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Controlling marine borer attack of timber piles with plastic wraps
1981 - IRG/WP 479
Plastic films 20 to 40 mils thick have been used for many years to wrap creosoted timber piles in service to protect them from attack by marine borers. As long as the wrap remains undamaged, this procedure provides complete protection to the pile. Properly applied, wraps generally provide protection for 25 yeara or longer. Polyvinyl chloride (PVC) and polyethylene (PE) films are specially formulated for long service, especially in the intertidal zone where they are exposed to sunlight, wave action and abrasion. Carbon black and other inhbitors are used to prevent degradation from the sun's actinic radiation and embrittlement. The Port of Los Angeles requires a minimum carbon black content, film weight basis, of 1.5% for PVC and 2% for PE. The films differ in handling characteristics in water. PVC is tougher and more flexible than PE but tends to sink whereas PE lends to float. Initially PE is less flexible than PVC but, with time, PVC can lose its plasticizers becoming harder and more brittle than PE. PVC wraps have been in service about 25 years and PE wraps for 5 years with only scattered reports of polads (Martesia) penetrating PVC in Hong Kong, Panama and Brazil. The extent of attack appears slight. Films 10 mils or less in thickness can be damaged by crabs and other marine animals capable of grasping and tearing the film. Usually a diver wraps the film around and fastens it to a pile in place. A diver and a support crew of one or two persons wrap up to 250 linear feet of piles per day at a labor cost of over $900. Depending on diving conditions, the labor cost for wrapping piles ranges from $4.50 to $10.00 per linear foot of pile.
F Steiger, G Horeczko


Information from the COIPM Wood Group
1988 - IRG/WP 4146
Abstract from the COIPM minutes: Wood in marine environment: Mrs Gambetta stated that the main item discussed by the Group was the collaborative work to test the durability of heat shrinkable polyolephin sheating materials for the protection of wood against marine organisms. The work began last year when wood samples were sent out to the participants. Three samples of Pinus sylvestris wrapped in polyolephin supplied by Raychem were sent to the following participants: Mr. RASMUSSEN who put three stations at the disposal of the group: one in Denmark, one in Spain and one in India; Prof. RELINI with two stations: Rapallo and Loano in the Gulf of Genoa; Prof. GARETH JONES: Langstone station in England; Dr. GUEZENNEC: Tahiti Station; Dr. GAMBETTA and Dr. ORLANDI: Follonica station (Tyrrhenian Sea). The information regarding the physical and chemical characteristics of the stations as well as the most damaging marine organisms has been recived. The inspections regarding good or poor condition of samples have not yet been made but those in charge of the test would send the results as soon as possible. Dr. HABAL is also going to take part in the work and the samples would be sent out to him for exposure at his station. There was a second part in the collaborative programme: a study on the resistance to marine organisms of pressure treated wood with polymers. The tests with styrene are being undertaken. Preliminary tests were made at Follonica station but the bad results achieved prevented the group from extending the trials to other stations. The second item dealt with was the IRG/COIPM cooperative programmes. The first one regards different species of wood treated with CCA and CCB (Pinus, Alstonia, Fagus). The work already started nine years ago. Now it can be said that the two saline products gave results somewhat similar and chemical analyses have shown that Boron and Arsenic had a strong leaching therefore seems that a better protection is ensured by copper and chromium. The second one aims at studying the efficacy of polyurethane coatings on wood samples against marine organisms. The group also discussed the work in progress in the various member laboratories. Dr. HABAL informed on his tests on the behaviour of wood samples treated with TBTO and TBTF and also on the incorporation of antifouling materials into elastic paint like commercial preparation that can be applied as a thick layer onto wood pilings. He was also participating in the heat shrinkable plastic cooperative programme. Mr. DE PALMA was continuing his tests on polyolephin sheatings at his two stations and at other stations: Italy, Spain, India (stations of Follonica and Cadiz). He was also taking part in the IRG/COIPM collaborative programmes. Dr. GAMBETTA reported her tests carried out at Follonica on wood treated with organotins which were exposed in the marine environment during twelve years. She was also taking part in the IRG/COIPM cooperative programmes.
A Gambetta


Plastic-coated marine piling in Los Angeles Harbour
1984 - IRG/WP 4105
G Horeczko


Proposal for further work on accelerated ageing
1988 - IRG/WP 2314
M-L Edlund


Summary of development of pile wrappings in Los Angeles Harbour
1987 - IRG/WP 4141
G Horeczko


Thermal treatment of wood: European Processes and their background
2002 - IRG/WP 02-40241
Recent efforts on thermal treatment of wood lead to the development of several processes introduced to the European market during the last few years. The total production capacity of heat treated wood in 2001 is estimated as approx. 165.000 m3. In the paper the different heat processes are presented. The general technology as well as scientific data on the chemical transformation of the cell wall polymers, on the biological performance, on the physical and mechanical properties of the treated wood are presented and discussed
H Militz


