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The use of zirconium as an inert fixative for borates in preservation
2001 - IRG/WP 01-30256
Stand-alone borates have been used in internal protected situations as wood preservatives for about 60 years. They have not been deemed acceptable for external situations because of their leaching characteristics. Work carried out to reduce the leachability of borates has been reviewed briefly here, and a specific fixation agent based on zirconium has been tested in standard leaching and decay tests. It was found that the performance of zirconium could be optimized for fixation at specific drying temperatures and at higher formulation pH. Using sufficient quantities of ammoniacal zirconium carbonate and potassium zirconium carbonate such formulations are then able to pass both Standard European and American Wood-Preservers' Association methods designed for testing exterior wood preservatives. Formulations based on borate with a zirconium additive are probably suitable for use in exterior above ground and possibly ground contact situations. As only initial indicative tests have been carried out so far, further testing with a range of wood destroying organisms and field tests should be carried out to evaluate this system further.
J D Lloyd, J L Fogel, A Vizel

Preservatives stains as exterior wood finishes
1977 - IRG/WP 389
For many years wood preservatives and paints have been used as the only treatment for exposed wood surfaces. Because of the inherent color of the preservatives, such as creosote, the wood surface was stained as well as protected from attack by micro-organisms. Paints protect surfaces from weathering, but recently, with an increased interest in maintaining the more natural appearance of exterior wood surfaces, painting is being replaced by staining. Stains have the advantages, in addition to preserving the natural wood appearance, that they do not peel, blister or crack, can be applied easily and renewed with little difficulty. The cost is less than that of paint, initially and over the life of the building. One of the major attractions for homes is that stains blend in with the environment. If the home owner desires a white exterior or bright colors, paint rather than a preservative stain must be used. Paints are more effective in protecting the wood from damage by sunlight and will avoid discoloration of the exterior surface resulting from the natural extractives present in wood. Special aluminium or stainless steel nails are not needed with paints, but are needed with stains. Preservative stains can be classified in various ways. Wood preservatives, such as creosote and pentachlorophenol, have been used for many years primarily for preventing deterioration caused by fungi, including fungus species which discolor and those that decay the wood. These compounds provided some degree of water repellency, but this was not a major objective in their use. Later, water repellents were added to the preservatives to reduce the rapid uptake of moisture and thus provide some dimensional stability to the product. More recently water solutions of inorganic salts have demonstrated that they provide protection to the wood, add color and are beneficial primary treatments if the wood surface is to be painted. Some of the water soluble formulations may provide some fire retardant properties as well. A common system of classification today includes three general types of natural finishes as follows: 1. water-repellent preservatives; 2. pigmented penetrating stains; 3. inorganic water soluble salts. It is possible to obtain a satisfactory exterior surface if no treatment is applied. Such an approach, however, is satisfactory only where the weather is not favorable for micro-organisms. If the fungi and other micro-organisms are allowed to develop, the coloring will be very nonuniform, the wood surface will deteriorate, and warping and the like will occur to excessive degrees. Thus in most environments one of the above systems must be used.
D W French

Exterior paint for the future - Will there be any dry-film preservatives left?
2017 - IRG/WP 17-50332
Wooden houses have a long tradition in several of the Nordic countries. Wood can be protected in various ways; constructional, chemically and by surface treatment. The use of various types of exterior paints as a surface treatment is a common way to prolong the durability of the wood. To further protect the painted surface against growth of fungi and algae, dry-film biocides remains an essential part of a high quality exterior paint. In Europe, the use of biocides is regulated by the Biocidal Products Regulation (BPR). Dry-film preservatives are just beginning to be evaluated, and already several of the well-known dry-film biocides face challenges with being approved under BPR. This paper will discuss the purpose of applying exterior paint(s), biological growth on painted facades, and the uncertain future of the dry-film biocides in Europe.
H Jensen, M Sandve, S M Lystvet

Danish wood preservatives approval system with special focus on assessment of the environmental risks associated with industrial wood preservatives
2001 - IRG/WP 01-50166-01
The following is a description of the procedure used by the Danish Environmental Protection Agency to assess the environmental risks associated with preservatives used in the pressure impregnation of wood. The risk assessment covers issues considered to be of significance for the environment and which are adequately documented so as to allow an assessment. Such issues are persistence and mobility in soils, bioaccumulation and the impact on aquatic and terrestrial organisms. Unless required in special circumstances, the assessment does not apply to birds and mammals as the normal use of preservative treated wood is not expected to involve any noteworthy exposure of these groups. Approval of wood preservatives will be based on a general assessment of the environmental risk associated with the normal use of wood treated with the preservative in a realistic worst case situation. The assessment may address other aspects such as disposal and total life cycle.
J Larsen

