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Ammoniacal wood preservatives for use in non-pressure treatment of spruce and aspen poplar. Part 2
1984 - IRG/WP 3274
A series of thermal diffusion treatments were carried out on unseasoned white spruce (Picea glauca (Moench) Voss) lumber and air dry aspen poplar (Populus tremuloides Michx.) timbers using an ammoniacal copper arsenate wood preservative. Under the specific conditions described, certain charges of lumber met the present Canadian Standards Association Wood Preservation Committee's requirements for wood in ground contact, having 10 mm penetration and 6.4 kg/m³ loading. The average preservative penetration in the heartwood of white spruce lumber ranged from 6.3 mm for charges of nonincised lumber to 13.9 mm for incised lumber. Preservative retention in the treated area was above 6.4 kg/m³ in four of the five charges of spruce lumber treated by this method. Aspen poplar timbers treated by thermal diffusion averaged 16.4 kg/m³ oxide retention. Post-treatment procedures such as close piling the lumber resulted in material with cleaner surfaces and more even penetration of preservative components.
C D Ralph, J K Shields


Radical changes in the requirements for more safe pressure impregnation in the Nordic countries in 1988
1990 - IRG/WP 3581
After introduction of quality control schemes and standards in the Nordic countries during the seventies, the first radical change of the standards and practice of work took place after pressure from the labor unions and authorities in 1988 and 1989 in Denmark and in Sweden. A new class of preservation with less retention for out of ground contact use was introduced, fixation times were prolonged to 6 and 14 days, and branding became a requirement. At the same time, treating companies replaced CCA with arsenic-free preservatives, and started using processes for accelerated fixation. Drying of treated wood was started to be used widely.
B Moldrup


Developing the technical guidance document on data requirements for biocidal products
1998 - IRG/WP 98-50101-02
Finland has been developing a discussion document for EC and the Member States concerning the specified data requirements for 23 biocidal product types, including wood preservatives, and their active substances. This data is required when applying for authorisation for a wood preservative according to the forthcoming Biocides Directive. The data requirements comprise of the core data set, which is common for all product types, and the product type specific additional data sets. The core data set has been outlined in the common position of Biocide Directive adopted by the EU Council and has only been complemented with some technical details. The data required in the additional data set is supplementary to the core data set and it takes into consideration the product type specific properties and direct and indirect human and environmental exposure. At the same time other guides have also been preparing: a guide for risk assessment of active substances by Sweden and a guide for risk assessment of biocidal products by UK. Close cooperation with these projects is an essential part of the preparatory work. After finalizing the draft discussion papers by the end of February 1998 the formal discussion on these will take place with EC and the Member States during 1998. The proposals on the data requirements will be circulated for comments to the EC, the Member States, industry and other interested parties. The final document will be addressed to the authorities and the applicants.
P Karvinen, E Nikunen


Rates of emission from CCA-treated wood in the marine environment: measurement, modelling and requirements for further research
2001 - IRG/WP 01-50166-12
Accurate estimates of rates of emission of leachate from preservative treated wood are crucial for realistic predictions of the environmental impact of its use in maritime construction. Estimates are available for some commonly used preservatives, but these vary widely. Though variable, these measurements suggest that emission generally decreases exponentially with time. Part of the variation is due to differences in methodology employed. Physical and chemical characteristics of the seawater used (e.g. temperature, salinity, pH and oxygen content) affect emission rate. So too do the specifics of the treatment process especially the preservative formulation used, and pre- and post-treatment handling of the wood. The nature of the treated wood samples is also important, with misleadingly high estimates being obtained from samples with unrepresentatively high proportions of cross-cut surfaces. A suggested strategy for developing an informative and standardised methodology is discussed. To form useful models of impacts of leaching, emission rates need to be considered in conjunction with site-specific information regarding a) water exchange rates between the area where leaching occurs and the sea, and b) the extent of partitioning of leachate between the water column, biota and sediment. The risk of environmental impact may be reduced by modification to treatment procedures and by careful planning of installation.
S M Cragg, C J Brown, R A Albuquerque, R A Eaton


European standardization for wood preservation
1989 - IRG/WP 2335
G Castan


Requirements for hosting the Secretariat of IRG
1995 - IRG/WP 95-60057
IRG Secretariat


