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A proposal for an international wood preservation standard
1994 - IRG/WP 94-20031
Two factors are driving the need for an international wood preservation standard. First, the global need to use our natural resources more wisely and second, the movement towards free trade exemplified by the General Agreement on Tariffs and Trade. The International Research Group on Wood Preservation is the ideal organisation to undertake the task of developing such a standard. This paper is intended to start this process. It attempts to bring together the best points of a number of national and international standards into a uniform format. Preservative penetrations and retentions for each commodity would be based on the hazard class/use category, the climate zone, the biological area, the natural durability of the heartwood of the species used, the service life required and the consequences of failure. The outline standard presented borrows heavily from the new European Standard and is presented as a possible starting point for the development of an international standard.
P I Morris


A note on testing the efficacy of wood preservatives above ground
1995 - IRG/WP 95-20078
A number of test methods have been used to evaluate the performance of wood preservatives in above ground situations. These have included EN 113 tests following natural exposure weathering (NEWT), L-joint or T-joint tests, lap-joint tests, and decking tests. A new test referred to as the A-frame test has been developed and is under evaluation. This is based on a sandwich-type test in which a thin (3.5 mm) sample is exposed outdoors between two untreated samples on a rack or A-frame. The advantages and disadvantages of these types of tests are discussed in a short note.
G R Williams, J A Drysdale, R F Fox


Practical consideration in developing an international hazard class standard: The hazards and risks
1996 - IRG/WP 96-20091
This paper discusses the concept of hazards and risks in relation to the way in which the hazard class philosophy may be used for international standardization. The difference between hazard and risk is considered as a basis for a simple classification of biological hazards for timber in use based upon its service environment. The paper proposes that the moderating influences within a service environment may be regarded as risks and used to classify the severity of hazard. These risks depend principally upon geographical location (climate) and design features controlled by the specifier. It is concluded that a pragmatic and simple approach could provide the best opportunity for an international agreement.
R J Orsler


Less environmental impact of wood preservatives by considering the risk of attack in addition to the hazard class system
1995 - IRG/WP 95-50040-10
Hazard classes, which are standardized in Europe in EN 335, are most useful to direct chemical wood preservation towards the organisms which may attack wood in the various fields of utilisation. However, hazard only signifies the fact that an attack may occur without considering the actual risk to attack. To minimize the application of chemicals with respect of less environmental impact it is necessary to consider both, the hazard of attack and the risk which implies the probability, how often attack may occur and how important this will be. In addition, also the consequences of the failure of a wooden commodity will influence the need of chemical wood preservation. It is therefore proposed to combine the hazard classes as specified in EN 335 or in similar non European regulations with a risk assessment including time assessment as a basis for the requirement on chemical wood preservation. For this, details are given in the paper.
H Willeitner


Assessing the performance of wood preservatives from biological tests - the European approach
1994 - IRG/WP 94-20040
The impetus for the European Standardisation Committee to undertake the development of a performance standard for characterising the effectiveness of wood preservatives from biological tests, lies in the Construction Products Directive. This is effectively the European Community law which provides the basis for Construction Products to be traded across all member states without technical or regulatory barriers and without having to undergo further testing or re-certification. The performance standard covering wood preservatives is EN 599 and it defines the performance which preservative products will be required to achieve in specific laboratory and field tests, in order to be accepted and marketed as suitable for particular conditions of use. Five hazard classes of use are defined in another standard (EN 355-1) and EN 599 lists the specific biological tests required for each hazard class, the maximum amount of the product that can be applied in each test, the need for pre-leaching or pre-ageing and the rationale for deriving a value (the biological reference value) for the minimum amount of product deemed effective in each test. The highest biological reference value determined from all the tests is defined as the critical value and it is this value which is carried forward to the standard covering treated wood (EN 351) to provide the basis for defining the minimum amount of product required for effectiveness within treated commodities. EN 599 lists the minimum testing requirements for each hazard class together with optional additional tests to provide efficacy assessment against a wider range of target pests or to increase confidence in the critical value by incorporating data from longer-term field tests. The standard also describes the requirements for marking and labelling preservative products to describe their suitability for specific uses. Work on EN 599 commenced in 1988 and its development has required negotiated agreement between the 18 member states of the CEN/CENELEC region with 12 different working languages and 3 different official languages for documentation. EN 599 is now at the final stage of submission to vote and the decision on its adoption and implementation will be announced before the end of 1994.
A F Bravery


