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Towards harmonisation of regional approaches for an International Standard for the approval of wood preservatives
1997 - IRG/WP 97-20122
Recent proposals from the European Standards body (CEN) for an ISO Standard on wood preservatives has initiated debate on whether there is any prospect of an acceptable common approach among ISO member countries, to a harmonised framework of hazard classes, with agreed supporting biological tests, leading to a unified rationale for demonstrating compliance with minimum performance standards for specific preservatives in specific end-uses. This paper discusses a potential framework for developing an International Standard prescribing hazard classes and the biological test methods capable of supporting a common approach to the approval or standardisation of a wood preservative system. An approach is proposed which incorporates elements of existing standards or protocols used in Europe, Japan, Australasia, South Africa and North America based on the framework of European Standard EN599 but adopting regional variants with incorporation of field testing for the suggested Hazard Classes 2, 3, 4a, 4b and 5. The proposals are intended to initiate development of a consensus process rather than to suggest a solution in itself. However, it is hoped that the framework provided will allow the discussion process to advance more effectively and harmoniously.
A F Preston, A F Bravery


How to Document the Performance of Super-Critical Treated Wood in above Ground Situations?
2005 - IRG/WP 05-20316
The paper presents practical experiences from the preparation of a new preservative treated wood product for introduction to the market. The product in question is Superwood™, which is treated with organic biocides using CO2 in a supercritical state as a solvent. The question is how to evaluate the performance of a new product such as Superwood™ in order to get an acceptance on the market and fulfil the formal requirements. In the European Union countries, the EN 599-1 is the standard that needs to be complied when approving a new product for the market, but it only focuses on the toxic limit against representative decay fungi according to EN 113. However, decay test, above ground and other forms of field tests are optional, this is not in line with the traditional test philosophy in the Scandinavian countries. The open question is to which extent treatment to the level of the toxic threshold value also ensures a long service life and expected performance of the treated commodity. Superwood™ is evaluated using a strategy, in which basic laboratory tests are done to get the toxic value (according to EN 599-1) and in addition a number of field tests are done including accelerated testing in the tropics. These tests are focussed on the evaluation of the performance criteria such as durability and service life and maintenance requirements. These questions must be answered by the producer without having a full record of performance test for their new products. A short status on the test performed on super-critical treated wood (Superwood™) is presented. Based on a comparison between field test in Scandinavia and in the tropical Malaysia a service life of more than 25 years for a specific supercritical treated product is estimated. It is stated that the existing European standardisation system is insufficient when it comes to service life prediction. A number of important questions need to be addressed by the European standardisation system as soon as possible because the market and the public opinion change quickly due to environmental concern.
N Morsing, A H H Wong, F Imsgard, O Henriksen


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


Conforming to european standards for preservative-treated timber: Specifying with confidence
2000 - IRG/WP 00-20194
A four-year collaborative study between four industrial partners and BRE has assessed timber treated by current UK industrial practices in the light of current European Standards. Data were collected for CCA and creosote treated timber components, and compared with the requirements laid out in EN351-1 and -2. A number of difficulties were encountered that have been described in previous IRG papers (98-20150, 99-20156), such as the poor reproducibility of chemical analyses and variable timber density. This paper describes the conclusions of our collaboration, focusing on the application of the findings and how to overcome any difficulties encountered. The data collected allowed the calculation of figures that have been submitted for inclusion into the UK's proposed national code for preservative-treated timber (DD239). An example is the recommendation of new minimum retention figures for creosote-treated commodities. This paper describes the factors that will enable UK specifiers to use the European Standards with confidence and greater understanding of how they map onto traditional methods of specification. In addition valuable lessons have been learnt applicable to the industry world wide.
E D Suttie, R J Orsler


European standardization for wood preservation
1988 - IRG/WP 2321
G Castan


European standardization for wood preservation
1990 - IRG/WP 2359
G Castan


Wood preservation in East European countries
1989 - IRG/WP 3527
The paper discusses the main problems of wood preservation in Bulgaria, Czechoslovakia, German DR, Hungary, Poland, Rumania and the USSR. The main types of wood preservatives produced have been presented, as well as the state of standarization to test their properties. There have been considered methods of wood treatment in use and application range of treated wood.
J Wazny


