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.

Content

Before installing a heat source that requires gas, solid or liquid fuel in a private house, bathhouse or outbuilding, it is necessary to prepare a design for a combustion product removal system. Today, classic designs made of brick or asbestos-cement pipes are replacing convenient and practical chimneys made of stainless steel, for the installation of which ready-made elements are used.

Types of stainless steel chimneys

You can connect any type of heating boiler, metal or compact brick stove, or fireplace to the universal modular chimney. You can assemble the smoke channel yourself by choosing the right system. They differ in design, purpose, and metal characteristics.

Main advantages

Chimneys made from asbestos-cement pipes were in demand due to their low cost, despite their low practicality. Brick structures are still actively used today, including due to their solid and impressive appearance, but they are increasingly being modernized with the help of stainless steel inlays. The list of advantages of a chimney made of stainless steel includes:

  • Light weight. The chimney does not require a foundation, which reduces the cost and speeds up installation work.
  • Corrosion resistance. Stainless steel is resistant to acids contained in smoke condensate and dangerous for brick and asbestos cement.
  • Resistance to temperature changes. The metal can withstand cooling to low temperatures on frosty days and heating by flue gases up to 800 degrees Celsius or more.
  • Effective chimney removal. Good traction is facilitated by the round cross-section of the pipe.
  • Low maintenance. There is practically no soot deposited on the internal walls of the chimney channel (unlike rough walls made of brick or asbestos cement), so it rarely needs cleaning.
  • Easy installation. The configuration of standard elements allows for quick assembly of pipes of any length.
  • Maintainability. The modular system allows, if necessary, to change only the element that has failed, which reduces the cost of operating the smoke exhaust system.
  • Long service life (subject to the correct selection of manufacturing materials and proper installation).
  • Versatility. A stainless steel chimney is suitable for any type of heating unit.
  • Freedom of installation. It is not necessary to mount a strictly vertical structure; inclined elements and turns are allowed, which simplifies the search for a convenient place to install a boiler, fireplace or stove. A pipe with internal insulation can be installed outside the building - in this case there will be no need to install passage units through the floors and roof.
  • Affordable price.

Chimney components

Types of pipes

Stainless steel is used to make three types of chimney pipes, each of which has its own specific application. It is important to take this into account when choosing an option for a residential building, bathhouse or other building. Manufacturers offer the following types of designs:

  • single-walled (single-layer);
  • corrugated;
  • sandwich pipes.

Let's take a closer look at which stainless steel chimney pipe would be more appropriate for use in certain conditions.

Single wall pipes

Single-layer systems are made of stainless steel sheet with a thickness of 0.6 to 2 mm. The option is characterized by a low price, but the scope of application of such a pipe is limited.

It can only be installed inside a warm room, and the outer part of the chimney should be insulated. This is due to the fact that contact of heated metal with cold air leads to increased formation of condensation. This reduces the efficiency of the heating unit, entails excessive fuel consumption, and reduces the service life of the stove or boiler.


Single wall pipes

Single-wall steel pipes are most often used to arrange sleeves when modernizing brick smoke ducts. Lining extends the service life of a brick chimney due to protection from destructive condensation, and reduces the need for maintenance, since soot does not build up on the walls. Manufacturers offer single-layer stainless steel pipes of different sizes, round and oval sections, which allows you to choose the best option for a particular brick chimney.

A single-layer pipe can also be used in conjunction with a water heating system for a small room - a garage, workshop, washing department of a bathhouse. In this case, a water jacket is mounted on the chimney pipe, to which the supply and return pipes are connected. Also, the thermal energy of exhaust flue gases can be used to heat a compact room by running a single-layer pipe at an angle along a long wall.

Installation of a chimney made from a single-layer stainless steel pipe requires strict adherence to fire safety rules when arranging passages through the floors and roof. The ignition of soot in a pipe (especially when using a solid fuel stove) can heat the metal to critical temperatures and lead to the fire of wooden structures.

Corrugated pipes

The corrugated stainless steel pipe is designed for installation of curved transitions if the outlet pipe of the boiler or furnace is located away from the vertical chimney channel. Also, when lining a brick chimney, a corrugated pipe can be used inside a structure that has bends.


Corrugated pipes

It is necessary to choose a high-quality corrugated pipe made of stainless steel that can withstand heating up to 900 °C. Corrugated elements are used inside and outside the building, but in the second case they require insulation to avoid the formation of condensation due to contact of the metal with cold air.

