Heat-resistant chimney sealant: recommendations for selection

Features of the

The unique chimney device consists of three parts:

• inner pipe made of stainless steel of excellent strength and heat resistance;
• heat-insulating material in the form of basalt or ceramic wool, polyurethane foam, vermiculite.
• protective outer tube made of galvanized / stainless steel.

To improve aerodynamics, the designers have provided a cylinder shape. All three layers of stainless steel sandwich pipes are glued together, and some parts of the chimney are mounted, as in drainage pipes, with sockets.

Double-walled sandwiches solve the problem of condensation formation on the walls of the chimney in cold weather due to the insulation included in the structure. This insulation prevents soot from forming on the inner surface and prolongs the service life.

To facilitate the assembly of the prefabricated structure, fittings are available for connection, channel rotation and other functions.

1. The main length of the chimney is carried out in segments of 1 and 0.5 m in length.
2. Horizontal sections (loungers) are connected using revision tees to eliminate pipe clogging.
3. A tee for collecting condensate and cleaning the internal cavity is installed at the beginning of the vertical section of the channel. This often happens immediately after the chimney exits to the outside of the building. One of the outlets of the tee is threaded to remove condensation moisture.
4. The corners for the device for turning the chimney by 90º are made of pipe materials and insulated with an insulator layer.
5. Compensator for smooth changes in the linear dimensions of the sandwich when changing temperatures. In high-rise buildings, it is installed on each floor, and in one-story buildings above the floor.
6. The roof abutment structure is designed as a single unit and serves to form the exit of the chimney channel to the roof.
7. Node for eliminating leakage in the roof outlet. Installation is carried out around the chimney.
8. A tip to keep debris, snow and dust out of the duct openings.

Advantages of stainless steel chimneys

The high performance of these products is due to the properties of the material of manufacture.

A heat-resistant stainless steel pipe for a chimney has a number of advantages over similar devices made of other materials:

• it has a longer service life;
• increased strength characteristics;
• heat-resistant stainless steel makes it possible to create systems of increased complexity when they are executed in a corrugated form.

Corrosion resistance inherent in these products is of considerable importance.

Why are solid fuel devices considered?

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

• First of all, gas heating devices are almost always factory-made products. That is, they must have a branch pipe of a certain section for connection to the chimney. The channel cross-sectional area is also discussed 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.

Factory-assembled boilers or stoves always have a chimney connection. That is, the problem with the cross section of the chimney is no longer worth it - it should be no less than that specified in the technical documentation.

• The temperature of the gas combustion products leaving the chimney is incommensurably lower than that of the wood or other solid fuel generated during combustion.
• It is also difficult to compare the volumes of gas mixtures formed during the combustion of "blue" and solid fuel. The difference here is quite significant!

But solid fuel heating devices, stoves or boilers are very often created independently. Or they are "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, it can be fully attributed to gas heating equipment. The cross-section is known, but it doesn't hurt to check the rest.

But let's start with the section.

Types of stainless steel chimney sealant

Thanks to the sealing of the chimney or chimney slots, combustion products do not enter the room through them. Reliable insulation makes the use of a stove, fireplace or boiler as safe as possible.

Watch video - high-temperature agents for stainless steel and other materials

All sealants can be roughly divided into several types:

• based on silicone or silicate;
• by composition: one-component or two-component;
• by temperature characteristics: temperature-resistant sealants and heat-resistant.

As the name suggests, one-component sealants are made up of one component and do not require mixing of the ingredients prior to the sealing procedure. This makes them easy to use and popular with homeowners who value the ease of use of the insulation product.

Two-component, before starting work, must be mixed, clearly observing the proportions indicated in the instructions. In this case, the finished product should be used within a few hours after mixing. This option is not very suitable for sealing joints with your own hands, usually professional builders use two-component insulation.

In addition to insulating the chimney, sealing compounds are also used to insulate the seams of the construction of a heating system based on an electric boiler when eliminating pipe leaks.

Beneficial use of double pipes

The correct approach and competent study of the main nuances will help you install the chimney sandwich yourself.

Due to this characteristic, a separate foundation for the oven is not required.

• Compactness, which, combined with lightness, allows you to easily transport products to their destination.
• Simple repair, thanks to which specialists can easily replace one of its parts in the chimney.
• Variety of fittings that will help you install the device with an exit through a roof or wall.
• The presence of a heat-insulating layer between the pipes, which allows the temperature to be reduced from the outside.

This advantage is aimed at improving the fire safety of the structure.

• Lack of stagnation and the possibility of effective smoke removal, because the inner surface of the pipe has a flat cylinder shape.

That is why so little soot is formed in the chimney pipes made of stainless steel sandwich.

• Anti-corrosion materials from which the products are made, therefore, condensate and chemical compounds of a destructive effect do not accumulate on the walls of the latter.
• Ease of operation. Regular preventive inspections of chimneys are, of course, necessary, but the design nuances of such products allow them to be performed not so often.
• Attractive appearance. Sandwich pipes do not need any additional finishing and they look great both outdoors and indoors.

Silicone sealants for stainless steel, glass and other materials

When wondering how to seal a chimney made of stainless steel, glass, plastic or ceramics, you should pay attention to fireproof silicone. This material contributes to the tight contact of structural parts to each other and reliable insulation.The main advantages of the silicone composition:

• due to elasticity, the quality of contact is maintained for a long time, even when, due to high temperatures, the structural elements are deformed and change position relative to each other;
• after the completion of the polymerization process, the material becomes very durable;
• silicone is absolutely waterproof;
• the material has a high degree of resistance to ultraviolet radiation and other weather conditions;
• silicone is characterized by high heat and heat resistance.

There are two types of silicone sealants:

1. Acidic. They release acetic acid during hardening, which can damage the pipe or roofing. Such a tool will definitely not become an assistant in solving the problem of how to seal a chimney made of stainless steel or a material of natural origin: cement, stone or concrete, as it can contribute to the formation of corrosion of metal elements, destruction of the sections of the pipe and roof in contact with it.
2. Neutral insulation agents, unlike acidic ones, release water and alcohols into the environment when they harden. It is a suitable sealant for stainless steel chimneys.

An additional plus of silicone-based products - as a result of heating, the iron oxide entering it turns brown, which makes the insulation more invisible against the background of a roof or brickwork.

How to calculate the chimney cross-sectional area?

There are several methods for calculating the optimal section. For example, from the size of the hearth combustion chamber or from the area of ​​the furnace blowing window. 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 combustion.

The combustion of wood and other solid fuels is always accompanied by a very significant smoke generation. And the chimney must be able to divert these volumes to the outside in a timely manner.
On the basis of calculations and experiments, specialists have long compiled tables from which it is possible to obtain information on the specific smoke production for different types of solid fuels. That is, what volume of combustion products is formed when burning, say, one kilogram of firewood, coal, peat, etc.

We will also present 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 exit from the chimney. The first of these characteristics is not of particular interest to us at a given moment - it just gives a general idea of ​​the fuel efficiency. But the temperature, yes, is needed for calculations.

Fuel type	Specific calorific value of fuel, kcal / kg, averaged	Specific volume of emitted combustion products from combustion 1 kg, m³	Recommended temperature at the exit from the chimney, ° С
Firewood with an average humidity level - 25%	3300	10	150
Peat lumpy (in bulk), air drying, with an average moisture level not exceeding 30%	3000	10	130
Peat - briquettes	4000	11	130
Brown coal	4700	12	120
Hard 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 the minimum smokiness are already about 10 cubic meters for each kilogram burned. This means that simply for reasons of physics and geometry, the cross section of the chimney should be able to constantly divert these considerable volumes out.

From this and "dance" when calculating.

chimney

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

Vgh = Vsp × Mth × (1 Td / 273))

Vgч is the volume of combustion products generated within an hour.

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

Mtch is the mass of the fuel load burned during one hour. It is usually found as the ratio of the total 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. This means that Mtch = 12/3 = 4 kg / hour.

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

273 is a constant to bring the temperature parameters to the Kelvin scale used in thermodynamic calculations.

We suggest that you familiarize yourself with the Wood-burning water heater with your own hands

Vgс = Vgч / 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 gas movement, it is necessary to find their ratio

Sc = Vgc / Fd

Sc - cross-sectional area of ​​the chimney channel, m2.

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

A few words about this speed. For heating devices and structures of a household class, they usually tend to stop in the range from 1.5 to 2.5 m / s. With this, on the one hand, low speed, there is no significant resistance to the flow, there are no strong eddies that slow down the movement of gases.

If a cross-section is found (and this is its minimum value), then according to the known geometric formulas, one can find either the diameter for a pipe of circular cross-section, or the length of the side - with a square cross-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 is necessary to indicate the type of fuel, the approximate consumption of its consumption (more precisely, the mass and burnout time of the full load) and the expected flow rate of gases in the chimney. The program will do the rest by itself.

- the minimum diameter for a circular section;

- the minimum side length for a square section;

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

Go to calculations

Stainless steel: design nuances

There are many types of chimney materials for private homes. The pipes are divided depending on the purpose and functionality.

Insulated double-layer pipes allow the inner part to heat up as quickly as possible and contribute to the efficient removal of smoke from the combustion center. They are installed outside the building in cases where it is not possible to carry out the internal wiring of the chimney.

The installation of a chimney sandwich can be ordered by specialized builders, but if you understand all the intricacies of the technology, you can install the smoke channel yourself.

This material is quite resistant to temperature extremes and has excellent anti-corrosion properties. Internal stainless steel products can withstand temperatures of 850̊C and even drops up to 1200̊C.

In the production of sandwich pipes, two grades of steel are most often in demand: 310S and 316 Ti. The temperatures of the working media for these materials are quite high, the maximum threshold reaches 1000 ° C. These two grades of stainless steel are especially preferred in chimney designs for baths and solid fuel boilers, where very high temperatures must be withstood. Such chimney products will last a very long time.

If you are looking for a high-strength construction, then the ideal option would be to manufacture the inner and outer shell of the pipe from one stainless steel.

The thickness of the insulating layer affects the dimensions of the pipe section. In addition, the diameter of the chimney sandwich pipe depends on the location of the device. Internal pipes are selected depending on the power of the heater. The larger it is, the larger the cross-section of the product should also be.

Here are the main indicators of the dependence of the pipe diameter and the capacity of the furnace structure:

• cross-section of the product 50-600 mm - for gas turbine plants and wood-fired ovens;
• diameter 50-700 mm - for solid fuel boilers;
• 50-500 mm - for diesel generators and gas piston devices;
• 50-300 mm - for microturbine devices;
• up to 200 mm - for gas or diesel boilers.

We must not forget that it is not recommended to use fiberglass as a heat-insulating layer, because it retains its operational characteristics only at a temperature not exceeding 350̊ С. And in structures for baths this indicator reaches 600̊ С.

Chimney pipes made of metal

One of the most used materials in construction is metal, this fully applies to the arrangement of chimneys. Being very plastic, it allows you to create quite complex systems, while maintaining its main quality - strength.

Video

The heat-resistant stainless steel pipe possesses special properties, which, in addition to high strength characteristics, has an ideal appearance. The stainless pipe is very durable, practically does not corrode and is resistant to mechanical stress.

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 chimney height with great accuracy. 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 ecological component for the emission of combustion products to a certain height.

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

In this case, it is precisely the height difference between the outlet from the device (for furnaces it is often considered - from the grate) to the upper edge of the pipe, without taking into account the worn umbrella, weather vane or deflector. This is important for those chimneys with horizontal or inclined sections. Let's repeat - not the total length of the pipe used, but only the height difference.

The height of the chimney is precisely the height difference between its inlet and outlet, and not the total length of the chimney, on which there may be horizontal or inclined sections. By the way, you should always strive to minimize the number and length of such sections.
So, the minimum length is clear - five meters. Less is impossible! More? Of course, it is possible, and sometimes even necessary, since additional factors may intervene due to the specifics of the building (corny - the height of the house) and the location of the pipe head relative to the roof or adjacent objects.

This is due to the rules of fire safety, and the fact that the head of the pipe should not fall into the so-called zone of wind support. 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 be reversed (“topple over”).

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

chimney

Basic rules for the location of chimneys relative to the elements of the roof of the building

• First of all, no matter what 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 support zone is determined by a line drawn at an angle of 45 degrees.The cut-off of the chimney must be at least 500 mm higher than this conditional line (in the upper figure - the left fragment) ..
• By the way, the same rule applies even then, for a year, there is a tall third-party object next to the house - a building or even a tree. The figure below shows how the plotting is done in this case.

Tall trees near the house can also create a zone of dense wind backwater.

• 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).

- A 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.

- With a distance from 1500 to 3000 mm, the upper edge of the pipe must not be below the level of the ridge.

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

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

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 height - from 5 meters or more.

We offer you to familiarize yourself with How to make a bench in a bath with your own hands

Chimney installation

All of the listed types of pipes are good because they can be mounted independently. However, the installation of the chimney with your own hands must be carried out in compliance with the following installation rules:

• the minimum height from the grate or burner to the cut of the vertical pipe is 6 m;
• the length of the horizontal section from the boiler nozzle to the insert into the chimney tee is 1 m. The section is mounted with a slope towards the tee so that condensate does not get inside the heater;
• the number of turns for the entire length of the chimney - no more than 3;
• the joints of the modular chimney sections should not fall into the passages through walls and ceilings;
• when crossing building structures made of combustible material, an opening of such a size is made to provide a gap between the wall or ceiling of 200 mm. Then it must be filled with basalt fiber and flanges for the chimney must be installed on both sides;
• the minimum diameters of the chimney pipes must be equal to or larger than the outlet on the boiler;
• the assembly of the circuit is always performed "by condensate", which will be discussed below;
• at the bottom of the vertical section, a condensate collector with a drainage pipe is installed;
• the top of the chimney must be at a certain height, as shown in the chimney diagram.

During installation, the corrugated pipe is stretched to the required length and put on the branch pipes. This is the simplicity of its installation; no sealant should be used when joining the elements. The required degree of tightness is provided by conventional chimney clamps, tightened with a small open-end wrench. The horizontal section of the corrugation rests on the brackets so that there is no sagging, the vertical one is fastened with clamps with fasteners to the wall.

The assembly of modular single - and double-walled systems must be started from the boiler in accordance with the installation diagram prepared in advance. In this case, the elements are connected "by condensate", that is, when each section is inserted into the bell of the previous one. When assembling a sandwich, the inner part is joined in the same way, but the outer part is the opposite. The outer diameters of the chimneys of the next section should be larger (have a bell) and fit over the previous ones. Both the condensate inside and the precipitation outside will then calmly flow down.

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 thrust, it will never be superfluous to check the strength of this very thrust.So that it does not happen that the built chimney suddenly refuses to fulfill its main functions.

Draft is, in fact, the pressure difference 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 pascal for each meter of pipe height (0.408 mm water column or 0.03 mm Hg). That is, for a five-meter pipe (our minimum), the thrust must be at least 20 Pa. This ensures both the normal evacuation of gases and the necessary supply of air for the continuous combustion of the fuel.

ΔP = Htr × g × Patm × (1 / TV - 1 / Tds) / 287.1

ΔP - natural draft in the pipe, Pa.

Htr - chimney height, m.

g - acceleration of gravity (9.8 m / s²);

Patm - atmospheric pressure. A value of 750 mm Hg is considered normal. However, the area for which the calculation is carried out may have its own specifics. It must be understood correctly that sea level is considered the norm. And with an increase in altitude, 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 the calculation in the SI system, it is required to translate it into pascals. This is not difficult if you know that 1 mm Hg. Art. = 133.3 Pa.

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

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

287.1 - gas constant of air. 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, strongly 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 removal, heat builds up in the steam room in a short time, and the chimney usually heats up to dangerous temperatures. Therefore, you need to be able to control the temperatures in the pipe using available means - gates, valves, devices for additional heat recovery (for example, hot water tanks).

In household and heating stoves, this is easier, but control is still necessary. In boilers, where the very essence of the work lies in the constant release of heat to the circulating coolant, these questions are not so acute.

The 900 ÷ 600 ℃ mode (entry and exit), found in some sauna stoves, is extremely dangerous in all respects, and should not even be considered! A reasonable framework (and even then - their upper limit) is 600 ÷ 400 degrees for household brick and metal stoves. Usually, they try to withstand in the range of 400 ÷ 200 ℃. For gas equipment, the lower limit may 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.

Go to calculations

If the obtained pressure difference falls within the norm (more than 4 Pa ​​per meter of pipe height), then the check can be called successful.

The main parameters of the chimney have been obtained - you can proceed to the choice of materials and detailed design.

Sandwich pipe installation: highlights

All work on installing a sandwich chimney begins with marking and cutting out all the necessary technological holes. This refers to the ceiling or wall, as well as the roof itself.It should be borne in mind that the distance from the pipe to unprotected wooden structures should not be less than 40-45 cm. For fire safety purposes, let it be more than less. Otherwise, the use of protective screens is imperative!

Options for sandwich pipes for a bath

Installation of the "designer-chimney" is started from the bottom up. First of all, a single-circuit pipe is installed on the furnace. Due to the lack of insulation, heat transfer is significantly increased. For example, a single-circuit sandwich pipe for a bath can be completed with a hinged one. It is possible to use a cylindrical metal mesh for stones, which greatly increases the efficiency of the stove. The use of special economizers-convectors on the first chimney segment also increases the heat transfer coefficient.

The so-called starter adapter is mounted on the installed "single-circuit sleeve". It is needed in order to reliably and beautifully connect a single-wall pipe with a sandwich. Then a gate is mounted to adjust the draft level or a double-circuit chimney is immediately put on.

The following nuance should be clarified: sandwich pipes can be assembled in two ways ("by smoke" and "by condensate"). "On smoke" is when the upper pipe is pushed onto the lower one. At the same time, the smoke does not meet any obstacle. “By condensation” - the opposite is true: the upper segment is inserted into the lower one. For an optimal result, we put on the inner pipe sleeves “for smoke”, and the outer ones “for condensate”. For a better sealing effect, it is advisable to use a special heat-resistant sealant and crimping clamps.

Calculate the height of the chimney to the ceiling in such a way as to exclude the junction of the segments in the area of ​​overlap. This will increase the degree. And now the most important point. Many people consider sandwich chimneys to be the absolute standard of safety and do not install a passage box in the ceiling passage, relying only on the thermal insulation of the pipes themselves.

The result is often very disastrous. It is compulsory to use the pass-through ceiling box. It will protect wooden structures from heat and fire. It can be covered with expanded clay, but not with sand. It is possible to use the same mineral wool as a heat insulator.

When passing the chimney through the roof, it is reasonable to use an element such as a flash master

... This is a special sealant for roofing passages, which in the common people is called a "flash drive". The element is necessary and practical, you cannot do without it. Here, a metal element of the roof cut is also used, which ensures a reliable and stable position of the chimney.

Chimney support bracket

Portable enamel sandwich

Ceiling cut

Depending on the design of the chimney, a "revision" is sometimes installed in the lower part. This sandwich pipe element is usually installed on a side chimney, which has a horizontal section. There is a small door for. A very convenient and necessary moment.

On the upper part of the chimney, spark arresters, umbrella-deflectors are installed. Purpose: to extinguish sparks and protect the pipe from atmospheric precipitation and debris.

When installing sandwich pipes for a chimney, you should exclude their touching various communications (electrical wiring, gas pipelines, water and sewer pipes, ventilation ducts). Following the manufacturer's instructions for assembling such a "constructor", you can easily do the installation of a chimney from a sandwich pipe with your own hands. It will not be difficult, although you still have to “move your brains” and work with your hands.

Quote of wisdom: He who does not need someone else's, but lives independently, is richer than everyone.

Between the two pipes of the chimney structure (external and internal) there is a material for thermal insulation. Basically, it is mineral wool (basalt or ceramic).

We offer you to familiarize yourself with Ventilation from sewer pipes - myth or reality?

Sometimes the natural material vermiculite acts as a heater. To use it for its intended purpose, it is preliminarily crushed to a granular state, and then fired in a special furnace.

Such procedures are necessary to obtain the highest quality characteristics:

• resistance to high temperatures and their drops;
• low weight;
• strength, etc.

Vermiculite is much more expensive than mineral wool, but it is distinguished by the ability to maintain its quality characteristics at an operating temperature of the chimney of 1150̊ С.

But ceramic wool is more heat-resistant and can withstand an operating temperature of 1260̊C, i.e. more than twice that of the previous material. Accordingly, the price of sandwiches with such a filler will be higher than pipes with basalt wool or vermiculite.

It is important to remember that the dimensions of the chimney sandwich pipe depend on the diameter of the boiler outlet. During installation, the product is mounted on it; therefore, the cross-section of the sandwich pipe must necessarily exceed the outlet pipe.

Today, chimney sandwiches with a cross-sectional area of ​​0.5 and 1 m are more in demand, but there are also diameters in the range of 110-300 mm. In the line of standard sizes of pipes for a chimney structure, there are other options, but much less often.

Pipe connecting elements have corners:

• 90̊ С - for corners and tees;
• 135 ° C - only for tees.

The thickness of the inner wall is 0.5-1 mm, and the outer wall is 0.7 mm. The indicator of the thickness of the layer of internal thermal insulation ranges from 2.5-6 cm, and the outer diameter of the sandwich structure is 200-430 mm.

Types of connecting elements

The heating device, in addition to sandwich pipes, includes other fittings, for example:

• chimney-convector, used for the exit of combustion products outside the building;
• knee, consisting of several parts, which are joined together at an appropriate angle. With the help of the knee, you can change the direction of the output of combustion products;
• a tee that performs the function of removing condensate and smoke is used very often;
• an adapter for connecting some pipes, the most common element;
• revision - to clean the structure from soot;
• kagla regulating traction;
• rosette - for decorating the chimney;
• weather vane and cone that protect the heating system from natural precipitation;
• a fungus made of galvanized steel sheet, which protects the chimney structure from snow and rain. Installed at the very edge of the outlet pipe.

All these connecting elements can have diameters: 120, 150,200 mm and are used depending on the design features of the chimney device and other factors. The diameter of the inner pipe always corresponds to the size of the chimney sandwich and its accessories.

How to choose a chimney sandwich

When purchasing smoke exhaust elements, it is required availability of a factory certificate with a description of its characteristics, which include the name of the categories of boilers for possible connection, the warranty period and types of fuel. In the absence of a certificate, use the right to purchase elsewhere.

For craftsmen who want to create a smoke outlet with their own hands, there should be detailed instructions.

Pay attention to the stainless steel of which the sandwich is made. The quality of this material affects the service life and resistance to high temperatures.

The heat insulator inside the cavity must withstand up to 650º without deformation.

For solid fuel boilers, products are purchased with laser-welded seams and inner tube made of stainless steel... For boilers using gas fuel, it is allowed to connect the elements using the rolling method and the cavity inside each of the galvanized sheets.

External elements can be made of galvanized steel, polyester, brass, stainless steel.

Sizes of stainless steel sandwiches

When purchasing pipes, it is necessary to take into account the diameter of the outlet of the pipe from the boiler. The corresponding indicator of the pipe should not be less than it. The sandwich pipe must be worn on the outlet.

• Internal pipe diameters are commercially available: 110 mm, 115 mm, 120 mm, 150 mm, 200 mm and up to and including 300 mm.
• The length of the sandwich segments for sale is half a meter and one meter.
• The wall thickness of the inner tube is made 0.5 mm and 1 mm.
• The outer diameter is produced from 200 mm to 430 mm.
• Rotation corners are sold at 90º. Tees for 90º and 135º.
• The thickness of the inner insulation ranges from 4 cm to 6 cm.

Choosing the right chimney

The dimensions of the chimney used simultaneously for several heating devices is a separate topic for conversation.

If it is necessary to remove smoke from a number of heating devices, then the chimney is calculated taking into account all heating devices used in the system, their type, power, fuel consumed.

• For example, in a house with a single chimney, several heating devices, a boiler for a common heating system and a fireplace are installed.
• It immediately becomes clear that we have completely different systems. The chimney diameter of the fireplace does not correspond at all to the diameter of the boiler chimney.
• As a rule, fireplaces run on wood fuel, and boilers for the heating system at home run on natural gas.

Is it possible to combine these 2 completely different systems? Can. Moreover, with the correct placement of heating devices, they not only will not create problems, but will also complement each other.

How does this happen?

• One chimney includes a boiler and a fireplace. During operation, the boiler periodically turns off and goes into standby mode. At this time, we have a fireplace. Therefore, a normal temperature is maintained in the chimney, the gases do not cool down.
• Hence the absence of condensation and good draft during the next boiler start-up.
• But the size of the chimney for the fireplace should be much larger than for the boiler. And if we use only the boiler without starting the fireplace, we may have problems with excessive draft, leading to improper operation of the boiler.
• As we know, the chimney diameter for a fireplace is calculated at a ratio of 1:10 to its firebox. It becomes clear that such a chimney diameter is very large for a boiler. People rarely use the fireplace, and the heating boiler works constantly in the winter.
• So, you need to make a chimney with a smaller diameter, suitable for the boiler? No, that would be a big mistake. When the boiler works on its own, everything will be fine. When the fireplace starts up, increased aerodynamic resistance will be created in the chimney.
  Two-way chimney. Fig. one

As a result:

• improper operation of heating devices;
• ingress of carbon monoxide gases into the room.

This is already life-threatening. Carbon monoxide poisoning is often fatal.

How can this issue be resolved?

Our advice is to use a two-way chimney.

Two-way chimney. Fig. 2

• the possibility of using various heating devices simultaneously and separately in one chimney;
• stable operation of each device;
• savings in construction and installation;
• saving space.

When installing such a chimney, it is necessary to comply with all conditions for the correct operation of each device. If the fireplace can function perfectly with a brick chimney, then a sleeve must be made for the boiler. This will protect the brick from the alkaline effects of condensation.

The "Fireplaces and Stoves" store offers a wide range of stove pipes and chimneys from reliable manufacturers. In our catalog you will find single-walled chimney systems for liner and protection against aggressive condensation of brick ducts. We also have double-walled models with a heat-insulating layer, with the help of which chimneys are equipped outside the room. Sandwich pipes do not allow flue gases to cool down quickly, preventing a decrease in draft in the cold season.

When choosing a chimney for a bathhouse, a cottage or a small country house, it is important to purchase truly high-quality products. This is the only way to ensure the correct operation of modern heating equipment. Our task is to help you make the right decision!

In this case, some factors are important:

1. The high-quality functioning of the entire sandwich structure is in direct proportion to the strength of the material used in its manufacture.
2. Sandwich pipe dimensions.
3. The density of the insulation layer.
4. Type of pipe seam (rolled, laser).

Service life of sandwich pipes

The guaranteed service life for different system products varies from 10 to 15 years. Such an indicator is real only if all the requirements for installing the chimney are strictly observed: the correct choice of material, thickness of the seal, etc. Often all these conditions are not met, therefore the service life is reduced, which ultimately leads to a complete replacement of the chimney after about five years. And it happens that before.

What are the common reasons for early structural failure? There are many of them, but often even a factory defect can disable a structure already at the very beginning of its operation. Therefore, experts recommend with particular care to choose pipes for the chimney and check them for defects.

The timeliness of preventive cleanings in the system is of no small importance. Even with the slightest detection of deviations from the norm in the design, operation should be stopped, and repair work or complete replacement of the chimney should be carried out.

If you follow all the rules when buying and operating a sandwich installation, then it will serve you for a very long time. Otherwise, an accident may occur with the ensuing negative consequences. If you doubt your abilities regarding the correct purchase of components and their installation, then in this case it is better to trust the specialists.

Corrugated stainless steel pipe installation technology

It should be noted that the installation of corrugated pipes is easy to process. Due to the variety of types of fittings, it is quite possible to assemble any system on your own, without the involvement of specialists. The main thing is to observe the sequence of technological stages and the correctness of the work performed during the installation process, which ultimately will allow you to get a strong, reliable and durable pipe connection.

Directly, the installation technology assumes a clear sequence of certain actions:

1. Connecting fittings to pipes and mixers. At this point, make sure that the flare nut on the side of the pipeline connection is not tightened.
2. Cutting off the required amount of material. This is required to be done using a special tool - a roller pipe cutter. The cut should be neat, without burrs.
3. The pipe is inserted into the fitting and the union nut is tightened.
4. The pipeline is fixed in the desired position, using for this purpose special fasteners in the form of clips and clamps.
5. Checking the health of the system. If a leak is detected, tighten the union nuts a little more.

Due to the variety of types of fittings, it is quite possible to assemble any system on your own, without the involvement of specialists.