IRG Documents Database and Compendium

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

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

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

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

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

Questionnaire: Facility for accelerated stake tests in unsterile soil
1981 - IRG/WP 2166
An acceptable name for this type of test facility has not yet been devised, but it has previously been referred to as a FUNGUS CELLAR or as a TROPICAL DECAY HOUSE. The attached pamphlet (What's New in Forest Research No.65) describes in broad terms the facility used for this purpose at FRI in New Zealand. Over the last two or three years several laboratories and commercial firms have installed so-called fungus cellars. At the 1981 I.R.G. Meeting in Sarajevo it was proposed that a survey be undertaken to obtain basic information on the various developments in this new area of biological testing. To this end, I shall be pleased if you complete the enclosed questionnaire and return it to: Dr J.A. Butcher, Forest Research Institute, Private Bag, Rotorua, NEW ZEALAND. A full report on this survey will be presented at the next I.R.G. meeting scheduled for Turkey in May 1982.
J A Butcher

Report on questionnaire: Facility for accelerated stake tests in unsterile soil
1983 - IRG/WP 2169
In October 1981 a questionnaire (IRG Doc. No. IRG/WP/2166) on the so-called fungus cellar tests in unsterile soil was prepared and despatched to 56 individuals representing various institutes, organisations, or companies. In addition a further 68 letters describing the purpose of the questionnaire were sent to additional IRG members who could request the full questionnaire if appropriate. This represented a contact with 125 individuals in 48 countries. A verbal report on the results of this survey was presented at IRG 13 in Cesme, Turkey. The present document formalises that report.
J A Butcher

Preservative requirements for exterior particleboard as predicted from accelerated laboratory evaluations
1976 - IRG/WP 265
Arguments for and against preservative treatment of exterior particleboard were considered; it was concluded that preservative treatment is desirable. Laboratory decay tests were conducted to determine levels of sodium pentachlorophenoxide required to protect exterior particleboard from decay fungi. The decay resistance of treated board was compared with that of timber (both naturally durable and preservative-treated) currently used in situations for which exterior particleboard is designed. A retention of 0.35% sodium pentachlorophenoxide per oven-dry board weight was considered to offer adequate protection to the board.
M E Hedley

Natural durability of wood in ground contact - A correlation between field and laboratory tests
1985 - IRG/WP 2182
A field test is being carried out to evaluate the natural durability of 20 hardwoods. The resistance to decay and termite attack was evaluated in accelerated laboratory tests. The results of the field test after 6 years and 8 months indicate that there is not necessarily agreement between results from laboratory and field tests. It is pointed out that apart from the artificiality of the laboratory tests, a possible cause of the discrepancies can be the different performance of the same wood species in different test sites.
M S Cavalcante, G A C Lopez, R G Montagna, M E S Fosco Mucci

Relative performances of DNBP and CCA wood preservatives in accelerated decay tests
1988 - IRG/WP 3496
The effectiveness of 2-sec-butyl-4,6-dinitrophenol (DNBP) was compared with that of CCA. Test blocks of Pinus patula and Eucalyptus grandis were impregnated to precisely known retentions of approximately 3, 6, and 10 kg/m³ CCA and solvent-borne DNBP respectively. They were then challenged in decay tests comprising soil burial and exposure to monocultures of Chaetomium globosum, Coriolus versicolor and Coniophora puteana. Decay was monitored by determining weight losses produced in the blocks over 15 weeks. Overall, DNBP performed more successfully than CCA. Specifically, a toxic threshold of 7.4 kg/m³ DNBP was shown in soil-buried Eucalypt, whereas this wood failed in soil even when treated to 10.43 kg/m³ CCA. A mycocidal effect of DNBP on Coniophora puteana was detected. Comparing costs, effective wood preservation using DNBP was cheaper than using CCA, and such costs would be significantly lowered with the advent of less toxic water-borne DNBP.
W H Schnippenkoetter, L D Abraham, A A W Baecker

Ground contact performance of wood treated by the MSU process
1990 - IRG/WP 3609
Environmental concerns have prompted a renewed interest in accelerated fixation schemes for CCA-treated wood. Results from stake tests of southern pine (Pinus sp.) treated using a conventional Bethell cycle are compared with matched stakes treated using the MSU Process. The effects of adding boric acid to the preservative formulation are also discussed. Differences among test plots are discussed.
H M Barnes, T L Amburgey, R W Landers

