Installation of a stainless steel chimney - how to work with sandwich pipes? Correct installation of a sandwich chimney with your own hands - assembly diagram How to properly assemble a chimney using condensate

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.

The main task when installing heating devices operating on the principle of combustion of solid or liquid fuel is the arrangement of the chimney. It is the hood that ensures the combustion process itself, saturating the combustible mixture with oxygen and creating draft, and also does not allow life-threatening products released during fuel combustion to accumulate in the room.

There are several ways to build a chimney with your own hands. We will consider the most modern of them, namely the installation of a chimney from sandwich pipes through a wall, in this article.

Contents of the article

What is a sandwich pipe?

A sandwich pipe is a construction kit made from different elements that allows you to assemble and install a chimney of any complexity and design with your own hands without any extra effort. Each such element has expansions and contractions on different sides, which allows you to assemble a reliable sealed structure, inserting one element into another.

The finished product is a double metal structure made of stainless steel with insulation inside. This feature allows you not to waste time, effort and money on solving additional hydro and water issues.

Chimney elements made from sandwich pipes

A chimney made from sandwich pipes, like any other chimney, has a rather complex design. When installing it through a wall or roof, you need to take into account the need for bends and turns, connection to the boiler, and the presence of a condensate cup. That is why manufacturers make various components for chimneys from sandwich tubes. To assemble a chimney without unnecessary problems, you only need to draw a plan and take all the necessary measurements of lengths, angles of bends and turns.

After this you will need to purchase:

1. Products of required sizes.
2. Tees designed for connection from the boiler to the condensate sump and the main chimney.
3. The elbows help to bend the chimney. They are produced with bend angles of 15, 30, 45 and 90 degrees.
4. Glass for collecting condensate.
5. Elements with improved thermal and waterproofing for the passage of a roof, ceiling, or wall.
6. Inspection elements with doors for .
7. The mouth is the upper end of the chimney.
8. The support console is an element necessary for installing a chimney.
9. Wall bracket for attaching the chimney to the wall.
10. Heat-resistant sealant and control clamps are also required.

Advantages of chimneys made from sandwich pipes

The method of arranging chimneys using metal sandwich pipes appeared on the construction market quite recently, but immediately gained wide recognition and popularity among developers. This is due, first of all, to the reliability of the design and ease of installation.

The sandwich pipe protects the chimney channel from external temperature factors. Thanks to this feature, the following advantages of this design can be identified:

• this type of chimney is perfectly compatible with any boilers and stoves operating on liquid or solid fuel;
• made of , protected from absorption of various substances, corrosion and destruction;
• thanks to the perfectly smooth inner surface, soot does not settle on the walls of the chimney, which makes it much rarer than any other similar design;
• the formation and settling of condensate is minimized;
• by equalizing the internal temperature of the smoke channel, constant draft necessary for high-quality combustion is ensured;
• insulation protects the outer casing from heating. This design does not pose a danger to adjacent ceilings and residents of the house;
• a chimney made of sandwich pipes, without unnecessary complications and costs, can be mounted outside the house, passing through the wall, which avoids the passage of floors and roofs, as well as saving usable space indoors;
• When installing a chimney through a wall or roof, the slotted openings in the building can be made much smaller than when installing any other chimney. In addition, you can purchase and install special pass-through modules yourself;
• a chimney made from sandwich pipes looks aesthetically pleasing and attractive, which means it does not require additional decoration on the facade of the house;
• Thanks to the lightweight, perfectly fitted elements, the installation of such a chimney can be easily done with your own hands. And the presence of various fragments allows you to correctly make all the necessary bends and turns of the chimney.

The main and, perhaps, the only disadvantage of sandwich chimneys is their high cost. But having spent the money once, you will be confident in your safety and the quality of the constructed structure for many years.

Installing a chimney is a very serious task, so you need to approach its solution with maximum responsibility. Don’t forget, performing work on installing a hood “carelessly” can cost the lives of you and your family.

There are certain rules and nuances that you need to know in order to properly install a chimney with your own hands.

What do you need to know before getting started?

