4BV18 – DuraVent 4″ × 18″ Type B Gas Vent Pipe

4BV18 DuraVent Type B Gas Vent Pipe

4BV18 by DuraVent is a 4-inch by 18-inch Type B gas vent pipe designed for compatible listed gas-fired appliances. Its double-wall construction combines an aluminum inner liner with a durable galvanized steel outer wall.

This pipe provides a factory-engineered section for properly designed Type B gas vent systems. It should only be used with compatible components and installed according to DuraVent instructions, the appliance manufacturer’s requirements and applicable local codes.

4BV18 Double-Wall Construction

The 4BV18 features an aluminum inner wall surrounded by a 28-gauge galvanized steel exterior. The inner liner creates the passage for combustion gases, while the outer wall provides additional protection and structural support.

The double-wall construction helps the vent warm quickly during appliance operation. Maintaining appropriate internal temperature can support natural draft and help reduce condensation within a properly sized and installed vent system.

The pipe has a nominal inside diameter of 4 inches, an exterior measurement of approximately 4.63 inches and a total height of 18 inches. It is manufactured in the United States and is identified as a UL-Listed component.

Type B Gas Vent Application

The 4BV18 is designed specifically as a Type B gas vent component. It may only be used with appliances, fuels and vent configurations approved by the equipment and vent manufacturers.

Do not use this pipe for wood-burning equipment, solid-fuel appliances or systems requiring another chimney classification. High-efficiency condensing furnaces and water heaters may require specialized plastic, polypropylene or stainless-steel venting instead of Type B pipe.

Always check the appliance rating plate and installation manual before selecting venting materials. The appliance documentation should identify the approved vent type, required diameter, clearance and termination method.

Four-Inch Diameter and 18-Inch Length

The 4BV18 has a nominal internal diameter of 4 inches and a pipe length of 18 inches. The additional length makes it useful for compatible installations requiring a longer straight Type B vent section.

Vent diameter must not be selected solely from the appliance outlet size. Appliance input capacity, vent height, horizontal distance, number of fittings and common-vent configuration can affect the required diameter.

A qualified HVAC professional should complete or verify the vent-sizing calculation. Incorrect sizing may affect draft, appliance operation and the safe removal of combustion gases.

UL-Listed Venting Component

The 4BV18 is identified as UL Listed. This listing applies when the pipe is installed within its intended DuraVent Type B system and used according to the manufacturer’s instructions.

Do not drill through, crush, alter or replace any part of the connection system. Unauthorized field modifications may damage the double-wall construction, affect required clearances or invalidate the product listing.

Compatible DuraVent Connections

The 4BV18 should be connected only to compatible 4-inch DuraVent Type B gas vent components. A complete installation may require additional pipe lengths, elbows, supports, firestops, roof flashing and an approved termination cap.

Do not mix components from different venting systems simply because they have the same nominal diameter. Manufacturers may use different locking methods, exterior dimensions and listing requirements.

Every connection should be completely engaged and secured according to DuraVent instructions. Inspect the completed vent route to confirm that all sections remain correctly joined and adequately supported.

Professional Installation Required

Installation of the 4BV18 should be performed by a qualified professional familiar with gas-fired equipment and Type B vent systems. The installer must verify sizing, clearances, supports, offsets, firestops, roof penetrations and termination requirements.

The complete vent system must maintain its specified clearance from combustible materials. Insulation, wood framing, electrical wiring and stored objects must not enter or obstruct the required clearance area.

The vent should rise according to the manufacturer’s instructions and should avoid unnecessary horizontal sections or directional changes. Proper supports help prevent movement, separation and excessive stress on the appliance connection.

Inspection and Maintenance

Have the venting system inspected periodically for corrosion, loose connections, physical damage and inadequate clearances. The exterior termination must remain free from leaves, nests, snow and other obstructions.

Possible warning signs include corrosion, condensation, soot, unusual odors or repeated appliance shutdowns. Stop using the affected equipment and contact a qualified professional if an unsafe condition is suspected.

Install and maintain carbon monoxide alarms according to local requirements and the alarm manufacturer’s instructions. Carbon monoxide alarms provide important protection but do not replace correct vent installation and professional inspection.

Product Specifications

• Manufacturer: DuraVent
• Model: 4BV18
• Product type: Type B gas vent pipe
• Nominal inside diameter: 4 inches
• Pipe length: 18 inches
• Approximate outside dimension: 4.63 inches
• Inner-wall material: Aluminum
• Outer-wall material: Galvanized steel
• Outer-wall thickness: 28 gauge
• Approval: UL Listed
• Country of origin: USA

Product and Installation Resources

Browse additional Type B vent pipe and installation supplies from Xpress Supply. Review the official DuraVent Type B Gas Vent information before installation.

Choose the 4BV18 when a properly designed venting system requires a UL-Listed 4-inch by 18-inch DuraVent Type B gas vent section. Confirm appliance compatibility, vent sizing and local requirements before ordering.