View Full Version : Can copper and pvc piping be in return?
04-26-2005, 02:35 PM
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?
04-26-2005, 02:51 PM
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.
tinknocker service tech
04-26-2005, 03:43 PM
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.
04-26-2005, 03:54 PM
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.
04-26-2005, 08:32 PM
if this is a diy and not a permit job you can do anything you want to do.
04-26-2005, 08:59 PM
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.
04-26-2005, 09:41 PM
We "Swallow" these types of problems with an experienced tinner, and extra charge.
04-26-2005, 11:30 PM
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.
04-27-2005, 12:16 AM
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.
04-27-2005, 01:07 PM
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.
btj steamfitter / ref
04-27-2005, 08:10 PM
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)
04-27-2005, 08:41 PM
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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