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Termite Resistant Properties of Wood and Natural Fiber Plastic Composites - AWPA E1 Test Data
2009 - IRG/WP 09-40466
This paper deals with resistance properties of wood plastic composites against Formosan Subterranean Termites (FSTs) based on the AWPA E1 test standard. Sixteen laboratory WPC formulations, four WPC commercial materials, and southern pine (Pinus sp.) wood control were tested for termite mortality, sample weight loss, and sample damage rating. The results show that FSTs did attack WPC products in the laboratory setting. The test was sensitive enough to demonstrate the effect of chemical treatment and type of surface (as-extruded exterior surface versus machined interior surface) on termite resistance. The type of plastics (e.g., HDPE vs PVC, and virgin vs recycled) and fibers (wood, bamboo, and bagasse) was less important, compared to wood fiber loading level and particle size. There was a large difference in damage mode and degree of damage from as-extruded exterior surface and machined interior surface of WPC. Commercial WPC was subjected to more termite attack from the exposed interior surfaces. An effective chemical treatment should prevent termite attack on both types of surfaces for WPC.
Q Wu, T Shupe, J Curole, K Ragon, M Voitier, M Freeman, D Ring

Lab-scale termite damage synthesis using least squares generative adversarial networks
2020 - IRG/WP 20-20674
This manuscript investigated the feasibility of least squares generative adversarial networks (LSGAN) to generate synthetic images of lab-scale termite damage based on AWPA E1 standard, to push machine-learning forward into wood science field and to ameliorate the lack of a termite damage dataset. We leveraged LSGAN to learn the distribution of 203 uniquely termite damaged samples from previous experiments. Our novel approach generated 256 x 256 pixels images with realistic and meaningful details. However, checkerboard artifacts were generated. The Fréchet Inception Distance (FID) was calculated and achieved averaged value below 25. This approach could be used to enhance previously done image classification model on termite damage severity. Future research will explore using GAN generated images to augment small datasets of real images and quantify any increases of image classification robustness.
D J V Lopes

Wood preservation in the USA
1982 - IRG/WP 3215
This report is a comprehensive survey of the status of the wood preservation field in the U.S.A. at the start of the 1980s. The importance of wood preservation is discussed and its industry described. Various statistics and analyses regarding the use of treated wood have been compiled. Both pressure and non-pressure applications have been covered, as well as remedial treatments and pest control operations. A list of American organizations concerned with wood preservation have been included, together with the various research laboratories which are studying the biodeterioration of wood and its protection. Information is given on the standards and specifications which are in current use. The report, which is fully referenced, ends by suggesting possible future trends for wood preservation in the U.S.A.
D D Nicholas, R Cockcroft

Soil blocks versus field test for evaluating and standardizing wood preservatives: A commercial view
1994 - IRG/WP 94-20024
On the basis of technical considerations, experience, costs and applicability, the author concludes that the soil block test and other laboratory tests have little meaning in a wood preservative standardization process and almost no merit in the commercialization of a wood preservative system. Field tests at sites known to be aggressive to preservative treated wood are strongly recommended.
W S McNamara

Climate indices at work: Above ground decay L-joint tests (EN 330 and AWPA E9) at two sites 12000 km apart and with Scheffer climate indices of 60-65 and 300-330
1996 - IRG/WP 96-20095
Matched sets of Scots pine sapwood (Pinus sylvestris) L-joints were exposed above ground at two field sites for approximately five years. One site, at Garston, Watford, UK has a climate index between 60 and 65 while the other, close to Hilo, HI, USA has an index between 300 and 330. The joints were treated with a range of organic solvent treatments applied either by three minute dip immersion or by double vacuum. Untreated joints were installed at each site as control material. All samples were assessed at approximately annual intervals at both sites. After five years, decay at the Hilo site is well advanced with failure apparent in many joints, both untreated and treated. As would be expected given the climatic differences, decay at the Garston site has progressed more slowly than in Hilo. Differentiation in treatment performance was apparent after one year's exposure in Hilo with similar differentiation becoming apparent after five years' exposure in Garston. This acceleration correlates well with the difference in Climate Index for the two sites as calculated using the Scheffer method. Encouragingly, the performance ranking of the different treatments at the two sites was very similar. The results of this test suggest that the concept of using high decay hazard sites for field testing of treated wood products for use in above ground situations can provide meaningful results in a short period, and may offer a timely and realistic alternative to relative preservative testing to that achieved in laboratory test regimes. The results also show that above ground field testing at both of the sites included provide valuable information on preservative performance, and this information is likely to provide a greater degree of realism than is possible using pure culture laboratory test procedures.
A F Preston, K J Archer, D M Roberts, J K Carey, A F Bravery

