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Building pressurisation can affect possibility of mould growth

Fazio, P., Ge, H., Rao, J. and Desmarais, G.
1999
IEQ Strategies, August, pp 8-13,
mould, building pressurisation, air flow, Moisture, condensation problems

Fazio, P., Ge, H., Rao, J. and Desmarais, G., (1999), "Building pressurisation can affect possibility of mould growth", IEQ Strategies, August, pp 8-13,.
Abstract:
Describes case studies which demonstrate the various ways that forced-air systems can significantly affect building pressures. In each case the authors were contacted to determine the cause of mould growth on interior drywall. In each case also, mould growth was determined to be caused by moisture accumulation in the drywall, primarily from the uncontrolled flow of outside air into the building envelope. The case studies concern: 1. Central exhaust system; 2. Building air chases used as a distribution system; 3. Leakage at guest room fan coil units. Concludes that moisture related damage in commercial buildings can result in millions of dollars in damage annually and can come from five possible sources of moisture: bulk moisture intrusion; internally generated moisture; vapour moisture diffusion; capillarity; air leakage. A primary cause of air leakage is depressurisation of the building by the HVAC system, although many HVAC designs have the opposite intent - to pressurise the building. Unfortunately current HVAC commissioning procedures are unable to accurately determine if the HVAC design intent has been accomplished. This is because current commissioning techniques are based on measurement of airflows at delivery and extraction points, such as a supply registers and exhaust grilles. Airflow measurements at these points alone cannot properly assess the performance of the HVAC system or its impact on the characteristics of a building because they fail to fully consider air distribution. The startup sequence of HVAC forced air systems is also a critical aspect of commissioning a building. An improper startup sequence will prevent a forced air system from performing according to the design intent. If this condition occurs during hot, humid weather, moisture accumulation and mildew can occur within several weeks.
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Author Information and Other Publications Notes
Fazio, P.
Paul Fazio, Professor of Building, Civil & Environmental Engineering, Concordia University, Montreal
  1. A limit state design (LSD) approach for comparing relative drying performance of wood-frame envelope systems with full-scale lab, A roadmap towards intelligent net zero- and positive-energy buildings,
  2. A new test method to determine the relative drying capacity of building envelope panels of various configurations
  3. A new testing method to evaluate the relative drying performance of different building envelope systems using water trays
  4. A quantitative study for the measurement of driving rain exposure in the Montr¨¦al region
  5. A review of research activities in energy efficiency in buildings in Canada
  6. Airtightness testing and air flow modeling of two and three-unit multifamily buildings
  7. Airtightness testing of two- and three-unit buildings with a single fan
  8. Approach for the simulation of wetting due to rain infiltration for building envelope testing
  9. Approach for urban driving rain index by using climatological data recorded at suburban meteorological station
  10. Behavior of wall assemblies with different wood sheathings wetted by simulated rain penetration
  11. Building Physics: 3rd International Conference in Building Physics
  12. Cavity pressure in rain screen walls
  13. Comparaison de m¨¦thodes de mesure de flux de chaleur pour sp¨¦cimens de grandes et moyennes dimensions
  14. Continuous folded plate structures under uniform load
  15. Creative case adaptation for building engineering design
  16. Design and construction of an environmental chamber facility
  17. Design Methodology of Solar Neighborhoods
  18. Development of experimental procedure to evaluate potential movement of mold spores from wall cavity to indoor environment
  19. Development of HAM tool for building envelope analysis
  20. Effect of capillarity on rainwater penetration in the building envelope
  21. Environmental chamber for investigation of building envelope performance
  22. Essai sur les toits plats isol¨¦s ¨¤ la fibre de cellulose
  23. Evaluation of radiance's genBSDF capability to assess solar bidirectional properties of complex fenestration systems
  24. Experimental evaluation of potential transport of mold spores from moldy studs in full-size wall assemblies
  25. Experimental setup for the study of air leakage patterns
  26. Experimental study of temperature distributions across two curtain wall systems
  27. Folded sandwich plate structures
  28. Identification and transport investigation of microbial volatile organic compounds in full-scale stud cavities
  29. IFC-based framework for evaluating total performance of building envelopes
  30. Impact of added insulation on air leakage patterns
  31. Impact of air leakage pattern on reinsulated walls
  32. In-cavity evaporation allowance--A drying capacity indicator for wood-frame wall system
  33. Influence of air space on multi-layered material water vapor permeability measurement
  34. Influence of facade geometry on weathering
  35. Integrated analysis of whole building heat, air and moisture transfer
  36. Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test hut: Part 1 - Experimental study
  37. Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test-hut: Part 2- CFD study
  38. Large scale testing of two flat roof assemblies insulated with cellulose
  39. Mapping of air leakage in exterior wall assemblies
  40. Measuring air leakage characteristics with flexible double air chambers
  41. Measuring air leakage of full-scale curtain wall sections using a non-rigid air-chamber method
  42. Methods for the assessment of moisture content of envelope assemblies
  43. Modeling of moisture behavior of wood planks in nonvented flat roofs
  44. Modelling of indoor air humidity: the dynamic behaviour within an enclosure
  45. Moisture buffering capacities of five North American building materials
