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Performance based specification of wood – Introducing project CLICKdesign
2019 - IRG/WP 19-20661
This paper introduces the new ForestValue research project CLICKdesign – delivering fingertip knowledge to enable service life performance specification of wood. This European consortium is working on the primary innovation to move from the complex, fragmented and general to the easy-to-use, consolidated and specific by provision of an accessible digital tool for specifiers. Competing materials tackle this and provide designers and architects with software. The specification of performance of wood products is highly complex and fraught with uncertainty, inconsistency and requires use of multiple platforms for data, experience, standards and national recommendations. CLICKdesign will provide a tool that has embedded within it the decades of excellent research, the complexity of the standards specification systems and the variation of approach due to tradition, materials and culture across Europe and beyond. A simple tool for non-expert public users will be available as well as a tool accessible to professional users that will be refined with industry to ensure relevancy and accelerate uptake and use. The project runs for 3 years from the 1 March 2019 and looks forward to contributing to the IRG debate now and in future.
E Suttie, C Brischke, E Frühwald Hansson, S Fortino, J Sandak, M Kutnik, G Alfredsen, C Lucas, R Stirling

Possibility of use of wood species per class of biological risks. Attempt to determine criteria based on Pr EN 350-1/2/3
1992 - IRG/WP 92-2409
M Rayzal

Draft Business Plan of CEN/TC 38 - Durability of wood and wood-based products - Introduction
2000 - IRG/WP 00-20207
CEN Technical Committees and Business Planning. The extension of formal business planning to CEN Technical Committees (CEN/TCs) is an important measure which forms part of a major review of business processes (known as 'Optimization'). The aim is to align the CEN work programme with expressed market needs and to ensure the adequate resourcing of projects through their development stages in the CEN/TCs. Your role in the implementation of the Business Planning concept will contribute significantly to the overall effectiveness of European standardization. We express our sincere appreciation and thanks for your time in reviewing this Business Plan.
R Hüe

The effect of storage or simulated internal use on the durability of wood based panels to decay fungi
1997 - IRG/WP 97-20106
Wood based panels such as particleboard and medium density fibreboard are experiencing a steady increase in use, in areas from structural to decorative applications. Understanding the "natural" durability of these panel products against basidiomycete fungal decay is therefore of great importance. Various methods have been proposed or are under development to test the durability/susceptibility of various panel products to decay. Our research has shown that if the fungal exposure methods detailed in the current European pre-standard (DD-ENV 12038:1996) are used to test boards fresh from manufacture, the susceptibility ratings observed are significantly lowered by the buildup of inhibitory substances in the test vessels. The effects of storing the boards before testing, in order to remove this effect have been studied with repeat biological tests carried out at intervals of 6 months. Our results show that even after 6 months storage the effect is reduced but not totally removed. The time after manufacture and the storage conditions are clearly significant variables affecting the "durability" of test specimens taken from the boards and therefore the incorporation of an appropriate preconditioning stage into the test is essential so that the effect is avoided.
S F Curling, R J Murphy, J K Carey

Work program of CEN/TC 38 (April 1993). Durability of wood and wood-based products
1993 - IRG/WP 93-20012
R Hüe

Flow charts for termite and decay tests to determine the natural durability of Japanese cedar (Cryptomeria japonica D. Don)
2008 - IRG/WP 08-20385
This paper deals with the experimental flow charts that were used for determination the effects of fungal decay and termite attack on Sugi heartwood during the course of the study of “Comparative studies of natural durability of Japanese cedar (Cryptomeria japonica D. Don) among the geographic cultivate”, which was carried out by Usta et al (2006).
I Usta, S Doi

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

Evaluating the resistance of wood-based panel products to fungal attack
1995 - IRG/WP 95-20071
At present there is considerable disagreement among national research institutes within Europe and panel product manufacturers on the most appropriate method of testing and indeed the need for specific biological durability testing. This paper seeks to place before a broader international audience, the issues related to development of a European standard for evaluating the resistance to fungal decay of wood-based panel products. It rehearses the particular issues which need to be addressed. In particular it identifies as problems to be resolved, pre-conditioning of test samples to remove transient leachable/volatile preservative components, choice of weight loss or strength loss as efficacy criteria, and appropriate sampling levels.
R G Lea, R W Berry