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


European laboratory termite testing
1986 - IRG/WP 1299
As with all testing of wood preservatives the evaluation of the resistance to termites of treated wood requires methodology which is approriate to, and can be readily extrapolated to, the practical situation. Thus not only must the variations in possible treatment systems be taken into account (eg dip, brush or pressure application) so too must the range of termite species and the type of exposure of the treated wood (eg ground contact, internal or cladding). The European need for the testing of wood preservatives against termites is two-fold. Firstly there is a need to assess protective treatments against the termite hazard in Europe itself; this concerns only two naturally occurring subterranean termite species Reticulitermes lucifugis and Reticulitermes santonensis, as well as one introduced species Reticulitermes flavipes. Although the dry wood termite Kalotermes flavicollis does occur it is not regarded as a serious building hazard. Secondly there is a demand by preservative manufacturers or users for assessment of the termite resistance of formulations or treated materials exported to countries with substantial termite problems.
R W Berry


The treatment of Douglas fir fence posts: specification and compliance using new European standards
1999 - IRG/WP 99-20178
New European standards for the preservative pre-treatment of timber require the results of the treatment process to be specified and subsequently verified by examination of the treated timber for penetration and retention of the preservative. For penetration, the standards are restrictive in that there are only a limited number of options available to the specifier. Thus for ground contact service, the appropriate option is full sapwood penetration. This paper describes a study in which the ability to meet a results specification for full sapwood penetration of Douglas fir fence posts with CCA was examined by treating 500 fence posts using a vacuum/high pressure process. When all treated fence posts were examined it was demonstrated that full sapwood penetration was not always possible. However, by applying different sampling systems linked to "acceptable quality levels" it was possible to develop an inspection scheme that ensured that batches of fence posts treated to the best achievable level were accepted under a full sapwood penetration specification. However, it was demonstrated that such a system would also allow some sub-standard batches to be accepted.
R J Orsler, H Derbyshire


Research on wood protection at the Princes Risborough Laboratory 1975 & 1976
1977 - IRG/WP 3109
This paper is the latest of a 2-yearly series presenting a summarised account of the Laboratory's work in wood preservatives and related fields. The topics dealt with include: environmental studies on the usage of copper-chrome-arsenic and organic solvent preservatives; development of National and International Standards; recent developments in the preservation of external doors and windows including remedial treatment of incipient decay in-situ; preservation of motorway fencing; distribution of house longhorn beetle; formulation of insecticides; permanence of preservatives and protection by finishes and coatings. A full list of publications for the period is appended.
J M Baker, R A Laidlaw, E R Miller, J G Savory


European standardization for wood preservation. Progress report 91-92
1992 - IRG/WP 92-2398
Since the IRG 22 conference in Kyoto, CEN/TC 38 Plenary met twice in relation with several working group meetings. 5 upon 6 of the interpretative documents have been prepared by adhoc groups of the Standing Committee for Construction within the scope of the 89/106/EEC directive on Construction Products. The expected requirements attached to wood preservation are both requirements 1) and 3): 1) mechanical resistance and stability; 3) hygiene, health and the environment. A consequence should be a redrafting of the previous official mandate delivered on September 27, 1989: - direct mandate on wood (solid and reconstituted) as well as wood preservatives as construction products - horizontal joint-mandates on wooden-commodities in relation with the other TCs in charge of such commodities. Another consequence is a formal exploration by TC 38/WG 11 "Permanence of active ingredients in treated timber" through a first couple of standards entitled "methods for measuring losses of active ingredients and other preservative ingredients from treated timber - Part 1: Laboratory method for measuring losses by evaporation to air - Part 2: Laboratory method for measuring losses into fresh water or salt water". This works anticipates the mandate and means that TC 38 is currently making progress, towards air and water quality. Apart from building activities, TC 38 got also by the end of 1991 an order of standardization on Creosote, and Creosoted-timber following the 13th adaptation of 76/169/EEC Diretive Creosote specifications. This additional event results from the trend in Brussels to develop the so-called "new approach" where the EC authorities elaborates essential requirements with mandates to CEN explicit them in close cooperation with the industry.
R Hüe


Specifying preservative-treated resistant timber: Conforming to European Standards
2001 - IRG/WP 01-20235
The most common construction timbers used in the UK are of low natural durability and, generally, resistant to preservative treatment. These include species of spruce, hemlock and fir. However, their characteristically limited and non-uniform uptake of preservatives may still confer sufficient protection to give satisfactory durability performance in terms of biological resistance. This paper describes the results of a study investigating the protective efficacy of treatments defined according to the approach in European Standard EN 351-1 when penetration and retention values are used in timbers showing non- uniform treatment characteristics. The data show that variation between batches of samples is high for preservative uptake, retention and penetration. The biological data have given indications that this leads to differences in performance effectiveness. However, the bioassay method developed does not in its present form, sufficiently discriminate between treatment/species combinations.
E D Suttie, A F Bravery, T B Dearling


