Duct Insulation - Spray Polyurethane Foam (SPF)

Detail ID 5.0107.2
Topic
Forced Air
Subtopic
Duct Insulation
Desired Outcome

Safe and durable SPF duct insulation

SF Single Family Site-Built Housing
MH Manufactured Housing
MF Multifamily Housing

Specifications

  • SF
  • MH
  • MF
Specification Objective

Select SPF that has a flame spread and smoke development index of 25/450 or less when tested in accordance with ASTM E84 or UL 723 at its installed thickness

Select fire safe insulation

  • SF
  • MH
  • MF
Specification Objective

Remove contaminants from all SPF application surfaces that will prevent full adhesion or cause degradation

Verify all SPF application surfaces are in accordance with manufacturer specifications for moisture content and temperature

Cover all holes, cracks, gaps, etc. where SPF may enter the interior of the duct with a temporary backing material (e.g., foil tape)

Properly bonded SPF only on the exterior of ducts

  • SF
  • MH
  • MF
Specification Objective

Apply SPF to the prescribed R-value in a continuous layer over entire exterior duct surface using a pass thickness maximum in accordance with manufacturer specifications

No SPF may be installed on ducts inside the thermal boundary

Airtight and properly insulated ducts that do not threaten indoor air quality

  • SF
  • MH
  • MF
Specification Objective

Separate all foam products from living space with a thermal barrier material (e.g., 1/2" gypsum wallboard) as specified by applicable building code

If space is used only for the service of utilities, foam will be separated from the space using a suitable ignition barrier covering or coating according to manufacturer's specifications

If space is used for storage or occupancy, spray foam will be separated from the space using a thermal barrier material (e.g., 1/2" gypsum wallboard) as specified by applicable building code and manufacturer specifications

If code requirements are unclear, consult local code officials for clarification

Minimize ignition and combustion potential

  • SF
  • MH
  • MF
Specification Objective

Post a dated receipt signed by the installer that minimally includes: Installed insulation type, coverage area, installed thickness, and installed R-value

Comply with 16 CFR 460.17 and document contract compliance

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General Duct Insulation
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Duct Insulation