The effect of alternative pre-conditioning procedures on the durability of wood based board materials to decay fungi
1997 - IRG/WP 97-20105
In the biological testing of wood based board materials it has been shown that exposure of boards in a closed vessel system may lead to inaccurate results due to the build up of volatile substances that inhibit the test fungi. It is thought that this is a transitory effect of freshly manufactured boards. In the European standard for testing fungal durability of board materials which is currently under development (DD-ENV 12038:1996), a leaching pre-conditioning method is used to remove this effect. A variety of alternative ageing procedures have been studied, including natural weathering, leaching and evaporative procedures, to determine the most appropriate pre-conditioning protocol for the decay test. Our results show that there are procedures which are more efficient, and possibly more meaningful in terms of effectiveness or appropriateness of regime for use on board specimens.
S F Curling, R J Murphy, J K Carey

Laboratory Evaluation and Field Trial of Chlorothalonil and Copper-based Preservatives and Leaching Performance of Copper in Copper Treated Wood
2002 - IRG/WP 02-30279
Soil block test and field trial of some Chinese plantation wood species pine and poplar treated with chlorothalonil formulations and copper-based preservatives such as ACQ-B and copper citrate (CC) were conducted. The results of soil block test indicated that chlorothalonil formulations and ACQ-B as well as CC are very effective for controlling the 2 fungi species Corious versicolor and Poria placenta at different retention. There is no significant difference of weight loss among retention level range 2.54-23.1 kg/m3 of ACQ-B and CC in our test. The durability of wood treated with chlorothalonil oil formulation is better than that of treated with emulsion formulation. ACQ-B and CC treated wood at different retention level are effectively resistant to decay and termite after 36 monthr field trial at Guangzhou, south China. Leaching rate of copper of CC treated wood is much higher than that of CCA and ACQ-B treated wood by the 2 wood species Pinus massoniana and Eucalyptus urophylla according to AWPA standard M11-87.
Mingliang Jiang, Ping Wang, Chungen Piao, Zhaobang Li, Quan Lu, Lei Liu

Termite resistance classification of some tropical and temperate species based on the laboratory choice test results against formosan termite, Coptotermes formosanu
2004 - IRG/WP 04-20291
The results of classification of termite durability were varied. We carried out laboratory evaluation of the classification of termite durability on various species by the choice test against formosan termite, Coptotermes formosanus. We classified five grades (very sensitive to very resistant). According to our results, azobe, ipe, keruing, intsia, kapur, yellow meranti, jarraah, malas, cypress pine, alaska-cedar, hinoki and hiba, were indicated rather high termite resistance and four species, siberian red pine, teak, terminalia and gmelina, were shown very variable termite durability.
K Suzuki

Preliminary investigation on the natural durability of Guayule (Parthenium argentatum)-based wood products
2000 - IRG/WP 00-40154
Conventional preservatives used to protect wood from insect and microbial damages are presently of major concern to human health and the environment. Finding alternative and economical preservatives has not been successful. Previous studies have shown that the resinous material extracted from the guayule plant (Parthenium argentatum, Gray) has both insect- and microbial-resistant properties. Unfortunately, it has not been accepted commercially because of the lack of an adequate supply of the raw material. However, the potential domestication of the guayule plant to produce hypoallergenic rubber latex will result in the production of large amounts of waste wood material. This should provide opportunity to use this natural source of the biologically resistant resinous chemicals. The objective of this preliminary study was to determine the effects of the rubber latex-removed wood residues or bagasse and the resinous extracts on termite- and decay-resistant properties. Two types of test materials were used in the study. One was wood impregnated with organic-solvent extracted resinous material from the plant. The other was composite wood fabricated using the residue or whole plant and plastic binder, which was used to improve the physical properties of the composite. Accelerated laboratory tests were conducted to determine the resistance of the wood products against the Eastern subterranean termite and wood fungi (brown-rot). The wood and stem of the guayule plant, wood treated with the resinous extract, and particle and composite wood made from ground guayule exhibited termite and wood fungal resistance.
F S Nakayama, P Chow, D S Bajwa, J A Youngquist, J H Muehl, A M Krzysik