Conforming to European standards on preservative treatment
1998 - IRG/WP 98-20150
New European standards require that specifications for the preservative treatment of timber are written in terms of the penetration and retention of preservative within the treated commodity that result from the treatment process. In order to check compliance with this type of specification, suitable methods of quantitative analysis must be available. This paper presents the results of a study by BRE and four commercial companies on the methods currently used in the UK to quantify the retention of CCA and creosote in treated timber. When analysing CCA-treated wood, different retention values were obtained with different methods of analysis and even with the same method when different operating parameters were selected. It has been concluded that either a single agreed method of analysis for CCA within Europe is required or more precisely defined operating conditions are required for each instrumental method which includes a method verification procedure. Data from traditional methods of assessing retention of creosote in transmission poles (e.g. charge volume uptake and weight differences) did not coincide with retention values obtained by quantitative analysis using the method in the European prestandard proposed as the reference method for creosote retention determination. Direct quantitative analysis of creosote treated timber selected from single charges showed large variations in creosote retention. It was concluded that recommendations for sampling in EN 351-2 do not take proper account of retention variations within a treated component nor of the difficulty in obtaining an analytical sample from a component once selected for examination. Greater care should be taken in defining the location within a component from which an analytical sample should be taken. In addition, a representative value for density is required in order to convert preservative content, determined as m/m from analysis, to the units used to express retention (kg/m3). This cannot easily be obtained and it is recommended that retention be expressed in m/m terms.
E D Suttie, R J Orsler


Overview of European discussions on Standardisation and list of proposed standards for WPC performance qualification
2006 - IRG/WP 06-20345
The standardisation is a driving force to promote the development of Wood Polymer Composites (WPC) by giving confidence to users and consumers. In Europe, the high interest of WPC require at this time a diffusion of information concerning the performances of WPC products. The WPC performances must be assessed according relevant standards in order to qualify the intrinsic properties of WPC (mechanical properties, physical properties, durability, …). WPC processing and environmental aspects must be taken in account. A CEN/TC 249 WG 13 "Wood Plastics Composites (WPC)" have been created in 2005. In France, a French Standardisation committee BNPP/BNBA T54 W has been created in France in 2004, jointly by the BNPP (Bureau de Normalisation des Plastiques et de la Plasturgie) and the BNBA (Bureau de Normalisation du Bois et de l'Ameublement). A high interest of French companies from the two sectors have been observed. An overview of European discussions on Standardisation and list of proposed standards for WPC performance qualification are discussed. Following discussions in very at European level will be to define a list of suggested standards elaborated to qualify plastics and wood-based products and to propose relevant standards to qualify WPC. Current discussions are on going at this time in CEN/TC 249 WG13 and in French standadisation committee T54W to select and to propose change of the standards (ISO standards, EN standards and other document) in order to purpose test methods for characterisation of WPC material and products. Future works will be done in 2006 to validate these documents and to purpose standards.
G Labat, M Vernois, T Gay


Further discussion of biological durability assessments of acetylated wood from several European institutes
2006 - IRG/WP 06-40340
In the last decade, interest in the development of wood modification systems has increased in Europe. Alongside several industrial initiatives for heat treatments, there have also been scaling up and pilot plant projects for chemical wood modification. Between 2000-03, the European Commission funded the "Thematic Network on Wood Modification". This paper features a re-evaluation of work undertaken within that project, assessing the performance of acetylated radiate pine. This re-evaluation comes at a time when acetylated radiate pine is due to be commercially launched. This corresponded with one of the key decisions of the Network, in that modified wood should be regarded as a new wood species, and tested accordingly, with particular emphasis on biological durability and dimensional stability.
D Jones, W Homan, F Bongers


Development of boron/linseed oil combined treatment as a low-toxic wood protection. Evaluation of boron fixation and resistance to termites according to Japanese and European standards
2007 - IRG/WP 07-30448
Combinations of boric acid as a first step of treatment and linseed oil as a second step have been performed in order to enhance boron retention to leaching and wood resistance to termites. Classic leaching and termites resistance standards are inappropriate to evaluate this combination which can be considered as both a wood core preservation treatment and a coating. Japanese Industrial Standard (JIS K1571, 2004) on Japanese cedar (Cryptomeria japonica) Japanese beech (Fagus crenata) exposed to subterranean termite Coptotermes formosanus, and, European standards EN84 and EN117 on Pine (Pinus sylvestris) exposed to termite Reticulitermes santonensis have been performed for the same boric acid/ linseed oil treatments. Addition of oil as a water repellent to boron treated wood gave promising results with about 30% of initial boron retained. Termite mortality rates and efficiency thresholds using the different standards are determined and compared. Moreover, the relevance of Japanese mass loss indicator and European visual evaluation are discussed in the case of unconventional wood protection system such as boron/linseed oil combination.
F Lyon, M-F Thevenon, Y Imamura, J Gril, A Pizzi


