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Study of weathering Characteristics in Profiled and Treated Deck Boards
2014 - IRG/WP 14-40680
Wood exposed outdoors to repeated wetting and drying develops surface checks. Excessive checking of wooden deck boards has been a major source of dissatisfaction to consumers. In this study, Southern pine (Pinus sp.) deck boards were machined to flat (control) and ribbed surface profiles. The specimens were treated with aqueous formulations of 4,5-dichloro-2-N-octyl-4-isothiazolin-3-one (EL2) and amine copper azole (CA-C) using a vacuum/pressure method. Boards were exposed to accelerated weathering for 576 h (24 days). The number, length and width of checks that developed in boards and average amount of cupping, twist and bowing in each test board were quantified after weathering. The results of statistical analysis showed all of the preservative-treated ribbed decking samples had a lower average number of checks compared to end matched flat samples. Checks were also shorter and narrower in the profiled deck boards than in the unprofiled specimens. Furthermore, the lowest amount of checking, cupping, twist and bowing was observed for specimens profiled and treated with the EL2.
M Akhtari, D Nicholas, L Sites

Nondestructive Evaluation of Oriented Strand Board Exposed to Decay Fungi
2002 - IRG/WP 02-20243
Stress wave nondestructive evaluation (NDE) technologies are being used in our laboratory to evaluate the performance properties of engineered wood. These techniques have proven useful in the inspection of timber structures to locate internal voids and decayed or deteriorated areas in large timbers. But no information exists concerning NDE and important properties of wood composites exposed to decay fungi. For our pilot study on several types of wood composites, we examined the relationship between nondestructive stress wave transmission, decay rate and the bending properties of OSB exposed to the brown-rot fungus, Gloeophyllum trabeum (MAD-617). The following measurements were taken: stress wave transmission time (pulse echo test method), static bending test (ASTM D3043-95), and decay (expressed as percent weight). Stress wave measurements correlated with strength loss and with increasing rate of fungal decay. Stress wave NDE has great potential as a method for inspection of wood composite load-bearing (in-service) structures, detection of decay in laboratory tests, assessment of chemical additives to improve wood composite durability, and prediction of long term composite performance.
B Illman, V W Yang, R J Ross, W J Nelson

Wood preservatives: Field tests out of ground contact. Brief survey of principles and methodology
1976 - IRG/WP 269
This paper contains the following spots: 1.: The general need for field tests. 2.: Interests and limits of field tests in ground contact. 3.: Various methods in use for out-of-ground contact field tests. 4.: Fungal cellar tests are they an alternative to above-ground decay exposure tests? 5.: Conclusions.
M Fougerousse

Mycological testing of plywood and board materials. Part 1: Review of information supplied by IRG members
1978 - IRG/WP 284
In December 1975 IRG members were asked for published information, information of current work in progress and views on mycological test methods for board materials. The object was to stimulate discussion and possibly establish a joint research effort within IRG in order to establish a meaningful test with reproducible results.
C R Coggins

Results on termite resistance of building materials against Coptotermes formosanus by choice test
1998 - IRG/WP 98-10275
Various building materials, included wood species, wooden board materials, thermal insulation materials and fire-protection materials, were tested for grading of termite resistance against Coptotermes formosanus. The dimension of most specimens were 2x2x2cm3. Ten repeats were prepared. The specimens were put between Akamatsu sapwood control specimens on a laboratory cultured mound colony of termite, Coptotermes formosanus. After 1 month of attack to termite, the specimens were removed from the mound colony and cleaned up. Then these final mass were weighed. The grading of termite resistance was initially estimated by mass loss of specimens. This grading was corrected by visual observation. Japanese 3 domestic species, cypress pine, Alaska- ceder, kapur and mahogany were indicated rather high termite resistance. In the case of Siberian red pine and Gmelina, the valued of termite resistance were shown variable. Tropical species plywood, inorganic board and radiata pine MDF, were shown rather high termite resistance. Other board materials were shown rather less termite resistance. Most of commercial soft wood plywood and OSB were very sensible against termite. Most common thermal insulation materials in Japan were estimated very sensitive against termite. In the case of fire protection materials, expanded concrete was rather good against termite but plaster board was very sensible against termite.
K Suzuki, K Hagio

A note on testing the efficacy of wood preservatives above ground
1995 - IRG/WP 95-20078
A number of test methods have been used to evaluate the performance of wood preservatives in above ground situations. These have included EN 113 tests following natural exposure weathering (NEWT), L-joint or T-joint tests, lap-joint tests, and decking tests. A new test referred to as the A-frame test has been developed and is under evaluation. This is based on a sandwich-type test in which a thin (3.5 mm) sample is exposed outdoors between two untreated samples on a rack or A-frame. The advantages and disadvantages of these types of tests are discussed in a short note.
G R Williams, J A Drysdale, R F Fox

