Your search resulted in 86 documents. Displaying 25 entries per page.
Field tests out of ground contact in France: Definition of the test procedure and preliminary results after 18 months
1981 - IRG/WP 2161
Studies of the distribution and degradation of tributyltin naphthenate in double-vacuum treated wood
1983 - IRG/WP 3230
The effects of forced solvent evaporation by kilning redwood (Pinus sylvestris) that has been double-vacuum treated with tributyltin naphthenate (TBTN) have been investigated. Contrary to previous studies reported, it has been shown that forced evaporation can have a considerable influence on the losses of the fungicide. It has been found that, whether the solvent is allowed to evaporate slowly or the evaporation is forced by kilning, the TBTN breaks down considerably in freshly treated wood. In view of the implications of this work for the long-term effectiveness of TBTN further studies are called for.
J Jermer, M-L Edlund, W Hintze, S V Ohlsson
Analysis of organotin fungicides in wood preservative solutions and double-vacuum treated wood
1983 - IRG/WP 3250
A new analytical method using high-performance thin-layer chromatography (HPTLC), for the assay of organotin compounds in preservative-treated wood, is presented. The organotin compounds are extracted from the ground wood sample with a mixture of hydrochloric acid and ethanol. After HPTLC-separation, exposure of the thin-layer plate to ultraviolet light, and dipping of the plate into a 0.1% pyrocatechol-violet solution, the different organotin compounds are quantitated using a scanning densitometer.
W Hintze, S V Ohlsson
Treatment of messmate (Eucalyptus obliqua L'Hérit) by double-diffusion: Preliminary report
1983 - IRG/WP 3234
Modified double-diffusion is suggested as a method of impregnation for mixed tropical hardwoods for certain types of ground contact use in less developed countries. Compared with vacuum/pressure impregnation, capital costs are low and little skill is needed for the operations involved. Treatment of messmate (Eucalyptus obliqua L'Herit) rounds involving pre-heating in water prior to their immersion in the first stage solutions is described. Preliminary indications are that (i) there is a deeper penetration of arsenic when a compound of this element is used in the first stage solution (ii) a more even and deeper penetration of chromium is obtained when sodium chromate, rather than sodium dichromate, is used in the second stage solution. It is concluded that quality control in double-diffusion may be a limiting factor in the adoption of the process for the treatment of wood unless a simple but effective method is found to control solution concentrations and elemental ratios.
F F K Ampong, C-W Chin
Effect of double-vacuum and vacuum-pressure impregnation with water-borne preservatives on the dimensional characteristics of spruce
1990 - IRG/WP 3613
Air-dried planed spruce (Picea abies) samples were treated with a water-borne preservative (micro-emulsion) and one oil-borne type both containing azaconazole and deltamethrin. Each set of samples contained equal number of specimens with different growth ring orientation, heartwood content and density. In addition to the preservative retention and the penetration of a.i., the swelling of the samples was measured immediately after impregnation and further after 6, 24 and 48 hours. The growth ring figure induced different uptake levels when the impregnation process was intensified. Gradual increase of tangential surfaces reduced the retention. The effect of the wood properties on liquid absorption seemed to be greater for the oil-borne treatment. Volumetric swelling of the test samples treated with the water-borne solutions ranged from 0,5 to 0,6% immediately after double-vacuum impregnation increasing to a maximum of 0,8% 6 hours later. Subsequent air-drying of treated samples did not produce checking nor deformation. The oil-borne preservative gave rise to a swelling 3 to 4 times less. A swelling of 0,8% for spruce treated with a water-borne preservative may be considered acceptable taking into consideration volumetric movement figures of 1 to 1,5% for tropical hardwood species, classified as low movement timbers.
J Van Acker, M Stevens, G Rustenburg
TBTO absorption and penetration in pine joinery treated by various processes
1989 - IRG/WP 3523
Matched sections of several White pine (Pinus strobus) and Ponderosa pine (Pinus ponderosa) mouldings were treated with TBTO by Double vacuum, modified empty-cell, 15 second dip and several preheating treatments followed by a 15 s dip treatments. As expected the double vacuum and empty-cell (batch) treatments resulted in much greater retentions and penetrations than the dip treatments. The absorptions by the 15 s dip treatments could be improved significantly by preheating the wood to 60-90C° by microwave, radio-frequency or infra-red techniques. Since this approach is amenable to a continuous treatment process, it is being evaluated for potential commercial application.
P A Cooper, Y T Ung
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
The treatment of sawn whitewood with organic solvent wood preservative
1982 - IRG/WP 3192
The impregnation schedules approved in the UK for the treatment of sawn European whitewood (Picea abies) with organic solvent borne preservatives result in comparitively high loadings relative to the limited depth of penetration they achieve. Results are presented, which show how substantial reduction in the overall loading may be achieved without concomitant reduction in penetration. A model for organic solvent behaviour is postulated as a basis to account for these findings.
