A chimney is a mandatory attribute of any stove, thanks to which the resulting combustion products are removed from the heating system. The chimney is most often made of a metal pipe. It creates a draft, with the help of which all gases escape along with smoke.
Chimney requirements
You can install a metal chimney for a stove with your own hands, the main thing is to do it correctly, otherwise, due to incorrect calculations, the load on the heating system will increase, the room will become smoky, etc.
Main characteristics of any chimney:
- form;
- material;
- size.
The first thing you should pay attention to when buying a chimney pipe is its shape. Experts recommend using cylindrical pipes; they are better than others for removing waste gases and smoke.
Many owners of fireplaces and stoves are wondering how to clean a chimney? And this is no coincidence, because a decrease in draft can lead to failure of the chimney and fire. Let's look into this issue.
Important! The chimney for the stove should have as few corners, sharp transitions and obstacles as possible. Otherwise, a lot of soot and ash will settle on the walls of the pipe.
The material from which the chimney is made is no less important. If we are talking about a highly acidic environment, then it is best to use stainless steel pipes with molybdenum. A stove chimney can also be made of brick, but the most popular material is alloy steel. We previously wrote about and advised you to bookmark the article.
The size of the chimney directly depends on the size of the heating structure (stove). To correctly determine the height of a structure, you need to seek help from building code documents. Errors in calculations lead to a decrease in draft and the appearance of traces of soot in the room. In order not to make a mistake with the diameter and length of the pipes, you can use a suitable ready-made project with dimensions from the Internet.
Basic requirements for metal chimneys:
- Pipes must be well insulated.
- Before installing the chimney, you need to make the correct calculations and prepare a project.
Compliance with these rules will allow the chimney to function without such consequences as smoke in the room, soot deposition, carbon monoxide inflow, etc.
Installation rules
- If the chimney pipe rises more than one and a half meters above the roof, then it must be additionally secured with brackets or braces.
- The height of the metal pipe from the furnace to the head must be at least 5 m.
- To remove condensate, special plugs are installed in the chimney.
- In some heating devices, the temperature of the exhaust gases is very high, so the ceiling surface must be additionally insulated. The craftsmen also recommend using special parts during installation, for example, an insulated passage through the ceiling.
- The chimney must extend at least half a meter beyond the roof.
- When installing a chimney pipe, it is unacceptable to “narrow” its diameter.
- Horizontal sections of metal pipe should not be more than 100 cm in length.
- If the pipeline is laid near structures made of flammable materials, then it should heat them by no more than 50 degrees Celsius.
- The chimney must be located at a safe distance from electrical wiring, gas pipelines and flammable building materials.
Read more about it on our portal.
Tools and materials
You can install a metal chimney for a stove yourself; for this you need to prepare the following materials and tools:
- metal elbow;
- connecting elbow;
- metal pipe;
- sealant (We recommend reading the material about);
- spark arrester;
- thermal insulation;
- brackets or other fastening elements;
- anti-spill canopy;
- tee with condensate drainage, etc.
Note: There are two types of tee for collecting condensate and cleaning the chimney: 90 and 45 degrees. It is usually sold with a special plug. It can be blind or with a condensate drain.
Parts for installing a metal chimney - elbow, tee, plugs, etc.
Installation stages
The stove chimney, and in this case we will talk about installing a pipe for a potbelly stove of standard sizes, is mounted as follows:
- The first piece of metal pipe is fixed in the chimney opening in the stove using sealant.
- The knee is extended, moving up to the ceiling or window.
Important! The pipe must be secured to the wall with brackets every two meters.
- Having reached the ceiling, a hole of the required size is cut and the thermal insulation is removed. The size of the passage must be at least 70 mm larger than the diameter of the pipe.
- The pipe is brought out through the passage glass and fixed at the attachment point with the external chimney.
Advice! The joints of elbows, pipes and tees are additionally secured with clamps. After completion of the work, they are additionally sealed.
- Next, attach a tee to drain condensate.
Advice! If the chimney will be discharged through a window, then a pass-through glass is installed in the glass hole.
- The external chimney is covered with bitumen and provides adequate thermal insulation.
- A spark arrestor is attached to the surface of the pipe, popularly called a “mushroom”. It protects the chimney not only from flying sparks, but also from precipitation and small debris.
- At the end of the work, an umbrella is installed on the chimney.
- Places of pipes that may be susceptible to corrosion are treated with heat-resistant paint.
- After all installation work on installing a metal chimney has been completed, a test firing of the furnace is carried out. Check the tightness of the structure and the heating level.
Important! When testing a stove with a newly installed metal pipe chimney, a burning smell or light smoke may appear. This is due to crystallization of the sealant composition and evaporation of oil from the surface of the pipes.
The efficient operation of a chimney for a wood-burning stove and other types of heating appliances depends not only on correct installation and calculations. The chimney needs constant maintenance. It is necessary to regularly monitor the condition of the pipes for burnouts, rust, corrosion, and clean them. During operation of the furnace, traces of soot and soot remain on the inner surface of the pipes, which make the cross-sectional diameter of the pipeline narrower. In addition to natural combustion products, traces of plastic waste may settle there. Sometimes the chimney becomes clogged due to the appearance of a wasp's nest inside the pipe, etc. Experts recommend carrying out cleaning work at least two or three times during the heating season.
For cleaning you can use:
- aspen firewood - burning aspen quickly removes soot;
- flexible thick cable for hard-to-reach places;
- burning special chemical compounds together with fuel, etc.
Video: DIY metal chimney installation
You can install a metal chimney for a stove with your own hands. To avoid unpleasant consequences, you need to strictly follow the instructions and not be creative.
Any autonomous device for heating rooms requires a device for removing toxic products of fuel combustion. Stove chimneys can have different designs, heights or diameters, and during their construction a number of technological nuances and features must be taken into account.
The construction of a chimney is the most important stage in the construction of a brick oven, the correct execution of which determines not only the efficiency of its operation, but also the well-being of the residents of the house.
The chimney is the most important part of the loop system, the correct operation of which directly determines the performance and efficiency of the stove. The operating cycle of such a system can be described as follows:
- Fuel combustion occurs in the firebox.
- During the combustion process, oxygen is processed, and corrosive gases are heated and removed through the chimney to the outside.
- When combustion products are removed from the firebox, an area of low pressure is formed, into which new portions of oxygen are drawn through the same chimney.
- The process is repeated again and again, until the fuel is completely burned.
Failure to comply with the chimney installation technology can cause a cycle disruption and provoke some unpleasant consequences:
- Irrational fuel consumption.
- Deterioration of heat transfer of the furnace.
- Increased fire hazard.
- Penetration of dangerous carbon monoxide into the living space.
Varieties
There are several types of chimneys. They are classified depending on their location relative to the furnace itself:
A chimney is an essential element of any heating system that emits combustion products during operation. A draft is created in the pipe, on the one hand providing an influx of oxygen into the firebox, which is necessary to maintain the combustion process, and on the other hand, facilitating the removal of smoke and gases to the outside. In long-burning stoves, the installation and operation of the chimney is carried out according to standard rules, although it has some features.
Of the variety of metal ovens, installations with a long combustion function (convection ovens) are in great demand and popularity. Such ovens are easy to use and very economical. They are equally well suited for small country houses, multi-storey private houses, workshops, warehouses, etc.
The main features of such furnaces include:
- Increased volume of the firebox, accommodating a large amount of firewood.
- Dividing the firebox into two chambers that perform different functions. Gas is burned in one, wood is smoldering in the other.
- The presence of a special bumper inside the firebox that prevents the open flame from engulfing the chimney.
The combustion process itself is radically different from the operation of an ordinary metal furnace. The firewood is ignited in the upper part of the firebox, and air is supplied here. The supply volume is regulated by a damper. The fire spreads downward, and the intensity of the flame cannot be called strong; the process is more like smoldering.
As the wood smolders, pyrolysis gas is also released, which moves into a separate chamber of the firebox, mixes with air and also burns, further increasing the efficiency of the installation.
During operation of a long-burning stove, less heat is generated, allowing the room temperature to be maintained at the same level. Much less firewood is consumed, and the combustion products entering the chimney have a low concentration of harmful substances.
Buleryan stove: advantages and disadvantages
Bullerjan is one of the types of long-burning stoves that operates on the principle of convection.
The design was developed by Canadian inventor Eric Darnell in 1975, after which the rights to the patent were purchased by German businessmen who launched serial production of stoves under this brand.
The stove combines the functionality of a standard wood-burning firebox, air heater and gas generator. Buleryan is able to work in two modes:
- Kindling. More air is supplied to burning wood, which contributes to its rapid combustion and accelerated heating of the room.
- Gasification. The oxygen supply is reduced to a minimum. The firewood gradually smolders, and the room warms up more slowly. In this operating mode, one stack of firewood will be enough for 10-12 hours of continuous operation.
In everyday life in any province, stove makers offer several types of chimneys:
Stainless steel chimneys
- Chimneys made of ceramics
- Chimneys made of brickwork
- Chimneys made of asbestos pipes
For consumers, stainless steel chimneys for stoves are the most inexpensive, reliable and convenient solution for smoke removal. If you look at asbestos pipes, their only advantage is the price. And there are a lot of disadvantages, firstly: asbestos is harmful to health; at high temperatures, harmful substances are released. Secondly, these pipes are not intended for smoke removal; it is very difficult to make a chimney of a non-linear design. Thirdly, they are not durable.
Ceramic chimneys are extremely expensive and durable, and for such a chimney it is necessary to pour a special foundation, the weight of one block is more than 25 kg, and there can be more than five dozen of them in the design, such a load will be a big problem for the floor. A brick chimney is also not a cheap solution; the overall structure is heavy due to the complexity of the chimney; problems often arise when lighting the stove.
Stainless steel chimneys for stoves features
The main advantages of chimneys made of stainless steel:
- Large selection of metals for the chimney - no need to overpay for the material if you do not need a chimney under a large thermal and chemical load.
- more than 30 manufactured elements will allow you to assemble a chimney of any design
- the chimney structure for the stove is lightweight, no additional foundations are needed
- a stainless steel stove chimney is much cheaper than a brick and ceramic one.
The efficiency of heating stoves and other similar devices largely depends on the design chimney in the house.
Stove chimney pipe designed to remove volatile and gaseous combustion products from the firebox and create draft to ensure the combustion process.
Until relatively recently, all chimney pipes were made either from brick, or from asbestos-cement pipes, or from black non-galvanized metal.
The thing is that when the temperature of the exhaust gases exceeded 100 degrees C, zinc began to evaporate into the room, and its fumes are harmful to health. That’s why they used non-galvanized metal, covering it on the outside with beautiful silver.
Today, chimneys are built from a variety of materials, and each of them has its own pros and cons. So let's try to figure out which pipe to choose for the chimney of your house so that it serves faithfully for decades.
Asbestos cement chimney pipe
Asbestos-cement pipes have been widely used since the middle of the last century. They were cheap, easy to produce, and there was plenty of natural asbestos in the country. Moreover, such pipes could be used without any preliminary insulation for a wide variety of agricultural needs. But they were never intended for arranging chimneys.
During the times of reclamation in rural areas, asbestos-cement pipes were not uncommon, and during the period of mass construction of private houses, they came into use as chimney pipes. 
Many opponents of this implementation immediately appeared - first of all, environmentalists who argued that asbestos cement releases many bad compounds into the environment.
Although, according to scientists, asphalt on the road is even more carcinogenic.
But, nevertheless, even the roofs of buildings today are covered with a variety of expensive roofings instead of cheap and durable asbestos.
All these fears and myths have little to do with chimneys made from asbestos-cement pipes.
And at the same time, they are not at all safe - this material was never designed for high temperatures, and can burst already at 300 degrees C. Therefore, if you place them, then not at the stove itself - but as close to the roof as possible, where The smoke is already a little cooled.
To prevent the danger of flying fragments and accidental fire (God forbid) in the hot part of the pipe, as well as in uncontrolled places (attic), it is better to wrap the asbestos-cement pipe with a sheet iron bandage. 
There is also another point. Soot forms in any chimney, but the smoother its walls, the less soot is retained on them.
But asbestos-cement pipes have never been smooth, and a lot of soot accumulates on them. And it’s easy for it to catch fire – any stove maker knows this.
Moreover, if the soot catches fire inside an asbestos-cement pipe, it can burst due to temperature. Is it dangerous.
Asbestos-cement pipes are also severely damaged by condensation. Condensate is an aggressive medium consisting of a mixture of combustion oxides and a very small amount of moisture.
Moreover, the oxides contain a good percentage of hydrochloric acid, which even destroys bricks, but asbestos also absorbs it, transferring all this to the building in the form of unsightly stains with the same unpleasant odor.
This means that if you decide to use an asbestos-cement pipe for your chimney, clean it as often as possible.
True, cleaning such pipes is difficult - inspection windows cannot be made in such pipes.
Brick pipe
The construction of a brick chimney has a long history.
Such a pipe is laid out of red stove brick at the same time as the stove. A competent stove maker knows exactly which brick to choose for the stove, even different ones inside and outside, which brick is needed for the chimney inside the attic, and which one is needed for the outside of the chimney on the street. 
The inside of the chimney should not be corroded by condensation, and the outside should not be washed away by rain or crack due to temperature changes. Therefore, overheated, underheated and wet bricks should be clearly distinguished.
A pipe made of this material requires periodic repair. In addition, to install a brick pipe with your own hands, you need to use a special solution that is resistant to the combustion process, but at the same time is plastic and heat-resistant. 
Since the weight of a brick pipe is very significant, the entire stove-pipe structure is usually one piece and placed on a separate foundation not connected to the house.
Brick chimneys and chimneys are also installed inside the brickwork of the building wall. 
Place chimneys and chimneys with bandages on lime or cement-lime mortar inside the house, and above the roof on cement mortar.
According to SNiP, wall channels are made of high quality red solid brick, with a seam no thicker than 10 mm. The inner surface of the channel is not plastered.
However, no matter how well such brickwork is made, the inner surface of a brick chimney is rough and it will still become covered with soot over time. In any uneven area of the chimney, soot accumulates more intensely.
The wall with the chimney duct inside is almost constantly wet from condensation. 
Aggressive acidic condensate destroys the brickwork, the brick crumbles and sometimes even collapses inside the channel and narrows its cross-section.
To significantly increase the service life of the chimney, it is necessary to periodically clean it at least once every six months.
The internal cross-section of a brick chimney has a rectangular cross-section, so when gases move in the corners, turbulence occurs, which reduces draft.
Therefore, an asbestos-cement or steel pipe is sometimes placed in the internal channel.
The main disadvantages of a brick pipe are weight, size, difficulty of repair and replacement.
But the aesthetics, fire safety and durability of brick chimneys exceed any of their shortcomings.
Ceramic stove pipe
Ceramic chimneys are also a modular system of fully prefabricated elements.
In the simplest cases, they are a regular ceramic pipe, but it is considered more appropriate to use sandwich structures that provide safe operating conditions.
Heat-resistant ceramics are acid-resistant and durable. 
Some manufacturers claim a guaranteed service life of up to 30 years, and an expected service life of up to 100 years.
The inner surface of the ceramic is coated with a special heat-resistant glaze, which makes it absolutely smooth.
This prevents the formation of turbulent vortices, the gas flow passes in a calm laminar flow. Soot does not stick to the smooth ceramic surface. 
The chimney of such pipes is the most durable. It is not afraid of prolonged intense heating, chemical aggressive environments, or corrosion. Its inner surface is very smooth, almost no soot or ash lingers in it, and as a result, maintenance of the pipes is minimal. 
Ceramics is also an excellent heat-absorbing material, and in combination with the expanded clay concrete box in which it is hidden, the outer surface of the chimney ultimately does not heat up at all. And this is a complete guarantee that your house will never fall into that sad statistics of houses that burn due to chimneys!
These elements have a significant total weight, so the ceramic chimney pipe is installed on a separate foundation.
Carrying out brickwork requires considerable time, and installation of a chimney with a ceramic pipe can be carried out in a short time.
Ceramic pipes are expensive and practical.
Metal chimney
Metal chimneys are almost always made of stainless steel. They are an almost modular system of straight sections and shaped elements: adapters, bends, tees, umbrellas.
Such systems can be either embedded inside brick channels or mounted separately.
The stainless steel used is heat-resistant and acid-resistant, and condensation cannot corrode it. 
Stainless steel is the most suitable material in terms of overheating, soot and getting wet. This material can even heat up to 500 degrees C – and it will not melt yet.
Soot does not accumulate on the smooth inner surface of the chimney.
Thus, due to the smooth, soot-free surface and stable cross-section, stable aerodynamic characteristics of the passage of exhaust gases are ensured. 
Single-walled metal chimneys consist of one layer of stainless steel, while double-walled ones consist of two layers of metal with mineral (most often basalt) wool placed between them.
These are sandwich systems. In this case, the outer surface heats up minimally, heat is retained perfectly throughout the entire chimney, and therefore condensation almost does not form on the inner surface. 
Sandwich pipes are very technologically advanced and have been used quite often lately, especially for baths. The only thing is that when purchasing, you need to carefully check the quality of the steel, because there are many cases of pipes burning through and fires for this reason.
Sometimes, during repair or restoration work, a metal pipe is placed inside brick channels. This is called a "sleeve".
The low weight allows these chimneys to be installed without a special foundation. 
There are also corrugated pipes. They are used exclusively to create turns and bends in the chimney, but almost never as the main pipe. But they are irreplaceable if there is a beam just above the stove and all that remains is to go around it. For more, they do not yet have sufficient anti-corrosion or thermal insulation qualities.
It should be noted that there are metal chimneys that are not made of stainless steel. For example, for sauna stoves, some manufacturers offer thick-walled pipes made of low-alloy steel.
And when constructing sauna stoves, craftsmen quite often use cast iron chimneys from sewer pipes.
Concrete chimney pipes
The main advantage of such pipes is the low cost of the material, durability, maintainability and lack of seams. And you can make the pipes themselves at home using sliding formwork.
The composition of the mixture is as follows: three parts sand, water and one part Portland cement M400. The concrete turns out to be quite hard. It is better to make the pipes monolithic, and there will be very little soot.
The only drawback of such pipes is their heaviness. This can be corrected if expanded clay is used in the composition.
Vermiculite pipes
Vermiculite pipes are a new wave of popularity in the construction market. Condensation does not form inside such pipes at all, and therefore they very rarely need to be cleaned.
In its composition, vermiculite is close to aerated concrete, and is just as light, but it does not absorb moisture at all, tolerates high temperatures well and has good resistance to any physical influences.
Chimney pipe head
Many people saw something like an umbrella, a mushroom or a hat at the end of the pipe. This part of the chimney is called the head; more modern terminology refers to this structure as a spark arrester or deflector.
The head of the chimney can perform one or more functions - it protects from precipitation, extinguishes sparks flying from the chimney, improves the draft of the stove, and sometimes it is a very beautiful decoration.
The head of the chimney can be structurally simple - in the form of an umbrella, or it can have a complex design to protect against wind blowing and improve overall draft; the appearance in this case can have a different shape.
Chimney draft
There are special devices that measure chimney draft in pascals (the difference in pressure in sections of the chimney), although they are very expensive, so in most cases, rather trivial methods are used to determine draft:
- the traction force is determined by the deflection of a sheet of paper (in most cases, toilet paper is ideal);
- the direction of draft is determined by the direction of the smoke from a lit cigarette.
The sufficiency of traction can also be determined visually:
- Smoke in the room - reverse draft;
- The flame is bright white, there may be a roar in the chimney - the draft is too strong;
- Flame with dark stripes, red – insufficient draft;
- The flame is golden yellow – the draft is normal. 
What does chimney draft depend on:
- insufficient height will lead to a decrease in traction, and in the case of excess, then, on the contrary, to an excessive increase. If you are not going to carry out an accurate physical and mathematical calculation, you should focus on a length of at least 4.5 meters.
- The cross-sectional shape directly affects the aerodynamic characteristics of the chimney: for example, in the case of a rectangular or square cross-section, we get additional turbulence in the corners that impede the overall flow, which is not observed in round analogues.
- Placing the chimney mainly in the interior of the building will allow you not only to increase the heating capacity of the entire heating system, but will also make it possible to maintain constant good draft (even in frosty times). 
At the same time, placing the chimney outside the building requires it to warm up for a longer time and, as a result, will cause a decrease in draft.
- Too small cross-sectional area sizes when releasing a large volume of combustion products will not create the required thrust. This rule is exactly the opposite: too large a cross-sectional area with small volumes of combustion products will lead to the fact that all the heat will “fly out into the chimney”. Installing chimney pipes of different diameters in different sections of the chimney will not only lead to unpredictable draft behavior, but will also allow the formation of soot and other deposits. 
- It is best to place the chimney pipe close to the ridge of the roof, but here certain conditions must be observed: if the pipe is located at a distance of 1.5 meters from the ridge, then the head should rise at least half a meter. If the distance between the ridge and the cap is in the range from 1.5 to 3 meters, then we place the chimney flush with the ridge. When the distance exceeds 3 meters, in this case the head should be located on a line drawn at an angle of 10 degrees from the ridge of the roof downwards. Incorrect location of the chimney in relation to the ridge of the roof can lead to weakening of draft in a certain wind direction. 
- The chimney draft also depends on the smoothness of the chimney walls and the presence of sharp turns.
- The shape and dimensions of the pipe head also affect the draft. When assembling and choosing an umbrella, there is a significant danger of “miscalculating” the dimensions and, as a result, getting backdraft, for example, if the umbrella is too large and lowered too low. If you install a factory stainless steel chimney hood, no problems will arise - all the necessary parameters have already been calculated by engineers
- Atmospheric phenomena, air pressure, temperature, humidity, the presence of wind - all this naturally affects the draft in the chimney.
We can adjust the draft manually using a gate.
A damper is a damper, the intended use of which is intended not only to regulate the draft force, but also to protect the room from fire. One damper is installed in the chimney duct, the other, as a rule, is mounted either in the stove itself or in its door. Thus, by varying their position, we can adjust the traction force, which is an important advantage.
A good stove and chimney are the key to warmth and comfort in the house, because with its help you can easily heat even a very large house.
However, not everyone can correctly assemble a stove and pipe with their own hands, which is why in order to do such work, you must have certain knowledge and experience. Laying a chimney with your own hands is not at all difficult, you just need to have all the necessary materials and follow the instructions.