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Stochastic building envelope modeling -- the influence of material properties

Salonvaara, M. Karagiozis, A., and Holm, A.
2001
Proceedings for Performance of Exterior Envelopes of Whole Buildings VIII: Integration of Building Envelopes, December 2-7, Clearwater Beach, Florida

Salonvaara, M. Karagiozis, A., and Holm, A., (2001), "Stochastic building envelope modeling -- the influence of material properties", Proceedings for Performance of Exterior Envelopes of Whole Buildings VIII: Integration of Building Envelopes, December 2-7, Clearwater Beach, Florida.
Abstract:
In building envelope systems, the transport and storage of moisture impacts the basic porous structure layout. In many materials, dimensional changes occur when moisture levels are high enough. Most building materials and their respective material properties also change as a function of time. To complicate matters further, materials from one production batch to another may have substantially different hygrothermal, mechanical, and chemical properties. Even when two exact building material specimens are manufactured, their installation in the same wall design by two different craft persons may not be the same. Workmanship differences vary not only nationally but also locally from person to person. Material properties and workmanship issues must be appropriately addressed in the hygrothermal design of building constructions. These effects can only be taken into account by the use of advanced stochastic hygrothermal models in order to predict the hygrothermal performances of building envelope systems for a wide range of potential conditions. In this paper, two hygrothermal models (WUFI-StOpStar and LATENITE VTT) are used and compared with both deterministic and stochastic solutions. A MONTE CARLO stochastic model (MC) was incorporated into each hygrothermal model, and the models were employed to investigate the effect of nonhomogeneous differences in material properties for a stucco clad wall system. In the first series of simulations, the variations implemented in the model were obtained by performing an extensive amount of laboratory measurements. In the second series of simulations, a parametric investigation was performed to examine the particular influence of the exterior sheathing board on the performance of the same stucco clad wall system. The use of stochastic modeling in the area of hygrothermal analysis is novel and provides better understanding of the performance of "real envelope systems." This is of particular use for building envelope performance assessment to determine what elements of the design are critical.
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Author Information and Other Publications Notes
Salonvaara, M. K.
     
Holm, A.
Gunnar Holm Department of Biotechnology, Technical University of Denmark, Building 221, DK-2800 Lyngby, Denmark.
  1. An educational hygrothermal model: WUFI-ORNL/IBP
  2. Combined effect of temperature and humidity of the detoriation process of insulation materials in ETICS
  3. Determination of moisture and salt content distributions by combining NMR and gamma ray measurements
  4. Drying of an AAC flat roof in different climates Computational sensitivity analysis versus material property measurements
  5. Moisture buffering effects of interior linings made from wood or wood based products
  6. Moisture-buffering effect - experimental investigations and validation
  7. Non-isothermal moisture transfer in porous building materials
  8. Position paper on material characterization and HAM model benchmarking
  9. Practical application of an uncertainty approach for hygrothermal building simulations--drying of an AAC flat roof
  10. Previous Experimental Studies and Field Measurements on Moisture Buffering by Indoor Surface Materials
  11. Simulation of indoor temperature and humidity conditions including hygrothermal interactions with the building envelope
  12. The hygrothermal behaviour of rooms: combining thermal building simulation and hygrothermal envelope calculation
  13. Two-dimensional transient heat and moisture simulations of rising damp with WUFI 2D
  14. Uncertainty approaches for hygrothermal building simulations - drying of an AAC flat roof in different climates
  15. Uncertainty of hygrothermal calculations  


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