Do-it-yourself chimney in a bathhouse - selection and installation features

Calculation of a chimney for a wood-burning stove: dimensions, diameter, height above the roof

Calculating a chimney for a wood-burning stove under construction is one of the most important conditions for the normal and high-quality functioning and operation of the system. Therefore, it is very important during construction to adhere to accepted norms and rules as much as possible. Next, we’ll talk about what average parameters need to be taken into account and how to determine them yourself.

Exiting the smoke duct to the roof

Before you remove the pipe in the bathhouse through the roof, you need to take care of two factors necessary for the operation:

• select the location of the output;
• purchase the necessary items.

Place for withdrawal

The pipe outlet through the roof of the bathhouse can be done:

on the ridge of the roof. This location of the chimney is considered the most optimal, since snow and other precipitation does not accumulate in this place and good draft is ensured. However, in practice this is not always feasible;

Chimney located on the ridge

not far from the ridge. The location should be based on the rules shown in the figure:

Rules for the location of the chimney duct on the roof of the bathhouse

Under no circumstances should the chimney be placed in a valley (a depression in the roof formed by several slopes).

Required Items

Installing a pipe into a bathhouse through the roof is impossible without the following elements:

• cutting, similar to the passage through the ceiling;
• insulating material (compliance with safety regulations);
• a special apron that protects the chimney from precipitation.

Cuttings can be used either ready-made or self-made.

Aprons can be:

metal, ensuring a rigid connection of the structure to the roof surface;

Metal apron

flexible, made of rubber or silicone;

Flexible apron

built into a sheet of roofing material.

Sheet with built-in apron

The size of the apron is determined based on the diameter of the chimney pipe.

Instructions for removing the pipe

How to remove a pipe in a bathhouse through the roof? To do this you need:

• make a hole of a suitable size in the selected place on the roof (slightly larger than the outlet pipe);
• Carry out reinforcement work around the hole on the floor beams;
• install a groove from the inside of the roof, as when crossing the ceiling;
• bring out the pipe of the required size;
• install an apron on the outer part of the roof.

Scheme of arranging a passage through the roof

Thus, knowing the fire safety rules and instructions for arranging the main components, you can install a chimney for a bathhouse yourself. To do this, you need to purchase all the materials and basic elements of the system. Before firing the stove for the first time, time is required to dry the sealants used (approximately 1 day) and check the tightness of all joints of the chimney duct.

Why is a chimney calculation required?

In order for your furnace to function properly, it is important that the fume exhaust system is set up properly. Two main parameters play a huge role in this, which we will get to know below. They will determine what draft there will be and how effectively smoke will be removed from the stove. How to correctly calculate a chimney pipe will depend not only on the functioning of the system, but also on the safety of people living in the room. Therefore, pay attention to any subtleties, study the theory, so that later you can easily find out and determine how to independently calculate the chimney.

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Installation of a chimney made of sandwich pipes

Sandwich pipes are ready-made double-walled structures consisting of an inner and outer pipe with insulation between them. To seal the joints of the assembled elements, a special heat-resistant sealant is used. The versatility of sandwich pipes allows you to install a chimney of any design with your own hands.

The procedure for installing an internal chimney with a horizontal exit from the stove is as follows:

1. The necessary materials are purchased and the workplace is prepared. Openings for the passage of the chimney are marked and opened.
2. Using a special clamp and sealant, a stainless steel tee with a tap for draining condensate is installed on the stove chimney. A chimney-convector is inserted into the upper socket of the tee.
3. Then a damper is installed in the convector socket to adjust the chimney draft. A starting adapter is installed in the gate socket (for the transition from a single-wall stove pipe to a sandwich pipe), after which the required number of sandwich pipes is assembled to the required level.
4. All connections are assembled using sealant and secured with clamps. The coupling scheme is as follows: the inner pipe is “through condensate” (the upper pipe enters the socket of the lower one), the outer shell is “through smoke” (the lower one enters the socket of the upper one).
5. To pass through the ceilings, a ceiling-passage assembly is installed on the chimney with expanded clay filled into the gaps. The passage unit performs a dual function: fixing the chimney and preventing the impact of high temperatures on building structures.
6. After leaving the roof, a cap is installed on the last sandwich, and the junction of the pipe to the roof covering is sealed with a special elastic element.

Attention! The joints should not be inside walls, ceilings or roof structures.

Upon completion of the work, it is necessary to test the assembled structure - a test firing of the furnace to ensure the tightness and reliability of all connections.

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What parameters need to be calculated?

To calculate, you need to determine the following parameters:

1. Length. First of all, you need to determine the maximum height of the building, how many meters to the ridge of the roof in the very place where the future pipe is supposed to exit. Because one of the most important characteristics of the future system will depend on the length. Take into account the fact that channels that are too high will simply “eat up” the draft; as a result, it will reach the heat source at a lower speed, which means your stove will burn much worse. In addition, chimneys that are too low in relation to the roof are also “scary”; more about this below.
2. Chimney diameter (section). As for this parameter, it is necessary to take into account not so much the dimensions themselves as the original shape of the pipe itself. Do not forget an important condition: if you want to get a high-quality chimney system that works according to all the rules, then the pipe must be cylindrical. That is, be sure to make the walls round so that soot and soot linger less in the channel. Thus, you push back the moment of cleaning the channels. As for the size (diameter), it must be selected based on the cross-section of the main outlet pipe of the furnace or boiler. It is not recommended to use pipes with a diameter larger or smaller than the pipe. High probability of depressurization.

List of materials for metal structure

Elements of a metal chimney

To understand exactly what materials need to be purchased, you first need to draw up a detailed drawing, which will indicate all the angles and turns of the pipe. In this diagram, indicate the exact angles so that the knees are chosen correctly for you. Pipe sizes are also very important. It needs to be enough for the entire height of the building. Buy a couple of sheets of metal the same diameter as the pipe. They will need to be fixed to the ceiling of the bath room and to the floor of the attic. It is necessary to take care of heat-resistant materials that will be laid on the ceilings and protect the bath structure from the high temperatures of the chimney pipe. The pipe on the roof must be waterproofed

To do this, you can use glue, sealant or a special rubber seal.

When purchasing chimney pipes, pay attention to their internal cross-section. Depending on the power of the furnace, you need to choose the one you need.

For a bathhouse, work with a diameter of 15–20 centimeters is usually used. By installing a pipe with a larger diameter than you need, the oven will lose heat too quickly. And if the pipe has a cross-section that is too small, the draft will be insufficient. The height of the chimney pipe must be at least 500 centimeters. The quality of traction directly depends on this. To ensure that the pipe lasts as long as possible, choose the metal from which it is made, with a thickness of at least 1 millimeter. If you plan to install a heating water tank, consider this too. Indicate its location on the diagram and calculate what you need to purchase to install it.

How to calculate chimney parameters?

As described above, you need to know certain parameters. If the two main parameters are height and cross-section, then there is one more indicator that must be taken into account. These are the characteristics of the heating equipment itself.

There are several forms of calculation, divided into:

• Accurate.
• Approximate.
• Automatic.

