Chimney insulation from a gas boiler calculation. Chimney installation for a gas boiler: materials, requirements and installation steps. Formula for calculating the optimal design

The arrangement of the exit path for carbon monoxide from the boiler must be carried out in accordance with established requirements and standards. There are dimensional and other restrictions for the chimney so that the outflow of smoke from the gas boiler is carried out safely for human health.

Each individual heating system has its own special requirements for organizing a combustion product removal system. For gas heating equipment, the main thing is to design the chimney in such a way as to ensure the best possible draft.

Gas boiler with chimney and air intake pipe

Ill-proper chimney system equipment can lead to the penetration of carbon monoxide into a living space - this, in turn, poses a serious danger to human health and life.

Requirements for the material for the manufacture of chimneys

The following requirements apply to the material used for the manufacture of pipes intended for the removal of flue gases:

resistance to high temperatures;
high anti-corrosion qualities;
chemical inertness.

Exhaust pipe

Inside, on the walls of the smoke exhaust pipes, due to constant temperature changes, condensate constantly forms, which contains a high content of sulfuric acid. Therefore, it is extremely important that the material used to make the chimney does not come into contact with chemical reaction with acids and also has excellent corrosion resistance. When purchasing, you should also separately specify that the thickness of the inner layer is at least 0.05 cm.

Advice. To reduce the amount of condensate released inside the pipe, the chimney should be insulated.

Metal, ceramic or coaxial chimney?

In a private house, chimney pipes for gas-fired boilers can be metal, ceramic or coaxial. The preferred type of flue pipe material that is suitable for use with a particular boiler is usually indicated by the manufacturer in the technical documentation.

Chimney device

The most common option is metal chimney, which can withstand operating temperatures of 800 degrees. Typically, the pipes of such chimney structures are made of stainless steel; ferrous metal coated with zinc can also be used as a manufacturing material.

In general, the standard design consists of several components: the inner layer of the chimney is made of of stainless steel, on top of it there is a layer of heat-resistant basalt wool and a thin iron casing. Among the advantages of metal chimneys are high resistance to mechanical damage, as well as increased reliability, universal presentation appearance.

Ceramic chimney pipe

Ceramics, which can withstand up to 1200 degrees, are in slightly less demand among consumers. The structure also consists of three layers: a ceramic component, a layer of insulation and a hard shell of expanded clay concrete. Chimneys made from this material are distinguished by their simplicity and reliability, ease of installation, as well as high fire safety.

The coaxial chimney is valued for its presentable appearance and fairly high performance characteristics. In general, this type of construction has a somewhat specific shape, due to which it has an important advantage - condensation does not form on its internal walls. This property is very important for gas equipment, therefore, when choosing a suitable material, you should consider purchasing a coaxial chimney.

Diagram: coaxial chimney device

Attention! Brick pipes are suitable for solid fuel, not gas equipment. Therefore, for gas boilers, an old brick chimney must be converted by inserting a liner made of metal, followed by insulation.

Basic standards

Section size and shape

When calculating the cross-sectional area of a chimney pipe, the dimensions of the pipe installed on a particular gas boiler are taken into account - the chimney ultimately must be no smaller in size. Two boilers can be connected to the chimney pipe, but only on the condition that their inputs will be located at different levels and at a distance of 0.5 m relative to each other.

In this case, the cross-sectional area of the pipe is calculated as the total power of both heaters, multiplied by 5.5. For example, provided that the power of one according to the passport is 1 kW, and the other is 1.4, the cross-sectional area of the common pipe will be (1 + 1.4) x 5.5 = 13.2 cm square.

Installation of a chimney system for a gas boiler

The cross-sectional shape can be in the form of a rectangle or a circle. The smoke flow moves in a spiral inside the chimney and, encountering corners, loses its speed, so round form more preferable, allows for high-quality traction.

Pipe location

The chimney must be installed in a vertical position. The permissible deviation is no more than 30 degrees or up to 1 meter in any direction. At the point of connection to the chimney pipe of the gas unit, a vertical section must be installed, and the height of the section must be at least 0.5 m.

Correctly installed chimney for a gas boiler

Ideally, there should be no bends and all kinds of roundings on the chimney pipe at all, but up to 3 such outlets are allowed. It is allowed to slope horizontal pipes exclusively in the direction where the boiler is located, with a slope angle of up to 0.01 degrees.

