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Class A Chimney Pipe

Chimney pipe (Class-A chimney pipe) is often used when high-temperature exhaust gases need to be vented from burning common solid fuels such as wood, coal, oil, and other solid fuels. Not every situation requires Class-A chimney pipe, but in high-temperature situations you can't do without it. Shop our large selection and choose the size and style right for your chimney and fireplace, then get your installation done right the first time using Class-A chimney pipe from our store.
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By Lewis from Hopatcong, NJ on September 11, 2013
I need to vent a oil fired furnace with an 8" pipe. Total chimney height is 30 ft. The chimney will be contained in a wood chase 16 x 16. What would be my best choice for the chimney?
By Tyler M. - NFI Certified Specialist on September 11, 2013

We recommend using DuraVent's DuraTech class A chimney pipe. This is a double-wall, solid pack insulated chimney pipe that has an 8" inner diameter and a 10" outer diameter.

By Carolyn from Longmont, CO on January 22, 2014
We purchased a Solana by Lennox EPA woodburning fireplace. It is too big. We are interested in one of your fireplaces. The pipe and connections we purchased are 8" Class A ASHT chimney.

Can we use this pipe on your fireplace which requires 8" pipe?
By Tyler M. - NFI Certified Specialist on January 22, 2014

The vast majority of our woodburning fireplaces with an 8" only accept the manufacturers' own chimney pipe. However, we offer one woodburning fireplace that can indeed utilize your Secure-Temp ASHT+ 8" diameter chimney; it is the Napoleon High Country NZ6000 Wood Burning Fireplace. That model measures approximately 51 1/2" tall by 48 5/8" wide and 31 3/4" deep.

By Joshua from WI on August 13, 2013
I have a 24./12 pitch roof on an A-frame cabin. Obviously I have a fairly large hole in the ceiling that I need to trim out in the interior side of the cabin. Will the following product fit my roof pitch?
By Collin C. - NFI Master Hearth Professional on August 14, 2013

Unfortunately, this manufacturer only produces their trim kit to fit up to a 12/12 roof pitch. I was not able to locate a manufacturer that produces a finish plate that will accommodate a 24/12 pitch. It is likely that you will need to have a trim plate custom made by a metal shop. I apologize that we do not carry a trim that will work.

By Paul from Texas on January 13, 2014
I have bought an FMI 42" bungalow wood burning FP with 8 " opening. What pipe and other materials do I need ? Does it have to make an angle before going straight up ( if so how high before the angle ) or can I build it going straight up without any draw problems ? Does the flue pipe hole need to be at least 3/4" wider than the pipe? What do I use for sealant of a rain cap? This is new construction with no existing chimney.

By Tyler M. - NFI Certified Specialist on January 13, 2014

FMI 8DM chimney pipe is required for your Bungalow fireplace. This pipe has an 8" inside diameter and a 12 3/8" outside diameter. It is ideal to run your chimney as straight as possible--straight up being the best option in all applications. The pipe requires a 2" clearance to all combustibles, so provisions must be made for approximately a minimum of 14 1/4" diameter space for the pipe to run through. We carry firestop flanges that would be used for combustible ceiling and floor penetrations. For a full quote, please fill out our Chimney Pipe Design & Quote Form.

By Ronald from White Cloud , MI on April 1, 2013
My masonry has an 8" tile flue, however we are using wood stove insert in the fireplace for heating and it works well. My question is, when we installed the insert we installed a 6" flex liner inside the chimney, which has been a problem. Do we need to remove it for inspection and are replacements still available?
By Tyler M. - NFI Certified Specialist on April 2, 2013

Given how long your liner has been installed, it certainly should be cleaned and inspected. Depending on its quality, it may need to be replaced. We recommend contacting a local chimney sweep for cleaning and inspection.

