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  1. #1
    Join Date
    May 2004
    Posts
    80
    I need to install a return air drop in a 14" x 5 1/2" wall cavity. The ideal location has a 1/2" cold water line and a 1 1/2" pvc drain pipe running through it. I've got plenty of square inches for my air-even with the pipes. My question is, would sharing return air with copper and pvc piping be a code violation? What if it were just the copper water line?

  2. #2
    Join Date
    Nov 2001
    Posts
    1,874
    Around here we can run something through it side to side but we can't run it though length wise.

    If the pvc is a vent you may be ok,
    if it's a drain or sewage, NO.

    You have have to use metal duct in the chase to keep from having the pipes shut you down.
    If you try to fail, and succeed.
    Which have you done ?



  3. #3
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,510
    from what i have learned any plastic pipe can not be in a return be cause if burned in a fire can cause toxic fumes
    copper is not a problem
    some earas are differant
    call the inspector and he can tell what the code is on this rather than guess or listen to us because he has final sayso.

  4. #4
    Join Date
    May 2004
    Posts
    80
    The pvc is a sink drain. It only occupies 2" in one corner, then elbows into the next lane over. I can build around it so it's not in the airway.

  5. #5
    Join Date
    Aug 2001
    Posts
    1,936
    if this is a diy and not a permit job you can do anything you want to do.

  6. #6
    Join Date
    May 2004
    Posts
    80
    I'm an HVAC contractor, at least part of the time. This is in my own home. Still, I like to adhere to general building codes-hence the inquiry.

  7. #7
    Join Date
    Jun 2000
    Location
    WYO
    Posts
    2,019
    We "Swallow" these types of problems with an experienced tinner, and extra charge.
    never say never

  8. #8
    Join Date
    May 2001
    Location
    Kansas City
    Posts
    2,729
    Anything in return space has to be plenum rated, in other words it can't put out toxic fumes if burned. PVC or ABS or romex wire is toxic if burned.
    You can put return grill above or below the pipes and use 2x4 to block off. Or use 2" electrical metal conduit as a sleve for the plastic pipe where it goes thru return stud spsce.
    Is your house going to catch fire and burn that wall sucking toxic fumes into the ductwork and blow it into the bedrooms where you and family are sleeping? Doubt it, but what if.

  9. #9
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,403
    Could you cover the pipe (or box it out) with panning? I know panning won't last long in a fire, but hey, they seem to think it's "ok" to use anyway.

  10. #10
    Join Date
    May 2004
    Posts
    80
    I'm going to pan off the plastic with a small wood frame covered with metal panning. Probably overkill, but that should do it. The copper water pipe I'll leave alone.
    Service, heat load calcs, and general duct design I'm fine with. I'm no tinner, though I have my moments. Input from others is almost always good. Thanks.

  11. #11
    just make a pair of pants in the duct ( I always call it a pair of jeans on the job to piss the tinbangers off)

  12. #12
    Join Date
    Mar 2005
    Posts
    65

    Depends on the inspector

    I have found that it really depends on the inspector and what side of the bed he/she woke up on that morn.... I have had inspectors tell me as long as I masticked it up and sealed the penetrating point that it is "ok", on the other hand I have had a few (but not many) fail it and tell me to re-route it around the return. To each his own i guess.

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