Your search resulted in 527 documents. Displaying 25 entries per page.
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
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
The accelerated field simulator (= fungal cellar)
1982 - IRG/WP 2170
G C Johnson, J D Thornton, H Greaves
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.
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
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
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
Fungus cellar testing as an evaluation method for performance of treated timber in ground contact
2001 - IRG/WP 01-20227
A fungus cellar method for the accelerated evaluation of performance of treated wood in ground contact is described. The test soil comprised of sandy loam, vermiculite and Japanese horticulture soil "Kanumatsuchi" in a ratio of 6:2:2 by volume. The soil was inoculated with the dominant test fungus isolated with selective medium from decayed wood samples. Pairs of treated and untreated wood specimens Japanese cedar in contact with each other were buried vertically for two thirds their length. Assessment of the specimens was carried out periodically using the FFPRI graveyard damage index six- grade scale. Important factors for accelerating decay were the moisture control of the mixed soil, temperature and relative humidity, and the maintenance of fungus activity. The fungus used for inoculation favored a soil water holding capacity (WHC) of 50-80%. Under these conditions the untreated control specimens had a damage index in six months equivalent to three years FFPRI graveyard test service life, the decay accelerating rate by the fungus cellar to the graveyard test was 6 times. Under higher soil moisture conditions (WHC>80%) in the fungus cellar, soft rot was dominant and the decay rate was slower. DDAC treated specimens (8.4kg/m3) had a damage index of 2.6 in three years and 3.0 in four years. DDAC treated specimens (8.2kg/m3) in the graveyard test have been shown to be durable for 12 years (damage index of 2.3 in ten years and 2.6 after 12 years). This fungus cellar method has been shown to accelerate decay in DDAC treated specimens 3 times or more in comparison to the FFPRI graveyard test. On the other hand specimens treated with Copper-azole (6.0kg/m3 as retention of actives) had a damage index of 0 after eight years. The average service life in the FFPRI graveyard test is not decided as the Copper-azole treated specimens are in sound condition so it is not yet possible to evaluate the accelerating rate for the Copper-azole by the fungus cellar method. The fungus cellar method will be an useful method for the accelerated evaluation of performance of treated wood in ground contact provided the test conditions can be controlled.
Attempt for developing a new method for above ground field testing of wood durability
2000 - IRG/WP 00-20199
Field testing remains the most appropriate way for evaluation of wood preservatives or natural durability of wood species. Above ground tests are designed to answer specific questions concerning the outdoor utilisation of wood. Such methods supply additional information and confirm or reject preliminary laboratory results. The European standard (ENV 12037, "lap-joint") for assessment of the durability of preservative treated wood in above ground testing has recently been proposed. It may also be used to assess the natural durability of wood. The objective of the present paper is to bear some discussion on alternative above ground test methods. The existing lap-joint field test corresponds to the real exploitation conditions of timber, but shows no decay after 2-3 years of exposure. This could be misleading when assessing the efficiency of preservatives. The method suggested acts more quickly compared to the lap-joint method with regard to mould, stain and, presumably, decay fungi. It is an accelerated above ground field test providing conditions favourable for fungal growth, but following close the fluctuations of climate. Results are shown where samples treated with preservatives for above ground use and untreated samples were exposed to the accelerated above ground test for several months. Fungal discoloration of the timber surface was classified by visual examination according to a seven-grade scale. The field test described here may be recommended for quickly testing of the natural durability of wood in above ground conditions as well as for approval of preservatives.
N Terziev, M-L Edlund
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
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
Leaching of active components from preservative-treated timber. Stages 2 & 3: Laboratory testing and comparison with semi-field testing
2004 - IRG/WP 04-20303
This part of the project is focussed on leaching from preservative-treated wood obtained by the laboratory test method CEN/OECD draft guideline, February 2003 ”OECD guideline for the testing of chemicals proposal for new guideline XXX. Estimation of Emissions from Preservative-treated Wood to the Environment: Laboratory Method for wood held in the storage yard after treatment and for wooden commodities exposed in Use Class 3 (not covered, not in contact with the ground).” Preservative-treated test specimens are emerged in water. The specimens are immersed two days a week in a 60 days period. On each immersion day 3 immersions are carried out. One sample is immersed in water 18 x 3 times. Each immersion takes one minute. Between each immersion the specimens are stored in climate chambers. Water (emissate) is retained for chemical analysis for active ingredient to determine the leaching. The study includes commercially available organic fungicides using vacuum-pressure treatment as an application method. The preservative used is the preservative used in Nordtest project 1582-02 named M1. The investigation includes two different periods of fixation, one with a long fixation period and one with a short fixation period of the active ingredient before the immersion testing. The results obtained from laboratory testing are compared with the semi-field exposure. The method developed for in-service testing has proved to characterise the leaching behaviour from preservative-treated wood. However, there is no good correlation between field-testing and the CEN/OECD laboratory testing method for the product involved.