Contribution to the testing of wood based board material
1982 - IRG/WP 2176
R G Lea

Field testing of soil insecticides as termiticides
1986 - IRG/WP 1294
This paper reviews field methods used to evaluate soil insecticides as termiticides by the U.S. Department of Agriculture, Forest Service, Gulfport, Mississippi. Field tests are conducted on a minimum of five "nationwide sites" in the United States to determine the efficacy of chemicals in various soil types and against different termite species. Test results of selected insecticides are presented.
R H Beal

Use of the Pilodyn to assess deterioration of treated aspen waferboard after 30 months of outdoor exposure
1986 - IRG/WP 2254
Samples of preservative treated aspen waferboard exposed outdoors for 30 mo. were compared using pin penetrations of the 6 Joule Pilodyn. These results correlated well with rankings of treatment performance based on more laborious standard mechanical tests, and demonstrate the potential for use of the Pilodyn as a tool to evaluate wood composites in test exposures with minimal destruction.
E L Schmidt, M G Dietz

The effect of storage or simulated internal use on the durability of wood based panels to decay fungi
1997 - IRG/WP 97-20106
Wood based panels such as particleboard and medium density fibreboard are experiencing a steady increase in use, in areas from structural to decorative applications. Understanding the "natural" durability of these panel products against basidiomycete fungal decay is therefore of great importance. Various methods have been proposed or are under development to test the durability/susceptibility of various panel products to decay. Our research has shown that if the fungal exposure methods detailed in the current European pre-standard (DD-ENV 12038:1996) are used to test boards fresh from manufacture, the susceptibility ratings observed are significantly lowered by the buildup of inhibitory substances in the test vessels. The effects of storing the boards before testing, in order to remove this effect have been studied with repeat biological tests carried out at intervals of 6 months. Our results show that even after 6 months storage the effect is reduced but not totally removed. The time after manufacture and the storage conditions are clearly significant variables affecting the "durability" of test specimens taken from the boards and therefore the incorporation of an appropriate preconditioning stage into the test is essential so that the effect is avoided.
S F Curling, R J Murphy, J K Carey

Decay resistance of high performance biocomposites based on chemically modified fibres
1998 - IRG/WP 98-40120
Different partners within the framework of a European research project produced high performance biocomposites aiming at the utilisation of board materials as durable products both in dimensional and biological degrading circumstances. This paper summarises test data, which indicate the potential of board materials produced with modified fibre material. The chemical modifications applied cover a range of technologies, which were selected for scaling up experiments. Acetylation, as well as alternative methods like maleiation, phthalylation, succinylation, oxidation and silylation were investigated. Fibre source, density variation and the use of several types of glues were parameters of the total set-up. Basidiomycete testing was carried out using specific methodology for board materials elaborated in CEN standardisation committees.
V Rijckaert, J Van Acker, M Stevens

Biodegradation of acetylated southern pine and aspen composition boards
1994 - IRG/WP 94-40020
This objective of this study was to investigate the influence of the acetylation treated wood fiber, Phenol-formaldehyde resin content level, two wood fiber species, three fungi species on the dimensional stability and decay resistence of high density composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness and length changes and the decay resistance of the high density composition boards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Powell

Fungal colonization of CCA-treated decking
2003 - IRG/WP 03-10491
The identification of fungi isolated from CCA treated decking in Vancouver is reported. About two thousands locations were sampled from over sixty boards recovered from six decks. Wood chips from each location were placed onto four different types of media. Of the large number of isolates obtained, around 15% were obtained from the interior of the boards. The succession of colonization in CCA-treated decking; i.e. bacteria, mould, staining fungi, (soft-rot fungi), and basidiomycetes, was similar to that reported from untreated wood exposed above ground and from CCA treated wood in ground contact. The percent frequency of isolation around checks was higher than that from wood just below the treated surface. In the case of boards where decayed wood was observed during sampling, most decay was associated with checks. In this study, Gloeophyllum sepiarium and Gloeophyllum trabeum (tentatively identified) were the only decay basidiomycetes isolated from the inner wood of decayed decking. Other unidentified basidiomycetes were isolated from the treated surface of the boards, the check surfaces or the cut end of decking from both decayed and non-decayed boards.
S Choi, J N R Ruddick, P I Morris

The evaluation of the occurrence of soft rot in creosoted wooden poles
1988 - IRG/WP 1368
The occurrence of soft rot decay in creosoted wooden poles for overhead power lines was investigated by collection of field samples, their subsequent microscopic examination and statistical analysis of the data collected. Examination of samples collected from 296 poles revealed that approximately 15% of the pole population studied (Eastern Electricity Board) showed the presence of soft rot decay. Further, it was found that of undated poles, (those emplaced before 1953,) 17% displayed soft rot attack.
A Wylde, D J Dickinson