By the first, we need to understand that it is necessary to take into account a lot of factors, including gas temperature indicators, separation speed, height and speed at which combustion of a particular fuel will occur. These values ​​must be substituted into a special formula; a detailed calculation will be given at the end of the article.

As for the approximate calculation, the size of the combustion chamber is taken into account. For example, let’s take the classic size of a regular chamber in a furnace or boiler - these are dimensions within the range of 500 by 400 mm. The substitution system is used, that is, 1:10. Then for round channels, the diameter will be 180 - 190 mm.

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The third type of calculation is the use of special calculation calculators. As a rule, they provide more accurate data, but you need to know more initial parameters. Roughly speaking, this is the same first method of counting, but it is performed using a computer.

Determining the height of the chimney

We already know that the performance of the system depends on this parameter. Therefore, keep in mind that according to SNiPs, the average height should be 5 meters, but not more than 7 meters. With a shorter length, natural traction will not be formed in sufficient quantities. When calculating, follow the described rules:

• From the base to the highest point is more than 5 meters.
• Exit to a flat roof is marked by an elevation of the pipe head by 500 mm.
• When erected on a pitched roof, three meters to the ridge, the chimney, when drawing a visual line, should be located at a 10 degree angle. The shorter the distance to the ridge, the correspondingly greater the degree.

Determination of the cross section of the smoke channel

In order not to use complex geometric calculations, we recommend that you pay attention to the recommendations of experts. So, the diameter of the chimney must meet the following criteria:

• If the power does not exceed 3.5 kW, then a diameter of 0.14 cm is sufficient.
• Power up to 5 kW is equal to a diameter of 0.20 cm.
• Power up to 7 kW, equal to a pipe cross-section of 0.27 - 0.30 cm.

If you want to calculate the cross-section more accurately, you can use parameters such as fuel type, combustion rate, thrust speed, height, and speed of passage through the pipe.

How does the diameter of the chimney affect its height?

The diameter of the chimney pipe partly only affects the height. Roughly speaking, you will not be able to expand the cross-section in order, for example, to reduce the length of the channel - these values ​​are not interrelated, as many believe. Therefore, you should not “be tricky” with the diameter, adjusting a certain height, which will be below 5 meters or above 7 meters. The level of traction will be the same throughout the entire length from 5 to 7 meters. But a diameter that is too large can reduce traction and create turbulence, although at first glance this seems absurd.

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Calculation of the optimal traction indicator

In addition to calculating the diameter of the chimney, you also need to know the draft force. To do this, you will need to find Bernoulli's law and substitute the external and internal temperature data, as well as the pressure level. For the final calculation, the total pressure loss in both zones is taken into account. If the indicators are identical, then the traction is in the optimal range.

Example of furnace calculation

As promised, at the end we provide an example of independent calculation. So, you need to calculate the diameter of the chimney for a wood-burning stove using the following formula:

D = 4*Vr/3.14*2 = 0.166 m. The values ​​are selected based on standard sizes and indicators according to the table. Where:

D – Section. Vr is the required volume of air for combustion. 4 is the standard thrust setting.

How to insulate a chimney pipe in a bathhouse

To perform pipe insulation work, you can use the following materials:

• teploizol;
• folgoizol.

Teploizol began to be used recently. It is made of polyethylene foam, which is hidden between several sheets of foil. The thickness of the material is from 2 to 10 mm. The thicker the insulation, the higher the temperature the material can withstand.

Table: dependence of the maximum possible temperature on the thickness of the insulation

The top layer of foil can protect the pipe from severe overheating. Installation of thermal insulation is simple. You just need to wrap it around the chimney, securing it with tape or iron wire.

Another popular material is foil insulation. It consists of layers of foil and heat insulator. The foil will be used as a reflective material, which allows you to save up to 90% of heat in the bath.

The best material for chimney insulation is foil insulation.
This material is environmentally friendly, since large thickness food foil is used in the manufacturing process. The material is resistant to ultraviolet rays and elevated temperatures. Acceptable temperatures are from -65°C to +175°C. It is often used for thermal routes and pipelines.

This material often covers not only the pipe, but also the walls and ceiling of the steam room. The building, which is lined inside with foil insulation, has a thermos design. The heat will not escape, and therefore the bath building will quickly warm up and will not cool for a long time.

Quite often, safe sandwich pipes are used in bathhouses. The design is similar to a pie. The internal part is made of stainless steel, then insulation material is laid, and the external part is made of galvanized steel. The design can perform two functions at once: eliminating the accumulation of soot inside and reducing heating outside.

If red brick was used in the manufacturing process of the stove, then this insulation method will not work. You will need to do the following:

1. The pipe outlet on the ceiling structure and through the roof must be insulated from elevated temperatures using asbestos sheets. To do this, you need to cut a sheet whose dimensions exceed the dimensions of the pipe by about 10–15 cm on all sides. The structure is screwed on with self-tapping screws.
2. The walls of the inside of the pipe should be covered with a sheet of metal. Ordinary iron sheets cannot be used, as they may be subject to corrosion. The dimensions of the sheet should be the same as in the case of asbestos sheet.

It is recommended to build an iron box around the pipe where it passes through the ceiling and pour expanded clay inside. The thickness of the layer is 5–10 cm. It can contain heat and protect wooden parts from ignition.

Based on fire safety requirements, there should be no wooden frame around the chimney pipe within a radius of 25 cm. A more difficult task is to arrange the passage of the chimney between floors. It is important to preserve the tightness of the steam room and prevent heating of the wooden parts of the ceiling structure and internal cladding elements by the hot pipe.

For this purpose, you need to use cutting. The design is necessary to arrange a fire-safe passage of the smoke exhaust through the ceiling and wall, as well as to protect finishing parts from ignition. The cutting can be made from an iron box. The horizontal size is determined taking into account the diameter of the sandwich pipe, but the minimum value is 40 cm. The depth must exceed the thickness of the ceiling by 7 cm.

It is important to consider the following tips for installing the cutting:

1. The junction of the box and the ceiling must be paved with a sheet of asbestos or basalt.
2. The lower part of the groove is fixed with self-tapping screws, but they need to be thermally insulated. To do this, in the place where the fastening element is installed, you should prepare a recess equal to 2 diameters of the self-tapping screw. In this case, the fasteners will not contact the bottom of the box.
3. Next, you need to put a washer and a piece of asbestos on the self-tapping screw.
4. The fastener is screwed into the recess.

After installation, the groove should be filled with thermal insulation material. This is done in the following order:

1. A 20 mm layer of clay is applied to the bottom.
2. The remaining space is filled with expanded clay.

Methods for calculating the diameter of a chimney for a wood-burning stove

The efficiency and performance of the stove depends on the optimal cross-sectional size and height of the chimney. SNiP rules and several calculation options will help you choose the right size for a wood-burning stove in your home.