Monographic information on Paxillus panuoides (Fr. ex Fr.) Fr. (First draft)
1978 - IRG/WP 184
A Käärik


Evaluation and approval of wood preservatives. Unification of European requirements
1988 - IRG/WP 2310
This paper reviews the current activities within the European Homologation Committee for Wood Preservatives (EHC) towards unification of the requirements on evaluation and approval of wood preservatives in Western European countries.
J Jermer


The Biocidal Products Directive ( 98/8/EC ) - its consequences for the wood preservation industry
2001 - IRG/WP 01-50166-04
1. The Current Position This European Union Directive is one of the most technically complex pieces of legislation that has been developed by the European Commission (EC). Although the Directive was to have been implemented in the legislation of individual Member States of the EU by May 2000 progress has been slow. A number of Member States have yet to declare the Competent Authority who will handle their legislation. The body text of the Directive cannot stand-alone and is dependent on ancillary regulations and the development of technical guidance for both the Competent Authorities in the Member States and also industry to understand their roles in the whole process for the regulation of biocides and the biocidal products containing them. The process is far from complete in terms of a piece of workable legislation and this leaves not only industry but also the Competent Authorities with significant areas of uncertainty. This is potentially economically and socially damaging to the marketing and use of biocides and biocidal products. Because of this evolutionary process this paper can only be written in general terms as by the time the symposium takes place some significant changes to the position at the time of writing may have occurred. 2. Background The Biocidal Products Directive (98/8/EC), (BPD), is a directive which requires that biocides ( as active substances) are approved for use within the EU and the individual biocidal products containing these active substances are approved for use by the Competent Authority(s) of the Member State(s) in which it is intended to market the product. The product authorisation obtained in the first Member State should be mutually recognised by the other Member States in which application for authorisation to place the product on the market is sought. The Directive has to be seen in the context various other Directives, notably the Plant Protection Directive 91/414/EC). Biocidal products are grouped in the directive into twenty three "product types" and wood preservatives are Product Type 8. The intention of the directive is to harmonise the requirements for the placing of biocidal products and active ingredients on the market throughout the EU. EU wide use of so-called Common Principles are intended to be used to assess the dossiers in order to achieve a common approach and eliminate the current situation where individual Member States apply their own particular national approaches and criteria in the assessment and regulation of products . Annex IIA of the directive identifies the data requirements for the active substance and Annex II B for the biocidal product. There are additional data requirements identified in Annexes IIIA and IIIB for each product type reflecting potential for exposure to man and the environment. 3. Entry onto Annex I Any new active substance will require approval before it or any biocidal products including it can be placed on the market. The dossier to be submitted to the EC will have to include additional data and risk assessments for the product types (as defined in the BPD) in which it will be intended to be used. For those active substances that are accepted as being existing substances on the market before May 2000 (say in wood preservatives) these will be ranked and prioritised. This process is being defined in the so-called: Review Regulations. 4. An environmental directive There is no doubt that this Directive has a high environmental content in terms of the data and the associated risk assessments which are to be prepared. The protocols and the end points for some of these data requirements are still being developed. In general the EC considers that modelling exposure using human and environmental exposure scenarios covering the end use of the product is an acceptable approach . Data are required to enable these scenarios to be modelled and risk assessments made. It is necessary that regulators do not make decisions based on hazard assessment alone in the absence of fully worked out and agreed emission scenarios to define exposure levels which generate a realistic worst case risk assessment. Risk is a function of both hazard and exposure. A lot of work has been done in the development of Technical Notes for Guidance intended to help the regulator and the applicant in the submission and the interpretation of the data. Whilst it may be the case that the human toxicity data requirements still leave questions to be answered it is in the environmental aspects part of the regulatory process where there is still much work to be done. The Directive would seem to rely heavily on the development of Pass / Fail criteria in simulation tests. This is a big subject and of key importance to the risk assessment. 5. Wood preservatives ---- a test case Wood preservation has achieved a certain reputation. On the one hand it is said that a prime reason for the development of the Biocidal Products Directive arose from European problems in the regulation of the marketing and use of dangerous substances, notably wood preservatives. On the other hand because wood preservatives have been regulated by a number of Member States for many years it is believed they are well understood. The EC and the Member States also wanted to be seen to have achieved early success in the implementation of the Directive therefore the decision was taken to start, following failings with the speed of progress of the Plant Protection Products Directive, with a product type they knew all about i.e. wood preservatives. There is no doubt that there is a much greater understanding on the exposure scenarios, both human and environmental, for wood preservatives than many other product types. However, would it not have been better to have tackled some of the other product types where such an understanding is much less well developed? It is regrettable that the EC and Member States did not feel able to accept the results of an EC sponsored study (Haskoning report) on the assessment of risks for all the product types covered under the BPD. The results of this study clearly showed that wood preservatives did not constitute the most significant risk to man or the environment and in fact the risk was significantly greater for other product types. 