Miller, M Hoschke, M Neal

Method to determine the depth of penetration of the biologically active components of wood preservatives
1978 - IRG/WP 2108
A time-saving method for determining the depth of penetration of the biologically active components of wood preservatives is described. The test specimens were obtained by cutting thin slices from the wood either parallel or perpendicular to the treated surface. The slices were then exposed to fungal attack. A good correlation was found between the test results obtained by the modified German Standard method (plane-off test), published by BECKER and STARFINGER (1971).
H-P Sutter

Microscopic FT-IR depth profiling study of photo-induced degradation in wood
2001 - IRG/WP 01-20229
FT-IR microspectroscopy was used to monitor the changes in the chemical composition at various depths from the photo-irradiated surface of sugi (Cryptomeria japonica D. Don) sapwood. The radially cut wood face was exposed to artificial solar radiation from a xenon light source at 375 Wm-2 (in a 300 - 700 nm spectral range) for up to 600 h. The IR depth profiling spectra showed that the artificial sunlight caused most significant chemical changes in the outermost wood layer, while some chemical effects penetrated the wood as far as 600 m from the surface to form a thick degraded layer. The results of monitoring some photosensitive absorption bands for various exposure times revealed that there was a continuous growth of the degraded layer whose growth rate became increasingly restricted with exposure time. These results may explain why various depths or thicknesses have been reported for this phenomenon.
Y Kataoka, M Kiguchi.

Penetration Depth of Borates in Historic Wooden Structures in Virginia City Montana
2008 - IRG/WP 08-30475
Virginia City, Montana contains some of the best preserved examples of gold boom construction in the United States. Unfortunately, even the dry climate and fortuitous lack of fire have not prevented decay from claiming parts of the historic fabric. This project aims to determine if borates should be integrated into the preservation plan of the Montana Heritage Commission. Solutions of disodium octaborate tetrahydrate (DOT) were tested in both new and historic lodgepole pine (Pinus contorta) in a fashion that mimics remedial treatments likely carried out in the field. DOT (available commercially as Tim-Bor Professional from Rio Tinto Mineral or Nisus Corporation) and glycol borate (DOT in a proprietary mixture of glycols including polyethylene glycol, available commercially as Bora-Care® from Nisus Corporation) solutions were tested.
A A Turner

Natural Durability of Fence Poles from Fourteen Semi-Arid Land Species after Six-Month Exposition
2010 - IRG/WP 10-10724
A sample of thirty fence poles from each of fourteen tree native species from Northeast Mexico were tested in ground contact in a wood-cemetery area located in Linares, Nuevo Leon, Mexico. The samples were submitted to six treatments (control, debarked, chemical treated, used cooking oil, thermal and creosote) and randomly distributed in five blocks. The effectiveness of using a bark gauge tool “depth method” for decay determination was compared to visual method. Analysis of variance (ANOVA) for comparing natural durability between species, treatments, and monitoring system were determined by SAS (Statistical Analysis Software). Results showed that Hellieta parvifolia and Hevardia pallens were the most resistant on ground condition. Regarding to used cooking oil treatment (2.4 mm) it was found as the best for reducing wood decay followed by chemical method (2.4 mm) and finally, the debarked treatment (2.4). The higher decay rates were presented by thermal (2.8 mm) and control treatments (2.7 mm).
A Carrillo, F Garza, V Bustamante, S Sandoval, H Villalón

Methods for Studying Penetration Depth of Wood Protection Products
2010 - IRG/WP 10-20432
EN 152 is an accepted standard in Europe for measuring how deep a wood protection product penetrates into the surface of treated pine wood. The method has provided consumers with a wide assortment of products that meet the specifications outlined in the standard. Because the test takes 8 or more months to carry out, artificial ageing procedures have evolved in order to standardize and speed up the procedure. Small changes in a formulation will often change a products physical parameters and especially its ability to penetrate into wood. It is therefore desirable to develop a method that can measure changes in a product’s penetrability quickly and accurately. A method is described where wood cores are drilled from treated wood, then sliced in 100 µm thick discs. Discs are then placed on nutrient agar plates seeded with conidia from Aspergillus niger. Plates are incubated for 24 hours and zones of inhibition are measured. It is believed that if a fungus is growing on the disc the biocide level will not exceed that of the fungus minimum inhibition concentration (MIC). In water based acrylic systems penetration depths are often less than one mm and it can impact the performance of a product if that changes. The procedure described in this study can show if penetration of a preservative product has been increased or reduced in as little as 24 hours.
K Hansen, L Sites, D D Nicholas