• no matter how your chimney goes through a wall or through a roof, its total height cannot be less than 5 meters;
• the length of the horizontal section for chimneys passing through the wall cannot exceed 1 meter. In addition, this section of the chimney must have a slope of 3 degrees to ensure condensate drains in the direction opposite to the heating device;
• the distance from the wall to the outer casing of the chimney must be at least 25 cm. As a rule, the manufacturer himself determines this distance by making a wall bracket with a base of the required length;
• the distance between the brackets on vertical sections should not exceed 2 meters, on horizontal sections - 1 meter. If the building design allows, it is better to install a bracket every 60 cm.
• Particular attention should be paid to the height of the chimney above the ridge. If the distance from the ridge to the chimney is less than 1.5 meters, the pipe should rise 0.5 meters above the ridge; the same height should be maintained in the case of a flat roof. If the distance from the ridge to the chimney is more than 1.5 meters, the height of the pipe rise should correspond to 10 degrees from the horizontal line of the ridge.
• If the roof of the house is made of flammable materials, the chimney must be raised at least 1.2 meters above it. Besides It is necessary to equip a special spark arrestor.
• if there are any extensions on the roof, the pipe must rise highest;
• if the height of the pipe above the roof exceeds 1 meter, it must be equipped and attached to the roof with additional braces;
• When drawing a chimney, try to draw it in such a way that you have to make a minimum number of turns and bends. The installation instructions allow you to do no more than three.

Features of installing a chimney from sandwich pipes (video)

Chimney installation

It is correct to start installing any chimney with your own hands from the heating device.

• first, an adapter is placed on the outlet pipe of the boiler or furnace on a heat-resistant sealant (withstands 1000 - 1500 degrees), and then clamped with a clamp;
• Next, a horizontal chimney element is installed. This section uses a single pipe with a damper to control draft. The first element does not use a sandwich, since high temperatures will quickly deteriorate the insulation and, as a result, will cease to perform its function;
• To pass through the wall, a hole is made in it. If the building is made of flammable material, the distance from the pipe to the edges of the building must be at least 20 cm. The opening is lined with fire-resistant basalt cardboard, then a passage block is inserted into it;
• A sandwich pipe is passed through the hole of the block, which is connected to the adapter of the heating device. The space of the passage block is filled with mineral vasalt wool. From the outside, the structure is closed with a homemade or factory plate. Sealant is used to fill the remaining holes;
• in the place where the pipe passes through the wall, support brackets are installed to which the plate is attached. It is necessary to assemble this structure to ensure the stability of the vertical pipe;
• then a tee with a tap for draining condensate and a hole for connecting a vertical pipe is attached to the horizontal element;

• To ensure the unhindered passage of smoke and gases, as well as to minimize the entry of condensate into the insulation, it is better to assemble the vertical part of the chimney as follows: the inside of the upper element of the sandwich pipe is driven inside the lower one, and sealant is applied to the joint. Then the outer part of the upper element is pushed onto the lower one, and then tightened with a clamp. This method allows you to assemble a chimney as quickly and efficiently as possible;
• we install the entire vertical part of the chimney pipe according to the same principle, including elbows for bends if necessary to bypass a window or other obstacles;
• each sandwich pipe link is attached to the wall using a bracket;
• We finish the installation by installing;
• if necessary, put on a special bracket, and then We secure the chimney pipe with guy wires.

It's not that difficult to set up. However, you should not forget about the rules, as well as the features of this work. Remember, there can be no trifles when it comes to flammable substances or carbon monoxide. Be careful.

There are two main connection devices in the chimney: “smoke” and “condensate”. How are they different and what assembly scheme should be used to avoid problems in the future?

Assembly "by smoke"

Assembly "by condensate"

How to install pipes and assemble a chimney

Condensation and its effects

Liquid appears when fuel is burned. It usually contains hydrocarbons, sulfur, oxygen and potassium substances. During the combustion process, when oxygen combines with hydrogen, water vapor is actively synthesized, which in itself is a corrosion agent. In addition, a lot of water is contained in the fuel itself. For example, anthracite gives 3% of smoke steam, firewood - 30%.

When is it correct to assemble a chimney “by condensate”, and when “by smoke”?

It is especially important to correctly assemble the “condensate” for:

• Chimneys of gas boilers. They have abundant formation of water precipitation due to the low temperature and high saturation of flue gases with steam.
• Stoves and fireplaces with a chimney installed outside the house. In such a chimney in winter, flue gases cool faster and more strongly compared to a chimney that goes inside the house. Therefore, more condensation forms.
• Any firebox with smoldering combustion.

Not a single boiler installation or furnace that burns any type of fuel can do without a chimney. At the moment, there is a large selection of different materials for the construction of chimneys. Of these, the most preferred are modular products supplied in sets, the so-called sandwiches. This material will cover issues related to the design of such pipes and their choice in each specific case. We will also look at how to properly install a sandwich chimney with your own hands.

