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Convection through Light Weight Timber Constructions with Mineral Wool

Authors: J. Schmidt, O. Kornadt

Abstract:

The major part of light weight timber constructions consists of insulation. Mineral wool is the most commonly used insulation due to its cost efficiency and easy handling. The fiber orientation and porosity of this insulation material enables flowthrough. The air flow resistance is low. If leakage occurs in the insulated bay section, the convective flow may cause energy losses and infiltration of the exterior wall with moisture and particles. In particular the infiltrated moisture may lead to thermal bridges and growth of health endangering mould and mildew. In order to prevent this problem, different numerical calculation models have been developed. All models developed so far have a potential for completion. The implementation of the flow-through properties of mineral wool insulation may help to improve the existing models. Assuming that the real pressure difference between interior and exterior surface is larger than the prescribed pressure difference in the standard test procedure for mineral wool ISO 9053 / EN 29053, measurements were performed using the measurement setup for research on convective moisture transfer “MSRCMT". These measurements show, that structural inhomogeneities of mineral wool effect the permeability only at higher pressure differences, as applied in MSRCMT. Additional microscopic investigations show, that the location of a leak within the construction has a crucial influence on the air flow-through and the infiltration rate. The results clearly indicate that the empirical values for the acoustic resistance of mineral wool should not be used for the calculation of convective transfer mechanisms.

Keywords: Resistance, Convection, Permeability, leakage, infiltration, convective transfer, mineralwool

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1057663

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References:


[1] Borsch-Laaks R., "Das unterschätzte Tauwasser-Risiko. Dampf- Konvektion im Steildach," Die neue quadriga, vol. 2, pp. 17-22, 2000
[2] Borsch-Laaks R., "Risiko Dampfkonvektion. Wann gibt es wirklich Schäden?," Die neue quadriga, vol. 3, pp. 17-22, 2006
[3] Borsch-Laaks R., "Tauwassersch├ñden durch Luftströmung. Auf die richtige Verklebung kommt es an, " Die neue quadriga, vol. 3, pp. 32- 35, 2009
[4] Borsch-Laaks R., Radovic B. and Schwaner K., "Akute Einsturzgefahr! Ein Feuchteschaden bei einem flach geneigten Dach mit Begr├╝nung," Die neue quadriga, vol. 4, pp. 49-52, 2010
[5] Schulze H., "Feuchtebedingte Schäden an Wänden, Decken und Dächern in Holzbauart," Fraunhofer IRB Verlag, Stuttgart, 2011, ISBN / EAN 9783816784661
[6] MOLL bauökologische Produkte GmbH, "Sanierungsstudie," http://download.proclima.com/de/de_w_Bauphysik-Sanierungs- Studie.pdf, 11.02.2011
[7] Geißler A. and Hauser G., "Absch├ñtzung des Risikopotentials infolge konvektiven Feuchtigkeitstransport," Abschlussbericht AIF-Forschungsvorhaben 12764, Kassel, Universit├ñt, 07/2002
[8] Eicke-Hennig W. and Krönig U., "Wind- und Luftdichtigkeit bei geneigten D├ñchern. Wissenswertes ├╝ber die Luftdichtigkeit von D├ñchern," Energiesparinformationen, vol. 07, Hessisches Ministerium f├╝r Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, 04/2011, ISBN / EAN 9783892743033
[9] Hall M. and Hauser G., "In situ Quantifizierung von Leckagen bei Gebäuden in Holzbauart," AIF-Forschungsvorhaben Nr. 12611 N, Abschlussbericht, Kassel, Universität, 5/2003
[10] Hagentoft C.-E., Kalagasidis A. S., Adl-Zarrabi B., Roels S., Carmeliet J., Hens H., Grunewald J., Funk M., Becker R., Shamir D., Adan O., Brocken H., Kumaran K. and Djebbar R., "Assessment Method of Numerical Prediction Models for Combined Heat, Air and Moisture Transfer in Building Components. Benchmarks for One-dimensional Cases," Journal of Thermal Envelope and Building Science, 27nd ed., vol. 4, pp. 326-352, 4/2004
[11] Riesner K., "Nat├╝rliche Konvektion in losen Außenwandd├ñmmungen," Dissertation, Rostock, Universit├ñt Rostock, 03/2003
[12] Riesner K., "Vermeidungsstrategien f├╝r Tauwasser- und Schimmelpilzrisiken in Außenwandgefachen, verursacht durch nat├╝rliche Konvektion in der D├ñmmung," Abschlussbericht, Rostock, Universit├ñt Rostock, 2009
[13] Mattsson B., "Studies on Building Air Leakage - a transient pressurisation method, measurement and modelling," Dissertation, Göteborg, Chalmers university of technology, 06/2007
[14] Schmidt J. and Kornadt O., "Konvektiver Feuchtetransport durch Wände und Wandbauteile," http://www.uni-weimar.de/cms/fileadmin/ bauing/files/profes-suren/bauphysik/Poster/Plakat_Feuchtetransport.pdf, 03.01.2012
[15] Schmidt J. and Kornadt O., "Convective Moisture Transfer through Walls and Wall Components," In: Aquametry 2010 Incl. Feuchtetag 2010, Weimar, 10/2010, pp. 527-534
[16] Schmidt J. and Kornadt O., "Konvektiver Feuchtetransport durch Bauteilleckagen in Bestandsgebäuden," In: Nutzerorientierte Bausanierung, Weimar, 1nd ed., 09/2010, pp. 109-116, ISBN / EAN 9783860684214
[17] DIN 68800-2, "Holzschutz - Teil 2: Vorbeugende bauliche Maßnahmen im Hochbau," Beuth Verlag GmbH, Berlin, 11/2009
[18] Wahlgren P, "Overview and Literature Survey of Natural and Forced Convection in Attic Insulation," Journal of Building Physics, 30th ed., vol. 4, pp. 351-370, 04/2007
[19] Hazen A., "Some Physical Properties of Sands and Gravels with Special Reference to their Use in Filtration," 24th Annual Report, vol. 34, pp. S. 539-556, 1893
[20] Hölting B. and Coldewey W. G., "Hydrogeologie. Einf├╝hrung in die allgemeine und angewandte Hydrogeologie ; 90 Tabellen," Spektrum Akad. Verl., Heidelberg, 2009, ISBN / EAN 9783827417138
[21] ISO 9053, EN 29053, "Materialien f├╝r akustische Anwendungen. Bestimmung des Strömungswiderstandes," Beuth Verlag GmbH, Berlin, 05/1993
[22] Dyrb├©l S., "Heat Transfer in Rockwool-Modelling and Method of Measurements, Part 1: The Effect of Natural Convection on Heat Transfer in Fabrous Materials," Phd-Thesis, Lyngby, Technical University of Denmark, 1998
[23] Dyrb├©l S., Svendsen S. and Elmroth A., "Experimental Investigation of the Effect of Natural Convection on Heat Transfer in Mineral Wool," Journal of Building Physics, 26nd ed., vol. 2, pp. 153-164, 10/2002
[24] Woebcken W., Adam W., Becker G. W. and Braun D. "Kunststoff- Handbuch. Duroplaste," Hanser, M├╝nchen, 1988, ISBN / EAN 3446144188
[25] Knauf Insulation GmbH and Institut Bauen und Umwelt e. V., eds., "Umwelt-Produktdeklaration nach ISO 14025. Mineralwolle mit ECOSE Technology, 02/2011
[26] Saint-Gobain ISOVER G+H AG and Institut Bauen und Umwelt e. V., eds., "Umwelt-Produktdeklaration nach ISO 14025. Unkaschierte Glaswolle-Platten und Filze, 09/2008
[27] Fouad N. A., ed., "Bauphysik Kalender. Energetische Sanierung von Gebäuden," Ernst & Sohn, Berlin, 2010, ISBN / EAN 9783433029381
[28] EN 12086, "Wärmedämmstoffe für das Bauwesen. Bestimmung der Wasserdampfdurchlässigkeit," Beuth Verlag GmbH, Berlin, 08/1997
[29] EN 13162, "W├ñrmed├ñmmstoffe f├╝r Geb├ñude - Werkm├ñßig hergestellte Produkte aus Mineralwolle (MW) - Spezifikationen," Beuth Verlag GmbH, Berlin, 05/2010
[30] Bauhaus-Universität Weimar, Inventors: Schmidt J. and Kornadt O., "Verfahren und Untersuchungsvorrichtung zur Untersuchung eines konvektiven Feuchtetransports in einem Bauwerkelement," Patent: DE102010031141, Germany, 09.07.2010
[31] Fritzen K., Krämer F.-J. and Metzger P., "Holzrahmenbau. Bewährtes Hausbau-System," Bruder-Verlag, Karlsruhe, 2007, ISBN / EAN 3871041394
[32] Aflekt K., "Isolasjonsmaterialers permeabilitet," Rapport, Trondheim, University of Trondheim, 1975
[33] Quantachrome Corporation, ed., "Automatic Pycnometers. The Density Analysis of Powders, Foams and Bulk Solids, Odelzhausen, 2007
[34] Cosmulescu C., "Experimental procedure to evaluate air leakage through different building materials," Master of Applied Science, Montreal, Quebec, Concordia University, 1997
[35] Fachverband Luftdichtheit im Bauwesen e.V. (FLIB), "Gebäude- Luftdichtheit, " 07/2008, ISBN / EAN 9733000248696
[36] EN 13829, "Bestimmung der Luftdurchlässigkeit von Gebäuden, Differenzdruckverfahren," Beuth Verlag GmbH, Berlin, 02/2001