Finishes for outdoor timbers
1975 - IRG/WP 378

Wood preservation in Poland
2004 - IRG/WP 04-30362
Dynamic growth of market demand for wooden elements and articles, generated in Poland increase of interest in industrial preservation. Today, Poland is a substantial producer and exporter of wood made products. Majority of exported wood - approximately 70% - is scotch pine (Pinus silvestris L.), which, due to its natural durability, requires preservation.
A Kundzewicz

Management of the wood and additives wastes in the wood processing industries: Problematics and technical answers review
1996 - IRG/WP 96-50073
Management pathways for pure wood subproducts are well known and used; but as soon as additives like preservatives, glues, varnishes or coatings are present within the wood wastes, their disposal or valorization becomes more tricky. The different kinds of mixed wood wastes of the wood processing industries, from the sawmill to the furniture manufacture, are identified herewith and their diversity is examined. These wastes can be classified according to their danger characteristics, taking into account the type of additives, their concentration, their availability for the environment, the physical state of the waste. Different disposal pathways are then considered. Combustion, with the possibility of energetic valorization seems the best answer for a major part of these wastes. But this is only possible if good combustion conditions are defined, so that no harmful products are emitted. Moreover, these conditions must be affordable on the technical and economical point of view. Then, some wastes cannot be burned in such a simple way, and need a larger approach, which is presented in this document.
S Mouras, G Labat, G Deroubaix

Proposed method for out-of-ground contact trials of exterior joinery protection systems
1981 - IRG/WP 2157
Methods for testing the efficacy of preservative treatments for exterior joinery are described using the format of a European Standard. Commercially used treatments applied to jointed test units (L-joints) which are then protected by conventional finishes are exposed to normal outdoor hazards out of ground contact. Assessment is made a) by determining eventual failure through decay and b) by destructive examination of replicate treated and untreated units, after increasing time intervals, rating comparative performance in terms of wood permeability increase and the progress of microbial colonisation.
J K Carey, D F Purslow, J G Savory

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

A suggested method to test the toxicity of wood preservatives towards the house longhorn beetle
1977 - IRG/WP 275
This method was developed in the Institute for Wood Technology in Sarajevo, Yugoslavia and is used to get quick information on the toxicity of wood preservatives against house longhorn beetle (Hylotrupes bajulus). The method can be used for superficially treated or deeply impregnated wood blocks, and by using small or normal size test material it can be used as a laboratory or field test, and also for accelerated infestation of test material out of ground contact. The paper is given to the International Research Group on Wood Preservation as a suggested method which could possibly be used as a standard. Only the laboratory test method is described.
N Vidovic

Environmental status of wood preservation in the UK
1994 - IRG/WP 94-50018
The environmental status of wood preservatives and treated wood in the UK is summarised. The current legislatory position with respect to approvals, supply, use and waste disposal is considered. The bibliography at the end of this paper contains details of all publications referred to together with other relevant information although this cannot be exhaustive.
M Connell

Registration and approval of wood preservatives in Australia and New Zealand
2001 - IRG/WP 01-50166-06
Wood preservatives are treated as agricultural chemicals in Australia and, at the time of writing, as pesticides in New Zealand. Antisapstain products are currently considered to be agricultural chemicals in New Zealand while wood preservatives in the future will be considered as hazardous substances under the Hazardous Substances and New Organisms Act when this Act is fully implemented. They are regulated and approved for use by Government Departments under Ministers with responsibilities for agriculture and forestry and the environment: in Australia this is the Department of Agriculture Fisheries and Forestry; in New Zealand it is the Ministry of Agriculture and Forestry and, in the future, the Ministry for the Environment. Specific authorities within these Government instrumentalities control the registration and approvals procedures - the National Registration Authority (NRA) in Australia and, currently, the Pesticides Board in New Zealand. The latter situation is in a transition phase, with the Environment Risk Management Authority (ERMA) New Zealand expected to take over from the Pesticides Board by mid-2001. The NRA and the Pesticides Board require data packages that must include details of the preservative's application, chemistry, manufacture, toxicology, environmental credentials, and efficacy. The NRA administers the Agricultural and Veterinary Chemicals Code, which provides the Authority with the power to evaluate, register for use, and regulate the point of sale of a preservative. The evaluation procedure may involve Environment Australia in focusing on exposure and environmental toxicity data, the Department of Health and Aged Care in assessing toxicity to humans and the National Occupational Health and Safety Commission considering user safety aspects. Efficacy data can be obtained through testing to the Australasian Wood Preservation Committee (AWPC) Protocols. AWPC members may also act as experts in the assessment process and may also be involved in the development of national Standards. Thus, there is a ready conduit from registration and approval of a potential preservative to its incorporation for end use into day-to-day working standards.
H Greaves

