Documentation / 05.04.2020

How to calculate the parameters of the chimney. Calculation of a chimney: how to calculate the necessary parameters Calculation of a chimney steel pipe of a boiler room

One of the most important requirements for ensuring the safety of operation of solid fuel heating equipment is proper organization removal of combustion products. With the expectation that they timely and completely go outside, without penetrating into the room, and give way to the influx of fresh air necessary for the continuous burning of the fuel bookmark. Violation of these rules leads, at best, to inefficient operation of the furnace or boiler. But much worse is the possibility of poisoning carbon monoxide or the occurrence of a fire hazard.

In this article, we will not consider possible options construction of chimneys - there is a lot of information about this in other publications of our portal. The conversation will focus on the main parameters of the pipe - its cross section, which ensures the timely removal of combustion products at the optimum speed, and the height, which ensures the creation of the necessary natural thrust.

So, the topic of today's conversation is a chimney: calculation of height and section, justifications and convenient online calculators.

Why are solid fuel appliances considered?

It's simple - there are always more problems with them in these matters, when compared with gas ones. Let's explain why:

First of all, gas heaters are almost always factory-made products. That is, they must have a branch pipe of a certain section for connection to the chimney. The cross-sectional area of the channel is also specified in the technical documentation of the model. That is, everything is quite simple - it is not allowed to narrow the channel in any of the sections of the upward chimney.

The temperature of the gas combustion products entering the chimney is disproportionately lower than that of wood or other solid fuels formed during the combustion.
It is also difficult to compare the volumes of gas mixtures formed during the combustion of "blue" and solid fuels. The difference here is very significant!

But solid fuel heaters, stoves or boilers are very often created independently. Or they get "inherited" from the former owners of the house. And here it will never be superfluous to check the parameters of the chimney connected to such a device.

However, what concerns the height of the pipe and checking the draft - probably can be fully attributed to gas heating equipment. The cross section is known, but the rest will not hurt to check.

But let's start with the section.

How to calculate the cross-sectional area of a chimney?

There are several methods for calculating the optimal cross section. For example, from the size of the combustion chamber of the hearth or from the area of the blower window of the furnace. But in this publication, attention will be focused on the methodology, which is based on the assessment of the volume of flue gases formed during the combustion process.

Based on calculations and experiments, specialists have long compiled tables from which you can get information about the specific smoke generation for different types solid fuel. That is, what volume of combustion products is formed during the combustion of, say, one kilogram of firewood, coal, peat, etc.

We will also give such a table (in an abbreviated version). In addition to specific smoke generation, it shows the calorific value of the fuel (the amount of heat released during the combustion of one kilogram) and the approximate temperature of the combustion products at the outlet of the chimney. First of specified characteristics we are not particularly interested in a given moment - it just gives a general idea of \u200b\u200bfuel efficiency. But the temperature, yes, will be needed for calculations.

Fuel type	Specific calorific value of fuel, kcal/kg, averaged	Specific volume of released combustion products from combustion 1 kg, m³	Recommended temperature at the chimney outlet, °С
Firewood with an average level of humidity - 25%	3300	10	150
Peat lumpy (loose), air dried, with an average level of humidity not higher than 30%	3000	10	130
Peat - briquettes	4000	11	130
Brown coal	4700	12	120
Coal	5200	17	110
Anthracite	7000	17	110
Pellets or wood fuel briquettes	4800	9	150

As you can see, the volumes are impressive. Even the types of fuel that give minimal smoke are already about 10 cubic meters for every kilogram burned. This means that simply for reasons of physics and geometry, the section of the chimney channel must be able to constantly divert these considerable volumes to the outside.

From this we “dance” when calculating.

chimney prices

chimney

The volume of combustion products emitted during the combustion of solid fuel for an hour can be determined by the following formula (taking into account the thermal expansion of gases).

Vgh =Vsp × Mtch × (1 + Td/273))

Vgh- the volume of combustion products formed within an hour.

Vsp- specific volume of generated combustion products for the selected type of fuel, m³/kg (from the table).

Mtch- the mass of the fuel bookmark, combustible within one hour. Usually it is found by the ratio of the full fuel load to the time of its complete burnout. For example, 12 kg of firewood is loaded into the oven at once, and they burn out in 3 hours. So, Mtch = 12 / 3 = 4 kg / hour.

Td- gas temperature (℃) at the outlet of the chimney (from the table).

273 - a constant for bringing temperature parameters to the Kelvin scale used in thermodynamic calculations.

Since the unit of time in our system of calculation is a second, it is not difficult to find out the volume obtained per second - the result is simply divided by 3600:

Vgс =Vgh / 3600

To find out the cross-sectional area of the channel, which is guaranteed to pass this volume through itself at a certain speed of movement of gases, it is necessary to find their ratio

sc = Vgc /Fd

sc- square cross section chimney channel, m².

Fd- gas flow rate in the chimney, m/s

A few words about this speed. For heating devices and household-class structures, they usually tend to stop in the range from 1.5 to 2.5 m / s. With such, on the one hand, low speed, there is no significant flow resistance, there are no strong turbulences that slow down the movement of gases. Heat losses are minimized, the temperature of the gases at the outlet of the pipe is reduced to normal values. At the same time, the speed is high enough to reduce the formation of condensate and the settling of ash on the inner walls of the channel.

If a section is found (and this is its minimum value), then using well-known geometric formulas, you can find either the diameter for a round pipe, or the length of the side - with a square section, or choose the lengths of the sides with a rectangular one.

Below is a calculator that will simplify these calculations to the limit. It must indicate the type of fuel, the approximate consumption of its consumption (more precisely, the mass and time of burning through the full load) and the expected flow rate of gases in the chimney. The program will do the rest by itself.

The final result is shown in three views:

Minimum diameter for round section;

Minimum side length for a square section;

The cross-sectional area, according to which, for example, you can choose the dimensions of the sides for a rectangular section.

Calculator for calculating the parameters of the section of the chimney pipe

Specify the requested values and click
"CALCULATE THE DIMENSIONS OF THE SECTION OF THE CHIMNEY"

TYPE OF SOLID FUEL

WEIGHT OF A SINGLE FUEL PACKAGE, kg

DURATION OF FURNACE OPERATION ON A SINGLE LAYOUT, hours

EXPECTED GAS VELOCITY IN THE CHIMNEY, meters per second

Chimney height.

Here we can do without complicated calculations.

Yes, of course, there are rather cumbersome formulas that can be used to calculate the optimal height with great accuracy. chimney. But they become really relevant when designing boiler houses or other industrial installations, where they operate with completely different power levels, volumes of fuel consumed, heights and diameters of pipes. Moreover, these formulas also include an environmental component for the emission of combustion products to a certain height.

There is no point in giving these formulas here. Practice shows, and this is also, by the way, stipulated in building codes, that for any of the theoretically possible solid fuel appliances or structures in a private house, a chimney pipe (with natural draft) with a height of at least five meters will suffice. You can find recommendations to focus on an indicator of six meters.

This refers to the height difference between the outlet of the device (for furnaces it is often considered - from the grate) to the upper edge of the pipe, without taking into account the put on umbrella, weather vane or deflector. This is important for those chimneys that have horizontal or inclined sections. We repeat - not the total length of the pipe used, but only the height difference.

So, the minimum length is clear - five meters. Less is impossible! And more? Of course, it is possible, and sometimes it is even necessary, since additional factors may interfere due to the specifics of the building (it’s commonplace - the height of the house) and the location of the pipe head relative to the roof or neighboring objects.

This is also due to the rules against fire safety, and the fact that the pipe head should not fall into the so-called wind backwater zone. If these rules are neglected, then the chimney will become extremely dependent on the presence, direction and speed of the wind, and in some cases the natural draft through it may completely disappear or change to the opposite ("tip").

These rules are not so complicated, and taking into account them, it is already possible to accurately determine the height of the chimney.

chimney prices

flue pipe

First of all, no matter which roof the chimney passes through, the cut of the pipe cannot be closer than 500 mm from the roof (pitched or flat - it doesn’t matter).
On roofs of a complex configuration, or on a roof adjacent to a wall or other object (say, the edge of the roof of another building, extension, etc.), the wind backwater zone is determined by a line drawn at an angle of 45 degrees. The edge of the chimney must be at least 500 mm higher than this conditional line (in the upper figure - the left fragment) ..
The same rule, by the way, also applies when there is a tall third-party object next to the house - a building or even a tree. The figure below shows how the graphical construction is performed in this case.

On a pitched roof, the height of the pipe section protruding above the roof depends on the distance from the ridge (left fragment of the upper diagram).

The pipe, located at a distance of up to 1500 mm from the ridge, must rise above it by at least 500 mm with its edge.

When removing from 1500 to 3000 mm, the upper edge of the pipe must not be lower than the level of the ridge.

If the distance to the ridge is more than 3000 mm, the minimum allowable location of the pipe cut is determined by the line passing through the top of the ridge, drawn at an angle of -10 degrees from the horizontal.

To reduce the dependence of traction on the wind, special caps, deflectors, and weather vanes are used. In some cases, the use of a spark arrester is also required - this is especially true for solid fuel appliances.

It remains to sit down at the drawing of your house (existing or planned), determine the place of the pipe and then finally stop at some of its heights - from 5 meters or more.

Checking the planned pipe for the amount of natural draft

In fact, we have already determined the main parameters of the chimney - a sufficient section of its channel and height. But for devices with natural draft, it will never be superfluous to check the strength of this very draft. So that it does not happen that the built chimney suddenly refuses to fulfill its main functions.

Thrust is, in fact, the difference in pressure between the hot gases in the pipe and the outside air. It is this difference that stimulates the movement of the gas flow through the chimney channel.

It is believed that for normal operation of a natural draft chimney, this difference should be at least 4 pascals for each meter of pipe height (0.408 mm of water column or 0.03 mm of mercury). That is, for a five-meter pipe (our minimum), the thrust must be at least 20 Pa. This ensures both the normal removal of gases and the necessary air supply for continuous combustion of the fuel.

How to calculate this thrust. Naturally, it largely depends on the densities of gases, which, in turn, are closely related to temperature. This can be seen by looking at the formula with which we will work:

Δ P=Htr ×g ×Ratm × (1 / TV - 1 / Tds) / 287.1

Δ P- natural draft in the pipe, Pa.

Htr- height of the chimney, m.

g- free fall acceleration (9.8 m/s²);

ratm - Atmosphere pressure. A value of 750 mmHg is considered normal. However, the area for which the calculation is carried out may have its own specifics. It must be correctly understood that the sea level is considered to be the norm. And with increasing height, this rate begins to decline. And - quite significantly. So when calculating, you will need to be guided by the norm for your region of residence.

Atmospheric pressure is usually measured in millimeters of mercury. However, for calculation in the SI system, it is required to convert it to pascals. This is not difficult if you know that 1 mm Hg. Art. = 133.3 Pa.

TV- outside air temperature. Moreover, reduced to the Kelvin scale, that is, C ° + 273.

Tds- the average temperature of the gases in the chimney. It is defined as the arithmetic mean of the input and output indicators, followed by reduction to the Kelvin scale.

287,1 - gas air constant. It would be more correct to choose this value for the specific chemical composition of the exhaust gases. But in our case, the error will not be significant, greatly affecting the final result.

A few important notes on inlet and outlet temperatures.

You should always strive for its optimal values. Statistics show that most fires occur with sauna stoves, in which there is practically no heat sink, in short time heat builds up in the steam room, and at the same time the chimney usually heats up to dangerous temperatures. Therefore, it is necessary to be able to control the temperatures in the pipe using available means - gate valves, valves, devices for additional heat recovery (for example, hot water tanks).

In household and heating furnaces this is easier, but control is still needed. In boilers, where the very essence of the work lies in the constant transfer of heat to the circulating coolant, these issues are not so acute.

The 900 ÷ 600 ℃ (inlet and outlet) mode found on some sauna stoves is extremely dangerous in every way and should not even be considered! A reasonable framework (and that is their upper limit) is 600 ÷ 400 degrees for domestic brick and metal stoves. Usually they try to withstand in the range of 400 ÷ 200 ℃. For gas equipment the lower limit can fall below 100 degrees.

If all the initial values for substitution in the formula are known, you can proceed to the calculation. To do this, we again suggest using the capabilities of a special online calculator.

Installing a chimney, it is very important to calculate the correct flue diameter, this issue should be given Special attention when designing an autonomous heating system. Often the chimney is selected based on approximate parameters. Many ordinary people believe that it would be better to make the diameter of the chimney section larger, but this is not at all the case. In order for the heating system to function optimally, an accurate calculation of the diameter of the chimney is required.

Initial parameters calculation of the chimney pipe.

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

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

1. Type of heater. The organization of a gas exhaust system is in most cases necessary for solid fuel boilers and furnaces. The calculation takes into account the volume of the combustion chamber, as well as the area of the opening of the chamber for air entry into the furnace - the ash pan. Often the calculation is also made for home-made 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 swirl zones that negatively affect traction are created by each turning angle.

3. The geometry of the chimney section. The ideal option is a cylindrical chimney design. But this form is very difficult to achieve for brickwork. A rectangular (square) section of the chimney is less effective, but it will also require less labor.

Approximate and accurate calculation of the diameter of the chimney.

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

gas temperature at the entrance to the pipe t- 150 ° C;
the average speed of passage of gases along the entire length - 2 m/s;
firewood (fuel) burning rate at one bookmark B= 10 kg/hour.

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

Where V is the volume of air required to maintain the combustion process at a rate of 10 kg/h. It equals - 10 m³ / kg.

Substituting this 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 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 an open firebox and a chimney with a circular cross section, then the ratio is 1:10. That is, when the size of the combustion chamber is 50 * 40 cm, then the optimal diameter of the chimney will be 18 cm.

When erecting a brick chimney structure, the ratio is 1: 1.5. Chimney system diameter in this case should be over size blew. The square section will be at least 140 * 140 mm (this is due to the turbulences created in the brick pipe).

Swedish method for calculating the diameter of a chimney.

In the examples described above, the height of the flue system is not taken into account. For it, the ratio of the area of \u200b\u200bthe combustion chamber to the cross section of the pipe is used, taking into account its height. The value of the pipe is determined according to the schedule:

Where f is the area of the chimney and F is the area of the furnace.

However, this method is more applicable to fireplace systems, since the volume of air for the furnace 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 circuit is important, especially for low-temperature long-burning heaters.

Warning: Use of undefined constant WPLANG - assumed "WPLANG" (this will throw an Error in a future version of PHP) in /var/www/krysha-expert.php on line 2580

Warning: count(): Parameter must be an array or an object that implements Countable in /var/www/krysha-expert.php on line 1802

A lot of attention is paid to the chimney channel in the manufacture of a fireplace or stove, since this element determines how efficiently the entire system will function. In this case, one of the main tasks is to perform calculations and its cross section. These parameters determine the conditions for optimal traction depending on the type of heater and other parameters. Today we will talk about how such calculations are performed. At the same time, we do not urge you to perform them on your own, because without practice no theory can guarantee a high-quality result - however, new knowledge will not harm anyone.

There are several reasons why we make chimney height calculations.

Prices for sandwich chimneys

sandwich chimney

How to calculate the height of the pipe yourself

Next, a self-calculation technique will be given - it is focused on SNiP 41-01-2003 "Heating, ventilation and air conditioning". According to this document, we have the following information:

the minimum height of the chimney, which is considered from the head to the grate, is 5 m;
the optimal height should be 6 m.

However, these data absolutely do not say anything about which parameter to choose in a particular case, for a particular equipment. Therefore, experts use the following formula.

Focusing on the presented formula, we derive the main parameters that are necessary for accurate calculations.

BUT– meteorological conditions of the surrounding area. This refers to some coefficient that has already been calculated by professionals and presented in descriptive documents. For example, for northern regions, the value of this parameter is set to 160.
Mi is the mass of substances passing through in a given unit of time. This parameter can be found in the documentation supplied with the heater.
F- the settling rate of particles that are formed during the combustion of fuel. This indicator can be found in the regulations for the type of fuel used. Let's take wood and an electric heater as an example. In the first case, a value of 25 units is calculated, and in the second - 1.
(Spdki and Sfi) is the concentration of different substances in the gas to be removed. Both indicators are also taken from the instructions supplied with the heating equipment.
V is the volume of the discharged gas.
T- the temperature difference between the incoming air and the gas at the outlet of the pipe.

The height of the chimney above the roof is also a very important parameter. It is determined based on the shape of the roof - all data is also taken from the above SNiP.

If the roof of the building is flat, then the height of the pipe is determined as follows.

Table. The height of the pipe for a flat roof.

If your roof is pitched, then the height of the chimney will be affected by its location relative to the roof ridge - this means remoteness (the distance between them).

Table. The height of the pipe for a pitched roof.

Also, the height of the chimney above the ridge can be affected by third-party factors, such as buildings located in the immediate vicinity and tall trees. The presence of such interference forms a zone of wind backwater. In this zone, it is almost impossible to equip good traction, which will be enough for the normal operation of the heater. To get out of this wind zone, it is necessary to increase the height of the chimney by at least 50 cm.

A similar situation will occur if heating equipment is located in a low utility room attached to the house or located in close proximity. Both options are shown in the diagram above.

In order to install the chimney correctly, it is necessary to carry out a series of design work, which includes both the calculation of the chimney and the choice of material for its manufacture. And if for industrial-scale work it would be best to attract professionals, then in private construction you can limit yourself to it. Below we will consider how to calculate the chimney.

Types of chimneys

The purpose of the chimney is to remove combustion products and smoke from the stove or any other heating device outside the room. The draft in any household chimney is formed naturally and does not involve the use of any additional devices.

Modern chimneys can be made:

From brick. Since such a structure has a significant weight, it is necessary to build a solid foundation for it.

Advice! Experts advise adding lime to the composition of the mortar used for brickwork, which will avoid the formation of condensate, which has a detrimental effect on the walls of the building.

From sandwich pipes, which are made of two layers of metal with a heater laid between them. The most commonly used material for the manufacture of such pipes is stainless steel. In most cases, basalt acts as a heater.
From polymer materials. Such pipes should not be exposed to excessively high temperatures, therefore such chimneys can be used for gas water heaters and small boiler rooms. Wherein, polymer pipes very durable, easy to install and low cost.
From ceramics. Such pipes are characterized by high strength, but they cost a lot. Therefore, they are most often used for arranging industrial-type chimneys. Due to their significant weight, such structures, like brick ones, require laying the foundation.

Important! In some situations, combinations of materials intended for the manufacture of chimneys are possible. For example, a polymer or metal chimney can be lined with bricks.

How is a chimney calculated

In order to calculate the dimensions of the chimneys, it is necessary to navigate in the parameters of the heater. The main dimensions of chimneys are the cross-sectional diameter and height. This data is in the accompanying documentation of the equipment.

How to calculate height

The performance of heating devices directly depends on this parameter, therefore, calculating the height of the chimney is very important. According to the SNiP documentation, the minimum height of the chimney is 5 meters. If the pipe is less than this value, then the necessary natural draft will not occur in it. However, an overly high chimney is also bad, because in this case, the smoke will slowly pass through the system and cool down to reduce the draft.

A serious calculation of chimneys is used in industrial construction. It uses a very complex system of calculations. In private construction, the requirements are usually much less, and the calculation of the height of the chimney involves following the following rules:

From the base to the highest point, the length must exceed 5 meters.
When exiting to flat roof, the chimney must rise above it by at least 50 cm.
If the chimney is erected on a pitched roof with a distance of more than three meters from the roof ridge, then its height is calculated as follows: the line connecting the roof ridge to the chimney and the horizontal line of the roof ridge must be located at an angle of 10 degrees to each other.

The method of aerodynamic calculation of chimneys was developed to determine the resistance and selection of chimneys. A good aerodynamic calculation should take into account possible pressure drops in sections of the gas-air paths, taking into account also the resistances that occur in a certain section.

How is the section of the chimney calculated

In order to calculate the draft of a chimney, it is necessary to first determine its diameter. In order not to carry out complex calculations, you can use the following recommendations of experts:

If the power of the heating equipment does not exceed 3.5 kW, then a chimney with dimensions of 0.14 by 0.14 meters will be enough for you.
If the heating boiler has a power in the range of 4-5 kW, then in this case the optimal dimensions of the chimney will be 0.14 by 0.2 meters.
When using powerful equipment with indicators in the range of 5-7 kW, the cross section of the chimney should be at least 0.14 by 0.27 meters.

Advice! If you know the power of the heater used, then you can safely use the recommendations of the specialists given above. If the power is unknown, then appropriate calculations will have to be carried out to determine the optimal cross section.

The amount of fuel burned in the appliance per hour. Most often, this parameter can be read in the characteristics of the equipment.
Indices of gas temperature at the inlet to the chimney. This parameter can also be found in the hardware specifications. Most often it fluctuates between 150-200 degrees Celsius.

Chimney height.
The speed of gas passing through the pipe.

Note: Default this indicator is 2 m/s.

Indicators of natural traction. Usually this parameter is taken as 4 Pa per meter of chimney length.

The main parameter in calculating the pipe section is the amount of fuel burned. When calculating the diameter of the chimney, you should use the following formula: F \u003d (π * d²) / 4. Thus, to find out the diameter, we derive a new one based on this formula: d²=4*F/π. Using it, you will already be able to determine the pipe section required for your heating equipment.

Conclusion

To ensure correct operation heating system, it is necessary to make a competent calculation of the parameters of the chimney. Only in this case will an effective natural thrust be created. And if complex calculations are usually carried out in an industrial environment, then every home master will be able to independently determine the parameters of a domestic chimney.

The smoke exhaust pipe can be made from various materials:

Brick .
Become .
Asbestos.
Ceramics.

Each of these materials has a different thermal conductivity. The flue gases in the chimney are cooled differently, which affects the draft. This will be taken into account when calculating the height and diameter of the chimney.

The shape of the cross section of the chimney also affects the draft. It can be round, square or rectangular. The most convenient is the round shape.

This indicator depends on design features houses and heights of adjoining houses or trees. There are 3 options:

If the chimney is located no further than 1.5 m from roof ridge, then its height should be 50 cm more than the entire height of the house. At a distance of 10 m from the bottom of the house to its top, the height of the chimney used is Ht = 10 0.5 = 10.5 m.
If the chimney is located at a distance of 1.5-3 m from the roof ridge, then its height can be equal to the height of the house.
If the distance from the ridge is more than 3 m, then you need to use the formula Ht \u003d P - D * 0.1763:

where P is the height of the house;
D is the nearest distance from the chimney to a line that descends from the ridge of the roof down the house (should be perpendicular to the horizon);
0.1763 is a numerical expression for tg(10°).

According to this formula, Ht \u003d 10 - 3 * 0.1763 \u003d 9.47 m.

These three options are possible if there is no tall house or tree nearby. Otherwise, the chimney with a height of 10.5 m may fall into the zone of wind backwater. This means that the traction will be bad. In this case, you need to increase the chimney. To determine the size of the extension, you need to find the highest point of the adjacent house and draw a conditional line from it so that it forms an angle of 45 ° with the ground. The top of the chimney must be above this line, since all the space below it is a zone of wind backwater.

Many manufacturers of solid fuel boilers sell plates in which the dimensions of the chimney and the amount of required draft correspond to a certain power.

m is the mass flow rate of combustion products per hour;
w is the speed of carbon monoxide movement.

S \u003d 0.00556 / (0.6881 * 2) \u003d 0.00404 m² \u003d 40.4 cm².

The diameter of the round pipe will be

where r is a factor that depends on the type of fuel. Its meanings are:

0.045 for firewood;
0.03 for coal.

Structurally, any chimney of a boiler room consists of a foundation, a base and a shaft. The barrel is protected from the inside by a lining, for which a heat-resistant brick is used.

An important point that must be noted immediately is that sanitary norms and rules provide for a direct relationship between the height of the chimney and fuel consumption. In addition, the degree of ash release from the fuel and the amount of sulfur released must also be taken into account.

The installation of boiler pipes must be carried out in accordance with certain standards:

Structures made of brick should have a height of 30 to 70 m with a diameter ranging from 0.6 m to 8 m;
The height of reinforced concrete chimneys can reach 300 m, and the diameter - 10 m;
Steel chimneys of boiler rooms, made of sheet steel with a thickness of 3 to 15 mm, cannot exceed 40 m in height, and 0.4 to 1 m in diameter.

For metal structures, there is an additional rule: if the consumption of multi-ash fuel does not exceed 5 tons per day, then the height of the boiler room pipe may be less than 30 m. Failure to comply with this rule will fundamentally reduce the life of the chimney.

The operability of the system directly depends on how the design of the chimneys of boiler rooms was carried out, which includes the following actions:

Construction analysis;
Aerodynamic calculation of the pipe and gas overpass located in the boiler room;
Selection optimal sizes pipes necessary for its operation;
Calculation of the speed of movement of gases in the building and comparison of the results obtained with the standards;
Calculation of natural draft in the chimney;
Carrying out calculations that determine the strength and durability of the structure;
Calculation of thermal characteristics;
Choice of type and method of fixing the pipe;
Display of the future design on the drawing;
Drawing up a budget.

Installation of boiler pipes must be carried out in strict accordance with the requirements of regulatory documents:

Construction height - OND No. 86;
The degree of wind loads - SNiP No. 2.01.07-85;
Strength characteristics - SNiP No. 2-23-81;
Foundation indicators - SNiP No. 2.03.01-84 and No. 2.02.01-83;
When arranging pipes for gas boilers, SNiP No. 2-35-76 is used;
For electric boiler equipment, you must follow SNiP No. 11-01-03;
When planning the creation of a concrete chimney, it is necessary to build on the requirement of SNiP No. 2.03.01-84;
If the chimney is made of steel, the design must comply with the requirements of SP No. 53-101-98 and GOST 23118-99.

Conclusion

The installation of a boiler room chimney must be accompanied by a very careful and thoughtful approach to work. If all the stages of creating a chimney were performed correctly, then the assembled structure will be able to work out the entire service life without the slightest complaint.

Chimneys are designed to remove smoke and combustion products harmful to humans from a stove or other heating device outside the premises. In any chimney, the draft of the chimney formed during the filling of the latter with gases must be produced naturally, that is, without the use of additional devices.

Currently, chimneys are manufactured:

from brick. For such a chimney, a solid foundation is additionally constructed. It is desirable to add lime to the composition of the connecting mixture used for laying bricks. This will avoid excessive accumulation of condensate that can destroy the walls of the product;

Brick chimney is very popular

from sandwich pipes made from two layers of metal, between which a heater is laid. In most cases, stainless steel is used for the manufacture of sandwich pipes, and basalt is used as a heater;

Sandwich pipes have a layer of insulation inside

from ceramics. Such chimneys are characterized by high strength, but also high cost. Therefore, they are used for the arrangement of industrial chimneys. Due to the large weight, a ceramic chimney, like a brick chimney, requires the manufacture of an additional foundation;

Ceramic chimneys are quite expensive

from a polymer. Such a chimney cannot be exposed to too high temperatures, therefore it can be used to drain harmful substances from gas water heaters and small boiler rooms. The polymer chimney is characterized by high strength at low cost and ease of installation.

Polymer product is easier to install

In some cases, materials for the manufacture of chimneys can be combined. For example, a polymer chimney is lined with bricks.

Combined polymer and brick chimney

The choice of material for the manufacture of the chimney depends on the proposed heater.

Calculating the height of the chimney of a boiler room and its other parameters is impossible without taking into account the features of its design, which is composed of:

foundation and support;
gas outlet;
thermal insulation;
anti-corrosion protection;
device introducing gas ducts.

For the device of the chimney, brick, ceramic, galvanized or stainless pipes are used

The flue gas, having cooled down to 60º C in a scrubber, is cleaned in absorbers and released into the atmosphere.

For the construction of chimneys can be used:

brick. The brick construction, installed by a professional stove-maker, practically does not accumulate soot. It has sufficient fire safety, mechanical strength and heat capacity. Due to the destruction of bricks by reactions that occur when sulfur oxides deposited on the walls come into contact with water, the use of brick structures has sharply decreased;
steel. Allows you to simulate a pipe configuration. Will last about ten years, provided that fuel with a low sulfur content is used;
ceramics. Resistant to condensate, fire resistant. But the design, burdened with metal rods, is characterized by excessive massiveness, which makes installation difficult.;
polymers. They are used for installation on geysers and in a boiler room with a temperature of not more than 250º C.

Depending on the features load-bearing structure chimneys can be:

self-supporting, made of sandwich pipes. They are easily mounted on roofs with fastening inside the building and, if necessary, transported, but they have significant limitations in use - in terms of temperature (350º C), snow and wind load, and the level of chemical aggressiveness of combustion products;
columnar. It is possible to install a multi-barrel steel structure with a diameter of up to three meters when connected to several boilers;
(near) facade. The design is considered the most economical, since it does not require a powerful foundation and the use of load-bearing elements, and the use of modules ensures ease of replacement;
farm. They are used, as a rule, in areas with increased seismic activity;
mast. The use of steel guys gives additional stability to the support tower of three to four masts with attached chimneys.

High pipes are subject to wind load, so you need to take care of additional fastening

The smoke channel can be both located on heating equipment, and stand separately, adjacent to the boiler or furnace. The pipe should be 50 cm higher than the height of the roof. The size of the chimney in cross section is calculated relative to the power of the boiler house and the features of its design.

The main structural elements of the pipe are:

gas exhaust shaft;
thermal insulation;
anti-corrosion protection;
foundation and support;
design for the introduction of gas ducts.

Chimney collective correct connection

Not susceptible to high temperatures when heated.
It is not afraid of moisture formed during the settling of condensate.
Withstands aggressive media (e.g. sulfuric acid).
Creates good traction.

The optimal shape of the home boiler channel is cylindrical, with perfectly smooth walls so that soot does not linger on them: this protects the chimney from constant cleaning. In rectangular brick pipes ah local turbulence creates conditions for clogging, and requires cleaning.

Attention! If the installation of the chimney is carried out independently, it is worth evaluating the problems of transporting the kit and the level of complexity of its installation. Beginner home master you need to discuss the features of your device with a professional. Suppliers of heating equipment can also consult.

The requirements for the chimneys of a home boiler house are regulated by building codes:

The sectional area of the pipe is equal to the area of the boiler nozzle or exceeds it.
For metal chimneys, high-quality alloy steel with high anti-corrosion properties is used, with a thickness of 1 mm; at the base of the channels, special pockets are made more than 250 mm deep for convenient soot removal.
When manufacturing a chimney, it must be remembered that it can have no more than 3 turns, the radius of curvature of which does not exceed the diameter of the pipe.

Compliance with these standards allows you to create good draft in the chimney.

For everybody thermal device it is better to prepare your chimney channel. Chimneys are assembled vertically, without ledges. They allow two deviations from the vertical at an angle of up to 30 degrees, a horizontal connection is allowed within a meter, and the height from the heat generating device to the pipe mouth is from 5 m - to ensure rarefaction of gases and create thrust.

For the correct assembly of the chimney system in the house, some general rules must be considered:

The elements of the modular system are installed from the furnace, from the bottom up.
The options for placing and connecting chimneys are different, it all depends on the conditions of the room. When the house is built, it is convenient to place the chimney outside: it is led out from the stove or fireplace through the wall, an insulator is laid, a condensate collector is installed and the pipe rises on the brackets.
You can install a chimney both during the construction of the house and during operation. The place in the house must be chosen so as not to violate the integrity of the structure of the house: so that moisture does not get in, coordinate it according to the truss system.
If you mount ceramic and brick chimneys in a habitable house, you will have to dismantle the floors, make foundations, preparatory work is expensive and not always possible.
The inner pipe of the chimney system must be inserted into the previous module, and the outer circuit module into the previous one. This makes it possible to protect the basalt insulation from condensation on it.
One pipe must enter the other by at least half of its diameter (according to the markup).
Pipes with branches, tees are connected with clamps.
The connection point should not fall into the overlap layer.
For tees, support brackets are installed.
If a condensate collector is not installed on the tee, all water enters the system.
Every 2m of the chimney is fixed to the wall with a mount.
When attaching the chimney to the wall, you need to make sure that there are no deflections.
No contact allowed smoke channel With engineering communications(gas, electricity).
If the pipe runs close to the walls, thermal insulation is needed.
In the area where ceilings and roofs pass, it is necessary to retreat 150 mm for insulated pipes and 300 mm for pipes without insulation. Fire safety requirements during installation should always come first.
It is impossible to lay horizontal fragments of the chimney more than 1 m in length.
Joints should not fall into floors or layers of roofing cake.

When mounting a steel chimney, it is necessary to take into account the possibility of thermal deformation of the chimney system. For this purpose, a flexible adapter is installed. If there is no such element in the equipment kit, you can not fix the pipe rigidly on the bracket, but make a margin of 10-15 mm, otherwise there is a risk of displacement of the chimney when heated.

If the roof is made of flammable materials, a spark arrester is installed on the pipe, which is made of metal mesh, with cells up to 5X5 mm. The height of the pipe is determined by the distance from the pipe to the ridge: if it does not exceed 1.5 m, the pipe always rises above the ridge at least half a meter.

Speaking of an open hearth, the generally accepted ratio of the chimney section and the size of the fireplace insert opening (width / height) is 1:10. In this case, the shape of the section should be round - this is best option. In designs with square or rectangular section swirls occur in right angles, preventing maximum smoke removal and leading to the formation of soot.

In the case of installing a furnace, the diameter of the pipe must not be less than the diameter of the blower. The minimum cross section is 100 mm. When the heat transfer is less than 3000 kcal / h, the cross section according to the rules is - 140 × 140 mm, otherwise - 140 × 270 mm.

The smoke shaft must be vertical, without narrowing. No more than two deviations from the vertical at an angle of not more than 30 ° are allowed, with a distance of not more than 1 meter. In some cases, the deviation angle of the channel from the vertical is up to 45 °, and the offset is up to 1.7 meters.

Problems with condensate do not have modular chimneys. These are structures assembled from individual elements. Used for their manufacture various materials: carbon and polished high alloy stainless steel, aluminum alloy and ceramic. Such devices can be mounted inside existing brick pipes during their reconstruction or be independent systems operating inside or outside the building.

There are many additional components that facilitate the installation of a gas duct structure.

There is a wide variety on sale:

stretch marks, clamps and brackets;
support platforms and protective aprons;
head, plugs and weather vane caps;
roof seals;
decorative overlays of passage nodes;
compensators necessary to regulate the change in the linear dimensions of sandwich structures when changing the temperature regime;
inspection tees designed to remove contaminants.

The presence of a large assortment of additional components can greatly reduce the cost of erected structures. Sandwich chimneys are easy to assemble. Their installation can be carried out independently, without the involvement of specialists.

Modern chimneys can be made:

From brick. Since such a structure has a significant weight, it is necessary to build a solid foundation for it.

Advice! Experts advise adding lime to the composition of the mortar used for brickwork, which will avoid the formation of condensate, which has a detrimental effect on the walls of the building.

Chimney lined with bricks

From sandwich pipes, which are made of two layers of metal with a heater laid between them. The most commonly used material for the manufacture of such pipes is stainless steel. In most cases, basalt acts as a heater.
from polymeric materials. Such pipes should not be exposed to excessively high temperatures, therefore such chimneys can be used for gas water heaters and small boiler rooms. At the same time, polymer pipes are very durable, easy to install and have a low price.
From ceramics. Such pipes are characterized by high strength, but they cost a lot. Therefore, they are most often used for arranging industrial-type chimneys. Due to their significant weight, such structures, like brick ones, require laying the foundation.

External ceramic chimney of block type

Important! In some situations, combinations of materials intended for the manufacture of chimneys are possible. For example, a polymer or metal chimney can be lined with bricks.

oven ordering;
fireplace arrangement;
ordering barbecue and all in the same vein.

ensuring proper draft, with the help of which all substances harmful to human health, formed as a result of combustion, are removed outside the living quarters. If unacceptable substances enter the house, then a person can get severe poisoning that can lead to death;

Deaerator type selection

Modern chimneys must be durable, because they have to withstand high temperatures, provide smoke removal at any temperature, resist condensation and aggressive acids. The owner of a private house usually chooses one of the most popular types of chimney:

From brick.
From ceramics.
From stainless steel.

Chimneys are also made of concrete and even glass. Glass is an eternal material that is absolutely not subject to corrosion. But due to the cost, this is a future option for now. For reasons of economy, asbestos-cement pipes are sometimes installed - environmentally and fire hazardous. The choice depends on the personal tastes of the owner of the house, as well as on the type of equipment, the characteristics of the furnace. When choosing the type of chimney, consider:

The temperature of the combustion products.
Flue gas pressure.
Presence of condensate.
Volume of released chemicals.
Resistance of pipes to spontaneous combustion of soot.
Required distance from the system.

Previously, chimneys were built of brick (in fact, there was no particular alternative). Building such a system requires minimal cost: sand, clay, brick are always at hand. But now it is not so easy to find a master who can correctly lay down a brick chimney. If the integrity is compromised due to a poor foundation, poor-quality masonry, there is a threat to the security of the house.

A brick chimney is a budget option (although a professional stove-maker will cost more than a steel pipe sandwich chimney), but it should only be used in conjunction with a solid fuel boiler. brick walls with high-quality assembly, they calmly tolerate high temperatures. If soot ignites in the pipe, the brick chimney will not be significantly affected.

Boilers for liquid or gas fuels, as well as pellet and pyrolysis systems, it is recommended to provide ceramic chimneys - the main competitors of brick ones - strong, non-corrosive and surprisingly durable (plus all the advantages of steel systems).

The elements of such chimneys are a ceramic pipe, an insulating layer of mineral wool and a light casing - foam concrete or stainless steel. The cost of ceramic chimney systems is slightly higher than other types, but everything pays off with their long-term operation. Installation of a ceramic chimney must be carried out very carefully and accurately, according to the manufacturer's recommendations. For individual models, for example, foundation reinforcement is required.

Ceramic chimney

If we compare prices, then the budget for assembling a chimney from sandwich pipes is from 1,200 to 5,000 rubles. per meter (depending on the manufacturer, pipe diameter). The cost of a set of ceramics is an order of magnitude higher: from 40,000 rubles.

If the boiler is installed in a room where there is no chimney duct, the best choice there will be a steel chimney-sandwich. It is less durable than ceramics, but it successfully performs its functions - the removal of combustion products. The main advantages of steel chimneys:

Small mass.
Relatively low cost.
Not subject to clogging.
Does not require a special room.
Easy to install and maintain.
Various mounting options.

steel chimney sandwich

Brick and ceramic chimneys are massive, which provides a load on the foundation. As a rule, for such types, an additional foundation is created that is not related to the main one. Therefore, competent installation of a chimney in a boiler room of a private house requires correct engineering calculations.

Attention! When operating two boilers with different characteristics in parallel, a chimney designed for higher loads is selected. Steel pipes with thin walls, for example, are not used for solid fuel boilers: steel can quickly burn out.

The letter F denotes the area of the fireplace portal, it is equal to 75 x 58 \u003d 4350 square centimeters.
The small letter f denotes the cross-sectional area of the chimney, meaning its inner passage. This will be 12.8 x 25.8 = 330.24 square centimeters.

We take the ratio F/f = 7.6%. Now we look at the graph, what we get ... The figure shows that a rectangular chimney will not work under these conditions, that is, it is necessary to choose a round chimney of the same section, and the height of the pipe must be at least 17 meters. Too big for a private cottage?

Then make the chimney area a little larger so that the percentage fits in the calculated height, or replace it with a circular section. Chimneys with a diameter of 80 mm, for example, have an area of 50.24 square centimeters, this will not be enough. Then it is better to proceed from the inverse condition of the minimum required diameter. We can easily find it from a given height. (See also: Making fireplaces with your own hands)

D= √4 x f / P = √4 x 370 / 3.14 = 21.7 cm.

Glass.
Ceramics.
Steel.
Asbestos cement.

It will be difficult to fold a round chimney out of brick. In this light choose suitable material, but keep in mind that when burning gas or diesel fuel in a furnace, asbestos cement should be thrown aside, and glass chimneys are very expensive. In this case, preference should be given to steel that is resistant to aggressive environments. (See also:)

Deaerator
intended to be removed from the processed
water corrosive gases
oxygen and free carbon dioxide.
The choice of the type of deaerator is carried out according to
table, appendix D.

Chimney lightning protection. Lightning protection check.

Ecology of consumption. Manor: Chimneys, as the highest elements of the roof, with a direct lightning strike, are highly likely to take the blow. Taking into account the fact that modern boiler units for private houses have electronic control units with microprocessor circuits, which will inevitably suffer when electric potential enters the gas outlet pipe from discharge, the need to protect pipes from lightning is understandable.

Chimneys, as the highest elements of the roof, with a direct lightning strike, are highly likely to take the blow. Taking into account the fact that modern boiler units for private houses have electronic control units with microprocessor circuits, which will inevitably suffer when electric potential enters the gas outlet pipe from discharge, the need to protect pipes from lightning is understandable.

The danger from the lightning discharge itself and the emerging electromagnetic field, albeit short-term - for microseconds, but at the same time high intensity, is not all. Even if the discharge is diverted by an organized lightning protection system, without internal protection, an electromagnetic pulse, induced currents and the effect of excess voltages from current spreading will most likely have fatal consequences for electronics.

Internal lightning protection is necessary for all electrical and electronic systems of the house, and this protection is solved in a complex - by installing potential equalization systems, additional installation of SPDs and surge arresters of surge arresters for microprocessor electronics.

But the set of measures also includes external lightning protection, which is installed to ensure the fire safety of the house, prevent thermal and dynamic damage, and most importantly, for the safety of residents. Lightning protection can be active (expensive and complex solution) and passive. Passive defense can be mounted by the owner of the house himself, taking advantage of the lack of knowledge and technical skills with the help of specialists in lightning protection and grounding.

Even today, not all private houses have a lightning protection system. building codes and the rules do not require the mandatory equipping of individual houses with lightning protection, and this fact cannot but surprise.

Any human dwelling also needs protection from this formidable natural phenomenon, just like any boiler room or apartment building or public building. Moreover, in today's private house, the number of conductive elements and communications is only growing, but not decreasing.

Roofing - steel or metal tiles, pipelines and wiring, drainage systems and cable heating on roofs, attics and facades of houses - the shortest paths for atmospheric charges.

Private houses, just like any other structures, need a system for intercepting a lightning discharge and its safe discharge into the ground, bypassing all the structures of the house. House owners understand this very well, and lightning rods on the roofs of cottages are no longer a rarity.

Lightning protection, as a rule, is mounted according to the design and calculation for a specific building, complete, from factory-made equipment. But the main elements of lightning protection systems of private houses are strip steel, or a corner for grounding electrodes and copper-plated or galvanized wire for down conductors.

Lightning, as you know, by its nature "chooses" the high elements of the roofs. Protection is necessary at the level of chimneys and ventilation pipes, antennas, much less often the highest are gables and sharp architectural elements of buildings.

Brick chimneys (or ceramic - non-current-carrying) are protected by the installation of rod lightning rods, less often - by a cable system.

Metal, or having metal heads or deflectors, chimneys protect by connecting the head, which will act as a lightning rod for the pipe, and a common roof lightning rod - a cable, mesh or rod mounted on a ridge. But the connection of the metal pipe of the boiler chimney modern model, having an electronic control unit with a microprocessor circuit, cannot be performed in such a simplified way.

Therefore, lightning protection of gas outlet pipes for boilers operating with electronic monitoring and control systems is solved - according to a different scheme. Free-standing vertical lightning rods are separated from the pipes by means of special fastening elements made of moisture-resistant, durable electrical insulating materials.

The minimum distance from the lightning rod to the outer edge of the pipe is 450 mm, to guarantee the impossibility spark discharge from the rod of the lightning rod - to the steel of the pipe. grounding metal pipes is performed not directly in the external enclosing circuit, but through the EMS (potential equalization system).

All roof antennas and ventilation pipes connected to the electronic control units are protected in the same way.

External elements from ventilation pipes, chimneys and antennas, installed not on roofs, but on the facades of houses, are also equipped with lightning protection.

Metal roofs protect against direct lightning strikes by a system of horizontal and vertical lightning rods. metal roof coverings individual houses, as a rule, cannot serve as part of a lightning protection system, since they do not reach the parameters at which such a scheme is allowed.

Thickness sheet metal roofs are insufficient to withstand a lightning strike without burning through, and the underlying structures are battens and rafter system wooden and easy to catch fire. That's why metal roof protect in the same way as the thin-walled steel of chimney and ventilation pipes. Metal structures made of steel of small thickness will not withstand direct discharge, and burn-through and melting can cause ignition and destruction of house structures.

from which it can be seen that oscillations occur around a displaced equilibrium state corresponding to the static (average) loading component. The calculation results represent the individual components of the dynamic response Xid and the total value of the static and all dynamic components. In this case, the sign of the dynamic addition is taken to be the same as that of the component X c.

Rating of the best economic universities in Russia Rating of universities in the direction of economics

Embossing Card embossing on the spot

How to calculate the parameters of the chimney. Calculation of a chimney: how to calculate the necessary parameters Calculation of a chimney steel pipe of a boiler room