Your search resulted in 31 documents. Displaying 25 entries per page.
Microbiological degradation of wooden piles in building foundations
1988 - IRG/WP 1370
White rot, soft rot and bacterial attack have been detected in softwood piles under buildings. In some cases bacteria were found to be the main degradation organisms in the studied piles. The water content of degraded piles was very high. The compression strength was quite low also in the piles deteriorated by bacteria. The density of wood was very variable, and the degree of degradation could not...
L Paajanen, H Viitanen
Durability of larch (Larix spp.) wood against brown-rot fungi
1997 - IRG/WP 97-10228
Durability of the heartwood of Larix decidua, L. sibirica, L. gmelinii, L. gmelinii var japonica, L. gmelinii var olgensis and L. sibirica x decidua against brown rot fungi Coniophora puteana, Poria placenta and Gloeophyllum trabeum was tested according to EN 113 test method. Parallel samples were used to study the amount and composition of wood extractives. The sample trees originated from the re...
H Viitanen, L Paajanen, P Saranpää, P Viitaniemi
Decay fungi in Finnish houses on the basis of inspection samples from 1978 to 1988
1989 - IRG/WP 1401
A summary of the causes and sources of fungal damages was made on the basis of decay samples and sample information sent to the Forest Products Laboratory of the Technical Research Centre of Finland (VTT) between 1978 and 1988. About 50-130 decay cases in wood structures were studied annually. In almost 50% of all fungusdamage cases the cause was Serpula lacrymans. The proportion of Coniophora put...
L Paajanen, H Viitanen
Resistance of painted pine sapwood to mould fungi. Part 1. The effect of waterborne paints and fungicides on mould growth
1997 - IRG/WP 97-10233
The efficacy of different fungicides in acrylate and alkyd paints to protect pine sapwood against mould fungi was studied. The acrylate and alkyd paint systems with and without a preservative dipping treatment prior to painting were also used. Differences in the efficacy of the fungicides to protect the paint film were found. The paint films with isothiazolon and IBPC were resistant against mould ...
H Viitanen, P Ahola
Decay resistance of Scots pine (Pinus sylvestris) heartwood against brown rot
2002 - IRG/WP 02-10433
Natural decay resistance of wood is mainly restricted in the heartwood and based on wood microstructure and chemical composition. The genetic variation in the durability of Scots pine (Pinus sylvestris L.) wood against decay and the relationship between resistance and chemical composition was studied. The laboratory tests of 6 and 8 weeks were carried out with a brown rot fungus Coniophora puteana...
H Viitanen, A M Harju, P Kainulainen, M Venäläinen
Resistance of painted wood to mould fungi. Part 2. The effect of wood substrate and acrylate paint systems on mould growth
1997 - IRG/WP 97-10234
Resistance of acrylate paint systems on different types of pine and spruce sapwood to mould fungi was studied. Dipping into the preservative prior to painting, a primer with and without a fungicide (propiconazole + IPBC 0.50 + 0.2%) and a topcoat with and without a fungicide (propiconazole + IPBC 0.25 + 0.12%) were combinations of the treatments studied. The efficacy of the treatment systems varie...
H Viitanen, P Ahola
Moisture requirements and wood degradation of pine and spruce wood by some Basidiomycetes-fungi
1989 - IRG/WP 1406
The minimum moisture requirements for the growth of the brown rot fungi, Coniophora puteana, Gloeophyllum trabeum and Serpula lacrymans were near or above the fibre saturation point of pine and spruce, sap and heartwood, during 160 days incubation according to the standard method EN 113. The moisture of wood for the optimum growth of Coniophora puteana and Serpula lacrymans was about 35-80% and fo...
H Viitanen, A-C Ritschkoff
Preliminary studies of the decay mechanism of some brown-rot fungi
1989 - IRG/WP 1402
The importance of the enzymatic degradation of hemicellulose and cellulose by brown-rot fungi is still under discussion. Endo-ß-1,4-xylanase and endoglucanase activities of Coniophora puteana and Poria placenta cultures were measured by the increase in reducing groups. Enzymes were produced in liquid and solid sawdust based culture media. Enzyme activities were measured in two, four and eight wee...
