Search

Abstract Surface mould growth contributes to the colour changes of outdoor exposed wood over time. Modelling mould growth can thus help visualize wooden facades' colour development, which can improve facade design and service life. However, existing wood mould models do not consider transient wetting effects that occur outdoors due to precipitation and condensation. To address this, four mould models were evaluated using laboratory experimental data that included exposure to transient wetting. First, the models (the original and the updated VTT model, the biohygrothermal model and the mould resistance design (MRD) model) were evaluated for Scots pine sapwood. For this evaluation, the transient wetting effect was implemented in the models by using hourly wood surface relative humidity (RH), calculated from electrical resistance measurements, as input. This showed that the original and the updated VTT model gave best fit to the experimental data. However, further evaluation of these two models for more wood materials showed that the updated VTT model was sensitive to the choice of material parameters. Large discrepancies occurred when varying the material parameters in the updated VTT model. Finally, different estimates of RH were tested in the original VTT model. Using wood surface RH as input gave best fit to the experimental data, and ambient air RH gave poorest fit. Overall, the results indicate that the original VTT model is fairly reliable and can be used to predict mould growth on wooden claddings exposed to transient wetting as long as the wood surface climate is used as climatic input data. Highlights • Four existing mould growth models were evaluated using experimental data. • Eight climatic conditions and eight wood materials were included in the evaluation. • The transient wetting effect was implemented in the models by using wood humidity as input data. • The original VTT model gave the most reliable estimates. [ABSTRACT FROM AUTHOR]

This work presents the summarized results based on eight large-scale tests carried out to study the fire behaviour of vertical wooden façade combustion. The main purpose of these tests is to get some information on fire spread along a combustible façade in order to assess the ability of numerical codes to simulate flame propagation. If many researches on combustible façades exist, it is difficult to find academic configurations with a large instrumentation and consequently with a large database.Generally, these studies focus on observations concerning fire behaviour of complex façades, and for most of them, instrumentation consist to measure the temperature at different levels.During the eight large-scale tests have been measured: the temperatures in the fire room, on the façade and in front of it at different levels, the mass loss of wood cribs used as fuel in the room fire as well as the components of combustion gases.The first two tests were made without any combustible cladding on the calcium silicate board in order to measure the temperature of an inert façade. The façade of the other tests were composed of a cladding of 18 mm thick plywood mounted directly onto the calcium silicate board. In these tests, two different species of wood are used, Birch Wood and Okoumé (African Wood). The aim was to observe the influence of the speeches with different densities on flame propagation. In addition to the numerous temperature measurements mentioned above, measurements of residual claddings thickness were made. Thus, the present research tries to understand the influence of the thermal stress level along the façade to the wood-burning rate through the wall. [ABSTRACT FROM AUTHOR]

3D visualization is one of the forms of presentation of spatial phenomena, which, thanks to the development of new technologies of acquiring, modeling and providing spatial information, is one of the most popular methods of presenting real objects in the virtual world. Practice shows that 3D visualization is increasingly being used by different entities to present research results in 3D form, thereby ensuring better readability of the papers. The paper describes the methodology of 3D visualization of the influence of atmospheric conditions on wooden facades of a school building. Methods of obtaining data for the purpose of creating a 3D model of a research object, processing vector and raster data, and rendering the final animation were described. The results of the study show that the use of 3D visualization as a form of presenting research results enables accurate estimation of the intensity of atmospheric conditions on the vertical elevation, taking into account the exact geometry of the research object. [ABSTRACT FROM AUTHOR]

The hygrothermal surface conditions of a façade is important for the degradation of the façade material as well as for the energy budget of the building. The distribution of short term variations of the temperature and moisture in the façade is often neglected in degradation studies that will typically treat the whole façade equally. The moisture and temperature variations are especially important in porous building materials where water dependent biological and physical processes are the main degrading factors. In this study the diurnal cycle of the surface temperature is measured with conventional temperature probes as well as with infra-red camera. In addition, the moisture content of the wooden façade is measured with resistive measurement technique. The measurements are used to validate simulations of the spatial temperature and moisture variations on the façade. The study shows large variations of surface conditions on the façade and that the simulations reproduces the measurements within a high degree of accuracy. [ABSTRACT FROM AUTHOR]

