The correct installation of a chimney for a gas boiler in a private house is the basis for high-quality heating operation. It is necessary to strictly follow the rules and regulations here, since otherwise it may jeopardize the safety of the residents of the house. Let's take a closer look at how chimneys for gas boilers are installed: requirements and recommendations in our article today.

Regardless of the location of the chimney, there are certain installation rules

Requirements for chimneys and installation rules

Installation of a chimney and ventilation for a gas boiler occurs in compliance with the chimney installation standards SNiP 2.04.05, and the manufacturer’s recommendations are taken into account:

The size of the channel is chosen to be the same as that of the boiler socket or slightly larger. The height of the pipe is at least 5 meters.

In rooms with traditional hoods, the exhaust air is replaced by air coming from the street and partly from other adjacent rooms.

The chimney is made of non-combustible material.

Important! It is prohibited to use the ventilation duct to exhaust smoke.

After putting a gas boiler or other equipment with a chimney into operation, a chimney inspection report is drawn up.

Requirements for installing a chimney

Installation work is carried out by specialists using all regulatory rules. They are as follows:

Every heating unit has a single chimney outlet.

Free and complete exhaust of smoke into the atmosphere is ensured due to the correctly selected height and cross-sectional size of the pipe (clause 5.1.1.VDPO).

The wall thickness of the metal pipe is not allowed less than 2 mm.

To make a pipe, metal with a thickness of 2 mm is taken

To clean smoke channels from soot, recesses with a size of about 250 mm are provided (clause 3.74 of SNiP-91 and clause 5.1.1.VDPO).

When installing a pipe, the smoke channels are made taking into account no more than three turns, and their rounding is equal to the diameter of the pipe (4.2.17.VDPO).

The chimney for a gas boiler in a private house and the exhaust pipe are installed above the roof ridge in accordance with clause 3.73.SNiP-91: up to 0.5 m - with a flat roof; at the level and above the roof itself - when the pipe is located more than 1.5 meters from the roof ridge.

Metal chimneys are made of high-quality alloy steel with anti-corrosion coating.

Types of chimneys

Pipes are made from different materials, which we will consider in more detail.

Brick

Classic brick chimneys for gas boilers are still in demand, regardless of their many disadvantages and weak thermal characteristics. At the same time, they meet sanitary standards and rules, which state:

The pipe is made of fireclay bricks.

To build the walls, a clay solution or special glue is used.

To improve draft, the chimney rises above the level of the roof ridge.

Standards regulate the height of the pipe in relation to the roof ridge depending on the distance between them

The masonry ensures tightness.

At the internal hole, the deviation is no more than 3 mm per 1 m.

To protect against precipitation, a deflector is installed on the head of the pipe.

The chimney can also have a mono design, which, due to low thermal characteristics, is repaired every 5-7 years.

On our website you can find contacts of construction companies that offer house insulation services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

Galvanized pipe

The “sandwich” type device today is the most effective option for chimney designs. The undoubted advantage of these chimneys is their resistance to aggressive environments and various mechanical influences.

The product consists of two pipes of different sizes, with one inserted into the other. Basalt wool is usually used as a filler between them.

Currently, gas boilers use closed combustion chambers. Here, air enters and smoke is exhausted by a coaxial pipe. This is an original device, relatively recently introduced, but already very popular among users.

The non-standard solution lies in the supply of air through a pipe that removes combustion products. It turns out that one pipe performs two functions due to the design features.

A coaxial chimney is a pipe in a pipe

And its characteristic difference from ordinary pipes is the following... A smaller pipe (60-110 mm) is located in a larger diameter pipe (100-160 mm) in such a way that they do not touch each other.

At the same time, the structure is a single whole due to jumpers along the entire length and is a rigid element. The inner pipe serves as a smoke exhaust, and the outer pipe serves to supply fresh air.

Air exchange at different temperatures creates draft and sets the air mass in directional movement. The air in the room is not used during operation of the boiler, thus maintaining the microclimate in the room.

Ceramic

Such a chimney is a composite structure that includes:

Smoke exhaust duct made of ceramic material.

A layer of insulation or air space.

Expanded clay concrete outer surface.

This complex design is due to several reasons. First, the chimney pipe is too fragile to be left unprotected.

The ceramic pipe is always located inside some solid block

Secondly, ceramics have high thermal conductivity, and therefore it needs reliable insulation. The inner round pipe has a smooth surface, while the outer one has roughness that does not affect the integrity of the product.

Typically, such chimneys are produced in lengths from 0.35 to 1 m, depending on the manufacturer. The connection of the inner and outer pipes occurs through a lock, which is a thinning in outer size at one end and an expansion of the inner pipe at the other end.

Important! The joining of these pipes is carried out strictly along the axial line.

The expanded clay concrete outer surface is made of a square shape with a round hole inside. In addition, this product provides space for insulation, which is held in place by metal bridges. At the same time, they are fixed on the outer surface and make the pipe securely fastened.

Stainless steel

A steel gas chimney seems to be more reliable than a brick one. They are resistant to corrosion, immune to temperature fluctuations, and are not affected by increased air humidity and aggressive environments.

In addition, such stainless steel pipes have a number of advantages:

Long period of operation.

Multifunctionality.

Relatively low cost.

Great strength.

Possible implementation of a product of any complexity.

Chimneys made of this material are characterized by an assembly of modules, which allows the replacement of a damaged segment if necessary. The installation of chimneys is done using special outlets that allow them to fit harmoniously into certain roof elements.

Main mistakes when choosing a flue for a gas boiler

The most common mistakes when installing a pipe for a gas boiler in a private house are:

Incorrectly chosen height and cross-section of the pipe.