Note! A chimney project using corrugated elements may be rejected by regulatory authorities, since there are complaints about the strength and heat resistance of corrugated pipes.

Sandwich systems

A two-layer pipe, which is a sandwich with a non-flammable heat insulator between metal shells made of stainless steel, is produced in the form of straight and shaped elements for assembling a chimney of any configuration. Due to the thermal insulation layer, this is the most practical option for a smoke exhaust duct, because:

  • increased safety is ensured (the outer walls of the system do not heat up to dangerous temperatures, the heat insulator itself is resistant to ignition);
  • allows you to install the chimney outside the building;
  • a minimum of condensation is formed (the internal pipe through which combustion products move does not come into contact with cold air);
  • there is no unnecessary heat loss, which allows the heating unit to operate in optimal mode, without excessive fuel consumption;
  • the system is installed quickly and without the hassle of pipe insulation.

Sandwich system

Sandwich pipes are universal; they are used for installation on gas or solid fuel boilers, fireplaces and stoves of any type.

Range of modules

Installation of a stainless steel chimney is carried out using ready-made modules of various types, so it is not difficult to do it yourself. Manufacturers offer the following elements:

  • Straight pipes. The part can have a length from 33 to 100 cm. The elements are firmly connected to each other through bell-shaped coupling; installation does not require the use of additional fasteners.
  • Bends 45°. They are used when it is necessary to perform a deviation from the vertical.
  • 90° bends. Used to transition between vertical and horizontal sections of the structure.
  • Tee 45° or 87°. Designed for installation of a condensate assembly unit, it can also be used to connect two heating units to a common chimney.
  • Condensate collector. It is mounted at the lower point of the main vertical channel; moisture condensed during cooling of the flue gases flows into it.
  • Revision element. Installed in places where there is a higher risk of soot accumulation, to check and clean the chimney system.
  • Penetrations. Special elements for arranging the nodes for passing pipes through floors and roofs help ensure fireproof insulation of structures, roof tightness, and an attractive appearance.
  • Cap, spark arrester and other elements for installation on the top of the chimney. They protect the system from the penetration of precipitation, the occurrence of the reverse draft effect, and from sparks hitting the roofing.

Chimney elements

Material selection

To make stainless steel pipes for chimneys, various grades of steel are used. The service life of the product and its resistance to burnout when soot ignites in the pipe depend on the choice. The higher the quality of the steel, the more expensive it is. Be sure to take into account the frequency of operation of the chimney - the requirements for the chimneys of boiler units that operate around the clock during the heating season are higher than for the pipes of sauna stoves that are fired from time to time.

steel gradeCharacteristics
439 Titanium and aluminum are used as additives. The material is resistant to acid corrosion and can withstand heating up to 850 °C.
430 Mainly used for the manufacture of casings and other elements that are not directly exposed to high temperatures and aggressive environments.
409 High heat resistance and acid resistance, can be used for chimney pipes of solid fuel stoves and fireplaces.
304 High strength, good weldability. It serves as a cheaper analogue of steel 316, somewhat inferior to its parameters due to the low amount of alloying additives.
310SA universal material due to its ability to withstand heat up to 1000 °C.
316 Thermal stability and chemical resistance are ensured by the addition of molybdenum and nickel. The material is suitable for boiler pipes of any type.
316i, 321Pipes are universal, flexible, and corrosion resistant. Can be used for wood stoves.

Stainless steel material selection

In private housing construction, stainless steel pipes of grades 409, 430, 439 are mainly used. With periodic operation (weekly heating of a sauna stove with wood), such a system will last about ten years. On boilers in load mode 24 hours a day, the average service life will be 2–3 years. To extend the service life of the chimney system, it is recommended to install it from 3XX stainless steel.

Chimney design

The design of a system for the removal of combustion products begins with the selection of a modular system and preparation of the project. Since the requirements for chimneys for gas boilers are increased, their design must be submitted to technical supervision services and permission for installation work must be obtained.

