Your search resulted in 131 documents. Displaying 25 entries per page.
Image analysis for mould and sapstain detection on wood
2013 - IRG/WP 13-20519
Laboratory tests for mould growth on wood products are time consuming and rely on visual assessments of specimens utilizing subjective rating systems. Accelerated laboratory methods are needed that can provide rapid, quantitative assessment of mould and sapstain growth on solid and composite wood products. Image analysis of scanned spore imprints from southern pine or oriented strandboard (OSB) sp...
C A Clausen, V W Yang
Method for determining the critical moisture level for mould growth on building materials
2013 - IRG/WP 13-20530
The natural conditions of relative humidity (RH) and temperature (T) in different parts of a building is rarely constant over time. Instead, RH and T often vary cyclically and may pose a risk of mould growth as these conditions are the two key environmental parameters that controls mould growth. Consideration to both humidity and temperature conditions and the susceptibility to mould in a material...
A Ekstrand-Tobin, P Johansson, G Bok
Modelling the risk for mould growth on timber stored outdoors protected from rain
2013 - IRG/WP 13-20529
A mould resistance design (MRD) model was used to calculate the maximum duration of storage of timber outdoors under cover (protected from rain) before the onset of mould growth on the surface of wood. The prediction model is based on laboratory tests performed in constant and cyclic climates and were also confirmed against exposure tests in attics and crawl spaces. The prediction model presented ...
E Frühwald Hansson, S Bardage, S Thelandersson
Critical moisture levels and mould resistance of five different wood treatments
2013 - IRG/WP 13-30632
Mould resistance of five different treatments were tested using two methods, a recently
developed method for the determination of critical moisture levels of building materials (RHcrit),
and ASTM D3273-94. The critical moisture level method exposed samples at 22 °C and 98, 92,
86 and 82% relative humidity (RH) for 12 weeks. ASTM D3273-94 was performed at 29 °C and
about 95% RH.
Treatments c...
G Bok, P Johansson, A Ekstrand Tobin, S Bardage
Using hyperspectral imaging to detect and quantify mould and blue stain on coated and uncoated wood
2014 - IRG/WP 14-10822
Hyperspectral imaging has been applied on the surface of samples of coated and uncoated Norway spruce (Picea abies) as a new technique to detect and quantify growth of mould and blue stain fungi. Principal Component Analysis of the hyperspectral images resulted in a clear visualization of the fungi and the amount of mould coverage could be estimated. This indicates that NIR hyperspectral imaging c...
L Ross Gobakken, I Burud, A Flø, K Kvaal, T K Thiis
Effects of UV Radiation on Melanization and Growth of Fungi Isolated from Weathered Wood Surfaces
2015 - IRG/WP 15-10842
This research tests the hypothesis that fungi isolated from weathered wood will respond to elevated levels of UV radiation by increasing their melanin production. To test this hypothesis, we measured the melanin production and mycelial color of Aureobasidium pullulans and Cladosporium cladosporioides, before and after the fungi were grown under artificial UV, visible light and complete darkness. T...
V A Hernández, P D Evans
Short-term protection of palm wood against moulds and decay fungi by environment-friendly organic acids
2015 - IRG/WP 15-10843
Felled palm trunks are susceptible to fungi as long as their moisture content is above fibre saturation. During this period, it has to be protected against moulds and decay fungi. The study tested environmental-friendly organic acids for their protecting efficiency. Small samples of Date palm (Phoenix dactylifera) and Oil palm (Elaeis guineensis) wood were treated with weak organic acids and subse...
M Bahmani, O Schmidt
Development of a rapid screening method to determine the susceptibility to mould growth of novel construction and insulation products
2015 - IRG/WP 15-20562
Wood-based materials are commonly used in building construction/insulation as a replacement for solid timber. However, these materials are susceptible to microbiological growth and different environmental conditions influence the vulnerability of wood-based materials. Moulds are a common problem found within homes and cause aesthetic damage, health problems and can increase material vulnerability ...
