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Ducts on roof

Rick18071

Sawhorse
Joined
Nov 28, 2009
Messages
2,940
Location
Poconos/eastern PA
2015 IRC. I can't find the required insulation for ducts that are outside on the roof. Air handler on roof too. Section please..
 

mtlogcabin

Sawhorse
Joined
Oct 17, 2009
Messages
7,934
Location
Big Sky Country
Nothing in the IRC for ducts that are out side the building envelope and not in an attic. Commercial addresses it

2018 IECC
C403.11.1 Duct and plenum insulation and sealing (Mandatory).
Supply and return air ducts and plenums shall be insulated with not less than R-6 insulation where located in unconditioned spaces and where located outside the building with not less than R-8 insulation in Climate Zones 1 through 4 and not less than R-12 insulation in Climate Zones 5 through 8. Where located within a building envelope assembly, the duct or plenum shall be separated from the building exterior or unconditioned or exempt spaces by not less than R-8 insulation in Climate Zones 1 through 4 and not less than R-12 insulation in Climate Zones 5 through 8.
 

mp25

Registered User
Joined
Jun 2, 2016
Messages
98
Location
Illinois
1601.4.6 (2) Exterior duct systems shall be protected against the elements.
1103.3.1 Has insulation values - but only speaks to ducts in attics, ducts in other portion of the building and ducts completely within thermal envelope.

If the IRC doesn't cover a topic, reference IBC and its relevant section?
 
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