How to win friends and influence the market — Service Life Prediction and performance-based durability assessments of wood products in construction
2006 - IRG/WP 06-20348
Due to direct and implied demands from the market and from e.g. the EU Construction Products Directive, the need to supply service life estimates for building products is growing. For several years, a development of Service Life Prediction (SLP) methodologies has been going on, but the awareness of this development has hitherto reached only a very limited extent in the wood sector. For materials whose degradation in service is governed by not only physical factors but also, and in many cases to a dominating degree, by biological mechanisms, acurate service life estimates are particularly difficult. Still, in order to defend and expand the market for wood products in construction in the long run, it is of great importance that durability assessments are transformed and expressed in ways that are truly useful for specifyers and users. More clearly stated: The needs and the interests of the user should be in focus and should be the actual starting point for development of both products and durability assessment methods. An initiative to bring this discussion to the CEN Committee TC 38 “Durability of wood and wood-based products” has led to the formation of a Task Group, which will further look into the possibilities to incorporate SLP methods in European durability standards. This development has been carried into effect by the establishment in 2004 of a Task Force within the COST Action E 37 “Sustainability through new technologies for enhanced wood durability”. The Task Force has made preliminary work, making inventories of methods for testing and assessment, analysing the purposefulness of these methods, and giving some outlines for a future performance-based system of classification of wood products. The Task Force will give a final report of its work later this year.
F Englund

The Development of a novel method to preserve reeds using an environmentally friendly timber preservative and a unique engineering design.
2006 - IRG/WP 06-40335
Reeds are used in the construction of bush lodges in Northern Kwa- Zulu Natal, South Africa. Fungal, insect and ultra-violet damage to these reeds is posing a severe problem. Within a space of two years, the reeds are attacked and have to be subsequently replaced; a time consuming and costly exercise. A novel method has been used to successfully preserve these reeds with an environmentally friendly preservative containing disodium octaborate tetrahydrate in a water-based polymer system. The polymer allows for uninhibited diffusion of boron into the reeds, whilst the polymer cures to form a continuous protective film. By making use of two strategically drilled holes, which are 2 mm in diameter, the preservative is introduced into the reed shafts and nodes. The boron successfully diffuses into the walls of the reeds and is prevented from leaching out of the reeds. The water-based polymer provides sufficient protection against excessive ultra-violet damage. The test site, which is situated in the Hluhluwe Game Reserve in Northern Kwa-Zulu Natal – South Africa, has been monitored for nearly two years and there are no sign of insect or fungal damage to the reeds. Over the two-year period, the reeds were periodically inspected for deterioration in colour and deterioration in structural integrity.
K Govender, K G Moodley

Categorization of 300 timber, bamboo and cane grown in Bangladesh based on their families, origins, growths, physical and mechanical properties
2009 - IRG/WP 09-10684
In this study the 300 timber, bamboo and cane plants grown in Bangladesh have been classified into various categories based on their taxonomic families, origin of species, rate of growth, color of wood, texture of wood, shrinkage of wood, equilibrium moisture content (EMC) of wood, flammability of wood, cutting and sawing properties of timber, finishing and polishing qualities of wood, machining properties of wood, nail holding capacities of wood, density of wood, natural durability of wood, seasoning properties of wood, treatability of wood and mechanical strength of wood. The information tabulated in an intact table along with local and scientific names are very useful to foresters, conservers, planters, users, researchers, industrialists, manufacturers of wood, bamboo and cane products, preservers, designers, architects, technologists, etc., for appropriate application of timber plants ensuring their considerable comparative production, conservation and protection.
A K Lahiry

