Metal-fab 4MO6 Type B Oval Gas Vent Pipe 4x6 Inch

Product Description

The METAL-FAB 4MO6 is a Type B double-wall oval gas vent pipe designed for use in residential and light commercial venting systems. This 4-inch diameter by 6-inch length section features an aluminum alloy inner wall at 0.012 inches thick and a G90 galvanized steel outer wall at 0.018 inches thick. The oval profile suits installations where space is limited. A Twist-Lock connection with a locking tab secures joints without sheet metal screws, reducing installation time and the risk of connection failure. Tested and listed to UL 441, this fitting meets the standard for approved gas appliance venting.

The 4MO6 is used in Type B gas venting runs for natural gas and propane appliances including furnaces, water heaters, and boilers. The oval form factor is selected for venting chases or wall cavities where a round pipe would not fit. It is typically installed by licensed HVAC technicians or plumbers working on gas appliance venting systems in residential construction and retrofit applications. The double-wall design maintains flue gas temperature to support proper draft and reduce condensation within the vent run.

Key Features

• Tested and listed to UL 441 for Type B gas appliance venting
• Twist-Lock connection with locking tab — no sheet metal screws required
• Double-wall construction: aluminum alloy inner wall, G90 galvanized steel outer wall
• Inner wall thickness 0.012 inches, outer wall thickness 0.018 inches
• Oval profile for space-constrained venting chases and wall cavities
• Hemmed flues and casings improve durability and connection reliability

Compatibility

Designed as an OEM-style replacement or system component for Type B gas vent installations using 4-inch oval vent pipe sections listed to UL 441.

Installation Notes

Installation must be performed by a licensed HVAC technician or plumber in accordance with the appliance manufacturer instructions, NFPA 54 National Fuel Gas Code, and local mechanical codes. Shut off the gas supply and allow the appliance to cool completely before servicing any vent section. Align the Twist-Lock connection fully and confirm the locking tab is seated before restoring operation. Maintain required clearances to combustibles as specified by the vent listing and local code.

Technical Specifications

• Type: Type B Double Wall Oval Gas Vent
• Diameter: 4 inches
• Length: 6 inches
• Inner Wall Material: Aluminum Alloy
• Outer Wall Material: G90 Galvanized Steel
• Inner Wall Thickness: 0.012 inches
• Outer Wall Thickness: 0.018 inches
• Listing: UL 441

Standard Information

• Brand: METAL-FAB
• Manufacturer Part Number: 4MO6