6. Wood preservatives and the OECD Biocides Programme Another speaker will be covering this subject in more detail. Suffice it to say that because of the perception there was good knowledge about wood preservatives again they were selected as the pilot for an OECD project looking at environmental and human exposure assessment under the OECD Biocides Programme. The findings from two OECD Workshops actually demonstrated there was still much to be learnt about wood preservatives in order to refine the risk assessments to a state where they would be sufficient for the requirements of the BPD. This work is ongoing but it clearly demonstrates the problems that both the regulator and industry will have in the preparation and the assessment of the dossiers for both the active substances and the biocidal products. This is especially the case for other biocidal products that have not been subject to the same kind of regulation that wood preservatives have subjected to in the past. 7. Inorganic and organic biocides With current wood preservation technology there is still a dependence on inorganic chemicals such as copper (in conjunction with other biocides) or with chromium, as well as arsenic and boron for many end use applications. This is very much the case where a long term service life is a key factor in the use of treated wood for that end use. These substances are commodity chemicals and are also covered under the Existing Substances Regulations (EC) 1488/94. There is also work going on revising the Technical Notes for Guidance covering them . This includes a significant addition in the environmental risk assessment area. Efforts are being made to integrate and coordinate the requirements for both the BPD and the Existing Substances Regulations and OSPAR ( OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic). OSPAR refers to the Oslo Paris Convention. Whilst the BPD seems primarily aimed at the regulation of biocides based on organic chemicals wood preservative products may contain both inorganic and organic components. Indeed there are probably few wood preservative formulations on the market that contain only one active substance. This must have a significant impact on the way the dossiers are prepared for the active substance and the biocidal products and how they are assessed both at the EC and the Member State level. 8. Consequences of the BPD for the wood preservation industry Whilst this paper addresses the consequences for the wood preservation industry per se, it must not be overlooked that there may be implications for the fabricaÈors of articles made from treated timber. Some current wood preservative formulations may over a period of time be withdrawn from the market because the risks and costs of generating the data and the preparation of the dossier make the product economically unviable. The presence of large working volumes of wood preservative solutions at treatment plants requires realistic withdrawal periods to avoid the unnecessary disposal and associated environmental risk of products that have been used satisfactorily for many years. 9. Availability of active substances The structure of the industry has changed dramatically in the past few months and there is no doubt that other changes both within and outside the wood preservation industry itself are yet to happen. The original differentiation between formulator of wood preservatives and active substance suppliers to the wood preservation industry has become blurred. Some of the active substances used in wood preservation are used in other either other biocidal product types or in products regulated under another directive, e.g. Plant Protection Products Directive 91/414/EC. 10. Data protection This continues to be a key issue for industry and some companies may find it strategically or financially necessary not to support an active substance in a particular product type thus leaving that sector without being able to use the active substance. The coming months will start to reveal which active substances are likely to be supported, at least through the notification process. Formulators are therefore in a close dialogue with their suppliers to try to determine their intentions on whether or not they intend to support their active substance. Today's wood preservative formulations are largely multi active substance based. Product costs, efficacy spectra, niche marketing and other considerations have made this process inevitable. New wood preservative formulations take time to research and develop and the continuity of availability of a choice of active substances is of key importance. A lack of adequate return on investment necessary to sustain the development of new products could have a negative impact on innovation and the rate of introduction of new products. It is extremely unlikely that any new active substance will be solely developed for use in wood preservation. This would be an effect contrary to expectations of the EC. The situation with wood preservatives is complicated by the fact that treated wood is a construction product and comes under the scope of the Construction Products Directive (89/106/EEC) (CPD). Products under the scope of the CPD are required to meet certain so-called essential requirements and one of these is durability. Demonstration of compliance involves the extensive suite of CEN wood preservative efficacy tests. Even relatively small changes in formulations may require extensive re-testing under the EN 599 regime in some Member States. 11. Task Forces Companies are encouraged by the EC to enter into Task Forces in order to reduce the burden of testing on animals and also to reduce the number of dossiers to be reviewed for each active substance. Ideally, and understandably, the EC would like one dossier per active substance. Parts of the wood preservation industry have been co-operating in Task Forces and much practical experience has been gained. Even closer co-operation will be required and this will enable companies to pool experience and expertise and manage their financial exposure to potentially high regulatory costs by sharing them amongst a larger number of parties. 