Evaluation of Hygrothermal Simulation Results

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Evaluation of Hygrothermal Simulation Results
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Contents Hygrothermal analysis Critical
moisture conditions Corrosion Microbial
growth Conclusions
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Hygrothermal analysis
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Hygrothermal analysis
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Hygrothermal analysis
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Hygrothermal analysis
WUFI-simulations of concrete walls with and
without exterior insulation (west orientation) in
Europes South (Lisbon)
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Contents Hygrothermal analysis Critical
moisture conditions Corrosion Microbial
growth Conclusions
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Critical moisture conditions
Attic insulation under German climate conditions
Inclination 50 Orientation North Indoor
climate 20-22C, 40-60 RH Performace
evaluation of vapour retarder
ceramic tiles lathing counter-lathing bituminous
felt sheathing fiber glass insulation between
rafters vapor retarder gypsum board
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Critical moisture conditions

• Diffusion resistance of vapour retarder
• sd 5 m (0.7 perm)

Total Water Content kg/m²
Problem moisture accumulation
Time a
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Critical moisture conditions

• Diffusion resistance of vapour retarder
• sd 0.5 m (7 perm)

Problem excessive condensation (DIN limit 1.0
kg/m²)
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Critical moisture conditions

• Diffusion resistance of vapour retarder
• sd 2 m (1.7 perm)

No problem ?
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Critical moisture conditions
Wooden sheathing - MC gt 20 M.- ? gt 10C
(50F)
Sheatthing Moisture M.-
Problem risk of sheating degradation (rot)
Time a
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Critical moisture conditions

• Diffusion resistance of vapour retarder
• humidity controlled sd 0.1 4.0 m
  (0.8 - 36 perm)

Sheatthing Moisture M.-
Acceptable performance
Time a
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Contents Hygrothermal analysis Critical
moisture conditions Corrosion Microbial
growth Conclusions
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Corrosion
Corrosion of concrete wall elements after
carbonation of exterior surface layer
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Corrosion
WUFI simulation over several years
Concrete 80 kg/m³ (8 vol.-) EMC at 95 r.F.
Water content kg/m³
Cross-section cm
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Corrosion
Marquardt steel corrosion in carbonated concrete
stops below 80 RH
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Corrosion
WUFI Simulation Drying of concrete rain
screen under German climate conditions after
retrofitting the walls with EIFS (ETICS)
EIFS (EPS)
RH at Reinforcing Steel
EIFS (MW)
Corrosion discontinued 6 months (MW) res. 2 years
(EPS) after application of EIFS (ETICS)
Insulation
Insulation
Time a
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Corrosion
Field tests by Marquardt (TU Berlin)
steel bars behind cladding
steel bars behind insulation
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Corrosion
Determination of the hygrothermal conditions in
exposed concrete structures with and without
exterior insulation in Southern Europe
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Corrosion
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Corrosion
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Contents Hygrothermal analysis Critical
moisture conditions Corrosion Microbial
growth Conclusions
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Microbial growth
Substrate groups 0 optimum substrate (biologica
l full medium) I biodegradable
substrates (wood, wall paper, ...) II non
biodegradable substrates (mineral building
materials)
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Microbial growth
WUFI Simulation stud wall with natural fiber
and glass fiber insulation
Monitor A B C
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Microbial growth
Natural Fiber Glass Fiber
Monitor
WUFI Simulation coinciding temperature and RH
conditions at monitor positions
A
Relative Humidity
B
More detailed evaluation requires dynamic mould
growth model
C
Temperature C
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Conclusions

• Heat losses due to conduction and latent effects
  can be determined
• Moisture accumulation indicates damage risk
• Moisture content of wood or wood based materials
  should not exceed 20 by mass if temperatures gt
  10 C.
• To avoid corrosion in carbonated steel concrete
  RH lt 80
• Microbial growth may start below 80 RH if temp.
  gt 12 C.
• Some results on frost damage risk are available
• To assess ageing effects more research is
  necessary
• For total energy consumption refer to WUFI

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Evaluation of Hygrothermal Simulation Results