By Stephanie from Suffolk, VA on March 17, 2013
I would like to build an outdoor fireplace without using a firebox, but use a class a flue. What would I need to do this?
By Collin C. - NFI Master Hearth Professional on March 18, 2013

If you are site building a fireplace, but would like to use Class A pipe to vent it, you will need to use an anchor plate to transition from the firebox to the chimney. An example is the DuraTech All-Fuel Chimney Pipe Masonry and Zero-Clearance Fireplace Anchor Plate - For Chimney Pipes with an 8-Inch Inner Diameter - 9641. The plate will bolt over the opening that would be cut into the box to allow venting. Actual diameter of the chimney will depend on the size of the opening for your box. The ideal ratio is 10 to 1, which 1 square inch of flue to 10 square inches of fireplace opening. A chimney that is too small or large can cause drafting issues, including smoke spillage and overfiring.

By Anthony from San Antonio, TX on October 15, 2014
I'm building a house and I plan on putting a chimney down stairs and one right above it in the bedroom on the 2nd floor and want to use the same wooden chase. Can I connect them on the same exhaust pipe?
By eFireplaceStore on October 15, 2014

Chimney piping can be run side by side in an adjacent chase, however the two chimney pipes must remain independent of one another and terminate independently at the top of the chase.

By Steele from Cleveland on November 26, 2012
How can I tell if my existing chimney is Class A pipe?
By Collin C. - NFI Master Hearth Professional on November 27, 2012

It is standard for factory-built wood-burning fireplaces to use Class A vent pipe. Most of these models will use an air cooled variety of Class A that has a four- to five-inch difference between the inner and outer walls.

By Colton from S. Texas on December 19, 2013
I am wanting to add another wood burning stove/heater to my house. The room I would like to put it in has no attic. The ceiling is the underside of the roof (shingled) and pitched. I am having trouble finding what I need to do with this. Can you please help?
By Collin C. - NFI Master Hearth Professional on December 20, 2013

Because you have only the roof decking to go through, a very short ceiling support box can be used, such as the DuraTech All-Fuel 11-Inch Square Cathedral Ceiling Support Box with Trim Collar - For Chimney Pipes with a 6-Inch Inner Diameter. This part will allow you to pass the chimney piping through the decking and can immediately transition to a roof flashing. I am assuming that you will be fastening some sort of finishing material to the backside of the rafters. How thick are the rafters and what is the pitch of the roof? Please advise at your convenience.

By Rodney from St. Louis, MO on December 23, 2012
I have triple wall stove pipe stainless steel, and I want to do a vertical installation. Can I use the Class A chimney pipe from the top of my stove to the top of my roof?
By Tyler M. - Fireplace Specialist on December 24, 2012

No, wood stoves are designed to use single- or double-wall stovepipe from the top of the stove to the ceiling or wall of the room where the stove is installed. At that point (ceiling or wall), you transition to double- or triple-wall Class A chimney pipe.

We have all of the necessary components for these installation. If you prefer, please fill out our
Chimney Pipe Design & Quote Form, and we can provide a quote for your installation.

By Mark from Newport, VA on December 23, 2012
Is there a chimney liner/piping that I can install that will work with any stove/insert (regardless of type - wood/pellet/gas/etc)? I would like to do this once and be done for all time.
By Tyler M. - Fireplace Specialist on December 24, 2012

The type of liner you need will depend on what kind of stove or insert you get. Generally, a 6" stainless steel liner would be needed for a wood stove or insert (installed into an existing brick/masonry fireplace), while a pellet stove would require a 3" or 4" diameter liner. A gas insert (B-vent or direct vent) would require an appropriate size and type of liner depending on the model.