Sandwich chimney device

Modular kits get their name because they consist of separate finished parts - modules of fixed sizes (usually 1 m long).

Each module is a sandwich pipe consisting of 3 layers:

• internal circuit for combustion products: made of heat-resistant stainless steel;
• insulation layer: usually basalt fiber with a density of up to 200 kg/m3, less often polyurethane foam;
• outer contour: serves as protection for the thermal insulation material. The circuit material is stainless or galvanized steel.

The design is cylindrical because it is considered optimal from an aerodynamic point of view. The layers are bonded together with a special adhesive; the thickness of the thermal insulation may vary depending on the specific operating conditions. The modules are connected to each other using the sewer pipe method, so one end is made in the form of a socket, and the second has a narrowing.

In addition to straight sections, sandwich chimneys are equipped with a tee for inserting into a vertical section, a unit for condensate drainage and fasteners. If necessary, the kit can be supplemented with the same insulated bends at an angle of 90 or 45 degrees in order to make turns of the channel, and even ready-made units for passing through the ceilings (cuts) and the roof (roofs). The advantages of three-layer systems over other chimneys are as follows:

• speed and ease of installation: the construction of any other pipe with insulation will take much more time;
• excellent performance and durability;
• the outside of the chimney sandwich pipes have a low temperature and are therefore fireproof;
• The products are distinguished by their aesthetic appearance.

Note. Many manufacturers offer sandwich kits with exterior powder coating in almost any color.

Before choosing three-layer pipes, a chimney installation diagram must be drawn. Ideally, such important parameters as the diameter and height of the chimney are calculated by specialists, but homeowners rarely turn to them for help, trying to save money and solve all the issues themselves. To make their task as easy as possible, we will give some recommendations in this regard.

The diameter of the chimney pipe can be selected according to the outlet pipe of the boiler installation. The rule is simple: the flow area of ​​the sandwich should not be less than that of this pipe. More is allowed. As for the height, you can get a guaranteed result if you take its value to be at least 6 m. Moreover, the height is measured from the grate of the solid fuel boiler to the upper cut of the pipe.

If the boiler is gas, diesel or pellet, then the height of the chimney must be measured from the burner device. In this case, it is necessary that the chimney, or rather its cut, does not fall into the zone of wind support, otherwise the natural draft will be very weak. To avoid this, the following scheme is used in calculations:

In order to reduce the resistance of smoke channels, it is not recommended to make a large number of turns, a maximum of 3. And then, we must strive to use bends everywhere at an angle of 45º, and not 90. The length of the horizontal section before the tie-in is no more than 1 m. Observing these recommendations, you need to draw an installation diagram and mark on it the places where the flue duct is attached to building structures.

When the diagram is ready, you can safely select sandwich chimneys. There are several caveats here related to the quality of the products and the presence of a large number of fakes on the market. Point one: high-quality stainless steel alloyed with chromium does not attract a magnet at all. This fact should always be checked by taking with you a magnet wrapped in matter. The latter is needed so that during inspection you do not scratch the shiny surface of the metal and do not create a reason for a conflict with the seller. If the magnet is even slightly attracted, then you have a low-quality product.

Pay attention to the thickness of the steel from which the chimney sandwich is made. For example, high-quality Russian-made products sold under the VULCAN brand are made from metal 0.5 mm thick. When you come across a thinner stainless steel, know that it will burn out just as quickly; when choosing, be guided by a thickness of at least 0.5 mm.

Well, one last thing. Carefully examine the tee where the horizontal section cuts into. For convenience, ask the seller to attach a condensate collection unit to it. Then the opposite end of the tee, where the sandwich pipe for the chimney is connected, should have a socket and not a narrowing. If this is not the case, you should refuse such a purchase.

Note. When connecting three-layer flue modules, the inner contour of the upper section fits into the socket of the lower section, and the outer, on the contrary, is put on the lower pipe. Therefore, the socket on the tee must be observed from above, in the internal contour. You will get more information about choosing sandwich chimneys by watching the video:

How to assemble a sandwich chimney

First, a little about the scheme according to which the installation of a chimney from sandwich pipes is correctly carried out. There are two of them: for smoke and for condensate, and the first one is incorrect. This is easy to figure out by looking at the picture:

On the left, the red arrow shows how, when assembled “through the smoke,” condensate flowing down the walls safely gets inside the sandwich through the gap if the connection is incorrect. The worst thing is that during operation you will not see these drips, like on a regular single-wall chimney. All condensate will go into the insulation, and then when it freezes it will gradually rupture the pipe, separating the upper circuit. That is why it is so important to pay attention to this fact when choosing pipes, as we said above.

