Your search resulted in 37 documents. Displaying 25 entries per page.
Onset of mould growth – the effect of climate variability and different geographic locations
2010 - IRG/WP 10-20446
This paper presents a study on how climate conditions at numerous locations in Sweden affect the risk of onset of mould on wood sheltered outdoors. The results indicate that the risk is clearly higher in the south compared to the north of Sweden. These differences are mainly explained by colder and dryer winter periods in the north which is unfavorable for development of mould. The results also sh...
M Häglund, T Isaksson, S Thelandersson
Adsorption boundary curve influenced by step interval of relative humidity investigated by Dynamic Vapour Sorption equipment
2011 - IRG/WP 11-40547
The adsorption of water vapour from dry conditions by Norway spruce sapwood has been investigated using Dynamic Vapour Sorption (DVS) instrumentation. This equipment allows a fast and easy data acquisition as well as enables detailed studies of sorption properties using very small sample masses. In this study, particular focus was paid to the effect of step size on the sorption isotherms. Furtherm...
E Tang Engelund, M Klamer, T Mark Venås
Effects of microclimate, wood temperature and surface colour on fungal disfigurement on wooden claddings
2012 - IRG/WP 12-20490
Wooden claddings are common in façades in Norway, and Norway spruce (Picea abies) is the most frequently used species. The cladding is a major part of the facade, and it has visual requirements that may define the aesthetic service life. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more of...
L Ross Gobakken, G I Vestøl
Activities of moulds on wood as a function of relative humidity during desorption and absorption processes
2013 - IRG/WP 13-10794
Three different types of indoor moulds: Penicillium brevicompactum, primary colonizer; Alternaria tenuissima, secondary colonizer and Trichoderma harzianum, tertiary colonizer, grown on wood were measured for their activities under different relative humidity levels. The activities were measured by isothermal calorimetry. The activities of the moulds changed with the change of the relative humidit...
Yujing Li, L Wadsö
Experiences with an industrial system for controlled thermal wood modification in pressurized unsaturated steam
2014 - IRG/WP 14-40678
Thermal wood modification in pressurized reactors has a long history, but these processes are to date industrially scarcely used, because of the relatively complicated process equipment, compared to the more common high-temperature processes in kilns at atmospheric pressure. However, based on our practical experience with the FirmoLin® process, supported by recent scientific findings, it is foun...
W Willems
Mould growth on spruce claddings and the effect of selected influencing factors after 4 years of outdoor testing
2015 - IRG/WP 15-30671
Norway spruce (Picea abies) is the most frequently chosen wood species as claddings in façades in Norway, and is used both coated and uncoated. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more often growth of mould and blue stain fungi is the main challenge. A field test with synchronous monitoring of relative humidity, air temperature, material temperature and wood moisture content in Norway spruce claddings has been performed in southern Norway as part of the ClimateLife project. Visual evaluation of blue stain and mould growth according to EN 927-3 was performed, and evaluation data after 46 months exposure is presented. The objectives were to study the effect of 1) environment, 2) cardinal direction and 3) colour of the coated surface on growth of blue stain and mould fungi and to study the variation in relative humidity, air temperature, wood moisture content and material temperature. After 46 months exposure, the red coating system had generally the lowest mould ratings and the uncoated claddings had the highest. Of the white coloured claddings the ones facing south had lower mould ratings than those facing north, but the opposite were found for red coloured claddings. The relative humidity was higher in front of claddings exposed northwards and in a shaded environment compared to an open environment against south. In an open environment red coloured claddings had the lowest wood moisture content and highest material temperature, and red coloured claddings against south had the highest maximum material temperature.
L Ross Gobakken, G I Vestøl
Effects of climatic factors and material properties on mould growth on untreated wooden claddings
2017 - IRG/WP 17-10884
Mould growth is an important contributor to colour change of untreated wood exposed outdoors. Predicting the development of mould growth is therefore important to ensure successful use of untreated wood as a façade material. More knowledge about the factors affecting mould growth on outdoor exposed wood is required to give better predictions. In this study, climatic factors and material propertie...
S Karlsen Lie, G I Vestøl, O Høibø, L Ross Gobakken
Controlled deposition of copper nanoparticles using wood inherent architecture as natural template
2017 - IRG/WP 17-40783
As one of the most abundant renewable biomass resources, wood can be used as templates for synthesizing functional nanoparticles with controlled shapes and sizes. In this study, copper nanoparticles were synthesized with controlled shapes and sizes using poplar wood as the natural inexpensive and renewable templates. The crystal structure and morphologies of the copper nanoparticles were character...
Youming Dong, Kaili Wang, Yutao Yan, Jianzhang Li, M Hughes, Shifeng Zhang
Impact of temperature and relative humidity on spatio-temporal fungal growth dynamics of Basidiomycetes
2018 - IRG/WP 18-10905
Basidiomycetes can cause considerable damage to wood and other bio-based building materials. Knowing at which environmental conditions these decay fungi generally thrive, and how the environmental conditions affect fungal growth characteristics, is therefore of particular interest. In this paper, we use image analysis to assess the impact of the environmental conditions on the growth dynamics of C...
L De Ligne, G Vidal-Diez de Ulzurrun, J Van den Bulcke, J M Baetens, B De Baets, J Van Acker
Monitoring of the building made of CLT in Ljubljana
2019 - IRG/WP 19-40860
Wood is one of the most important construction materials and its use in building applications has further expanded in recent decades, predominately due to development of the modern composites, like cross-laminated timber. In order to enable even more extensive and reliable use of wood in outdoor applications, factors affecting wood’s service life need to be understood. It is well known that fung...
M Humar, D Krzisnik, B Lesar, N Thaler, B Dujic
Joints design considerations in indoor high humidity conditions
2022 - IRG/WP 22-40950
In recent years, a number of cases of degradation by wood destroying fungi have been detected in covered timber structures such as pools, wineries, bathrooms, etc. – in fact, any building where indoor air may reach high humidity values during certain periods of time.
The origin of this kind of decay was not related to water leaks, but to the condensation of the water vapor over the steel connec...
A Lozano, D Lorenzo, M Alonso, F Álvarez, J E Martínez
Performance of Douglas-fir cross laminated timber (CLT) subjected to elevated humidity in a ground proximity field test for 6 years
2024 - IRG/WP 24-41010
The ability of insecticidal soil drenches or spray-on insecticide/fungicide treatments to protect mass timber elements exposed in a high moisture environment but out of direct soil contact was assessed using a modified AWPA ground proximity test established in 2017. Three-ply Douglas-fir CLT pieces measuring 305 x 355 x 105 mm (L x H x W) were installed at the Harrison Experimental Forest (HEF) (S...
M E Mankowski, J J Morrell, T G Shelton, G T Kirker