The outer facade constitutes a substantial volume of the total consumption of materials used in a building and the need for maintenance of the facade makes it especially interesting from a life cycle perspective. The range of wooden materials and products used for facades has different impacts over the life cycle, but the analyses so far have not included a time-adjusted global warming potential (GWP). Wooden facade materials were assessed with respect to their life cycle carbon footprint based on the environmental product declarations (EPD) and adjusted according to EN15804. The results showed low impacts of untreated Scots pine heartwood (≈1 kg CO2-eq. per square meter [m2]), medium for thermally modified Scots pine, coated Norway spruce and oil/copper–organic preservative-treated Scots pine (1–5 kg CO2-eq. per m2) and high for furfurylated Scots pine and acetylated Radiata pine (5–10 kg CO2-eq. per m2). The results with time-adjustment showed that these methods have a potential large effect on the carbon footprint of wooden claddings. The inclusion of biogenic carbon flows and timing seems to be more important than the difference between the product when biogenic carbon is not included. This fact highlights the importance time-adjusted GWP would have for wood products EPDs. [ABSTRACT FROM AUTHOR]

This study represents for the first time a comprehensive assessment of functionality and environmental impacts of metallic silver nanoparticles (Ag-NP) compared to conventional organic biocides. Four different transparent, hydrophobic coatings of wooden outdoor façades were tested during one year outdoor weathering. The total silver release from products with Ag-NP was proportional to the overall erosion of the coating. The results indicate that the Ag-NPs are likely transformed to silver complexes, which are considerably less toxic than ionic silver. The protective effect of the silver containing coatings against mold, blue stain and algae was insufficient, even in immaculate and non-weathered conditions. The release of organic biocides from conventional coatings was dependent on the weather conditions, the type of biocide and the use in the base or top coat. The conventional coating showed a good overall performance free from mold, blue stain and algae until the end of the test period. [Copyright &y& Elsevier]

Mould growth on coated wood is today a genuine challenge for house owners. Environmentally sound wooden facades with long service lives and acceptable appearance are desired. The objective in this study was to investigate the accumulated mould growth on 13 different wood substrates with 3 surface coating systems by identifying the factors that contribute to the variation and to predict future performance. A generalized linear mixed model was fit to the data with the analysis showing that coating and exposure time both had highly significant influences on mould growth. Further, wood substrate was significant, but comparatively less than coating and exposure time. A smaller coefficient for mould coverage in the beginning of the exposure period gave the panels with one of the coating systems, BAP, a delay in mould growth, and the extrapolated values for years 6–12 indicate a longer aesthetic service life than panels with the two other coating systems. Coated heartwood as wood type was less susceptible to mould growth than coated mixed wood and coated sapwood. Acetylated pine as wood substrate and aspen as wood species had lower resistance to mould growth than the other wood substrates and wood species, respectively. [ABSTRACT FROM AUTHOR]

Mediating between forest and garden, tradition and modernity, a small wooden gate at Alvar Aalto's Villa Mairea is shown to be deeply rooted in Finnish cultural memories. [ABSTRACT FROM AUTHOR]

Analyzes the reliability of timber fender systems in waterfront facilities. Level of performance in existing timber fender systems; Target performance levels for composite replacement components; Effect of variability and correlation among material properties on structural reliability; Effect of load-duration assumptions on structural reliability.

Examines the form and function of the wooden frontages applied to stone houses in the late medieval and early modern period in Scotland and how these structures relate to the ways in which streets were progressively narrowed by advancing frontages. Details of a 1751 property dispute in Stirling; Encroachment of buildings on the street; References to forestairs in 17th-century Stirling manuscript sources.