Conceptual Reference Database for Building Envelope Research Prev
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Related Concept
  • envelope performance
  • moisture in buildings
  • interstial condensation
  • windows, doors, fenestration



  • Related Articles
  • hidden: Concealed Condensation
  • condensation moisture as cause of moisture built-up in building envelope
  • condensation risk prediction by statistical risk simulation method in wall
  • construction moisture as cause of initial moisture trapped in wall
  • calculate: Glaser method, moisture profile method, dewpoint method
  • IEA Annex 14 Condensation and Energy
  • surface humidity criterion for design purposes by IEA Annex 14
  • Window Condensation

  • Concept:

    condensation and evaporation

    "The physics of condensation within the building envelope is quite complex and quantification of the phenomenon using mathematical computer models is the subject of some research today. The basic factors which affect the process have been known for some time and include but are not restricted to the following: indoor and outdoor temperatures, material properties such as air and vapour permeability, building envelope construction details, indoor relative humidity and indoor/outdoor air pressure differences. Condensation on or within the building envelope occurs when water vapour is transported to a location that is at or below the dewpoint temperature. Early researchers believed that the primary driving force in this transport was diffusion, a process dependent on vapour concentration differences and materials¡¯ resistance to vapour flow. This idea spawned the use of a ¡®vapour barrier¡¯ in the building envelope. Researchers now realize that while vapour diffusion can be a factor in some situations, the major reason for the amount of condensation in the construction of walls during the colder seasons is the outbound mass flow of moisture-laden air through the building envelope due to air leakage.

    There are three separate air pressure loads across the building envelope which cause air leakage. Wind, stack or chimney effect and mechanical pressurization have been documented in papers and the Canadian Building Digests produced by the National Research Council of Canada (NRC). William Rose provided an excellent summary of the history of condensation problems and ventilation requirements in attics in a paper presented to Thermal Envelope VI Conference (Rose 1995). Problems still may occur in some buildings having high relative humidity where even a small amount of air could result in moisture being transported into the building envelope construction. Older buildings where the interior environment is changed to provide humidity may also experience problems they never had. .."




    Web Links (3): Notes
      This link was checked on Dec. 2006CBD
      "240 of the 250 Canadian Building Digests published between 1960 and 1990 by NRC's Institute for Research in Construction. The topics reflect the diversity of the industry and cover virtually every aspect of design and construction in Canada."

      This link was checked on Dec. 2006Detec Systems - monitoring of hidden moisture in envelope of buildigns
      Detec Systems provides automated, cost effective monitoring of buildings to detect and locate moisture intrusions and internal flooding. This unique service protects property owners against the destructive effects of hidden water within the envelope

      This link was broken when checked on Dec. 2006IEA Annex 14: Condensation and Energy
      "provided architects, building owners, practitioners as well as researchers, with a better knowledge and understanding of the physical background of these phenomena (critical) conditions for mould growth, material characteristics related to the problems, it has also provided them with better computation models taking air, heat and moisture transfer into account in order to predict properly the phenomena of surface condensation and possible solutions to avoid it."

    Related References (35)
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    A critical review on equations employed for the calculation of the evaporation rate from free water surfaces , by Sartori, E., 2000
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    Analysis of the evaporation coefficient and the condensation coefficient of water, by Marek, R. and Straub, J., 2001
    IEA Annex 14
    Annex XIV: Condensation and Energy. Volume 2: Guidelines & Practice and Volume 3: Catalog of Material Properties, by IEA, 1990
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    CFD prediction of surface condensation on walls and its experimental validation, by Liu, J., Aizawa, H. and Yoshino, H., 2004
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    Comparative studies on the water evaporation rate from a wetted surface and that from a free water surface, by Tang, R. and Etzion, Y., 2004
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    Computer simulation of window condensation potential, by McGowan, A. G., Wright, J. L., 1998
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    Condensation potential in high thermal performance walls -- cold winter climate, by Sherwood, G. E., 1983
    condensation
    Condensation potential in high thermal performance walls -- cold winter climate, by Sherwood, G. E., 1983
    prevention and solution
    Condensation problems in your house: prevention and solution, by Anderson, L. O. and G. E. Sherwood, 1974
    risk analysis
    Condensation risk assessment, by Janssens, A. and H. Hens, 1998
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    Definition of two-dimensional condensation via BEM, using the Glaser method approach, by Sim?es, Branco, B. and A. Tadeu, 2002
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    Design parameters used to avoid interstitial condensation for a range of climates, by Sanders, C. H., 1995
    condensation in wood-frame house
    Durability of energy-efficient wood-frame houses, by Smulski, S., 1999
    discussion
    Dynamic buffer zone - DBZ, by Makepeace, C.B., R. Ogle, and R. Nelson, 1999
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    Evaluation of available correlations for rate of evaporation from undisturbed water pools to quiet air , by Shah, M. M., 2002
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    Evaporation coefficient of water: a review, by Eames, I. W., Marr, N. J. and Sabir, H., 1997
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    Free and forced convection effects on evaporation, by Sill, B. L., 1983
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    Free evaporation into air of water from a free horizontal quiet surface, by Boelter, L. M. K., Gordon, H. S. and Griffin, J. R., 1946
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    Heat and moisture transport with internal condensation in a fibrous insulation slab with impermeable boundary, by Couvillion, R. J. and Hawisa, J. S., 1993
    mold and condensation
    Humidity and development of mold on internal surfaces of building walls, by Sato, N., Vittorino, F. and Brazolin, S., 2000
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    IEA Annex 14: Condensation and Energy, by Hens, H., 1992
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    Interfacial mass and heat transfer during evaporation. I. An experimental technique and some results with a clean water surface , by Navon, U. and Fenn, J. B., 1971
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    Interstitial condensation due to air leakage: a sensitivity analysis, by Hens, J. A. and H. Hens, 2003
    in thermal bridges for design criteria
    Moisture condensation in thermal bridges. Establishing design criteria, by Aroso, M., H., 1995
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    Novel method for measuring water evaporation into still air , by Pauker, M. T., Tang, D., Jeter, S. M. and Abdel-khalik, S. I., 1998
    exterior wall, field
    On-site exterior wall monitoring methods for air leakage, condensation and rain penetration control problems, by Quirouette, R., 1999
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    Reliable control of interstitial condensation in lightweight roof systems, calculation and assessment methods, by Janssens, A., 1998
    risk
    Risk of indoor condensation related to thermal insulation standards, by Ponterio, L., Rizzo, G., Rodono, G., Scaccianoce, G., 1999
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    Surface temperatures of window specimens: infrared thermography laboratory measurements, by Griffith, B.T., H. Goudey and D. Arasteh, 2002
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    The influence of various condensation phenomena on the indoor cooling by cold walls radiation technique: the case of quality of air, by Decamps, E., A., Royer, G., Queneudec, M. and J. R. Givri, 1995
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    The ratio of heat losses by conduction and by evaporation from any water surface, by Bowen, I. S., 1926
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    Use of statistics for prediction of risk for condensation in a wall construction cold walls radiation technique: the case of quality of air, by Nielsen, A., 1995
    in porous material
    Vapour condensation and moisture accumulation in porous building wall, by Wyrwa, J. and Marynowicz, A., 2002
    condensation in built house
    Ventilation, humidity, and condensation in manufactured houses during winter, by TenWolde, A., 1994
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    Voluntary test method for thermal transmittance and condensation resistance of windows, doors and glazed wall sections, by AAMA, 1998



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