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Above ground performance of CCA-treated fingerjointed lumbe
1993 - IRG/WP 93-40003
Studs made from short lengths by finger jointing are becoming more commonly used in North America. Recently Forintek has received enquiries about the performance of such material in a treated form. Treated and untreated nominal 2x4 inch² spruce-pine-fir (SPF) studs exposed above ground for 12 years in southwestern British Columbia were evaluated for evidence of decay. Despite shallow preservative penetration, which did not meet North American standards, the CCA-treated material showed no signs of decay. In contrast two of the 30 untreated samples had failed and the mean rating was 1.3 on a 0 to 4 scale. These results are encouraging for the use of CCA treated SPF as finger jointed or conventional lumber in above ground exposure.
P I Morris, G E Troughton


Risk of extension of Hylotrupes bajulus attack in glued laminated timber
1977 - IRG/WP 278
Although efficient work-methods and maintenance procedures, which prevent the wood from becoming damp and are therefore successful in considerably reducing and even in excluding the risks of decay, such methods are ineffective in eliminating the risks of infestation and destruction of timber by the House Longhorn Beetle, Hylotrupes bajulus, the chief enemy of softwood timber structures. The possible treatment of glue-laminated timber frames has only been systematically studied for the last few years and is generally limited to the surface application of organic solvent type preservatives. In most cases, this treatment is carried out at the factory before final warnishing takes place. The aim of this paper is not to discuss this type of treatment, which would require certain reservations. As many untreated timber frames have been erected and since in the majority of those which are currently being erected, cracks - ideal sites for the House Longhorn Beetle to lay its eggs are discovered chiefly during the first year, its seems pertinent to examine the dangers of increased infestation in this type of structure and the need for eradicant treatment; in other words, to examine wether successive laminates or ultimately the entire beam will be affected if one infested laminate is incorporated into a particular structure or whether infestation will remain confined to the initial laminate. We shall need to determine whether the larvae of Hylotrupes bajulus are capable of penetrating the various types of glued- laminated timber. By gluing together thin layers of wood of limited length, the technique of glued laminates aims at manufacturing wood products which are both thick and of great bearing, but which proportionally have only slightly less mechanical strength than the same piece of solid wood. There are two types of assembly: 1) by gluing together laminates lengthwise, so as to produce beams of given thickness, and 2) by gluing together end-grain surfaces of laminates so as to produce beams of a given length. Both types of assembly are included in the diagrams accompanying this paper. The possible penetration by larvae of the House Longhorn Beetle have been studied in the case of each type of assembly. It is also known that the larvae of this species are capable of penetrating various kinds of relatively hard substances. In this respect, larvae at various stages of development can behave in different ways for tunnelling capacities. Hence the experiments described below have been carried out with two types of larvae: newly hatched larvae and larvae of medium size.
M-M Serment


Progress report on co-operative research project on L-joint testing
1983 - IRG/WP 2192
A F Bravery, D J Dickinson, M Fougerousse


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


Wood preservatives: Field tests out of ground contact. Brief survey of principles and methodology
1976 - IRG/WP 269
This paper contains the following spots: 1.: The general need for field tests. 2.: Interests and limits of field tests in ground contact. 3.: Various methods in use for out-of-ground contact field tests. 4.: Fungal cellar tests are they an alternative to above-ground decay exposure tests? 5.: Conclusions.
M Fougerousse


Co-operative research project on L-joint testing. Sampling after 8 months exposure
1983 - IRG/WP 2208
It was anticipated in Document No IRG/WP/2192 that exposure of L-joints by the European co-operators would take place on 1 April 1983. Where L-joints were exposed at this time, sampling after 8 months exposure is due on 1 December 1983. The present document draws attention to relevant previous documents which describe the sampling methods to be adopted. It also provides Tables for recording the results.
J K Carey, A F Bravery


Gloeophyllum trabeum and Gloeophyllum abietinum, the most frequent brown rot fungi in fir wood joinery
1999 - IRG/WP 99-10319
In Croatia the primary raw material for joinery production is silver fir wood (Abies alba Mill). L-joints made of home-grown fir sapwood and prepared according to EN 330: 1993 were used to establish the infection and colonisation of micro-organisms, particularly wood decay fungi, to compare the performance of untreated and 1% TnBTO treated L-joints. The L-joints were coated with two types of coat, and 36 months exposed in Zagreb. The first type of coat was alkyd paint and the second was a stain, in three different colours: white, brown, and black. The influence of the preservative, and the type of coat were most important factors which affected the rate of colonisation. The influence of coat colours was significant at the the beginning of exposure. The fastest and the strongest colonisation occurred in untreated L-joints coated with alkyd paint and the lowest colonisation occurred in treated L-joints coated with stain. It was due to the well known vaporous diffusivity of the stains and the low natural permeability of fir sapwood. The most frequently isolated fungi were Gloeophyllum trabeum (Pers.: Fr.) Murr. and Gloeophyllum abietinum (Bull.: Fr.) Karst.
R Despot, M Glavas