A critical review of the AWPA standard method (M12-72) for laboratory evaluation to determine resistance to subterranean termites
1986 - IRG/WP 1298
The American Wood Preservers' Association standard (M12-72) for evaluation of candidate wood preservatives against subterranean termites is reviewed and suggestions for revision are made. The most serious flaws in the current test procedure involve a failure to recognize inter- and intraspecific variation and a lack of quantification of test results.
J P La Fage, M Jones

International standards can we make them simple?
1996 - IRG/WP 96-20092
The earth is round and therefore limited in space. A consequence is that we - earthlings - are convicted to mutual understanding with a basic need to pay attention to others. Leading countries have been developing standards for years (i.e. USA/CANADA - AUSTRALIA/NEW ZEALAND - SOUTH AFRICA - EUROPE). They are keen and proud to argue on their peculiarities and advantages. A survey of the various schemes, procedures and criteria suggests a good consensus on the basics, with a need to classify specificities and allow local application. Europeans are stretching out their hands towards their colleagues to harmonize hazard classification; climatic conditions and levels of performance is also proposed to harmonize prescription worldwide.
G Ozanne

Protection of wood blocks treated with Trichoderma isolates selected on the basis of preliminary agar screening studies
1996 - IRG/WP 96-10154
Previously reported results of agar interaction screening studies for biocontrol agents of wood decay basidiomycetes showed two Trichoderma viride isolates, killed 16 of 19 target fungi (Tucker and Bruce, 1995). Testing of these isolates in wood was required to assess their performance at preventing decay of wood blocks. Standard testing of chemical wood preservatives is used to determine the toxic concentrations of preservative required to protect the wood against decay by basidiomycetes. As no ratified standards for testing biocontrol agents exist, two amended wood block testing standards were used to assess the two most effective Trichoderma isolates selected on the basis of preliminary agar screening studies. An agar based system similar to European Standard EN 113 (1980) and a soil block test based on the AWPA Standard 1413 (1977) were used with Scots pine and Sitka spruce pre treated with Trichoderma. Results indicated that wood blocks treated with Trichoderma isolates (T60) and (T110) were completely protected against decay by all the basidiomycetes tested irrespective of form of inoculum used (spores or mycelium) or timber species. Implications of the results for the use of agar plate interaction studies for screening biocontrol agents for subsequent use in wood block testing are discussed.
E J B Tucker, A Bruce, H J Staines

Soft rot
1978 - IRG/WP 179
Soft rot decay of treated wood is examined with special reference to hardwoods treated with CCA. Factors which adversely affect the chances of protection of hardwoods against soft rot are discussed. The ratio of the volume of the fibre cell wall to the volume of the fibre lumen is presented as a major factor influencing final preservative concentration in the fibre cell wall, the major strength contributing unit in wood. It is proposed that hardwoods are not necessarily more susceptible to soft rot than are conifers and that 0.2% Cu.wt/wt on gross wood will give control of soft rot in permeable hardwoods. Present and potential soft rot problems of treated conifers in North America are examined.
C R Levy