Lack of heat-insulating material when installing an external chimney or in a transition hole into an unheated attic space.

Failure to comply with fire safety standards (fire safety rules).

The pipe removing gas from the boiler is led into the brick channel shaft without liner, which leads to the rapid destruction of this hole.

Installation of steel chimneys made of material that does not meet the requirements (resistance to aggressive environments, high temperatures or thin walls).

Video description

To see several rules for choosing chimneys, watch the video:

Chimney installation is divided into several stages - preparatory work, installation itself, then connection, startup and, if necessary, debugging of the entire system.

General requirements

When several heat-generating installations are combined, each of them creates its own chimney. In exceptional cases, a tie-in to a common chimney well is allowed, but a difference in height of at least one meter must be maintained.

First, the chimney parameters are designed and calculated, which are based on the recommendations of gas boiler manufacturers.

When summing up the calculated result, the internal cross-section of the pipe cannot be less than the diameter of the boiler outlet pipe. And according to testing according to NPB-98 (fire safety standards), the initial speed of the natural gas flow should be 6-10 m/sec. And besides, the cross-section of such a channel must correspond to the overall performance of the unit (8 cm 2 per 1 kW of power).

Installation steps

Chimneys for gas boilers are mounted outside (attached system) and inside the building. The simplest is the installation of the outer pipe.

Installing a chimney on a wall-mounted boiler is done as follows:

A hole is cut in the wall. Then a piece of pipe is inserted into it.

The vertical riser is assembled.

The joints are sealed with a fireproof mixture.

Fixed with wall brackets.

An umbrella protecting from precipitation is fixed on top.

An anti-corrosion coating is applied if the pipe is made of metal.

Proper installation of the chimney guarantees its impermeability, good draft, and does not allow soot to accumulate. Installation performed by specialists will significantly reduce the cost of maintaining this system.

When constructing an opening for a pipe in the roof of a house, special boxes with aprons are used. In this case, the design as a whole is influenced by such factors as:

The material from which the pipe is made.

External design of the chimney.

Type of roof covering.

The main factor influencing the choice of design is the temperature of the gas that passes through the pipe. At the same time, according to standards, the distance between the chimney pipe and combustible materials must be at least 150 mm. The most advanced assembly system is considered to be in segments, where all elements are assembled using the cold forming method.

Video description

How to install a chimney pipe, see the following video:

Connecting a ceramic chimney

Ceramic chimneys themselves are practically eternal, but since this is a rather fragile material, you need to clearly understand how to correctly connect (docking) the metal part of the chimney and the ceramic one.

Docking can be done only two ways:

By the smoke– a metal pipe is inserted into a ceramic one. It is important to remember here that the outer diameter of the metal pipe should be smaller than that of the ceramic one. Since the thermal expansion of metal is much greater than that of ceramics, otherwise the steel pipe, when heated, will simply rupture the ceramic one.

For condensate– a metal pipe is placed on a ceramic one.

For both methods, specialists use special adapters, which, on one side, are equipped with a gasket for contact with a metal pipe, and on the other, which contacts directly with the chimney, are wrapped in a ceramic cord.

The joining should be carried out through a single-wall pipe - it has a higher heat transfer coefficient. This means that the smoke will have time to cool down a little by the time it reaches the adapter, which ultimately extends the service life of all materials.

Video description

Learn more about connecting to a ceramic chimney in the following video:

Conclusion

VDPO shows great demands on chimneys for gas boilers, which is why installation must be carried out by specialized teams. Since proper installation guarantees not only long-term operation of the device, but also makes living conditions in a private home safe.

To ensure a pleasant life in a cottage in winter, eliminating the occurrence of dangerous situations, it is necessary to develop and install a competent heating system. Of all types, gas is the most economical. However, when selecting and installing equipment of this type, it is necessary to strictly adhere to the existing set of rules. Then your stay will be not only comfortable and cost-effective, but also safe. At the same time, it is important to correctly install a chimney for a gas boiler in a private house, because the required heat transfer of the boiler largely depends on its throughput, tightness and safety.

Read in the article:

Chimney for a gas boiler in a private house: purpose, features

When designing heat supply for houses and cottages, you need to wisely choose chimneys for boilers that remove hot air containing harmful substances. The task is important, therefore the following requirements are put forward to such elements of the system:

• Ensuring sufficient traction.

The main thing is to correctly position and select the diameter of the chimney for the gas boiler.

• Elimination of deformation and damage under the influence of high temperature of the transported medium.

The temperature is quite high, so the chimney pipe for a gas boiler must be made of heat-resistant material.

• There should be no change in the properties of the material due to chemical exposure.
• Suitable shape.

Nowadays, round pipes are more common, since less soot lingers on their walls.

Basic requirements for installing a chimney in a private house

If you install a chimney in a cottage yourself, study and strictly adhere to the rules described in the following regulatory documents:

• SNIP 40-01-2003.
• SNIP 42-01-2002.

At the same time, the most important points that must be taken into account when installing a chimney are: correct calculation of the smoke removal system, that is, the height and diameter of the chimney for a gas boiler; selection of pipe material; frequency of service work (cleaning and routine repairs).