Testing of wood preservatives against marine borers (Part 1). Method of testing wood preservatives against marine borers (Part 2)
1971 - IRG/WP 37
P C Trussell, C C Walden

Influence of different fixation and ageing procedures on the leaching behaviour of copper from selected wood preservatives in laboratory trials
2003 - IRG/WP 03-20264
The paper focuses on the role of different parameters, such as fixation, sample size, wood species, and leaching in internationally standardized ageing procedures for wood preservatives from Europe, Japan and the United States. The leaching protocols used were EN 84, JIS K 1571 and AWPA E11 protocols. The wood species were Scots pine, Sugi and Southern Yellow Pine respectively. Three types of commercially important copper-based wood preservatives were used as model formulations, namely copper/copper-HDO, ammoniacal copper/quat and CCA. The most important factors determining the extent of copper leaching in the different lab trials were the sample size (volume/surface ratio) and the fixation conditions prior to leaching. On the other hand, the wood species and the leaching protocol itself were found to have only minor influence on the copper leaching rate in the test methods included in this study.
J Habicht, D Häntzschel, J Wittenzellner

Loss of preservatives from treated wood during service
1992 - IRG/WP 92-3734
During the 23rd IRG conference in Harrogate the matter of preservative losses from treated wood during service was raised. We were asked to collect information in this field and ask now for help from you. Many tests have been carried out at a laboratory scale to study fixation and leaching from wood treated with different preservatives. Very little, however, is reported on losses of preservatives during service. Since these values are of great relevance regarding environmental impact and the final disposal, reuse or recycling of treated wood, it is of great importance to get as much information as possible on the amount of active ingredients lost during service life. We are convinced there are quite a lot of analytical data and additional information available in many places all over the world. It appears to be rewarding to collect those data and put them together adequately to get an astimate of the losses of the different components based on a broad scale of in service situations. This work will be done as soon as information is available and it is intended to present the results on next IRG meeting.
M-L Edlund, D Rudolph

International collaborative laboratory comparison of two wood preservatives against subterranean termites: Third update and first report
1996 - IRG/WP 96-10174
At the 24th annual meeting of IRG in Orlando, USA, in May 1993 an international subterranean termite laboratory bioassay to compare the various preferred termite protocols used by IRG termitologists was initiated. The author was nominated to co-ordinate this comparative laboratory evaluation of two wood preservatives, copper-chrome-arsenic (CCA) and copper naphthenate (Cu-Na) against the subterranean termites used as test termites in Australia, France, Japan, Thailand, United Kingdom and the Unites States of America. Solutions of these two wood preservatives were prepared and impregnated into Pinus radiata wood blocks to obtain loading of 0.0, 0.5, 1.0, 2.0 and 4.0 kg/m³ respectively. All preservative treatments were carried out at the Division of Forestry and Forest Products in Melbourne. The treated specimens were dispatched to the participating researchers who subjected these specimens to attack by their test termite species, and have now returned the specimens to Melbourne. This paper reports the amount of wood consumed and the mean mass loss (%) on both treated and untreated wood blocks by the termites in the various laboratory bioassays.
J R J French

A practical method to evaluate the dimensional stability of wood and wood products
1990 - IRG/WP 2342
This paper presents a new simple method to evaluate wood and wood products for their resistance to swelling and to assess wood preservatives for their ability to dimensionally stabilize treated wood exposed to water. Permeable wood of various dimensions and treated with different preserving chemicals have been measured for swelling in the radial and tangential direction during immersion in liquid water. The results indicate that a simple exponential function describing the dimension of the samples during immersion can be used to evaluate both the water-repellency and anti-swelling effectiveness of wood preserving chemicals. The results can be achieved in reasonable time, and the parameters of the function can be determined by a commercial desk-top computer program.
J P Hösli

Report on the activities of the European Standardization Committee CEN/TC 38 'Methods of Testing wood preservatives'
1980 - IRG/WP 279 E
G Castan