Permanence of permethrin and bifenthrin in framing timbers subjected to hazard class 3 exposure
2005 - IRG/WP 05-30383
End-sealed Pinus radiata specimens measuring 235 x 90 x 35 mm were treated using a modified Lowry schedule with permethrin or bifenthrin in white spirit to Hazard Class 2 (H2) retentions. After conditioning, the specimens were exposed at 45o on north facing racks near Melbourne (Australia). Samples of the specimens were taken before installation, and after three and six months exposure. Analyses of permethrin-treated specimens revealed a considerable decrease (14-34 %) in permethrin content in the exposed outer 2 mm after 3 months. Continued exposure for an additional three months did not lead to further significant reduction in the permethrin retention of the outer 2 mm zone. Analysis of the 2-5 mm zone has shown no significant change in permethrin levels. The loss of permethrin is essentially confined to the outer 2 mm zone of the exposed surface which is thought to be caused by UV degradation and/or hydrolysis. Comparatively, bifenthrin exhibited no significant loss in the inner or outer samples, which maybe attributable to its greater chemical stability.
A C Hunt, D G Humphrey, R Wearne, L J Cookson


Towards a unified international hazard class system
1996 - IRG/WP 96-20081
Working party 2.5 on International Standardisation has set the development of a unified hazard class system as a short-term objective. This document is intended to stimulate the discussion required to work towards such a system. Two possible approaches are discussed, the compromise approach and the development of a basic system from first principles. For the second approach, the factors impacting on durability of wood products are examined and three factors are selected to define hazard classes. All three increase in number or severity with increasing hazard class. They are: the sources of moisture and nutrients and the inoculum potential of the primary biodeterioration agents. These describe the potential for a biodeterioration hazard. A unified international hazard class system is proposed.
P I Morris


Methods to determine the efficacy of three water repellent additives in waterborne preservatives
1997 - IRG/WP 97-30142
The paper describes the methods used to determine the efficacy of three different water repellent additives in waterborne preservatives. The wooden samples used are pine (Pinus sylvestris) and spruce (Picea abies) that are treated with 9 different waterborne preservatives in retention for hazard class 3 (above ground commodities). There are two sample sizes exposed, cladding boards (19 x 148 mm) with a sawn surface exposed 60 ° facing south, and decking boards (21 x 95 mm2) with a planed surface exposed horizontally. The boards' dimensions have been measured and water repellent properties have been checked three times with water droplets during exposure in 2.5 years. During the winter 1996/1997 and spring 1997 we have logged the temperature and moisture content in eight of the boards for one of the additives; also with and without preservative (CCA). We log every half hour. The RF is also logged. This paper will in addition to describing the methods also give the results after 2.5 years, while a subsequent paper will give the results for the efficacy of the different additives.
F G Evans, B Nossen, K M Jenssen, L R Wilhelmsen, G Fuglum


Aquatic toxicity research of structural materials
1998 - IRG/WP 98-50114
Continuing from preliminary results reported on the aquatic toxicity of some tropical hardwoods under high hazard conditions, a more comprehensive research study is set-up in order to assess the environmental toxicology of various structural materials in water applications. Hazard class 4 preservative treated wood is tested for its toxic response on a battery of aquatic test organisms, next to concrete and plastic and a selection of tropical hardwoods used in waterworks. The results reveal a wide range of toxicity responses covering tropical and treated timbers, the alternative materials bearing a considerably lower toxic profile. Still, a general observation is found in the enhanced inhibition of algal growth for all structural materials.
G M F Van Eetvelde, S De Geyter, P Marchal, M Stevens