In addition, the fire safety regulations clearly define the requirements for the chimney of a gas boiler. Of course, every year they change somewhat, but general provisions can be highlighted:

• The room in which the gas boiler is located must be sufficiently ventilated, that is, an exhaust ventilation device (mechanical or natural) is necessary. In this case, the chimney is strictly prohibited from being led into an exhaust shaft. Combustion products from several boilers can be discharged into one chimney; the main thing is that the room must be of sufficient volume (height - at least 2 meters, area - 7.5 meters per boiler), and the chimney is strictly prohibited from being blocked by any gratings.
• Equipment located in different boiler rooms cannot be combined into one chimney. If it is located in the same room, such a device is allowed with two reservations: the boilers must be connected to a chimney located at a distance of more than 100 cm in height from each other; installation of a cutting device is required.
• It is necessary to comply with fire safety standards when crossing a partition that is susceptible to fire. That is, when crossing wooden partitions, it is necessary to install fireproof cuts. In addition, you need to leave a small distance between the pipeline and flammable materials (for example, insulation) of at least 5 centimeters. Sandwich pipes are excellent for this purpose and do not require additional work in this case. The load-bearing combustible structures must be more than 100 cm from the pipe. This condition is fulfilled by horizontally tapping the channel. The main thing is not to make such a section too long, otherwise the system may not work correctly.
• It is necessary to comply with fire safety requirements for the construction of combustible floors. Beams and walls located near the chimney must be treated with special fire-retardant solutions, the fire resistance of which is at least 120 minutes.

• To pass through the roof of the building, a special passage must be installed. In the case of ceramic and sandwich pipes, this is quite simple; the necessary element is included in the standard line of materials.
• The maximum length of all horizontal sections should be no more than 3 meters.
• When installing a steel chimney, it is necessary to insulate it, and it is also prohibited to install it with breaks or leaky connections inside the building.

Related article:

As part of this review, we will try to sort it out. How to choose the best option and set priorities for ordinary users, what models exist, how to properly carry out installation on your own.

Features of chimney installation in a private house: calculation of diameter and height, choice of insulating material

How to make a chimney correctly so that it works correctly and for a long time? When installing an exhaust pipe for a gas heating boiler, it is necessary not only to adhere to fire safety rules, but also to make the correct calculations of the height and diameter of the pipe. Since the quality of traction, and therefore the safety of removal of combustion products, depends on these parameters.

If you are not confident in your own abilities, you should entrust this calculation to professionals. However, SNIP contains rules, after carefully studying them, you can calculate the length and diameter of the pipe for a gas boiler yourself.

• To ensure the necessary draft, it is necessary to install a chimney of at least 5-7 meters.
• The height of the part of the pipe protruding above the roof depends on the distance from the ridge of the building.

• It is necessary to take into account the speed and direction of the wind at the point where the pipe exits on the roof, since in some cases it is possible to blow combustion products almost vertically downwards, which will lead to noticeable inconvenience.

Interesting! Some modern gas boilers are equipped with a draft sensor. If it often shows an error, the height of the pipe is not selected correctly, and it is necessary to increase it or move the chimney.

Rules regarding chimney diameter:

• In most cases, the diameter of the chimney pipe should be equal to the size of the boiler outlet. However, if a very high duct is required, the diameter may need to be increased to prevent unnecessary resistance.

• Under no circumstances should the channel be narrowed. For example, if the outlet from the boiler is 200 mm, then the pipe must be at least 200 mm.

Important! Ventilation of the boiler room is necessary to prevent the accumulation of gases in the room when the device is turned off. The main thing is to choose the right cross-section of the exhaust duct.

Another important point when installing a gas pipe is its insulation. This must be done to prevent condensation from forming and pouring into the boiler. The main purpose of the insulation is to retain the outside cold, so that when warm air moves inside the pipe, the walls heat up as quickly as possible, and the air does not cool to the “dew point”. You can insulate flues for gas boilers using one of the following methods:

• Screwing and securing basalt wool onto the pipe using clamps.
• Covering the surface of the chimney with basalt shells is the best option, as they have the best thermal insulation properties.
• A brick chimney is usually insulated with cardboard or basalt mats, since in this case this option is the simplest. After installation, the mats are covered with an even layer of plaster.

Choosing a chimney for a gas boiler: materials

If you decide to install a chimney for a gas boiler yourself, first of all you need to choose the material from which it will be made.

Each of the options listed below has its own advantages and disadvantages. Therefore, usually only one of the types is ideal for a particular case:

• Coaxial.

• Made from stainless steel.

• Brick.

• From asbestos-cement pipes.

So that you can correctly choose what to make a chimney from in a private house, we will analyze each type separately.

Features of coaxial chimneys for gas boilers

A coaxial chimney is one of the types of metal or plastic pipes. It is made in the form of a structure of two pipes of different sizes (the smaller one is inserted into the larger one), and there are jumpers along the entire length that prevent them from touching, in order to achieve maximum efficiency. You can buy a coaxial chimney for a gas boiler at any specialized store, but its cost is quite high, so it is used only in extreme cases.

The principle of air movement through such a pipe is somewhat different from the standard version. The supply air enters the firebox not from the room, but through the outer contour of the pipe, while combustion products are released through the inner contour. Thanks to this device, coaxial chimneys have the following advantages:

The overall heat loss of the building is reduced, because in this case the air to maintain the combustion of the firebox does not come from the room, but is heated by the air removed (recovery principle).

The possibility of a fire in places where the pipe comes into contact with the building structure is reduced due to the isolation of the hot pipe.

High efficiency, due to which a minimum amount of pollution enters the atmosphere.

In this case, only closed-type cameras are used, which are the safest. In addition, the size of such a device is much smaller, which allows you to arrange a boiler room of a minimum area.

This option also has disadvantages:

High price of coaxial chimneys for gas boilers.

Limitation on the length of pipes located horizontally (maximum 2 meters).

Interesting! Such pipes are usually used when using gas boilers without a chimney. Since their installation is the only way to remove heated air without installing a complex chimney system.

