IRG Documents Database and Compendium


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Development of a Weatherometer to Accelerate the Surface Checking of Wood
2008 - IRG/WP 08-20388
There is significant interest in developing preservatives that are better at preventing wood from checking. Currently, however, there is no accepted test methodology for accelerating the development of checks in wood samples so information on the effectiveness of treatments at restricting checking can be obtained more quickly. This paper describes the development of a new type of weatherometer (Accelerated Check Tester) and associated weathering cycles to accelerate the surface checking of wood. The device permits the testing of realistic-sized decking board samples that are oriented horizontally and restrained by fixings. It uses computer-controlled water spray and infra-red heating systems to expose samples over a 5 day period to wetting and drying cycles. Desiccated air is also blown across the surface of samples to further increase the effectiveness of the drying cycle. The Accelerated Check Tester operated continuously and trouble-free for 24 weeks during an experiment, which examined the effect of different weathering cycles on the checking of southern pine and western red cedar decking samples. Samples exposed in the Accelerated Check Tester developed large numbers of checks, some of which were quite big, particularly those in southern pine samples. Weathering cycles that increased the severity of drying by increasing drying time or temperature did not significantly increase checking. Similarly, the inclusion of a freezing step in the weathering cycle had little effect on checking. In contrast, samples subjected to a cycle that included exposure to ultraviolet light developed significantly more and larger checks than samples subjected to any of the other cycles. Checking was much more pronounced in southern pine samples than in western red cedar samples. The Accelerated Check Tester should be a very useful tool for obtaining information on factors that affect the checking of wood. Furthermore, it could also allow companies developing wood preservatives and associated water repellent additives to rapidly obtain information on the ability of treatments to restrict checking and so shorten the development time for new wood protection systems.
R Ratu, P D Evans


Proposal for further work on accelerated ageing
1988 - IRG/WP 2314
M-L Edlund


How to Document the Performance of Super-Critical Treated Wood in above Ground Situations?
2005 - IRG/WP 05-20316
The paper presents practical experiences from the preparation of a new preservative treated wood product for introduction to the market. The product in question is Superwood™, which is treated with organic biocides using CO2 in a supercritical state as a solvent. The question is how to evaluate the performance of a new product such as Superwood™ in order to get an acceptance on the market and fulfil the formal requirements. In the European Union countries, the EN 599-1 is the standard that needs to be complied when approving a new product for the market, but it only focuses on the toxic limit against representative decay fungi according to EN 113. However, decay test, above ground and other forms of field tests are optional, this is not in line with the traditional test philosophy in the Scandinavian countries. The open question is to which extent treatment to the level of the toxic threshold value also ensures a long service life and expected performance of the treated commodity. Superwood™ is evaluated using a strategy, in which basic laboratory tests are done to get the toxic value (according to EN 599-1) and in addition a number of field tests are done including accelerated testing in the tropics. These tests are focussed on the evaluation of the performance criteria such as durability and service life and maintenance requirements. These questions must be answered by the producer without having a full record of performance test for their new products. A short status on the test performed on super-critical treated wood (Superwood™) is presented. Based on a comparison between field test in Scandinavia and in the tropical Malaysia a service life of more than 25 years for a specific supercritical treated product is estimated. It is stated that the existing European standardisation system is insufficient when it comes to service life prediction. A number of important questions need to be addressed by the European standardisation system as soon as possible because the market and the public opinion change quickly due to environmental concern.
N Morsing, A H H Wong, F Imsgard, O Henriksen


A rapid field bioassay technique with subterranean termites
1983 - IRG/WP 1188
Details are summarised of a field procedure which is designed to ensure continuous exposure to a replenishing termite biomass. After pre-baiting to determine the presence and identification of a termite hazard, test specimens (35 x 35 x 250 mm³) are installed vertically in the ground adjacent to and in contact with bait specimens of the same dimensions and interconnected by susceptible feeder strip.
C D Howick, J W Creffield