Effectiveness of Copper Indicators in Treated Wood Exposed to Copper Tolerant Fungi
2014 - IRG/WP 14-20554
Wood treated with a copper based wood preservative will typically turn a green color. While the depth of copper penetration can be readily discerned from the green color of the copper it is standard practice in research and commercial treating plants to make use of a color reagent such as Chrome Azurol S, Rubeanic acid or PAN indicator to reveal the penetration more clearly. When copper treated wood is exposed to copper tolerant fungi discoloration of the original green color can occur. Reactivity of the treated wood with the color reagents can also be impaired. In this paper, the effectiveness of copper color indicators in detecting copper in wood attacked by copper tolerant brown rot fungi at early and late stages of decay was evaluated. Neither Chrome Azurol S nor PAN indicator could detect copper in the area where incipient and severe decay took place, even when chemical analysis showed significant levels of copper in these areas. Rubeanic acid was the only indicator which provided positive identification of copper in these samples. An FTIR study demonstrated that the loss of green color in copper treated wood by copper tolerant fungal attack is closely related to the formation of copper oxalate. The finding supports the theory that copper oxalate detoxifies copper and acts as a precursor for decay since a significant amount of copper oxalate was found in the area with discoloration but no visual decay, as well as in the area with severe decay. The results from this study suggest that the ineffectiveness of Chrome Azurol S and PAN indicators may be due to their inability to replace oxalate ion to form the colored complex with copper.
L Jin, K Brown, A Zahora, K Archer

Influence of pressure phase impregnation time on the uptake and distribution of wood preservatives in Scots pine material of diverse treatability
2016 - IRG/WP 16-40752
In spite of the general opinion that Scots pine sapwood is easy to impregnate considerable variations in treatability are reported. In order to study impregnation results of diverse Scots pine sapwood treated with increasing process times, Scots pine sapwood from two different predefined treatability groups was impregnated. A copper solution was used as impregnation agent in ten different vacuum pressure schedules. Pressure times increased from 15 min to 520 min. The results of this study confirm considerable variations in the treatability of Scots pine sapwood. Differences between easy to impregnate and refractory sample sets are visible for the different impregnation schedules. The impregnation results however depend on the indicator of treatment quality applied. The refractory sample set reaches higher solution uptakes after 180 min of pressure whereas the easy to impregnate sample set has a better penetration of the wood matrix for most of the impregnation schedules. Differences in the results are visible when comparing indicators of treatment quality based on solution uptake, ratio of filling and impregnation depth. The gravimetric method (uptake) can give a false impression of the impregnation result. It is important to be aware of these differences in treatability of the material and between different indicators of treatment quality. The results can be important for the impregnation industry as they show that by sorting for easy to impregnate material, process times could be significantly reduced and simultaneously lead to more homogeneous impregnation results and smaller within batch variations.
K Zimmer, B Kerfriden

Response of Terminalia mantaly H. Perrier wood to beetles tunneling in Southern Nigeria
2018 - IRG/WP 18-10918
Terminalia mantaly (TM), is extremely susceptible to beetles attack, as evidenced by the many scars and/or tunnels on nearly all the trees in the Southern Nigeria. However, information on the responses of wood to insects tunnelling is poorly known for tropical species. To examine the response of TM stem wood to beetles tunnelling in the University of Port Harcourt, we scheduled field observational visitations and measurements daily once. The tunnelling beetles were identified as Apate terebrans. All the trees responded to tunnelling through sequential exudations of resin and gum for mean duration of 47.25±8.25 and 27.42±4.83 days, respectively. Resin significantly contained higher concentrations of compound phenol ˃ tannin ˃ terpenoids ˃ alkaloids ˃ saponin than gum while gum significantly contained elevated contents of element chloride ˃ calcium ˃ Iron ˃ lead ˃ zinc compared to resin, indicating their specificity roles in the healing scenario of TM wood to A. terebrans tunnelling. Healing period was largely positively correlated with tunnel depth (r = 0.990, p<0.000), reflecting the opportunity for greater biochemical responses during the healing process. The results suggest that the resilience of TM against insects attack is highly possible, but the possibility for further degradations by secondary agents is high.
G A Adedeji, U Zakka, A A Aiyeloja, A I Ochuba