Number of probes

It is allowed not to install headers if they impede the exit of flue gases. Under each of the probes, which are located on the tip, you cannot place more than 1 pipe, that is, all individual pipes must have their own “fungi”. The headband must have a cone shape.

Rules for the installation of chimney pipes intended for gas units

During the installation process, you must adhere to a number of established rules:

installation is always carried out in the direction from bottom to top;
the structure is attached strictly vertically;
pipes in height should not reach more than 5 m;
the slightest deflections of pipes are excluded;
all joints, transitions and curves must be carefully sealed using heat-resistant sealant;
along the path of smoke movement there should not be more than 3 horizontal transitions more than 1 meter long;
the head should be located above the wind pressure zone.

Chimney outlet options

Another important requirement for a chimney structure is the mandatory fastening of the pipe to the adjacent wall. Ideally even sections of the pipe are fastened in sections of 150 cm, while its individual parts are fixed to each other without exception. To enhance the overall reliability of the structure, all connections of the elements are fastened together with metal clamps.

SNiP requirements

Regardless of the type of construction, all chimneys for gas boilers must be manufactured and installed in accordance with SNiP 2.04.05-91 and DBN V.2.5-20-2001. Strict adherence to all requirements guarantees safe operation heating system. If the standards set out in these documents are violated, problems will arise that will need to be resolved directly with the gas industry.

Proper chimney installation

The main points of the regulatory documents:

good traction must be organized;
the design of the condensate collector must be carefully thought out so that excess moisture does not accumulate on the walls of the chimneys;
It is not allowed to install fungi, deflectors, etc. on the chimney head, since they slow down the process of removing combustion products;
When carrying out installation work, special attention must be paid to the tight fit of all individual structural parts at the connection points;
A mandatory requirement is to maintain complete tightness at the joints and joints.

Conclusion

The installation of chimney pipes is a responsible process. If installation errors are made, the system may fail, causing serious harm to health and even a threat to human life. Also, if the requirements and standards are not met, more frequent cleaning of the pipe will be required, since large quantities of ash will settle on its walls.

Connected gas boiler

Therefore, during the installation process, especially when it comes to a complex chimney system, it is recommended to involve qualified specialists who will draw up a separate project, as well as carry out all the necessary calculations and ensure the uninterrupted functioning of gas equipment.

Connecting a gas boiler: video

Chimney for a gas boiler: photo

Continuing the topic I started, I think I’ll discuss a chimney for a solid fuel boiler in this review. Why him? Because this type of “smoke pipe” will be universal. Buying, for example, sections of sandwiches with good insulation, and by installing a chimney for a TT boiler, you “kill four birds with one stone” at once - it will be suitable for installing a wood-burning, coal, pellet boiler, as well as for installing a steel or cast-iron heating stove.

The same applies to single-wall stainless steel pipes with a wall thickness of 0.8 - 1.0 mm. That is, the chimney can be used not only for heat generator heat generators, but also for some other types of boiler equipment.

Although, as you know, very good is also not good. Some models of gas and diesel boilers do not work quite correctly with old chimneys. The cause of this is the excessively large diameter of the chimney for the solid fuel boiler that was installed before.

So, let's get started.

“Smoke stack” in section or “Where is the diagram, brother?”

This paragraph provides a diagram of a chimney for a solid fuel boiler - it is quite universal and can be used in many installation cases. This option is suitable for installation in any type of house, with any type of wall material - from brick and monolithic concrete to a wooden frame.

A typical chimney diagram for a solid fuel boiler implies the possibility of leading the chimney through the wall to the side and then upward, or through the ceilings vertically upward and then through the roof.

If we talk about the effective removal of flue gases from the furnace, the main factors influencing the efficiency of this process will be:

Chimney height
Chimney diameter
Length of acceleration section
Chimney insulation

These 4 points are important, the rest are optional.

How much to hang in grams, or choose the height and diameter of the chimney

Let's start with the first two points. The height of the chimney is a critical parameter. What does it mean? This means that if your chimney is not high enough, the draft in the boiler firebox will also be insufficient. This can lead not only to poor combustion of fuel, but also to “draught reversal”, when, instead of being discharged outside, flue gases will penetrate indoors.

This is fraught with the release of carbon monoxide into living spaces, which is deadly to humans.