• Why do you need to know the diameter?
• What should be the diameter of the chimney for a stove?
• Calculation methods
• Exact method + formula
• Swedish calculation method
• What to do if the chimney cross-section is square?
• What should be the height of the chimney pipe for a stove?
• Why is this parameter needed?
• SNiP requirements
• Self-calculation method
• Table “Height of the chimney above the ridge”
• Conclusion

Features of the chimney

Removal of gases through the channel will occur effectively only if the pipe is constructed according to standard dimensions and made of the correct material. These pipe characteristics are selected depending on the type of fuel; the material for the chimney is:

• refractory ceramic bricks;
• asbestos pipes;
• stainless steel;
• sandwich pipes with an inner layer of insulation.

Brick channels are made in the case of a stationary chimney , which ensures the removal of gases when heating with wood and coal. To determine the diameter and internal size, the boiler power and the dimensions of the firebox are taken into account. If the calculation is incorrect, reverse draft results or the useful effect of the furnace is significantly reduced.

For gas boilers, it is effective to use pipes with two walls , between which insulation is laid. The problem with a chimney for a gas fuel boiler is internal condensation, so insulation will help avoid significant temperature differences.

It is allowed to install one chimney for two operating heating units , if the internal size of the chimney, raised to the required height above the roof ridge, allows combustion products to be easily removed from both stoves. The cutting section pipe is about 0.8 m high.

A feature of the functioning of the chimney is that all overall, internal dimensions and height must be made with maximum accuracy. A wide and tall chimney, folded to a large height, with a low power of the heating unit, will reduce the efficiency. Insufficient dimensions will lead to smoke being sucked into the room, creating backdraft, and leaking dangerous carbon monoxide.

The warmth in the house depends on a well-designed heating system. But not a single stove or boiler will be able to cope with the task of supplying heat unless a technically competent chimney is made, raised to the required height above the roof ridge.

Dependence of draft on pipe height

The importance of the chimney in the heating system cannot be overestimated. Attempts to save on an extra meter of pipe will lead to cold walls during the heating season and excessive waste of fuel. The danger of carbon monoxide is that it is invisible and undetectable, but can be fatal.

Thrust occurs when heated smoke and gas with low density, in accordance with the laws of physics, rises upward. The result is a pressure difference at the beginning and end of the channel, that is, draft occurs. To ensure that the process is constantly repeated, cold oxygen is supplied through the blower. The greater the temperature difference, the stronger the thrust will be.

A narrow chimney of great height relative to the ridge will accelerate the smoke masses, thus reducing heat transfer. To maintain the desired temperature in the room, you will have to add fuel in excess of the norm. A wide channel of small height will allow smoke and gases to rotate arbitrarily in the pipe, their movement will slow down, and most likely a reverse flow of gases will result. Most often this happens in autumn or spring, when the temperature difference between outside and inside decreases and smoke, without overcoming resistance, is drawn into the room through the firebox.

Chimney location and height

To correctly select the height of the chimney relative to the roof ridge, you need to take into account the location of nearby structures. For an outdoor home, the draft indicators will be good, since there is constant blowing and pick-up of smoke masses. If we talk about a small building surrounded by high-rise buildings, then the length of the pipe should be increased. The height of the chimney depends on several factors:

• slope of the roof plane;
• location of the channel on the roof plan relative to the ridge;
• the location of surrounding buildings and trees;
• estimated thickness of snow cover in a specific area.

When installing a chimney, you should determine:

• elevation of the pipe relative to the roof ridge;
• the total length of the smoke channel from the stove;
• type and dimensions of the head;
• the height of the chimney relative to ventilation and windows of neighboring buildings.

The norms and rules for the construction of a chimney are prescribed in documents SNiP 41.01.03 and in building regulations under number 7.13130.09.

Why do you need to know the diameter?

Beginners do not understand the importance of the chimney cross-section for a stove and why it is so important to correctly calculate not only the internal size, but also the height of the pipe. When developing an individual project for an autonomous heating system for a residential or industrial premises, the level of traction and performance of the unit depends on the accuracy of the data.

Inexperienced builders can make a pipe with a large or insufficient cross-section. In any such option, the operation of the heating device is disrupted, and you are simply throwing money away. For optimal operation of the home heating system, it is important to carry out an accurate calculation and familiarize yourself with the recommendations of regulatory documents.

Chimney design features

A properly constructed chimney for a bath will remove combustion products, ensure heat preservation and fire safety. It can be of two types - external and internal.

External

External chimneys were invented in America. Their main advantage is the high degree of design safety.

In this option, the pipe is connected to the stove, and the chimney exits through the wall to the street. Disadvantages of this system:

• higher fuel consumption;
• the need for insulation of pipes located on the street.

Interior

Internal chimneys are located vertically, therefore, good draft is ensured. The advantage of this design is the rapid heating of the bath, maintaining heat in the room, as well as low fuel consumption. The disadvantages will be:

1. complexity of installation;
2. poor fire protection of the steam room;
3. difficulties in repair and maintenance;
4. danger of internal smoke.

Often combined chimneys are built - brickwork with a metal pipe mounted inside.

What should be the diameter of the chimney for a stove?

The size of the chimney can be calculated in several ways. The simplest one is to determine the cross-section of the chimney depending on the size of the combustion compartment. Solid fuel consumption is determined by this characteristic, and based on these data, the volume of exhaust gases can be determined.

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If you have an open firebox and the chimney is made of a round steel pipe, these values ​​should be in a ratio of 10 to 1. For example, the dimensions of the combustion chamber are 50/40. Such a stove must be equipped with a chimney with a cross-section of 180 mm.

If we make a pipe from brick, its internal size should exceed the size of the ash pan or ash door by one and a half times. The minimum size of a square cavity for gas removal is 140/140 mm.

Device Features

When determining the appropriate type of sandwich pipe for a chimney and its dimensions, you first need to find out how the structure is constructed and what it consists of.

Structurally, the element consists of:

• inner pipe;
• external pipe;
• heat insulator.

The inner as well as the outer pipe is made of galvanized metal, stainless steel, ordinary steel or copper. As for the thermal insulation layer, it is mainly mineral or basalt wool. They are optimally suited for such purposes and tasks.

There are seals on each side of the pipe. They allow better sealing of joints.

It is also interesting that such a pipe can be assembled with your own hands. But I wouldn't recommend taking the risk if you're a beginner. It is better to buy a finished product, since this design has precise dimensions, performance characteristics, and other advantages.

Calculation methods

Exact method + formula

Calculating a chimney for a stove is not a task for beginners. It is better to entrust such work to professionals. But if you decide to calculate this parameter yourself, you will need knowledge of basic data and several formulas:

1. To determine the volume of exhaust gases, it is important to know the power of the heating unit. For calculations we use the formula:, where:

• B is the combustion rate coefficient of solid fuel. This value is determined based on the data in table No. 10 of GOST 2127;
• V – level of volume of fuel burned. This value is indicated on the tag of the industrial device;
• T – heating level of exhaust gases at the exit point from the chimney. For wood stoves – 1500.

1. The total area of ​​the chimney. It is calculated based on the ratio of gas volumes, this value is designated “Vr”, and the speed of their movement in the pipeline. For a household wood-burning stove, this number is 2 m/sec.
2. The diameter of a round pipe is calculated using the formula – d² = (4 * Vr) / (π * W), where W is the speed of gas movement. It is better to perform all calculations on a calculator and carefully enter all values.