Service life prediction of wooden components – Part 2: Impact of material, exposure and design details
2010 - IRG/WP 10-20440
Dose-response functions permit to estimate the moisture and temperature induced decay potential for any wooden building component and exposure, and thus the service life to be expected. In part 1 of this series dose-response functions were established as a result of double layer field trials carried out at 24 European test sites over up to eight years. Using them makes it no longer necessary to conduct field trials as long as decay actually occurs. They allow determining dose-time functions for a certain construction detail over shortened time periods (2 3 years). Within this paper we present the test set up of different studies aiming on quantifying the impact of material, exposure and design details on the service life to be expected for wooden components. Therefore long-term moisture recordings were applied to different wooden commodities, e. g. fence posts, pickets, decking, and facades. Furthermore, the impact of orientation, distance to the ground, and driving rain load on facade panels was studied. Finally dose-time functions will be recorded for ten different wood species used in horizontal and vertical orientation. First results from the various studies including preliminary service life estimation for various components are also presented.
C Brischke, B Lauenstein, M Bilstein, T Bornemann, A O Rapp

Decay hazard mapping for Europe
2011 - IRG/WP 11-20463
In this study, two different dose-response models for above-ground decay as well as a model transferring macro climate data to wood climate data are presented. The models base on data from field trials, which had been conducted at 28 European test sites, and were used to calculate the relative risk for decay caused by climate variability in Europe. The two dose-response models give coherent results when using either measured wood climate data or simulated climate data. The potential to simulate the relative risk of decay for different sites in the world from climate data has been demonstrated, even if no measured wood climate data is available. A preliminary decay hazard map has been generated to illustrate the climate induced variability within the European continent. For comparative purposes also the Scheffer Climate Index (SCI) had been applied to the same European data base. It was concluded that valuable information for service life prediction of timber structures will be gathered from performance-based decay hazard estimation and mapping.
C Brischke, E Frühwald Hansson, D Kavurmaci, S Thelandersson

Limited variability in biological durability of thermally modified timber using vacuum based technology
2011 - IRG/WP 11-40567
The SmartHeat® thermal timber treatment is a new technology based on the process parameters being steered very precisely mainly due to the vacuum applied and heating system involved. Timber treated with this technology shows a potential for less variability of biological durability in one batch. Several batch treatments were sampled and assessed on statistical variability of decay resistance against Basidiomycetes and soft rotting micro-fungi according to lab testing as described in the standards CEN/TS 15083 part 1 and 2 respectively (only Basidiomycetes test results are reported in this paper). By means of Weibull distribution assessment it was possible to show that variability in biological durability of each treated beam is well controlled and that this variability is limited compared to natural durability of wood species. Lower treatment variability due to precise parameter control for each beam and limited deviations of process parameters within the treating vessel are considered the main contributing factors. The paper also states that lower control of process parameters of some heat treatment processes might induce higher variability of the obtained biological durability than a customer might expect.
J Van Acker, S Michon, J Van den Bulcke, I De Windt, B Van Swaay, M Stevens

Moisture performance based wood durability testing
2012 - IRG/WP 12-20495
In the frame of a scientific cooperation within the Swedish research program ‘WoodBuild’ comparative field and laboratory durability studies have been carried out by the Technical Research Institute of Sweden SP and Leibniz University Hannover. One objective was to improve test methods as well as evaluation systems in order to facilitate the use of (field) testing for service life prediction. Therefore field trials containing long-term moisture and temperature recordings were set up to verify the suitability of different test methods for estimating the durability of wood under different exposure conditions. In this paper the test set up as well as preliminary results of the comparative studies on moisture performance of different materials in standardized and non-standardized field tests are presented. The field trials include graveyard, double layer, sandwich as well as lap-joint tests, which were performed with natural durable, modified and preservative treated timber. To consider the aspect that different climate conditions affect wood degrading processes the tests were carried out at three different test sites: Borås (Sweden), Hilo (Hawaii, USA) and Hannover (Germany). In addition, different laboratory decay and moisture uptake tests were conducted on samples matched to the field specimens. Preliminary results of the continuous moisture content (MC) measurements pointed on differences in moisture load between test methods, materials, and test sites. A more detailed understanding of the respective moisture regime can be expected when using different above ground test methods. Compared to traditional durability field testing the moisture performance based testing allows for reducing exposure intervals and more use-class related assessment. Due to this it seems worthwhile to quantify further test methods related to their severity and consequently to different exposure situations. The results for the different modified and preservative treated timber products pointed on the need for determination of material-dependent critical MC.
L Meyer, C Brischke, A Pilgård

