IRG Documents Database and Compendium

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Control of termite attack using a trapping method and acoustic emission (AE) monitoring a case study at an electric power plant
1997 - IRG/WP 97-10224
To prevent subterranean termites (Coptotermes formosanus Shiraki and Reticulitermes speratus Kolbe) from invading the buildings of an electric power plant and to control their attack, artificial traps were buried around the buildings. The attack of the termites in and around the traps was monitored by detecting acoustic emissions (AE) generated by the feeding behavior of the workers. The cylindrical artificial traps were 600 mm long and 300 mm in diameter, and consisted of pieces of Japanese red pine surrounded by slender polystyrene foam sticks. Termite inhabitation was observed in eight of the ten traps set, and particularly high levels were found in three traps. The traps were renewed every one or two months. The amount of termites inhabiting the traps decreased drastically after the first renewal, but varied only slightly over the following two and a half years. The amount of termites in the traps increased when the traps were not renewed. Termite activity was significantly restricted by installing artificial traps and no additional serious attacks were found in or around the buildings during the study period. AEs generated by feeding activities were monitored by piezoelectric AE sensors attached to the wooden sticks in the traps or to wooden bait stakes near the trap. The rate of AE events varied according to feeding activity which was associated with the number of termites in the trap and the temperature.
Y Fujii, Y Imamura, E Iwatsubo, S Yamamoto

Influence of different fixation and ageing procedures on the leaching behaviour of copper from selected wood preservatives in laboratory trials
2003 - IRG/WP 03-20264
The paper focuses on the role of different parameters, such as fixation, sample size, wood species, and leaching in internationally standardized ageing procedures for wood preservatives from Europe, Japan and the United States. The leaching protocols used were EN 84, JIS K 1571 and AWPA E11 protocols. The wood species were Scots pine, Sugi and Southern Yellow Pine respectively. Three types of commercially important copper-based wood preservatives were used as model formulations, namely copper/copper-HDO, ammoniacal copper/quat and CCA. The most important factors determining the extent of copper leaching in the different lab trials were the sample size (volume/surface ratio) and the fixation conditions prior to leaching. On the other hand, the wood species and the leaching protocol itself were found to have only minor influence on the copper leaching rate in the test methods included in this study.
J Habicht, D Häntzschel, J Wittenzellner

Field tests out of ground contact in France: Definition of the test procedure and preliminary results after 18 months
1981 - IRG/WP 2161
M Fougerousse

Blue stain in timber in service. Results of co-operative tests to compare different artificial weathering systems 1981-82
1983 - IRG/WP 2193
The paper describes results of the third phase of co-operative laboratory experiments comparing the effects of different artificial weathering systems on chemicals to control blue-stain in service. Atlas, Xenotest and Marr equipments are shown to give essentially the same results for 5 of the 6 chemicals tested.
A F Bravery, D J Dickinson

A comparison between methods for evaluating the water repellency of wood
1989 - IRG/WP 2328
Wood specimens treated with a number of water repellent formulations have been tested for their water repellency according to four laboratory test methods, based on weight increase, swelling and contact angle measurements, in order to assess the degree of agreement between the different methods. Treatments representing formulations with a wide range of water repellent efficiency were tested both initially and after simulated weathering. A ranking of the water repellent treatments shows deviations between the different test methods although the general agreement is relatively good. Contact angle measurements are less appropriate due to a poor repeatability. The development of new standard test methods where the long-term performance or water repellent treated wood is evaluated by a weathering procedure is of great importance.
R Nussbaum

Preventive action against fungal decay: A comparative experiment on the effects of natural and artificial infection of wood by Basidiomycetes
1981 - IRG/WP 2160
M Fougerousse

Electronic noses for detection of rot in wood
1996 - IRG/WP 96-20098
In an ongoing project an electronic nose is being studied and developed for detection of volatile organic compounds (VOC) emitted from wood colonised and decayed by fungi. The electronic nose consists of an array of gas sensors with different selectivity patterns for different groups of volatile organic compounds (VOC). The use of pattern recognition routines implemented by artificial neural networks (ANN) is used to evaluate data from the sensor array. The responses from the sensor array have been correlated to weight loss of and contents of chitin in the decayed wood samples. The results obtained so far indicate that the electronic nose qualitatively can detect significant differences between sound and decayed sapwood of Scots pine (Pinus sylvestris). Preliminary results also indicate that the electronic nose can detect differences between decay types like brown rot (Lentinus lepideus) and soft rot (Phialophora A). Results from a study aiming at investigating the abilities of the electronic nose to quantitatively detect different stages of decay is now being analysed statistically. The influence on the responses from the sensor array due to variation in relative humidity, moisture content of the decayed wood samples and temperature have also been studied.
K Nilsson