Comparison between agar-block and soil-block methods for wood-destroying Basidiomycetes
1992 - IRG/WP 92-2401
The object of this work is to compare these methods in order to provide some information to help in the choice between them. The comparison was made by a statistical analysis (factorial completely randomized design) and by a discussion about other aspects of each method. An evaluation of some fungi on attacking wood and a comparison between Picnoporus sanguineus isolated from carpophore and decayed wood were made. The results indicated that the loss of mass was greater in soil-block. Besides, the activity of the fungi in this method was more homogeneous than in agar-block. However the soil-block method presents some difficulties not found in the agar-block method. As related to the performance of Picnoporus sanguineus strains, the greater loss of mass occured when it was isolated from carpophore, no matter what method was used. These results give important indications about the biological characteristics and the source of the strains.
M B B Monteiro, S Brazolin, G Catanozi

Accelerated decay tests to investigate postulated effects of tannins on CCA efficacy in wood
1988 - IRG/WP 3497
Five groups of blocks (10 x 10 x 5 mm³) viz., Pinus patula, Pinus patula impregnated to 4% (w/w) tannin; Eucalyptus grandis, Eucalyptus grandis with natural tannins extracted; and extracted Eucalyptus grandis with tannins returned as above; were prepared. Blocks from each group were then treated to 0, 5, 10 and 15 kg/m³ CCA and challenged in four 15-week decay tests, viz., soil burial, and exposure to monocultures of Chaetomium globosum, Coriolus versicolor and Coniophora puteana. The effect of tannin on CCA efficacy was evaluated by weight losses produced. The antimicrobial effect of tannin in wood not treated with CCA was demonstrated. However, the presence of tannin did not effect CCA efficacy in wood at the preservative retentions tested, since weight losses in CCA treated Pine and Eucalypt, both with and without tannins, were similar throughout all tests.
U L Scherer, A A W Baecker

Délavabilité de bois ronds traités avec un sel CCA dans des conditions réelles de stockage. Incidence pratique de la fixation accélérée par étuvage. Impact effectif sur l'environnement
1993 - IRG/WP 93-50001-23
Un essai de terrain a été organisé pour mesurer concrètement, dans des conditions aussi proches que possibles des conditions réelles de terrain, les pertes effectives en produit de traitement lorsque le bois traité est soumis à des intempéries. L'essai a été conduit sur des bois ronds (poteaux), traités en autoclave par procédé Bethell avec un sel CCA de type C, avec comme finalité l'évaluation de la nature et des quantités de composés délavés en pratique, pour évaluer ainsi leur impact réel sur l'environnement au niveau du site de traitement. Compte-tenu des propriétés fixantes de ce type de produit, il était interessant d'identifier ces pertes à différents stades de la fixation, ainsi qu'après fixation compléte. Utilisant également les divers travaux et constats disponibles à ce jour sur les possibilités d'accélérer la fixation par l'étuvage, nous avons voulu observer et quantifier cette amélioration dans les mêmes conditions de terrain. Cet essai a été organisé et exécuté conjointement par le CTBA et la société FRANE BOIS IMPREGNES. Il conduit à 3 constatations principales: - Les pertes pratiques sont quantitativement nettement moins importantes que celles obtenues à partir des méthodes et échantillons de bois utilisés en laboratoire. - A l'issue et surtout au cours de la fixation les divers métaux se comportent de façon très différente, et on peut penser que la nature de la formulation a une importance notable sur ce comportement, même si dans tous les cas les quantités concrètement délavées restent faibles. - L'éuvage en sortie de traitement et dans des conditions adaptées permet d'obtenir spontanément, un résultat analogue à celui obtenu par un cycle de fixation traditionnel.
M Rayzal, F Larroze

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

Accelerated laboratory testing of preservatives on 13 North American wood species
1999 - IRG/WP 99-30201
The ability of selected water and solvent based biocides to protect wood against fungal attack was evaluated on 13 North American wood species using 7 decay fungi in a modified soil block test. Most preservatives were capable of providing protection at their recommended above ground and soil contact use levels. Many decay fungi caused substantial weight losses on blocks treated with chlorothalonil, copper citrate or copper dimethyldithiocarbamate. Most other preservatives performed well against a majority of fungi, but were susceptible to one or two of the test isolates. Aspen was the most difficult of the 13 species to protect against fungal attack. The results illustrate the need to confirm performance of new wood preservatives on the range of wood species to which they will be applied prior to field use.
J J Morrell, C M Freitag