By Dan from Yale, MI on September 19, 2014
How do I know what chimney diameter to use? I have a large indoor wood furnace; it has 6" coming from the unit. However, where it was installed at the last house, on occasion of high wind, it blew the smoke into the garage from the furnace. My guess is that the 6" was not enough to vent, or it did not have the velocity from too short of a stack. What do you recommend?
By eFireplaceStore on September 19, 2014

Almost every manufacturer recommends using the same diameter of chimney as the size of the flue collar on the appliance. Unless the manufacturer of your furnace specifically states otherwise, 6 inch chimney should be used. Without a doubt, a short chimney can cause drafting and back draft issues. A minimum chimney height of 15 feet is recommended for all natural vent solid fuel appliances. The measurement is generally taken from the fuel door opening on the appliance. If you would like to provide the manufacturer name and model number of the furnace, I will be happy to check into what else I can find.

By Kim from Panaca, Nevada on October 27, 2013
Are all the different brands of class A chimney pipe the same thread on the connectors? Could I use a Metal-Fab pipe and screw it into a Selkirk brand pipe or a Pro pipe?
By Tyler M. - NFI Certified Specialist on October 28, 2013

No, all brands of class A pipe have their own proprietary connections. A chimney system must use the same size diameter and brand pipe throughout.

By Andre from NY on June 14, 2013
What does the different sizes, 6", 7" and 8", mean?
By Collin C. - NFI Master Hearth Professional on June 14, 2013

Sizing of the chimney pipe will depend on the appliance. Most modern, high efficiency appliances will require a 6 inch chimney pipe, although some large models will require 7 or 8 inch. The design of each appliance will only allow a certain amount of heat escape to the chimney. High efficiency appliances release less heat. As such, a larger 7 or 8 inch chimney would become too cool by the end of the vent run, leading to condensation and creosote formation. It can also have a negative effect on drafting.

It is best to assemble a vent system based on the size of the flue collar your appliance has. Most manufacturers will specifically state what pipe brand and size to use. If you have an older appliance with no literature, measure the width of the flue collar to find out which size pipe to use.

By Ralph from PA on November 19, 2014
I have an Airjet chimney pipe. Can I use other manufacturers' single wall pipe to chimney pipe adapters?
By eFireplaceStore on November 20, 2014

Yes you can. The brand of single wall pipe is not as important as brands of double wall stovepipe or chimney pipe. Most brands of chimney will have an adapter included that will mate to the same diameter of single wall stovepipe without an issue.

By Candice from Cape Cod, MA on October 1, 2013
I am replacing my wood stove chimney that is a cement block with a metal pipe chimney. I live on the water on Cape Cod, MA. Which piping would you recommend? Do the pipes come in stainless steel? Do you recommend this for a salty air environment?
By Collin C. - NFI Master Hearth Professional on October 1, 2013

When replacing your current chimney, it would definitely be prudent to use a high quality stainless steel chimney system. The required alloy for a seaside location would be 304 stainless.

By Mike Mullen from United States on November 27, 2012
I'm considering adding a wood stove insert to my existing brick fireplace. Do I need to add chimney pipe? Or can I just exhaust to the current brick chimney?
By Collin C. - NFI Master Hearth Professional on November 28, 2012

In order for the unit to vent properly, you must use a flexible chimney liner of the proper size and route it to the bottom of the first clay flue tile. Ideally, the liner would run the entire length of the chimney, as this would greatly increase the efficiency and improve the performance of the unit. The high efficiency inserts will not operate properly without at least the minimal length of liner in position.

By marc from Michigan on November 19, 2012
Can a Duraplus Galvalume 6" elbow be used with Duraplus stainless steel pipe?
By Tyler M. - Fireplace Specialist on November 19, 2012

Yes, the DuraPlus galvalume and stainless pipe sections are interchangeable, as long as the inner diameters are the same.

By Patrick from Hayden,Al. on January 22, 2013
I just purchased a Vantage Hearth Performance Line Series 42 Inch Heat Circulating Louver Faced Wood Burning Fireplace with Full Insulation CUI-VC42LI1 and would like to know what 36",18",24" & 48" Class A Pipe will work on my fireplace.
By Collin C. - NFI Master Hearth Professional on January 22, 2013

This unit uses FMI 8DM venting components. Please visit the item page for the CUI-VC42LI1. You can then see the correct venting components by clicking the "venting components" tab on the item page.