Focus on the European standardization - Towards a revision of the EN 350 natural durability standard: a different approach to the inherent resistance and performance of wood and wood-based materials
2013 - IRG 13-10811
The European standard EN 350 “Natural durability of solid wood”, Parts 1 and 2, is one of the fundamental standards developed by the CEN/TC 38 “Durability of wood and wood-based products”. This standard is widely used by wood industries as the reference document which provides information on the resistance of wood species used in mainly the construction sector against decay fungi, wood-boring beetles and termites as well as information on wood species’ capacity to be impregnated with wood preservatives. The standard also refers to the appropriate standards for testing these properties of wood and provides criteria of interpretation of such tests’ results. The changes that have occurred over the last few decades on the European market, including the appearance of new wood-based products such as modified wood, the publication and application of new regulations (Biocidal Directive/Regulation, Construction Products Directive/Regulation) and the evolutions of customers’ expectations in terms of the service life of the wood-based products which they may use, make it crucial to initiate a deep revision of the EN 350 standard. The new version would take into account the revisions made recently in related existing standards, the modifications that have occurred on the European market of wood products, and the outcomes of recent national and European research projects in order to provide a robust and relevant decision tool to all those who rely on wood.
M Kutnik

Estimation of service life of treated wood in ground contact based on early indicators
2013 - IRG/WP 13-20536
A well-known problem with field testing is that it takes a long time before meaningful and reliable results are achieved. Only when a trial has come to an end the so called average life for the samples in a group can be calculated and compared with other samples. The aim of the present study was to investigate if it is possible to get a reasonable and good estimation of the average life long before a trial has come to an end. In order to get early stage results five early indictors were identified. Values for these indicators were calculated for a large number of trials. Estimated average lives (EAL) were calculated with help of single and multiple regression analyses and compared with actual average lives. The results are presented as ccoefficients of determination (R2) between the different early indicators and the average life of the trials as well as diagrams showing the calculated EAL compared to average life according to the standard EN 252. For some groups of test fields and preservatives the correlation and estimations are very good while they are worse in other cases. The study has confirmed that it is difficult to find a general method, based on early indicators, to estimate the average life of different types of preservative-treated wood tested in field trials according to EN 252. However, the calculation model is promising as in some cases the estimated average life shows a good correlation with the average life according to EN 252, which indicates that further efforts to improve the model seem worthwhile.
M Hansson, J Jermer, P Larsson Brelid, N Terziev

Moisture dynamics of wood – An approach to implement wetting ability of wood into a resistance classification concept
2014 - IRG/WP 14-20557
Within the research programmes WoodBuild and PerformWOOD, wetting ability tests have been conducted with 25 wood-based materials. A first attempt has been made to establish factors for calculating the material resistance of wood materials to be implemented into a design guideline for timber structures. The approach looks promising, but further studies are needed to establish more reliable relationships between laboratory wetting ability test results and outdoor moisture performance. It is also necessary to come to an agreement on how to determine the wetting ability as well as to get reliable data on the decay resistance for preservative-treated wood, modified wood and wood polymer composites.
C Brischke, C Hesse, L Meyer, S Bardage, J Jermer, T Isaksson