Studies on accelerated ageing procedures with TBTO-treated wood
1985 - IRG/WP 2244
The efficacy of various procedures for accelerated ageing of organotin based wood preservatives in treated wood has been investigated. It was found that leaching of the treated wood samples in water according to the European Standard EN 84 was not satisfactory for organotin based preservatives and is probably also unsuitable even for other types of organic solvent preservatives. Keeping tributyltin oxide (TBTO) treated samples in a heating cabinet at 70°C for five weeks, however, had a considerable effect on the breakdown of TBTO and the subsequent decay test. Therefore, an ageing procedure involving a heating period should be considered for all organic solvent wood preservatives. The investigation also confirmed that elevated temperatures accelerate the degradation of TBTO and that there is a strong correlation between the percentage of TBTO in the wood and its resistance against decay.
J Jermer, M-L Edlund, B Henningsson, W Hintze


Japan's comments on ISO/DIS 12583-1/2
1996 - IRG/WP 96-20100
The paper describes an accelerated field test for the evaluation of timber preservative formulations against subterranean termites. The method has been adopted by the South African wood preservation industry as a screening method for the approval of wood preservatives for use under SA conditions. The method which is based upon the fungal cellar test offers a rapid means of evaluating the comparative performance of new wood preservative formulations in an environment that accurately reflects field conditions.
P Turner, D Conradie


E.R.C. Pole Tester
1982 - IRG/WP 2190
Operating instructions for the ECRC pole-strength tester 120kNm 'PEST'.
G Elcock


The accelerated field simulator (= fungal cellar)
1982 - IRG/WP 2170
G C Johnson, J D Thornton, H Greaves


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


Accelerated fixation of CCA in borak bamboo (Bambusa balcooa Roxb.) of Bangladesh
2001 - IRG/WP 01-40193
CCA-C fixation study on impregnated (6% CCA solution), then boiled, oven-dried, normal, air-dried and steamed bamboo slices of air-dried borak bamboo (Bambusa balocca Roxb) of Bangladesh, revealed almost complete fixation in steamed (accelerated fixation) and air-dried (3 weeks, slow fixation) bamboo slices compared to moderate to slow fixation in boiled, oven-dried, normal and 24h air-dried slices.
A K Lahiry


Short-term field test method with accelerated infection of Basidiomycetes in wood
1981 - IRG/WP 2155
In the ŠIPAD - IRC Wood Protection Laboratory an attempt has been made to develop a simple short-term method for field testing out-of-ground contact wood using accelerated infections with Basidiomycetes. This method makes it possible to obtain a preliminary assessment of a preservative's quality and to estimate the possibility of achieving promising results in more expensive long-term tests. The idea was to use water traps (reservoirs) and 50 x 25 x 15 mm³ laboratory infected pine blocks as the substrate to improve the possibility of inoculation of L-joints.
N Vidovic


Options for accelerated boron treatment: A practical review of alternatives
1985 - IRG/WP 3329
Boron wood preservatives are almost exclusively applied by momentary immersion and block diffusion storage. Alternative techniques are described which can be used to accelerate boron treatment. Diffusion coefficients have been derived to define the acceleration of diffusion with increasing temperature. Schedules are described for pressure impregnation of green timber, involving steam conditioning, evacuation and alternating pressure method treatment. Timber Preservation Authority penetration and retention requirements can be met in approximately 4-5 h. The optimum schedule, however, included a 12 hour holding period between steaming and preservative treatment. A method of applying boron preservatives as a vapour is described, Trimethyl borate vapour reacts with wood moisture to form boric acid. The kinetics of this reaction, however, are very fast. This limits treatment to timber dried to very low wood moisture contents.
P Vinden, T Fenton, K Nasheri


Accelerated ageing of preservatives in treated wood
1988 - IRG/WP 3476
New preservatives are tested in the laboratory and often in field tests before they are used commercially. Some preservatives, however, tested in the laboratory do not show the expected stability when used in service. The differences between laboratory tests and practical use can never be completely eliminated but must be minimized as far as possible by relevant testing methods. Studies of the effect of different accelerated ageing procedures on the chemical degradation and the wood preserving capacity of six different fungicides or combinations thereof have been carried out. Chemicals tested were tributyltinoxide (TBTO), tributyltin naphthenate (TBTN), furmecyclox, benzalkoniumchloride (AAC) + guazatin and pentachlorophenol. The ageing procedures included exposure of test specimens in a wind tunnel (according to EN 73), in an oven at 40°C, 60°C and 70°C, leaching (according to EN 84) and combinations of these procedures. The influence of the different accelerated ageing procedures on the chemical degradation and toxic effect of different fungicides was obvious and, for some procedures and chemicals, comparable with experiences from practice.
M-L Edlund, B Henningsson, B Jensen, C-E Sundman