  1. The minimum permissible total height of the chimney is 5 meters, otherwise the draft will be insufficient.
  2. The maximum length of the horizontal section of the channel is 1 meter;
  3. Outside the building and in unheated rooms, the chimney must be thermally insulated, unless it is a sandwich system.
  4. The height of the chimney pipe above the roof:
    • at least 50 cm if the roof is flat or the distance from the ridge of the pitched roof to the pipe is less than 150 cm;
    • flush with the ridge or higher, if the distance from the pipe to the ridge is from 150 to 300 cm;
    • below a line with a slope of 10° from the horizon of the ridge, if the distance between the ridge and the pipe is more than 300 cm;
    • above the level of buildings attached to the building.
  5. If the roofing material is not resistant to fire, regulations require the installation of a spark arrestor.
  6. The minimum distance between a single-wall stainless steel pipe and the floor and roof structures is 1 meter; (for a sandwich - 20 cm), the pipe must be insulated with non-flammable material (basalt wool).
  7. A gap of 13 cm is required between the pipe and the roof (including those made of non-combustible materials).
  8. Pipe connection points should not be located inside structures (ceilings, walls). The minimum distance from the joint to the structure is 70 cm.
  9. Horizontal and inclined sections of the chimney duct must be assembled “according to the smoke” - the next element is put on the previous one so that combustion products are removed as efficiently as possible. The vertical channel is mounted “along the condensate” - so that the moisture flows freely, the subsequent element is inserted into the one located below.
  10. Throughout the entire length of the chimney duct, its internal diameter must be no less than the diameter of the outlet pipe of the heating unit.
  11. No more than three turns are allowed along the entire length of the chimney.

Chimney installation diagram

There are various installation schemes for stainless steel chimneys. In the case of using a sandwich system, it is easier to bring the pipe outside so as not to punch holes in the ceilings and roof. The pipe is secured to the external wall using special brackets. The external chimney can also be mounted inside a metal profile frame to prevent accidental mechanical damage, especially in the case of high wind loads.

Installation features

When installing stainless chimneys, it is important to follow the rules on the basis of which the system is designed. The entire range of work can be completed independently, paying special attention to the following points:

  • A standard adapter must be attached to the nozzle of the heating unit, and not a homemade replacement, as this can lead to problems in the operation of the chimney;
  • additional sealing of pipe joints is required to prevent carbon monoxide from entering the room and to ensure good draft;
  • the sealant must be heat-resistant and withstand heating up to +1000 ... +1500 degrees Celsius;
  • brackets for external installation of the pipe are fastened in increments of no more than two meters, and fastening points must be provided at the point where the chimney passes through the wall and next to the inspection compartment.

Types of installation

Thanks to the special configuration of the edges, you can quickly connect the modules, creating a solid structure. Details on how to properly assemble a stainless steel chimney can be found in the video.

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 site 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.

Correct installation of the chimney is a necessary condition for the normal functioning of the fireplace, stove or boiler. This article specifies the basic installation rules and calculation principles used in the design and installation of chimneys.

The desire to build a house on your own arises, as a rule, from the need to save material resources, because the services of specialized enterprises are not cheap. However, the construction of a chimney requires a special approach: this matter cannot be done without the use of special knowledge. Therefore, let us recall the basic rules for creating effective smoke exhaust systems and the importance of observing them.

Chimney installation rules: what should a proper chimney be like?

Fuel consumption, the amount of thermal energy loss, fire safety and air quality in the heated room depend on how well the chimney functions. Therefore, its design and installation must be carried out in accordance with SNiP “Heating, ventilation and air conditioning”, DBN V.2.5-20-2001 Appendix G “Discharge of combustion products” and other regulatory documents. Let's talk about what a properly designed and installed chimney should be like - here are the basic rules for its creation.

The material from which it is made has a great influence on the characteristics of the channel for removing combustion products. In new buildings, as a rule, pipes made of stainless, acid-resistant steel containing molybdenum are installed. But for stoves and fireplaces that burn wood and coal, ceramic bricks are also quite suitable.

It is preferable that the cross-section of the chimney be a regular circle: this shape creates the least resistance to escaping smoke. The height and cross-section of the chimney are calculated in accordance with building codes; this will be discussed in more detail later.

The correct approach to the horizontal sections of the channel is important: they should not be longer than 1 m, otherwise soot will be deposited and the draft will weaken.

Connecting a heating unit to a chimney pipe often has to be done when the diameters in the connection area do not match. To solve the problem, use a reduction adapter. All joints are carefully sealed.

The pipes are joined in such a way that their extensions are directed upward. This will prevent condensate and resins from flowing down the outer wall of the pipe.

A brick chimney is erected according to a project: the order of masonry must be prescribed for each layer. In this case, one should strive to obtain an internal surface with a minimum of roughness and achieve complete tightness.

An old brick chimney can be used with a new gas boiler only after the liner has been completed: an acid-resistant steel pipe is inserted into the middle of the channel, leaving a small gap.

Most smoke exhaust systems must be equipped with inspections for cleaning.

