| 4.1601.3a
Ducts in unconditioned spaces (e.g., crawl space, attic, unconditioned basements) | Ducts will have continuous insulation and
vapor barrier
Vapor barrier
A material that retards the passage of water vapor and contains a perm rating of less than 1
Insulation will be sufficient to prevent dew point on surface of ducts | Minimize condensation |
| 4.1601.3b
Ducts within floor assemblies | Inspection and/or testing will be conducted to determine whether ducts are within thermal, pressure, and vapor boundary If ducts are within thermal, pressure, and vapor boundary, no action will be required If ducts are not within thermal, pressure, and vapor boundary, continuous
air barrier
Air barrier
The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary
, insulation, and
vapor retarder
Vapor retarder
A material that slows the passage of water vapor and contains a perm rating above 1
will be installed either on the ducts or at the belly liner | Minimize condensation |