Health and safety aspects of the use of wood preservatives in Sweden
1977 - IRG/WP 396
The Act on products Hazardous to Health and to the Environment (Swedish Code of Statutes SFS 1973:329) came into force on 1st July 1973. The Act cancelled and superseded the Poison Act, the Pesticides Act and the PCB Act from 1962, 1962 and 1971 respectively. Regulations for the implementation of the Act are contained in the Ordinance on Products Hazardous to Health and to the Environment (SFS 1973:334) and also in an Amendment of the Ordinance (SFS 1973:1050). A comprehensive summary of the Act and the Ordinance prepared in common by the Swedish Ministries of Agriculture and Foreign Affairs has been deposited in the IRG/WP Secretariat. Much of the information given below as regards the Act is derived from this booklet.
B Henningsson

Treatment of wood-based panel products with volatile borate
1990 - IRG/WP 3616
The paper presents recent developments in the use of volatile borate esters for the preservative treatment of wood based board materials. Several advances on previous reports are discussed. In laboratory studies, treatment times of approximately ten minutes at 20°C on boards at equilibrium moisture content provided full penetration and retentions of 1% wt/wt boric acid. Biological tests have been conducted on a wide variety of boards treated by the vapour boron method. In all cases a retention of 0.7% wt/wt boric acid gave complete protection from decay. These results are considered with regard to parallel studies on solid wood by colleagues at the Forest Research Institute, Rotorua. The advantages of vapour boron treatment for wood based board materials are discussed.
P Turner, R J Murphy, D J Dickinson

Worldwide in-ground stake test of acetylated composite boards
1997 - IRG/WP 97-40088
Acetylated wood composite stakes are being tested in ground contact (graveyard test) in seven fields around the world. Three types of acetylated wood composites were prepared: spruce fiberboard in Sweden, aspen fiberboard in Madison and rubber wood particle board in Indonesia. Two levels of acetylation were used, a high level of ~20% acetyl content and a low level of 10% acetyl content. Control boards of unmodified wood fiber/particle were also included. Stakes for the in-ground testing were taken from the boards and the size of each stake was 5x30x1.25 cm3. The stakes were put out in four continents: one test field in USA, one in New Zealand, two in Indonesia and three in Sweden. After three years of testing, results show that acetylation of wood provides excellent protection against fungal attack and minimizes swelling.
R M Rowell, B S Dawson, Y S Hadi, D D Nicholas, T Nilsson, D V Plackett, R Simonson, M Westin

Performance of non-incised CCA-treated hem-fir decking
1993 - IRG/WP 93-40004
The question of what preservative penetration will provide an acceptable service life for treated wood in residential above-ground applications is topical in North American standards committees. Non-incised CCA-treated nominal 2 x 4 inch² hem-fir decking with penetrations close to the proposed CSA O80 2 decking standard of 80% over 5 mm, has remained without decay after 10 years exposure in south western British Columbia. Material with minimal preservative penetration showed early signs of decay. In contrast untreated unstained material had reached a rating of 1.1 on a 0 to 4 scale (0 = sound) with 12% of boards needing replacement. These results support consideration of a reduced penetration requirement in the standards for CCA treated decking.
P I Morris, J N R Ruddick

Properties of plywood and Oriented Strand Board manufactured with an organic insecticide incorporated in the adhesive formulation
2000 - IRG/WP 00-40174
The efficacy of Fipronil as an insecticide has been established by laboratory and field experiments and commercial use against a broad range of insect pests for various crops. It can be used by either foliar or soil application. Development is underway for the non-agricultural uses of fipronil. Research is ongoing for the control of ants, cockroaches, fleas, ticks, houseflies, mosquitoes, termites and other pests. Several countries in the world have experienced extensive termites damage. The protection of structural and non-structural cellulosic products against termites may be required in the near future. With the increase uses of wood composites in wide ranging applications, protection against termites will represent one of the criteria of material selection. Fipronil was added in the formulation of adhesive during the laboratory manufacture of plywood and oriented strand board. The average MOE and MOR from of plywood was about 1.1 to 1.2 million psi and 8000 to 9100 psi, respectively. Shear strength and wood failure varies from 191.6 to 239.9 psi and 73% to 92%, respectively. Analyses of variance showed that statistically there were no significant different of all properties tested between fipronil concentration (0 - 375 ppm) at 5% level. This study indicates that fipronil has no affect on MOE and MOR under bending regime, and on the shear strength and the wood failure. After 18 months above and ground contact exposure in Gainesville, Florida, a level of 150 to 200 ppm successfully control the termite attack.
D P Kamdem, J H Hope, A Jermannaud