Carbon monoxide has neither color nor odor. Therefore, you can get burned out unnoticeably and die without waking up.

Have I convinced you that there is no need to save on the “extra” meter of pipe?

The required chimney height for a solid fuel boiler or for a heating stove, for each individual model of boiler or stove, as well as for different thermal powers, is required to be specified in the passport. At the same time, sometimes the “minimum” height is written in the passport, and sometimes “just” the height.

The minimum height must be observed, and “just” the height is the lower limit for conducting experiments with the draft of the TT boiler. Does it pull poorly at the minimum height? We add another half meter to a meter of chimney. And so on.

When conducting these experiments, do not forget that in the summer, especially in damp, warm weather, the draft will be worse than in the frosty and dry winter. Therefore, if the chimney of a solid fuel boiler is installed in winter, you must understand that in summer the draft at the set height will be worse than at the time of installation.

The minimum chimney diameter for a solid fuel boiler or stove is also indicated in the passport for the purchased boiler or stove. If you don’t have a passport, then there are now tables for almost any model on the Internet.

You can slightly narrow or widen the cross-section of the chimney by changing the diameter by no more than 5 mm in one direction or the other.

This won't affect traction much. If, for example, you take 120mm pipes instead of 150mm, you can easily get problems with efficient fuel combustion in some models of TT boilers and.

This effect is usually “treated” by lengthening the chimney, however, increasing the height does not always lead to the desired result.

As for an excessive increase in the diameter of the chimney, this risks the fact that the flue gases, without having time to give up heat to the heat exchanger, will quickly leave the boiler furnace. What is called “heat will fly away into the chimney.”

Acceleration section of the chimney

In the case of using an acceleration section, the solid fuel boiler can be connected to the chimney vertically or horizontally. Immediately after the initial short branch pipe or tee there will be at least 1 meter of accelerating vertical pipe. It serves to “launch” traction. Next, you can install horizontal sections and branches, but no more than 0.5 meters in length.

This means that the outgoing flue gases, entering the chimney, already have an extremely low temperature. And if they continue to give off heat through the walls of the pipe into the surrounding rooms or street air, then their movement will slow down more and more. This means that again there will be no normal draft in the chimney.

To prevent this from happening, the chimney pipe for a solid fuel boiler or stove must be insulated. For this purpose, the easiest way is to use ready-made sandwiches, which are double cylinders made of stainless steel, the space between which is filled with basalt insulation or vermiculite.

The better the sandwich is insulated, the less temperature the outgoing flue gases lose, and the better the draft in such a chimney compared to an uninsulated one.

A chimney pipe for a solid fuel boiler, assembled from sandwiches of 1.0 and 0.5 meters, has a number of other advantages, in addition to the main one - improving draft:

Easy to assemble, because easy installation of sections of 0.5 and 1.0 meters is possible
Corrosive
Convenient removal of condensate from the chimney using a drain valve on the tee
Attractive appearance, you can run a pipe made of sandwiches along the facade of the house

In addition to using sandwiches, an insulated chimney for a solid fuel boiler can be obtained in 3 more ways:

Insulate the old chimney with basalt insulation or vermiculite.
Use an old brick pipe from a boiler or furnace, lining it with stainless pipe inserts.
Install an insulated ceramic chimney

The first two methods belong to the budget category. The third method is the most expensive. But it will make you forget about the “chimney issue” for many years.

The design of a chimney made from ceramic sections is clearly visible in the diagram below.

Such a chimney is not afraid of condensation and is not subject to corrosion. In addition, a ceramic pipe is extremely fire resistant and does not burn out like steel.

Selecting the overall dimensions of the chimney

The gas boiler chosen for heating a private house must be available to you, only after that you can select the correct chimney for the gas boiler and calculate its dimensions (see).

The height of the chimney depending on its location relative to the ridge of the house

Attention. If there are extensions above the house or it is planned to build them in the near future, then it is necessary to build a pipe that extends beyond the adjacent building.

Variations with chimney length

By selecting the required diameter and length for the chimney pipe and calculating its usable area, it may turn out that this same area will be less than the internal area of the gas boiler. If you change the pipe diameter to the next one (all pipes are produced in standard diameters), then with the same length you will get an excess chimney area and, accordingly, an excess consumption of material.

What can be done in this situation? Increase the length using a smaller pipe diameter. The table shows the minimum pipe heights. They can be increased, but not decreased.