Testing wood in ground contact: An artificial soil
1977 - IRG/WP 280
This document is an interim report on the development of the artificial soil medium. It includes some information on the relationship between soil, wood and water which is of relevance in testing.
E F Baines, D J Dickinson, J F Levy

Artificial drying of impregnated wood
1987 - IRG/WP 3448
Sawn timber (Pinus Sylvestris) of dimension 50x150 mm was impregnated with CCA by a full-cell process. The timber was then dried in a conventional kiln or a special vacuum kiln where the timber was dried by circulating superheated steam. Drying time was 16 days and 2 days respectively. The aim of the investigation was to compare the physical appearence of the wood after drying by the two methods with particular reference to formation of checks. Moisture contents and checks were therefore recorded before and after drying. It was found that the number of checks formed was approximately the same by either drying system and no inner checks were found. The drying in superheated steam, however, caused bleeding of resin on the surface of the wood, which could be a disadvantage for some end uses.
M-L Edlund

Effects of artificial UV weathering and soft rot decay on heat treated wood
2005 - IRG/WP 05-40302
Oil and inert gas oven heat treated pine wood strips 100 µm thick were mildly heat treated (200°C, 30 mins linseed oil, 120 mins oven). Following treatment, specimens were exposed to UV weathering (300 hours) and decay by the soft rot fungus, Chaetomium globosum. The effects of each treatment were assessed by zero span tensile testing, microscopy and by FTIR. Tensile testing of heat treated strips showed greater strength losses in the oil treated samples (73%) than in the oven treated samples (26% loss). Heat treatment darkened the wood strips but this was photo-bleached on exposure to UV artificial weathering. The UV exposure caused some loss in tensile strength (35%) but the additional effects of UV on the tensile strength were less in heat treated wood (oil 15%, oven 18%). The combined effects of UV and fungi on the tensile strengths were less severe for treated wood than in untreated wood, (oil 4%, oven 18%) thus some protection was afforded by the heat tretaments. Exposure of untreated wood strips to the soft rot fungus caused some loss in tensile strength (32%), but heat treated wood showed small but not statistically significant gains in tensile strength after fungal exposure (oil, gain 30%, oven, gain 3%). Microscopic examination confirmed that a soft rot was minimal in heat treated samples, i.e. it was mainly confined to wood cell wall penetration. The combined effects of UV and fungi caused further losses of tensile strength in both oven and oil heat treated samples, but this loss was less severe than that which occurred in untreated controls. However, due to the severity of the initial losses caused by the oil heat treatment, the highest losses overall were in those oil heat treated samples exposed to UV (82%) and UV and decay (78%). Microscopic examination revealed that decay was more advanced in UV exposed samples. The FTIR spectra of oven heat treated samples did not show any change, while the oil heat treated samples increased absorbance at 1737cm-1 and 1450cm-1 relating to the presence of oil. Following fungal decay, no changes were observed, this corresponds with the cavity attack by soft rot fungi, which leave adjacent portions of cell wall material untouched. The ultra violet exposure affected the spectra of all specimens, increasing the absorbance at 1737cm-1. This relates to photo-degradation of the hemicelluloses, forming new carbonyl groups. In the UV exposed untreated wood there were also increases in absorbance at 1510 and 1160cm-1 relating to alterations in lignin structure.
M D C Hale, S C Ghosh, M J Spear