  46. Moisture performance of leaky exterior walls with added insulation
  47. Nonlinear elastic analysis of panelized shear sandwich walls
  48. Numerical investigation of the influence of room factors on HAM transport in a full-scale experimental room
  49. Performance evaluation protocol for full-scale wood-frame building envelopes
  50. Potential of rain screen walls to prevent rain penetration: pressurized cavity principle
  51. Quantitative driving rain exposure on a vertical wall at various Canadian cities
  52. Rapport Final Projet Site Internet - L'enveloppe du batiment et l'efficacit¨¦ ¨¦nerg¨¦tique
  53. Review and framework for large-scale laboratory studies on wetting and drying of building envelopes
  54. Study of the reduced impact of thermal bridges in two sprayed-applied polyurethane wall assemblies
  55. Study on thermal performance of curtain walls using infrared thermography
  56. Test method to measure the relative capacity of wall panels to evacuate moisture from their stud cavity
  57. Testing of flat roofs insulated with cellulose fiber
  58. The dynamic modelling of air humidity behaviour in a multi-zone space
  59. Transfer of heat, moisture and air through metal curtain walls
  60. Transient model for coupled heat, air and moisture transfer through multilayered porous media
  61. Use of an environmental chamber to investigate large-scale envelope specimen hygrothermal performance  
Ge, H.
Ph.D, - 2002, Department of Building, Civil, and Environmental Engineering, Concordia University, Montreal
  1. Building Physics: 3rd International Conference in Building Physics
  2. Experimental study of temperature distributions across two curtain wall systems
  3. Measuring air leakage characteristics with flexible double air chambers
  4. Measuring air leakage of full-scale curtain wall sections using a non-rigid air-chamber method
  5. Study on overall thermal performance of metal curtain walls
  6. Study on thermal performance of curtain walls using infrared thermography
  7. Test method to measure the relative capacity of wall panels to evacuate moisture from their stud cavity
  8. Transfer of heat, moisture and air through metal curtain walls  
Rao, J.
Department of Building, Civil, and Environmental Engineering, Concordia University, Montreal
  1. A limit state design (LSD) approach for comparing relative drying performance of wood-frame envelope systems with full-scale lab, A roadmap towards intelligent net zero- and positive-energy buildings,
  2. A new test method to determine the relative drying capacity of building envelope panels of various configurations
  3. A new testing method to evaluate the relative drying performance of different building envelope systems using water trays
  4. Building Physics: 3rd International Conference in Building Physics
  5. Comparaison de m¨¦thodes de mesure de flux de chaleur pour sp¨¦cimens de grandes et moyennes dimensions
  6. Design and construction of an environmental chamber facility
  7. Development of experimental procedure to evaluate potential movement of mold spores from wall cavity to indoor environment
  8. Development of HAM tool for building envelope analysis
  9. Effect of capillarity on rainwater penetration in the building envelope
  10. Environmental chamber for investigation of building envelope performance
  11. Evaluation of radiance's genBSDF capability to assess solar bidirectional properties of complex fenestration systems
  12. Experimental evaluation of potential transport of mold spores from moldy studs in full-size wall assemblies
  13. Experimental study of temperature distributions across two curtain wall systems
  14. Identification and transport investigation of microbial volatile organic compounds in full-scale stud cavities
  15. In-cavity evaporation allowance--A drying capacity indicator for wood-frame wall system
  16. Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test hut: Part 1 - Experimental study
  17. Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test-hut: Part 2- CFD study
  18. Measuring air leakage characteristics with flexible double air chambers
  19. Measuring air leakage of full-scale curtain wall sections using a non-rigid air-chamber method
  20. Numerical investigation of the influence of room factors on HAM transport in a full-scale experimental room
  21. Review and framework for large-scale laboratory studies on wetting and drying of building envelopes
  22. Statistical analysis of microbial volatile organic compounds in an experimental project: identification and transport analysis
  23. Study of the reduced impact of thermal bridges in two sprayed-applied polyurethane wall assemblies
  24. Test method to measure the relative capacity of wall panels to evacuate moisture from their stud cavity
  25. Transfer of heat, moisture and air through metal curtain walls
  26. Use of an environmental chamber to investigate large-scale envelope specimen hygrothermal performance  
Desmarais, G.
Department of Building, Civil, and Environmental Engineering, Concordia University, Montreal
  1. Building Physics: 3rd International Conference in Building Physics
  2. Comparaison de m¨¦thodes de mesure de flux de chaleur pour sp¨¦cimens de grandes et moyennes dimensions
  3. Experimental setup for the study of air leakage patterns
  4. Final Report from Task 8 of MEWS Project (T8-03) - Hygrothermal Response of Exterior Wall Systems to Climate Loading: Methodology and Interpretation of Results for Stucco, EIFS, Masonry and Siding Clad Wood-Frame Walls
  5. Impact of added insulation on air leakage patterns
  6. Impact of added insulation on the hygrothermal performance of leaky exterior wall assemblies
  7. Impact of air leakage pattern on reinsulated walls
  8. Mapping of air leakage in exterior wall assemblies
  9. Moisture performance of leaky exterior walls with added insulation
  10. Report from Task 2 of MEWS Project - Description of 17 Large Sale Wall Specimens Built for Water Entry Investigation in IRC Dynamic Wall Testing Facility
  11. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
  12. Study of the reduced impact of thermal bridges in two sprayed-applied polyurethane wall assemblies  


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