The use of organic wood preservatives in ground contact and the suitability of laboratory test procedures to determine their efficacy
1999 - IRG/WP 99-20175
Organic fungicides, such as propiconazole, have proven to be highly effective when used as a co-biocide in recently developed wood preservative formulations. They have however been ineffective when used as a stand alone preservative, particularly when used in ground contact (European Hazard class 4). Previous research, using the test methods of ENV 807 (1993), provided conflicting evidence regarding the efficacy of propiconazole when used in a ground contact situation, with the preservative appearing effective when tested using the vermiculite test and ineffective when using soil burial. This paper considers the use of the existing methods of this European Standard for use in the research and development of organic fungicides, and compares alternative micro-fungal spore combinations to that stated in EN 807 (1997) with the aim of improving test performance.
I J Herring, D J Dickinson


Performance of softwood preservative treated stakes after 4 years exposure in-ground to decay fungi and termites in tropical Australia
2008 - IRG/WP 08-10643
This field study was based on the 1993 IUFRO method and designed as a graveyard (in-ground) test in the tropical region of the Northern Territory to examine the efficacy of novel preservative formulations developed as alternative protection for softwood timber against decay fungi and termites for Hazard Class 3 and 4. This study was supported by the Forest and Wood Products Research and Development Corporation (FWPRDC). Timber specimens 500 (longitudinal) x 50 (tangential) x 25 (radial) mm were cut from the sapwood of fast grown Pinus radiata D. Don and treated with trimethylborate (TMB), sodium octoborate, linseed oil and fipronil in various solvents (toluene, linseed oil and deionised water) using a vacuum/pressure treatment method. After 4 years in-ground, the solvent control and fipronil (only) treated stakes were slightly attacked by soft rot, brown rot and white rot fungi. Most of the stakes had surface damage only, while few of the solvent controls had severe damage by only decay fungi. There was slight attack on the treated timber by soft rot fungi. A small number of solvent controls and borate treated stakes were severely attacked by subterranean termites, particularly Coptotermes acinaciformis (Froggatt). The fipronil only or fipronil with borate treated stakes were not attacked.
B M Ahmed (Shiday), J R J French, S R Przewloka, P Vinden, J A Hann, P Blackwell


Glueline fungicides in veneer based engineered wood products - results from laboratory work for the H1.2 hazard class in New Zealand
2012 - IRG/WP 12-30593
The use of glueline insecticides in plywood and laminated veneer lumber is commonplace in several countries. However, few glueline fungicides are registered for commercial use with previous work suggesting that achieving control of decay from the glueline is very challenging. This paper summarises two tests completed on Pinus radiata plywood with a new glueline fungicide comprising the active ingredients triadimefon and cyproconazole (Triad/Cypro). Tests were completed in New Zealand using a bin method to satisfy the requirements for the H1.2 hazard class (wet area framing). In both tests, Triad/Cypro in the glueline of plywood restricted decay growth comparably or better than the recognised reference preservative of propiconazole plus tebuconazole applied as a light organic solvent preservative treatment.
A Siraa, K Day, P Lobb


