Jump to content

Plumbing in a return plenum


elgato

Recommended Posts

Is it "OK" to have plumbing ( or wiring, for that matter ) in HVAC ducts? Couldn't condensation occur as cold water runs through the plumbing while warm air runs through the duct? Of course winter air is very dry, but there could be situations in the transition months.

Click to Enlarge
tn_20105610618_P5050043.jpg

31.7 KB

Link to comment
Share on other sites

Is it "OK" to have plumbing ( or wiring, for that matter ) in HVAC ducts? Couldn't condensation occur as cold water runs through the plumbing while warm air runs through the duct? Of course winter air is very dry, but there could be situations in the transition months.

Click to Enlarge
tn_20105610618_P5050043.jpg

31.7 KB

Nope! Nothing but air should be in that return.

Link to comment
Share on other sites

Wires can pass through:

From the 2006 IRC.

- - E3804.7 Air handling—stud cavity and joist spaces. Where wiring methods having a nonmetallic covering pass through stud cavities and joist spaces used for air handling, such wiring shall pass through such spaces perpendicular to the long dimension of the spaces.

I tend to remember that distribution pipes can pass through as well. Scott, do you have a code cite for the prohibition of pipes through the return?

I do have issue with a drain line passing through, and if it is not covered by the IRC, it should be. I'd have to look it up, and am too lazy right now.

Link to comment
Share on other sites

When it comes to electrical wires in return ducts created by attaching pan metal or ductboard to floor joists, the position of my local AHJ is that the wire can be installed perpendicular to the floor joists, but not parallel with the joists.

Do you NEC guys know whether this is actually addressed by the code, or is it some sort of skewed interpretation?

Link to comment
Share on other sites

Wires can pass through:

From the 2006 IRC.

- - E3804.7 Air handling—stud cavity and joist spaces. Where wiring methods having a nonmetallic covering pass through stud cavities and joist spaces used for air handling, such wiring shall pass through such spaces perpendicular to the long dimension of the spaces.

I tend to remember that distribution pipes can pass through as well. Scott, do you have a code cite for the prohibition of pipes through the return?

I do have issue with a drain line passing through, and if it is not covered by the IRC, it should be. I'd have to look it up, and am too lazy right now.

We were typing at the same time . . . though in my defense, I was also eating dinner and watching the news.

Link to comment
Share on other sites

Wires can pass through:

From the 2006 IRC.

- - E3804.7 Air handling—stud cavity and joist spaces. Where wiring methods having a nonmetallic covering pass through stud cavities and joist spaces used for air handling, such wiring shall pass through such spaces perpendicular to the long dimension of the spaces.

I tend to remember that distribution pipes can pass through as well. Scott, do you have a code cite for the prohibition of pipes through the return?

I do have issue with a drain line passing through, and if it is not covered by the IRC, it should be. I'd have to look it up, and am too lazy right now.

No, I don't have a cite.

But, I bet it would fall under the parts about the duct fire blocking, ASTM C 411(has to do with flame spread and how hot things can get before they start to smoke), ASTM E 84 (flame spread) and a few other items...

Link to comment
Share on other sites

Copper has a flame spread rating? I bet it exceeds foil faced rigid ducting. Here's the down side to copper in the plenum.... it gets hot enough in the plenum to burn the copper releasing water and extinguishing the fire.

Wait, that's not a down side.

Link to comment
Share on other sites

  • 3 months later...
  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...