NUMERICAL SIMULATION OF DYNAMIC MOISTURE SPREAD IN COMPACT FLAT ROOFS
Keywords:
dynamic evaluation, compact flat roof, moisture content, WUFI 2D softwareAbstract
The contribution is focused on the numerical verification of the correct design of compact flat wooden roofs in the external boundary conditions of Central Europe (Vienna – Bratislava); the internal boundary conditions of the analysis met the requirements for human habitation. Using the WUFI 2D software, the compositions of compact flat roofs were analyzed using a vapor barrier and a variable vapor retarder with a low dispersion of diffusion thickness values and a variable vapor retarder with a high dispersion of diffusion thickness values. Each of these three compositions was assessed in versions without shading and with shading of the surface (by graveling the roof covering from the exterior side). The length of the analyzed period was 5 years. The main goal was to verify the accumulation of moisture in layers of the structure and whether critical moisture conditions suitable for the formation of molds and fungi causing rot will be reached in any of the compositions. The measurement results showed the different functioning of compact flat wooden roofs depending on the shading, as well as other conclusions for the design and realization of the composition of compact flat wooden roofs.
References
Alev, Ü., Kalamees, T., 2016. Avoiding mould growth in an interiorly insulated log wall. Building and Environment, 105: 104-115.
Bachinger, J., Nusser, B., Bednar, J., Teibinger, M., 2016. Influence of an unvented air cavity at the cold side of the insulation in sun exposed wooden flat roofs, World Conference on Timber Engineering Vienna - Austria, August 22.-25.2016.
Björk, F., Enochsson, T., 2009. Properties of thermal insulation materials during extreme environment changes. Construction and Building Materials, 2009, 23.6: 2189-2195.
EN 15026. Hygrothermal performance of building components and building elements – Assessment of moisture transfer by numerical simulation, 2007.
EN322. Wood-Based Panels-Determination of Moisture Content; Slovak Office of Standards, Metrology and Testing: Bratislava, Slovakia, 1995.
Geving, S., Lunde, E., Holme, J., 2015. Laboratory investigations of moisture conditions in wood frame walls with wood fiber insulation. Energy Procedia, 78: 1455-1460.
Glaser, H., 1959.Grapisches Verfuhren zur Untersuchung von Diffusionsvorgangen. Kaltetechnik, 11, 1959, 345-355.
Hill, D., 2003. Review of hygrothermal models for building envelope retrofit analysis. Research Highlights, Canada Mortgage and Housing Corporation, November, 1-4.
Kontoleon, K. J., Giarma, C., 2016. Dynamic thermal response of building material layers in aspect of their moisture content. Applied Energy, 170: 76-91.
Krus, M., 1996. Moisture transport and storage coefficients of porous mineral building materials. Theoretical Principles and New Test Methods. IRB-Verlag Stuttgart.
Künzel, H. M., 1995. Simultaneous heat and moisture transport in building components. One-and two-dimensional calculation using simple parameters. IRB-Verlag Stuttgart, 65.
Künzel, H. M., 2014. Accounting for unintended moisture sources in hygrothermal building analysis. Proceedings of the 10th Nordic Symposyum of Building Physics. Lund, Sweden, 15-19 June 2014, pp. 947-953.
Langerock, CH., Tilmans, A., De Mets, T., Lancour, X., Nguyen, E., Charron, S., Michaux, B., 2017. Hygrothermal behaviour of compact roofs in wood frame constructions through on-site measurements. Energy Procedia, 132: 813-818.
Mrlík, F., 1985. Vlhkostné problémy stavebných materiálov a konštrukcií [Moisture problems of building materials and constructions]. Vydavateľstvo ALFA Praha.
Nusser, B., Teibinger, M., Bednar, T., 2010. Messtechnische Analyse flachgeneigter hölzerner Dachkonstruktionen mit Sparrenvolldämmung—Teil 1: Nicht belüftete Nacktdächer mit Folienabdichtung - Metrological analysis of flat-sloping wooden roof structures with full rafter insulation—Part 1: Non-ventilated bare roofs with foil sealing. Bauphysik, 32.3: 132-143.
STN 73 0540-2+Z1+Z2., 2019. Thermal Protection of Buildings-Thermal Performance of Buildings and Components-Part 2: Functional Requirements; Slovak Office of Standards, Metrology and Testing: Bratislava, Slovakia.
Vidholdova, Z., Reinprecht, L., Krokošová, J., 2016. Náchylnosť dreva na mikrobiálnu kontamináciu baktériami a plesňami [Susceptibility of wood to microbial contamination by bacteria and fungi]. Proceedings of the International Conference CSTI 2015 Conservation Science, Technology and Industry, Bratislava, Slovakia, 7-9 October 2016; pp. 307-314.
Viitanen, H., Ritschkoff, Anne-Ch., 1991. Mould growth in pine and spruce sapwood in relation to air humidity and temperature. Swedish University of Agricultural Sciences.
Venäläinen, M., Harju, A.M., Kainulainen, P., Viitanen, H., Nikulainen, H., 2003. Variation in the decay resistance and its relationship with other wood characteristics in old Scots pines. Annals of forest science, 60.5: 409-417.
Wang, J.Y., Morris, P.I., 2010. A review on conditions for decay initiation and progression. In: 41st Annual Meeting of the International Research Group on Wood Protection, Biarritz, France, 9-13 May 2010. IRG Secretariat.
Wang, Y., et al. 2022. The impact of temperature and relative humidity dependent thermal conductivity of insulation materials on heat transfer through the building envelope. Journal of Building Engineering, 46: 103700.
Wta-Guideline 6-2. Simulation wärme- und feuchtetechnischer Prozesse. Draft Oct. 2013.
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