Chromated copper arsenate preservative treatment of hardwoods. Part 2: leaching performance of seven North American hardwoods
1997 - IRG/WP 97-30132
Seven North American hardwood species were treated with 2% CCA-C solution and fixed at temperatures of 21°C and 50°C and conditions of high relative humidity (95%) as described in Part 1 of this presentation. Red pine (Pinus resinosa) was included as a softwood for comparison. Adequately fixed wood blocks (99.9% chromium fixation) were exposed to leaching tests according to AWPA E11-87 test. Particularly high leaching losses were determined for red oak, red maple and beech.. In the case of red oak all three elements were leached in high quantities, while from red maple and beech higher arsenic leaching occurred. Higher leaching of arsenic was observed in those red maple blocks that fixed the fastest. Leaching losses from aspen, basswood and yellow poplar were low and comparable for both fixation temperatures. Very low leaching of arsenic from aspen and yellow poplar was observed in all series of experiments. Leaching results obtained confirmed the validity of the division of the examined hardwoods into three groups according to the CCA fixation and leaching results: fast fixing/high leaching group (beech, red oak and red maple), intermediate fixation rate and leaching amount (white birch and red pine) and slow fixing and low leaching group (aspen, yellow poplar and basswood).
T Stevanovic-Janezic, P A Cooper, Y T Ung

International standards - can we make them simple? Stage 2: Reflection arising from the discussion at IRG 27
1996 - IRG/WP 96-20103
For the purpose of the ISO FAST TRACK project on preventive wood protection and durability, one shall refer to the 3 following stages: Hazards: (for wood in service), a review of biological agencies defining the scope; Exposure: a review of local, geographical parameters influencing the virulence of biological agencies towards wood in service (i.e climate indexes); Risks: as a combination of hazards and exposure. Risks vary considerably with exposure for an occurring biological agency (hazard) and can only be managed locally on the basis of local assessment. Local levels of prescription, associated to service life, need be listed to harmonize prescriber procedures. They may be recorded as informative annexes on the basis of local declarations. How can we make them simple ? A proposal: 1 standard 4 chapters informative annexes: Part 1: Wood biological hazards Inventory Part 2: Wood protection parameters Inventory Part 3: Wood preservative specifications Part 4: Treated wood specifications Insertion of TC 38 standards: Part 1, annex 1 = EN 335 Part 2, annex 1 = EN 350 + EN 460 Part 3 = EN 599 Part 4 = EN 351
G Ozanne

International co-operation in wood preservation research
1979 - IRG/WP 3145
If one searched the literature, one could find many examples of international co-operation in the field of research in wood preservation. For example, individual workers in different countries in Europe have got together and made replicate tests with both fungi and insects on various preservatives of common interest and their results have been published. Much co-operation has not had its results published. Over the years, for example, at the old Forest Products Research Laboratory, overseas countries have sent both their own timbers and their own students to study these where all the facilities have been available, and this sort of exercise has gone on in many lands. There have been exchange visits of research workers from country to country, but these are all examples of individual items of co-operation. In this talk, however, we will have to confine our discussion to organized international co-operation. I will give some remarks about the largest organization in this field, viz. the International Research Group on Wood Preservation (IRG) at the end.
R Cockcroft

El Rol de la AWPA en las Normas y Códigos Nacionales e Internacionales
2008 - IRG/WP 08-20389
AWPA Standards for treated wood products are recognized around the World in building codes and architectural specifications. Standardization is important in the global marketplace because it leads to increased safety, reliability, and efficiency. Consumers have a profound awareness of and preference for standardized products, even though businesses sometimes ignore them. Historically, market failure and excessive government intervention may occur after companies withdraw from the standardization process. The reduction of trade barriers throughout the Americas has created an opportunity for harmonized standardization of treated wood products and practices for North, Central and South America, leading to reduced market fragmentation and increased consumer confidence.
C McCown