By Terry from Ridgecrest, CA on September 21, 2014
Is class A chimney pipe zero clearance rated?
By eFireplaceStore on September 22, 2014

Unless otherwise noted by the manufacturer, Class A chimney requires 2 inches of clearance to combustibles. The clearance cannot be reduced in any way, unless authorized by the local authority having jurisdiction.

By Richard from Eagle Bridge, NY on July 14, 2014
I had a metal bestous chimney installed last year but it doesn't draft as well as I'd wished. I'd like to add another piece to the chimney. Do you have metal bestous or something that will fit, it's 8".
By eFireplaceStore on July 15, 2014

We do indeed stock the Metalbestos (now MetalBest) chimney system. If you would like to advise on the number of feet you wish to add, I will supply the correct link to the item.

By Joe from St. Paul, MN on January 14, 2013
I am looking for a chimney substitute for brick for an outdoor drying oven. The interior temperature of the oven will be 2100 to 2250 degrees, propane heated. The heating/drying process takes about 8 - 9 hours. The oven is in a stand alone shed outside. What options or products would you suggest and that are cost efficient also? I suspect I need two feet horizontal pipe with a elbow and 8 - 10 feet of stack.
By Collin C. - NFI Master Hearth Professional on January 15, 2013

Based on the temperatures the oven will achieve, I would definitely recommend using a high temperature chimney system. Do you have any idea of what diameter vent the oven will require? Will the unit be completely sealed with a combustion air inlet? Was the unit custom built of prefabricated? Please advise at your convenience.

By Tom from OH on June 19, 2013
Can I exit the chimney below grade at a 45 degree angle to the outside and up to the roof for a Class A chimney? Or does it have to be 90 degrees to the outside and in a well?
By Tyler M. - NFI Certified Specialist on June 20, 2013

Since there are no 45-degree elbows made in Class A chimney pipe, yes, you will need to run your stovepipe out the wall at a 90-degree angle and use a Class A tee to turn the pipe vertically outside the home to run up over the roof.

By Dave from Pennsylvania on January 6, 2013
I bought a house in Pennsylvania. They installed a chimney system when the home was built but never installed a stove. I just bought a stove and I am trying to install it. The chimney is all Jacks Evans pipe. I heard they went out of business. Do you know a compatible brand I can use? I am looking for the chimney pipe adapter.
By Collin C. - NFI Master Hearth Professional on January 7, 2013

After speaking to one of our distributors, I have learned that this brand of pipe was purchased by Selkirk. Apparently, they did not change the diameter or mating surfaces of the piping, so a Selkirk chimney adapter will fit the pipe. The adapter is the Selkirk DSP Double-Wall Black Stovepipe to SuperPro Factory-Built Chimney Adaptor - For Wood Burning Stoves.

The adapter can be used with both Selkirk DSP double-walled pipe or with standard single walled pipe.

By Charles from NC on November 14, 2014
Will a SuperPro adaptor/anchor plate for a factory fireplace fit a SuperVent chimney pipe?
By eFireplaceStore on November 14, 2014

The SuperPro adapter plate will work, as long as the diameter of the piping is the same. SuperVent and SuperPro have the same attachment lances. The only difference is the grade of stainless used in the construction of the products.

By Bill from Grinnell Iowa on January 15, 2013
I have some 30 year old solid pack pipe, measuring 7" inside and 11" outside diameter, that locks together. Is that pipe still made, and what is the name of it?
By Tyler M. - Fireplace Specialist on January 15, 2013

We are unable to determine whether this pipe is still available. While we do not carry a pipe with these specs, it is possible it is still available through a manufacturer that we do not sell. We apologize for this inconvenience.

