I have been burning wood to heat my home since 1982. The information written in this article is from my experience over these years, and from the research, I have done to ensure my home is safe while heating with a wood fire.
Is a
Since 1988, the EPA (Environmental Protection Agency) has played a part in how wood burning stoves are manufactured. These rules have reduced the number of pollutants (or Particulate Matter) a stove puts out and have a slight effect on the safety of the wood burner.
The more important agency that gives guidance for the
Wood Stove Safety
NFPA 211 is the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances and has been updated in 2019. This standard covers the safe installation of wood burning stoves and many items that are related to the stove, especially chimneys. Anyone can view this document for free, but remember, it is not a fun, exciting read!
The highlights of the Standard:
- Chimney type, size requirements, installation recommendations, and height above the
roof . - Floor area and materials near the stove.
- Wall area and materials near (behind) the stove.
The bulk of the 68-page document has illustrations, descriptions, and tables dealing specifically with chimneys. The reason for this is that chimneys are where most fires occur in a wood burning stove system. The stove and the area around the stove are rarely where a house fire begins when a fire does originate from a wood stove system.
Fires in Homes
Looking at statistics, the most common cause of fires in homes (according to an NFPA report 2012-2016) was home cooking accidents. The second leading cause at 15% of home fires was home heating appliances. This includes gas and propane furnaces, space heaters, and solid fuel burning appliances (which are wood burning stoves).
Wood burning stoves are only a portion of this statistic, and again the fire is generally found to start in the chimney. Why is this and is there anything that can be done about it?
How Wood burning Stoves Work
The first wood burning stove I saw was a home-made version that had steel pipes for air coming out the side and copper pipes for heating water running in the back of it. It was not much to look at, but it sure did work well. The owner was heating his home (to about 80 degrees) and preheating water at the same time.
He was doing this with a fairly small amount of wood. This was possible because of the very small amount of air that was being used to feed the fire. Instead of having the doors open to watch the fire (as in a fireplace), the doors sealed shut, and the air to feed the fire was controlled by a valve (actually a large water valve).
This was a great start, but next, we learned to draw the heat from the stove by adding air chambers and fans to this new household appliance. The looks also improved and wood burning stoves started appearing in family rooms.
Creosote
What we soon found out was that reducing the air flow into the stove had a negative e
The tar-like substance would eventually collect and build up to a point where it would clog the chimney. It could reduce the inside diameter of the chimney to a point where the smoke would back up in the wood burning stove and enter the home.
Cleaning a Chimney
At this point the chimney requires cleaning. A do it yourself homeowner can clean the chimney if they can safely get to the top of the stove pipe. You must also have the correct tools such as a chimney brush (that fits the exact size of your chimney pipe) and fiberglass rods that reach the entire chimney length.
If you are not 100% sure of how to clean and inspect a chimney, my recommendation would be to hire a reputable chimney cleaning company to complete this job for you. As mentioned earlier, the chimney is the primary location for fires in homes with wood burning stoves. Maintaining the chimney correctly is crucial to the safety of the wood burning system and the safety of your home in general.
Chimneys
Since the chimney is the location where fire originates in wood burning systems, let’s take a moment to look at the different types of chimneys.
Masonry
Masonry chimneys look great and work well for wood burning stoves. Masonry chimneys are constructed with a glazed tile flue liner, which is the inside “pipe” that the smoke travels up. This flue is designed for the high heat of a fire but must remain intact and not have cracks or breaks in the material.
The next layer of the chimney is made of cement blocks either exactly the same or similar to a block foundation for a house. This cement block is covered by brick, which adds the finish look and weather protection for the system. The chimney crown sets on top of the chimney and prevents water from entering the chimney system.
The extreme heat from a chimney fire (creosote burning out of control) can cause damage to the flue liner that could
Steel Lined Chimneys
There are two types of steel lined chimneys. Double wall and triple wall. A double wall chimney typically has a stainless steel inner and outer walls with a layer of high-temperature insulation in between. Double wall chimney pipe is designed to withstand temperatures of up to 2300 degrees F. This means a typical chimney fire can burn inside a double wall chimney, and not harm the walls surrounding the chimney pipe.
That does not mean it is recommended to regularly ignite a fire in a double wall chimney. The high heat of a chimney fire will eventually break down portions of even the best double wall chimney. Connections, turns, and caps would be the first places for a failure to occur after multiple chimney fires.
Triple wall chimneys are also popular and are used extensively for wood burning stoves. Instead of insulation between the inner and outer walls, a third wall is added thus the name triple wall. The air space between the walls insulate the inner flue from the outer wall of the chimney pipe.
Depending on the manufacturer and size, triple wall chimney will be rated as high as 1900 degrees F. Again, this does not mean you can burn out the creosote in the chimney time and again. Chimneys are usually installed between the inside walls of a home. The studs and drywall should be at the recommended distance from the pipe, but if the chimney fails, the walls may be exposed to excessive heat, smoke, or direct fire.
In closing, wood burning stoves built by reputable manufacturers are designed to do a specific task. Heat an area as required and exhaust
Additional Questions
Does a wood burning stove increase insurance premiums? A
Is a wood burning stove more efficient than a pellet burning stove? Typically the answer is yes the wood burning stove is more efficient if you are inquiring about the cost of wood vs. the cost of pellets. There are other items that must be factored in such as how often you load (fill) the stove and how much time you spend cleaning the stove.