N Morsing, B Lindegaard
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
Experiments in accelerated ageing
1984 - IRG/WP 2223
Experiments using a vacuum oven to accelerate the evaporative loss of g-HCH from treated wood blocks have indicated that the method described in this paper has the potential to reproduce in a relatively short time the distributions and loadings of the insecticide that are found during natural ageing. By contrast, the wind tunnel removed the volatile material in a way not found in natural ageing and characterised principally by the rapid removal of material close to or on the wood surface. Theoretical considerations reinforced these practical observations indicating that the vacuum oven could provide a much quicker means of attaining the condition that is likely to exist in aged timber.
R J Orsler, M W S Stone
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.
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.
Standard and accelerated testing of boron-additive wood protection systems
2005 - IRG/WP 05-30381
The main objective of this research was to determine the effectiveness of boron-additive protection systems for above ground applications by means of field testing. The two field test procedures used are based on the L-joint test described in the European standard EN 330. For the first set up the boron treated timber was coated in accordance with the standard EN 330 system. The second set up is based on an accelerated test simulating uncoated applications and includes an additional moistening of the jointing area. After three years of aboveground exposure, boron preservatives are still providing an adequate protection to coated L-joint specimens. Based on the results obtained it can be concluded that boron-based compounds still provide good protection after three years of natural weathering when protected by a three-coat finish. Similar uncoated L-joints treated the same way show rapid deterioration under the accelerated exposure conditions applied. The mass loss data revealed a significant level of decay for the uncoated specimens even when treated with boron-additive formulations. This is attributed to the high leaching hazard related to the accelerated exposure method used. The latter proves to be too aggressive for all tested boron-based preservatives when unprotected by surface coatings. A treatment with 1 % CCA under the same conditions was still performing adequately after 3 years even under accelerated L-joint exposure of uncoated test samples.
A Mohareb, J Van Acker, M Stevens
Evaluation of the protective means of some wood preservatives by means of accelerated tests
1973 - IRG/WP 232
In site conditions of the eastern site in the forest-steppe part of the Krasnovarsk region, the relative effectiveness of a series of wood preservatives was obtained by means of field tests. To obtain a more accurate evaluation of the protective qualities of these accelerated tests were carried out in laboratory conditions. In 9 boxes filled with non-sterile soil taken from the site, 72 samples of pine wood (in sizes of 20x20x30 and 20x20x5 mm³) soaked in copper naphthenate, pentachlorophenol and the compound FHM-7751 in three different concentrations were placed. In 3 boxes decay was mainly due to fungi causing limited rotting. In the other 6 boxes the soil was infected with the basidiomycete fungi Hymenochaete sp. and Coniophora cerebella in order to obtain more reliable results of the protective properties of the wood preservatives. Uniform distribution of infection was insured by placing cubes of wood infected with a pure culture of the fungi under test between the faces of two adjacent samples. Tests were carried out in an air temperature of 20-24°C with a relative air humidity of 70-80%. Soil humidity relative to its absolute dry weight was maintained at 30%. The decay of wood was measured by weight loss. Duration of tests was from 1 to 3.5 years. The advantage of the method used lies in the uninterrupted action of micro-organisms in the course of a long period while in field tests samples are subjected to attack only during the short Siberian warm period of the year. Moreover in field tests the samples do not always find themselves in the fungus infected zone and the decay is caused by imperfect fungi having only a moderate effect. A drawback of this method is the isolation of the sample as a result of which the soil zone around the treated samples is deprived of the influx of new micro-organisms, while available micro-organisms find themselves in severe conditions which become worse with the increase in the concentration of the wood preservative. As in field tests the accelerated tests have shown pentachlorophenol (PCP) to give the best protection. Samples after 6 months