Calculating the optimal amount of thrust

This operation is performed to control the calculations of the optimal height and cross-section of the chimney. This calculation can be carried out using 2 formulas. We will present the basic, but complex formula in this chapter, and we will present the basic, simple formula when performing a trial data calculation:

• C is a constant coefficient equal to 0.034 for wood-burning stoves;
• The letter “a” is the value of atmospheric pressure. The value of natural pressure in the chimney is 4 Pa;
• The height of the chimney is indicated by the letter “h”.
• Т0 – average level of atmospheric temperatures;
• Ti is the amount of heating of the exhaust gases as they exit the pipe.

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Example of calculating the cross-section of a chimney

We take as a basis:

• the potbelly stove runs on solid fuel;
• within 60 minutes, up to 10 kg of hardwood firewood burns in the stove;
• fuel moisture level – up to 25%.

Let's look at the basic formula again:

The calculation is carried out in several stages:

1. We perform the action in brackets – 1+150/273. After calculations we get the number 1.55.
2. We determine the cubic capacity of the exhaust gases - Vr = (10*10*1.55)/3600. After calculations, we obtain a volume equal to 0.043 m 3 /sec.
3. The area of ​​the chimney pipe is (4*0.043)/3.14*2. The calculation gives a value of 0.027 m2.
4. We take the square root of the chimney area and calculate its diameter. It is equal to 165 mm.

Now we determine the amount of thrust using a simple formula:

1. Using the formula for calculating power, we calculate this value - 10 * 3300 * 1.16. this value is equal to 32.28 kW.
2. We calculate the level of heat loss for each meter of pipe. 0.34*0.196=1.73 0.
3. The level of gas heating at the exit from the pipe. 150-(1.73*3)=144.8 0.
4. Atmospheric gas pressure in the chimney. 3*(1.2932-0.8452)=1.34 m/sec.

Swedish calculation method

The size of a chimney for a stove can be done using this method, but the main purpose of the Swedish method is to calculate the chimneys of fireplaces with an open firebox.

In this calculation method, the size of the combustion compartment and the volume of air in it are not used. To determine the correctness of the calculation, use the following graph:

What is important here is the correspondence between the area of ​​the combustion chamber (“F”) and the opening of the chimney (“f”). For example:

• firebox dimensions 770/350 mm. We calculate the area of ​​the compartment - 7.7 * 3.5 = 26.95 cm 2;
• chimney size 260/130 mm, pipe area - 2.6*1.3=3.38 m2;
• We calculate the ratio. (338/2695)*100=12.5%.
• We look at the value 12.5 at the bottom of the table and see that the calculation of length and diameter was made correctly. For our stove it is necessary to build a chimney 5 m high.

Let's look at another example of calculation:

• the firebox is 800/500 mm, its area is 40 cm 2;
• chimney cross-section 200/200 mm, area 4 cm2;
• We calculate the ratio (400/4000)*100=10%.
• Using the table, we determine the length of the chimney. In our case, for a round sandwich pipe it should be 7 m.

Rules for installing a sandwich chimney

Here are the general rules for self-installation:

• The chimney is installed less than 1.5 m from the ridge of a nearby building. In cases where it is higher than the roof level, additional installation clamps must be used.
• The elevation of the smoke exhaust structure above the flat roof must be at least 0.5 m.
• The total length of the gas exhaust system is at least 5 m. If this is not possible, then evacuation pumps are used to remove flue gases.
• The minimum permissible distance to the ceiling covering in a wooden bathhouse is 0.38 m.

The answer to the question of what type of chimney pipe should be for a stove in a bathhouse is a stainless steel set. To select high-quality elements for flue gas removal, check the grade of steel with a chromium content of more than 13%, the thickness of the products (optimally 0.8 mm), and the best welds in terms of tightness and durability - after laser welding. The recommended socket connection system is cold formed. Ferrum products meet all these criteria.

What to do if the chimney cross-section is square?

Cylindrical chimneys, especially after the advent of sandwich pipes, are the most common types of devices. But when building a brick kiln, you have to lay out a square or rectangular shape.

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In such chimneys, turbulence is formed, which prevents the normal passage of exhaust gases and reduces draft. But for wood stoves or fireplaces, rectangular pipes remain the most popular shape. Such devices do not require an increased level of exhaust gas extraction.

The calculation of a chimney for a wood-burning stove with a square or rectangular cross-section is made taking into account the ratio of the dimensions of the pipe to the size of the blower hole on the stove. This proportion is 1/1.5, where 1 is the internal cross-section of the pipeline, and 1.5 is the dimensions of the blower or ash pan.

Chimney classification

After completing the calculation part, you need to decide on the type of sauna chimney. It can be internal or external, each of them has its own advantages and disadvantages.

• The external one is easier to install and secure, and has a much lower fire hazard. However, the heat loss from such a chimney will be very significant.
• The internal chimney transfers all its heat to the room, but its installation is more difficult (you need to go through the ceiling and roof). Its main drawback is the increased fire hazard.

But in principle, all disadvantages are minimized when non-combustible materials and high-quality insulation are used during the installation process.

Materials for chimney pipes

Brick, metal and ceramics are usually used as materials for the manufacture of chimneys.

Comparative characteristics:

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Obviously, a chimney made of sandwich pipes is the most preferable, the only thing for which it is “scold” (except for the price) is its service life of 15 years, which is much lower than that of a brick one.

What should be the height of the chimney pipe for a stove?

Calculation of this parameter allows you to avoid the occurrence of backdraft and other possible troubles. This issue is regulated by the rules of SNiP and other documents.

Why is this parameter needed?

In order to understand the importance of this factor, let's take a closer look at several physical laws and the consequences of incorrectly made chimneys. As heated gases pass through, the temperature drops, but warm air or gases always rise.

At the outlet of the pipe, the temperature drops even more. Exhaust gases located in a pipeline with a reliable layer of thermal insulation have a high temperature and a column of heated smoke, rising upward, increases the draft in the firebox.

Let's analyze the situation - we reduce the internal cross-section of the pipe and increase the height of the pipe above the roof ridge. If you think that the volume of heated gas increases, the cooling time of the smoke increases and the draft increases, this statement is only half true. The traction will be excellent, even with a large surplus. Firewood will burn quickly and the cost of purchasing fuel will increase.

An excessive increase in the height of the chimney can cause an increase in aerodynamic turbulence and a decrease in the draft level. This is fraught with the occurrence of reverse draft and smoke escaping into living spaces.

SNiP requirements

The length of exhaust gas exhaust pipelines is regulated by the requirements of SNiP 2.04.05. the rules require compliance with several basic installation rules:

• The minimum distance from the grate in the firebox to the protective canopy on the roof is 5000 mm. Height above the level of the flat roof covering 500 mm;
• the height of the pipe above the roof slope or ridge must correspond to the recommended one. We will talk about this in a separate chapter;
• if there are buildings on a flat roof, the pipe should be higher. In this case, with a large pipe height, it is secured with braces made of wire or cable;
• if the building is equipped with a ventilation system, their height should not exceed the exhaust gas outlet hood.