A summary of work carried out to compare natural and artificial weathering for preconditioning test specimens in testing anti-stain chemicals for wood in service
1976 - IRG/WP 266
Since 1972 work has been in progress within CEN to establish a European standard for the testing of wood preservatives designed to prevent blue-staining of wood in service. The method is based on the Butin test and involves pre-weathering of the samples prior to biological testing. The weathering regime employed is 6 months outside exposure from March to October. This imposes severe limitations on the number of tests that can be carried out each year and has prompted considerable interest in an artificial weathering procedure which can be used instead of natural weathering. Recently four European laboratories (EMPA, BAM, IC, PRL) have been involved in assessing artificial systems (Xenotest, Marr, Gardener wheel, weathering tunnel) and this report has been prepared at the request of CEN in order to assess the accumulated data and make recommendations back to the CEN. This document presents only a brief account of the work and fuller details can be obtained directly from the laboratories concerned.
D J Dickinson, A F Bravery

Xenon simulation of natural weathering of external joinery preserving - Finishing systems
1992 - IRG/WP 92-2412
Semitransparent wood stains ('lazures') for external joinery have developed by means of product combination towards complete wood finishing systems that are easy to applicate, have a good weathering resistance and low maintenance cost. The search for enhanced formulations and the possibilities to standardize these products or treatment systems are always facing long periods of weathering tests. Extensive research was conducted to compare natural weathering with artificial ageing, using a scheme based on two cycle units commonly used for artificial weathering and intermediate low temperature exposures. Statistical analysis of test results showed good similarity between both natural weathering and Xenon ageing
J Van Acker, M Stevens, M Nys

Durability of plywood made from soft- and hardwoods assessed according to ENV 12038 after artificial and natural ageing
2000 - IRG/WP 00-20191
Plywood was prepared from Norway Spruce and pure heartwood of Douglas Fir, Scots Pine, European Oak, False Acacia and Macoré using a phenol-formaldehyde glue. The panels of 38 mm in thickness were pre-conditioned according to the following procedures: a) 12 weeks storage at 20°C/65% rh, b) 2 weeks artificial weathering (with rain and UV-radiation at changing temperatures), and c) a natural weathering according to ENV 12037 for 3 month, 6 month and for 9 month whereby the ENV 12038 specimens were cut from the lap-joints. In general for softwood panels the decay was lowest after a 12 weeks` storage and the artificial weathering increased the decay rate more than the natural weathering applied. For False Acacia the durability was gained as predicted by EN 350-2 but not for the other species. Especially for European Oak and Macoré the durability was much lower than expected. Further, it has to be mentioned that the specimens usually showed a more intensive attack close to the nutrient media than at the top of the specimens. This indicates that the laboratory results might be influenced by the thickness of the panel tested because thinner material would be more equally degraded and thus would show a lower grade of durability.
H Leithoff, R-D Peek

Resolution from IRG Working Group II Sub-group 4 'Stain in timber in service'
1984 - IRG/WP 2230
Sub-group 4 of IRG Working Group II has completed a series of studies of artificial weathering as an alternative to natural weathering in relation to testing the efficacy of chemicals in preventing blue stain in service. The Sub-group reports that within the limits of the equipments studied and described in its report Document No: IRG/WP/2215 the extent of blue stain varied little as a direct consequence of varying the artificial weathering system. The Sub-group considers that any or all of the methods based on the Atlas, Marr or Xenotest systems (as described in Table 4 of Document No: IRG/WP/2215) are suitable on technical grounds for inclusion in a specified methodology.
D J Dickinson

Effectiveness of copper/chromium salts as wood preservatives against Limnoria tripunctata Menzies in laboratory tests
1977 - IRG/WP 431
During the last joint meeting of IRG and COIPM a co-operative programme of tests with copper/chromium salts as wood preservatives against marine borers was discussed and agreed. In this connection the results of a laboratory test in the BAM with Limnoria tripunctata Menzies will be of interest. But as the respective paper is written in German (H. Kühne; G. Becker: Laboratoriumsversuche über die Wirkung kupferhaltiger Schutzsalzgemische auf die Holzbohrassel Limnoria tripunctata Menzies) (Material u. Organismen 5 (1970) No 4, 307-319) a comprehensive summary is given in English for IRG-COIPM members.
H Kühne