in the soil and with an absorption of 3 kg/m³ begin to be attacked by staining fungi, non-spore carrying bacteria and spore yeasts. With an absorption of 8 kg/m³ the samples are practically immune to micro-organisms. Analysis carried out a year after placing the samples in the soil has shown the samples to be in a good condition whether they have been treated with the maximal or minimal dose of PCP. The condition of the samples in analogous when subjected to the action of not only fungi causing moderate decay but also the basidiomycete fungus Hymenochaete sp. Samples treated even with minimal doses of wood preservative showed no signs of decay while the weight of untreated samples fell by 74 and 92% according to size. In non-sterile soil, together with fungi causing soft rotting, there develops to a sufficient extent mycelium of the basidiomycete fungus Lentinus lepideus. Nevertheless, after 2.5 years of accelerated tests, and in spite of the fairly high development of Lentinus lepideus in the soil, the condition of treated samples corresponded to a preservation (durability) index 100. The treated samples were immune to mycelium of Lentinus lepideus even in spite of the fairly strong attack at the beginning of the test by ammonia-forming bacteria and wood-staining fungi. Tests with Coniophora cerebella were the longest (3-5 years). Visual inspection showed decay of controls only. Treated samples, irrespective of the amount of PCP used, showed no signs of decay or weight loss. The results of accelerated tests agree with field tests. But sometimes there are found on the surface of samples mycelium and white well-branched wafts (fans) of Hymenochaete sp. The appearance of hymeno-mycetes seems to indicate their adaptation to PCP and the beginning of decay. Much attention is now given to the study of the reduced effect of PCP due to the adaptation of micro-organisms. The weakening of the protective action of wood preservatives leads also to their depletion in the wood while in service. The study of the microflora of samples in laboratory and field conditions has shown that in both cases bacterial flora predominates in the process of decay of wood treated with PCP. It is represented by spore-carrying as well as spore-free forms. With the increase of wood preservative loadings the spore-free forms predominate. The species composition of fungal flora has little variety on wood samples treated with PCP. The species resistant to it are, in field tests, Trichoderma lignorum and Fusarium sp.
I A Petrenko
A new concept for the evaluation of wood durability for out of ground contact using accelerated L-joint testing
1997 - IRG/WP 97-20123
Since the wood preservation sector is developing in favour of defining exactly the utilization of wood products and preservation techniques as a function of the envisaged hazard class, more in particular the hazard classes 3 and 4 (EN 350) there is obviously a need for a test method evaluating natural durability for out of ground contact applications. Based on the L-joint test as described in the European standard EN 330 a test method is under evaluation to determine the out of ground contact durability of various temperate and tropical wood species. Major parameters in the accelerated L-joint durability test are: the open joint structure, an exposure with 10° inclination facing sout west, tenon members in a 50/50 beech - Scots pine sapwood combination and a controlled drip irrigation system in the joint corner. This new concept is independent of specific coating systems and minimizes the variability in testing due to long dry periods under certain climatic conditions.
J Van Acker, M Stevens
Accelerated testing for out of ground contact using natural biological preconditioning
1996 - IRG/WP 96-20088
Small blocks made of Scots pine sapwood were treated, buried in vermiculite and exposed to natural microbial colonisation during outdoor exposure prior to laboratory decay testing. Periodic microbial isolations, moisture content, permeability and weight loss tests were also conducted. Bacteria and moulds colonised the vermiculite and miniblocks well. Aureobasidium pullulans was common on TnBTO treatments. Basidiomycetes were isolated from the control miniblocks at 3 months. Controls showed slightly increased permeability compared with treated samples after 1 month. At 3 months, controls, all TnBTO treated blocks and the lower retentions of DDAC showed permeability increases. Weight loss in the field was low up to three months, even in the controls (3.5%). Agar block trials with no natural pre conditioning showed all preservative treatments were effective, but, after only 1 month's field exposure the lowest retentions no longer provided adequate protection. Further studies are in progress.
