Influence of Moisture Buffering Effects on the Risk of Mould Growth Martin Krus
Background Beside room temperature and and radiative balance the relative humidity is decisive for the comfort in a room relative humidity [%] comfortable uncomfortable humid still comfortable uncomfortable dry Air temperature [ C] Question: Does moisture buffering also effect the risk of mould growth in spite of not changing the dayly mean values of R.H.? Seite 2
Experimental investigations est facilities Two identical testrooms View from the South Seite 3
Measured courses of the climate Seite 4
Measured courses of the climate 8 Painted Gypsum Plaster 14. February. 16.3. March 8 Painted Gypsumboard 7 7 6 6 relative Humidity [%] 4 relative Humidity [%] 4 3 3 2 2 1 12/2/ 17/2/ 22/2/ 27/2/ 4/3/ 9/3/ 14/3/ 1 mean R.H.: 34% mean R.H.: 34% 19/3/ 12/2/ 17/2/ 22/2/ 27/2/ 4/3/ 9/3/ 14/3/ 19/3/ Seite 5 24/3/
Measured courses of the climate 8 Spruce Panels 16. January - 9. February 7 relative Humidity [%] 6 4 3 Problem of all measured couses: to short to assess the risk of mould repetition of these courses up to a period of three month 2 1 14/1/23 19/1/23 24/1/23 mean R.H.: 4% 29/1/23 3/2/23 8/2/23 13/2/23 The calculation was performed with this inner climates for a corner of an old non insulated wall Seite 6
Biohygrothermal Model Substrate Groups II biological adverse recycable materials I biological recycable materials optimum cultures mediu 1 Relative humidity [%] Temperature [ C] Seite 7
Painted Gypsum Plaster 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class II Seite 8
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 2: ; Datum: 21/1/26 17:13:11 Painted Gypsumboard 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class II Seite 9
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 2: ; Datum: 21/1/26 17:13:11 Painted Gypsumboard 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class I Seite 1
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 3: ; Datum: 21/1/26 17:37:52 Spruce Panels 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Despite of a higher mean R.H.!! Substrate Class I Seite 11
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 3: ; Datum: 21/1/26 17:37:52 Spruce Panels 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class Seite 12
Problem: The courses are not really comparable because of different ambient conditions. Investigations with a standard annually course of an inner climate with normal moisture load (dayly ( mean values) 1 Innenluft a) without diurnal variations b) with twice diurnal l variations c) with twice diurnal variations (+- 1% R.H.) (+- 15% R.H.) 1 1 Innenluft 6 12 18 24 Innenluft Innenluft 1 6.7 121.4 182.1 242.8 33.5 364.2 6.7 121.4 182.1 242.8 33.5 364.2 6.7 121.4 182.1 242.8 33.5 364.2 Seite 13
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 4: ; Datum: 21/1/26 18:6:3 normal inner climate 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class Seite 14
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 6: innen normal +-1%; Datum: 21/1/26 18:43:12 normal inner climate +-1% 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 15 3 45 6 9 Substrate Class Seite 15
UFI Pro 4. IBP; Projekt: Lyon.W 4P; Variante 6: innen normal +-1%; Datum: 21/1/26 18:48:15 normal inner climate +-15% 1 R.H. on the inner Surface Monitorpos. 2 (Innenoberfläche) Relative Feuchte [%] 6.7 121.4 182.1 242.8 33.5 364.2 Substrate Class I Seite 16
Conclusions The moisture buffering reduces the risk of mould growth remarably Dayly mean values for the inner climate are not sufficient for assessing the risk of mould growth Seite 17