Outside Ducts: Issues?
Outside Ducts: Issues?
(OP)
Besides not looking pretty, is there any code issues (or other concerns) which come to mind when running a duct along the outside of a building? From the ground to a 2nd floor? I know this is atypical, and code varies state to state, but I'm doing atypical HVAC applications...
Does this set off a red flag with anyone regarding any concerns, in general?
Thanks,
CuriouslyGeorge
Does this set off a red flag with anyone regarding any concerns, in general?
Thanks,
CuriouslyGeorge





RE: Outside Ducts: Issues?
However, when confronted with exterior ductwork the gage of the material is heavier than interior ductwork to protect from abuse. The insulation on the duct may be a rubber based material with a UV protective coating.
Also, I would try to ensure nobody can climb the duct and endanger themselves.
RE: Outside Ducts: Issues?
RE: Outside Ducts: Issues?
I like ductwork and mechanical equipment but everytime I drive past the building I cringe.... but no code issues that I know about.
RE: Outside Ducts: Issues?
After reading that book, you might have a totally different point of view about the "atypical" installations... Have fun.
RE: Outside Ducts: Issues?
If you're going to pick up a SMACNA book, get the important one: "HVAC Duct Construction Standards, Metal and Flexible". This one is the one most commonly cited in specifications regarding HVAC, and it contains details on supporting ducts from walls as well as a chapter on "Exterior Components."
RE: Outside Ducts: Issues?
Remember outdoor ductwork supports have to overcome wind loads, snow loads & temperature changes.
Architects may want it hidden from view or screened.
RE: Outside Ducts: Issues?
add a suitable drain in case water gets in.
Friar Tuck of Sherwood
RE: Outside Ducts: Issues?
I have lost confidence in metal jacketed insulation when we opened the insulation on roof mounted condenser water piping. The piping was so severely rusted the metal pelled off in circumferential layers. The entire piping run had to be replaced. The insulation vapor barrier was compromised & the jacket trapped moisture contributing to te rusting.
Properly applied elastomeric insulation with manufacturer's recommended adhesieve should not inflate and should be vaporproof.
RE: Outside Ducts: Issues?
chilled water piping in mech rooms gets armacell, outside gets pittsburg corning with alum jacket (make sure the PC gets sealed at the joints)
ductwork outside gets armacell with rubber roofing jacket or if its too costly, I spec armacell with factory applied weatherproof coating/mesh and exposed edges get a brush of coating (coating is by armacell)
osa ductwork in mech rooms gets armacell
just support and strap vertical ductwork outside
RE: Outside Ducts: Issues?
I have experienced the same on exterior metal-jacketed condenser water pipe, but only with fiberglass insulation. The fiberglass absorbs any water that makes its way through the jacketing, and the piping stays wet for a long time. There are enough closed-cell options for pipe covering that I don't allow fiberglass at all anymore. Armacell and styrofoam are good for low temperature; polyisocyanurate (Dow Trymer) is good for up to 300F.
A good alternative to metal jacketing on exterior piping is UV-resistant PVC, with all solvent welded joints.
---KenRad