Metal-fab 16M18A B-vent Big Vent Adjustable 18 Inches

Product Description

The METAL-FAB 16M18A is an adjustable-length B-vent pipe section designed for Type B gas venting systems. It provides flexible length adjustment to accommodate varying installation depths and rough-in dimensions without cutting fixed-length pipe. This fitting is part of the Big Vent product line, which is engineered for larger-diameter venting applications. HVAC technicians and gas appliance installers use adjustable sections like this one to achieve precise runs between fittings, appliances, and roof penetrations while maintaining proper draft and venting efficiency.

This adjustable B-vent section is suited for residential and light commercial gas appliance venting, including furnaces, boilers, and water heaters that require Type B double-wall vent pipe. The adjustable design is especially useful when field conditions do not match a fixed pipe length, reducing the need for additional couplings or custom cuts. It is intended for use in new construction and retrofit installations where certified Type B venting is required by the appliance manufacturer or local code.

Key Features

• Adjustable length design accommodates variable run distances without cutting
• Type B double-wall B-vent construction for approved gas appliance venting
• Part of the Big Vent product line for larger-diameter venting applications
• Reduces the need for extra couplings or adapters in tight installations
• Compatible with standard Type B vent system components

Compatibility

Designed as an OEM-style component for Type B gas vent systems requiring adjustable pipe sections in larger-diameter configurations.

Installation Notes

Type B gas vent installations must be performed by a licensed HVAC technician or qualified gas appliance installer in accordance with NFPA 54 and the appliance manufacturer's venting instructions. Shut off and lock out the gas supply and disconnect power to the appliance before servicing or modifying any vent run. Ensure all joints are fully engaged and secured per the vent system manufacturer's instructions, and verify proper clearances to combustibles throughout the entire vented run.