Thermal insulation of external pipes is mandatory: this will not only get rid of condensation, but will help to quickly warm up the pipe.

When the channel passes through the ceilings, it is necessary to take measures to isolate the heated parts from flammable materials.

The outer part of the pipe is securely fixed and protected from the wind. The upper part is protected from precipitation with weather vanes or deflectors. The exception is gas equipment: in this case, installing a protective cap is a violation.

What is an irregular chimney?

Correcting mistakes made during the construction of a chimney is very difficult and expensive, and sometimes even impossible without dismantling the old system. Here are examples of the most common errors and their consequences:

  1. The use of materials not intended for the construction of chimneys. Thus, the use of brick is unacceptable for gas boilers: the acid contained in combustion products will destroy it within several years. Asbestos-cement pipes should also not be used: when heated, they are destroyed. Plastic also cannot withstand high temperatures.
  2. Errors in choosing the pipe diameter and calculating the height of the chimney can result in a lack of normal draft and low system efficiency.
  3. Excessive loads on the base of the chimney can cause its destruction.
  4. Weak thermal insulation is the cause of condensation and fire of nearby materials.

Chimney height: depending on the angle of the roof and the distance to the ridge

Ceramic bricks, previously used for the construction of chimney pipes, are increasingly being replaced by systems made from other materials. The most commonly used steel pipes are bare and insulated. In this case, the option without insulation can only be used for internal installation - in a specially constructed shaft. External installation of the pipe requires mandatory insulation, otherwise condensation will inevitably form on the internal surfaces.

In order to determine the height of the chimney for an industrially manufactured boiler, you should use the formula: h(m) = (∆p ⋅ Tp ⋅ Tn) / (3459 ⋅ (Tp - 1.1 ⋅ Tn)), Where ∆p(Pa) - static thrust, Tr- average temperature in the middle of the pipe (in Kelvin), TN— average outside air temperature. Temperature in the pipe (Tr) can be found out based on measurements at the boiler outlet and is indicated by the manufacturer in the technical data sheet of the heating equipment. In this case, natural cooling per meter of chimney is taken into account: in a brick chimney - 1 degree, in an insulated steel chimney - 2 degrees, in a steel without insulation - 5 degrees. Outside temperature (Tn) should be summer: at this time the draft will always be weaker than in winter.

However, the results of calculating the height of the chimney in some cases need to be adjusted, but only upward. The fact is that the house itself sometimes turns out to be higher than the obtained chimney height value. In this case, the rule that says:

  • the chimney, located at a distance of up to 1.5 m from the ridge, must be at least 0.5 m higher than it;
  • if it is located within 1.5-3.0 m from the ridge, then its top should not be lower than the ridge;
  • at large distances from the chimney outlet to the ridge, the height of the pipe is chosen such that it is not lower than a line drawn from the top of the house down at an angle of 10 degrees.

Chimney height above roof

For solid fuel and gas boilers, the chimney height must be at least 5 m: usually, manufacturers indicate this parameter in the accompanying documentation. It should be remembered that the tall pipe should be secured additionally - with the help of guy wires.

But that’s not all: if there is another, taller building next to the house, then the chimney must be installed higher than the roof of the neighboring building.

Cross-sectional area

The value of this parameter can be calculated by knowing the height of the chimney h(m) and the thermal load of the burner according to the formula: S = (K ⋅ Q) / (4.19 ⋅ √h), Where TO- empirical coefficient, numerically equal to 0.02-0.03, and Q(kJ/h) - device performance indicated in the passport, h(m)- chimney height.

If you act more simply, without formulas, then you should take as a basis the following values ​​for the cross-section of a smoke exhaust duct made of brick (the cross-section of round ducts should be exactly the same area):

  • for a unit with a power of up to 3.5 kW - 140x140 mm;
  • for power from 3.5 to 5.2 kW - 140x200 mm;
  • for power from 5.2 to 7.2 kW - 140x270 mm.

Significant excess of the calculated value leads to deterioration of traction and, as a consequence, to unstable operation of heating equipment. A smaller diameter threatens poor removal of carbon monoxide and other combustion products and even a complete cessation of this process.