After calculating the overall dimensions of the chimney pipe and purchasing the necessary building materials, you can begin installation.

Installation of chimneys for gas boilers

Immediately before starting work, you should determine the location of the chimney. There are 2 accommodation options:

When choosing the location of the chimney, you should understand:

location inside a private house will provide the structure with the most “comfortable” operating conditions;
the location behind the walls of a private house requires the presence of insulation to prevent the chimney from freezing; in this case, it is advantageous to use a sandwich pipe (the sandwich pipe has a multi-layer device, in the center of the sandwich pipe there is a layer of insulation).

Of course, the choice of location of the chimney for a gas boiler is yours. Check out the table below to help you make your choice.

Comparative characteristics of a chimney inside and outside a private house.

How to make a chimney for a boiler?

Installing a chimney for a gas boiler in a private house is not very easy.

Let's look at the basic principles of installing a chimney for a gas boiler.

It is necessary to correctly assemble all pipe elements.
In places where the smoke exhaust structure passes through the ceilings or walls of a private house, it is necessary to install special passage elements.
Insulation of all surfaces in contact with flammable materials.

Chimney elements of a floor-standing gas boiler:

adapter from the gas boiler pipe to the chimney pipe;
tee with inspection (at the bottom there is a fitting designed to remove condensate);
main fastenings - bracket and wall clamp;
bends, they are used at a distance of no more 2 m from the beginning of the chimney, otherwise it becomes possible to reduce the boiler draft;
feedthrough pipe;
telescopic pipes;
special tip having a conical shape

Please note that the tip for chimneys that remove “exhaust” gas must have a conical shape. It is strictly forbidden to install ordinary deflectors and umbrellas. It is allowed not to install the tip at all.

Requirements for the chimney of a floor-standing gas boiler:

the slope of some sections of the chimney is allowed no more than 30°;
maximum branch to the side - 1m;
the smoke exhaust duct device should not have ledges or narrowing of the cross section;
the maximum number of elbows that a structure can include is 3, the radius of curvature must be greater than the diameter of the pipe;
at turning points it is necessary to install a hatch for cleaning and eliminating condensation;
one side of a rectangular chimney should not be 2 times larger (smaller) than the other, i.e. the shape should not be elongated;
At the bottom of the chimney, an inspection and drip device is required;
Deflection of chimney elements is not allowed;
the pipe links are placed on top of each other by at least half the diameter of the pipe;
Any gaps between pipe joints are not allowed;
in places where the ceilings (roofs) pass, the pipe should not have joints;
all elements must be very tightly connected to each other;
the slope of the pipe towards the gas boiler must be at least 0.01°;
Roughness in the chimney is not allowed, the inner surface of the chimney elements must be perfectly smooth;
horizontal sections can have a total length 3m in buildings under construction and no more 6 m in built;
Below the connection point of the tee, a so-called “pocket” is required, with a length of at least 25 cm with a hatch (this will provide access to the pipe and the ability to clean it);
distance from the pipe to the structure (walls and ceiling) for flammable materials - 25 cm, non-flammable - 5 cm;
if the pipe passes through unheated areas of the structure, thermal insulation or installation of a sandwich pipe must be provided;
when removing “exhaust” gases from utility appliances, dampers (gates) should be provided;
it is necessary to bring the gate control to an accessible place with fixation of the “open” and “closed” positions;
If the device has a traction stabilizer, then dampers are not needed.

How to properly build a chimney for a gas boiler outside the house?

We attach a passage element to the pipe coming from the floor-standing gas boiler, which will pass through the wall of a private house.
After the opening is ready, we take the chimney out. The sandwich pipe section and the hole in the wall must be insulated.
We attach the tee with revision, put on the plug.
We extend the sandwich pipe by attaching links, attach it to the wall of the house with brackets, in increments of at least 2 m .
Having reached the estimated height of the chimney, we attach a cone-shaped tip.
We reinforce all sandwich pipe joints with clamps, which must be tightened with bolts or wire.
It is advisable to paint the pipe with heat-resistant paint, which will protect the material from corrosion.

If you do not want to use sandwich pipes as a building material for the chimney, then do not forget about the thermal insulation of the structure.