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Self-calculation method

How to independently calculate the height of the smoke channel, for this you will need to perform a calculation using the formula:

• “A” – climatic and weather conditions in a given region. For the north, this coefficient is 160. You can find the value in other areas on the Internet;
• “Mi” is the mass of gases passing through the chimney in a certain time. This value can be found in the documentation of your heating device;
• “F” is the time for ash and other waste to settle on the walls of the chimney. For wood stoves the coefficient is 25, for electric units - 1;
• “Spdki”, “Sfi” – level of concentration of substances in the exhaust gas;
• “V” – exhaust gas volume level;
• “T” is the temperature difference between the air coming from the atmosphere and the exhaust gases.

There is no point in giving a trial calculation - the coefficients and other values ​​will not be suitable for your unit, and extracting square roots will require downloading an engineering calculator.

Table “Height of the chimney above the ridge”

The table of the height of the chimney above the roof structure will help you determine the size of the pipes without making complex calculations. First, we will analyze the selection of pipe length for flat roofs.

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Design selection

The first thing you need to decide when choosing a chimney is where to install it. There are few options. It can be entirely indoors and go vertically outside through the roof. Or it can be brought out horizontally through the wall and rise up from the outside.

Each option has both advantages and disadvantages that will affect the choice of chimney location.

Internal chimney

The traditional and more familiar way of installing a chimney is inside the bathhouse, vertically upward from the stove, which ensures maximum draft. Passing the entire distance to the ceiling through the pipe, the hot smoke becomes an additional source of heat, so the bathhouse heats up faster, and less firewood is required.

Bathhouse with internal chimney Source rakentaja.fi

Its main disadvantage is the complexity of installation, since the pipe passes through two structures at once - the ceiling and the roof. And the passage units must not only provide protection for their elements from the hot surface of the chimney, but also be sealed so as not to let precipitation inside.

Pipe passage through the roof and ceiling Source sdelai-lestnicu.ru

Another disadvantage is that the chimney takes up a certain space. This can be critical for small rooms, both by reducing the usable area and by increasing the risk of getting burned from the hot surface of the pipe.

However, an additional advantage of the internal chimney is the ability to install a tank for hot water on it, which will heat up, taking heat from the walls of the pipe. Such a tank is called a “samovar”. It can only be mounted on a chimney for a stainless steel bath; in this case, you don’t have to choose which pipe material is better - metal heats up more than others, and it’s only possible to ensure the tightness of the tank.

Stove with a samovar tank for hot water Source e-stroy.pro

External chimney

A chimney that immediately goes outside from the stove through the wall is not the best solution for latitudes with cold and long winters. A huge amount of heat that could remain in the bathhouse is immediately thrown out into the street. And this leads to additional fuel consumption and increased time for heating the premises.

In addition, when hot gases come into contact with the cold walls of the pipe, condensation forms on them. Soot and other combustion products settle on a wet surface, clogging the passage and gradually narrowing the lumen of the pipe. To prevent this from happening, its outer part must be insulated.

External chimney - view from inside and outside Source vosaduly.ru

But this solution also has significant advantages:

• ease of installation - there is only one pass-through unit, through the wall, and it is easier to make;
• maintaining the usable area of ​​the steam room;
• reducing the risk of smoke and fire inside the bathhouse in the event of damage or depressurization of the chimney;
• availability of all components for inspection and repair.

Combined option

External or internal pipe for a bathhouse - which one to choose will be determined by the size and layout of the heated premises, as well as personal requirements for fire safety, fuel economy, and ease of installation.

If you don’t want to touch the roof, but want to install a samovar tank in the bathhouse, you can use a combined design, where the pipe rises up almost to the ceiling and then goes outside through the wall. But the height of the ceiling must be sufficient for such a maneuver - a fire distance must be left from it to the horizontal part of the pipe.

In a combined design, the pipe goes out to the street at the top of the wall Source demyan-pechi.ru

Note! The fewer turns the chimney has, the better the draft. In terms of this parameter, direct internal chimneys connected to the stove from above win.

Chimney pipe diameter - calculation of the chimney cross-section

We welcome you, readers, to our blog of the online store Atmosphere of Warmth. We continue the series of useful articles on choosing a chimney. In previous articles we talked about the selection of steel grade, as well as the correct chimney height. In this same article, we decided to tell you how to choose the diameter of the chimney, what it affects and what it depends on.

What does the diameter of the chimney affect?

The diameter of the chimney or its cross-section directly affects the throughput of the pipe. If it is insufficient, smoke may appear in the heated room.

To begin with, let us clarify that maximum draft is possible in chimneys with a round cross-section, that is, stainless steel chimneys provide better smoke removal.

Again, a metal chimney has smooth walls, which means it will be more difficult for soot and soot to “catch” than, for example, on a brick surface.

So, once we have decided that the cross-section of the chimney should be round, we can begin to select the optimal diameter or cross-section of the chimney.

How to choose the diameter of the chimney pipe

The initial pipe that connects to the heating device must have a diameter equal to or almost equal to the cross-section of the stove, boiler or fireplace pipe.

There is no point in trying to fit a significantly larger diameter onto a smaller one. Yes, special adapters are produced, but is there any point in overpaying for them if you can install a suitable pipe?

A mono pipe is meant as the initial pipe, since it is irrational to connect the stove directly to the sandwich.

Usually mono pipes are installed within the premises, and sandwiches are installed outside.

So, if you purchased a heating device, then simply look at the passport, or measure the diameter of the pipe yourself. If the device is not available, then this point can be clarified directly in the store.

Or, you can obtain the cross-section of the chimney by calculation.

For gas-fired heating appliances, there must be at least 5 cm of cross-section for each kW of power. For solid fuel units - at least 8 cm, respectively.

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In practice this means the following:

For a building with an area of ​​300 square meters, a power of 30 kW will be required (1 kW per 10 m²). Then the minimum cross-section of the chimney for a gas boiler will be 140 mm (area 150 cm²), for a wood-burning stove - 180 mm (area 240 cm²).

We have more or less decided on the internal diameter of the chimney, but how to choose the cross-section for the sandwich pipe?

What determines the diameter of the outer chimney pipe?

The diameter of the outer pipe depends on the thickness of the thermal insulation installed in the pipe. The greater the thickness, the larger the cross-section of the chimney.

Below in the table we have described what thickness of insulation is recommended depending on the purpose of the chimney

Self-installation of a chimney for a bath

The installation method depends on what material is planned to be used for the production of the chimney. There are some rules that should be taken into account when making a chimney yourself:

1. The device must not be connected to other pipes.
2. The smoke exhaust structure should not have horizontal sections longer than 1 m.
3. During the heating season, the sauna chimney must be cleaned at least 2 times.
4. The structure must extend at least 0.5 m beyond the roof.

Installation of a steel sandwich chimney through the ceiling

The first thing to consider is the sandwich chimney. Manufacturers supply products together with a set of additional parts, which include:

• knee;
• tees;
• clamps;
• plugs;
• ceiling-passage units;
• heads;
• protective screens.