Above-ground field tests undertaken in New Zealand
1995 - IRG/WP 95-20063
In addition to "standard" L-joints, above-ground test material exposed at the NZ FRI test site includes treated and untreated decking units, Y-joints, fence battens and weatherboards either with or without additional protection from surface coatings. The latter tests bridge the gap between "model" test assemblies, such as L-joints, and services tests. Most tests are of preservative-treated radiata pine using proprietary formulations which were approved for above ground use at the time when each test was established. Other tests are natural durability tests to determine the suitability of those species, in terms of durability and mechanical properties, for above ground use without preservative treatment. The first tests were established in 1952 and results from those and subsequent tests have been used during periodic amendments to NZ wood preservation standards and specifications. The purpose of the different tests is described as well as pertinent results from them to illustrate their value.
M E Hedley, D R Page, J B Foster, B E Patterson

Service life of pressure treated deckings of spruce in direct contact with the ground
1988 - IRG/WP 3463
For decking outdoors in Sweden, pressure treated Scots pine (Pinus sylvestris L.) is used, on account of its treatability. The feasibility of using instead the refractory Norway spruce (Picea abies Karst.) is tested in a field trial. The spruce decks were treated together with pine decks with an ordinary Bethell process. As yet, after more than four years of exposure, neither in the battens nor in the slats of the treated spruce decks any visible sign of decay has been observed. The status of the deckings is followed up with observations of the moisture content and with Pilodyn measurements of the depth of penetration of the striker pin. The pressure treated spruce material has a consistently lower moisture content and mostly also a lower penetration depth of the Pilodyn striker pin than other untreated material.
J B Boutelje, T Sebring

The possible role of mobile CCA components in preventing spore germination in checked surfaces, in treated wood exposed above ground
2001 - IRG/WP 01-30263
Untreated check surfaces are often exposed in CCA-treated lumber of refractory species used above ground since, during weathering, some checks develop beyond the preservative penetrated zone. However, decay is seldom observed in these checks even after many years of exposure. It is hypothesized that minor amounts of mobile CCA preservative components redistribute during weathering into checks, and that this 'surface treatment' prevents fungal spores washed into checks from germinating and causing decay. A substantial amount of copper was found on the exposed check and end-cut surface in exposed wood through the current research, and whether spores are prevented from germinating by this amount of chemical is being studied.
S Choi, J N R Ruddick, P I Morris

Premature failure of treated timber in wharfs in Papua New Guinea, attributed to defects in design
1991 - IRG/WP 4158
The performance of timber in wharfs in Papua New Guinea has been monitored for a number of years. Premature failure of wharf structures was found in many cases to be due to defects in design rather than ineffective preservative treatment. Above-water timbers were found to be prone to severe checking followed by decay. Protection for the end grain of pile tops and the limiting of radial checking in them was found to be vital. Removable metal caps and stout metal bands sized to give a snug fit around the circumference of the pile were found to give the best protection. Major areas of decay or marine borer attack were most common where other structures were attached to the piles in such a fashion that the "envelope" of treated sapwood was breached. In order for treated timber to perform satisfactorily in wharfs, care has to be taken at the design stage. Any post-treatment machining should be undertaken with suitable tools and remedial treatment or protective measures will be required. A list of recommendations for the use of treated timber in wharfs in the tropics is given, relating to the preparation of wood, the construction of the wharf and the protection of vulnerable parts of the installed wharf. The question of good and bad design, and its effect on service life of wharf timbers requires further investigation. The author requests colleagues with information relating to this to contact him.
S M Cragg

Characterization of checks and cracks on the surface of weathered wood
2000 - IRG/WP 00-40153
The surface roughness of unweathered and untreated pine; unweathered copper chromium arsenate type C (CCA) - treated pine; weathered CCA-treated pine; and weathered CCA-plus-water-repellent (WR) - treated pine was evaluated by a stylus tracing method. Surface roughness parameters Ra, Rz, Rmax, Rk, Rpk, and Rvk were measured. Ra, Rpk, and Rvk were the most appropriate parameters for describing modifications on the wood surface. Ratios of the roughness parameters of the exposed (top) and unexposed (bottom) surfaces of the untreated, CCA-treated, and CCA + WR - treated wood samples were used to estimate the extent of the weathering damage on the exposed surface. The parameter ratios for the top and bottom surface were used to estimate the extent of the damage created by rain and sunlight on each piece of wood. This study shows that the stylus technique is appropriate to estimate the number and size of checks and cracks on wood surfaces after weathering.
D P Kamdem, Jun Zhang

Effect of vapour boron treatment on mechanical properties of wood based board materials
1992 - IRG/WP 92-3727
The mechanical properties of Medium density fibre board, Chipboard and Oriented strand board were investigated after treatment to two retention levels of boric acid applied as a vapour phase system. A range of mechanical properties were investigated. The vapour boron treatment does not have any significant effect on most of the mechanical properties of the boards. The exception is a reduction in impact strength especially at the higher retention level.
R Hashim, D J Dickinson, R J Murphy, J Dinwoodie

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