L D A Saunders
Preservative treatments of window components with a water-based borate formulation
2000 - IRG/WP 00-40171
Factory finished window joinery components were treated with an aqueous borate preservative in order to investigate penetration and retention levels, associated drying times; and the potential impact of using a water-based treatment on finished items. It was found that by using borates applied by light double vacuum schedules, it was possible to meet standards for penetration and retention, to air dry components within 48 hours; and to avoid other potentially significant negative impact usually associated with aqueous treatments. It is also suggested that current penetration requirements are inappropriate for mobile preservatives. This initial study indicates that it is possible to replace organic solvent carried preservatives with water-borne technology. The potential impact within Europe is of significance as most authorities have introduced mandatory requirements to move from solvent to aqueous systems where it is shown possible to do so. These treatments have now been adopted commercially by some treaters in the UK and are being considered by window manufacturers in Germany and Sweden.
J Jermer, J D Lloyd
Collaborative field trial out-of-ground contact
1982 - IRG/WP 2179
At the 12th meeting of the IRG in Sarajevo, Yugoslavia it was decided after considerable discussion that the best way to proceed with the work of the subgroup was to centre it around a co-operative field trial based on the L-joint test detailed in IRG/WP/2157. At the same time it was agreed that interested laboratories would also conduct their own methods, particularly the German planner test and the French and Yugoslavian inoculation techniques. It has since been decided to concentrate the main part of the test within Europe using Pinus sylvestris joints from a common source and to provide chemicals to other laboratories interested in conducting a similar trial with their own wood species. In this way it is hoped to achieve a tightly controlled comparative test with the CEN countries and to allow greater international comparison. The test is to employ simulated joinery units treated with a good and poor preservative system and exposed out of doors. Periodically replicates will be examined destructively. The destructive examination will consist of a measure of the onset of increased permeability of the wood and the initiation of colonisation by wood destroying Basidiomycetes. It is proposed to use two levels of TnBTO in a model preservative and to apply the preservatives by dipping and by double vacuum.
D J Dickinson, A F Bravery, J K Carey
Sawn timber of fir (Abies alba Mill.) - Treatability and usability for the Hazard Classes 3 and 4
1999 - IRG/WP 99-40147
Within a national research project, tests on the treatability on sawn timber of fir (Abies alba Mill.) in oscillation pressure, vacuum pressure and double-vacuum processes have been worked out with 95 trunks taken from 3 different altitude levels (up to a height of 590 metres, 600 to 990 metres and over 1000 metres) and from 4 different regions of Switzerland. As the treatability of round wood can be compared with that of spruce (Picea abies L.), the sawn timber shows a considerably higher retention and penetration of the preservative. According to the standard EN 350.2 this wood can be classified into treatability class 2. With a vacuum pressure process a much better quality can be reached than with an oscillation pressure treatment. The treatability can be influenced by the origin of growth, as far as wet heart appears increasingly on a fir location; lumber with wet heart has a four times higher retention. The altitude of growth had no significant influence on the impregnation quality. The good retention and penetration of the preservative makes these wood species suitable for weather exposed outside constructions of solid wood or glued laminated timbers (for example bridges, acoustic and face protection walls, fences and toys). As the heartwood of fir is impregnated too, an adequate or even longer durability than with Scots pine (Pinus ssp.).can be obtained for treated construction wood.
E Graf, T Bör
Chemical and biological investigations of double-vacuum treated windows after 5 years in service
1983 - IRG/WP 3219
In 1980 The Swedish Wood Preservation Institute initiated an investigation to study the degradation of TBTO and possible fungal attack in double-vacuum treated window joinery in service during 5 years. A hospital in Gothenburg was chosen that was built during 1969 to 1976. Both untreated and double-vacuum treated windows of Pinus sylvestris were used. A brown alkyl oil type paint (Nordsjö system Rubbol S) was used for the surface coating. The double-vacuum treatment was carried out with Vascol EWR 52A according to a specification that in 1977 became preservation class B, Swedish Standard SIS 05 61 10, viz. at least 10 mm penetration of the sapwood and a retention of approximately 50 kg/m³ sapwood (approx. 0.1% m/m TBTO). In April 1981 approximately 200 windows, treated and untreated, were inspected. From 12 treated windows, then about 6 years old and exposed to weathering for 4.5 to 5.5 years, samples were taken for chemical and biological analyses, the objective being to find out to what extent the TBTO had been degraded but also to get an idea what species of micro-organisms had invaded the wood and if the protection against decay was still sufficient.