The diagram will allow you to understand the technology of installing a stainless steel chimney.
Step-by-step guide to assembling a steel chimney:

1. First of all, using a plumb line, you need to mark the exit points of the pipe through the roof and ceiling structure. Next, you need to prepare a recess according to the size of the pipe. It is worth remembering that between the sandwich pipe and the wooden ceiling parts you need to leave a distance of approximately 10 cm around the perimeter of the recess.

   
   The dimensions of the hole should be approximately 10 cm larger than the dimensions of the chimney pipe

2. Thermal insulation can be done using mineral wool. It will be necessary to close the place where the pipe passes through the ceiling. There is no need to worry about the cotton wool getting damp, as the elevated temperature dries it out quickly.
3. You will need to take all dimensions and determine the location of installation of the unloading unit. It is recommended to do it in the attic. It will take on the load of the pipe that comes out of the ceiling. In addition, the unloading unit is able to eliminate lateral vibrations.

   
   The unloading unit takes on the load of the pipe coming from the ceiling

4. If the distance between the floor base and the attic is large, then a unloading unit should be installed. If the distance is less than 1.5 m, then auxiliary supports are not required. The unloading unit can be constructed from steel angles and fasteners. The corners must be secured to the rafters. The fixation should be as reliable as possible.
5. You will need to install an initial pipe on the outlet pipe of the stove. It must fit into a large pipe with an interference fit; during the purchase process you need to select the appropriate dimensions.

   
   An initial sandwich pipe must be installed on the outlet pipe of the furnace

6. The narrow pipe should fit into the outlet pipe of the furnace, but it should not cover it. The pipe sections must be inserted into each other. The transition and bend areas should be additionally secured with clamps.

   
   Places of passages and bends of pipes must be fixed with clamps

7. Where the pipe passes through the ceiling structure, a groove must be installed to cover the outlet recess. This will also make the chimney more stable. To the groove you need to weld a pipe of a larger diameter, which will be used as an adapter. This will increase the support area and eliminate deformation in the event of strong loads in the side part. The adapter will allow the chimney to move freely up and down. To eliminate heat loss due to loose parts, it is recommended to use mineral wool. It must be placed under the cutting piece and carefully pulled to the ceiling using nails or self-tapping screws.

   
   To close the outlet hole in the ceiling, you need to install a groove

8. Holes must be prepared in the sheathing and roof covering. Next, you should seal the outlet of the smoke exhaust device. An adapter is required for this. The joints must be coated with sealant. It is recommended to place another sheet on the covering and secure it with self-tapping screws and rubber washers. The remaining cracks are treated with sealant. The pipe outlet should be 55 cm above the roof level.

   
   The vertical position must be controlled by the building level

9. A fungus should be mounted at the top of the chimney.

Video: installation of a chimney from sandwich pipes through the ceiling

Installation of a ceramic chimney through the ceiling

The sequence of actions will be as follows:

1. First of all, you need to prepare the place where the device will be placed. If there are any irregularities on it, they must be eliminated. Installation of chimneys is allowed on a separate base near the heating device or on its upper surface. A special adhesive mixture is used for masonry, since the solution will not be able to provide the necessary strength.

   
   For masonry you need to use a special glue, since the solution will not be able to provide sufficient strength

2. You should prepare metal rods 1 m long and 5–10 mm in diameter. With their help, you will need to additionally secure the structure. This will preserve the integrity of the chimney. Next, you need to make recesses in the ceiling and roof. There is no need to make a reserve in terms of dimensions, since the device will be able to protect wooden parts from elevated temperatures.
3. The next step is to install 2 halves of ceramics. The lock should be lubricated with an adhesive mixture.

   
   The first block must be filled with adhesive mixture

4. Next you need to check the location of the halves. If necessary, they can be trimmed. Iron rods should be inserted into the side recesses. The gaps between the reinforcement and ceramics are filled with glue. There is no need to completely fill the cavity. The glue must be positioned so that it connects the rods and ceramics in 3-4 places.
5. Thermal insulating material should be wound around the ceramic pipe and lightly tightened with iron wire or a clamp. There is no need to tighten it too much, since the heat insulator should not shrink. Pressed mineral wool is mainly used as a heat insulation material.
6. The pipe will need to be installed in the recess of the ceramic, and then its location will be checked. To speed up the process, you can wrap all the pipes with insulation at once. The number of pipes corresponds to the height of the chimney.

   
   You can check the location of the pipe using a building level

7. The next ceramic block is mounted with glue. Another pipe is inserted into the socket of the first one. Excess glue from the inner tube should be wiped off immediately, there should be no drips.

   
   The lock of ceramic parts must be lubricated with glue and excess removed

8. The actions are carried out by analogy; during the process it is important to monitor the location of the chimney.
9. To secure the chimney in the attic, you need to cut the slats according to the dimensions of the recess, install them around the perimeter of the chimney and firmly nail them to the attic.
10. The roof where the chimney exits should be sealed. This is done using additional elements that are sold ready-made.

Where the chimney exits through the roof you will need to install a passage unit

Video: installation instructions for a ceramic chimney

Installing a chimney through the wall

1. The first step is to determine the place where the duct will be located inside the building and the chimney pipe will be installed in the wall. To protect the inner base of the bath walls from overheating, a sheet iron screen should be installed. At the passage point, you need to prepare a hole whose dimensions exceed the diameter of the pipe.

   
   To protect a wooden wall from overheating, you need to install a sheet metal screen

2. The chimney must be connected to the inlet pipe of the stove using an adapter. Next, you should put on a piece of pipe with a damper.
3. The parts must be fastened with iron clamps. The joints are treated with a sealant that is not afraid of high temperatures. The chimney must be brought to the point of passing through the wall. If you need to turn the pipe and lay a horizontal section, you will need to use 45° and 90° bends.
4. In the place where the structure passes through the obstacle, you need to place a fire-resistant box. It is made of iron or asbestos cement. In the free space formed between the walls of the box and the pipe, you need to place a thermal insulator that does not ignite.
5. On the street side, you need to fix a part of the smoke removal system in the form of a tee, in the lower part of which there is a container for condensate.

   
   When installing tees, you need to install brackets for support

6. The pipe is completed with vertical sections until the required height is reached. To fix it, you need to use iron brackets. The distance between elements is at least 1 m.

After the chimney exhaust device has been assembled, you will need to light the stove. If the smoke comes out of the firebox quickly, this means that the work was done correctly.

How to install a chimney from a bathhouse through the ground

To run a pipe through the ground, you need to insulate it. A regular layer of bitumen will not work, as the pipe will be at high temperatures. The sequence of actions will be as follows:

1. You will need to prepare several lined pipes, the diameter of the first should be 5–10 cm less than the diameter of the second. One pipe must be placed inside another. It is recommended to entrust the assembly process to specialist tinsmiths.
2. Pipes can be assembled from several parts. The joints are fastened with clamps. There must be 3 spacers between each clamp, otherwise the chimney structure may collapse when falling asleep.
3. The joints should be treated with heat-resistant sealant.
4. The outer pipe, which is located in the ground, will need to be coated with bitumen.

The instructions may seem simple, but it is recommended to entrust this work to experienced specialists.

Chimney diameter.

