Thanks to its excellent products and quality services, UNT Duct is one of the leading lightweight pu pre-insulated duct manufacturers and suppliers in China. Welcome to buy the high quality and customized products from our factory. We will offer you the best service and fast delivery.

Lightweight PU Pre-insulated Duct

Lightweight PU (Polyurethane) Pre-insulated Duct is a modern alternative to traditional metal ductwork for heating, ventilation, and air conditioning (HVAC) systems . It is a composite panel that combines thermal insulation and air-conveying functions in one product.

What Is It Made Of?

The duct is built as a rigid "sandwich" panel:

Core Material: A rigid polyurethane (PU) foam, which provides excellent thermal insulation . Some variations use PIR (polyisocyanurate) for enhanced fire resistance.

Facing Material: Both sides of the foam core are typically laminated with an aluminum foil layer. For external or more demanding applications, the facing can be a thicker aluminum sheet or pre-painted galvanized steel. For cleanroom environments, a smooth aluminum foil finish is often used.

Polyurethane (PU) Foam Pre-Insulated HVAC Ductwork Panel

Key Advantages of Lightweight PU Pre-insulated Duct Over Traditional Metal Ducts

Lightweight PU ducts offer several practical and performance benefits:

Significantly Lighter:

Weighing about 1.3 to 1.4 kg/m², they are much lighter than galvanized steel ducts (around 8.3 kg/m²), which reduces building structural load and simplifies handling.

Faster and Simpler Installation:

They require a single-step installation process, eliminating the need to add separate insulation and vapor barriers later.

Excellent Thermal Insulation:

The polyurethane foam core has a very low thermal conductivity of approximately 0.02 W/m·K, which minimizes energy loss and prevents condensation.

Space-Saving:

The system is compact, reducing the ceiling space needed for ductwork.

Longer Service Life:

PU ducts are reported to have a service life of more than 20 years, compared to 6-7 years for traditional galvanized iron ducts.

The Fabrication Process of Lightweight PU Pre-insulated Duct

Step 1 – Tracing
Outline the required duct shapes directly onto the panel surface according to the design drawings.

Step 2 – Cutting
Using manual cutting tools, trim the panel edges and cut 90° "V"-shaped grooves into the panel where bends are required.

Step 3 – Gluing
Apply a uniform layer of adhesive to the prepared cutting surfaces of the panels.

Step 4 – Folding
Once the adhesive has fully cured, fold the grooved side panels toward each other to form the straight duct section.

Step 5 – Taping
Apply sealing tape exclusively to the external longitudinal seams where the panel edges meet, to ensure air-tightness.

Step 6 – Flanging
After applying adhesive and positioning the steel angle brackets, install the PVC or aluminum invisible flanges at the duct ends.

Step 7 – Reinforcement
If required, reinforce the duct assembly using aluminum reinforcement bars and G.I. (galvanized iron) shaped disks for added structural stability.

Step 8 – Sealing
After the duct is fully assembled, hermetically seal all internal joints and corners with silicone sealant to guarantee complete air-tightness.