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WATER PERMEATION IN BUILDING MATERIALS

Objective



One of the major causes of damage to buildings is the ingress of water or humidity. This project therefore examined the method for determining the water permeation in low-density building materials such as extruded polystyrene and agglomerated (vermiculite) particle board, that are commonly used for thermal insulation. All the laboratories used the same basic gravimetric technique in which the sample is sealed into the mouth of an impermeable "cup", containing either desiccant or a salt solution, which is then placed in an environmental chamber. A constant vapour pressure difference is maintained across the sample and the water vapour permeability of the material is calculated from the steady decrease, or increase, in the weight of the cup.

RESULTS

Excluding outliers, for which explanations could be postulated, the range of the measured water vapour permeabilities remained very large (+/- 15 % for the polystyrene and +/- 20 % for the particle board) despite the fact that the test conditions were rigidly defined. An improvement of the situation would appear to necessitate modifications to the currently used design of the apparatus.

Topic(s)

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Call for proposal

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Coordinator

Minist. de Obras Publicas y Urbanismo
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Participants (12)

Centre Experimental de Recherches et d'Etudes du Batiment et des Travaux Publics (CEBTP)
France
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Centre Scientifique et Technique du Bâtiment (CSTB)
France
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EOLAS
Ireland
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Forschungsinstitut für Wärmeschutz eV
Germany
Address
Lochhamer Schlag 4
82166 München-gräfelfing

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K.U.L.
Belgium
Address

Leuven

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Laboratorio Nacional de Engenheria Civil
Portugal
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Staatliche Materialprüfungsanstalt
Germany
Address
Pfaffenwaldring 32
70569 Stuttgart

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TNO - IBBC
Netherlands
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Techn. Univ. of Denmark
Denmark
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University of Lund
Sweden
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University of Strachlyde
United Kingdom
Address

Glasgow

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WTCB/CSTC
Belgium
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