Prevelence of termite infestation and wood preferences in Pakistan
2009 - IRG/WP 09-10695
In order to know about prevalence of termite infestation in Pakistan, A study was carried out to know the intensity of infestation of different species of termites to different types of woods used in buildings as well as in the forests. Heterotermes indicola was the most notorious species of termite present in buildings, grounds throughout the year while Odontotermes obesus was most common in forests. Of the different kinds of woods used in buildings, Sagwan was reported to be highly resistant in buildings. As far as public perception of termites is concerned, only 2% of the people have the knowledge about termite and its proper treatment. In the second part of study, 10 heartwoods of local timbers used in Pakistan were evaluated for their ability to resist termite damage by Heterotermes indicola. Woods were evaluated for forced feeding and not forced feeding bioassays in the laboratory as well in the field for 4- weeks. Tested woods were evaluated for Mean visual ratings, Mean wood mass loss and Mean % mass loss. At the end of experiment, in the field for H. indicola, the wood specimens were arranged in the following descending order of preference Ficus religiosa(FR)< Albizzia lebbeck (AL) < Eucalyptus citriodora(EC) < Heterophragma adenophyllum (HA) < Terminalia arjuna (TA) < Melia azedarach ( MA) < Alstonia scholaris (AS) < Abies pindrow (AP) < Pinus wallichiana (PW) < Erythrina suberosa (ES). In laboratory experiments, both by choice and No choice feeding, the woods were arranged the following order of preference Heterophragma adenophyllum (HA)< Ficus religiosa(FR)< Terminalia arjuna (TA)< Albizzia lebbeck(AL) < Pinus wallichiana (PW) < Alstonia scholaris (AS)< Erythrina suberosa (ES)< Eucalyptus citriodora (EC) < Abies pindrow (AP) < Melia azedarach ( MA).
F Manzoor, S Asma Malik

Component leaching from CCA, ACQ and a micronized copper quat (MCQ) system as affected by leaching protocol
2009 - IRG/WP 09-50261
Leaching results for Cu, Cr and As (CCA) and Cu (ACQ and MCQ) from southern pine are compared for laboratory tests (AWPA E11, and draft OECD methods I and II) and natural weathering of horizontally and vertically oriented lumber samples over two seasons. This paper expands on results and comparison of results presented at the IRG regional meeting in Costa Rica in Dec 2008 (Cooper and Ung 2008) and provides direct comparisons among leaching results for various laboratory and natural weathering conditions. It includes leaching of As and Cr components of CCA and estimates of cumulative DDACb leaching from ACQ and MCQ samples exposed to natural weathering.
P A Cooper, Y T Ung

Durability of Furfurylated Wood – Results from Laboratory and Field Tests in the Ecobinders project
2012 - IRG/WP 12-40602
Within the EU project Ecobinders, laboratory tests were performed with furfurylated wood produced in semi-industrial scale in the factory of Kebony ASA. Field trials in Horizontal double layer decks and in-ground of transmission poles were also started. Four wood species, Southern yellow pine (SYP), maple, beech and aspen were treated to two treatment levels by using two impregnating liquids with different furfuryl alcohol content. Full length Scots pine poles were only treated with the higher furfuryl alcohol concentration treating liquid. SYP and beech samples were tested according to EN113 and maple and aspen samples according to the corresponding American test, AWPA E10. All wood species except Scots pine, at two treatment levels were installed in a HDL deck and the poles in ground with a creosoted pole as reference. The laboratory tests with three test fungi showed very consistent results. The low FA-content treating liquid (FA40) resulted in durability class 2-3 and the higher FA-content treating liquid (FA70) resulted in Durability class 1. After these tests Kebony ASA decided to switch from FA40 treating liquid to FA70 treating liquid in all of their production and is still using this mix in the production. The field trials were started in 2006 and after 5 years all 6 furfurylated poles (WPG=40 in the sapwood zone) were sound, which is, however, also the case for the creosoted pole reference. In the HDL test all furfurylated test stakes are more or less sound, whereas the controls are moderately to severely decayed.
M Westin

Laboratory Study of Relative Leachability of Chromated Copper Arsenate Preservative from Treated Woods among Soil Types of Sarawak
2014 - IRG/WP 14-50307
Wood and soils are important natural resources from the environment and serves mankind well respectively as structural materials and natural platform erecting such materials. With shortfalls of naturally durable timber species for protected in-ground uses under Malaysian environments, Chromated Copper Arsenate (CCA) treated woods are widely used instead, incurring serious potential threats of preservative leaching from wood to the surrounding soil environment. This paper highlights a laboratory study into the relationship of the physical and chemical properties of main soil types of Sarawak, Malaysia, i.e. red-yellow podzolic, grey-white podzolic, gley, podzols and peat soil, on CCA leaching resistance or susceptibility from three treated wood species rubberwood sapwood (Hevea brasiliensis), engkabang undifferentiated wood (Shorea macrophylla) and mangium heartwood (Acacia mangium) materials in shallow soil-burial according to the AWPA E20-04 laboratory test methodology. Statistically significant (P<0.05) variations were detected between wood species as well as leaching of CCA and its component heavy metals. Engkabang wood yielded the highest overall mean CCA losses [620 ppm (44.0 %)] while A. mangium heartwood had the least mean CCA metal losses [374 ppm (26.0 %)] among the treated woods. Arsenic showed the highest deposition [757 ppm (53.0 %)] compared with chromium [370 ppm (26.0 %)] and copper [295 ppm (21.0 %)] among different soils. Overall, leaching of Cu, Cr and As was higher in more acidic soils, while soil macronutrient (N, P, Ca and Mg), micronutrient (Zn, Mn) levels, pH, cation exchange capacity, organic matter content and soil microbial count have significant (P< 0.05) negative correlations to leaching losses of one or all of Cu, Cr and As.
A H H Wong, P K F Chong

