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Methodology challenges in developing a transfer of natural durability from sawmill residues, illustrated by experiences with white cypress (Callitris glaucophylla)
2000 - IRG/WP 00-20203
The transfer of durability-conferring extractives from durable to non-durable wood has been accomplished often, but usually as an educational exercise rather than as a commercially oriented process. In the latter environment, many factors previously overlooked become vitally important. How to study them, in the absence of well-developed methodology and given the shorter timeframes being demanded by industry research funding organisations, presents real challenges. These challenges will be illustrated by experiences with the development of such a process for the 'waste' durability components of white cypress. Factors to be considered include: identification of active components; quantification of their individual and collective activities against target organisms; optimisation of source material handling, storage and extraction techniques; extract standardisation and batch-to-batch reproducibility; compatible yet cost-effective carriers for the actives into treated wood; effects on durability and other wood properties such as strength and handling safety; regulatory obstacles including acceptance into wood preservation standards; and quality control methods for penetration and retention of the treated product.
M J Kennedy, M A Powell


Regulatory and Consumer Challenges Facing Timber Preservation and Durability Interests in New Zealand and Australia
2003 - IRG/WP 03-20282
Timber preservation and durability interests in Australia and New Zealand are facing many challenges and threats arising from regulation and standards changes, to direct competition from competitive materials producers. Industry can address these challenges by pro-active initiation of sound, holistic, research, that addresses the performance needs of the regulators and specifiers and the expectations of consumers. Opportunities do exist for producers of treated timber particularly related to termite management, CCA alternatives and bushfire protection.
C MacKenzie


Wood preservation research in Tanzania: Priorities and challenges
1988 - IRG/WP 3462
Tanzania provides some of the highest rates of wood deterioration in service leading to alarming economic losses and yet no serious concern is shown in search for solutions to the problem. The paper attempts to point out some of the priority areas in the field of wood preservation research that demand urgent attention if timber is to be used judiciously in this country. An account is given of the major constraints in Tanzania that are hindering progress in the field. The report ends with some suggestions on how to benefit the country by improving this research sector.
K K Murira, R Cockcroft


Impact of climate change on wood deterioration - Challenges and solutions for cultural heritage
2010 - IRG/WP 10-20441
Deterioration of wood in cultural assets follows the same physiological mechanisms as in modern structures. Therefore rules and data for prediction of service life derived from old wooden structures can be used to model the service life of recent wooden structures and vice versa. The latter is done in this paper: From experimental test set ups in the field spread over Europe, climatic data, wood temperature, wood moisture content, and decay rates recorded for several years were correlated and used for mathematic modelling of decay. On that data basis a first attempt is made to quantify the influence of global warming on wood decay rates for different regions and scenarios, valid for both: wood in modern and historic structures. Against this background conservation of cultural heritage is increasingly challenging and methods are sought to allow historic structures to survive without severe modifications in design, but also with limited use of preservatives. How moisture monitoring can contribute to this purpose is shown on the example of the Echo pavilion in Maksimir Park, Zagreb, Croatia.
C Brischke, A O Rapp, M Hasan, R Despot


Challenges and new developments in testing electro osmotic pulsing technology (PLEOT) by means of conventional laboratory methods
2011 - IRG/WP 11-40555
A new wood protection system, electro-osmotic pulsing technology, called PLEOT, is tested in lab trials using different test setup. The technology is tested on Scots pine sapwood and beech wood samples exposed to brown- and white rot fungi. Mass loss and moisture content is calculated after testing and a chitin analysis are performed on the sample powder. Two different electrodes are used in order to connect PLEOT to the wood samples. The results show that PLEOT fully protects Scots pine sapwood samples in a miniblock test exposed to Coniophora puteana and Trametes versicolor using conductive polymer as electrodes in laboratory trials. Scots pine sapwood samples connected by using carbon fiber electrodes show reduced mass loss after 16 weeks of exposure to both white- and brown rot when PLEOT is installed. The analysis of chitin after exposure to fungi verifies the results on mass loss. A comparable amount of chitin can be found in all three parts of PLEOT-protected and untreated wood samples. Fungal degradation after several weeks of colonization of untreated samples could be stopped in some cases Carbon fiber electrodes fail on several cases whereas the conductive polymer electrodes show good results and is going to be used in future trials. Wood moisture content is lower of PLEOT-protected wood samples after basidiomycete test compared to untreated samples. However, the wood moisture content of PLEOT-protected samples is not below an unfavorable amount for fungal attack.
A Treu, E Larnøy


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


The potential and the challenges of acetylated wood in timber bridges - experiences from an ongoing project
2017 - IRG/WP 17-40792
Acetylated wood is known to be a durable and dimensional stable alternative for high performance materials, and has high potential for exterior timber structures. Research has shown that acetylated wood can be effectively bonded by various adhesive types. However, one of the most common used adhesives for timber constructions, Melamine Urea Formaldehyde (MUF), shows a high degree of delamination of the bond line in acetylated wood. A Norwegian project is investigating the use of glued acetylated wood (GlAceWood) for load-bearing constructions for application in service class 3. Poor wettability and remaining free acetic acid from the modification process influence the bonding to various degrees. The project aims to improve the bonding properties of acetylated softwood and hardwood by manipulating a MUF-based adhesive system.
A Treu, R Bredesen, F Bongers