Short-term field test method with accelerated infection of Basidiomycetes in wood
1981 - IRG/WP 2155
In the ŠIPAD - IRC Wood Protection Laboratory an attempt has been made to develop a simple short-term method for field testing out-of-ground contact wood using accelerated infections with Basidiomycetes. This method makes it possible to obtain a preliminary assessment of a preservative's quality and to estimate the possibility of achieving promising results in more expensive long-term tests. The idea was to use water traps (reservoirs) and 50 x 25 x 15 mm³ laboratory infected pine blocks as the substrate to improve the possibility of inoculation of L-joints.
N Vidovic


An approach to testing the preventive effectiveness of preservative treatments for wooden joinery
1981 - IRG/WP 2156
The ecological sequence established in field trial samples exposed out of ground contact has shown the need for outdoor exposure in testing potential joinery preservative pretreatments. A system of exposure of L-joint units is proposed. Data obtained by examining samples destructively show promise as the basis for predicting service life after relatively short exposure periods (within 2 years).
J K Carey, A F Bravery, J G Savory


Surface coatings for impregnated wood
1992 - IRG/WP 92-3684
The use of proper surface coatings enhances the aesthetic and protective properties of impregnated wood. Good results with especially water-borne coatings have been obtained for class-A impregnated L-joints and claddings in field tests started in 1982.
L Kotama


Translation of CEN Letter to Mr R Cockcroft dated 24 November 1980
1980 - IRG/WP 2147
G Castan


Field trials on preserved timber out of ground contact
1978 - IRG/WP 3154
This report describes two different field trials studying the performance of preservative treatments on timber exposed to the weather, but above the ground. Results are presented on the protection afforded against decay, and on the efficiency of water-repellent preservative treatments in controlling the uptake of moisture by the timber. Proposals for a standard field test system are briefly discussed.
D F Purslow, N A Williams


Performance of surface-treated hardwoods and softwoods out of ground contact
1990 - IRG/WP 3592
A number of fungicides were tested as brush treatments for protection of southern pine, Douglas-fir, maple, and red oak against decay above ground. Cross-brace and L-joint test units were treated just before assembly and exposed from 3-10 years. Untreated Douglas-fir cross-brace units were not decayed at either the Mississippi or Madison, WI, site. Untreated red oak cross-brace units were not decayed at the Madison site. The two hardwood species were more difficult to protect from decay than the softwood species. Decay development in maple cross-brace units was considerably slowed by several of the treatments but none of the treatments provided complete protection from decay during the 9 or 10 years exposure in Mississippi. Most of the treatments did not reduce decay development in red oak cross-brace units. Many treatments protected pine cross-brace units. The L-joints were exposed for only 3-4 years, but appear more difficult to protect from decay than the cross-brace units.
T L Highley


Co-operative research project on L-joint testing. Progress report to March 1988
1988 - IRG/WP 2315
Further sets of data received from CTFT (France), BAM (Germany) and PRL (UK) after 46-48 months exposure and STU (Sweden) after 22 months exposure are presented and discussed in conjunction with data reported previously. Colonisation and attack of the L-joints has progressed with increasing exposure period. The new data are generally in agreement with those presented previously and the major difference between Institutes continues to be one of rate of colonisation rather than any relative difference in performance of the treatments. Overall 0.5% TnBTO 1 min dip treatment is providing least protection followed by 1.0% TnBTO 1 min dip treatment. The double vacuum treatments continue to provide better protection than the dip treatments; there are now indications that 0.5% TnBTO double vacuum treatment is less effective than 1.0% TnBTO.
J K Carey, A F Bravery


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


Report of field test results for dichloro-n-octyl-isothiazolone: A potential new wood preservative
1988 - IRG/WP 3495
In a previous report (IRG/WP/3306) we presented preliminary laboratory test results on 4,5-dichloro-2-n-octyl-4-isothiazolone (RH 287). Laboratory data indicated toxic threshold values for RH 287 ranging from 0.37 to 0.50 kg/m³. In this report we present field test results on an IRG L-joint test and an in-ground stake test for RH 287, pentachlorophenol and biocide free test units. (a) L-joint test: After 39 months exposure (Starkville MS.) units pressure treated with 0.05 kg/m³ RH 287 rated 9.7 out of 10. Units dip treated in a 0.5% ai solution of RH 287 rated 10 out of 10. Biocide free controls exposed in the same series rated 5.3 out of 10 after 39 months (b) Stake test: After 48 months exposure in two southern US test plots stakes treated with neat RH 287 in toluene at 4.6 kg/m³ rated between 8.6 to 8.8 out of 10 for decay and 9.1 to 9.8 out of 10 for termite attack. Biocide free control stakes rated O out of 10 for decay and 1.1 to 4.8 out of 10 for termite attack after 48 months. RH 287 continues to show promise as a potential new wood preservative. Results to date were obtained in samples treated with neat RH 287, Formulation of RH 287 into treatment systems specifically designed for above ground or ground contact applications should only improve the already excellent activity seen with RH 287.
D E Greenley, B M Hegarty