Are fungal cellar tests really necessary?
1989 - IRG/WP 2333
During the past decade the range of methodology used to evaluate wood preservative potential has significantly expanded. At the forefront of these new tools available to the scientist·is the fungal cellar. This technique, as currently applied, involves the exposure of treated and untreated samples to conditions of moisture and temperature which ensure optimum fungal attack. By comparison data with that obtained on similar preservative systems in conventional stake tests, acceleration factors for predicting performance have been developed. This discussion paper examines the philosophy influencing the development of fungal cellar testing, and provides an alternative viewpoint.
J N R Ruddick


Leaching of Active Components from Preservative Treated Timber. Stage 1: Semi-Field Testing
2004 - IRG/WP 04-20302
The project is aiming at finding realistic leaching rates from preservative-treated wood in use class 3 (above ground). The project focuses on developing a field trial method for investigating leaching. Panels are subjected to outdoor exposure under natural weather conditions at a test field at the Danish Technological Institute. The leachate is collected and monitored by chemical analysis of the active ingredients. The project is ongoing and the paper presents results from approximately 12 months’ of exposure. The study includes commercially available organic and inorganic fungicides using 4 different application methods: vacuum-pressure-, double-vacuum-, flow coat and supercritical treatment. Different test set-ups examine the influence of a number of different parameters. The results obtained from outdoor exposure will be compared with a laboratory test method (proposal of CEN/OECD, DOC TC38 WG 27 N039). The method investigated has proved to be useful in characterising the leaching behaviour from preservative-treated wood. The results from the present project are intended to serve as part of the basic documentation according to Directive 98/8/EC (The Biocidal Products Directive, BPD) for leaching of active ingredients in use class 3.
N Morsing, B Lindegaard


An investigation to assess the feasibility of developing an accelerated laboratory test to determine the abrasion resistance of lesser-used timber species for use in marine constructio
2005 - IRG/WP 05-20317
The paper describes the evaluation of a laboratory-accelerated test to compare the shingle abrasion resistance of current and potential timbers for use in marine construction. Useful results were achieved in 47.5 hours, but identified a number of issues to be resolved for the test to be refined and the subsequent results to be interpreted correctly.
G S Sawyer, J R Williams


A comparison of the effectiveness of a vacuum oven and a wind tunnel in the accelerated ageing of treated wood by evaporation
1989 - IRG/WP 2334
R J Orsler, G E Holland


Multiple-Phase Pressure (MPP) Process: One-stage CCA treatment and accelerated fixation process. 5. Treatment of Sitka spruce and Scots pine
1999 - IRG/WP 99-40136
The suitability of the MPP Process for CCA treatment and accelerated fixation of species other than Radiata pine was assessed by pilot plant trials on UK-grown Sitka spruce (Picea sitchensis) and Scots pine (Pinus sylvestris). Pressure and vacuum kickbacks of spruce (14 l/m3) and Scots' pine (122 l/m3) were both substantially lower than that generated during treatment of radiata pine (369 1/m). Total Organic Carbon (TOC) in kickback from spruce treatment (~ 750 ppm) was approximately half that in Scots pine kickback (~ 1400 ppm), and were substantially less than TOC generated during treatment of radiata pine (~ 2000 ppm). Extent of CCA fixation (spruce: 93%, Scots pine: 97%) was similar to that obtained with radiata pine (97%). To reduce post-treatment drippage, caused particularly by the refractory nature of spruce, a modified Bethell process was found most appropriate for MPP treatment rather than modified Lowry schedules used with radiata pine. Use of hot CCA solutions did not improve penetration into spruce and some collapse (washboarding) of early wood was a feature of its treatment.
M E Hedley, K Nasheri, G Durbin


Accelerated wood decay in a soil bed test under greenhouse conditions compared with a stake test under field condition
1991 - IRG/WP 2384
The rate of decay of oak, beech, Douglas fir, pine and spruce stakes in an outside test field were compared with the decay rate of the same species in a greenhouse soil-bed test. Strength loss after four and six months respectively was measured by determining the compression strength parallel to the grain. The results show that all species, strength loss in the greenhouse was 2 to 4 times higher than under field conditions. The rate of strength loss correlates with the rate of weight loss.
J E Polman, S G Michon, H Militz