Performance classification of wood in construction – drafting a user friendly European standard
2014 - IRG/WP 14-20545
The performance classification for wood products in construction is an extremely important topic in Europe and beyond – warranty providers and end users demand service life and performance information in the face of competition with other materials. The European project PerformWOOD has formalised and drawn together the on-going research to focus on generation of a material resistance factor for performance classification and alongside WG28 is developing the first moisture dynamic test protocols in the Technical Committee’s history, again based on research work being drawn together. In this paper some of the early concepts around a future user friendly standard to enable wood and enhanced durability wood to be specified by construction professionals on the basis of performance are considered. A draft standard (EN460) for consideration of performance classification of wood in construction is underway and relies on concepts that are being road-tested with industry, construction professionals, researchers and the general public.
E Suttie, C Brischke, L Meyer, J Van Acker, M Kutnik, E Heisel, F Englund, J Jermer, S Thelandersson, M Polášek, D Lorenzo


Towards durability classification of preservative treated wood – first attempts using different European standards
2018 - RG/WP 18-20638
EN 350 (2016) gives guidance on methods for determining and classifying the durability of wood and wood-based material against biological wood destroying agents. “Wood-based materials are those derived from trees and include amongst others: untreated wood, heat treated wood, chemically modified wood, glue laminated wood, wood-based panels, wood polymer composites and wood treated with wood preservatives”. Very few data are yet available for assigning durability classes to preservative treated wood on the basis of results from test methods referred to in EN 350 (2016). In this study results from tests according to EN 113 (1996), ENV 807 (2001), and EN 252 (2014) were evaluated, for assigning durability classes of differently preservative treated wood, using different classification schemes. Specimens made from beech (Fagus sylvatica) and Scots pine (Pinus sylvetris) were treated with four different retentions of two wood preservative systems. Results show, that different tests lead to durability classification between 1 (very durable) to 5 (not durable) for same tested combinations. Most treated wood achieved higher durability classes based on test against basidiomycetes (EN 113) compared to tests against soil inhabiting micro-organisms (ENV 807 and EN 252). In summary, it became evident that durability classification of preservative treated wood strongly depends on both, the applied test method and the evaluation scheme used for assigning durability classes.
S Bollmus, A Gellerich, C Brischke, H Militz


Durability of tropical species from Peru according to European Standards
2020 - IRG/WP 20-10964
Natural durability is defined as the intrinsic resistance of wood against the attack of destructive organisms. There are standardized methods to estimate a durability value. In Europe, the standard EN-350 is responsible for establishing the basic guidelines, as well as the necessary tests to determine this value, which is essential to know the degree of protection needed for the tested wood to extend its service life. This standard applies to commercial wood, both native and imported, and helps to improve and obtain better construction applications depending on the final use of the wood. However, there are many species, including tropical ones, for which there is no or little information available. In this work, the natural durability of four timber-bearing Amazonian species from Peru - Calycophyllum spruceanum Benth, Schizolobium excelsum Vogel, Matisia cordata Humb, et Bonpl, and Cedrelinga cateniformis Ducke - have been studied against the attack of xylophagous fungi and termites compliant with the current European regulations. The results show that these species are durable, a fact that opens up a potential market in South America to export this timber to Europe. The data obtained will be incorporated into the European standard EN-350, given that there is no information on these species in it, with the exception of C. catenaeformis
J Valdivia, P Gómez, M T Troya, L Robertson, J A Martín, A Loayza


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


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


IRG - wood preservation - annual report 1999; wood preservation in Slovak Republic
2000 - IRG/WP 00-40192
This report gives basic information about wood preservation in Slovak Republic, related to the wood preservation research and education, to the most important wood-destroying organisms, to the wood preserving industry, and also to the problems of standards, market and environment.
L Reinprecht


European Biocides Directive (98/8/EC): Programme for systematic examination of all active substances of biocidal products on the market on May 13, 2000 Article 16(2)
2001 - IRG/WP 01-50166-03
PPT-Presentation
K Rasmussen, A B Payá Pérez


Developments in the protection of wood and wood-based products
1980 - IRG/WP 340
Technology is playing an increasingly important role in the field of wood protection. This current review highlights how modern techniques have provided greater insight into the biological and physical processes affecting the durability of wood and wood-based products. Emphasis is also given to developments in preservative testing methodology and to the encouraging changes towards both the correct use of timber and the improvement of Standards and Codes of Practice. A final section, on recent technical developments in wood preservation, considers subjects ranging from an evaluation of new specific biocides to methods of increasing the permeability of refractory timber species.
J M Baker


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