Stainless steel chimney: features, advantages and disadvantages

The use of simple stainless steel chimneys for gas boilers is a rather rare case. Since they are susceptible to corrosion, they heat up quickly, which means they are a fire hazard. The only option is to use acid- and heat-resistant metal pipes. They are slightly more expensive, but more reliable and durable. In addition, their thickness does not exceed 0.5-0.6 mm, due to which a chimney made of this material is quite lightweight and can therefore be attached directly to the walls of the building.

The main thing when installing a galvanized chimney is to securely secure the pipe outside the building using an additional supporting structure. If this is not done, a strong gust of wind may simply blow it away.

Advantages of galvanized pipes:

Aesthetically attractive appearance.

Smoothness of the inner surface, due to which less soot settles on it (compared to a brick chimney).

Installation can be done both inside and outside the building. The main thing here is high-quality insulation of the channel.

There is no need to build a foundation for the channel (due to its low weight).

Brick chimney

The most common and reliable way to remove hot air is to install a brick chimney for a gas boiler. The main thing is to correctly calculate its size and location at the building design stage. If a mistake is made and the system does not work correctly, it will be almost impossible to make changes to the design.

Advantages of brick structures:

Price.

With proper calculation, the costs of installing this type of chimney will be minimal in comparison with other types.

Heat accumulation ability.

Fire resistance.

Brick does not burn, so even if a fire occurs, the fire will not spread throughout the building.

Durability.

Flaws:

Heavy weight.

Soot settling on the channel walls due to the roughness of the inner surface.

Lack of resistance to acidic environments.

Structural destruction due to strong temperature changes.

Chimney made of asbestos-cement pipes

Installing a chimney for a gas boiler from asbestos-cement pipes is not very easy to install, but is an inexpensive option. These non-metallic pipes are connected to the boiler using standard fittings. In this case, it is necessary to install a condensate collector in the lower part, and a roof umbrella in the upper part to prevent flooding of the pipe during rain. Such air ducts are installed on special supports made of brick or metal. The main thing is to correctly calculate the load to avoid collapse of the structure.

Most often, a separate chimney of this type is provided for each boiler. The main thing is to insulate the pipelines well so as not to get burned, and to mount the condensate collector in the right place.

How to properly make a chimney for a gas boiler in a private house with your own hands?

Before installing a chimney for a gas boiler, you need to correctly calculate its dimensions and height. Installation must be carried out strictly following the proposed plan. Otherwise, backdraft or rapid destruction of the structure may occur. In addition, it is necessary to decide on the material and location of the structure. After all, the need for insulation and installation features depend on these parameters.

Installation of metal pipes occurs according to the plan below:

• Preparatory stage.

Includes purchasing the necessary materials and applying markings to the floors of the building in the places where the chimney will pass.

• Drilling holes for pipes
• Connecting the boiler to the chimney using an adapter.
• Extending the pipe to the required length.
• Installation of passages through ceilings.
• Strengthening joints with clamps and self-tapping screws.
• Attaching the pipe to the walls of the building using clamps (step – 2 meters).
• Installation of a roof umbrella.

• Chimney insulation.

If the installation is carried out correctly, repairs to the chimney for a gas boiler will need to be carried out after a very long period of time. Therefore, if you are not confident in your abilities, entrust this work to professionals.

Upon completion of installation, the question arises: how to check the draft in the chimney of a gas boiler, and is everything arranged correctly? Indeed, if there is insufficient draft, not only the formation of condensation can occur, but also the flow of gas into the house or the burner extinguishing.

You can check traction in the following ways:

• Using an anemometer.
• Holding a piece of paper up to the chimney.

If the draft is insufficient, it is necessary to suspend the operation of the equipment and not turn it on until the errors in the installation of the chimney from the gas boiler are eliminated.

Price table for chimneys for gas boilers

You can buy a chimney for a gas boiler at any specialized store. In this case, the price mainly depends on the pipe material and the number of fittings. Below is a table of average prices for different types of chimneys.

Conclusion

Errors when choosing and installing a chimney for a gas boiler in a private house can lead to an emergency. Therefore, if you are not confident in your calculations, contact a professional.

Type	Diameter, mm	Length, m	Average cost, rub.
Coaxial	100	0,75	3200
Stainless steel	120	1	550
From asbestos cement pipe

A chimney is an essential part of the heating system of a private home. It ensures the proper functioning of the stove or boiler and organizes the removal of harmful combustion products outside the home.

We will try to figure out how to install a chimney with our own hands so that heating communications are safe for both people and the home.

The installation of heating devices is subject to the requirements set out in the regulatory documentation.

Installation of devices is regulated by the provisions SNiP 2.04.05–91 And DBN V.2.5-20-2001. Also, before drawing up a project, it is advisable to study materials about heating systems ( SNiP 41-01-2003), about heat generation devices ( NPB 252–98), on technical conditions for the operation of thermal devices ( GOST 9817–95), on the rules and regulations for the operation of smoke ducts (VDPO).

The design of the chimney and installation features must fully comply with the requirements specified in SNiP, otherwise you will not receive a construction inspection certificate, which is issued after commissioning

Some of the requirements are addressed specifically to the installation of chimneys. The design of the structure can be anything, but the material must be non-flammable.

The materials used for the construction of chimneys can be:

• steel;
• ceramics;
• brick.

Without exception, all structures are prefabricated, and the installation itself is fragmentary, since the chimney passes through several rooms (for example, a room and an attic).

In order for a structure to meet fire safety requirements, its parameters must be correctly calculated, and all component parts must be sized accordingly. When installing factory equipment, you must follow all the recommendations set out in the instructions, including the assembly procedure and methods for installing parts.

