B Vent Pipes

How B vent pipe works

Also called type B gas vent, this pipe carries exhaust from the draft hood above the roof by natural draft. Type B vent has two metal walls with air between them and needs 1 inch of clearance to combustibles. The pipe and fittings lock together by hand with a twist, without screws or sealant.

Is this the right pipe?

Check your manual for water heaters, furnaces, boilers and B vent gas fireplaces. Wood stoves and wood fireplaces need class A chimney pipe. Pellet stoves need pellet stove pipe. It is not for sealed gas fireplaces, which use their own venting, such as DirectVent Pro pipe.

Which pieces do you need?

Plan your gas vent pipe installation from the appliance to the cap. The Model BV range includes round pipe and oval pipe for a standard 2 by 4 wall. A draft hood connector joins the appliance to the vent. Elbows turn the run. Tees and wyes join branches. The elbows and one pipe length are adjustable. Firestops and supports handle passages through the house. Roof flashing, a storm collar and a cap finish the top. Flexible connectors serve short appliance connections, while universal adapters join another maker’s pipe.

Why buy from My Cozy Outdoors?

We are an authorized dealer for DuraVent B vent, so the manufacturer warranty applies. For help choosing B vent pipe, call us and we will talk it through. Relining masonry? See our chimney liners. For wood stove venting, visit the Stove Pipe & Chimney Pipe hub.

FAQ

What is B vent pipe?

It is a double wall metal vent for natural gas or propane appliances that draw combustion air from the room. Water heaters, furnaces, boilers and B vent fireplaces use it to carry exhaust above the roof by natural draft. Never use it for wood.

What is the difference between B vent and direct vent?

B vent appliances use room air and need natural draft to a cap above the roof. A sealed fireplace draws outside air through its own pipe, which can exit through a wall or roof. The pipes are not interchangeable. Check your appliance manual.

Can B vent pipe go through a wall?

Yes, with a wall thimble, a tee and wall supports for the outside run. It cannot end at a wall. The cap must sit above the roof. Flexible connectors stay near the appliance and cannot pass through walls, floors or ceilings.

Can I cut B vent pipe to length?

No, do not cut B vent pipe. Its two walls and twist lock need factory ends. Plan the run before installing the appliance. Use fixed lengths and an adjustable length on the vertical run to fill the last gap.