Laboratory tests on light organic solvent preservatives for use in Australia. - Part 6: Soft rot resistance of three fully formulated preservatives on different timber substrates
2000 - IRG/WP 00-30245
The above-ground soft rot resistance of substrates treated with three fully formulated light organic solvent preservatives (Cuprivac Green WR, Impresol WR 205 and Vacsol) was studied using a modified vermiculite burial method. The substrates were sapwood of Pinus elliottii and P. radiata and heartwood of Eucalyptus regnans, Pseudotsuga menziesii, Shorea sp. (a lower and a higher density source) and Thuja plicata. Following artificial weathering, replicate test blocks were exposed to either Chaetomium globosum or Lecythophora mutabilis. C. globosum caused 3% or more mass loss of the water and solvent (white spirit) impregnated controls of all three hardwoods and two of the four softwoods, whereas L. mutabilis caused similar attack in only E. regnans and P. radiata. The P. menziesii and T. plicata heartwoods were naturally durable to both soft rot fungi and, hence, no further conclusions can be drawn. None of the preservatives, at the highest retention tested, protected E. regnans from attack by C. globosum, whereas the highest retentions of both the Cuprivac Green WR and Impresol WR 205 protected all other timbers from this fungus. At the highest retention, the latter preservative was the only one to protect E. regnans from L. mutabilis.
G C Johnson, M A Tighe, J D Thornton

Laboratory tests on artificial weathering of Quercus rubra crossties
1986 - IRG/WP 2252
Clear red oak (Quercus rubra) blocks were used to evaluate various types of accelerated aging tests including boil, steaming, and cyclic weathering. It was found that the repeated vacuum and pressure treatment of wood in water, steaming, oven-dry, and freezing appeared to be most effective in reducing the MOE in compression and hardness modules of wood specimens. Red oak crossties which were pressure treated with creosote - coal tar preservative were tested using the cyclic aging technique. This method will be used to establish correlation between short-term accelerated aging test results and long-term in service performance of wood crossties.
P Chow, A J Reinschmidt, E J Barenberg, S L Lewis

A technique for fructification and basidiospore production by Serpula lacrymans (Schum. ex fr.) SF Gray in artificial culture
1986 - IRG/WP 2255
A method for fructification and basidiospore production by Serpula lacrymans is outlined. A wheat flour/malt extract medium or an oat grain medium, enriched with alanine, tri-potassium phosphate and thiamine supported good fructification of the fungus at a temperature of 12°C. The influence on fructification of temperature, light and inoculum is discussed. To date, 22 stains from a total of 38 tested, fructify in culture.
S Cymorek, B M Hegarty

Fixation of copper-chrome-arsenic treated timber: A comparison of leaching methodologies
1996 - IRG/WP 96-50075
Five packs of kiln dried radiata pine heartwood were treated with copper-chrome-arsenic preservative treated, utilising a modified Bethell treatment schedule. Two methods of determining the level of preservative fixation were compared. These included the diphenylcarbazide method and simulated rainfall testing. The fixation levels were generally higher for tests involving simulated rain leaching. Fixation of copper-chrome-arsenic determined by the diphenylcarbazide method was found to fluctuate with time. Localised surface concentrations of preservative, 'hot spots', were suggested as the cause. Simulated rainfall appeared to provide a more realistic assessment method for determining potential preservative leaching of multisalt preservatives.
S Walley, P R S Cobham, P Vinden

A rapid method for collecting large numbers of subterranean termites from wood
1982 - IRG/WP 1165
A corrugated fiberboard trap is described which attracts large numbers of subterranean termites from infested logs. Single-trap collections in excess of 63 grams (wet wt.) for Reticulitermes virginicus (Banks) and 43 grams for Coptotermes formosanus Shiraki were taken one to three days following discovery by termites. If traps are removed from the source logs shortly after beeing attacked, termites are collected free from extraneous soil and cellulosic contamination.
J P La Fage, N-Y Su, M Jones, T Lawrence