When installing a chimney pipe , it is very important to calculate the correct diameter of the chimney ; this issue should be given special attention when designing an autonomous heating system. Often the chimney pipe is selected based on approximate parameters. Many people believe that it would be better to make the cross-sectional diameter of the chimney larger, but this is not at all the case. In order for the heating system to function optimally, it is necessary to accurately calculate the diameter of the chimney.

Tips for cleaning chimneys

Unlike chimneys of heating solid fuel stoves, which are cleaned at the beginning of each heating season, sauna pipes are serviced as needed. Practice shows that if you regularly use a steam room, this procedure must be carried out at least 2 times a year.

To remove soot from the inner surface of the flue, it is convenient to use metal or plastic brushes with a metal weight. A rope tied to them allows you to lower the device from top to bottom, cleaning the channel along its entire length.

A brush with a weight for cleaning smoke ducts allows you to clean chimneys of any length

If it is not possible to get to the upper end of the pipe, then a hatch is installed in its lower part. Through it, cleaning is carried out from the bottom up, using the same brush attached to a long steel cable. Condensate from a system with metal pipes is drained using a ball valve, which is mounted at the lowest point of the moisture trap.

The mechanical method, although the most effective, is associated with quite serious labor costs. The process of removing soot can be made easier by using chemicals that are burned in the stove along with firewood.

Video: how to clean a chimney in a bathhouse

The chimney is a mandatory attribute of a sauna stove, on which the efficiency of its operation depends. Choosing exactly what its design should be is only half the battle. It is equally important not to forget about SNiP and fire safety standards during the design and installation process. Only in this case will the wish “enjoy your steam” sound like a call for a safe and pleasant pastime.

• Author: Victor Kaploukhiy
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Initial parameters for calculating the chimney pipe.

To calculate the chimney, you can use the chimney calculator.

The characteristics of the future chimney are directly influenced by certain parameters, of which the most important are:

1. Type of heating device. The organization of a gas exhaust system is in most cases necessary for solid fuel boilers and furnaces. The volume of the combustion chamber is taken into account, as well as the area of ​​the opening of the chamber for air entering the firebox - the ash pan. Often calculations are made for homemade boilers that run on diesel fuel or gas.

2. The total length of the chimney and its configuration. The most optimal design is considered to be 5 meters long and with a straight line. Additional vortex zones that negatively affect traction are created by each turning angle.

3. Geometry of the chimney section. The ideal option is a cylindrical chimney design. But this shape is very difficult to achieve for brickwork. The rectangular (square) cross-section of the chimney is less efficient, but it will also require less labor.

Safety precautions when installing a chimney

It is imperative to ensure high fire safety of the chimney for the bathhouse

To do this, as mentioned above, pay special attention to the tightness of the connections of individual parts of the pipe, as well as to the cutting when the chimney passes through the ceilings and roof

In places where the pipe will pass through the ceiling, it is necessary to insulate it from wooden elements with heat-resistant material - this can be asbestos, mineral wool, sand or expanded clay.

• To do this, a metal panel with a hole through which the pipe will pass is fixed to the ceiling where the chimney passes.
• A kind of box is installed on the attic side, which should be 10-15 centimeters higher than the attic floor. An insulating material is placed or poured into it, which will protect the wooden floor from the high temperatures of the chimney pipe. The pipe must be at least 25 centimeters from combustible floor materials.

Pipe passage through the ceiling

It is very important to arrange thermal insulation protection not only in the ceiling, but also on the wooden wall of the bathhouse. Basically, bathhouse buildings are built from pine, and its wood is quite resinous and can easily overheat and even burn from the high temperatures of a nearby chimney

Therefore, the wall must be protected using non-combustible material - this can be special drywall, asbestos, masonry, foil-lined mineral wool, or a combination.

It is very important to protect not only the ceiling, but also the walls.

• After passing through the attic, the smoke exhaust duct is discharged through the roof and rises above it by at least one and a half meters.
• Around the chimney, when passing through the roofing, waterproofing is installed, which will protect the roof sheathing from moisture, and therefore from the appearance of mold and destruction.

The passage through the roof needs waterproofing

A special protective mushroom is placed on top of the pipe head and a spark arrester is installed.

Water tank

Sometimes a metal tank for heating water is built into the chimney system of a bathhouse, built from metal sandwich pipes, inside which there is an uninsulated part of the chimney. Tanks can have different volumes - this will primarily depend on the power of the selected furnace.

When choosing this chimney accessory, it is best to pay attention to a stainless steel product that will serve for a long time. Naturally, you need to focus on the diameter of the chimney pipe to which the tank will be attached

It is better to purchase the entire set as a set so that you do not have to disassemble an already assembled structure.

Finished chimney section with water tank

The water tank has pipes onto which sections of the chimney pipes are placed. They must fit tightly together, otherwise the draft will decrease and carbon monoxide may enter the room.

A metal water tank is also built into the structure of a brick chimney. In this case, hot air from the furnace passing next to it heats the water poured into the tank. When building a container, you need to provide a place in the chimney wall where there will be a tap and a pipe with a tap for filling the tank.

Diagram of a sauna chimney

This diagram clearly shows all the above-described sections of the smoke exhaust system of a sauna stove.

Approximate general diagram of a sauna chimney

It is worth noting that a sauna stove with its firebox usually opens into another room - the dressing room. This is provided so that there is no risk of getting burned during washing, and so that the bathhouse attendant has the opportunity to constantly add firewood to the firebox.

The stove itself is located directly in the bathhouse with a metal sheathing, which encloses the hot walls and is 10-15 centimeters away from them. Pebble stones are placed at this distance, which, when heated, give off heat to the room, and if you want to get steam, they are splashed with ordinary water or an infusion of fragrant herbs. In this embodiment, the chimney and the tank installed on it are also located in the bathhouse.

Cast iron stove with fence, metal chimney and water tank

The figure also shows how the chimney should pass through the ceilings and roof and how to ensure complete safety of its operation.

Based on this diagram, you can easily build a chimney yourself if you strictly follow all the norms, rules, sizes and volumes of insulating materials.

Approximate and accurate calculation of the chimney diameter.

Accurate calculations are based on a complex mathematical platform. To calculate the diameter of the chimney , you need to know its main characteristics, as well as the characteristics of the fuel and heating device. For example, you can take the calculation of a standard pipe with a round cross-section without rotating units, connected to a stove and burning wood. The following calculation input parameters are taken:

• gas temperature at the entrance to the pipe t– 150°С;
• the average speed of gas passage along the entire length is 2 m/s;
• burning rate of wood (fuel) with one stack B = 10 kg/hour.

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Following these data, you can proceed directly to the calculations. First you need to find out the volume of exhaust gases, it is determined by the formula:

Where V is the volume of air required to maintain the combustion process at a speed of 10 kg/hour. It is equal to 10 m³/kg.

Substituting this value we get the result:

Then we substitute this value into the formula that calculates the diameter of the chimney :

To make such a calculation, you need to know exactly all the parameters in the future gas exhaust system. This scheme is very rarely used in practice, especially in the case of organizing a household autonomous heating system. determine the diameter of the chimney in other ways.