Durability of pine modified by 9 different methods
2004 - IRG/WP 04-40288
The decay resistance was studied for pine modified by nine methods of wood modification: 1) Acetylation, 2) Treatment with methylated melamine resin (MMF), 3) Acetylation followed by post-treatment with MMF-resin, 4) Thermal modification, 5) Furfurylation, 6) Maleoylation (using water solution of MG or ethanol solution of maleic anhydride), 7) Succinylation, 8) NMA-modification and 9) modification with reactive linseed oil derivative (UZA), Wood blocks of Scots pine (Pinus sylvestris L.) sapwood were modified in pilot plants. Methods 1-5 were performed by the authors at Chalmers University of Technology or at BFH in Hamburg. Methods 5-9 were part of a European research project (the Chemowood project, FAIR-CT97-3187) and therefore each of these modifications was performed by the project participant responsible for the method. For laboratory testing in TMCs (modified European standard ENV 807) and pure basidiomycete culture bioassays, smaller test specimens were cut from the modified wood blocks. Most of the modification methods were applied on test specimens for marine field testing (EN 275) and some methods to produce mini-stakes for field tests in five Swedish fields. Some modification methods result in modified wood with poor durability, whereas other methods (acetylation, furfurylation and MMF-treatment) seem to provide excellent resistance to microbial decay.
M Westin, A O Rapp, T Nilsson


Corrosion of fasteners in heat-treated wood – progress report after two years’ exposure outdoors
2005 - IRG/WP 05-40296
The corrosion of common fastener materials now in use - mild steel, zinc-coated steel, aluminium and Sanbond Z-coated steel – has been evaluated after two years’ exposure outdoors in untreated and heat-treated spruce (Picea abies) respectively. Spruce from South-western Sweden was used. The heat-treatment was carried out in Finland according to the ThermoWood process at a maximum temperature of 220 °C for five hours. The results so far show that the corrosion of fasteners in heat-treated wood according to the particular specification is more severe than in untreated wood. Mild steel and zinc-coated steel has been most susceptible. Stainless steel is hardly attacked at all.
J Jermer, B-L Andersson


Accelerated ageing of preservatives in treated wood
1988 - IRG/WP 3476
New preservatives are tested in the laboratory and often in field tests before they are used commercially. Some preservatives, however, tested in the laboratory do not show the expected stability when used in service. The differences between laboratory tests and practical use can never be completely eliminated but must be minimized as far as possible by relevant testing methods. Studies of the effect of different accelerated ageing procedures on the chemical degradation and the wood preserving capacity of six different fungicides or combinations thereof have been carried out. Chemicals tested were tributyltinoxide (TBTO), tributyltin naphthenate (TBTN), furmecyclox, benzalkoniumchloride (AAC) + guazatin and pentachlorophenol. The ageing procedures included exposure of test specimens in a wind tunnel (according to EN 73), in an oven at 40°C, 60°C and 70°C, leaching (according to EN 84) and combinations of these procedures. The influence of the different accelerated ageing procedures on the chemical degradation and toxic effect of different fungicides was obvious and, for some procedures and chemicals, comparable with experiences from practice.
M-L Edlund, B Henningsson, B Jensen, C-E Sundman


A collaborative test to determine the efficacy of polyurethane coatings on wood samples exposed in the marine environment
1984 - IRG/WP 4113
Aims are: a) to determine the effectiveness of elastomeric polyurethane as a protective coating against marine wood boring animals in a range of tropical and tempreate sites; b) to compare the adhesion of polyurthane coatings on different wood species exposed in seawater; c) to record the severity of attack in failed samples and to identify the causal marine organisms.
R A Eaton


Information from COIPM Wood Group
1985 - IRG/WP 4120
During the last COIPM Meeting (which took place in Athens, Greece in September 1984) the Wood Group met and discussed the co-operative work 'Durability in sea-water of wood with plastic wraps and wood treated with polymere'.
A Gambetta


Evaluation of wood treated with copper-based preservatives for Cu loss during exposure to heat and copper-tolerant Bacillus licheniformis
1999 - IRG/WP 99-20155
Copper-based wood preservatives need to be effective against exposure to all types of microorganisms. Wood treated with six copper-based preservatives was exposed to 121°C and 20 psi pressure for 15 minutes under standard autoclave conditions and the copper-tolerant bacterium, Bacillus licheniformis CC01, for 10 d at 28°C and 150 rpm. Sixteen to 37 percent of the copper was released from the wood during autoclaving, with copper citrate demonstrating the highest percent loss. Forty-four to 82 percent of the copper remaining in the samples following autoclaving was removed during exposure to the bacterium in liquid culture; copper naphthenate in oil and ACQ-D had losses of eighty percent or greater of the remaining copper. The bacterium removed as much or more total copper in 4 of 6 gas-sterilized samples (85-94%) than the cumulative effects of steam-sterilization and the bacterium on treated samples. Copper loss from in-service treated wood compromises the efficacy of copper-based wood preservatives.
D M Crawford, C A Clausen