Laboratory decay test of Burmese in and kanyin treated with three wood preservatives
1982 - IRG/WP 3210
Laboratory decay tests were performed on samples of In (Dipterocarpus tuberculatus Roxb.) and Kanyin (Dipterocarpus alatus Roxb. and Dipterocarpus turbinatus Gaertn f.) pressure treated with three wood preservatives - copper arsenic additive (CAA - a variation of ammoniacal copper arsenate), Arquad C-33 (a waterborne quaternary ammonium formulation), and tributyltin acetate (TBTA) dissolved in ethanol. Pressure treatments with each preservative involved a 0.5 - 1 hour vacuum followed by a 4 hour period of pressure. This resulted in a very variable treatment because of the inherent difficulty in treating these woods. The decay tests entailed a slightly modified form of the AWPA M10-77 standard soil-block test using three brown-rot and three white-rot fungi. The untreated In and Kanyin samples were moderately susceptible to decay though weight losses were very variable and some samples of Kanyin (usually the densest and least permeable) were naturally resistant. At the concentrations tested CAA was the most effective in reducing weight losses incurred in the soil-block tests. TBTA was successful in controlling decay caused by all but two of the test fungi. It is suggested that preservative retentions for TBTA conforming to those included in the Candadian standard for bis (tributyltin) oxide would exceed the toxic limit for all the fungi tested
J N R Ruddick, R S Smith, A Byrne

Problems of fixation of CCA-preservatives in palm-wood
1985 - IRG/WP 3338
Palm-wood may be used for posts and poles where it needs proper treatment for long time use. Based on observations by W. Killmann on low CCA-fixation in palm-wood, samples of Jubaea-palm grown in a Greenhouse at Hamburg, have been treated in two different series with a 4% solution of CCA-type B. After 1-16 weeks of storage the blocks were split into sticks of 1-2 mm² and leached. In all series 50% of the chromium and copper content of the individual blocks was leached independent of the time of storage, whereas simultaneously treated pinewood samples showed complete fixation after 4 weeks of storage.
H Willeitner, K Brandt

Protocol for evaluation and approving new wood preservative
1985 - IRG/WP 2159
M E Hedley, J A Butcher

A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been elucidated although two oxalate-forming enzymes, oxaloacetase and glyoxylate dehydrogenase, have been studied in our laboratory. Recently, a new role of glyoxylate cycle in oxalate biosynthesis in wood- rotting fungi has been presented, and the cycle commonly occurred to varying extents among the fungi although they were grown on glucose. Enzymatic analyses showed that isocitrate was cleaved by isocitrate lyase in the glyoxylate cycle rather than oxidized by isocitrate dehydrogenase in tricarboxylic acid (TCA) cycle, and the fungi were found to lack a normal TCA cycle due to the absence of - ketoglutarate dehydrogenase. It is noteworthy that glucose was efficiently converted to oxalate in a theoretical yield of about 80%, accumulating in the culture media of F. palustris. The results further indicate that acetyl-CoA derived from glucose was not completely oxidized to CO2 in TCA cycle but was mainly converted to oxalate with help of the other coupling metabolic cycles, including glyoxylate cycle. Formation of oxalate from several intermediary metabolites using cell-free extracts of F. palustris confirmed that oxalate is also the final product of the metabolic pathway in the in vitro system. Thus, it is proposed as a new concept that most of copper-tolerant brown-rot fungi may acquire the energy by oxidizing glucose to oxalate, i.e. oxalate fermentation expressed in the following equation; Glucose + 5O2 --> 2 Oxalate + 2CO2 + 4H2O.
E Munir, T Hattori, M Shimada

Comparison of the agar-block and soil-block methods used for evaluation of fungitoxic value of QAC and CCA wood preservatives
1994 - IRG/WP 94-20039
The modyfied agar-block and soil-block methods were used for comparing the fungitoxic value of QAC and CCA type preservatives against Coniophora puteana and Coniophora olivacea The mass loss and moisture contents of wood were analysed.
J Wazny, L J Cookson

The proposal for the method of testing the phytotoxic effect of wood preservatives
2000 - IRG/WP 00-50163
Four methods of testing the phytotoxic effect of wood preservatives are proposed as the unified test by: - direct application of the preservatives to the test plants by spraying; - direct application of the preservative to the soil substrate; - indication plants growing in the vicinity of treated wood; - seed germination rate on the treated substrate.
J Wazny, P Witomski

Copper naphthenate performance: A new way to look at old data
2000 - IRG/WP 00-30215
Although copper naphthenate has over a 50-year test history, it is still considered as a "new" preservative in the United States when it is used for utility poles. It has also been extensively used in remedial treatments for poles and has considerable retail or over-the-counter sales. The test history includes a number of different tests and a rationale for evaluating this data and comparing the performance of copper naphthenate to other common pole preservatives is presented. Thus, the efficacy of copper naphthenate can be easily summarized.
C R McIntyre

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