12. Financial aspects Industry will have to make some best guesses with respect to its investment programmes for supporting its portfolio of products. Formulators and active substance suppliers are likely to group into Task Forces in order to reduce their costs in terms of data generation and the fees likely to be charged at the EU and the Member State level for the assessment of the dossiers. The compilation of the dossiers requires specialist expertise to assist the industrial applicant(s). This is likely to cost in the order of £100,000 per active substance, not including the costs of generating any data. The Rapporteur State's costs for reviewing the dossier is also expected to be of the same order. Clearly these kinds of costs will impact on innovation. An adequate payback must be available to the company to justify this level of investment. 13. Will mutual recognition work? Member States are required to recognise the authorisation of the biocidal product placed on the market in the first Member State when subsequent applications are made to place the product on the market. This is a fundamental principle of the BPD, although there is concern that Member States continue to have enough flexibility to prevent this happening if there are particular concerns in that Member State. Industry very much hopes this will not be the case and that mutual recognition, a fundamental principle of the BPD, will work in practice. 14. Environmental aspects Biocidal products such as wood preservatives are generally applied in controlled situations and not over large areas. Consequently any emissions can be considered to be from discreet sources, such as treated timber or potentially from timber treatment plants. This is in contrast to plant protection products and some other biocidal products that are usually dispersed over a relatively large area. Because of this a lot of work is required to be done to re evaluate how the environmental aspects of biocidal products such as wood preservatives can be assessed in an objective manner. The criteria that define an emission and how the PEC (Predicted Environmental Concentration) for each environmental compartment is determined are critical. The wood preservation industry, through the EWPM (European Wood Preservative Manufacturers Group), has been working with institutes and other interested parties in a co-operation known as the EFG (Environment Focus Group) to progress the development of appropriate methodology. Data will be required for both primary and secondary exposure to treated timber. The protocols for this work are yet to be agreed. This work is being further progressed in the OECD together with input from CEN TC 38 WG27. This co-operation between the OECD and CEN is extremely significant in that it is, I believe, the first time such a co-operation has taken place in the development of an OECD Guideline. If one considers all of the end uses where treated timber may be found carrying out a risk assessment with few guidelines on how it should be done is a very uncertain process for both industry and the regulator. Reliance on so-called expert opinion may be inadequate. 15. Comparative assessment (the substitution principle) This is a process whereby the health safety and environmental properties of acti_u101 ? substances used in the same product type could be compared and those with the most undesirable properties would not be placed on Annex I. Consequently biocidal products containing them would have to be removed from the market. This process is embodied in the BPD but it was initially considered that it would only be applied in the event of problems arising with active substances or products containing them rather than being used as a screening tool early on in the review process for active substances. This area is still an uncertain one with Member States having different interpretations of this principle. It is unfortunate that the wood preservation industry could be used to test out this concept at a European level. The consequences of this principle could be further losses of active substances available to the wood preservative formulators. 16. Substances of concern The BPD is not only concerned with the active substances that are formulated into the biocidal product but also with so-called "substances of concern". These are defined as any substance, other than the active substance, which has the inherent capacity to cause an adverse effect on humans, animals or the environment and is present or is produced in a biocidal product in sufficient concentration to create such an effect. There are significant implications for the formulator of the biocidal product . The formulator may have to submit an extensive dossier containing toxicological and metabolic as well as ecological data on each of the substances of concern when seeking approval for the biocidal product. There may be classes of compounds that become unavailable to the formulator either because of the risks posed by the co-formulant or because the cost of generating data will be uneconomic. 17. The wood preservation Industry's view on the BPD Industry has supported the development of the BPD since its conception in 1989. It is still supportive it but believes that the degree of complexity is disproportionate to the level of risk when it comes to wood preservatives. After all wood preservatives have been regulated for a long time and in reality there have been few significant health safety and environmental problems associated with them. Industry believes there is no need to determine an absolute understanding about a biocide and its application but rather there is a need to determine the level of understanding that will enable characterisation so that a risk assessment can be made. The wood preservation industry has sought either directly or through representative bodies a pro-active and collaborative approach with the regulators although at times this appears to have encouraged inappropriate demands. The regulators have invariably responded positively to this however they may not always understand the burden in both time and resource in having made wood preservatives the test case. Industry hopes that its efforts to be pro-active will be recognised and will be dealt with equitably when considered before the other product types defined in the Biocidal Products Directive.
D Aston