The figure on the right shows the correct assembly of sandwich chimneys - “according to condensate”. The latter in this case successfully flows along the joint and rushes down into the condensate collector. The same thing happens outside, precipitation flows down the pipe without flowing inside and without soaking the insulation.

There are two types of pipes for removing combustion products: internal and attached. The first is connected to the boiler and goes outside inside the house, bypassing the floors and roofing.

Such chimneys are often used for baths. The second type differs in that the pipe from the boiler immediately goes outside and then rises to the required height. This method is preferable because:

• does not take up space inside the house;
• does not require additional passage units through the floors;
• much easier to install and cheaper;
• more convenient to maintain.

External chimney

In any case, the installation of a sandwich chimney starts from the boiler. First, a horizontal section is connected, whose length cannot exceed 1 m. During installation, a slight slope is maintained away from the boiler installation to the vertical channel. The goal is to prevent condensation from entering the heating unit.

The next step is to go through the outer wall. If it is made of fireproof material, then three-layer chimney pipes are passed through a sleeve made of asbestos or metal. The easiest way is to make a sleeve from a pipe of larger diameter, and the gap between it and the flue must be sealed with asbestos cord or basalt fiber. The insert into the tee is located outside, and a condensate drainage unit is connected to its lower branch pipe.

When making a passage through the wall, you need to make sure that there is no junction of two sections in this place.

If the wall is wooden, then you will need to provide a gap between it and the pipe of at least 200 mm. Usually, to do this, a square opening of the required size is cut out in the wall, into which a special metal passage unit is inserted, shown in the photo below. The gas duct is laid through it, and the gap is filled with basalt fiber.

The vertical channel is installed from the bottom up, using clamps and heat-resistant sealant to seal the joints. At the same time, the chimney is attached to building structures using steel brackets. The latter are placed in such a way that the fastening clamp does not fall on the junction of two sections of the pipe. A nozzle or umbrella is installed on the cut of the sandwich pipe.

Chimney inside the house

By and large, there is no particular difference in the sequence of work. There are only additional operations when it is necessary to install additional elements of the chimney in places where it intersects the ceiling and roof.

These places must be chosen so as to maintain the distance from the walls and at the same time not lay the pipe in the middle of the room. The passage of the ceiling is similar to the intersection of the outer wall described above, but the passage through the roof is more difficult to arrange.

It's good when the roof is flat. Then you can use a simple galvanized element, part of which should be placed under the coating to prevent water from flowing in. But most often the roof is covered with corrugated sheeting, metal tiles or slate. Then installing the pipe and sealing the passage is done using a special elastic element called a cap.

Conclusion

It should be noted that the process of assembling a modular sandwich kit is not very complicated. Installing a chimney with your own hands is entirely within the power of homeowners with their head and hands. It is important to calculate everything correctly, draw a diagram and prepare materials. The rest is just painstaking work that requires attention and patience.

FORUMHOUSE users are well aware that high-quality installation of a metal chimney directly affects the safety of living in a cottage. We have already written about that. It's time to talk about the features of installing a steel chimney.

1. What is a sandwich chimney

Despite the large selection of materials for installing smoke exhaust systems, reliable steel sandwich chimneys are most widely used in private housing construction.

A sandwich type chimney consists of two pipes of different diameters inserted into each other, and all the free space between them is a place to be filled with non-combustible insulation - mineral wool.

Mineral wool simultaneously plays the role of insulation and insulator.

Sandwich chimneys have the following main advantages:

• High installation speed and low cost compared to brick chimneys;
• Low weight of the smoke removal system;
• Smooth internal walls of the chimney provide good draft and help reduce soot formation;
• The use of acid-resistant stainless steel grades guarantees a long service life of the chimney.

The temperature of the flue gases directly depends on the type of heating boiler and the type of fuel used. The higher the temperature of the exhaust flue gases, the more the pipe and, accordingly, all the structural elements through which it passes, heat up. The following table will help you understand the dependence of the flue gas temperature on the type of boiler and the type of fuel used.

It should be remembered that unprotected wood begins to char at a temperature of 200 ° C. Well-dried wood can ignite from an open flame source at a temperature of 270-290 ° C. And if a wooden surface is subjected to constant heating for more than 24 hours in a row, then it can spontaneously ignite already at a temperature of 170° C. Therefore, when installing a sandwich chimney, it is important to observe all fire safety measures. And any mistake made at this stage can lead to dire consequences - fire and loss of property.