Image gallery

Transitions through floors and roofs require the use of fire-retardant thermal insulation materials, such as mineral wool, and the installation of protective blocks, which can be called a “sandwich within a sandwich”

Construction of a chimney for a gas boiler, stove or fireplace is a responsible task that requires special permission, design and professional skills. If you are not confident in your abilities, entrust the installation of the pipe to specialists who will carry out the work taking into account all norms and requirements.

If you have already built a chimney yourself or are an expert in this matter, please share your experience and knowledge with our readers. Tell us about the nuances of building a chimney in the block below.

The efficiency and safety of a heating device that produces heat by burning a particular fuel largely depends on the parameters and condition of the chimney. Today, many companies have started producing insulated steel models, but not all users are ready to put up with their high cost and relatively short service life. Often, homeowners decide to build a chimney pipe using traditional technology, that is, from brick, with their own hands. To do this, you need to follow some rules and know what materials are best to use.

Strengths and weaknesses of a brick chimney

Brick chimneys can be used in any facility, be it a boiler room or a private house. With the advent of prefabricated steel sandwiches, they have become less popular, but are still widely used. This is explained by the following advantages:

• a brick chimney is cheaper than a “sandwich”;
• lasts longer: approximately 30 years;
• is an important architectural element and ideally combines visually with certain types of roofing, such as tiles.

But this design also has plenty of disadvantages:

1. In terms of complexity and duration, the construction of such a chimney is inferior to the installation of a “sandwich”, and special transport will be required to deliver the materials.
2. A brick chimney has significant weight, so it must be provided with a reliable foundation.
3. It has a rectangular shape in cross-section, although the most suitable is a round cross-section. Whirls form in the corners, preventing the normal flow of gases and thus worsening traction.
4. The inner surface of a brick chimney, even if finished with plaster, remains rough, as a result of which it becomes covered with soot more quickly.

Unlike stainless steel, brick is quickly destroyed by acid condensation. The latter is formed if the temperature of the flue gases during their movement through the pipe manages to drop below 90 degrees. Therefore, when connecting a modern, economical boiler with a low-temperature exhaust or a stove operated in smoldering mode (heat generators of the Professor Butakov, Bullerjan, Breneran brands) to a brick chimney, it is necessary to line it, that is, install a stainless steel pipe inside.

Elements of a brick chimney

The design of the chimney is very simple.

The smoke exhaust duct is protected on top by a cone-shaped part - an umbrella or cap (1), which prevents precipitation, dust and small debris from getting inside. The upper element of the pipe - the head (2) - is wider than its main part. Thanks to this, it is possible to reduce the amount of moisture that gets into the lower area - the neck (3) during rain.

Above the roof there is another widening - an otter (5). Thanks to it, atmospheric moisture does not enter the gap between the chimney and the roofing (6). A slope (4) is formed on the otter using cement mortar, along which the water that gets onto the pipe runs off. To prevent the rafters (7) and sheathing (8) from catching fire from contact with the hot surface of the chimney, they are wrapped in heat-insulating material.

The section of the chimney crossing the attic space is called the riser (9). In its lower part, just at the level of the attic floor, there is another widening - fluff (10).

Note! All three widenings - head, otter and fluff - are made only due to thickening of the wall, while the cross-section of the channel always remains constant. The otter with fluff, as well as other chimney elements installed at the intersections of the roof or ceilings, are called trims.

The thick walls of the fluff protect the wooden floor elements (11) from excessive heat, which can cause them to ignite.

The chimney can be made without fluff. Then, in the area where the ceiling passes, a steel box is mounted around the pipe, which is subsequently filled with a bulk heat insulator - expanded clay, sand or vermiculite. The thickness of this layer should be 100–150 mm. But experienced users do not recommend using this cutting option: the insulating filler falls through the cracks.

The fluff is additionally lined with an effective non-flammable heat insulator (12). Previously, asbestos was used everywhere in this capacity, but after its carcinogenic properties were discovered, they are trying not to use this material. A harmless, but more expensive alternative is basalt cardboard.

The lowest section of the chimney is also called the neck (14). It has a valve (13), through which the draft can be adjusted.

Depending on the construction method, the chimney may be one of the following types:

1. Mounted. The stove itself serves as the basis for this design. To support the impressive weight of the chimney, its walls must be two bricks thick.
2. Root. Such a chimney stands on a separate foundation and is not part of any heat-generating installation. The smoke exhaust pipe of the stove or boiler is connected to it through a horizontal tunnel - a reversible sleeve.
3. Wall. Chimneys of this type are channels in load-bearing walls. In order to save heat, internal walls are usually used, on both sides of which there are heated rooms.

In a vertical brick chimney, draft is formed naturally, that is, due to convection. A prerequisite for the formation of an upward flow is the temperature difference between the ambient air and the exhaust gases: the greater it is, the stronger the draft generated in the pipe. Therefore, for the normal functioning of the chimney, it is very important to take care of its insulation.

Calculation of basic parameters

At the design stage, it is necessary to determine the height of the chimney and the cross-sectional dimensions of the smoke exhaust duct. The task of the calculation is to ensure optimal traction force. It must be sufficient to ensure that the required amount of air enters the firebox and all combustion products are removed in full, and at the same time not too large so that hot gases have time to give up their heat.

Height

The height of the chimney must be selected taking into account the following requirements:

1. The minimum height difference between the grate and the top of the head is 5 m.
2. If the roof is covered with flammable material, for example, bitumen shingles, the chimney head should rise above it by at least 1.5 m.
3. For roofs with non-combustible coating, the minimum distance to the top is 0.5 m.

