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  1. #1
    Join Date
    Jul 2005
    Location
    Phoenix, AZ
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    266

    Confused ASHRAE Humidity Standards

    Does anyone know if the ASHRAE manuals have the standards for humidity control for apartment multifamily complexes? Could someone direct me in the right direction?

  2. #2
    http://www.ashrae.org/technology/page/336

    This lists ASHRAE 55 (humidity level should be below 65% RH... duh) and ASHRAE 62.2 concerning ventilation. Does that answer your question?

  3. #3
    Join Date
    Jul 2005
    Location
    Phoenix, AZ
    Posts
    266

    Thumbs up ASHRAE Manuals

    Thanks for the help. I was looking for the standards number. Judt wanted to get something in writing.

  4. #4
    Join Date
    Mar 2005
    Posts
    997
    20% - 60%

  5. #5
    Join Date
    May 2008
    Location
    brooklyn ny
    Posts
    103
    THE ONLY WAY IS CHECK ASHRAE WEBSITE FOR THAT INFO GEOGLE IT

  6. #6
    Join Date
    Jul 2011
    Location
    East coast USA
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    1,002
    Quote Originally Posted by phxhvac View Post
    Does anyone know if the ASHRAE manuals have the standards for humidity control for apartment multifamily complexes? Could someone direct me in the right direction?
    http://epb.lbl.gov/publications/lbnl-54331.pdf


    Have fun, this might help. but don't get to caught up in the standards they can be daunting to make sense out of them.

  7. #7
    Join Date
    Oct 2009
    Location
    Murfreesboro, TN
    Posts
    108
    Are you asking if maintaining a humidity level below 65% will prevent mold growing on walls, etc.? Please don't give the owner a false sense of security. There can be leaks around windows, under sinks, under outside sliding doors, and around bad roof flashing that can keep a surface or wall wet enough to grow a patch of fungus. The interior humidity level can still be under 65% rh during all of this. If a food source stays wet for an extended period you will have a fungi family form.

  8. #8
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,646
    Unfortunately, mold grows when any surface approaches saturation. Cool surfaces will be musty with 65%RH. An example is a carpet on a concrete slab. With cool slab, the %RH between the slab and carpet approach 100%RH. The result is a musty odor that indicates mold growth. Also dust mites grow with +60^RH.
    <50%RH assures mold and dust mite are controlled in most homes. During winter weather <35%RH may be required to avoid condensation on the cold surface of the exterior surfaces. This is not stated in ASHRAE standards.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  9. #9
    Join Date
    Apr 2012
    Location
    Millsboro, DE
    Posts
    100
    PHX: You want ASHRAE 55, the Standard for human comfort. ASHRAE 62 covers air quality.

  10. #10
    Join Date
    May 2008
    Location
    Cebu City, Philippines
    Posts
    41
    Use Ducted FCU, measure %RH coming out. If beyond control, say %60+. Process air through pre-cooling, so that from %60+ it would reduce to %50 or less.

    regards,
    moriel

  11. #11
    Join Date
    Jun 2002
    Location
    Dacula, GA
    Posts
    12,955
    Quote Originally Posted by drk View Post
    20% - 60%
    20% is too low. Don't let it drop below 30% to prevent static shock especially when walking across carpet and touching a door handle. 65% is the max you should ever have. Mold growth takes off above there. Thank you very much
    "I could have ended the war in a month. I could have made North Vietnam look like a mud puddle."
    "I have little interest in streamlining government or in making it more efficient, for I mean to reduce its size. I do not undertake to promote welfare, for I propose to extend freedom. My aim is not to pass laws, but to repeal them. It is not to inaugurate new programs, but to cancel old ones that do violence to the Constitution."
    Barry Goldwater

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