Additional requirements for chimneys for stoves, fireplaces, solid fuel, gas boilers and geysers

Some rules not mentioned earlier that should be followed:

  • the use of a solid fuel stove requires mandatory compensation of exhaust ventilation with the help of supply ventilation;
  • chimney ducts can be located in external walls if they are built from non-combustible materials, but insulation from the outside should be provided to prevent the formation of condensation;
  • for each stove (if they are located on different floors) a separate pipe is provided, but it is allowed to use one pipe for two stoves located on the same floor: at the junctions of the pipes, cuts with a height of 1 m or more and a thickness of 12 cm are installed;
  • smoke ducts made of bricks should be constructed with pockets for cleaning, which are closed with bricks laid on edge and covered with clay mortar (doors can be installed);
  • if necessary, deviations of pipes from the vertical are allowed at an angle of up to 30° and the length of the section is not more than 1 m, while the cross-section of the channel must be the same;
  • if the roof is made of flammable materials, a mesh spark arrester is installed in the upper part of the chimney;
  • between chimneys made of brick or heat-resistant concrete and roof parts built from combustible materials, there should be equal to or more than 130 mm, for uninsulated ceramic pipes - 250 mm, for them with insulation - 130 mm;
  • the top of the chimney for the fireplace is protected with a weather vane or fungus;
  • two appliances operating on gas may be connected to a common duct for removing combustion products if these appliances are located no further than 750 mm from each other;
  • The cross-sectional area of ​​the chimney connected to the gas appliance should not be less than the cross-sectional area of ​​the gas outlet pipe of the appliance itself, and the upper part of the pipe is not covered with a canopy.

Information from regulatory documents establishing the rules for the design and installation of chimneys

Frost-resistant clay bricks are suitable for laying chimneys. It is strictly prohibited to build channels from slag concrete and other similar materials.

For connecting gas appliances to chimneys, connecting pipes made of galvanized or roofing steel with a thickness of 1 mm or more are suitable. You can also use flexible corrugated metal pipes that come with the equipment. In this case, it is important that the connecting pipe has a vertical section, the length of which from the lower level of the pipe to the axis of the horizontal section of the channel should not be less than 0.5 m. If the ceiling height is less than 2.7 m, this distance can be reduced by half - for equipment equipped with traction stabilizers and up to 0.15 m - for devices without stabilizers. The total length of horizontal sections in newly built houses should not be more than 3 m; for old buildings 6 m is allowed. It is necessary to maintain a slight slope of the pipe towards the heating device.

Smoke exhaust ducts should not have more than three turns, and the radius of curvature should be equal to the diameter of the pipe. It is prohibited to route the chimney through residential premises.

How to care for a chimney

If the thickness of deposits on the inner surface of the pipe exceeds 2 mm, it’s time to start cleaning. You can get rid of dense dirt using a scraper and a stiff brush with a long folding handle: as you move deeper into the canal (work starts from the top), the length of the handle increases.

The combustion hole must be closed from below: this will prevent soot from entering the room. In addition, it is advisable to cover furniture with film and lock doors and windows. During operation, you can use chemical detergents, for example, “miracle logs”, which during combustion emit a special non-toxic gas, from which carbon deposits lag behind the surface of the pipe.

There are also effective folk remedies. For example, it is sometimes recommended to heat the stove with aspen wood: this creates a high flame that burns deposits on the walls of the pipe. But this should be done carefully: a large amount of soot can cause a fire. You can also burn potato peels: the steam that is generated is an effective remedy for soot deposits.

Conclusion

The requirements set out in the article are mandatory. Otherwise, the chimney will be ineffective and even dangerous. This information will serve as a useful reminder for those who already have some experience working with chimneys. For those who do not know it, the material in the article should convince them of the need to take the details of the chimney creation process seriously. Don’t overestimate your capabilities: to avoid annoying mistakes, you should seek help from professionals.

Dmitry Portyanoy, rmnt.ru

In this article we will talk about how to correctly calculate the dimensions and how to assemble a sandwich chimney with your own hands. All figures given in the article are based on the requirements of building codes that relate to heating, ventilation and air conditioning.

A chimney is necessary for houses if they are heated by a fireplace, stove or gas boiler. Its main task is to remove combustion products outside. In this case, all safety standards must be observed.

Due to the simplicity of its design, assembling a sandwich chimney does not seem to be a difficult task. And thanks to its special design, the chimney does not require frequent maintenance, and its service life is quite long.

We calculate the correct dimensions for the chimney

The exact installation diagram of a sandwich chimney depends on the overall dimensions of the pipe required for normal smoke exhaust. To do this, it is important to calculate the cross-sectional dimensions and length of the pipe.

