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Mould resistance design (MRD) model for evaluation of risk for microbial growth under varying climate conditions

Thelandersson, Sven LU and Isaksson, Tord LU (2013) In Building and Environment 65. p.18-25
Abstract
The risk for microbial growth depends on the microclimatic conditions at material surfaces. In the building envelope the microclimate will vary significantly with time. Whether microbial growth will occur or not, depends on humidity, temperature, duration of exposure and type of material (substrate). A limit state for onset of mould growth is here defined as a prescribed level observed by microscopy (40 x) in laboratory tests. In this paper, a mould resistance design (MRD) model is proposed by which onset of growth can be predicted for an arbitrary climate history of combined relative humidity empty set and temperature T. The model is calibrated and verified against a comprehensive set of new experimental data describing mould development... (More)
The risk for microbial growth depends on the microclimatic conditions at material surfaces. In the building envelope the microclimate will vary significantly with time. Whether microbial growth will occur or not, depends on humidity, temperature, duration of exposure and type of material (substrate). A limit state for onset of mould growth is here defined as a prescribed level observed by microscopy (40 x) in laboratory tests. In this paper, a mould resistance design (MRD) model is proposed by which onset of growth can be predicted for an arbitrary climate history of combined relative humidity empty set and temperature T. The model is calibrated and verified against a comprehensive set of new experimental data describing mould development on wood specimens (spruce and pine) as a function of exposure of relative humidity and temperature and material and surface characteristics. The exposure in the tests comprised both steady and time-variable conditions. Application of the MRD-model is demonstrated by assessment of mould risk based on results from simulations of an external wall design with hygro-thermal computer software (WUFI). The results show that a generally applicable, quantitative model together with building physics software can be used as a powerful tool for moisture safety design in practice. The model is designed to facilitate continuous improvement by further laboratory testing of various materials under specified climate conditions. The MRD-model is controlled by a basic parameter in the form of a critical dose D-crit, which depends on the substrate or material surface on which growth may take place. (c) 2013 Elsevier Ltd. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Mould growth, Limit state, Dose-response, Relative humidity, Temperature, Varying climate
in
Building and Environment
volume
65
pages
18 - 25
publisher
Elsevier
external identifiers
  • wos:000320349300002
  • scopus:84876697163
ISSN
1873-684X
DOI
10.1016/j.buildenv.2013.03.016
language
English
LU publication?
yes
id
16edbb4c-77d6-4dd6-b322-605ed9c71e30 (old id 3975886)
date added to LUP
2013-08-22 15:43:49
date last changed
2019-05-28 01:59:55
@article{16edbb4c-77d6-4dd6-b322-605ed9c71e30,
  abstract     = {The risk for microbial growth depends on the microclimatic conditions at material surfaces. In the building envelope the microclimate will vary significantly with time. Whether microbial growth will occur or not, depends on humidity, temperature, duration of exposure and type of material (substrate). A limit state for onset of mould growth is here defined as a prescribed level observed by microscopy (40 x) in laboratory tests. In this paper, a mould resistance design (MRD) model is proposed by which onset of growth can be predicted for an arbitrary climate history of combined relative humidity empty set and temperature T. The model is calibrated and verified against a comprehensive set of new experimental data describing mould development on wood specimens (spruce and pine) as a function of exposure of relative humidity and temperature and material and surface characteristics. The exposure in the tests comprised both steady and time-variable conditions. Application of the MRD-model is demonstrated by assessment of mould risk based on results from simulations of an external wall design with hygro-thermal computer software (WUFI). The results show that a generally applicable, quantitative model together with building physics software can be used as a powerful tool for moisture safety design in practice. The model is designed to facilitate continuous improvement by further laboratory testing of various materials under specified climate conditions. The MRD-model is controlled by a basic parameter in the form of a critical dose D-crit, which depends on the substrate or material surface on which growth may take place. (c) 2013 Elsevier Ltd. All rights reserved.},
  author       = {Thelandersson, Sven and Isaksson, Tord},
  issn         = {1873-684X},
  keyword      = {Mould growth,Limit state,Dose-response,Relative humidity,Temperature,Varying climate},
  language     = {eng},
  pages        = {18--25},
  publisher    = {Elsevier},
  series       = {Building and Environment},
  title        = {Mould resistance design (MRD) model for evaluation of risk for microbial growth under varying climate conditions},
  url          = {http://dx.doi.org/10.1016/j.buildenv.2013.03.016},
  volume       = {65},
  year         = {2013},
}