Germination of basidiospores on preservative treated wood after leaching or natural weathering
1981 - IRG/WP 2150
In tests of residual toxic efficacy after leaching or natural weathering, spore germination with Gloeophyllum trabeum has proved to be a less reliable criterion of attack than when used with unaged preservative treatments. Since spores sometimes prove more tolerant than their parent mycelium, their use should be continued.
J K Carey


Climate indices at work: Above ground decay L-joint tests (EN 330 and AWPA E9) at two sites 12000 km apart and with Scheffer climate indices of 60-65 and 300-330
1996 - IRG/WP 96-20095
Matched sets of Scots pine sapwood (Pinus sylvestris) L-joints were exposed above ground at two field sites for approximately five years. One site, at Garston, Watford, UK has a climate index between 60 and 65 while the other, close to Hilo, HI, USA has an index between 300 and 330. The joints were treated with a range of organic solvent treatments applied either by three minute dip immersion or by double vacuum. Untreated joints were installed at each site as control material. All samples were assessed at approximately annual intervals at both sites. After five years, decay at the Hilo site is well advanced with failure apparent in many joints, both untreated and treated. As would be expected given the climatic differences, decay at the Garston site has progressed more slowly than in Hilo. Differentiation in treatment performance was apparent after one year's exposure in Hilo with similar differentiation becoming apparent after five years' exposure in Garston. This acceleration correlates well with the difference in Climate Index for the two sites as calculated using the Scheffer method. Encouragingly, the performance ranking of the different treatments at the two sites was very similar. The results of this test suggest that the concept of using high decay hazard sites for field testing of treated wood products for use in above ground situations can provide meaningful results in a short period, and may offer a timely and realistic alternative to relative preservative testing to that achieved in laboratory test regimes. The results also show that above ground field testing at both of the sites included provide valuable information on preservative performance, and this information is likely to provide a greater degree of realism than is possible using pure culture laboratory test procedures.
A F Preston, K J Archer, D M Roberts, J K Carey, A F Bravery


Chemical analysis of TnBTO in lap-joints
1999 - IRG/WP 99-20173
This research was performed as part of the EU project FACT (contract SMT4-CT96-2135) on field tests out of ground contact and ageing methods. The results reported here are part of the work on the experimental lap-joint standard (ENV 12037). TNO investigated the TBTO content of 32 lap-joints by analysing the tin content of 90 samples. The lap-joints were treated with two different TBTO-concentrations (0.5%; 1.0%) and different treatment methods (brushing, dipping, vac-vac treatment). Analysis took place after initial treatment and 6 months after field testing above ground at the test site at Delft, The Netherlands. The samples for analysis were taken from the top layer (first 3 mm) and from the inner part of the lap-joint. Preliminary tests with different extraction methods (AWPA, CTBA and DPI-FS) for tin analysis in wood showed the highest recovery rates for the AWPA method. Therefore extraction of the wood samples was carried out in accordance to the AWPA-A6-89-4 method. The extracts were analysed by ICP-AES. Results of the tin analysis are discussed referring to theoretical TBTO concentration, treatment method and sample origin.
A Voss, P Esser, W L D Suitela


Co-operative research project on L-joint testing. Progress report to May 1989
1989 - IRG/WP 2338
Further sets of data received from STU (Sweden) after 36 months exposure and Sipad-IRC (Yugoslavia) after 45 months exposure are presented and discussed in conjunction with data reported previously. The new data are generally in agreement with those presented previously and the major difference between institutes continues to be one of rate of colonisation rather than any relative difference in performance of the treatments. Some data from the co-operating institutes is still outstanding. A final report summerising the whole trial will now be produced.
J K Carey, A F Bravery


Leaching results of shower test on L-joints with boric acid, bifluoride and TBTO rods
1995 - IRG/WP 95-50051
As part of the EC-project "Improvement of a local preservation process for wood products with reduced environmental impact", TNO has performed a leaching test on L-joints treated with pills with boric acid (Defence corner), bifluorides (Woodpil 55) and TBTO (Woodcap). The L-joints were exposed in an adapted shower test during 10 days, using 70 liters of water per day. The experiment is designed to measure leaching under extreme service conditions. Spruce and pine, painted and unpainted L-joints were compared. In general leaching was the highest in spruce. The L-joints treated with boric acid pills showed the highest leaching, with very small differences between painted and unpainted L-joints. Leaching from fluoride and TBTO treated L-joints was even slightly higher than in painted L-joints. From these results it is suggested, that the active ingredients predominantly leach from the end grains in the open joint area of the timber. A higher water run off rate from longitudinal surfaces in painted L-joints could explain for the higher leaching rate in these samples
P Esser, M J Boonstra, W L D Suitela, A J Pendlebury