System treatments of Pinus sylvestris - influence on moisture, decay and discoloration
2013 - IRG/WP 13-30612
Biological activity can cause challenges for the use of wood in outdoor exposure. Decay and discolouring fungi influence the service life of wooden constructions, and the moisture content of the wood is often an important factor. The aim of this study was to evaluate the performance of different combinations of preservative/modified wood protection treatments and surface treatments for wooden decks in different exposure situations after ten years of field testing. Fourteen different wood protection treatments were tested, in addition to Scots pine sapwood, Scots pine heartwood and European larch heartwood. Furthermore two different surface treatments were included (alkyd oil with iron oxide pigments (AO) and alkyd emulsion without pigments (AE)) in addition to no surface treatment. The test setup used was the “Stapelbädds metoden”. The bottom layer is in soil contact and this stack method provides a moisture gradient within the five layers included. As expected a gradient of increasing wood moisture content and fungal decay rating was found from the top layer to the bottom layer of the stack. For samples with no surface treatment the treatments with lowest wood moisture content was Styren, Tanalith E7, Royal with pigment, European larch heartwood and thermal modification. In the stacks without surface treatment Royal with pigment and Gori SC 100 were the only treatments with decay rating ≤ 1 in all layers, while Scots pine sapwood, Scots pine heartwood and UltraWood all had decay ratings > 2 in all layers. AE surface treatment decreased fungal decay in all layers for furfurylation, Scots pine heartwood and Tanalith M. A similar trend including all layers was not found for AO. All treatments were totally covered by discolouring fungi with the exceptions of ACQ 1900 and Scanimp. Among the untreated samples European larch heartwood generally gave the best performance. The results show that moisture content and fungal decay rate can be reduced with the support of a surface treatment, but they also showed that the opposite can also be the case after ten years of field exposure.
A Schabacker, G Alfredsen, L Ross Gobakken, H Militz, P O Flæte


The development of accelerated test systems to evaluate the durability of framing timber
2014 - IRG /WP 14-20547
Various accelerated decay resistance trials including small simulated wall units, samples exposed in enclosed tanks and ‘I’ samples in stacks have been explored and used to test the durability of treated and untreated radiata pine framing at Scion since 2001. These testing methods have been established to determine the effectiveness of commercial formulations in preventing decay in framing subjected to intermittent wetting. These are relatively short term test methods requiring a minimum of 12 months testing. Results of these tests have been used to develop suitable preservative formulations and retentions for Hazard Class H1.2 for inclusion in New Zealand Standard for Chemical Preservation of Round and Sawn Timber (NZS 3640). In New Zealand framing hazard Class H1.2 is for timber which is protected from the weather, but with a risk of wood reaching a moisture content conductive to decay. In this communication, we discuss the advantages and disadvantages of these test methods.
T Singh, D Page, J van der Waals


Glueline fungicides in veneer based engineered wood products – updated results from laboratory work for the H1.2 hazard class in New Zealand
2018 - IRG/WP 18-30726
Results from New Zealand H1.2 ‘bin’ trials containing plywood glueline treated with triadimefon and cyproconazole were reported in 2012 (IRG/WP 12-30593). One of these trials has continued to the present day (2108) and updated results of this trial are reported. The triadimefon and cyproconazole glueline treatment continues to compare with, or outperform, the reference preservative used, being propiconazole and tebuconazole applied as a light organic solvent preservative treatment.
A Siraa, K Day, B Kibby


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


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


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


Wood Preservation in France. A statement of quality control early 1986
1986 - IRG/WP 3389
A statement of quality control in France early 1986 - Summary of new - Standards criteria for preservatives and treated wood - Aptitude of treated wood for use per class of biological hazard
M Romeis, G Ozanne


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


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


A risk model for termite attack in Australia
2003 - IRG/WP 03-10468
This paper describes a model to predict the risk of termite attack on a house in Australia. It is based on a survey of expert opinion and data from 5000 houses. The model gives a quantitative estimate of risk, and as such is useful for the development of risk management systems. An example of the application of such a system is given.
R H Leicester, C-H Wang, L J Cookson


Japan's comments on ISO/DIS 12583-1/2
1996 - IRG/WP 96-20101
The Japanese body for ISO TC 165 can not be accepted on the adoption of ISO/DIS 12583-1/2. The comments and suggestions of Japanese body were described.
K Suzuki


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


Japanese Classification of Wooden Building Members for ISO Use Classes according to the Building Code in Japan.
2006 - IRG/WP 06-20337
Because of the international approve of use class system for the biological degradation of wood by ISO/DIS 21887 and ISO/DIS 21892, Japanese committee of ISO/TC165/SC1 asked to the JWPA for classify the wooden commodities by use class of these draft ISO. The JWPA was prepared a draft use class model in Japan. Japanese building code systems are described and Japanese draft use class system is also described.
K Suzuki


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