J Jermer, M-L Edlund, B Henningsson, W Hintze, S V Ohlsson
Chemical and biological investigations of double-vacuum treated windows after 7½ years in service
1985 - IRG/WP 3339
Earlier investigations of double-vacuum treated windows after five years in service have shown that tributyltin oxide (TBTO) degrades to di- and monobutyltin compounds and that the resistance of the wood against decay decreases. An investigation 2.5 years later of the same windows shows that the degradation of TBTO proceeds fast. After 7.5 years in service only 15-35% of the remaining organotin compounds consisted of TBTO. A clear correlation between the percentage of TBTO in the wood and decay resistance of the wood was found.
M-L Edlund, J Jermer, B Henningsson, W Hintze
Manual of a mini treating plant for waterborne preservative treatment of timber and bamboo
1999 - IRG/WP 99-40130
This contributional article includes machinaries and equipments necessary for a small wood treating plant for the pressure treatment of tim bers with waterborne preservatives along with the cost and design. The preservative treatment limitations, treatment schedules and specifications for different products have been described. The cost of a mini treating plant will be 6,00,000 Tk. (13,000 US$), suitable for preserving timber and bamboo products for indoor and outdoor uses and will out last teak wood. The additional durability of timber and bamboo will create economically and environmentally safe conditions.
A K Lahiry
Performance of treated fence posts after 6 years in five test plots in the State of Sao Paulo - Brazil
1976 - IRG/WP 376
Fence posts treated with creosote, pentachlorophenol and creosote/ pentachlorophenol mixtures showed good performance after 6 years of exposure in five test plots located in the State of Sao Paulo - Brazil. Good results were also achieved with copper sulphate/sodium arsenate and copper sulphate/potassium dichromate mixtures. Fungi and termites were the main destroying agents found attacking the posts.
M S Cavalcante
Effects of various preservative treatments on the mechanical and physical properties of plywood
1993 - IRG/WP 93-40007
The technical properties of plywood are related to both the intrinsic characteristics of its composing wood species and the quality and performance of the glue bond which acts as an interface between veneer sheets. Consequently mechanical and physical testing and glue bond strength analysis offer an appropriate means for studying the effect of preservative treatments on the overall quality of plywood. A range of boards was treated with waterborne and oilborne preservatives. Changes in modulus of elasticity, modulus of rupture and tensile strength were noted as well as variations in physical properties. Analysis of the glue bond strength was done by shear strength testing and determination of the amount of wood failure after different ageing procedures.
J Van Acker, M Stevens
Preservative treatment of Eucalyptus saligna fence posts by the double-diffusion method
1982 - IRG/WP 3196
Eucalyptus saligna fence posts treated by the double-diffusion method with two chemical combinations showed average lives of 11.2 years (copper sulphate and potassium dichromate at 10.5 kg/m³ retention)and of 14.3 years (copper sulphate and sodium mono-H arsenate at 7.1 kg/m³ retention), as determined in five test sites in the State of Sao Paulo, Brazil. The exponential model was the best fit when expressing average life by the Decay Index (DI) as a function of time.
E S Lepage, A R De Freitas
An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper-chrome-arsenic preservative
1981 - IRG/WP 3150
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. We have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins
Report on the treated piles and fenders in the wharves in Port Moresby harbour, and the Huon Gulf, Lae
1977 - IRG/WP 433
To investigate the resistance of Papua New Guinea timber, vacuum pressure impregnated with Copper-Chrome-Arsenic salts, to marine borer attack in the waters of Papua New Guinea.
S M Rayner, C R Levy
Report of the meetings of the Refractory Timbers Sub-group, Rotorua, New Zealand, 15 & 17 May 1990
1990 - IRG/WP 3637
R J Murphy
Collaborative soft rot tests: Summary of comments on 'Proposals for a standardized soil burial test'
1971 - IRG/WP 202
J G Savory
Technique for monitoring absorption during a vacuum pressure process
1992 - IRG/WP 92-3696
A laboratory technique was developed and an apparatus constructed which allowed for the direct and continuous measurement and observation of volumetric uptake of water-borne preservative into wood samples throughout a controlled vacuum-pressure treatment process. Fractional filling of void space was calculated. Graphing (fractional saturation) against time allows prediction of optimum cycle lengths with respect to achievable saturation values. Treatability evaluations using this technique were carried out on heartwood samples of six Malaysian hardwood species, kapur, kempas, keruing, punah, rubberwood, simpoh and on sapwood samples of Scots pine as a control. Generally the graphs exhibited two quasi-linear zones showing rapid initial absorption followed by slow absorption over a long period.
A J Pendlebury, J A Petty
A comparison of the effectiveness of a vacuum oven and a wind tunnel in the accelerated ageing of treated wood by evaporation
1989 - IRG/WP 2334
R J Orsler, G E Holland
Collaborative soft rot tests: Proposed amendments to Document No: IRG/WP/208
1973 - IRG/WP 224
J K Carey, J G Savory
Developments in wood preservation processing techniques in New Zealand
1980 - IRG/WP 3143
P Vinden, A J McQuire