Hygrothermal Assessment of Internally Insulated Prefabricated Concrete Wall in Polish Climatic Condition

Internal insulation of external walls is often problematic due to increased moisture content in the wall and interstitial or surface condensation risk. In this paper, the hygrothermal performance of prefabricated, concrete, large panel, external wall typical for WK70 system, commonly used in Poland in the 70’s, with inside, additional insulation was investigated. Thermal insulation board made out of hygroscopic, natural materials with moisture buffer capacity and extruded polystyrene (EPS) board was used as interior insulation. Experience with this natural insulation is rare in Poland. The analysis was performed using WUFI software. First of all, the impact of various standard boundary conditions on the behavior of the different wall assemblies was tested. The comparison of results showed that the moisture class according to the EN ISO 13788 leads to too high values of total moisture content in the wall since the boundary condition according to the EN 15026 should be usually applied. Then, hygrothermal 1D-simulations were conducted by WUFI Pro for analysis of internally added insulation, and the weak point like the joint of the wall with the concrete ceiling was verified using 2D simulations. Results showed that, in the Warsaw climate and the indoor conditions adopted in accordance with EN 15026, in the tested wall assemblies, regardless of the type of interior insulation, there would not be any problems with moisture - inside the structure and on the interior surface.


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[1] A. Holm, H. M. Künze, “The impact of the indoor Climat on the hydrothermal Behaviour and the durability of External Components – Standard Boundary Conditions vs. hygrothermal Indoor Climat Simulation” 11 BMC International Conference on Durability of Building Materials and Components, Istanbul, Turkey, 2008.
[2] A. Karagiozis, A. Desjarlais, H. M. Künzel, A. Holm. “The evolution of hygrothermal design: WUFI to WUFI-Plus” Journal of Building Enclosure Design, pp. 24-29, summer 2010.
[3] E. Latif, M. A. Ciupala, S. Tucker, D. Ch. Wijeyesekera, D. J. Newport, “Hygrothermal performance of wood-hemp insulation in timber frame wall panels with and without a vapour barrier”. Build. Environ, vol. 92, pp. 122-134, 2015.
[4] E. Vereecken, S. Roels, “A comparison of the hygric performance of interior insulation systems: A hot box-cold box experiment”, Energy and Build., vol. 80, pp. 37-44, 2014.
[5] E. Vereecken, S. Roels, “Capillary active interior insulation: do the advantages really offset potential disadvantages?” Materials and Structures, vol. 48, pp. 3009-3021, 2015.
[6] EN 15026:2008 - Hygrothermal Performance Of Building Components And Building Elements - Assessment of Moisture Transfer By Numerical Simulation.
[7] EN ISO 13788:2012 - Hygrothermal performance of building components and building elements. Internal surface temperature to avoid critical surface humidity and interstitial condensation. Calculation methods.
[8] H. M. Kunzel, “Simultaneous Heat and Moisture Transport in Building Components. One and two dimensional calculation using simple parameters”, IRB Verlag, Fraunhofer-Institut für Bauphysik, 1995.
[9] H. M. Künzel, T. Schmidt, A. Holm, “Exterior surface temperature of different wall constructions comparison of numerical simulation and experiment”, in: Proc. 11th Symposium on Building Physics, Dresden, Germany, 2002, pp.441–449.
[10] http://www.h-house-project.eu (2.03.2017)
[11] J. Grunewald, U. Ruisinger, P. Häulp, “The Rijksmuseum Amsterdam – hygrothermal analysis and dimensioning of thermal insulation” in Proc. 3rd International Building Physics/Science Conference, Montreal, 2006, pp. 345-352.
[12] J. Mlakar, J. Strancar, “Temperature and humidity profiles in passive-house building blocks”, Build. Environ. vol. 60, pp. 185–193, 2013.
[13] J. W. Lstiburek Joseph, “Understanding vapour barriers”, ASHRAE journal, vol.40, pp. 46.8: 40. 2004
[14] O. Hägerstedt, J. Arfvidsson, “Comparison of field measurements and calculations ofrelative humidity and temperature in wood framed walls, in: Zmeskal O. (Ed.), Thermophysics, Brno University of Technology, Faculty of Chemistry, Valtice, Czech Republic, 2010, p.9.
[15] P. Häulp, K. Jurk, H. Petzold, “Inside thermal insulation for historical facades in Research in Building Physics” in Proc. 2nd International Conference on Building Physics, Leuven, Belgium, 2003, pp. 463-469
[16] P. Wegerer, J. N. Nackler, T. Bednar, “Measuring the Hygrothermal Performance of an Interior Insulation made of Woodfibre Boards”. Energy Procedia, vol. 78, pp. 1478–1483, 2015.
[17] Polish law: Dz.U. poz.926,(2013),Rozporzzenie Ministra Transportu, Budownictwa I Gospodarki Morskiej zmieniające rozporządzenie w sprawie warunków technicznych, jakim powinny odpowiadać budynki i ich usytuowanie (in polish).
[18] S. O. Mundt-Petersen, L. E. Harderup, Validation of a 1D transient heat and moisture calculation tool under real conditions, in: R. Karney, A. Desjarlais (Eds.), Thermal Performance of Exterior Envelopes of Whole Buildings XII, Clearwater, Florida, USA, 2013, p.12.
[19] WTA- 6-2-01/E – Guideline: Simulation of Heat and Moisture Transfer specifies hygrothermal simulations as an alternative to the „Glaser-method.
[20] Z. Pavlík, R. Černý, “Hygrothermal performance study of an innovative interior thermal insulation system”, Applied Thermal Engineering, vo. 29, pp. 1941-1946, 2010.