By Robert from Sharon, OK on September 23, 2014
I just had a 30' by 60' x 12' pole barn built that uses "R" panel sheet metal with dual face foil insulation. I already have a wood burning stove with a 6" outlet on it that I want to use. I want to bring it out of the wall fairly high up so that I can get the most heat from the stove pipe. I am possibly going to put a magic heat in if we need it. How do I get it through the wall and not have it leak. After it goes outside do I still need class A pipe as i normal house would?
By eFireplaceStore on September 23, 2014

You would need to pass the piping through the wall with a thimble, such as the DuraTech All-Fuel Chimney Pipe Wall Thimble - For Chimney Pipes with a 6-Inch Inner Diameter. Depending on how flat the wall is on either side, you may need to fabricate a metal pedestal to help house the thimble. Once you have made your initial vertical rise inside the shop, you will need to convert to Class A chimney before passing through the wall, continuing with the Class A outside.

By Marty from TX on November 26, 2014
I have a fireplace insert made by Vermont Casting, model BC42, in which the pipe outlet inside diameter measures 8 inches and the outside ring measures 10 inches. Do you carry a brand of double wall piping that will work with this insert or that could be adapted to work?
By Chris C. on November 26, 2014

We do indeed carry the specific line of chimney pipe in which the BC42 fireplaces utilize. Please view the "Venting Components" tab on the page seen here.

By Roger on November 9, 2012
What size liner will fit a 7 square chimney flue?
on November 9, 2012

A 7" chimney flue with no obstructions will accept a 6" reline pipe with no problems. However, depending on your locality and the type of appliance that you are venting, you may need an insulation kit for the liner you are installing. These insulation kits normally add an inch to the diameter of the liner you are installing. Be sure to leave room for the insulation, if it is required. Please let us know if you have any additional questions.

By Jeffrey on November 9, 2012
I have a wood burning furnace vented to a Metlvent (Hart & Cooley) stainless steel insulated chimney that passes through the roof from the basement. The existing chimney is 7" inside diameter and is in good condition. The recommended chimney diameter for the existing furnace is 6 inches. Would it be feasible for me to line the existing chimney with a 6-inch diameter stainless steel liner to get better draft and reduce creosote build up? I am on the roof cleaning the chimney about every three weeks. I look forward to hearing from you.
on November 9, 2012

Generally, this would be a perfectly acceptable way to resize the chimney to a smaller diameter for increased performance. For durability, I would recommend a 316Ti stainless liner, rather than a 304 grade. While the 304 is usually sufficient for wood burning applications, it can have a tendency to overheat and fail prematurely when used with a furnace. To be certain there is not a problem with this, I would verify if anything is mentioned in the literature for the furnace. Most wood burning furnaces will allow a scenario such as this and cover it within the venting section of their manual. Please let me know if I can assist you with selecting product for the retrofit.

By Kyle on November 9, 2012
I am building a concrete block garage that I want to add a woodstove to. I will be installing a masonry tetra cottage thimble. How do I transition from stove pipe to chimney pipe? Should this be done before the thimble, inside the thimble, or outside before the tee? I can install a 6-inch or 8-inch inside diameter thimble.
on November 9, 2012

Typically, the transition to a chimney liner would be made just past the end of the thimble, inside the chimney flue. You would pass the stovepipe through the thimble, then into the takeoff leg of the tee. You will of course need to leave access to the underside of the tee to gain access to this area and make the connection. Please let me know if you have any technical questions. I will be happy to assist.

