Quietflex 40seriesbag Flex Duct R4.2 14in 25ft

Product Description

The QUIETFLEX 40seriesbag is a round, insulated flexible air duct designed for residential and commercial HVAC distribution systems. Constructed with a galvanized metal inner core and a polyester vapor barrier jacket featuring rip-stop scrim reinforcement, this duct delivers an R4.2 thermal rating. The silver metallic outer jacket resists moisture and physical damage during and after installation. Johns Manville formaldehyde-free fiberglass insulation fills the annular space between the inner core and outer jacket. The duct ships in weather-resistant packaging and is sized at 14 inches in diameter across a 25-foot length, supporting airflow up to 6,000 CFM. Licensed HVAC technicians and mechanical contractors are the primary installers of this product.

This flexible duct is suited for supply and return air applications in forced-air HVAC systems where a 14-inch round duct connection is required. The oversized inner core is designed to fit over standard collars and register boxes without modification. It is appropriate for use in residential attics, crawlspaces, and mechanical rooms, as well as light commercial applications. The product meets HUD/FHA standards 515.2.1 Paragraph B, NFPA standards 90A and 90B, BOCA standards, City of Chicago codes, and most federal, state, and local mechanical codes.

Key Features

• R4.2 insulation value using Johns Manville formaldehyde-free fiberglass insulation
• Rip-stop polyester vapor barrier outer jacket resists tearing and moisture intrusion
• Galvanized metal inner core provides structural rigidity and airflow integrity
• Oversized core diameter fits standard collars and register boxes
• Rated for airflow up to 6,000 CFM
• Weather-resistant packaging protects the product during storage and transport
• Greenguard Certified insulated construction

Compatibility

Designed for use in forced-air HVAC duct systems requiring a 14-inch round flexible duct connection. Meets UL 181 Class 1, NFPA 90A and 90B, HUD/FHA 515.2.1 Paragraph B, BOCA, City of Chicago, and most federal, state, and local codes and standards. Tested per ASTM C518.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified mechanical contractor in accordance with NFPA 90A, NFPA 90B, and applicable local mechanical codes. Shut down the air handling unit and disconnect power before connecting or repositioning flex duct runs. Avoid sharp bends, compression, or excessive sag, as these conditions reduce airflow efficiency and can void listings. Secure both ends with approved clamps or mastic sealant per UL 181 listing requirements.

Technical Specifications

• Diameter: 14 inches
• Length: 25 feet
• R-Value: R4.2
• Maximum Airflow: 6,000 CFM
• Duct Shape: Round
• Insulated: Yes
• Jacket Material: Polyester
• Core Material: Steel (Galvanized)
• Jacket Color: Silver
• Listing: UL 181 Class 1
• Test Standard: ASTM C518
• UPC: 878640001448

Standard Information

• Brand: QUIETFLEX
• Manufacturer Part Number: 40seriesbag