Cleanroom Air Distribution Systems

HVAC Duct Wrap Insulation

A flexible glass-fiber blanket laminated to a reinforced foil vapor retarder for external thermal and acoustic insulation of metal air ducts.

Flexible Glass-Fiber Blanket
Reinforced Foil Vapor Retarder
Thermal and Acoustic Control
Fits Rectangular and Round Ducts

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Product Introduction

HVAC duct wrap insulation is installed around the exterior of sheet-metal supply and return ducts to reduce heat gain, heat loss and surface condensation. The resilient glass-fiber blanket conforms to rectangular corners and round profiles, while the factory-applied foil-scrim-kraft or reinforced foil jacket forms the external vapor retarder. Circumferential and longitudinal seams are overlapped and sealed continuously. Installed thickness accounts for compression at duct corners so that the specified thermal resistance is maintained over the complete surface.

Key Features

Flexible glass fibers conform around fittings and transitions without rigid board joints at every change in shape.

A reinforced foil facing combines a clean external finish with a low-permeance vapor-control layer.

Multiple densities and thicknesses allow insulation value to be selected without excessive bulk.

The fibrous blanket also absorbs casing-radiated fan and airflow noise from metal duct surfaces.

Customer Product Concerns

Duct wrap must remain continuous at corners, hangers and fittings because small gaps in the vapor retarder can produce large areas of condensation.

Cold duct surfaces sweat above the cleanroom ceiling.A continuous insulation layer and sealed low-permeance foil jacket keep the outer surface above the local dew point.

Corner compression reduces the installed thermal resistance.The selected blanket thickness allows for expected compression and uses proper corner wrapping technique.

Staples and hanger penetrations puncture the vapor barrier.Compatible pressure-sensitive foil tape closes seams and all penetrations after fastening.

Unfaced insulation releases fibers into the service void.The factory-laminated facing encloses the exposed blanket surface and is sealed at cut edges.

Typical Applications

Cold supply-air duct insulationReturn-air thermal controlCleanroom ceiling ductworkAir-handling-unit plenumsRound and rectangular HVAC fittings

Technical Parameters

Typical ranges for foil-faced flexible glass-fiber duct wrap are listed below.

Core Material	Resilient glass-fiber blanket bonded with thermosetting resin
Panel Thickness	25–50 mm nominal blanket thickness
Effective Width	1200 mm standard roll width
Maximum Length	15000–30000 mm standard roll length, depending on thickness
Steel Facing Thickness	0.05–0.15 mm reinforced foil laminate facing
Core Density	20–48 kg/m³
Thermal Conductivity	0.034–0.043 W/(m·K) at approximately 24°C mean temperature
Surface Finish	Foil-scrim-kraft or reinforced aluminum foil vapor-retarder facing
Joint Type	Overlapped wrap seams sealed continuously with pressure-sensitive foil tape
Customization	Available based on the intended application and operating environment.

Available Options

25, 38 or 50 mm thickness20–48 kg/m³ nominal densityFSK or all-service foil facingPre-cut widths for standard duct sizes

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