Moisture performance testing of wood – Practical experiences
2014 - IRG/WP 14-20546
Different methods are used to characterize the moisture performance of wood and to quantify the effect of moisture loads on the resulting service life. These methods can be divided into direct and indirect methods. Furthermore they can be distinguished by characteristics like continuous or periodical measurements and measuring local or global moisture content (MC). Furthermore each measuring method has certain peculiarities that need consideration when designing a test set up and conducting MC measurements in the field. Therefore this paper gives reports on practical experience with measuring and monitoring wood MC to determine the moisture performance of wood under lab and field conditions. It is composed of results from different studies that have been conducted during the last 4 years. The aim was to enhance the understanding of factors influencing gravimetric and resistance based MC measurements. The results of the different studies pointed on the potential of moisture monitoring to serve for an improved interpretation of field test data. However, they also highlighted the need for considering several significant factors.
L Meyer, C Brischke, M Kasselmann, C Rösmann

In-ground durability of wood-based products – Comparative assessment of graveyard field tests and terrestrial microcosms
2014 - IRG/WP 14-20538
Traditionally wood durability and the effectiveness of wood preservatives are determined in so-called graveyard tests (according to EN 252 or AWPA E7). For laboratory testing, terrestrial microcosms (TMC) can serve as an alternative. Both tests have been applied for different types of wood-based materials, preservative treated, modified and unmodified wood. However, the usability of laboratory results for predicting the performance of wood products under field conditions has been discussed controversially for a long time. With the purpose of profounder understanding, a comprehensive test was set up to compare re-sults from different laboratory and field tests considering the full range of wood based products. In total 34 materials (11 native softwoods, 5 native hardwoods, furfurylated, acetylated and thermally modified timber as well as different preservative treated timbers) have been exposed in ground at the test sites Borås, Sweden, and Hannover, Germany. Furthermore lab tests with TMCs have been conducted. Therefore an active compost soil producing high soft rot decay was used as well as the field soil from the two test sites to allow direct comparison. The mass loss obtained in the TMCs differed drastically whereby compost soil showed the high-est decay activity. Generally, the obtained mass loss was lower in the Borås soil compared to the soil from Hannover. However, this was not confirmed by the decay progress observed in the Bo-rås field, which was approximately equal to the activity in the Hannover field. Furthermore, some materials suffered from brown rot decay in the field which was absent in the TMCs, where moisture conditions were unfavourable for brown rot fungi. Different indicators and statistical measures were assessed with respect to their potential for pre-dicting the outdoor performance of the various wood-based materials. In spite of a general com-pliance between lab and preliminary field test results, a remarkable number of discrepancies pointed on the need for field tests representing all relevant types of decay.
A Soetbeer, L Meyer, C Brischke, P Larsson-Brelid, J Jermer

Moisture dynamics of wood and wood-based products – Results from an inter-laboratory test
2014 - IRG/WP 14-20539
In the frame of the European research project PerformWOOD in close liaison with the CEN task group TG EN 350 of CEN TC 38 WG 21 in total six research institutes teamed up and initiated an inter-lab trial (Round Robin) to investigate the suitability of different test methods to determine the wetting ability of wood. The moisture performance of wood and wood-based products has been recognized as key element in wood durability and wood protection. Actually it should be considered as major component of the material-intrinsic resistance of wood, but never found its way into a standardized test method. In this paper, the key results are presented from floating and submersion tests to determine the residual moisture after equal cycles of absorption and desorption, the water uptake and release after different 24h condition cycles as well as the capillary uptake in tensiometer tests and according to the Cobb method. Finally, the eight tested wood-based materials were ranked according to the various test set ups and compared with results from continuous MC recordings from different field tests. The potential of the different methods to predict the outdoor moisture performance of wood is discussed and recommendations for a future standard test protocol are given.
C Brischke, L Meyer, C Hesse, J Van Acker, I De Windt, J Van den Bulcke, E Conti, M Humar, H Viitanen, M Kutnik, L Malassenet

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