Co-operative research project on L-joint testing. Progress report to March 1984
1984 - IRG/WP 2211
Each participant was intended to expose L-joints in the main trial on 1 April 1983 and the first sampling, after 8 months exposure, was to be undertaken on 1 December 1983. Some participants have had to vary this schedule. Results are presented from CTFT (France) and PRL (United Kingdom). These show a greater effectiveness by the double vacuum treatments compared with the 1 minute dip treatments. However, results from the two locations differ particularly in the incidence and type of Basidiomycetes isolated.
J K Carey, A F Bravery


Recent developments in the treatment of sawn spruce by double vacuum impregnation
1978 - IRG/WP 3114
The timbers used for building purposes in the U.K. and on the Continent of Europe are mainly softwoods. The two types of wood most used are redwood (Pinus sylvestris) and whitewood (Picea abies or Picea sitchensis). Other species are used to a lesser extent when considerations such as a long length requirement or width requirement demand the use of, for example, hemlock, Douglas fir or Parana pine. Traditionally redwood has been favoured in the U.K. for use as external joinery timber where the decay risk is high, and to date it is still used very extensively for this purpose. Whitewood on the other hand is used for carcassing and internal work. This pattern of usage is not reflected on the Continent and the rest of the world. This traditional situation may not continue to be with us indefinitely. In 1973, supply difficulties forced some U.K. external joinery manufacturers to use whitewood, and current timber production trends make a recurrence of this situation a likely probability. Already spruce is being used in laminated beams for swimming pool roofing and in flat roofs. In both situationa there is a high risk of fungal decay. It is with a view to this wider utilisation of whitewood that this paper is presented as a 'state-of-the-art' report.
C T Kyte, L D A Saunders


Above-ground field tests undertaken in New Zealand
1995 - IRG/WP 95-20063
In addition to "standard" L-joints, above-ground test material exposed at the NZ FRI test site includes treated and untreated decking units, Y-joints, fence battens and weatherboards either with or without additional protection from surface coatings. The latter tests bridge the gap between "model" test assemblies, such as L-joints, and services tests. Most tests are of preservative-treated radiata pine using proprietary formulations which were approved for above ground use at the time when each test was established. Other tests are natural durability tests to determine the suitability of those species, in terms of durability and mechanical properties, for above ground use without preservative treatment. The first tests were established in 1952 and results from those and subsequent tests have been used during periodic amendments to NZ wood preservation standards and specifications. The purpose of the different tests is described as well as pertinent results from them to illustrate their value.
M E Hedley, D R Page, J B Foster, B E Patterson


BRE Experience in monitoring decay in out-of-ground exposure trials
1995 - IRG/WP 95-20077
The outdoor field trial has always been regarded as the ultimate test of performance for assessing the effectiveness of a wood preservative. For this reason, the Building Research Establishment (BRE) has invested much effort in such trials over many years. Emphasis in early trials was on ground contact tests which were the basis both for assessing the likely performance of a preservative in protecting posts and poles, and for classifying a timber's natural resistance to fungal decay. When preservation of timber in the building and construction industry assumed greater importance, the emphasis was placed on the development of out-of-ground field trials to provide data on the likely performance of exterior joinery work in buildings. For these tests, the exposure conditions provided a less severe hazard for out-of-ground timber than for wood permanently in contact with the ground. Out-of-ground trials have been running at BRE since 1967 (Orsler and Smith, 1993) initially using T-joints and L-joints and later the window joinery test rig was established to provide conditions close to those in buildings (Purslow, 1975). All the early trials were assessed only by visual assessment for decay. Later still, small L-joints with a coating (the methodology which was used as the basis for EN 330) were used for a comprehensive study to establish the pattern of colonisation by microorganisms and associated changes to the wood. It was established that the basidiomycete fungi ultimately responsible for the decay are the climax of a colonisation sequence of a range of types of fungi plus bacteria (Carey, 1980). In an attempt to give early indications of long term performance, colonisation by basidiomycetes and changes in the porosity of the wood during exposure have been used as the basis for assessing performance relative to that of a reference preservative (1.0% tri n-butyltin oxide). Hyphen joints were introduced (Orsler and Holland, 1993) for studies of preservative distribution.
J K Carey, R J Orsler


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