For example, based on the dimensions of the combustion chamber. Since the amount of fuel burned depends on its size, the volume of incoming gases also depends on it. If there is an open firebox and a chimney with a round cross-section, then the ratio is taken to be 1:10. That is, when the size of the combustion chamber is 50*40 cm, then the optimal chimney diameter will be 18 cm.

When constructing a brick chimney structure, the ratio is 1:1.5. The diameter of the chimney system in this case should be larger than the size of the blower. The square cross-section will be no less than 140*140 mm (this is due to the turbulence created in the brick pipe).

Choosing material for making a chimney

Chimneys are made from a variety of materials, from traditional brick to heat-resistant glass and ceramics. They are chosen based on practicality, financial capabilities, fire safety requirements, appearance and many other factors. For example, when deciding which pipe is best to put on an iron stove in a bathhouse, it is unlikely to be logical to consider a heavy brick chimney. Although this option is also possible. Therefore, it is worth studying in detail all existing types of chimneys, their pros and cons.

Brick

A brick chimney has excellent heat capacity - it remains hot for a long time after the end of the firebox, releasing heat into the surrounding space. At the same time, the outer surface of the pipe does not heat up so much as to cause a fire in the adjacent structures. You can also note the safety for health (when heated, the brick does not emit harmful substances) and the visual attractiveness of such a pipe.

The thickness of the walls and the non-flammability of the material make it possible not to construct a fire protection unit when the chimney passes through the ceilings Source mybuilding.tips

However, today this material is not as popular as it used to be, when the choice of chimneys was small. Brick pipes have many disadvantages compared to them.

• Heavy weight. The brickwork has an impressive mass, so such a chimney requires the construction of a durable concrete base buried in the ground.
• Incompatible with modern metal stoves. The brick pipe cannot be placed on the stove; it is laid out separately and connected to the firebox by an outlet pipe.

An example of connecting a stove to a brick chimney Source izba-brevno.ru
See also: Catalog of companies that specialize in fireplaces, stoves and utilities

• Frequent cleaning required. The rough surface of the internal walls and the rectangular cross-section of the pipe lead to the fact that deposits of wood combustion products quickly build up in it.
• Difficult to install. Carrying out brickwork requires experience to ensure that the structure is smooth, with as smooth walls as possible and well-made seams through which smoke should not leak.

Considering all the advantages of brick chimneys and the problems associated with their installation and operation, such structures are chosen primarily for the installation of brick sauna stoves, which are always placed on a foundation. But even in this case, they are often sleeved, installing steel or asbestos pipes inside the masonry.

Through a pipe with a round cross-section, smoke escapes faster, without turbulence Source blogspot.com

Ceramics

Like brick, ceramic chimneys are not afraid of high temperatures, acids, alkalis, and moisture. But they also have a lot of weight and require a support base. And if you choose which is better, a brick or ceramic pipe for a sauna stove, then preference should be given to the latter - the round cross-section and smooth surface do not allow soot and street dust to settle and accumulate on the walls.

Ceramic pipes for chimneys Source schiedel.com

This is an ideal option for a bathhouse, which is most often rejected for three reasons:

• relatively high cost;
• the need to fill the foundation;
• occupied by a chimney installed on the floor next to the stove, the useful area of ​​the steam room.

The pipes themselves do not weigh so much that they cannot be installed directly on the stove. But they are mounted inside special concrete or ceramic blocks that have a large mass. These blocks protect rather fragile thin-walled ceramics from mechanical damage and serve as a frame for laying thermal insulating shells made of basalt wool around them. This design of the chimney eliminates the appearance of condensation in it.

Depending on the type of external blocks, the ceramic chimney can be made single- or double-channel. This is convenient if you need to combine the smoke exhaust system from two stoves. But such a need usually arises only when arranging large baths with many isolated rooms.

The kit may also include shaped connecting elements and special compounds for assembling and sealing the chimney Source vhdom.ru

Glass

If we talk abstractly about a chimney for a bathhouse - which one is better to choose, so as not to think about the need for repair and cleaning, and not to be afraid of fires and smoke leaks, then the most correct solution would be a pipe made of heat-resistant and impact-resistant glass.

But it will cost a very decent amount, since both the material itself and the installation of a glass smoke duct cost a lot of money. And finding a specialist capable of professionally performing this work in our country is still almost impossible.

Asbestos

This option cannot be recommended for indoor installation on a sauna stove, since asbestos releases toxic substances when heated. Such pipes can be installed during external installation of chimneys, using steel adapters to connect to the firebox and pass through the wall.

But you need to understand that cheap asbestos pipes will not last long, since their porous surface will absorb moisture, which expands when freezing and causes destruction of the material. In addition, soot will quickly accumulate on their walls, and cleaning the channel using mechanical methods can be disastrous for fragile walls.

Inexpensive but unreliable asbestos pipes Source mtv-plus.rf

Swedish method for calculating chimney diameter.

In the examples described above, the height of the gas exhaust system is not taken into account. For it, the ratio of the area of ​​the combustion chamber to the cross-section of the pipe is used, taking into account its height. The pipe value is determined according to the graph:

Where f is the chimney area, and F is the firebox area.

However, this method is more applicable to fireplace systems, since the volume of air for the firebox is not taken into account.

You can choose different methods for calculating the diameter of the chimney , but when installing complex heating systems, an optimally accurate diagram is important, especially for low-temperature long-burning heating devices.

How to clean a chimney

After answering the questions about how to properly install a smoke exhaust structure and what materials are available, we will figure out how to care for the chimney. If your bathhouse or sauna is supplied with firewood, fuel briquettes, coal or other types of solid fuel, you will need to clean the chimney from time to time. There are two effective ways to remove scale from pipes.

1. Mechanical cleaning with a brush is an old and reliable method. It requires certain knowledge, time, strength and special tools. For a brick chimney, it is better to take a steel brush, and for a metal chimney, a plastic one.
2. Cleaning with chemicals. There are two types of substances - for prevention (powdered additive to firewood) and “chimney sweep” logs. It contains a large dose of active substances, which, when burned, remove all accumulated soot.

Material

Bath stove pipes are made from the following materials:

• baked brick (silicate brick is not suitable) - has good heat exchange with the environment, is fireproof, such a chimney requires strong support;
• ceramics - resistant to high temperatures, physical and chemical influences, ceramic blocks are made specifically for chimneys.
• ferrous metal - to protect it from corrosion it is coated with enamel, it can withstand temperatures up to 500°C, but is not suitable for intensively working baths;
• stainless steel - is durable and lightweight, a pipe made from it can be installed on a stove with a wall thickness of half a brick, the best brand is AISI 321 (with an admixture of molybdenum), the material must be purchased from a trusted manufacturer.

Asbestos cement is a too porous material; it easily absorbs condensation, which, when combined with soot, destroys the pipe and it can burst. To avoid this, it must be insulated and lined with brickwork. In the steam room, chimneys with a galvanized outer casing are not used, because This material releases harmful substances when heated.

Wooden parts of the roof and roofing made of flammable materials have a high fire hazard. The pipe is placed from them at a distance of 15 and 30 cm, respectively, and these structural elements are insulated with roofing steel and flexible sheet asbestos.