This guide will help you understand the different types of piping systems that are available and which one will work for your system.
Chimney Pipe is the term used for wood-burning appliances and includes class A chimney pipe and stove pipe. Venting pipe is used for gas appliances and includes direct vent pipe, type B gas vent pipe, and pellet vent pipe.
Before any installation, it is imperative to read the instruction manual to determine the venting requirements for your appliance. You should also check with your local building codes to ensure you are in compliance.
Class A Chimney Pipe
Class A chimney pipe is used for wood-burning fireplaces and stoves. It is also used when transitioning stove pipe through a wall or ceiling. It is often referred to as double-wall, triple-wall, all-fuel or insulated chimney pipe.
It is composed of either double-wall or triple-wall pipe, although most triple-wall pipe is becoming less prevalent. The inner pipe encases heat emitted from fireplaces and carries combustion particles outside. The space between the inner and outer walls function as an air jacket by insulating the chimney pipe and keeping the surface of the outer wall from becoming too hot.
It is important never to mix and match different brands within one chimney system. Each brand is specifically engineered and must be used together from beginning to end. If the brand you have is discontinued or obsolete, unfortunately, you must start from scratch.
You will typically have a choice between galvanized steel or stainless steel. Since galvanized steel is cheaper, it makes sense to use it when it is not exposed. If the pipe will be exposed, it’s better to use stainless steel because it looks better, and galvanized steel will eventually rust and corrode if it’s exposed to the elements. If you do use galvanized steel outside, it is recommended to paint the steel with a high-temperature, rust-resistant paint.
Direct Vent Pipe
Direct vent pipe is used specifically for direct vent gas or propane stoves and fireplaces. It is one of the most popular types of venting because of its efficiency and ease of installation.
Direct vent uses outside air for combustion and vents all exhaust back outside using either co-axial or co-linear piping.
Co-axial pipe is a pipe-within-a-pipe system. It utilizes a smaller inner pipe that is fixed inside a larger outer pipe, separated by spacers. The inner pipe (exhaust pipe) removes combustion by-products and vents the exhaust out of the appliance and home. The outer pipe (intake pipe) brings fresh air from outside for combustion.
Co-linear pipe uses two separate pipes, an intake pipe and an exhaust pipe. This type is typically only used if you are utilizing an old chimney and if the fireplace manufacturer has tested it.
Stove Pipe
Stove pipe is used for venting wood-burning stoves and should only be used in the room where the stove is installed. Once the pipe reaches a wall or ceiling, it must be converted to class A pipe because stove pipe is not designed with the necessary clearances from combustible materials to go through walls or ceilings.
If you are converting through the ceiling, a ceiling support box or round ceiling support piece is required. If you are converting through-the-wall, a thimble is required. Stove pipe is also referred to as black pipe and single-wall pipe.
Type B Gas Vent Pipe
Type B gas vent is used mostly in older homes and isn’t as prevalent in hearth venting today. It is a double-wall metal pipe used for venting appliances with draft hoods.
Type B is less efficient than both direct vent and vent-free units because it must terminate through the roof and could potentially blow cool air into the house if downdraft occurs. Type B is also referred to as b-vent or natural vent.
Pellet Vent Pipe
Pellet vent is used for pellet or corn-burning stoves. These pipes have a small diameter (3-4 inches) and typically only require a 1-inch clearance to combustibles.
Pellet vents can be used from start to finish, including through walls and ceilings, and can be terminated horizontally or vertically.
Have More Questions about Chimney and Venting Pipes?
We've detailed the common types of vent piping and their uses above, but if you're still in need of assistance with choosing the right solution for your home, we're here to help. You can contact us via email or give us a call at 877-374-2070 Monday through Friday, 9 a.m. to 5 p.m. Central Time. Our home hearth experts are ready to offer their assistance.