Improved resistance of Scots pine and Spruce by application of an oil-heat treatment
2000 - IRG/WP 00-40162
Spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) were subject to a heat treatment which was carried out in an oil-bath. The aim was to improve the dimensional stability of the treated wood and its resistance against fungi. The bath of vegetable oil provides a uniform heat transfer at temperatures of 180°C, 200°C and 220°C and protects the submersed wood from oxygen. Heat treatment in air atmosphere was also carried out at the same temperatures for comparison. Wood treated in hot oil was more equal in its appearance than wood heated in hot air. The treatment of spruce and pine in the oil-bath resulted in a better resistance against Coniophora puteana in a lab test according to EN 113 compared to the treatment in air atmosphere. In order to achieve the wanted upgrading effect, certain changes of mechanical properties and colour must be accepted. However, the strength loss caused by the heat-treatment in oil was less severe than in air atmosphere. Since all materials and the energy used in the process originate from renewable resources, the oil-heat-treatment appears to be environmentally friendly. All in all, the heat treatment in oil might be a promising approach to upgrade wood for outdoor use.
M Sailer, A O Rapp, H Leithoff


Heat treatment of bamboo
2001 - IRG/WP 01-40216
Bamboo is a fast growing material with remarkable mechanical properties. In many tropical and subtropical countries bamboo is available in suitable dimensions for a reasonable price. Therefore it is used for many purposes which range from the basket production up to the industrial production of parquet or paper. However, bamboo is known as susceptible to fungal or insect attack and it is difficult to treat with preservatives. Therefore BFH investigated the possibility to protect bamboo by other methods and tested the application of a heat treatment. European grown bamboo (Phyllostachys viridiglaucescens) and Asian grown bamboo (Phyllostachys pubescens) were heat treated and were subsequently inoculated with the basidiomycetes Coniophora puteana, Coriolus versicolor and Schizophyllum commune in an agar block test. Further the durability of treated specimens against soft rot fungi was tested. The changes of the mechanical properties (MOE and shock resistance) caused by the heat treatment were determined too. The application of temperatures above 200°C caused a clearly enhanced durability against a basidiomycete as well as against a soft rot attack but the shock resistance was intensely reduced. Further investigations are still ongoing. The study has been carried out with financial support from the Commission of the European Communities, specific INCO programme INCO-DC 961344.
H Leithoff, R-D Peek


The effects of heat treament on the specific gravity of beech and spruce wood
2003 - IRG/WP 03-40254
The effects of heat treatment on specific gravity of beech (Fagus orientalis) and spruce wood (Picea orientalis) naturally grown and intensively used in forest products industry in Turkey were studied. The wood samples were cut into 2 x 2 x 3 cm. Heat treatment was than applied to the wood samples at four different temperatures (130 °C, 150 °C, 180 °C and 200 °C) and three different durations (2 h, 6 h and 10 h) under air atmospheres. The results indicated that the specific gravity values treated by heating generally exhibited a decrease with increasing the exposure durations and temperatures compared to the untreated wood samples.
S Yildiz, Ü C Yildiz, G Colakoglu, E D Gezer, A Temiz


Developments in wood preservation processing techniques in New Zealand
1980 - IRG/WP 3143
P Vinden, A J McQuire


The Effect of Heat on the Retention of Ammoniacal Copper Quat (ACQ-AB) onto Scots Pine (Pinus Sylvestris L.) Wood
2008 - IRG/WP 08-40390
In this study, the sapwood of Scots pine (Pinus sylvestris L.) were treated with ammonical copper quat type (ACQ-AB), which is one of the environmentally friendly wood preservatives, by using soaking method as a functions of various temperatures and time. The results indicated that the retention behaviour of ACQ onto the wood was considerably affected by temperature of ACQ solution and treatment time.
M Hakki Alma, A Mukremin Kara


Evaluation of Barrier Wrap Systems after 71 Months of Exposure
2013 - IRG/WP 13-40631
A 71 month study of the performance of booted samples in ground contact was conducted in AWPA hazard zone 4. Data indicated that excellent performance of wrapped systems, even over untreated wood, could be obtained. Instances of decay colonization or termite attack could all be attributed to some breaking of the integrity of the barrier system. Good performance for treatment below ground contact threshold was demonstrated.
H M Barnes, M G Sanders, G B Lindsey, C McIntyre