Overview of the treated wood quality control program in the United States with the recent challenges and advances
2017 - IRG/WP 17-20616
In the past two decades, there have been significant and rapid changes in wood protection technologies for residential applications which have moved away from long established heavy duty metal oxide based products such as chromated copper arsenate (CCA). The successor generation of wood protection systems usually contain copper as the primary biocide, in combination with carbon-based co-biocides such as quaternary ammonium compounds (Quat), and/or triazoles (Tebuconazole and/or Propiconazole). The most recent developments have given rise to even more complicated combinations including multiple carbon-based biocides formulated in the form of emulsions or dispersions with or without water repellents or polymers aiming to minimize the use of heavy metals as well as provide improvement in wood dimensional stability and surface weathering performance. Also, long developed non-biocidal wood modification treatments, such as acetylation, thermal modification, furfurylation and hydrocarbon wax/oil treated wood have finally gained more commercial traction in the market place, especially in Europe. These new developments have challenged the industry to develop and use appropriate methods in order to meet the quality control (QC) standards and requirements in respect to concentration of treatment solutions, as well as chemical retention and penetration in treated wood. In the US, the QC system for treated wood product includes three key elements: treating plant internal QC for treating solution, treated wood, and treatment process; QC assistance and monitoring by the chemical/technological suppliers for their customers, and QC inspection by third-party inspection agencies. The enforcement of the QC standards through this comprehensive system is essential to ensure the performance of the treated wood products, the validity of product warranty program, and ultimately for the protection of consumers and the public. This paper overviews the US’s current QC standards and procedures used by treating plants, suppliers and independent inspection agencies. The chemistry challenges with the recent developments of multi-component systems and complex wood protection technologies, and their impacts on quality control methods are also discussed. Case studies have been used to illustrate how some of these challenges can and have been successfully addressed.
L Jin

Post-layup protection of mass timber elements in above ground protected exposures: 2-year results
2022 - IRG/WP 22-30766
Mass timber has seen increased use as a building material for low and mid-rise construction in recent decades. The durability of mass timber elements has not been fully examined and the effects of wood destroying organisms on this these materials merits attention. The effectiveness of currently labeled soil termiticides and passively applied biocides at post-construction or as remedial agents needs to be evaluated for mass timber used in structures, particularly in areas with elevated risk of termite attack. The ability of soil insecticidal drenches or spray-on insecticide/fungicide treatments for protecting mass timber in service was assessed with a modified AWPA Standard E21 above-ground test using three ply Douglas-fir or southern pine cross-laminated timber as well as Douglas-fir mass plywood panels. Samples of each material (305 x 102 x 102 mm) were installed in an above ground protected test at the Harrison Experimental Forest (HEF) (Saucier, Mississippi) in September, 2019. Six replicates of five treatments including soil termiticide, no treatment, spray-on borate at initiation, borate rods and remedial treatment, using spray on borate of attacked material after two years, were tested. Samples were left undisturbed for two years and then examined and rated. Near surface moisture content increased to levels approaching the fiber saturation point over the two-year non-disturbance period. Untreated control samples were attacked by both decay fungi and termites. Samples treated with borates at test initiation showed limited decay or termite attack. Soil termiticide treated plots showed no sign of termite attack, but some samples had heavy decay compared to non-soil termiticide treated plots.
M E Mankowski, T G Shelton, G T Kirker, J J Morrell