B K Stefanowski, S F Curling, E Mansour, G A Ormondroyd
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
The resistance of composite boards protected with azole and inorganic nanoparticles to basidiomycetes and moulds
2015 - IRG/WP 15-40688
This paper presents a study on the resistance of wood composite boards, glued with silicone adhesive and obtained from chips of Scots pine Pinus silvestris L. and willow Salix viminalis L., to basidiomycetes and mould. The boards were protected in the production processes with fungicides based on metal nanoparticles, as well as on derivatives of 1,2,4-triazole, benzimidazole, and thiazole. The bio...
J Zabielska-Matejuk, I Frąckowiak, A Stangierska
Formation of biofinishes on outdoor exposed wood; the impact of wood-oil combination and geographical location
2016 - IRG/WP 16-10864
Growth of dark moulds enables the use of a decorative and protective biofinish for wood, showing advantages compared to traditional wood-coatings in terms of sustainability and self-repair. Based on the formation of a uniform mould covering on oil treated wood during outdoor exposure, the utilisation of a biofinish is in development. Basic information is lacking on the correlation between exposure...
E J van Nieuwenhuijzen, L Ross Gobakken, M F Sailer, R A Samson, O C G Adan
Simulation of surface climate and mould growth on wooden façades
2016 - IRG/WP 16-20585
The weathering of wooden surfaces is normally caused by mould growth, lignin deterioration and leaching of extractives. For well insulated buildings, the effect of the interior climate on the outer surface is small and sometimes negligible. This paper describes simple models for surface temperature and moisture conditions on a wooden façade that can further be used to model weather degradation an...
T K Thiis, I Burud, D Kraniotis, L Ross Gobakken
Activity of wood preservatives against mould fungi
2016 - IRG/WP 16-30695
The resistance of experimental and commercial wood preservatives to mould fungi was determined using a method recommended by the Building Research Institute Instruction. The research of the inhibiting actions of the growth of fungi was carried out on the Scots pine wood Pinus sylvestris L. and beech Fagus sylvatica L. The most active compounds against mould were experimental herbicidal ionic li...
J Zabielska-Matejuk, A Stangierska
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
Fungal growth on coated wood exposed outdoors: influence of coating pigmentation, cardinal direction and inclination of wood surfaces
2017 - IRG/WP 17-10896
The objective of the SERVOWOOD project was to develop and establish European Standards that will facilitate the prediction of service life for exterior wood coatings. One of the objective of this project was to study fungal growth of the field exposed panels. Two coatings applied in 2 and 3 coats were exposed for one year outdoors at 45° south: one solventborne (alkyd based) and one waterborne (a...
L Podgorski, C Reynaud, M Montibus
An experimental study of mould growth and wood decay in timber frame walls
2017 - IRG/WP 17-20623
This paper deals with parameters related to the occurrence of mould growth and wood decay in timber frame walls. In a first part, the hygrothermal conditions inside a timber frame wall finished with brick veneer cladding are analysed to get an idea of possible moisture related problems. It is shown that, based on the VTT mould prediction model, there is a mould risk on the interface between the in...
M Vanpachtenbeke, J Van den Bulcke, I De Windt, J Langmans, S Roels, J Van Acker
Bio-friendly wood protection systems - resistance to mould and blue-stain fungi
2017 - IRG/WP 17-30713
With stricter restrictions on the use of biocides and increasing environmental awareness there is a pronounced need for effective bio-friendly protection systems in the wood preservative and wood coating industry. One of the possible pathways is to exploit and utilize natural substances with active biological effects. Silanes, caffeine, natural oils and potassium carbonate were chosen as compounds...
L Ross Gobakken, W Perdoch, B Mazela, P Kwaśniewska-Sip, G Cofta
Susceptibility to filamentous fungi of plywood for furniture coated with waterborne acrylic lacquers
2017 - IRG/WP 17-40778
Filamentous fungi (mould), thanks to their little trophic requirements belong to organisms which grow exceptionally easy and fast in favorable hygrothermal conditions and attack both organic and inorganic materials even with only trace amounts of organic substances on the surface. The fungi often cause spoilage of foodstuffs, worsen the aesthetic of wood-based elements, and pose a threat to the en...