Durability of different heat treated materials from industrial processes in ground contact
2005 - IRG/WP 05-40312
In this study the durability of heat treated wood originating from four different European industrial heat treatment processes in ground contact was examined. The manufacturers of heat treated material were: PLATO Hout B.V./Netherlands, Thermo Wood/Finland, New Option Wood/France and Menz Holz/Germany where Oil-Heat treated Wood (OHT) is produced. All heat treated materials showed significantly increased durability against decay in ground contact compared to untreated Scots pine (Pinus sylvestris L.), independent from the different heat treatment processes. After four years of field testing, heat treated material appears to be not suitable for in ground contact application, since long service life is required. In analogy to the classification of natural durability (EN 350-1, 1994), durability classes in the range from 2 (durable) to 4 (slightly durable) were achieved by the different heat treated materials. This stands in contrast to statements of suppliers, who promote their material as suitable for in ground applications.
C R Welzbacher, A O Rapp


The effects of heat treatment on the toughness of beech wood
2004 - IRG/WP 04-40283
The effects of heat treatment on toughness of beech (Fagus orientalis) wood naturally grown and intensively used in forest products industry in Turkey were studied. The wood samples were cut into 5 x 5 x 5 cm. Heat treatment was than applied to the wood samples at three different temperatures (130 °C, 150 °C and 180 °C) and three different durations (2 h, 6 h and 10 h) under air atmospheres. The results indicated that the toughness values treated by heating generally exhibited a decrease with increasing the exposure durations and temperatures compared to the untreated wood samples.
S Yildiz, Ü C Yildiz, E D Gezer, Ali Temiz, E Dizman


The effects of heat treatment on anatomical changes of beech wood
2004 - IRG/WP 04-40284
The effects of heat treatment on anatomical changes of beech wood (Fagus orientalis) naturally grown and intensively used in forest products industry in Turkey were studied. The wood samples were cut into 2x2x3 cm and than conditioned at 25 °C and 65 % relative humidity for 3 weeks. Heat treatment was than applied to the wood samples at four different temperatures (130 °C, 150 °C, 180 °C and 200 °C) and three different durations (2 h and 10 h) under air atmospheres. The anatomical changes were determined for each heat treatment variation.
Ü C Yildiz, Z Gerçek, B Serdar, S Yildiz, E D Gezer, E Dizman, A Temiz


Heat treated timber in Finland
2000 - IRG/WP 00-40158
Heat treatment permanently changes the physical and chemical properties of wood by means of high temperatures (150 - 240°C). Heat treatment darkens the colour of the wood. Heat treatment improves the equilibrium moisture content of the wood and the shrinkage and swelling of the wood is reduced. Very high temperatures improve the resistance to rot and also reduce the susceptibility to fungal decay. At the same time the strength properties of the timber are reduced: the bending strength can fall by 30%, depending on the treatment conditions and the cleavage strength (tensile strength perpendicular to fibres) may be reduced to a half, which makes heat treated timber split easily. The improved characteristics of heat treated timber offer the timber product industry many potential and attractive new opportunities. Also wood species having no commercial value as such can be heat treated and in this way new uses can be found for these species.
T Syrjänen, E Kangas


A collaborative test to determine the efficacy of poyurethane coatings on wood samples exposed in the marine environment. 1st Interim Report
1988 - IRG/WP 4145
Wood samples coated with elastomeric polyurethane (ca. 50 mils thick) were exposed for up to 2 years in 12 tropical and temperate marine test sites with known teredinid, pholad and/or crustacean infestations. All uncoated control samples were destroyed or partially destroyed. Polyurethane-coated samples were not attacked, the surfaces of the coating were sound and the polyurethane adhered well to the wood samples.
R A Eaton


Radio frequency heating times for sterilization radiata pine solid piles
2017 - IRG/WP 17-40815
In this work was sterilized wood packaging material of radiata pine, stacked as solid piles without stickers, for determining the heating times using radiofrequency treatment. The experiments were performed in a radio frequency semi-industrial equipment. The results showed that the radio frequency heating times increases with wood volume and that radio frequency treatments were faster than conventional vapour heat treatment.
H Esquivel, V Sepúlveda, J Torres, L Salvo, R A Ananías


Heat treatment of wood strands for OSB production: Effect on the mechanical properties, water absorption and dimensional stability
2002 - IRG/WP 02-40238
The effect of heat treatment on the mechanical and physical properties of commercial OSB strands was evaluated. Heat treatment was applied under inert atmospheric conditions to wood strands. The aim of this study was to examine the heat treatment parameters to achieve significant reduction of thickness swelling (upon exposure to moisture in service) without causing excessive reductions in strength. Heat treatments of 200, 210, 220, 230, 240, 250, and 260°C for 20 minutes were applied and swelling tests were performed. Subsequently the modulus of rupture and modulus of elasticity were measured in wood strands. High temperature treatments resulted in significant reductions in thickness swelling of wood strands but resulted in 20% reductions of modulus of rupture and modulus of elasticity.
G J Goroyias, M D C Hale


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