Requirements for hosting the Secretariat of IRG
2006 - IRG/WP 06-60227
IRG Secreteriat


How to determine what is a realistic emission from treated wood - basic reflections
1998 - IRG/WP 98-50105
Emissions from treated wood occur by evaporation and by leaching. Up to date by far more experience exists on leaching tests than on evaporation test. The methods applied will be of interest to give answers to the questions about the quantity of possible emissions. Standardisation on leaching started very early. One of the first attempts to quantify the effect of leaching on the remaining efficacy was the German DIN 52176-2 (1941) which was the basis for EN 84 first published by CEN in 1978. A specific German standard for the determination of leachates was published in 1972 (DIN 52172-2), however, the viewpoint was still the efficacy of wood preservatives. With respect to pollution of the environment EN 1250-2 (1995) has to be mentioned, however, this is more or less only a modification of EN 84 and as such not very satisfactory. Evaporation tests started as late as in the 50th mainly in connection with fluorides and later with PCP. Examples for a standard to determine the remaining efficacy are the German Pre-Standard DIN 52172-3 (1971) and EN 73, based on the German standard and first published in 1978. A specific standard for emissions is EN 1250-1 (1995). The reflections presented in the paper consider evaporation as well as leaching tests where the general requirements and the statements to the kind of specimens and to the treatment apply to both types of emissions at the same time. For the test procedure itself, however, different methods are needed.
H Willeitner, R-D Peek


Risk assessment and the approval of wood preservatives in the United Kingdom
1995 - IRG/WP 95-50040-23
An approval system operates in the United Kingdom (UK) for the regulation of wood preservatives. The regulatory authority uses a risk assessment approach to evaluate how far the potential for harm to people and the environment from wood preservatives is likely to be realised in practise, and hence the controls required for products to be, used safely. The evaluation for approval purposes also takes into account the effectiveness of wood preservatives. A tiered approach is adopted to data requirements, and likely exposures are considered under the proposed conditions of use so that testing is minimised and controls are commensurate with risk.
R M Turner


Exterior wood stains
1980 - IRG/WP 3135
Experience has shown that conventional paints cannot now be relied upon to provide a complete seal against water entry, that in practice water can often circumvent the film and that the paint, far from serving to keep water out will seal it in. Moreover present-day paints are often subject to localised and premature failure out of doors and consequently entail high maintenance costs. Problems of wood decay and premature paint failure reached a high level during the 1960s, and led to the acceptance of the need for the preservative treatment of softwood joinery and cladding. The question remains however, whether, in the light of changes in the quality of timber and how it is used, the traditional approach of attempting to seal the outer surface of the wood is still valid, or should be abandoned in favour of using different types of finish which are more permeable to moisture and prevent it accumulating in the timber. One of the reasons for the remarkable success of semi-transparent exterior wood stains is that they met the demand for finishes of increased water vapour permeability for timber which was susceptible to decay. They also possessed two other important attractions: they provided natural finishes for exterior timber which were without the technical problems of clear varnish; and their mode of breakdown by erosion reduced the preparation work in maintenance and hence the overall maintenance costs. These are valid commendations for stains and remain important factors encouraging their use. Stains offer the architect additional design freedom and, used effectively, can make a pleasing contribution to the appearance of modern buildings. They do reduce average moisture levels in the timber and are simple to maintain, though these advantages may be offset to some extent if more frequent maintenance is necessary and if the higher permeability creates problems from dimensional movement.
E R Miller


