Indoor Environmental Quality Guidelines
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I.3 Moisture Control
Intent
Prevent exterior water intrusion, leakage from interior water sources, or other uncontrolled accumulation of water.
Required Performance Criteria
- Design the building envelope to resist moisture penetration. Since all buildings have potential for moisture penetration, and since Minnesota is a heating dominated climate, provide drainage planes to the exterior.
- During the coldest portion (99.5% cold temperature design value) of the heating season keep the indoor dew point below 35ºF(2ºC).
- Specify maximum moisture content of materials used in construction to assure that subsurface layers are dry enough to prevent moisture trapping by surface finish materials (Consult: Lstiburek and Carmody, 1993, Harriman et al., 2001)
Note: Other related and critical items for moisture control are covered under other sections:
- I.5 Thermal Comfort which includes criteria for relative humidity
- P.4 Design and Construction Commissioning, Construction Air Quality Management Plan which includes requirements for air quality pre-assessment and correction of moisture and air quality problems in existing buildings that may affect New Building Additions or Major Renovations work.
- P.5 Operations Commissioning which includes practices for detection and management of unintended accumulation or intrusion of water.
Compliance Tools and Resources
- Suggested resource: Lstiburek, J, and J Carmody (1993) Moisture Control Handbook, New York, Van Nostrand. (Can be purchase from a general on line bookstore such as Amazon.com)
- Suggested resource: Harriman, L. I., G. Brundrett, et al. (2001.) Humidity Control Design Guide for Commercial & Institutional Buildings. Atlanta, ASHRAE. (can be purchased at ASHRAE online Bookstore)
Related MSBG Documents
- B3 Guidelines Tracking Tool
- Appendix I-0 Suggested Implementation for all Indoor Environmental Quality Guidelines
Supplemental Resources
- For supplemental information for Item A consider Lstiburek and Carmody, 1993; Lstiburek, 2002, Lstiburek, 2006 listed below.
- For supplemental information for Item B consider Consult: Lstiburek (2002) listed below.
- ASHRAE 62.1-2007 requirements:
- ASHRAE 62.1-2007 - §5.9 Filtration requirements for HVAC ductwork upstream of all cooling coils and other devices with wetted surfaces
- ASHRAE 62.1-2007 - §5.11-5.14 Condensate management and maintenance of moisture conditions in ductwork.
- ASHRAE 62.1-2007 - §5.5 Requirements that ductwork be resistant to mold growth.
- ASHRAE 62.1-2007 - §5.10 & 5.15 Humidity control and pressure control in spaces that are mechanically cooled
- ASHRAE 62.1-2007 - Addendum a. §5.10 Dehumidification Systems.
- ASHRAE (2005). 62.1 User's Manual, ANSI/ ASHRAE 62.1-2007 Ventilation for Acceptable Indoor Air Quality. Atlanta, GA, ASHRAE.
- Lstiburek, J, and J Carmody (1993) Moisture Control Handbook, New York, Van Nostrand.
- Lstiburek, J. (2002.) "Moisture Control for Buildings." ASHRAE Journal 44(2): 36-41.
- Lstiburek, J. (2006) "Understanding Drainage Planes" ASHRAE Journal 48(2) 30-35
- Harriman, L. I., G. Brundrett, et al. (2001.) Humidity Control Design Guide for Commercial & Institutional Buildings. Atlanta, ASHRAE.
- California Occupational Safety and Health Standards Board, Title 8, Chapter 4, Article 9, Section 3362(g) "uncontrolled accumulation of water" (2002.)
- Horner, W. E., P. R. Morey, et al. (2001.) "How quickly must gypsum board and ceiling tile be dried to preclude mold growth after a water accident". Moisture, Microbes, and Health Effects: Indoor Air Quality and Moisture in Buildings, San Francisco, CA, IAQ 2001.
- Kosar, D. (2006). "Dehumidification system enhancements." ASHRAE Journal 48(2): 48-58.
- Wyon, D., L. Fang, et al. (2002.) "Limiting Criteria for Human Exposure to Low Humidity Indoors". Indoor Air 2002, Monterey, CA, Vol. 4, pp. 400-405.