Estimation of service life of durable timber species by accelerated decay test and fungal cellar test
2002 - IRG/WP 02-20249
Many kinds of durable wood species for outdoor uses has been imported from all over the world to Japan. However information on the natural durability of these species is not sufficient to estimate the service life of them in the climate of Japan. Highly durable species such as Jarrh, Teak, Ipe, Ekki, Selangan batu, Red wood, Western red cedar showed no significant percent mass losses by accelerated decay test according to the JIS Z2101, but some of them are degraded during fungal cellar test for 4 years . The decay rating (0:sound to 5:totally decayed) of them after 4 years exposure was 1.0, 2.0, 0.0, 1.0, 0.0, 2.3, 5.0 respectively. This results indicated that the conventional accelerated decay test could not evaluate the natural durability of these highly durable species at all. Solid wood specimens treated with boiling water at 120? for one hour are subjected to the same JIS test, and the obtained percent mass losses of these species are 1.2, 2.9, 1.9, 3.8, 4.7, 17.5, 0.0 % by a brown rot fungus, Fomitopsis palustris, and 17.5, 14.3, 3.3, 8.2, 4.2, 0.0, 18.3 % by a white rot fungus, Trametes versicolor respectively. Pre-treatment of solid wood specimens for removal of heartwood extractives before a accelerated decay test would be an effective way to evaluate the natural durability of highly durable species in a laboratory.
K Yamamoto, I Momohara


The Pilodyn instrument as a non-destructive tester of the shock resistance of wood
1978 - IRG/WP 2107
A new non-destructive shock resistance tester, the PILODYN, has been developed. The instrument measures the fracture surface area created by a constant amount of energy. It operates by shooting a blunt pin into wood by an exact amount of energy. The penetration depth is read on a scale. A wide field of application is open to a non-destructive shock resistance tester such as: 1) assessment of the residual strength of poles decaying from the outside; 2) laboratory evaluation of biodeteriorated wood; 3) the state of wood foundations and woody pilework; 4) degree of chemical decomposition of wood; 5) degree of thermal decomposition of wood; 6) measurement of the density (strength) of standing trees; 7) measurement of the density (strength) of sawn timber; 8) production control of wood based panel boards. A review of existing test results as well as new results are presented containing items 1, 6 and 7. An evaluation of the potential of the PILODYN is attempted.
P Hoffmeyer


A new approach to the maintenance problems of wooden railway sleepers
1986 - IRG/WP 3392
The microenvironment of wooden railway sleepers is being investigated to assess their condition to determine the necessary treatment, repair and replacement criteria. The research work involves the development of an integrity tester to determine the condition of sleepers, a remedial treatment of sleepers by selective application of boric acid and a synthetic repair system.
W Beauford, P I Morris.


Rapid leaching test
1991 - IRG/WP 2367
An accelerated test which is suitable for measuring the extent of metal fixation in both chromium and non chromium containing preservatives is described.
J A Cornfield, M Bacon, A Lyman, C Waldie, M R Gayles


Natural durability studies in an accelerated field simulator - A novel approach
1983 - IRG/WP 2197
A study of the natural durability of untreated timbers to both decay and termite attack is described. The work illustrates the versatility of the Accelerated Field Simulator as a novel approach to biodeterioration research.
G C Johnson, J D Thornton, J W Creffield, C D Howick


Patterns of long-term performance - How well are they predicted from accelerated tests and should evaluations consider parameters other than averages?
1998 - IRG/WP 98-20130
This paper is a discussion of whether different service-life distribution patterns of products treated with unlike preservatives can be predicted, modeled, characterized, or even anticipated from accelerated laboratory tests. Graphic displays of data from Forest Products Laboratory field plots with preservative-treated and fire-retardant-treated stakes demonstrate the importance of local environment as a factor that affects field performance and exhibits differences in dose-response patterns among treatments. These distribution patterns are discussed with reference to early failures, first quartile and median failure times, and distribution about medians. Questions are then asked about the relevance of these parameters to practical applications, about the need to consider population characteristics other than average in evaluations on new preservatives, and about the capability of accelerated tests to estimate these parameters.
R C De Groot, J W Evans


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