Preservative requirements for exterior particleboard as predicted from accelerated laboratory evaluations
1976 - IRG/WP 265
Arguments for and against preservative treatment of exterior particleboard were considered; it was concluded that preservative treatment is desirable. Laboratory decay tests were conducted to determine levels of sodium pentachlorophenoxide required to protect exterior particleboard from decay fungi. The decay resistance of treated board was compared with that of timber (both naturally durable and preservative-treated) currently used in situations for which exterior particleboard is designed. A retention of 0.35% sodium pentachlorophenoxide per oven-dry board weight was considered to offer adequate protection to the board.
M E Hedley


Test Methods – Performance Based Requirements
2004 - IRG/WP 04-20297
In this paper is briefly described the present approach to service life prediction as an essential part of the architectural engineering process. The system of testing the durability of wood is described more in detail including laboratory tests as well as field trials. It is concluded that the system has a lot of weaknesses which makes it less well suited for practical building applications. A leading theme in the criticism is that the test and classification systems are based on the requirements of the wood and preservation industry rather than those of the end-user. Finally a proposal is given for a working group to deal with this issue.
M-L Edlund, F Englund, J Jermer, T Nilsson, M Westin, K Ödeen


Ammoniacal wood preservative for use in non-pressure treatment of spruce and aspen poplar. Part 1
1984 - IRG/WP 3273
End-matched lumber of Picea glauca (Moench)Voss (white spruce) and Populus tremuloides Michx. (aspen poplar) timbers was treated by a thermal diffusion process in open tank treating vessels using an ammoniacal copper-arsenate wood preservative. The process proved technically feasible with respect to controlling the vapourization of ammonia from open tanks during treatment at high temperatures. Treatments of 48 hours or more on unseasoned and partially dried lumber produced net oxide retentions above that required by the Canadian Standard Association CSA-080 wood preservation standard for timber in above ground contact situations. Although preservative penetrations did not meet the penetration requirements (10 mm), of the CSA 080.2 standard for ground contact, five of the seven non-pressure charges on spruce lumber had heartwood penetrations greater than 7 mm in depth. A 24-hour treatment on air-dried spruce had penetrations equivalent to a five-hour vacuum-pressure treatment. Retention was adequate for above-ground exposure
C D Ralph, J K Shields


Data requirements for wood preservatives in the EU Biocides Directive
2001 - IRG/WP 01-50166-08
Directive 98/8/EC of the European Parliament and of the Council concerning the placing of biocidal products (the Biocidal Products Directive, BPD) lays down the requirements on data needed for authorisation of a biocidal product and approval of its active substance(s). The dossier must contain data needed for the proper risk assessment of the biocidal product. A detailed technical guidance document on data requirements for biocides has been produced to ensure the harmonised decision making according to the BPD. The purpose of the guidance is to give detailed testing strategies e.g. for toxicology, ecotoxicology and efficacy of different biocidal products and active substances, including wood preservatives. The data requirements for biocides are divided in two parts: the common core data set lists the studies which are always required, and the additional data set lists the studies which may be required in certain cases e.g. on basis of the results of the tests in the common core data set, and proposed uses and the potential exposure for a biocidal product. The common core data set contains a very comprehensive list of toxicological studies and, therefore, their additional data set is very limited. Instead, for ecotoxicological studies the common core data set is very limited, but the additional data set is very broad. Therefore, the guidance document on data requirement lists those additional ecotoxicological studies that are usually always required for certain biocidal product types - also for wood preservatives - in the application for approval. Waiving for some toxicological studies may be needed to minimise the need for animal testing and to reduce the costs of testing. The technical guidance document for data requirements gives some guidance on such a possibility on exemptions on the data requirements. The need for additional ecotoxicological testing depends on the product type and potential exposure for a product. In addition, the environmental risk found as a result from common core data set is the basic criterion when deciding testing strategy and the need for the additional ecotoxicological testing on e.g. adsorption, degradation and bioconcentration. Issues important for wood preservatives are data required on efficacy and on leaching from treated wood.
H Braunschweiler


