Validation of critical moisture conditions for mould growth on building materials

Abstract Materials that are stored or used in damp conditions may be subject to mould growth. However, all materials are not equally susceptible; for each specific material, there is a critical moisture level for mould growth. If this is exceeded, there is a risk that mould fungi will develop on the material. This level can be determined in accelerated laboratory tests, at constant temperatures and relative humidity (RH) favourable to mould growth. Within a building however, these parameters are expected to vary from one part of the construction to another, and are seldom constant; there is fluctuation in temperature and RH due to seasonal or shorter-term variations. In this study, test pieces of the same materials tested in a laboratory environment were placed in three outdoor ventilated crawl spaces and three outdoor ventilated attics, where the temperature and RH varied, and mould growth on the test pieces was studied over 2.5 years. Material-specific mould growth curves were produced based on critical moisture levels, as determined in laboratory experiments under constant temperature and RH. When the actual conditions of RH and temperature exceeded these curves, there was mould growth on the test pieces if the time was sufficiently long. The conclusion from the study is that although conditions in laboratory studies are simplified and accelerated, the results serve well to indicate mould growth within a building construction.

[1]  Ocg Olaf Adan,et al.  On the fungal defacement of interior finishes , 1994 .

[2]  A. F. Bravery,et al.  The moisture requirements of moulds isolated from domestic dwellings , 1989 .

[3]  Karin Foarde,et al.  Assessment of fungal (Penicillium chrysogenum) growth on three HVAC duct materials , 1996 .

[4]  G. Holm,et al.  Growth of moulds on building materials under different humidities , 2000 .

[5]  H. Viitanen,et al.  Mould growth on wood under fluctuating humidity conditions , 1994 .

[6]  Eva Frühwald,et al.  Image analysis study of mould susceptibility of spruce and larch wood dried or heat-treated at different temperatures , 2008 .

[7]  Gunilla Bok,et al.  Mass occurrence of Penicillium corylophilum in crawl spaces, south Sweden , 2009 .

[8]  Naresh Magan,et al.  Effect of water activity, temperature and substrate on interactions between field and storage fungi , 1984 .

[9]  G Blomquist,et al.  Volatile metabolites produced by two fungal species cultivated on building materials. , 1996, The Annals of occupational hygiene.

[10]  David Park,et al.  Phylloplane fungi: Tolerance of hyphal tips to drying , 1982 .

[11]  S. T. Hill,et al.  Influence of temperature and water activity on germination and growth of Aspergillus restrictus and A. versicolor , 1982 .

[12]  N. Poussereau,et al.  Impact of paint and wall-paper on mould growth on plasterboards and aluminum , 2010 .

[13]  D. Smorgon,et al.  Investigation of Capacitive-Based Relative Humidity Sensors and Their Stability at High Temperature , 2008 .

[14]  Frank Devlieghere,et al.  Standardisation of methods for assessing mould germination: a workshop report. , 2006, International journal of food microbiology.

[15]  Marc Stevens,et al.  Assessment of blue-stain resistance according to the EN 152 and a reverse test method using visual and computer-aided techniques , 2006 .

[16]  Anne Hyvärinen,et al.  Fungi and actinobacteria in moisture-damaged building materials — concentrations and diversity , 2002 .

[17]  Pernilla Johansson,et al.  Microbiological growth on building materials - critical moisture levels. State of the art , 2005 .

[18]  S. Block,et al.  Humidity requirements for mold growth. , 1953, Applied microbiology.

[19]  V. Sanchis,et al.  Water activity and temperature effects on germination and growth of Eurotium amstelodami, E. chevalieri and E. herbariorum isolates from bakery products , 1999, Journal of applied microbiology.

[20]  Joseph Andrew Clarke,et al.  Development of a Computer Programme for the Prediction and Control of Mould Growth in Buildings Using the ESP-r Modelling System , 1997 .

[22]  Q. Wang.  Wood-based boards - response to attack by mould and stain fungi , 1992 .

[23]  David Kilcast,et al.  The stability and shelf-life of food , 2000 .

[24]  Anne Hyvärinen,et al.  Quantitative PCR analysis of fungi and bacteria in building materials and comparison to culture-based analysis. , 2008, Journal of environmental monitoring : JEM.

[25]  K. Nielsen,et al.  Mould growth on building materials under low water activities: Influence of humidity and temperature on fungal growth and secondary metabolism , 2004 .

[26]  Naresh Magan,et al.  Effect of temperature and pH on water relations of field and storage fungi , 1984 .

[27]  Mieke Uyttendaele,et al.  Wageningen Academic Publishers , 2005 .

[28]  Hannu Viitanen,et al.  The response of building materials to the mould exposure at different humidity and temperature conditions , 2000 .

[29]  Pau Klein,et al.  San Francisco, California , 2007 .

[30]  Christine C. Gaylarde,et al.  Susceptibility of phosphogypsum to fungal growth and the effect of various biocides , 2002 .

[31]  Angela Sasic Kalagasidis,et al.  Mold Growth Control in Cold Attics through Adaptive Ventilation: Validation by Field Measurements , 2010 .

[32]  Guk-Rwang Won.  American Society for Testing and Materials , 1987 .

[33]  Robert A. Samson,et al.  Microorganisms in Home and Indoor Work Environments : Diversity, Health Impacts, Investigation and Control , 2001 .

[34]  Neil J. Rowan,et al.  Prediction of Toxigenic Fungal Growth in Buildings by Using a Novel Modelling System , 1999, Applied and Environmental Microbiology.

[35]  Pentti Kalliokoski,et al.  Fungal growth and survival in building materials under fluctuating moisture and temperature conditions , 2000 .

[36]  Pentti Kalliokoski,et al.  Occurrence and moisture requirements of microbial growth in building materials , 1992 .

[37]  M.Y. Menetrez,et al.  Growth Response of Stachybotrys Chartarum to Moisture Variation on Common Building Materials , 2004 .

[38]  Klaus Sedlbauer,et al.  Prediction of Mould Growth by Hygrothermal Calculation , 2002 .

[39]  C. Blackburn,et al.  3 – Modelling shelf-life , 2000 .

[40]  E. Kristiansson,et al.  A software pipeline for processing and identification of fungal ITS sequences , 2009, Source Code for Biology and Medicine.

[41]  Klaus Breuer,et al.  Mould resistance assessment of building materials – Material specific isopleth-systems for practical application , 2008 .

[42]  J. Lacey,et al.  Micro-organisms in stored grains: their enumeration and significance. , 1980 .

[43]  G. Ayerst,et al.  The effects of moisture and temperature on growth and spore germination in some fungi. , 1969 .