Installation of chimneys for boilers in the house

Let's start with the preparatory work:

We mark the holes for the chimney in the ceilings and roof.
Be sure to check the marked marks several times with the dimensions of the passage pipe. Cut out the required opening for the pipe.

Let's start installing the pipe:

A pipe comes from the boiler. We connect the adapter to it.
Next, we attach the tee and revision (for cleaning the pipes), attach the steel sheet and install the main bracket.
We extend the pipe, if necessary, use the so-called elbows.
When passing through ceilings, we use a special pipe.
We put a galvanized steel sheet on the pipe with a hole slightly larger than the diameter of the pipe. We attach the sheet to the ceiling on both sides.
We reinforce all joints with clamps secured with wire or bolts.
The chimney is secured using wall clamps (each 2 m) and brackets (each 4 m).
We complete the design with a special cone-shaped tip, which will protect the chimney from precipitation and wind blowing.

Insulation of chimney elements

All contacting parts of the chimney and flammable structure must be insulated. To do this, the passage pipe must be covered on all sides with a foil-coated basalt mat with fire-resistant mastic. Mineral wool insulation can be laid around the perimeter of the opening in the ceiling.

Upon completion of installation work, be sure to check the tightness of all seams in the structure. Make an ordinary soap solution and apply it to all chimney seams. If, after connecting a gas boiler to the chimney, you see bubbles, this indicates a leak.

Brick chimney for gas boilers

A chimney can be built not only from steel (certain grades), but also from brick. Or rather, the chimney will be located in brickwork, i.e. the chimney pipe can be metal, asbestos or ceramic. Visually, it will seem that the chimney is made of brick.

Why is it undesirable to build a chimney made of brick?

The fact is that brick is a fairly porous material that does not hold heat well enough. When gas burns, water vapor with various impurities is formed, which, in fact, must be removed from the room, and the construction of a brick chimney will contribute to the formation of condensation.

Chimney for condensing boilers

In general, the chimney of a condensing boiler differs little from the chimney of a conventional boiler, but there are some peculiarities. The chimney of a condensing boiler must be made of acid-resistant materials to protect against corrosion.

It is important that the condensing boiler chimney is sloping to the side heating unit. It is necessary that the condensate flows back, but that precipitation does not enter the unit. Raindrops can damage the condensing boiler.

Chimney for wall-mounted gas boilers

The most optimal building material for wall chimney- double-circuit pipes.

A coaxial chimney consists of 2 pipes, which are inserted one into the other (see). This chimney resembles sandwich-type pipes, but without insulation between the pipes. This ensures the removal of “waste” gas and the influx fresh air through the gap between the pipes.

Installation of such a chimney is quite simple. We attach a flow pipe to the pipe from the boiler and take the pipe outside. The distance from the chimney to the ground must be at least 2 m. When placing the chimney under a window, at least 1 m from the window to the ground level.

Gas boilers without chimneys

Gas boilers without a chimney are the last word in technical progress in this direction. The operation of the system as a whole differs from a conventional gas boiler. Let's not go deeper into this issue. The best thing about this system is that there is no need for a traditional chimney.

In any heating system it is necessary to remove combustion products outside the room. The difference is in the chimneys. In the new system, the chimney can be made of PVC pipes(the temperature of the “exhaust” gases is relatively low) with any number of turns, it no longer has to be strictly vertical.

The boiler operating temperature can be any. The unit runs on both natural and liquefied gas. In case of any problem it turns off automatically.

The information you have gathered will help you when installing a chimney with your own hands. If you want to use the services of professionals, then you will be savvy in the topic of chimneys to gas boilers. This will allow you to independently carry out supervision of the work being carried out.

Installing a chimney pipe, it is very important to calculate the correct chimney diameter, this issue needs to 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.

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.

Approximate and accurate calculation of the chimney diameter.

Accurate calculations are based on a complex mathematical platform. To calculate the chimney diameter, 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°C;
average speed passage of gases along the entire length - 2 m/s;
burning rate of wood (fuel) with one stack B = 10 kg/hour.

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 given value we get the result:

Then we substitute this value into the formula according to which chimney diameter is calculated:

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 it is possible 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. Chimney system diameter in this case there should be larger size blower The square cross-section will be no less than 140*140 mm (this is due to the turbulence created in the brick pipe).

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 chimney diameter, but when installing complex heating systems, an optimally accurate design is important, especially for low-temperature long-burning heating devices.