Wood Preservatives Science Issues: US EPA’s Perspective
2005 - IRG/WP 05-50224-2
The USEPA Office of Pesticide Programs (OPP), Antimicrobials Division (AD), regulates the use of chemicals registered as wood preservatives in the United States. An overview of the registration and re-registration process is presented. The wood preservatives data requirements include toxicological, human exposure, ecological, and environmental fate data. A detailed discussion of wood preservatives data requirements is presented. Currently, the three heavy duty wood preservatives (Pentachlorophenol, Chromated Copper Arsenate, and Creosote) are undergoing the re-registration process. This process is mandated by Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The re-registration process ensures that older pesticides meet contemporary safety standards and data requirements. The challenges of regulating the treated wood will be discussed.
N Elkassabany


Moisture requirements and wood degradation of pine and spruce wood by some Basidiomycetes-fungi
1989 - IRG/WP 1406
The minimum moisture requirements for the growth of the brown rot fungi, Coniophora puteana, Gloeophyllum trabeum and Serpula lacrymans were near or above the fibre saturation point of pine and spruce, sap and heartwood, during 160 days incubation according to the standard method EN 113. The moisture of wood for the optimum growth of Coniophora puteana and Serpula lacrymans was about 35-80% and for Gloeophyllum trabeum about 60-250% depending on the state of decay and wood species. The moisture content of wood was increased by the fungi, and there was a positive regression between the weight loss and the moisture content of wood. The effect of Coniophora puteana and Serpula lacrymans on the moisture content of wood was near to assumed values calculated according to the loss of carbohydrates. The effect of Gloeophyllum trabeum on the weight loss and moisture of wood was very fast and strong. The samples of pine heartwood were during 60 days incubation quite durable against the studied fungi, but after 120 days its resistance broke down. The weight losses of other studied wood types were higher.
H Viitanen, A-C Ritschkoff


Some factors affecting the treatability of spruce roundwood with ammoniacal preservative solutions
1976 - IRG/WP 371
Permeable wood species for use in preservative-treated commodities are becoming depleted in Canada. Spruce can be a convenient replacement for them from local resources provided it can be treated to levels adequate for protection of commodities in ground contact. Basically, two approaches were taken to improve treatability of difficult-to-penetrate softwood species; first, to improve the permeability of wood and second, to improve the penetrating properties of liquids. The first approach involves various means of wood pre-treatment: biological (enzymes, moulds and bacteria including ponding), chemical (removal of extractives), mechanical (precompression) and technological (presteaming of green wood, replacement of water in wood by solvents). There are a great many publications devoted to individual topics mentioned here indicating the significance of the subject. The second approach is the selection of a solvent capable of penetrating into the wood better than conventional solvents for, preservative compounds.
J Rak


Fungi causing sap stain in wood
1980 - IRG/WP 199
The present paper is a revised edition of former Document No: IRG/WP/125. It contains some additions and an explanation of terminology, as was suggested at a previous meeting of the Group. The paper is a compilation based mainly on available literature. Some of my own unpublished results have been added together with other unpublished data which have been received from the Bundesanstalt für Materialprüfung in Berlin and from colleagues at the Department of Forest Products, Swedish University of Agricultural Sciences, which are acknowledged with thanks. Fungi, described in the text, have been selected according to the following principles: a) the most common and important blue stain fungi, b) less common fungi which have been found in several countries or on several host trees, c) fungi which seem to be of minor interest as blue stain fungi, but which have been used recently in experimental work considering their physiological characters, susceptibility for toxic substances etc. The author regrets that this paper does not cover the tropical fungi, as there have been only a few notes about these in reviews and as the original papers have not been available to our library.
A Käärik


