A durability assessment system that links a advanced computer model for structural and hygrothermal analysis with damage functions is currently being developed. The computational system has different modules that calculate the different structural and hygrothermal responses of wall systems. Outputs of these modules are input to the module of damage function models to calculate damage, performance and service-life of building envelopes. Details of biological damage functions implemented in the damage funciton module of the IRC durability asssessment system are presented. The biological damage functions were obtained from experiments. These biological damage functions trace deterioration in wood materials subjected to hygrothermal loads that favor fungal growth. The drvelopements of the models are based on recent biological experimental data from the literature. Equations to calculate various parameters in the model are summarized and the necessary steps for proper implementation are described. As an example, the application of the developed system is demonstrated using exfiltration of warm and humid indoor air in a typical wood frame construction in the temperature climate of North America.

other

Nofal, M. Hygrothermal Damage of Building Materials and Components: State-of-the-Art Report on Studies of Hygrothermal Damage and Proposed Approach for Damage Assessments, Internal Report, Institute for Research in Construction, National Research Council Canada, 757, pp. 139, March 01, 1998

• durability: biodeterioration
• durability: building envelope
• fungi: growth and growth model : as biological damage function
• HAM: theory and modelling : integrated mold growth with HAM (not complete in this paper)

1. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
2. Criteria for unacceptable damage on wood systems
3. Criteria for unaccesseptable damage on wood systems
4. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
5. Durability assessments of wood-frame construction using the concept of damage-functions  

1. A comparison of empirical indoor relative humidity models with measured data
2. A logical extension of the ASTM Standard E96 to determine the dependence of water vapor transmission on relative humidity
3. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
4. A thermal and moisture transport property data base for common building and insulating materials (final report)
5. Application of gamma-ray spectroscopy for determination of moisture distribution in insulating materials
6. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
7. Building envelope design, Part 2: estimating field performance of thermal insulation
8. Criteria for unaccesseptable damage on wood systems
9. Determination of equilibrium moisture content of building materials: some practical difficulties
10. Durability assessments of wood-frame construction using the concept of damage-functions
11. Effect of exfiltration on the hygrothermal behaviour of a residential wall assembly: results from calculations and computer simulations
12. Final Report, IEA-Annex 24, Task 3: Material Properties
13. Indoor and outdoor weather analysis tool for hygrothermal modelling
14. Influence of material properties on the moisture response of an ideal stucco wall: results from hygrothermal simulation
15. In-Situ performance evaluation of exterior insulation basement systems (EIBS) - spray polyurethane foam: summary report
16. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
17. Modeling heat, air and moisture transport through building materials and components
18. Moisture buffering capacities of five North American building materials
19. Moisture diffusivity of building materials from water absorption measurements
20. Moisture transport coefficient of pine from gamma ray absorption measurements
21. Prediction of moisture response of wood frame walls using IRC's advanced hygrothermal model (hygIRC)
22. Protecting the long-term performance of building envelope components
23. Report from Task 4 of MEWS Project - Environmental Conditions, Final Report
24. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
25. Taking guess work out of placing air/vapor barriers
26. Three-dimensional analysis of thermal resistance of exterior basement insulation systems (EIBS)
27. Use of hygrothermal numerical modeling to identify optimal retrofit options for high-rise buildings
28. Vapor transport characteristics of mineral fiber insulation from heat flow meter measurements
29. Water vapor transmission and moisture accumulation in polyurethane and polyisocyanurate foams