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Ventilated rainscreen cladding: A study of the ventilation drying process

Falk, Jörgen LU and Sandin, Kenneth LU (2013) In Building and Environment 60. p.173-184
Abstract
The air exchange in rainscreen walls is expected to provide ventilation drying if excess moisture is absorbed in the wall construction. In an earlier paper, we presented a cavity airflow model and measurement based estimations of air change rates (ACH) in south-facing experimental walls. Here, focus is on the ventilation drying process and its practical implications. ACH in the experimental walls were calculated and converted into drying rates at different stages in the drying process. Furthermore, changes in the drying rates due to changes in the cavity design and in the outdoor climate were investigated. The significance of the drying rates was demonstrated in a case study. Findings showed that the cavity design is of major importance... (More)
The air exchange in rainscreen walls is expected to provide ventilation drying if excess moisture is absorbed in the wall construction. In an earlier paper, we presented a cavity airflow model and measurement based estimations of air change rates (ACH) in south-facing experimental walls. Here, focus is on the ventilation drying process and its practical implications. ACH in the experimental walls were calculated and converted into drying rates at different stages in the drying process. Furthermore, changes in the drying rates due to changes in the cavity design and in the outdoor climate were investigated. The significance of the drying rates was demonstrated in a case study. Findings showed that the cavity design is of major importance for the drying rate if the material adjacent to the cavity is wet over its entire extension. For such extreme cases, a light facade colour, vented horizontal battens and, in particular, a small cavity depth, are adverse factors for the drying rate. As the drying process proceeds and the moisture transport from the material to the cavity air becomes dependent on vapour diffusion, the drying rates for different cavity designs tend to be evened out. If the resistance to vapour flow in the material reaches high levels, a favourable outdoor climate is significantly more important than the cavity design to promote drying. Also for the case where the material adjacent to the cavity initially is only locally wet, findings showed that the cavity design is of minor importance for the drying time. (c) 2012 Elsevier Ltd. All rights reserved. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ventilated cavity, Air change rate, Ventilation drying rate, Cavity, moisture transport, Drying time
in
Building and Environment
volume
60
pages
173 - 184
publisher
Elsevier
external identifiers
  • wos:000314734800016
  • scopus:84871147744
ISSN
1873-684X
DOI
10.1016/j.buildenv.2012.11.015
language
English
LU publication?
yes
id
994d6f75-d64f-4fd1-b921-dde028ca8363 (old id 3580868)
date added to LUP
2016-04-01 12:52:20
date last changed
2022-01-27 08:01:37
@article{994d6f75-d64f-4fd1-b921-dde028ca8363,
  abstract     = {{The air exchange in rainscreen walls is expected to provide ventilation drying if excess moisture is absorbed in the wall construction. In an earlier paper, we presented a cavity airflow model and measurement based estimations of air change rates (ACH) in south-facing experimental walls. Here, focus is on the ventilation drying process and its practical implications. ACH in the experimental walls were calculated and converted into drying rates at different stages in the drying process. Furthermore, changes in the drying rates due to changes in the cavity design and in the outdoor climate were investigated. The significance of the drying rates was demonstrated in a case study. Findings showed that the cavity design is of major importance for the drying rate if the material adjacent to the cavity is wet over its entire extension. For such extreme cases, a light facade colour, vented horizontal battens and, in particular, a small cavity depth, are adverse factors for the drying rate. As the drying process proceeds and the moisture transport from the material to the cavity air becomes dependent on vapour diffusion, the drying rates for different cavity designs tend to be evened out. If the resistance to vapour flow in the material reaches high levels, a favourable outdoor climate is significantly more important than the cavity design to promote drying. Also for the case where the material adjacent to the cavity initially is only locally wet, findings showed that the cavity design is of minor importance for the drying time. (c) 2012 Elsevier Ltd. All rights reserved.}},
  author       = {{Falk, Jörgen and Sandin, Kenneth}},
  issn         = {{1873-684X}},
  keywords     = {{Ventilated cavity; Air change rate; Ventilation drying rate; Cavity; moisture transport; Drying time}},
  language     = {{eng}},
  pages        = {{173--184}},
  publisher    = {{Elsevier}},
  series       = {{Building and Environment}},
  title        = {{Ventilated rainscreen cladding: A study of the ventilation drying process}},
  url          = {{http://dx.doi.org/10.1016/j.buildenv.2012.11.015}},
  doi          = {{10.1016/j.buildenv.2012.11.015}},
  volume       = {{60}},
  year         = {{2013}},
}