The ridge of a pitched roof or a flat parapet in windy weather should not create support above the chimney. To do this you need to adhere to the following rules:

• if the pipe is located closer than 1.5 m in relation to the ridge or parapet, then it should rise above this element by at least 0.5 m;
• when removed from the ridge or parapet at a distance of 1.5 to 3 m, the head of the pipe can be at the same height as this element;
• at a distance of more than 3 m, the top of the head can be placed below the ridge, at the height of an inclined line drawn through it with an angle of 10 degrees relative to the horizontal.

If there is a higher building near the house, then the chimney should be erected 0.5 m above its roof.

Section dimensions

If a stove or boiler is connected to the chimney, then the cross-sectional dimensions should be determined depending on the power of the heat generator:

• up to 3.5 kW: the channel is made the size of half a brick - 140x140 mm;
• from 3.5 to 5.2 kW: 140x200 mm;
• from 5.2 to 7 kW: 200x270 mm;
• over 7 kW: in two bricks - 270x270 mm.

The power of factory-made heat generators is indicated in the passport. If the stove or boiler is homemade, you have to determine this parameter yourself. The calculation is carried out according to the formula:

W = Vt * 0.63 * * 0.8 * E / t,

• W - heat generator power, kW;
• Vt - volume of the firebox, m 3;
• 0.63 - average furnace load factor;
• 0.8 - average coefficient showing what part of the fuel burns completely;
• E - calorific value of fuel, kW*h/m3;
• T is the burning time of one fuel load, hours.

Typically, T = 1 hour is taken - approximately this is the time it takes for a portion of fuel to burn during normal combustion.

The calorific value E depends on the type of wood and its moisture content. The average values ​​are:

• for poplar: at a humidity of 12% E - 1856 kWh/cubic meter. m, at a humidity of 25 and 50% - 1448 and 636 kW*h/m3, respectively;
• for spruce: at humidity 12, 25 and 50%, respectively, 2088, 1629 and 715 kW*h/m3;
• for pine: respectively, 2413, 1882 and 826 kW*h/m3;
• for birch: respectively, 3016, 2352 and 1033 kW*h/m3;
• for oak: respectively, 3758, 2932 and 1287 kW*h/m3.

For fireplaces, the calculation is slightly different. Here the cross-sectional area of ​​the chimney depends on the size of the firebox window: F = k * A.

• F - cross-sectional area of ​​the smoke exhaust duct, cm 2;
• K - proportionality coefficient, depending on the height of the chimney and the shape of its cross-section;
• A is the area of ​​the firebox window, cm 2.

The coefficient K is equal to the following values:

• with a chimney height of 5 m: for a round section - 0.112, for a square section - 0.124, for a rectangular section - 0.132;
• 6 m: 0.105, 0.116, 0.123;
• 7 m: 0.1, 0.11, 0.117;
• 8 m: 0.095, 0.105, 0.112;
• 9 m: 0.091, 0.101, 0.106;
• 10 m: 0.087, 0.097, 0.102;
• 11 m: 0.089, 0.094, 0.098.

For intermediate height values, the K coefficient can be determined using a special graph.

They tend to make the actual dimensions of the smoke exhaust duct close to the calculated ones. But they are selected taking into account the standard sizes of bricks, blocks or cylindrical parts.

Materials and tools

A brick chimney is operated under conditions of significant temperature changes, so it should be built from the highest quality bricks. Compliance with this rule will determine how safe the structure will be: if the brick does not crack, it means that poisonous gases and sparks that can cause a fire will not enter the room.

Types of bricks

The pipe is erected from solid ceramic bricks with fire-resistant properties of grades from M150 to M200. Depending on the quality, this material is divided into three grades.

First grade

When making such bricks, the temperature and holding time during firing ideally correspond to the type of clay. You can recognize it by the following signs:

• the blocks are bright red, with a possible yellowish tint;
• the body of the brick has no pores or inclusions visible to the eye;
• all edges are even and smooth, there are no crumbled areas on the edges;
• Tapping with a light hammer or other metal object produces a loud and clear sound.

Second grade

Such a brick is unburned. Here are the signs that characterize it:

• the blocks have a pale orange, slightly saturated color;
• numerous pores are visible on the surface;
• the sound when tapped is dull and short;
• There may be defects on the edges and edges in the form of burrs and crumbled areas.

Brick of the 2nd grade is characterized by low heat capacity, frost resistance and density.

Third grade

• the blocks have a deep dark red color, some are almost brown;
• when tapped, the sound is too loud;
• edges and edges contain defects in the form of chips and burrs;
• the structure is porous.

Such bricks do not have frost resistance, do not retain heat and are too fragile.

The chimney should be built from first grade brick. Second-grade should not be used at all, but third-grade can be used to make foundations for free-standing pipes.

What solution is needed

The quality requirements for mortar are as high as for brick. Under any temperature, weather and mechanical influences, it must ensure the tightness of the masonry throughout its entire service life. Since individual sections of the chimney operate under different conditions, different solutions are used when laying it.

If the pipe being erected is a root pipe, then its first two rows (zone No. 3), located under the floor, should be laid on a cement-sand mortar (3-4 parts of sand for 1 part of cement). To make the mixture more plastic, you can add 0.5 parts of lime to it.

The higher-lying sections of the chimney, up to and including the fluff, have an internal temperature of 355 to 400 degrees, so when constructing them, a clay-sand mortar is used. If the fluff ends under the ceiling (zone No. 8), and the cutting is made of bulk material (zone No. 9), then the use of this mixture also extends to the rows in the cutting.

The riser, otter and neck of the chimney (zone No. 10), which do not get very hot, but are subject to wind loads, should be laid using lime mortar. The same composition can be used when constructing the head (zone No. 11), but a regular cement-sand mixture is also suitable for this area.