Blue stain in timber in service. Results of further IRG collaborative tests to compare different artificial weathering systems
1981 - IRG/WP 2146
The previous work described in Document No IRG/WP/286 examined 3 preservatives (1% phenyl mercury succinate - PMS, 5% pentachlorophenol - PCP and 1.5% Preventol A4 - PA4) subjected to 5 different artificial weathering systems (BAM Xenotest, Cuprinol Marr, EMPA Xenotest, Gori Atlas and PRL Marr) and after natural weathering at 5 sites (BAM, Cuprinol, EMPA, Gori and PRL). Results showed good correlation between natural weathering and 500 hours in the Marr and Atlas equipments. Natural weathering gave somewhat variable results for PCP and PMS; BAM and EMPA were the most severe and the Cuprinol site least severe. Members of the ad-hoc Group decided during discussions at the IRG meetines in Peebles in 1978, that further work was desirable so that an extended range of fungicides and of weathering equipment could be examined. The 11 participants who agreed to co-operate in various phases of the new work were: BAM (Berlin), Cuprinol (UK), EMPA (Switzerland), Gori (Denmark), Hicksons (UK), Imperial College (UK), Penarth (UK), PRL (UK), Protim (UK), Sadolins (Denmark) and Technological Institute (Denmark).
A F Bravery, D J Dickinson

Water-based silicones on wood
1997 - IRG/WP 97-30144
Five waterbased silicones commonly used on masonry where tested as water repellents for wood. The Water Repellent Effectiveness was determined by swellometer-tests and by measuring the water uptake of samples after 24 hours complete immersion and by immersion in a water level of 4 mm for 24 hours. The different methods are compared and discussed. Artificial and natural weathering was performed to determine the durability of the water repellency. Non of the tested silicones showed a significant ASE. The gluability of three tested silicones with PVAc gave poor results. One of the silicone microemulsions and one silicone emulsion performed a water repellency that might allow their use on wood. Two commercial non silicone water repellents that where tested as controls had a lack of durability after weathering.
D Lukowsky, R D Peek, A O Rapp

Assessing the importance of degradation mechanisms on the loss of effectiveness of wood preservatives
2000 - IRG/WP 00-20193
Accelerated ageing systems developed for application to samples in the laboratory prior to biological tests, should reflect those natural deterioration processes that are likely to occur in the hazard classes defined in EN 335-1. Losses through evaporation or the effects of leaching have been recognised, however their importance, relative to other mechanisms has not been quantified. Degradation mechanisms including photolysis, thermolysis and hydrolysis have largely been ignored. This paper presents information from a study, conducted as part of a project supported by the European Commission (SMT4-CT96-2135), on the relative importance of these different mechanisms through a series of experiments using model compounds. These model compounds were selected because they have known susceptibility to one of the identified degradative mechanisms. TnBTO has been used to monitor photolysis, trihexylene glycol biborate to examine the effects of hydrolysis and lindane to monitor evaporation. The experimental data are compared to semi-natural exposure data. Support for ensuring that the various degradative mechanisms occur in the accelerated ageing systems is recommended.
E D Suttie, R J Orsler, T Dearling

Artificial weathering as an aid to assessing the effectiveness of chemicals for preventing blue stain in service - a co-operative study
1984 - IRG/WP 2215
The paper reports co-operative studies carried out within Working Group II of the International Research Group on Wood Preservation to assess the effects of different artificial weathering systems on the performance of fungicides to control blue-stain in service. It has been shown that Atlas, Xenotest and Marr equipments operated according to particular standard schedules can give essentially the same results for 5 of 6 fungicides tested.
A F Bravery, D J Dickinson

Artificial weathering exposure as an alternative for standard ageing according to EN 84 (leaching) and EN 73 (evaporation)
2002 - IRG/WP 02-20254
In order to verify potential weaknesses of wood preservatives fungal tests are carried out after ageing of wood preservative treated test blocks. The European standard EN 599 as a framework for efficacy assessment of wood preservatives includes the use of two ageing methods prior to fungal testing, namely a leaching method (EN 84) and an evaporation method (EN 73). The European research project "F.A.C.T." aimed amongst other objectives to provide in more realistic alternatives for both ageing methods. Artificial weathering systems generally used to assess the weathering resistance of exterior coatings was looked at as an alternative. For this purpose artificial weathering devices were selected which besides a control of temperature and light also allow for the impact of moisture by means of water spraying. UV cabinets with spray option were used to evaluate the effect of ageing of three wood preservatives: a waterborne Cu-HDO preservative, an oilborne triazole combination and a TBTO reference preservative. Based on EN 113 Basidiomycete testing of aged specimens a range of equivalent UVS systems proved to be suitable as an alternative ageing system prior to EN 84 and EN 73.
J Van Acker, M Grinda, D J Dickinson

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