Accelerated decay tests on DNBP-treated Pinus patula and Eucalyptus grandis
1987 - IRG/WP 3441
Blocks (10 x 10 x 5 mm³) of Pinus patula and Eucalyptus grandis were impregnated to 0, 1.5, 3.0 and 4.5 kg/m³ 2-sec-butyl, 4, 6 dinitrophenol (DNBP). They were monitored microscopically and for weight losses over 16 weeks against monocultures of Coriolus versicolor and Coniophora puteana. Treated ministakes (10 x 10 x 100 mm³) and blocks in soil contact were similarly monitored to determine weight losses and microbial succession. Weight losses increased progressively. Final losses after soil burial were 10% in Eucalypt and 4% in Pine treated to 4.5 kg/m³ DNBP. Comparable figures after Coriolus exposure were 30% in Eucalypt and 7% in Pine. Both timbers were protected against Coniophora by 3.0 kg/m³ DNPB when weight losses never exceeded 3%. Pine was less colonised than Eucalypt and least isolates were obtained from samples containing most DNBP. Succession was always initiated by bacteria and molds after 2 weeks. Basidiomycetes colonised Eucalypt after 6 weeks but were not observed in Pine. Bacteria attached to wood by glycocalyces were observed to produce lysis troughs in S3 layers of cell walls of DNBP-treated samples of both woods.
L D Abraham, A A W Baecker

A comparison between different accelerated test methods for the determination of the natural durability of wood
1996 - IRG/WP 96-20099
According to the European standard EN 350-1 the natural durability of wood is defined as: "the inherent resistance of wood to attack by wood destroying organisms". This standard also describes how, for certain hazard classes, the durability is determined. The two methods described in this standard are the kolleflask method (EN 113) and the field-stake-test method (EN 252). The EN 113 test gives results within a short period of time by using isolated fungi cultures. A good prediction from the test results to the natural durability of timber in use is a problem. In contrary, the test results of EN 252 in outdoor field tests show the durability of timber species under certain soil and climate conditions, but the test takes a long period of time (years to decades) before an evaluation can be done. In different countries in Western-Europe a discussion is going on about the use of tropical hardwoods and timber from fast growing plantages. The impact of this is that there is a growing need for alternative timbers, which can substitute well known durable species. Quite often the durability of the alternative species is not well known. To give a reasonable prediction of the durability of wood species within a short period of time, a reproducible, reliable and fast test method for predicting durability is needed. Previous research on this subject (Polman et al. 1992) showed that with the aid of an accelerated stake-test, useful results can be achieved. The research described here was done to develop such a method. For this reason, results from an accelerated soil bed test were compared with EN 113 fungal tests and a modified field-test EN 252. For a further comparison, softrot tests following the standard ENV 807 were performed.
H Militz, S G L Michon, J E Polman, M Stevens

Termite resistance of Malaysian and exotic woods with plantation potential: Field evaluation
1998 - IRG/WP 98-10289
An in-ground resistance of selected Malaysian and exotic timbers to attack by a representative aggressive subterranean Coptotermes termite was evaluated as part of an on-going collaborative research between the Forest Research Institute of Malaysia and the University of Hawaii on termite control of building timbers under humid tropical conditions. A test site at FRIM, highly susceptible to the subterranean termite Coptotermes curvignathus was chosen for study. The accelarated test protocol consisted of burying small (2 x 2 x 2 cm3) wood blocks of the following timber species at 15-20 cm below-ground with the immediate environment manipulated by addition of residues from oil palm fibres and venners of decay susceptible woods and concealed with forest top soil: Casuarina equisetifolia, Azadirachta excelsa, Tectona grandis (both Malaysian-grown and Burmese material), Hevea brasiliensis, Acacia mangium, Albizia falcataria, Araucaria cunninghamii, P. sylvestris, Koompassia malaccensis and K. excelsa. After 28 days, it was found that the results of the subterranean termite resistance test are consistent with the known/expected termite resistance of these woods when compared with previous natural durability stake test records of FRIM.
A H H Wong, J K Grace, L H Kirton