Determining the dimensions of the pipe section

  • 0.14*0.14 m with boiler thermal power up to 3.5 kW;
  • 0.14*0.20 m with power from 3.5 to 5.2 kW;
  • 0.14*0.27 m with power from 5.2 to 7 kW.

That is, the cross-sectional dimensions depend directly on the thermal power of the heating equipment. The above parameters will help you choose the section size yourself. If a round pipe is used as a chimney, then its area should be equal to the cross-sectional area of ​​a rectangular pipe for a certain boiler power.

All sandwich chimney elements must have a certain length.


  • in accordance with SNiP 41-01-2003, the height of the smoke trap pipe should not be less than 500 cm;
  • the chimney pipe is installed above the ridge by 50 cm or more;
  • if the roof of the house is made of flammable material, it must be at least 1 m;
  • if there are extensions whose roof height is higher than the main building, the chimney pipe is installed above this extension.

The influence of the pipe location on its height:

  • For a flat roof, the pipe should be installed 50 cm higher from the roof surface.
  • If the chimney pipe is located close to the ridge (up to 150 cm), then its height should be 50 cm above the ridge.
  • If the pipe is located at a distance of up to 3 m from the ridge, then it can be brought out flush with the ridge, the main thing is to understand how to assemble a chimney from sandwich pipes.
  • If the chimney is located far from the ridge (more than 3 m), then the end of the pipe can be brought below its level (the line drawn from the ridge to the end of the chimney should have an angle to the horizon of up to 10 degrees).


Based on the instructions above, you already know how to properly assemble a sandwich chimney.

Important aspects of chimney installation

Before installing the sandwich, it is necessary to check some aspects of the heating system.

It is important to know the following:

  • chimney pipes should not have ledges;
  • the temperature of the gases rising through the pipe should not be more than 500 degrees (read also: " ");
  • pipes can be moved to the side at an angle of 30 degrees;
  • inclined sections of the chimney should not have any roughness. The cross section must have an area not less than the vertical one.


In addition, it is important to protect the chimney itself from precipitation. The function of such protection is performed by a deflector, umbrella and other similar attachments. It is also important to remember that it is strictly forbidden to lay electrical wiring or other communications in close proximity to the chimney.

Sandwich chimneys: instructions

  • Attaching a sandwich chimney starts from the fireplace or stove. The first link of the pipe is connected to the outlet pipe of the heating device. The gaps are closed with a plug. Read also: "".
  • The pipes are inserted into one another. You will immediately notice how this needs to be done, since one edge of the pipe is always narrower than the other. This method of collecting pipes allows the resulting condensate to fall down unhindered.
  • It is important not to forget that not only the outer but also the inner pipe must be joined. Connecting both pipes at the same time is quite a difficult task. In order to carry out this procedure, it is enough to simply release the inner pipes outwards with an overhang of 15 cm. This allows you to easily connect them. And only after that the external pipes are joined.
  • The resulting joint must be strengthened. To do this, take a galvanized clamp, which is wrapped around the joint. Then we tighten the clamp with nuts, bolts or wire. A layer of sealant that is resistant to high temperatures is applied to the pipe (stability margin is up to 1000 degrees).


The chimney sandwich is almost assembled. Next, using the same principle, they begin to attach the tee, corners, tip and umbrella. Every 2 meters, sandwich ferrum chimneys are attached to the wall. must be quite reliable; brackets are used for this. The tee is attached to the wall with support brackets. This allows you to reduce the load on the chimney riser. If necessary, you can install horizontal chimney links, but then their length should not be more than 1 meter.

During installation, it is important not to forget to remove the film that covers the sandwich pipes.

What is a derogation

Like any other chimney, our design needs so-called setbacks. This term should be understood as the space formed between the wall and the smoke exhaust duct. The size of the setback is taken in accordance with building codes.

Table - Sandwich chimney sizes


If the setback is placed in the walls, then two holes should be arranged at different levels. Each such hole must be protected with a mesh and have a cross-section of at least 150 sq.cm. In a closed retreat, the floor is made of non-combustible materials. At the same time, it is raised 7 cm above the level of the main floor.

Passage through floors

Overlappings are carried out using the so-called cutting. At the point where the chimney comes into contact with the structure of the house, it is necessary to install a special link. Often this is a box with a hole or a pass-through pipe.

The cutting size is made 7 cm larger than the thickness of the ceiling. Its main task is to protect wooden and, therefore, flammable structures from fire (more details: ""). In this case, the cutting does not need to be rigidly connected to the structure of the house. The pipe in the pipe is selected so that it does not have joints.