Atco 070-R4.2_20X25FT Flexible Air Duct R4.2 20x25 Ft

Product Description

The ATCO RUBBER PRODUCTS 070-R4.2_20X25FT is a Class 1 insulated flexible air duct designed for residential and commercial HVAC distribution systems. Measuring 20 inches in diameter and 25 feet in length, it features a 2-ply polyester inner core and a thick blanket of fiberglass insulation rated at R4.2. The gray polyester outer jacket resists tearing and puncture while keeping the fiberglass encapsulated, preventing erosion into the airstream. Rated for air velocities up to 5000 FPM and a positive static pressure of 4 inches WG per UL 181, this duct handles demanding airflow conditions. HVAC technicians and sheet metal contractors install this duct in forced-air distribution applications where thermal efficiency and code compliance are required.

This flexible duct is suited for trunk-to-register runs in residential forced-air systems and light commercial HVAC installations. The plain-end configuration allows field cutting to length without unraveling, thanks to the encapsulated wire helix design. The smooth inner core reduces friction loss and lowers operating costs compared to corrugated alternatives. It is appropriate for supply-air applications within conditioned spaces where R4.2 insulation meets local energy code minimums. The duct carries ratings under UL 181, NFPA 90A and 90B, IMC, IRC, UMC, HUD, and ASTM C-158, supporting permit-ready installations across most jurisdictions.

Key Features

• R4.2 thick blanket fiberglass insulation for energy-efficient thermal performance
• 2-ply polyester inner core rated to 5000 FPM air velocity
• Encapsulated wire helix prevents unraveling when cut, speeding field installation
• Smooth inner core minimizes friction loss and reduces system operating cost
• Gray polyester outer jacket resists tearing, puncture, and general jobsite abuse
• Rated 4 inches WG positive and 3/4 inch WG negative pressure per UL 181

Compatibility

Designed as an OEM-style Class 1 flexible duct replacement or new-install component for residential and light commercial forced-air HVAC distribution systems requiring R4.2 insulation and UL 181 listing.

Installation Notes

Installation should be performed by a licensed HVAC technician or sheet metal contractor in accordance with NFPA 90A, NFPA 90B, and the applicable mechanical code (IMC, UMC, or IRC). Power down the air handling unit and close the system dampers before connecting or replacing duct sections. Support the duct at intervals per manufacturer and code requirements to prevent sagging, which increases static pressure loss. Do not compress or over-bend the duct, as sharp bends significantly reduce effective airflow.

Technical Specifications

• Diameter: 20 inches
• Length: 25 feet
• Air Velocity Rating: 5000 FPM
• Rated Positive Pressure: 4 inches WG per UL 181
• Rated Negative Pressure: 3/4 inch WG per UL 181
• Insulation Type: Thick Blanket Fiberglass
• Insulation Value: R4.2
• Core Material: 2-Ply Polyester
• Jacket Material: Gray Polyester
• Duct Type: Class 1, Insulated, Flexible, Plain End
• Temperature Rating: -20 to 180 degrees F continuous, -20 to 250 degrees F intermittent
• Flame Spread: Maximum 25
• Smoke Developed: Maximum 50
• Applicable Standards: UL 181, NFPA 90A and 90B, IMC, IRC, UMC, HUD, ASTM C-158

Standard Information

• Brand: ATCO RUBBER PRODUCTS
• Manufacturer Part Number: 070-R4.2_20X25FT