A-C Ritschkoff, H Viitanen
Decay resistance of Siberian larch wood against brown rot fungi - Part 2. The effect of genetic variation
1998 - IRG/WP 98-10287
Wood natural decay resistance is mainly restricted in the heartwood part of tree and based on wood microstructure and chemical composition. However, the variation of decay resistant in different wood species is vide and the effect of genotype on decay resistance of Siberian larch wood grown in Finland is not known. The aim of this work was to find out the variation on decay resistance of Siberian ...
H Viitanen, L Paajanen, T Nikkanen, P Velling
The critical moisture and temperature conditions for the growth of some mould fungi and the brown rot fungus Coniophora puteana on wood
1988 - IRG/WP 1369
The growth of some mould fungi on pine and spruce sapwood was studied in 40 different constant moisture and temperature conditions. The temperature range was between +10 and +40°C and the relative humidities varied from 76 to 100% relative humidity (RH). The incubation time was 12 weeks. The mixed mould inoculation used included typical fungi growing on wood: Aspergillus versicolor, Cladosporium ...
H Viitanen, L Paajanen
Resistance of painted wood to mould fungi. Part 3. The effect of weathering, wood substrate and fungicides on mould growth
1998 - IRG/WP 98-10284
The effect of 6 month outdoor weathering on the resistance of acrylate paint systems on different types of pine and spruce sapwood to mould fungi was studied. Dipping into the preservative prior to painting, a primer with and without a fungicide (propiconazole + IPBC 0.50 + 0.2%) and a topcoat with and without a fungicide (propiconazole + IPBC 0.25 + 0.12%) were combinations of the treatments stud...
H Viitanen, P Ahola
Preservative effect of cellulose insulation material against some mould fungi and brown rot fungus Coniophora puteana in pine sapwood
1991 - IRG/WP 1484
The influence of mineral wool and loose-fill cellulose wool on biodeterioration of pine sapwood was studied. The test fungi were mould fungi Aspergillus versicolor, Cladosporium sphaerospermum, Penicillium sp. and Aureobasidium pullullans and brown rot fungus Coniophora puteana. Cellulose wool inhibited the growth of mould fungi on the face of wood contacted with insulation material at RH of 97 an...
Natural durability of 4 different Larix species tested in soil contact
2002 - IRG/WP 02-10434
Importers of Siberian Larch claimed to have a material which can replace pressure treated wood in soil contact. This gave reason to investigate the durability of 4 different Larix species (L. decidua, L. sibirica, L. decidua x sibirica, L. gmelini var ologenis) coming from 7 different origins in comparison with sapwood of Pinus sylvestris untreated as well as pressure impregnated with retentions o...
A O Rapp, H Viitanen, T Nilsson
The wood-attacking insects in wooden houses of an old open air museum in southern Finland
1989 - IRG/WP 1409
Harmful insects of wood in a open-air museum were investigated in 1985-1988 by order of the National Board of Antiquities and Historical Monuments of Finland in nine old log houses. Many thousands of insects and altogether 1073 anobiids (Coleoptera, Anobidae) were obtained by window and light traps. The most common Anobiidae-species were Hadrobregmus confusus (Kraatz) 60.3%, Hadrobregmus pertinax ...
H Viitanen, M Pulkkinen
Models of the critical time of humidity and temperature conditions for the development of mould fungi in pine and spruce sapwood
1995 - IRG/WP 95-20066
Regression models of the time factor for the growth of mould fungi in pine and spruce sapwood are studied. The first group of models are based on the results of exposures of mould fungi in static humidity and temperature conditions indicating the time for the start of mould growth in wood. The second group of models are based on the exposures of mould fungi in fluctuating or alternating humidity a...
Decay resistance of Siberian larch wood against brown rot fungus. - Part 3. The variation between plus trees and their grafted clones
2000 - IRG/WP 00-10350
The aim of the study was to estimate the variation in the decay resistance of Siberian larch (Larix sibirica Ledeb.) wood using mature plus trees and their grafted clones. Samples were collected with an increment core borer from 11 original plus trees and their 25-year-old grafted seed orchard clones. A typical brown rot fungus, Coniophora puteana (Schum. ex Fr.) Karst. (BAM Ebw. 15), was used as ...
H Viitanen, L Paajanen, M Venäläinen, A Harju, P Velling
The effect of heat treatment on the properties of spruce
1994 - IRG/WP 94-40032
The effect of high temperature treatment (above 150°C) on the wood quality is studied at the VTT. Improved dimensional stability, lower equilibrium moisture content and increased durability against biodeterioration is achieved, depending on the environmental factors. The biodeterioration resistance of spruce is improved due to changes in chemical composition and lower equilibrium moisture content...
