Results 1 to 4 of 4
  1. #1
    Join Date
    Sep 2008
    Location
    so so, California
    Posts
    1,769

    Default Return air question

    I was reading this section and wanted to get some of your opinions on this section specifically the last exception. Am I correct to interpret this as saying that those areas listed "are" allowed?
    Or is it saying that these areas are not allowed simply by exclusion?
    Thanks..


    2010 CMC 311.3 Prohibited Source.
    Outside or return air for a heating

    or cooling air system shall not be taken from the following
    locations:
    (1) Closer than ten (10) feet (3,048 mm) from an appliance
    vent outlet, a vent opening of a plumbing drainage system,
    or the discharge outlet of an exhaust fan, unless the outlet
    is three (3) feet (914 mm) above the outside-air inlet.
    (2) Where it is less than ten (10) feet above the surface of
    any abutting public way, driveway, sidewalk, street, alley
    or driveway.
    (3) A hazardous or insanitary location or a refrigeration
    machinery room as defined in this code.
    (4) From an area, the volume of which is less than 25 percent
    of the entire volume served by such system, unless there
    is a permanent opening to an area the volume of which is
    equal to 25 percent of the entire volume served.
    Exception: Such openings when used for a heating or

    cooling air system in a dwelling unit shall be permitted

    to be reduced to not less than 50 percent of the required
    area, provided the balance of the required return air is
    taken from a room or hall having not less than three (3)

    doors leading to other rooms served by the furnace.
    (5) A closet, bathroom, toilet room, or kitchen.
    (6) From rooms or spaces containing a fuel-burning appliance
    therein.Where such room or space serves as source
    of return air.
    Exceptions:
    (1) This shall not apply to fireplaces, fireplace appliance,
    residential cooking appliance, direct vent
    appliance, enclosed furnaces, and domestic-type
    clothes dryers installed within the room or space.


    Similar Threads:
    Inspection Referral SOC
    The MAZZA INSPECTION GROUP
    www.mazzainspections.com
    Level III Thermo-picture-taker-er...er

  2. #2
    Join Date
    Mar 2007
    Location
    Columbus GA
    Posts
    3,746

    Default Re: Return air question

    It's easy to follow once you know who's on first.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  3. #3
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Return air question

    Quote Originally Posted by Marc M View Post
    I was reading this section and wanted to get some of your opinions on this section specifically the last exception. Am I correct to interpret this as saying that those areas listed "are" allowed?
    Or is it saying that these areas are not allowed simply by exclusion?
    Thanks..


    2010 CMC 311.3 Prohibited Source.
    Outside or return air for a heating

    or cooling air system shall not be taken from the following
    locations:
    (1) Closer than ten (10) feet (3,048 mm) from an appliance
    vent outlet, a vent opening of a plumbing drainage system,
    or the discharge outlet of an exhaust fan, unless the outlet
    is three (3) feet (914 mm) above the outside-air inlet.
    (2) Where it is less than ten (10) feet above the surface of
    any abutting public way, driveway, sidewalk, street, alley
    or driveway.
    (3) A hazardous or insanitary location or a refrigeration
    machinery room as defined in this code.
    (4) From an area, the volume of which is less than 25 percent
    of the entire volume served by such system, unless there
    is a permanent opening to an area the volume of which is
    equal to 25 percent of the entire volume served.
    Exception: Such openings when used for a heating or

    cooling air system in a dwelling unit shall be permitted

    to be reduced to not less than 50 percent of the required
    area, provided the balance of the required return air is
    taken from a room or hall having not less than three (3)

    doors leading to other rooms served by the furnace.
    (5) A closet, bathroom, toilet room, or kitchen.
    (6) From rooms or spaces containing a fuel-burning appliance
    therein.Where such room or space serves as source
    of return air.
    Exceptions:
    (1) This shall not apply to fireplaces, fireplace appliance,
    residential cooking appliance, direct vent
    appliance, enclosed furnaces, and domestic-type
    clothes dryers installed within the room or space.
    Kind of hard to follow the flow due to changes in fonts in the quote, but the way I read this and the way it makes the most sense is that the RED TYPE exceptions mean that they are allowed ONLY as related to item (6) but all the other prohibitions above still apply.
    i.e. - you CAN have a cooking appliance in a room that also has a return air vent but the prohibitions of item (4) above would still apply. Which means 75% of the return air of the system would have to come from another room.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  4. #4
    Join Date
    Sep 2008
    Location
    so so, California
    Posts
    1,769

    Default Re: Return air question

    Yea sorry about the fonts. I tried to fix this but for whatever reason couldn't. Anyhow, thanks for the info Jim, much appreciated.


    Quote Originally Posted by Jim Luttrall View Post
    Kind of hard to follow the flow due to changes in fonts in the quote, but the way I read this and the way it makes the most sense is that the RED TYPE exceptions mean that they are allowed ONLY as related to item (6) but all the other prohibitions above still apply.
    i.e. - you CAN have a cooking appliance in a room that also has a return air vent but the prohibitions of item (4) above would still apply. Which means 75% of the return air of the system would have to come from another room.


    The MAZZA INSPECTION GROUP
    www.mazzainspections.com
    Level III Thermo-picture-taker-er...er

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •