Fastening of chimneys made of stainless steel. How to assemble a chimney

Stainless steel is a fairly popular product in the modern construction market. Previously, the material for their production was brick. And today chimneys are still in demand. They are necessary where there are individual heating boilers and fireplaces.

Note: The most popular and in demand are chimneys made of stainless steel and ceramics.

The latter, according to user reviews, are extremely expensive. Therefore, they are not yet very common. But stainless steel chimneys are an excellent and inexpensive alternative. They meet modern requirements for efficiency, aesthetics, environmental friendliness, compactness and ease of maintenance. Structures made from such steel are resistant to temperature changes, attractive in cost, and easy to install.

Steel chimneys have significant advantages over their analogues. This:

  • strength and durability;
  • resistance to corrosion and condensation;
  • can be used for a fireplace and for any other stoves and boilers;
  • the material is characterized by increased smoothness, so soot practically does not settle on the walls;
  • low heat capacity;
  • modular design, allowing you to build a system of any configuration from stainless steel chimney elements;
  • there is no need for burning before kindling.

Stainless steel chimneys will be the optimal solution for those who are looking for an inexpensive, fast, simple and universal way to ensure the effective removal of combustion products into the environment. Stainless steel products mounted on fireplaces, solid fuel and gas boilers are practically no different from each other. But the chimney for gas equipment can be selected less carefully, because there are no visible combustion products in it. But during the operation of fireplaces and solid fuel boilers, soot is formed, clogging the flow area of ​​the steel pipe.

Structural solution of chimneys

According to their design, stainless steel chimneys are divided into single-wall and double-wall. The latter are often called sandwiches. Single-wall products are used as a complement to existing brick channels. They will protect the chimney from the aggressive effects of condensation, which is a by-product of the operation of heating equipment. Such products are used when installing a duct inside a heated room, and also as an insert into an existing brick chimney for a gas or fireplace or stove.

Double-walled or sandwich structures are widely used for arranging exhaust gas exhaust systems. These stainless steel chimney elements are insulated and can therefore be installed outdoors. Their basis is insulated pipes: internal and external, acting as a casing. Between them is laid a 30-35 cm layer of basalt mineral wool, which has a low thermal conductivity coefficient and can withstand high temperatures up to 1000 0 C. Such properties minimize the likelihood of aggressive condensation. Thanks to the presence of a thermal insulation layer, the temperature of the flue gases remains very high up to the highest point of the network, which is the key to efficient draft in winter.


Stainless steel chimney elements can be made in the form of segmental rings, giving the system increased strength and rigidity. It also centers steel pipes together and practically does not conduct heat. The laying of mineral insulation is carried out at the stage of production of stainless steel chimneys, so the person who bought the sandwich structure will only have to install it. According to consumer reviews, such steel devices are durable and fireproof.

Do-it-yourself preparation for installation of steel sandwich chimneys

Note: Stainless steel chimneys for heating boilers and fireplaces can be easily installed with your own hands.

But for this you need to have the appropriate materials and tools. But first, you should approach the choice of steel pipes with extreme care, because the efficiency and durability of the structure will depend on their quality. Read reviews, get acquainted with the materials used in the production of a stainless steel chimney. Such information will allow you to make the right choice of sandwich structure.


Now we provide ourselves with the necessary materials and tools:

  1. All relevant elements of the chimney are made of stainless steel (crimp clamps, adapters, roofs, rosettes, elbows, plugs, trenches, tees, plugs and other materials).
  2. Wall brackets.
  3. Marker.
  4. Fire resistant sealant.
  5. Galvanized steel sheet.
  6. Sealed couplings (if desired for high pressure systems).
  7. Fasteners.

All stainless steel chimney elements are purchased as a set, ensuring perfect compatibility of materials and components.


In order to carry out the installation of a sandwich steel system as quickly as possible, you should carefully prepare. Assembling a stainless steel chimney involves installing a special pipe, which will ensure the passage of pipes through the ceiling. Initially, this steel element is covered with a layer of basalt fiber and special mastic, resistant to fire, and the insulation is placed inside the pipe, near the walls.

We mark the area of ​​the ceiling where the stainless steel will be installed. Please note that the pipe is covered with a layer of insulation, so add a small margin, including to the air gap. The last part of the internal preparatory work will be the installation of pipe protection.


Chimney passage through the ceiling
Chimney in the ceiling

Now, having installed a stainless steel chimney, it’s time to move on to the roof, where a special trim is installed. To do this, measure the inner and outer sides, taking into account the angle of the roof slope, and cut a hole. This action is best done from the inside. Take a sheet of galvanized steel, cut a hole in it for the pipe and secure it to the roof. When working, make sure that there are no seams at the separation level on the sandwich pipe.


Installation work

Now you can install the stainless steel sandwich chimney itself. This installation is somewhat similar to the assembly of a construction set. You need to move from the bottom node, that is, from the heating boiler or fireplace upward:

  1. Using a corrugation, we connect the boiler outlet pipe and the stainless steel chimney pipe. Leave the area near the heating equipment uninsulated. No matter how high-quality the pipe material is, it should be understood that the area near the stove itself will heat up to very high temperatures. That is, over time it will simply burn out.
  2. All internal pipes are inserted sequentially into each other with narrower ends. Thanks to this, condensation formed in the chimney for a fireplace or boiler will not fall into the seams, but will simply flow down.
  3. When all sections of the pipe have been assembled, the tees should be secured using brackets. All existing joints are sealed with clamps, which are tightened with bolts and nuts.
  4. It is installed on the top of the structure, protecting the stainless steel chimneys and the heating system itself from moisture from the outside. It will also contribute to the effective removal of exhaust gases even in strong gusts of wind.
  5. Remove the protective film from all pipes and treat them with sealant.

Having completed all the work and tested the system, you can sit down with a clear conscience and write your review about how easily and simply you can install the exhaust gas exhaust system with your own hands.

Schemes of external and internal chimneys



The installation of any heating device or structure operating on solid, liquid or gaseous fuel, a stove, fireplace or boiler, will require the mandatory installation of a waste combustion product removal system. Not so long ago there was no particular alternative - it was necessary to erect a brick structure or resort to the use of asbestos-cement pipes, which have many more disadvantages than advantages. Currently, the situation has changed dramatically - a stainless steel chimney shows excellent versatility.

In skillful hands, a set of stainless steel parts turns into a universal tool, making it possible to quickly install a chimney system that fully meets all the requirements of current standards and safety requirements. In addition, the overall cost of installing a chimney, even with the seemingly expensive components, will always be more attractive than other options. With a competent approach and knowledge basic principles installation, assembling such a system is quite a feasible task for any home owner.

First of all, a few words about what a set of parts for assembling a stainless steel chimney is.

There are three options:

  • Components made of single-layer material, with a thickness of 0.6 to 2 mm, the so-called mono systems. They are certainly cheaper, but their scope of application is significantly limited. They are used only inside an insulated room, since a large temperature difference between the outside and inside the pipe will lead to absolutely unnecessary excessive consumption of energy carriers, to the abundant formation of condensation in the cavity, will affect the overall performance and durability of the entire heating system. Their only advantage is that indoors they are often used as secondary heat sources - for example, tanks for heating water or external liquid or air heat exchangers can be mounted to them.
  • Corrugated stainless steel parts - they are used to create curved transitions, for example, from the heating device itself to the rigid section of the chimney. However, they do not always have the required strength and heat resistance, and often inspectors of regulatory authorities simply refuse to approve projects using corrugation.
  • The most versatile - components from the category sandwich tube, in which a layer of fireproof material with high performance is laid between the inner and outer stainless coating thermal insulation - usually, this is basalt mineral wool. Such elements can be safely used for both internal and external installation of the chimney.

The next question is the grade of stainless steel. The metallic sheen of all parts is almost the same, but the performance characteristics can vary significantly. Therefore, when choosing, you should definitely pay attention to the product labeling:

  • Steel grade 430 is used for parts that are least susceptible to aggressive influences. As a rule, external casings are made from it - the surrounding humid atmosphere is not dangerous for it.
  • 409 steel – optimally suited for appliances running on solid fuel (fireplaces, stoves).
  • Steel 316 – enriched with inclusions of nickel and molybdenum. It boosts her heat resistance and resistance to chemical (acid) attack. If you need a chimney for a gas boiler, then this will be the right choice.
  • Steel grade 304 is largely the same as 316, but the content is alloyed shih the additives in it are below. In principle, it can be a replacement for an analogue, with the advantage of a lower price.
  • Marks 316 i and 321 are the most versatile. The temperature limit of their operation is about 850ºC, and this is combined with high acid resistance and excellent ductility.
  • Stainless steel 310S is the most “elite” material, which, along with all other positive qualities, is distinguished by its resistance to temperatures up to 1000ºC.

The range of manufactured stainless steel chimney parts is very diverse and can satisfy the needs of almost any designed system.

  • Straight sections with a length from 330 to 1000 mm. All of them have a special socket connection that does not require any additional elements.
  • Elbow (bend) 45º, used when it is necessary to change the direction of the chimney on vertical or inclined sections.
  • 90º bends - as a rule, are used to transition from a short horizontal section at the heating device to the main part of the chimney pipe.
  • Tees at an angle of 45 or 87º - are installed at the installation site of the condensate collector or, in the case of installing two devices, when they are connected to a single chimney system (separate approval from regulatory authorities is required).
  • Chimney inspection elements - designed for regular monitoring and cleaning of the system.
  • Condensate collector - installed in the lower part of the main vertical section and serves to regularly clear the chimney of accumulated moisture.
  • Elements of the upper part of the chimney - spark arrester, cap, waterproofing skirt.
  • You can also purchase special elements for passing through a wall, interfloor ceiling or roof. If such parts are not provided by the supplier, you will need to make them yourself.

Preliminary calculation of the chimney system

When planning the installation of a stainless chimney, it is necessary to take into account several important criteria, which are provided for by special fundamental documents of the technical supervision service:

1. The total height of the chimney cannot be less than 5 m - to ensure normal draft.

2. The construction of horizontal sections more than 1000 mm in length is not allowed.

3. In unheated rooms or in open space (on the street), the installation of elements that do not have their own thermal insulation is prohibited.

4. Particular attention to the excess of the chimney cut above the roof:

  • If the roof is flat - at least 500 mm.
  • The same requirements apply if the distance from the pipe to the ridge of the pitched roof is less than 150 cm.
  • At a distance of 150 to 300 cm, the pipe must be at least level with the height of the ridge.
  • At large distances, the pipe cut should not be below a line of 10º from the ridge height horizon.
  • There are situations when other buildings are attached to the main building. In this case, the height of the pipes must be at least higher than their upper level.

5. If the chimney passes through a roof made of flammable materials, a spark arrester must be installed.

6. The most critical areas are passage through walls, ceilings, and roofs, especially if they are made of flammable materials. If the pipe is uninsulated (single-walled), then the distance between it and the ceiling must be at least 1000 mm. This, in fact, is not practiced, but even with a sandwich thickness of 50 mm, the minimum gap should be 200 mm.

7. Pipe joints in thick walls or ceilings are not allowed. Minimum distance from floor, ceiling, wall – 700 mm

8. When a chimney passes even through a non-combustible roof, the minimum gap between the pipe and the covering cannot be less than 130 mm.

9. Two basic rules must be taken into account:

  • On a horizontal or inclined section from a heating device or stove, pipes are installed “along the smoke”, i.e. so that combustion products move freely along the internal channel. In practice, this is a pipe that is put on the previous one from the boiler.
  • On the vertical section of the chimney, the opposite is true - installation is carried out “through condensation”, so that the resulting moisture “has no chance” of getting into the insulation. Thus, each subsequent pipe section is inserted into the underlying one.

10. The diameter of the pipe at any of its connections cannot be smaller than the standard outlet pipe of the heating device.

11. The total number of chimney turns, regardless of their angle, is no more than three.

The chimney may have an internal layout, passing through the premises of the house. In this case, either thermally insulated sandwich pipes, or the chimney itself can be covered with brickwork.

Recently, with the widespread use of double-layer insulated parts, its external placement, with brackets attached to an external wall, has become a more popular scheme.

The location of the chimney outside on brackets...

or with the installation of a special supporting structure made of a metal profile.

...or on a special supporting structure.

The advantages of such placement are obvious - there is no need to arrange complex thermally insulated passages through interfloor ceilings and roofing.

Installation of a stainless steel chimney

Actually, if the chimney scheme is carefully thought out, the approval of the regulatory authorities is obtained ( this is a prerequisite), all the necessary parts for the future system have been purchased, then installation is not particularly difficult. All elements are equipped with adapted mating areas, and connecting them one to another is a simple and intuitive task.

It is advisable to further strengthen pipe joints, especially inside living spaces, with a special sealant that can withstand temperatures up to 1000-1500º - it is easy to find in specialized stores that sell components for chimneys. This will ensure that combustion products hazardous to health are avoided from entering the premises and reducing draft in the system.

When mounting the chimney on an external wall with brackets, the distance between them should be no more than 2 m. A bracket (support) is required where the pipe passes through the wall and where the condensate collector (inspection compartment) is attached.

If installation is carried out indoors, then the main attention is paid to the places of passage through the ceilings. Some manufacturers of chimney systems include special elements for these purposes in their range. But, if there are none, it’s easy to make them yourself.

Essentially, this is a box with a central hole for the passage of a pipe of the appropriate diameter, and a length of walls that provides the required distance of the chimney from the floor material. Very often it is also made from stainless steel.

It is mounted in the thickness of the ceiling, the free space in it is filled with non-combustible material (basalt wool or expanded clay). It can be covered with a decorative plate at the top and bottom.

On the roof there is a slightly different approach.

  • Firstly, if it has a certain angle with the horizon, the hole for the pipe will not have a round shape, but an elliptical or rectangular elongated shape.

    • Installation of a passage through the roof

    • Thirdly, in addition to thermal insulation, it is necessary to provide waterproofing on top - so that precipitation or condensed moisture does not penetrate into the attic. Today it is easy to purchase special flexible elements that will fit any roof profile.
    • It would be useful to put a “skirt” on the chimney pipe, which will protect the joint with the roof from direct rain.

    “Skirt” to protect the passage through the roof from direct rain jets

    The pipe is topped with a head - an umbrella. In a number of cases, which have already been mentioned, the installation of a special element - a spark arrester - will be required.

    Video. Master class on installing a stainless chimney

    In fact, if the installation scheme is thought out to the smallest detail and agreed upon with regulatory organizations, then the installation itself turns into an easy “game of children’s construction sets.” Of course, you shouldn’t take everything so simply - the appropriate skills in reading drawings, plumbing, the ability to use power tools, accuracy, and consistency in work will be required to the fullest.

Nowadays, instead of laying the usual brick chimney, they are increasingly resorting to installing stainless steel chimneys to remove combustion products. The popularity of such modular prefabricated structures is explained by ease of assembly, long service life and high reliability. If you wish, you can assemble the chimney yourself, but to do this you need to understand the design features and comply with the basic technological requirements. Let's consider each of the listed points in more detail.

Purpose and parameters of stainless chimneys

Metal chimneys produced today are made of stainless steel, various alloys and materials and may differ in shape. Usually these are straight or telescopic structures made of stainless steel sandwich pipes or corrugated flexible chimneys. One of the important points in the installation process is the build quality. As a result, draft improves, fuel burns completely, and boiler performance increases. Fewer harmful substances are released into the atmosphere in the form of smoke and soot, volatile acid compounds and resins. And gaseous combustion products, carbon monoxide, ammonia and other compounds are completely removed to the outside.

Also, the installation of the chimney must be carried out in compliance with safety regulations and basic legal standards. According to these requirements, the cross-section of the chimney must correspond to the power of the boiler, and its height must exceed 5 m. Moreover, to avoid turbulence and backdraft, the upper element must be located above the roof. On the chimney itself, the number of turns and broken segments should be minimal. For ease of cleaning and maintenance of the chimney, it is important to provide free access, and for condensate removal - a separate drain pipe.

Manufacturers of prefabricated chimney structures take these requirements into account, therefore all manufactured products have:

  • rounded shape with a smooth surface, which promotes stable traction;
  • minimal condensation formation;
  • high characteristics of heat resistance, tightness of connections;
  • high fire resistance and safety;
  • easy assembly and maintenance.

When buying modular chimneys made of stainless steel, be sure to select them in accordance with the power of your boiler or stove.

Flexible chimneys greatly facilitate the installation of the heating system, especially if it is not possible to lay the smoke exhaust system in a straight line. The corrugation perfectly withstands high temperatures, resists temperature changes well, and its rapid heating ensures stable traction.

In the manufacture of pipes and other elements, steel with low chromium content and galvanized sheet iron are used. Therefore, sandwich pipes have excellent anti-corrosion characteristics and perfectly resist the aggressive effects of acidic compounds derived from the combustion process.

Several types of steel grades are used:

  • 304 is the best solution for less aggressive environments;
  • 310 – the most heat-resistant, durable, strong, therefore suitable for powerful heating equipment;
  • 316 – resists acidic compounds well;
  • 321 – have increased heat resistance, up to 850°;
  • 409 – for fireplaces, stoves, solid fuel boilers;
  • 430 – for low-aggressive environments.

When producing multilayer sandwich pipes, their inner side is usually made of high-performance heat-resistant steel. Steel on the outside has more modest performance.

When assembling the smoke exhaust system, the following elements will be required:

  1. 1. Sandwich pipe. This is the main element of any chimney. The connection of the pipe, like other elements, is carried out as a socket. For greater reliability, clamps can be installed at the connection points.
  2. 2. Bend at an angle of 45°. Used to connect two pipes and change the slope of the chimney at the junction of horizontal and vertical fragments.
  3. 3. Universal bend at an angle of 90°. Another rotating element used to change the configuration of the chimney.
  4. 4. Tees. Serve to remove flue gases and cut off condensate.
  5. 5. Condensate drainage. Installed below on the vertical part of the chimney.
  6. 6. Revision. Usually installed under a tee. The presence of a hatch allows you to use it to clean the chimney from soot.

Instructions for internal installation - all work from A to Z

Do-it-yourself assembly of modular chimneys has become widespread today. This is facilitated by ease of installation, fastening and sealing, a wide selection of parts and components, as well as the ability to choose the optimal configuration for any case and ensuring good draft while maintaining high boiler efficiency. We begin installation with preliminary calculations, selection of the expected chimney configuration and wall markings. At this stage, we choose the chimney installation scheme - internal or external.

First, let's consider a variant of the internal installation diagram. In this case, we lay the pipes through the ceilings and roof. You should know that a chimney located inside a building is less susceptible to external influences, and the formation of condensation is minimal. Since we carry pipes through floors and roofs, the installation work is quite labor-intensive and technologically complex. At the same time, part of the internal space of the premises is occupied. Next, we calculate the length of the structure and select the necessary rotary and operational elements.

We must add 25-50 cm to the total length of the structure to extend the pipe above the level of the roof ridge, which is necessary to ensure good traction! Assembly begins from the heating device - a boiler or stove, onto the pipe of which we put an adapter. Be sure to coat the transition area with heat-resistant sealant and clamp it with a metal clamp. Then we continue to assemble the pipes and all the elements until we bring the chimney above the roof ridge.

First, we install a thin-walled pipe of the same cross-section as the sandwich pipes, but without insulation, since under the influence of high temperatures the thermal insulation sinteres and loses its initial characteristics. At the vertical outlet, it is possible to install a tank for heating water and a heater grid.

When passing through the ceiling, be sure to attach a passage unit filled with thermal insulation material. The knot is easy to make yourself, but it’s easier to use a ready-made structure. Having installed and secured the unit motionless, we thread the sandwich pipe through it. The unit can be fixed to the ceiling using metal profiles or on the back side of the roof with a metal sheet with an elliptical hole.

Joining pipes in the ceiling or at the roof level is unacceptable. The joint should be 250–300 mm above or below the level.

On top of the roof we put a conical roof on the pipe - a special element with an angle equal to the steepness of the roof slope. We place the upper edge of the canopy support plate under the roof and secure it to the roofing decking. If it is not possible to get the edge of the roof plate, then seal the connection with sealant. Finally, we cover it with comfrey, install the cone and the required head. This completes the installation work.

External installation of a stainless steel chimney - how to proceed?

Now let's look at how to properly assemble an external chimney (the pipes are installed on the outer wall of the building). To bring the pipes through the wall, we make only one passage. We fasten the elements to the wall, when going around the ceiling and roof, using brackets and support platforms. The advantage of this solution is that the pipes do not occupy internal space, and the risks of accidental fire and carbon monoxide poisoning are minimized. But they spoil the appearance of the building and are more exposed to the external environment.

Assembling a sandwich chimney starts from the heating device. Therefore, we put an adapter on the boiler (stove) pipe. To reliably seal the walls of the pipe and the pipe, we coat it with heat-resistant sealant and clamp it with a metal clamp. We install a horizontal section, its length should not exceed 1 meter. Why do we punch through the wall a hole with a larger diameter than the size of the pipe, or a square opening measuring 400x400 mm. Leaving a small gap for laying thermal insulation, we insert the passage block.

The gap for thermal insulation for walls made of combustible materials is maintained at least 200 millimeters! In walls made of fireproof materials, we can install a section of asbestos-cement pipe, fixing the sandwich element with mineral wool, tightly hammering it in on all sides. We cover the outside of the passage unit with a metal plate. If there are small gaps left, fill them with sealant.

On the wall, below the exit of the sandwich element, we attach support brackets with a plate. We install inspection and condensate removal blocks on the plate and begin to assemble the vertical part of the chimney. We fix each of the links with clamps, and fasten the finished pipe with brackets to the wall in increments of 1.5–2 meters. Additional fastening with brackets is necessary at the junctions of bends and tees, if the structure is heavy! At the end of the installation work, we install the cone and the required head. If necessary, we secure the top of the pipe, which will protect the chimney during strong gusts of wind. We install a chimney as protection against precipitation.

As you can see, installing sandwich pipes is not difficult. But in the process of work it is necessary to be careful, careful, especially when working at height, and to take into account all the little things. After all, the slightest miscalculation can lead to a fire hazard or other troubles.

Hello, dear guest!

Do you know what a sandwich and a steel pipe have in common? No? Then make yourself comfortable, it will be interesting.

The first sandwich appeared back in 1762. True, at that time this term meant exclusively a closed burger, named after the English count.

In the 21st century, the sandwich has moved from the kitchen to the construction industry and now represents a convenient and practical multi-layer engineering solution. I propose to pay special attention to it, and from today’s article find out why it is needed and why it is better than conventional, “inedible” systems.

Any chimney performs two main functions - removing combustion products and providing normal draft necessary for a good flame.

A sandwich is a structure made of two pipes inserted into one another, with insulation laid between them. In our case, both pipes are made of stainless steel, and the insulation is either perlite sand.

How the chimney works

The chimney structure can be schematically represented as follows:

  1. Inner pipe. The weld is made using TIG technology in a special gas environment.
  2. External stainless steel contour.
  3. Thermal insulating non-flammable material. The most popular is stone (basalt) wool with a density of approximately 200 kg/m3. Thickness – from 25 to 100mm;
  4. Interface system - narrowed sections and sockets designed for a tight connection;
  5. Reinforcing clamps.

All sizes must be calculated, as I will tell you in one of the following paragraphs.

Principle of operation

Combustion products are saturated with aggressive chemicals that activate corrosion processes. Under the influence of the temperature difference between the outgoing gas and the outside air, condensation forms, “corroding” the walls of the smoke channels. In addition, rapid cooling of the gas helps reduce thrust. Therefore, the outer sections of the chimney must be insulated in various ways.

Sandwich pipe is a ready-made engineering solution that minimizes temperature differences.

In addition, the single chimney “at the outlet” of the furnace becomes very hot and poses a certain threat to humans. By installing a “sandwich” chimney, this problem can be avoided. In addition, it has a smooth surface, making it very difficult for condensation to linger on the walls of the chimney.

Types and designs

The double pipe is made from the following types of stainless steel:

  • AISI430 is the cheapest and low-alloy steel option. The material does not weld well and burns out faster than other types of metal;
  • AISI439 – contains titanium, which in itself increases the material’s resistance to high temperatures and corrosion;
  • AISI316 – alloyed with nickel and molybdenum, characterized by good heat resistance and acid resistance;
  • AISI304 is similar to AISI316, but a little cheaper;
  • AISI 321 is an imported analogue of domestic stainless steel 12×18n10t, the optimal grade for chimneys.

Factory products usually have a length of 0.5 to 1 m. The most common diameters of internal pipes are 110mm, 115mm, 120mm, 150mm, 200mm and 300mm. External diameter – from 200 to 430 mm. Wall thickness -0.5 and 1 mm.

Chimney design:

  • Stainless steel “Sandwich” pipe 0.5, 1 m long) removes combustion products;
  • 45 degree elbow – helps change the direction of the chimney;
  • Tee - removes condensate and gas;
  • Inspection - a window designed for cleaning the chimney;
  • Adapter - used to connect elements;
  • Kagla - regulates traction;
  • Weather vane - shows the direction of the wind;
  • Cone - protects from precipitation;
  • Deflector – protects from dirt and dust, maintains traction;
  • Conical roof - a chimney element that serves for the correct transition of the chimney through the roof;
  • Crimping clamps, wall connecting parts;
  • Fungus is a decorative element;
  • The glass is a part for passing through the roof.

Advantages and disadvantages

I propose to figure out why the double-circuit air duct has become so popular and analyze all its pros and cons.

Advantages of the system:

  • Small amount of condensate;
  • Operational safety (with proper installation);
  • High fire safety (withstands up to 850 degrees) due to the heat-insulating layer;
  • High quality materials;
  • Easy installation;
  • Small everything, compared to ceramics and bricks;
  • Ideal smoothness of the internal surface, which does not require additional internal finishing;
  • Resistance to temperature influences and aggressive environments;
  • Attractive design

Flaws:

  • High price;
  • Relatively short service life.

The service life of such a chimney

Service life is one of the disadvantages of a stainless steel sandwich chimney. It largely depends on the material from which the system is made, the thickness of the walls and the quality of the weld. The shortest service life with the same thickness is for AISI409 stainless steel, the longest is for AISI321.

Most manufacturers claim a service life of 10-15 years, but in practice it is much less.

Make it yourself or order it

An important question for a builder is: what is better, making a chimney yourself, or using the services of a specialist?

Do not forget that an improperly designed chimney system can contribute to a fire and the accumulation of deadly carbon monoxide. Therefore, it is always necessary to seek advice from a competent specialist.


But if you want to save money, or there is no suitable specialist in your area, you will have to master the installation of a chimney yourself. To do this, first familiarize yourself with all the requirements of SNiP, make an accurate calculation and watch a couple of dozen videos on the topic.

The advantage of self-assembly is saving on the cost of materials (at least 2 times) and on labor. In addition, you can independently choose the materials for the sandwich pipe and be confident in its long “life”. Disadvantages - calculations using factory products are much simpler and more accurate.

Building regulations

Fire safety requirements for chimneys

The main documents regulating fire safety are SNiP 41-01-2003, P 7.13130.2013 and VDPO.

Required excerpts:

  • The distance from the “sandwich” pipes to rafters, sheathing, and other roofing and ceiling parts made of flammable materials should be at least 130 mm;
  • In this case, the temperature of the exhaust gases should not exceed 500 °C for stainless steel pipes. The use of stainless steel chimneys for coal-fired stoves is not permitted. It is allowed to provide pipe bends at an angle of up to 30° to the vertical with a distance of no more than 1 m;
  • Setback - the space between the external chimney and a wall, partition or other building structure made of flammable materials should be taken equal to 500 mm and 380 mm - from non-combustible materials;
  • The elevation of chimneys above the roof should be up to 500 mm if the roof is flat; up to 500 mm above the roof, if the pipes are located less than 1.5 m to the parapet or ridge; not less than the ridge axis, if it is located 1.5 - 3 meters from the ridge.
  • The wall thickness of metal pipes is not allowed below 0.5 mm;
  • The diameter of the chimney must be no less than the outlet of the stove or boiler pipe;
  • It is prohibited to use flammable insulation for sandwich pipes;
  • Be sure to organize audits for cleaning.
  • Chimney mouths should be protected from precipitation. Umbrellas, deflectors and other attachments on chimneys should not interfere with the free exit of smoke.

Traction force

  • It is necessary to completely and freely exhaust exhaust gases into the atmosphere; draft is ensured by the correctly selected height and cross-section of the pipe (clause 5.1.1.VDPO);
  • You should periodically check for normal draft and clean chimneys at least once a year;
  • The minimum permissible chimney length is 5m. If the chimney is shorter, a special pump is used to pump out the smoke;
  • In the channel, the flow air speed should be in the range of 15 - 20 meters per second.

Important! Some craftsmen believe that the sandwich design itself allows the distance from the pipe to the combustible elements of the ceiling to be reduced to 380 mm, but personally I would not risk it.

Making and installing a chimney with your own hands

Step-by-step instruction:

  1. After familiarizing yourself with all the requirements of building codes and regulations, you need to draw up a diagram of the future chimney. Figures 1,2,3 show approximate options.

Drawing and diagrams:




  1. Size calculation

When calculating the diameter of the chimney pipe, the following rules are used:

  • For stoves with open fireboxes, fireplaces, or gas boilers with an open combustion chamber, the diameter of the chimney pipe must be at least 1/100 of the volume of the combustion chamber;
  • The chimney diameter for gas equipment is always indicated by the manufacturer in the passport.
  • In closed-type furnaces, the cross-sectional area of ​​the inner pipe must exceed the cross-sectional area of ​​the inlet.
  • The resulting diameter of the internal section is rounded up;
  • If the diameter is exceeded by more than 1.5 times from the calculated one, turbulence will appear inside the chimney, worsening draft.
  • If a square or rectangular chimney is used, the cross-sectional area of ​​the internal cross-section of the pipe is taken to be 1.2-1.4 times larger than that calculated for a round chimney.
  • The height of the chimney is calculated according to SNiP. The height of the chimney to the roof can be measured or found out from the house plan.

The thickness of the insulation in a sandwich chimney can vary from 25 to 60 mm.

In accordance with the requirements of the Building Codes and Rules, to select the correct chimney, you need to take into account the thermal power of the heating boiler:

  • When the power of the heating unit is no more than 3.5 kW, it is optimal to use a pipe with a cross-section of 0.08-0.14 meters.
  • From 3.5 to 5.2 kW - pipes with a cross-section of 0.14 - 0.2 meters;
  • At power levels from 5.2 to 7.0 kW, it is recommended to use pipes with a cross-section of 0.14 - 0.27 meters.

The calculated dimensions of factory-made sandwich pipes are presented in Table 1.


  1. installation video

You should check out several installation videos

Let me give you an example:

Installation features

It should be so that the wide part of the inner pipe is directed upward. Professionals call this method “condensate”.

Smoke in this design rises upward, and condensate flows down. The outer pipe is positioned with the wide end downwards (“along the smoke”).


Chimneys are divided into external and internal. Advantages of an attached chimney:

  • Ease of maintenance,
  • Location outside residential premises;
  • There is no need to arrange junctions through the floors.

If you decide to install a chimney inside the house, there are also certain advantages. It will be less exposed to weather conditions and will therefore last longer.

Important! Between the heating unit and the sandwich chimney there must be a piece of pipe without insulation. Ideally, equip it with a protective mesh made of bricks.

The chimney should be installed from the bottom up, in the direction of the smoke. When connecting, be sure to use a heat-resistant sealant.

The minimum distance from the smoke exhaust system body to ceilings and floor structures is listed in SNIP (see above). It is impossible to violate the requirements, as this may result in a fire in the structure.

Sloping sections must be smooth, with a cross-section no less than the cross-section of the vertical smoke channel.

Frequent errors and problems during installation

  • Use of non-heat-resistant sealant;
  • The depth of the pipe in the fastening area should not be more than 0.5 of the outer diameter of the structure;
  • Under no circumstances should any chimney elements come into contact with gas pipes or the electrical wiring system;
  • Clamps should be installed under maximum mechanical stress;
  • Inconsistency of the dimensions of the chimney passage through the ceilings with the requirements of SNiP;
  • Some craftsmen ignore the need to install a gate (alas, you will have to disassemble the entire pipe);

Maintenance and cleaning

Sandwich chimney cleaning is divided into 3 types:

  1. Mechanical. Using a special brush or brush made of plastic. The diameter of the product for cleaning is selected 20% larger than the diameter of the smoke channel;
  2. Chemical. A special solution is applied to the inner surface of the chimney to dilute carbon deposits, soot and soot;
  3. Smoke. The stove or boiler is heated with potato sedums or dry aspen logs. Steam from such raw materials removes soot. Such cleaning is suitable as a preventive measure when the layer of soot inside the channel is not large.

How to insulate?

The double-circuit structure of the sandwich chimney is already insulated, so additional measures for its insulation are not required.

Welcome!

The chimney is a pipe structure of a predominantly vertical type. It is designed to remove combustion products generated during the operation of heating and other appliances (boilers, stoves, fireplaces) into the atmosphere.

How does a steel chimney work?

Structurally, a steel chimney is a smoke exhaust duct made of a solid or segmented metal pipe, which is mounted on the chimney pipe of a heat-generating unit and flows out through a wall or roof, discharging exhaust gases to the street.

Depending on the specifics of the room and the location of the heating device, the configuration of the smoke exhaust circuit can be varied.

Principle of operation

The principle of operation of the chimney is based on the natural draft force that occurs in the circuit due to temperature differences. The heated air becomes light and naturally rushes upward.


Fresh cool air coming from outside not only replaces exhaust gases, but also supports the operation of the system as a whole, because oxygenated air masses support the physics of combustion.

Types and designs of stainless steel chimneys

Depending on the number of circuits, chimney channels are divided into:

  • single-circuit (single-walled).

The steel thickness of a single-circuit chimney varies in the range from 0.6 to 2 mm, while the choice of the required thickness is determined by the type of heat generator (more precisely, the type of fuel on which it operates). The most affordable option for self-assembly, however, the use of single-wall chimneys is possible only when the smoke exhaust circuit is located inside the house.

Insulation will most likely still have to be carried out, and independently, this will ensure the safe operation of the chimney, minimize energy losses and prevent the formation of condensation inside the circuit, and therefore extend the service life of the entire structure.

  • double-circuit (combined sandwich systems).

Chimney sandwich pipes consist of a pair of pipes of different sections inserted into one another. The insulation function is performed by non-combustible materials: vermiculite, basalt mineral (stone) or ceramic wool. Factory-made thermal insulation significantly facilitates the assembly of the structure, because there is no need to construct an additional protective casing, and it also evenly protects the circuit from the effects of sub-zero temperatures when removing the chimney from the room.

Double-walled chimneys are considered the best because... reliable and able to function equally effectively both inside and outside the house.


According to the type of design, chimneys are:

  • flexible (corrugated).

Corrugated pipes are ideal for arranging curved passages, perfectly adapting to any bend. This allows the use of corrugated stainless steel chimneys in houses with beam and sloping floors. The inner surface of corrugated chimneys is characterized by a minimum roughness coefficient, which prevents the deposition of soot and soot.


Spiral flexible walls significantly simplify the assembly of the structure and reduce its cost, because allow you to do without special rotating elements.

  • rigid (modular).

Rigid chimney pipes provide excellent stability of the chimney with minimal use of additional mounting brackets. The variety (turns, tees, etc.) allows you to set the contour in the desired direction. Assembly is carried out according to the type of constructor, when one element is attached to another.

However, adjusting the smoke exhaust line to the specifics of the room in terms of selecting the required length of a particular part can cause some difficulties.

According to the cross-sectional shape, stainless steel chimney pipes are produced:

  • round,
  • oval,
  • rectangular, etc.

Depending on the type of design solution, stainless steel chimneys are divided into:

  • internal, installed inside the house, and external, installed on the outside of the building. When placing a main in a house, chimneys additionally serve as a radiator.
  • straight and curved.


In addition, chimney pipes differ in overall dimensions: internal and external diameter, steel thickness, weight.

Advantages and disadvantages

Stainless steel chimney ducts are characterized by a number of advantages:

  • adaptability to any heating concept;
  • strength of steel body;
  • light weight and, as a result, no need to build a separate foundation;
  • long service period (up to 30 years);
  • high heat resistance coefficient. They are able to withstand temperatures up to 900⁰C;
  • resistance to destruction and vibration;
  • resistance to temperature changes, moisture and acid condensate formed inside the circuit;
  • immunity to corrosion;
  • operational safety;
  • ease of installation and minimal time spent on installation work;
  • the ability to give the smoke circuit the desired configuration;
  • ease of maintenance and repair work;
  • acceptable price.

Among the disadvantages it should be noted:

  • the need for thermal insulation measures (relevant only for single-wall chimneys);
  • visually unsightly design and, as an option, additional finishing in the form of erecting a decorative box. Although the natural specularity of stainless steel can easily be used in the design of any room.
  • non-solidity of the structure when using poor-quality or unsuitable sealant leads to depressurization of the circuit under the influence of high temperatures.

Service life of a stainless steel chimney

Of course, the “lifetime” of a stainless steel chimney is significantly less than its brick or ceramic counterpart. However, with proper installation and timely preventative maintenance, stainless steel chimneys can last about 30 years.

The warranty period from manufacturers is usually 15 – 20 years.

Make it yourself or order it

Stainless steel chimney pipes, of course, can be made with your own hands, but without special skills you should not take on this undertaking and thereby risk the health and lives of your family members. But it is quite possible to install a smoke exhaust duct yourself, without resorting to the help of experts.

When choosing a suitable chimney, you need to start from the power of the heat generator and the type of fuel it runs on. Actually, these indicators determine the diameter and wall thickness of the pipe.

  • Give preference to durable and first-class steel that can withstand heating to temperatures of at least 700⁰C.
  • Check the quality of the seam connection, which ensures the tightness of the chimney duct body. For a solid fuel boiler, laser welding is preferable; rolled seams are suitable exclusively for gas equipment.
  • Pay close attention to the characteristics of the insulating material. It must be made of fire-resistant raw materials, so glass wool is not definitely suitable. The quality of compression of the insulation will determine its service life.

Building regulations

All aspects of chimney installation are regulated by the following building regulations:

  • SNiP II 35/2.04.05-91/2.01.01-82;
  • NPB 252-98;
  • DBN V.2.5-20-2001;
  • GOST 9817-95.

Fire safety requirements for chimneys

Failure to comply with fire safety requirements can cause fires.

  • All ceilings through which the chimney pipe passes must be carefully insulated with fireproof materials.
  • The thickness of the insulating layer varies depending on the type of chimney in the range from 13 to 25 cm.

Traction force

The traction force determines the productivity of the equipment and the safety of the smoke exhaust circuit. It depends on a number of factors:

  • chimney pipe length;
  • contour angle;
  • the number of its bends;
  • presence of vertical sections, etc.

Do-it-yourself chimney installation

Before installation begins, a detailed diagram of the future chimney is developed, which must be approved by the regulatory authorities.

Upon completion of installation and inspection of the chimney circuit, a certificate of delivery and commissioning of the structure is drawn up and certified.

Required materials and tools

When working with modular smoke ducts, no special equipment is needed. All you need is sealant, metal clamps and insulation (if preference was given to single-wall chimneys).

In addition to the pipes themselves, you will need adapters and other components:


Drawing and diagrams

Before starting work, it is necessary to work out in detail the diagram of the future smoke exhaust line, which will outline the general configuration of the circuit and its central elements.


Size calculation

The technical data sheet of the heat generator traditionally indicates the required diameter of the chimney pipe. If you do not have this data, you will have to make the calculation yourself.

The simplest way is to take data from the table, based on the thermal power of the unit.


A more intricate, but most accurate calculation scheme for fuel consumption involves carrying out calculations in several stages:

  1. Determination of the volume of combustion products (Vg).


The values ​​of the specific volume (Vу) and outlet gas temperature (T) are obtained from the table:


  1. The cross-sectional area is then calculated:


  1. Using the formula for the area of ​​a circle, we calculate the diameter of the pipe (d):

The type of fuel used determines the thickness of the steel:

  • solid fuel (coal, peat, wood) – over 1 mm;
  • liquid fuel – from 0.8 mm;
  • gas – from 0.5 mm.

Installation video

Step-by-step video instructions will reflect the fundamental nuances of assembling chimneys:

Installation specifics

Installation of the chimney duct begins from the bottom. The assembly procedure requires starting work by installing the first part on the heat generator pipe; the diameters of both parts must completely coincide.


  • minimum bends and horizontal sections;
  • absence of intersections with electrical wiring and gas pipelines;
  • the places where parts are connected should not be on floors and walls;
  • The total height of the chimney must be at least 5 meters.

The seams are carefully sealed with heat-resistant sealant and, if necessary, additionally tightened with metal clamps.

To add structural rigidity, the chimney circuit is additionally fixed to the wall using brackets every 1.5 - 2 meters.

The circuit is routed through the wall using a special sleeve, which provides thermal insulation for the wall.


Similar actions are performed when laying a chimney line through the ceilings of a house:


Below are 2 options for passing a chimney through the roof:


On top of the roof, the passage of the pipe is additionally sealed with a special heat-resistant unit that prevents moisture from seeping inside:


The chimney is equipped with:

  • umbrella, spark arrester, deflector and weather vane. In modern models, these functions are usually combined;
  • snow cutter;


  • If the pipe height is large, it is necessary to install tension cables.


Frequent errors and problems during installation

  • Incorrect configuration. Unjustified deviation from verticality, sharp bends and excessive horizontal lines reduce the traction force in the circuit.
  • Insufficient or excessive shaft height also reduces the efficiency of the chimney.
  • If the pipe head enters the wind pressure zone, it provokes a backdraft effect.


  • The use of stainless steel of insufficient strength leads to its rapid wear and threatens to burn out the steel.

Maintenance and cleaning

Proper operation of the chimney during the heating season is based on systematic maintenance of the structure, which must be cleaned of soot, soot and debris at least 2 times a year.

  • burn household waste in stoves and fireplaces;
  • use resin-rich coniferous wood for kindling.

Today we will consider the advice of professional stove makers on the issue of sealing and insulating stainless steel chimneys.

Sealing and insulation

  1. Prefer only for chimneys (not to be confused with heat-resistant). The maximum temperature resistance indicator is indicated on the packaging.
  2. The internal seams of prefabricated modules, previously carefully adjusted to each other, are treated with sealant.
  3. Sealing work cannot be carried out at ambient temperatures below 5⁰C.


Thermal insulation of the chimney circuit is carried out with the aim of shifting the dew point (the place where harmful and toxic condensation forms) closer to the outlet, which reduces the volume of condensate in the system.


As insulation, you need to use a special fire-resistant material, characterized by:

  • plasticity, allowing it to be easily wrapped around a pipe and secured with clamps, wire, etc.;
  • lightness so as not to exceed the permissible load-bearing load coefficient on the system;
  • moisture resistance if used outdoors.


Conclusion

Stainless steel chimneys cope well with the loads placed on them. The ease of installation and maintainability made them a favorite material for stove makers. And their versatility and manufacturability allow them to be used even when restoring old brick chimneys.