H Viitanen, S Jämsä, L Paajanen, A J Nurmi, P Viitaniemi
New method to find out the volatile organic compounds (VOC) of wooden material
2000 - IRG/WP 00-20189
Volatile organic compounds (VOC) of pine, spruce and larch wood were studied using a new technique developed at VTT Chemical Technology. 50 mg of crushed wood material was placed into glass tubes. The tubes were closed with a glass wool, which is pressed with a tube cap. Wood samples were analysed with a gas chromatograph after thermal desorption using four different temperatures (50°C, 100°C, 1...
H Viitanen, K Villberg, K Saarela
Resistance of pine and spruce heartwood against decay - The effect of wood chemical composition and coating with water-borne wood oil product
2006 - IRG/WP 06-10597
Natural durability of wood has been widely studied, but the combination of the natural durability and different treatments has not been the focus of many studies. The durability of wooden products is mainly based on the water permeability and the resistance against organisms. In this study, the water absorption and decay resistance of sapwood and heartwood of Scots pine and Norway spruce were exam...
H Viitanen, S Metsä-Kortelainen, T Laakso
Evaluation of exposure conditions for wooden facades and decking
2009 - IRG/WP 09-20408
During their functional life, building components are exposed to moisture and other environment stress conditions in numerous ways. This is a fact that should be taken into account during manufacture, product development, designing and work execution of building components. For wood material, moisture stress and biological factors like mould and decay fungi are often critical in cladding and decki...
H Viitanen, T Toratti, R Peuhkuri, T Ojanen, L Makkonen
Testing of decay resistance of sapwood and heartwood of thermally modified Scots pine and Norway spruce
2010 - IRG/WP 10-40523
Thermal modification at elevated temperatures changes the chemical, biological and physical properties of wood. One of the main targets of thermal modification is to increase the biological durability and decay resistance of wood. Although the effects of thermal modification on wood have been widely studied, the significance of sapwood and heartwood on the resistance of thermally modified wood has...
H Viitanen, S Metsä-Kortelainen
Effect of Coatings on the Durability of Birch and Spruce Plywood. Part 1: Weathering Performance
2010 - IRG/WP 10-40526
Several different coated birch and spruce plywood types were investigated in Finland using outdoor weathering. The weather performance of the tested coated birch plywood was good compared with uncoated birch and spruce plywood. The paint base film coated and painted birch plywood performed well in outdoor testing at VTT's test site. Phenol film coated plywood was sensitive to UV light, but on...
A Nurmi, H Viitanen
Effect of Coatings on the Durability of Birch and Spruce Plywood. Part 2: Biological Durability
2010 - IRG/WP 10-40527
Several different coated birch and spruce plywood types were investigated in Finland using the combination of outdoor weathering and decay test EN 12038. The most important factor to affect on the biological performance of birch plywood, coated and uncoated, was edge sealing. For spruce plywood edge sealing had a smaller effect. However, in spite of positive effect against decay, edge sealing did ...
A Nurmi, H Viitanen
Quantitative design guideline for wood outdoors above ground applications
2011 - IRG/WP 11-20465
This paper describes the background and principles behind an engineering design guideline for wood in outdoor above ground applications, i.e. use class 3 according to EN 335. The guideline has been developed in the European research project WoodExter and can be seen as a first prototype for a quantitative design tool in the area of wood durability. It is based on a defined limit state for onset of...
S Thelandersson, T Isaksson, E Suttie, E Frühwald, T Toratti, G Grüll, H Viitanen, J Jermer
Report on COST E37 Round Robin Tests – Comparison of results from laboratory and field tests
2013 - IRG/WP 13-20535
A round robin involving 15 European participants was set up in 2006. The round robin consists of both a field test according to the double layer test method and a laboratory test with two different preconditioning methods. When comparing EN 84 preconditioning (two weeks water leaching) with natural preconditioning (1 year in field, above ground) according to CEN/TS 15397, no significant difference...
M Westin, E Conti, J Creemers, P-O Flæte, A Gellerich, I Irbe, M Klamer, B Mazela, E Melcher, R Möller, L Nunes, S Palanti, L Reinprecht, E Suttie, H Viitanen