By Dale on November 9, 2012
I am installing a small hobby evaporator for maple syrup. The stack will be 7" stainless regular pipe. I would like to go through the wall, to a "T" for cleaning and then up approximately 9 feet. I expect the exhaust gas temperature to be 800 - 900 degrees continuously at the wall thimble. What products would you recommend for the pipe transition? And the thimble for that temp? (6" wall), and pipe? I would like to use 8" for everything and convert my 7" pipe to 8" at the wall thimble if possible.
on November 9, 2012

It is certainly possible to use an adapter from 7" to 8" before passing your chimney pipe through the wall. Traditionally, you would use single wall black stovepipe inside the building, then convert to double or triple wall Class A chimney pipe before passing through the combustible wall. I would recommend using something like our 8" DuraTech double walled chimney. It is a ceramic blanket insulated chimney pipe that can pass through the wall, utilizing a thimble to maintain proper clearance to combustibles. Please advise what ZIP code the items would need to be shipped to and I will gladly get a quote together for you.

By Dave on November 9, 2012
I have a problem with smoke seeping out the elbows of standard 6 black pipe. The elbows have to be turned from a true 90 as my wood burner is 20 away from chimney. Will these class A pipes and elbows cure this?
on November 9, 2012

Class A chimney will most likely not be an option for your installation. I suspect that your stove pipe vents up and turns 90 degrees into a brick chimney. If this is the case, you will need to continue using single walled black stovepipe in the house. If the pipe you are using now has crimped ends or has the male ends facing upwards, this could be causing the issue with smoke leakage. I highly recommend redoing the system with welded stovepipe, as it is less prone to leakage. Assembling the pipe with the male ends down will also help. Please let me know if I can assist you further.

By Bud from Scotland, CT on February 26, 2013
Will the 7' Duraplus Class A pipe connect to Metalbestes or Metalfab? I want to extend my existing chimney.
By Tyler M. - Fireplace Specialist on February 26, 2013

No. As is the case with all Class A chimney pipe, you must use the same model, size and manufacturer for each chimney component; these brands are not interchangeable. You must use the same manufacturer's pipe for your entire chimney system for proper UL listing.

By Cory from TN on July 24, 2013
I'm wanting to buy a wood burning fireplace for the new house we are constructing. The issue I'm having is the space between our engineered joists is only about 13.5". What wood burning fireplaces do you carry that have a double wall chimney that will accommodate that small space still giving the needed clearance from flammable materials?
By Tyler M. - NFI Certified Specialist on July 24, 2013

We do have a couple of models that use solid-pack class A chimney pipe with a 6" inner diameter and a 8" outer diameter. One example is the Flame Monaco XTD EPA Zero Clearance Wood Burning Fireplace.

By Brian from Laclede, Idaho on January 21, 2014
Will FMI class A pipe work with standard double wall pipe non insulated? I want class A pipe from the ceiling box up and out and standard double wall from the wood stove to the ceiling box.
By Tyler M. - NFI Certified Specialist on January 22, 2014

No, the FMI chimney pipe cannot be used in conjunction with a freestanding wood stove or with other class A pipe. It can only be used on a zero clearance woodburning fireplace. If you need a full quote for your application, please fill out our Chimney Pipe Design & Quote Form.

By Richard from Vienna, IL on November 8, 2014
Do wood stoves require 2-wall pipe or 3-wall pipe?

By eFireplaceStore on November 10, 2014

Wood stoves can use either double wall or triple wall chimney piping. In almost all cases, double wall is sufficient. However, some municipalities call for triple wall only. As such, I recommend checking with your local code office before making a material purchase.

By Michael from OR on September 9, 2014
I need: MBS 8T EL30 8" Metalbestos 30 Degree Offset & Return; MBS 8UT 12 8" x 1' Chimney Pipe; MBS 8T FC 8" Metalbestos Finish Collar; MBB 8DSP CPA 8" Chimney Pipe Adaptor DW - Class A. Do you have these items?
By eFireplaceStore on September 10, 2014

The Metalbestos product line has been revised to the new MetalBest product line. Luckily, the attachment hems and diameters did not change, so the parts from each line can be used with one another. New part numbers are below:

8T-EL30 KIT - 30 Degree Offset and Return Elbows
8UT-12 - 12 inch length
8T-FC - Finishing Collar
8DSP-CPA - DSP Chimney Adapter