The clay for the solution should be medium fat. It should not have a strong odor, as this is a sign of the presence of organic impurities that cause cracks in the solution.

The absence of organic matter is also desirable for sand. This requirement is satisfied by mountain sand, as well as its cheaper replacement from ground brick scrap. The latter can be ceramic or fireclay. Since the chimney is built specifically from ceramic bricks, the same sand should be used.

In addition to the specified materials, you will need special purchased elements - a cleaning door, a valve and a cap. The gaps between the brickwork and the metal products mounted in it are sealed using asbestos cord or basalt cardboard.

Tools

The most common tools will be used:

• Master OK;
• hammer-pick;
• plumb line

You can’t do without a building level.

Preparatory work

If a main chimney is being built, then construction work should begin with the installation of a reinforced concrete foundation. Its minimum height is 30 cm, and the sole must be located below the freezing depth of the soil. The chimney foundation should not have a rigid connection with the foundation of the building, since both objects shrink differently.

Some craftsmen soak the brick before starting work. This makes sense, since when dry, the blocks will actively absorb water from the mortar and the masonry will be fragile. But you need to take into account that masonry made from brick that has been soaked takes quite a long time to dry, so choose a technique in accordance with the time of year and weather conditions - the brick should dry before the first frost.

The sand must be thoroughly cleaned of impurities by sifting through a sieve with a mesh size of 1x1 mm, and then washed. It is better to rub the clay through a sieve after soaking. The lime used must be slaked.

Solutions are prepared according to the following recipe:

1. Clay-sand: mix sand, fireclay and ordinary clay in a ratio of 4:1:1.
2. Limestone: sand, lime and M400 cement are combined in a ratio of 2.5: 1: 0.5.
3. Cement-sand: mix sand and cement grade M400 in a ratio of 3:1 or 4:1.

The clay is soaked for 12–14 hours, stirring from time to time and adding water if necessary. Then sand is added to it. The given recipe is designed for medium-fat clay, but it is advisable to check this parameter in advance in the following way:

1. Take 5 small portions of clay of the same mass.
2. Sand is added to 4 portions in amounts of 10, 25, 75 and 100% of the clay volume, and one is left in its pure form. For obviously oily clay, the amount of sand in portions is 50, 100, 150 and 200%. Each of the test samples should be mixed until homogeneous, and then, by gradually adding water, turn into a solution with the consistency of a thick dough. A properly prepared mixture should not stick to your hands.
3. From each portion, make several balls with a diameter of 4–5 cm and the same number of plates with a thickness of 2 to 3 cm.
4. Next, they are dried for 10–12 days in a room with constant room temperature and without drafts.

The result is determined by considering the solution that satisfies two requirements as suitable for use:

• products made from it do not crack after drying (this happens with high fat content);
• Balls dropped from a height of 1 m do not crumble (this would indicate insufficient fat content).

The tested solution is prepared in sufficient volume (2-3 buckets are required for 100 bricks), and enough water is added so that the mixture slides off the trowel easily.

How to lay out a chimney with your own hands: step-by-step instructions

If the materials and tools are prepared, construction work can begin:

1. Approximately two rows to the ceiling they begin to lay out the fluff. If there are several channels in the chimney, then the bricks separating them should be partially recessed into one of the outer walls.
2. Lay out the first two rows especially carefully. They set the tone for the entire structure, so they must be perfectly even and strictly horizontal. If a mounted pipe is installed, then from the first rows it is built on a clay-sand mortar, which is applied in a layer 8–9 mm thick, and when the block is installed in place, it is compressed to a thickness of 6–7 mm.
3. Following the order, the neck of the chimney is erected. The seams must be tied so that the masonry does not crack into separate layers.
4. From the inside, the seams are rubbed with mortar (so that the inner surface of the chimney is as smooth as possible).
5. The duration of the fluffing is determined taking into account the expected settlement of the structures:

With each row, the wall thickness in the fluff increases by 30–35 mm. To do this, brick plates of different thicknesses are cut. So, for example, in the 1st row of fluff, in addition to whole blocks, the number of which has increased from 5 to 6, longitudinal and transverse halves (2 pieces each) and several quarters are used. Cut bricks must be laid so that the rough cut faces into the masonry and not into the smoke exhaust duct. The row of fluff, which will be flush with the ceiling, must be isolated from wooden elements with strips of asbestos or basalt cardboard. Next, they return to the original dimensions of the chimney - this will be the first row of the riser. At this stage, using a plumb line, you need to determine the projection of the chimney onto the roof and make a hole in it for it. In waterproofing and vapor barrier films, not a hole is made, but a cross-shaped cut. After this, the resulting petals are bent in such a way that the functionality of this element is not impaired. The riser is laid out row by row, trying to make it absolutely vertical (controlled by a plumb line).

Formation of an otter

The riser ends in a row that extends half its height above the bottom edge of the hole in the roof. Those that are at the level of wooden rafters and sheathing must be insulated with asbestos or basalt strips.

The otter starts next. Like fluff, it gradually expands, but unevenly, taking into account the different heights of the edges of the hole in the roof. Next, the dimensions of the chimney return to their original values ​​- the neck of the stove begins.

The last stage is the construction of a two-row head. The first row is made with a widening of 30–40 mm in all directions. The second row follows the usual pattern, with an inclined surface laid out on the ledge of the bottom row using concrete mortar.

An umbrella is attached to the ledge of the head. The clearance between its bottom and the top of the head should be 150–200 mm.

If the roofing material is flammable and a solid fuel heat generator is connected to the chimney, a spark arrester (metal mesh) must be installed on the head.

The gap between the pipe and the roof must be sealed.