Blue stain in service on wood surface coatings. Part 1: The nutritional requirements of Aureobasidium pullulans
1992 - IRG/WP 92-1556
The nutritional requirements of Aureobasidium pullulans was examined with regard to nutrient sources that are potentially available in fresh and weathered wood. The study was designed to determine how far wood cell wall components need to be broken down during weathering before they provide a useful nutrient source for Aureobasidium pullulans. Various carbon sources were tested, with eight different isolates of Aureobasidium pullulans. It was found that the organism could utilise the simple sugars well, but not the oligosaccharides. The organism was also able to utilise well several lignin precursor compounds.
P R Sharpe, D J Dickinson


Commercial antisapstain chemicals in New Zealand
1980 - IRG/WP 3142
Almost all sawn timber of exotic softwoods (principally Pinus radiata) and a large proportion of indigenous sawn timber receives an antisapstain chemical treatment to prevent fungal degrade during subsequent seasoning, storage, or transportation (if exported). Antisapstain chemicals are also widely used to protect freshly peeled round produce during drying. A further, specialised, use is as the fungicidal additive to concentrated boron salt solutions used in boron diffusion treatment of sawn timber; such timber is very prone to mould and stain during the diffusion period. In all cases, the chemical is applied to green timber by momentary immersion in the solution, or by spray. The amount of solution that remains on the surface of dipped timber is very small; solution uptake by dipping green 100 x 50 mm² rough-sawn timber is approximately 18 litres/m³ - equivalent to 1 gal/100 bd ft of 4 x 2 in². The concentration of chemical in solution is that shown by experimentation or experience to be necessary to inhibit almost all fungal growths for a period of 3-4 months. However, adjustment to solution concentrations is often necessary if full cost-effectiveness of the treatment is to be achieved. For example, in winter and early spring chance of fungal infection is usually low, so solution concentrations can be reduced. In contrast, wet warm summers tend to promote fungal degrade and so solution concentrations need to be increased. The condition of the timber also dictates concentrations. Rough-sawn timber absorbs more solution than planer-gauged material, so concentrations must be increased if gauged timber is to obtain adequate protection. This is of particular concern when mills attempt to gauge timber before boron treatment; lack of mould and stain control has limited this worthwhile development. Since antisapstain treatment results only in a superficial deposit of fungicide on the surface of green timber it is merely a preventive, or prophylactic, treatment. The full success of an antisapstain chemical in preventing fungal degrade therefore depends on the timber being free of infection at time of application. Prompt handling between felling, conversion, and antisapstain treatment is a prerequisite of treatment.
J A Butcher


Effect of substrate type and moisture requirements in relation to colony initiation in two carpenter ant species
1999 - IRG/WP 99-10320
Conditions necessary for optimal colony initiation or the rate of initial colony expansion by early brood in the carpenter ant species Camponotus modoc and C. vicinus on various substrates conditioned to different moisture contents were studied. Camponotus modoc and Camponotus vicinus queens were placed in Douglas-fir, western red cedar and Styrofoam® blocks conditioned in sealed chambers at 70% or 100% relative humidity. Chambers were periodically monitored for changes in substrate weight, numbers of eggs, larvae, pupae, and worker ants produced. Brood counts produced after thirteen weeks were used to assess the effects of substrate and moisture content on colony initiation. Queens of C. vicinus in Douglas-fir and Styrofoam® produced worker numbers that did not differ significantly with moisture content. However, the number of colonies initiated for C. modoc did significantly differ with moisture content. The results indicate that colony initiation in C. vicinus is less sensitive to moisture content then C. modoc for Douglas-fir and Styrofoam®. No differences were found between moisture contents for ant queens in western red cedar, due to a lack of colony initiation. These results suggest that cedar was detrimental to the development of early brood in both ant species.
M E Mankowski, J J Morrell


Wood preservation requirements in Queensland, Australia
1983 - IRG/WP 3227
In Queensland the preservative treatment and utilization of timber must comply with the Timber Users' Protection Act. Preservative retention levels and penetration patterns must be complied with. Analytical zones are specified for removing samples for chemical analysis of preservative retention. The required retention levels have been expressed as percent weight of oven dry wood weight. This specification has allowed the same retention figures to be equally effective in preserving timber species of differing densities.
L E Leightley, M J Kennedy


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