A Fojutowski, M Nowaczyk-Organista, P Hochmańska
Multivariate modeling of mould growth in relation to extractives in dried Scots pine sapwood
2017 - IRG/WP 17-20629
Influence of extractives on mould growth on Scots pine sapwood dried in air or in kiln was studied. Boards were sprayed with water mixtures of spores of the fungal species Penicillium sp., Aspergillus sp., Mucor sp., Paecilomyces sp., Trichoderma sp., treated at a temperature of 22ºC at 90% RH, classified into a percentage of covered area. Acetone and water extracts were isolated and analyzed for...
O Karlsson, O Myronycheva, M Sehlstedt-Persson, M Öhman, D Sandberg
Colour changes in unpainted wooden façades – Fifty Shades of Grey
2018 - IRG/WP 18-10903
In Norway the use of weathered unpainted, wooden façades has increased in popularity the last 20 years, both in single family houses as well as in multi-story and non-residential buildings. The benefit of using unpainted wood as façade material can be several: low maintenance costs, low environmental impact and low carbon footprint as well as contemporary and trendy aesthetic appearance.
The va...
K Zimmer, L R Gobakken, O Flindall, M Nygaard
Visual appearance of unpainted wooden claddings during the first year of outdoor exposure: Evaluation of surface mould growth, lightness (L*) and wasp attack
2018 - IRG/WP 18-40841
This study addresses changes in visual appearance of unpainted wood materials exposed outdoors. Specimens of Norway spruce (Picea abies) Scots pine (Pinus sylvestris), aspen (Populus tremula), acetylated Radiata pine (Pinus radiata) and DMDHEU-modified Scots pine sapwood were exposed facing south in Ås, Norway for 60 weeks. During this period, surface mould growth development and wasp attack were...
S Karlsen Lie, L Ross Gobakken, G I Vestøl, O Høibø
Thermally modified timber treated with methacrylate
2018 - IRG/WP 18-40849
Thermally modified timber (TMT) from Scots pine sapwood similar to Thermo-D quality was impregnated with methacrylate resin by the hot-and-cold method and subsequently cured at elevated temperatures. The results showed that methacrylate resin could be used to reduce colouring of painted TMT wood during accelerated weathering probably by hindering the migration of extractives. The resin itself did ...
O Karlsson, O Myronycheva, DJones, D Elustondo, D Sandberg
Comparative performance of wood/wood-based claddings predicted by four hygrothermal simulation tools
2019 - IRG/WP 19-20646
A number of hygrothermal numerical simulation packages are available, either wholly or partially dedicated to heat, air and moisture transfer simulations of building materials and wall assemblies. The objective of this work was to compare the hygrothermal responses and the moisture performance of western red cedar and composite wood claddings of a wood frame wall as predicted by four hygrothermal ...
M Defo, M Lacasse, A Laouadi
Preservative Treatment of CLT: An Example at Shimojishima Airport
2019 - IRG/WP 19-30748
Cross laminated timber (CLT) is a relatively new construction method that allows multi-storey construction using solid wood instead of concrete or steel. It is a method favoured by progressive architects and recognized for its much lower environmental footprint. Wood is an excellent construction material and is a long-term carbon sink that also performs well in the event of earthquakes and fire....
J Lloyd, N Yamashita, A Taylor
The impact of additional interior layers to the moisture dry-out and mould growth risk of CLT walls
2019 - IRG/WP 19-40876
The objective of this study was intended to determine the maximum allowable initial moisture content for CLT walls having both exterior and interior thermal insulation. A laboratory test was conducted, for which four test walls with two different insulation solutions and two different initial moisture contents were built. Based on the test results a simulation model was configured and simulations ...
V Kukk, J Kers, T Kalamees