S Molnar, D J Dickinson, R J Murphy
Accelerated testing for out of ground contact using natural biological preconditioning: Part 2
1997 - IRG/WP 97-20108
Small blocks of scots pine sapwood were treated, buried in vermiculite and exposed to natural microbial colonisation during outdoor exposure prior to laboratory decay testing. An EN 84-type leach trial was carried out on unexposed samples. Periodic microbial isolations, moisture content, permeability and weight loss tests were also conducted. The experiment ran for 12 months. The colonisation of the miniblocks by micro-organisms was rapid and different patterns of colonisation were observed for differently treated miniblocks. The dominant organisms throughout were Alternaria sp., Fusarium sp., Curvularia sp., Aureobasidium pullulans, Phialophora sp. and bacteria. Weight losses of 10% occurred in the field by 12 months with untreated samples. DDAC- and TnBTO-treated miniblocks (at the recommended commercial retention) had weight losses of 7% and 8% respectively. ACQ treated samples at this retention had the lowest weight losses at only 1.5%. Of the treated samples, TnBTO-treated blocks had the most rapid rate of weight loss and also the fastest increase in permeability. TnBTO-and DDAC- treated samples had equivalent final permeabilities, at double the value of the ACQ-treated blocks. The decay trial indicated that this natural pre-exposure method was very severe with reduced performance of all treatments in the monoculture Basidiomycete tests after 12 months of pre-exposure. The comparative leaching trial showed that the failure of the preservatives was not due only to severe leaching in the test system. The white rot decay test indicated that at all retentions TnBTO- and DDAC-treated miniblocks had reached over 3% weight loss by 3 months pre-exposure but for ACQ this weight loss was not reached until 12 months. In the brown rot test at all retentions of TnBTO and ACQ weight losses of over 3% were reached by 3 months and for DDAC by 6 months.
S Molnar, D J Dickinson, R J Murphy
Some Experiences with Stake Tests at BAM Test Fields and in the BAM Fungus Cellar
Part 1: Comparison of Results of Visual Assessments and Determinations of Static Moduli of Elasticity (MOE)
2005 - IRG/WP 05-20319
With examples of routine in-ground stake tests differences are shown in the performance of wood preservatives at the BAM test fields Lehre and Horstwalde and in the BAM fungus cellar. Signs of attack of micro-organisms were assessed visually according to EN 252. Periodical determinations of static moduli of elasticity (MOE) revealed the influence of the attack on the elastic properties of the wood specimens. The course of visible signs of attack and the residual MOE corresponded sufficiently in the fungus cellar. At comparable decrease rates of the MOE the visible signs of fungal attack developed slower at the test fields than in the fungus cellar. The stake dimensions distinctly influenced the accelerating effect of the fungus cellar.
M Grinda, S Göller
L-joint based testing for service life prediction of exterior plywood in out of ground contact conditions
2006 - IRG/WP 06-20342
Good biological performance of several plywood types in exterior conditions is most probably related to altered wood moisture behaviour compared to solid wood. Therefore a test set up was developed, using EN 330 L-joint testing methodology, to facilitate differentiation of plywood for exterior applications. The proposed test set up is an adaptation of an accelerated L-joint method introduced by Van Acker and Stevens (2003). Regular L-joints are used to expose plywood specimens as an infill window system. The L-joints simulate bottom corners of a low quality joinery unit. Accelerated testing is based on a moistening device using a drip irrigation system feeding a horticultural rock wool sponge as wetting agent. This keeps the lower corner of the plywood sample wet and creates a moisture gradient in the panel. The specimens are inclined for 10 degrees, the face veneer of the plywood is facing south and inclined 45°. The newly developed exposure method is intended to be severe and acts as a simulation of a worst case situation. The accelerated weathering makes differentiation among several plywood products possible after only one year of outdoor exposure. Visual appreciation of the tested plywood, mass loss measurements, alterations in moisture absorption and desorption patterns and isolations of fungi present on the samples help to rank plywood in view of fit for purpose for use class 3 exposure conditions.
J De Smet, I De Windt, J Van Acker
Accelerated Above-ground Testing of Wood Preservatives
2007 - IRG/WP 07-20358
The Canadian wood preservation industry is interested the introduction of new preservative formulations, some of which are intended only for above ground uses. Canada’s Pest Management Regulatory Agency requires data from field tests under Canadian conditions but these can take many years to generate results. Forintek has therefore developed an accelerated above ground test, under contract to a variety of clients. This paper focuses on the test method and provides examples of results on four formulations tested for one anonymous client. Short lengths of treated and untreated nominal 2x6s were supported on stainless steel screws and intermittently sprayed with deionised water from above. All the test material was exposed to spores of Gleophyllum. sepiarium and Oligoporus placentus from fruitbodies grown on Petri dishes that were suspended from the ceiling and to spores from outside air introduced at intervals via a fan. In addition, half of the boards were exposed to mycelial colonization from wood blocks infected with G. sepiarium. The test material was evaluated using the AWPA 10-0 rating system. Six-month data from this new accelerated above-ground test method suggest that it will be capable of discriminating between treatments that may be resistant only to spore germination and those that are resistant to both spores and mycelium.
P I Morris, S McFarling