The “steps” of the otter are smoothed with mortar so that an inclined surface is formed, after which the entire outer part of the chimney must be treated with a waterproofing compound.

Insulation of a brick chimney

The cheapest way to insulate a chimney is to coat its surface with a solution based on lime and slag. First, a reinforcing mesh is attached to the chimney, then the solution is applied layer by layer, making the mixture thicker each time. The number of layers is from 3 to 5. As a result, the coating has a thickness of 40 mm.

After the plaster dries, cracks may appear on it that need to be covered. Next, the chimney is whitewashed with a solution of chalk or lime.

A more expensive, but more effective insulation option involves the use of basalt wool with a density of 30–50 kg/m3. Since the walls of the chimney are flat, it is best to use this insulation in the form of hard slabs rather than soft panels (mats).

To install basalt wool on the chimney, you need to secure the metal profile frame with dowels. The insulation is placed in the frame, after which it can be fixed with a stretched nylon cord or screwed to the brickwork with special disc dowels with a large diameter head (to prevent the material from being pressed through).

A vapor-proof film is laid on top of the basalt wool (this heat insulator absorbs water well), and then plastered with ordinary cement-sand mortar over a reinforcing mesh or sheathed with tin (can be galvanized).

Installing the sleeve

Lining of the chimney is carried out in the following sequence:

1. In the boiler or furnace connection area, the chimney masonry is dismantled to a height sufficient to install the longest part of the steel liner. This is usually a condensate trap.
2. All elements of the liner (sleeve) are installed sequentially, starting from the top one. As installation progresses, the installed parts move upward, freeing up space for subsequent ones. Each element has hooks on which you can hook a rope passed through the top hole.
3. After installing the liner, the space between it and the walls of the chimney is filled with non-flammable heat insulator.

At the end, the opening in the chimney is bricked again.

Chimney cleaning

A layer of soot settling inside the chimney not only reduces its cross-section, but also increases the likelihood of a fire, since it can ignite. Sometimes it is even specially burned, but this method of cleaning is very dangerous. It is more correct to remove soot using a combination of two methods:

1. Mechanical involves the use of brushes and scrapers on long, extendable holders, as well as weights on a strong cord, which are passed into the chimney from above.
2. Chemical: a special product is burned in the firebox along with regular fuel, for example, “Log-chimney sweeper” (sold in hardware stores). It contains many substances - coal wax, ammonium sulfate, zinc chloride, etc. The gas released when this product burns forms a coating on the walls of the chimney that does not allow soot to subsequently stick to them.

The second method is used as a preventive measure.

Video: laying a brick pipe

At first glance, the chimney appears to be an extremely simple design. However, at every stage of its construction - from the selection of materials to the installation of thermal insulation - a balanced and deliberate approach is required. By following the recommendations of experts, you can build a durable and safe structure that will last for many years.

Homeowners, as a rule, take the organization of heating in their homes very seriously, choose the safest boiler models, and turn to experienced stove makers. However, what is sometimes overlooked is that incorrect chimney installation is often even more dangerous.

The chimney pipe is the most important element of the heating system in a private house, the assembly of which is carried out in accordance with building codes and fire safety requirements. Installation of a chimney carried out without following these rules is fraught with irreversible consequences - a fire or carbon monoxide poisoning in the house. Today’s article will tell you about the types of chimneys, their design and installation methods.

The chimney pipe serves to transfer smoke and combustion products into the atmosphere; it starts from the inlet pipe of the heating device in the house and ends above the roof ridge with a protective umbrella. In private construction, the following types are mainly used:

The material from which the chimney is made can be selected correctly based on three factors: compliance with the material of the heating device, low thermal conductivity and tightness of the connections.

Chimney outlet methods

The main task of a chimney is to remove smoke outside the house, which can be organized in several ways. The choice of pipe insertion location depends on the location of the heating device, free space and type of chimney. The following pipe placement options are used:

External placement is well suited for the bulky design of a brick chimney, and if a metal pipe is routed through the wall, you will have to take care of additional insulation or use special sandwich pipes.

Chimney requirements

The selection of elements is carried out taking into account the requirements of the technical characteristics of the heating device. In order for the system to operate smoothly, the basic principles of chimney design must be observed:

1. A round shape is preferable, since combustion products and dust accumulate in the corners of the pipe. Round chimneys require cleaning less often than rectangular and square ones.
2. The cross-section of the pipe should not be less than the diameter of the heating device pipe. It is calculated that for every kilowatt of power, 8 square meters are required to ensure the proper level of thrust. cm sections. Typically, information about the required size of the chimney is contained in the instructions for the heating device.
3. Each heating device requires the installation of its own chimney. In some cases, you can deviate from this rule, but then the devices must be located at a different height, the distance between the connection points is 1 m or more. And the size of the pipe cross-section should take into account the total power of the heat generators.
4. The total length of the horizontal sections of the chimney cannot exceed 1 m; violation of this rule reduces the draft force.
5. The chimney ends 0.5-1.5 m above the ridge, on a flat roof - 0.5 m above the surface.

The main criterion for selecting pipes is fire safety requirements and compliance with the heat-generating device, appearance, aesthetics and saving space inside the house are secondary.

Installation sequence

Installation of an internal chimney begins with drawing up a diagram and calculating the required number of pipe segments. To assemble correctly, the device is performed in the following order:

Scheme of the chimney outlet through the corrugated roof

After installation is completed, it is necessary to start the heating system, check the draft and tightness of the connections - even a small amount of smoke indicates serious problems, the solution of which is unsafe to postpone.

Installing a chimney in a house is a responsible undertaking, the quality of which determines the comfort and safety of operation of the heating system, so follow the manufacturers’ recommendations and installation technology.

Video instruction