Window test. Direct testing of wood resistance to decay: A study of its fitness, its reliability and its accelerating factor
1984 - IRG/WP 2219
This is the results of an experiment using the window-test specimens, exposing the specimens to three different types of testing procedure: 1. Natural infestation in the open air; 2. Artificial infestation and exposure in the open air; 3. Artificial infestation in a green-house. The results show good similiraties of the three parallel tests in term of decay, and assess the reliability of the window-test, its fitness and particularly its accelerating factor.
G R Y Déon, L N Trong

Accelerated termicidal performance data for new water-based copper linoleate formulations
1996 - IRG/WP 96-30104
An organic solvent based copper linoleate (Culin) has proved itself as an effective wood preservative in long term field trials in South Africa over a period of 30 years. Whilst the organic solvent based product offers good wood preservative performance, primary industrial interest has been in an emulsified version of the product. The objective of this study was to evaluate the influence of two different emulsifiers on the performance of emulsified versions of Culin against subterranean termites under accelerated field test conditions. The results indicated that the emulsions offered levels of protection that did not differ significantly from that of the original Culin formulation and CCA at equivalent copper retentions. However, variations in the performance of the products in the test indicated that the choice of emulsifier could influence the predictability of the products in the field.
D Conradie, P Turner

In-house accelerated method for testing decay resistance of treated wood
2004 - IRG/WP 04-20286
Fungicidal compounds often change their effectiveness when they are incorporated into candidate formulations. For this reason fungistatic effectiveness needs to be re-evaluated as many times as the formula has been modified for better performance. To avoid multiple expenses, in-house fungistatic tests are essential. Our goal was to develop in-house usable, simple but reliable and reproductive procedure for testing decay resistance of the Sansin priming formulae without a need for special testing equipment. Our preliminary trials have proved that commercially available, heat processed wood pellet fuel can be used as an excellent substrate for growing certain wood rotting fungi. In contact with water wood pellets quickly disintegrate and convert into sawdust, gaining up to three times increase in volume. When wood pellets are wetted with water containing hydrogen peroxide, the vapors of this antiseptic kill non-desirable air-borne contaminants and protect the substrate from further contamination for as long period as peroxide remains in the substrate at sufficient concentration. When peroxide protected substrate is spawned with well-organized fungal organisms (for example true decay/test fungi), they will rapidly colonize the substrate and develop a powerful mycelial network capable of decomposing most of the natural fiber based materials. Treated and non-treated wood specimens were buried in spawned, hydrogen peroxide protected wood pellet fuel-based substrate and placed in transparent, perforated plastic containers to determine the effect of this procedure on rapid colonization and accelerated wood degradation. Parallel test was set up with specimens inserted in 150mm diameter dishes containing fungal cultures developed on the beer based agar medium. The results after 45 and 90 days of exposure to the brown rot causing fungus Gloeophyllum trabeum indicate that the weight loss in control blocks in containers was higher than in the dishes for 7 and 11 percent respectively.
N Vidovic

Comments on leaching in view of accelerated testing
1977 - IRG/WP 294
We developed an accelerated test for leaching at elevated temperatures (75-85°C). This test was used for the examination of 11 preservative formulations containing Cu, Zn and As. The data obtained from these experiments were compared with data on some formulations tested by ASTM standard leaching test. The method consists in making a large surface to volume ratio of wood from a treated block by cutting into sections approx 40 µm thick and in cyclic extracting preservative salt with a total of 250 ml of distilled water at the elevated temeratures for 24 hours. In conclusion, the new accelerated teet proved to be a fast method which provided reproducible dala on the leech-resistance of various inorganic preservatives. The data are comparable with data of traditional leaching tests at room temperature.
J Rak

Possible durability transfer from durable to non durable wood species. The study case of teak wood
2001 - IRG/WP 01-10392
Teakwood is well known for its excellent natural durability, mostly due to its high proportion of extracts. Amongst these extracts, quinones, and more precisely some naphtoquinones (such as lapachol) and anthraquinones (such as tectoquinone) appear to play a crucial role in the resistance to wood decay organisms. At a laboratory scale, sawdust from malaysian teak heartwood has been extracted under different temperatures. These extracts, as well as solutions of commercialised lapachol and tectoquinone were used to treat pine sapwood mini blocks. Such treated and leached samples were used for accelerated fungal tests using basidiomycetes. The results have shown that protection against fungi was achieved through these treatments. Nevertheless, laboratory extracts from teakwood and commercial quinones performed differently, arousing then questions on this way of preserving non durable wood species.
M-F Thévenon, C Roussel, J-P Haluk

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