4.1601.7 Insulating Metal Ducts—Mid and High Rise

Topic: 
Ducts
Subtopic: 
Insulating Ducts
Desired Outcome: 
Lowered thermal conductance of duct system and minimized condensation on the duct system
TitleSpecification(s)Objective(s)
4.1601.7a
Selection of duct insulation material

Duct insulation will be a minimum of R-8, in accordance with local code, or buried under attic insulation, whichever is greater, and have an attached vapor barrier Vapor barrier A material that retards the passage of water vapor and contains a perm rating of less than 1

Ducts will not be buried in hot humid and warm coastal regions

Decrease heat loss and condensation problems

4.1601.7b
Duct sealing

Before insulation is applied, all accessible ducts will be sealed with a UL UL Underwriters Laboratories -approved mastic in conformance with the applicable code adopted by the jurisdiction

Minimize duct leakage

4.1601.7c
Attachment of duct insulation

Duct insulation will be secured to the duct system using an appropriate material per applicable standards that will securely hold the insulation to the ductwork, without compressing the insulation in the process

Ensure a secure connection between the duct system and the duct insulation

4.1601.7d
Sealing of the duct insulation

Using a tape or mastic approved by the manufacturer, all seams and connections of the duct insulation will be sealed

No gaps will exist between pieces of duct insulation

Prevent gaps in the vapor barrier Vapor barrier A material that retards the passage of water vapor and contains a perm rating of less than 1 of the insulation