Urban:

– Two of my friends’ houses burned down due to an improperly installed sandwich chimney. Moreover, in both cases, the fire occurred in the place where the chimney exit was located through the wooden ceiling.

According to statistics, up to 80% of fires occur precisely because of improperly installed chimneys. Therefore, when choosing and installing a chimney, you must adhere to SNiP 41-01-2003 “Heating, ventilation and air conditioning”.

2. Chimney: distance to the floor slab and correct penetration

As practice shows, the greatest number of questions arise when calculating the distances from the chimney to wooden floors.

VadimPro:

– I built a house with a distance between the rafters of 60 cm. And only then I found out that according to existing standards, my chimney does not fit into this distance.

And again SNiPs come to our aid:

vova230:

– According to the standards, when driving through wooden floors, it is necessary to maintain a distance of 38 cm from the inner pipe of the sandwich to the combustible structures. All this space must be filled with fireproof material. If the standard passage does not provide this distance, then the dimensions of the furnace passage must be further increased.

If the chimney is laid through protected wooden structures, the distance can be reduced to 25 cm.

Protection of wooden structures - joists, ends of rafters, sheathing - is ensured by a galvanized sheet with an asbestos sheet of at least 5 mm thick laid between it and the wood.

Galvanization performs the following functions:

• Prevents the spread of fire in the ceiling;
• Provides uniform heat dissipation;
• Shields and reflects thermal radiation coming from the pipe.

In the case of tunneling between floors with a single-pipe steel chimney, the distance to unprotected wooden structures must be at least 50 cm!

Also, the parameters of the chimney should be calculated in such a way that the chimney pipe passes through the ceiling entirely - without joints with other elements. The chimney itself is installed through a passage pipe-cut, which is a metal box.

Specialist from the portal website Alexey Telegin from Moscow recommends:

– According to the standards, the thickness of the cutting (metal box) should exceed the thickness of the ceiling by 7 cm.

Sealing the floors where metal pipes pass from the stove with basalt fiber cardboard

Installation of polyurethane foam chimney

The process of installing grooves in a wooden floor can be divided into a number of successive steps:

1. Cut a hole in the ceiling with a size of at least 700x700 mm.

2. If necessary, remove or strengthen the floor beams.

3. We sew up the perimeter of the cut opening with fireproof materials, super insulation, etc.

4. For tightness, we place a sheet of basalt cardboard under the superisol.

5. We make a supporting frame from a galvanized profile, which is used when installing gypsum boards.

6. The dimensions of the frame are calculated for the PPU (ceiling-passage unit) fastening units.

7. We close the opening with sheets of mineralite or superisol with a hole for the passage of the inner part of the polyurethane foam.

8. We fix the foam.

9. Install the sandwich pipe.

10. We insulate the lower part of the polyurethane foam and the space around it with non-flammable insulation, this will avoid freezing and the formation of frost and condensation.

It is better to install and calculate the smoke removal system at the stage of designing the house!

It is also important to pay attention to how the pipes are connected to each other. There are two methods - “by smoke” and “by condensate”.

• Docking “through smoke” - the pipe of the lower bend of the sandwich goes inside the pipe of the upper bend of the sandwich. In this case, flue gases move freely up the walls of the pipe;
• Docking “by condensate” - the inner pipe of the sandwich: the upper one is inserted into the lower one, the outer pipe of the sandwich: the lower one is inserted into the upper one. With this installation, the pipe allows condensate to pass through, it flows down freely and does not flow out along the outside of the chimney, which can lead to a fire.

Kotlasky:

– The condensate pipe is usually installed on modern gas boilers, because they have a low temperature of the outgoing smoke.

For metal stoves and cast iron potbelly stoves, the smoke temperature is about 300°C; the steam that is released when burning wood begins to condense at a temperature of less than 100°C. At the moment of kindling, steam, falling on the cold walls of the chimney, is deposited in the form of water droplets, which roll down the smooth walls of the chimney down into the condensate collector.

The condensate collector is installed outdoors. It is better to assemble a sandwich chimney “by condensate”.

3. Features of penetration through the roof

Penetration through the roof is done according to the same principles as penetration through ceilings. Let's find out if it is correct that when driving through rafters, the distance to protected wooden structures can be reduced to a size of 150 mm.

Alexey Telegin:

– It is assumed that the chimney cools down when passing through the roof, and the space around it is well ventilated, so you can reduce the gap to the protected rafters. In my opinion, this may be true for a cold roof, but with an insulated roof, you need to apply the same standards and distances as for interfloor ceilings.