Chimney Pipes And Their Varieties With A Description And Characteristics, As Well As Installation Features

2024 Author: Bailey Albertson | [email protected]. Last modified: 2023-12-17 12:53

Chimney pipes: types, characteristic features, advantages and disadvantages

The owner of any heating installation that generates heat by burning one or another type of fuel has to decide what to make a chimney for it. There is something to think about: materials suitable for this purpose are not one or two, but a dozen. To make the right choice, their strengths and weaknesses should be carefully analyzed, which we will now do.

Content

• 1 Types of pipes for the chimney

  • 1.1 Ceramic pipes

    • 1.1.1 Installation of a ceramic flue
    • 1.1.2 Video: instructions for installing a ceramic chimney

  • 1.2 Stainless steel and galvanized steel pipes

    • 1.2.1 Installation features
    • 1.2.2 Video: sandwich chimney installation

  • 1.3 Vermiculite pipe

    1.3.1 Installation of a vermiculite flue

  • 1.4 Asbestos-cement pipe

    • 1.4.1 Installation of an asbestos chimney
    • 1.4.2 Video: asbestos-cement pipe in the furnace business

  • 1.5 Aluminum and steel corrugated pipes

    • 1.5.1 Installation of corrugated pipe
    • 1.5.2 Video: chimney and ventilation in the garage
  • 1.6 Plastic pipe

• 2 Chimney passage through the roof

  • 2.1 Roof chimney apron
  • 2.2 Video: how to make the passage of the chimney through the ceiling and walls fireproof

• 3 Insulation and sealing of the chimney

  3.1 Video: do-it-yourself chimney insulation

Types of chimney pipes

A chimney for a powerful boiler house or industrial enterprise, which, according to sanitary standards, must have a significant height, can only be built of brick or reinforced concrete. These materials are extremely durable and heavy. Therefore, the chimney built from them at any height does not have to be fastened with stretch marks.

Brick pipes are characterized by high weight, sophisticated masonry technology and maximum stability

But for low-power boilers and stoves used in residential buildings, baths and other small objects, the construction of a concrete or brick pipe can hardly be considered justified. She has too many flaws.

1. Significant weight, which, at a low height, turns from an advantage into a disadvantage: it is necessary to build a foundation under the pipe.
2. Complexity and long term of installation.
3. The need to use a professional bricklayer, which makes the structure expensive.
4. The rectangular shape of the smoke channel, which the brick pipe has at a small cross section. Unlike a round one, in such a channel, swirling smoke (rotation is caused by uneven heating of the walls) forms vortices at the corners, which leads to a deterioration in thrust. However, it should be noted that special chimney reinforced concrete blocks are devoid of this drawback: inside they have a round channel.
5. The surface of the material is rough, as a result of which it quickly overgrows with soot.
6. Low resistance to acid condensation. Due to their porosity, the pipes absorb condensate well, and when it freezes (if the furnace is not heated for some time), it causes microcracks to appear.

There are many alternative materials that are much better suited for small chimneys.

Ceramic pipes

Ceramic chimney pipes have a length of 330 mm and a diameter of 150 to 450 mm. The structure is three-layer: inside there is a ceramic pipe made of refractory clay with a wall thickness of 15 mm, it is surrounded by a layer of stone wool (heat insulator), and outside there is also a protective casing made of expanded clay concrete.

In addition to smooth ceramic pipes, various elements are produced that allow you to mount a chimney of any configuration

In addition to pipes, the manufacturer provides everything necessary for a chimney device:

• condensate trap with drain fittings;
• a section with structural elements that allow you to connect a heat generator to the chimney;
• section with an inspection and cleaning hatch (revision);
• a protective element designed to be installed on the pipe head in order to protect the insulation from atmospheric moisture;

• spark arrester.

  

  The ceramic pipe passes inside blocks of expanded clay concrete, which provide its insulation and protection from mechanical damage

Kits with one or two smoke channels are available, as well as a combined version of a chimney with a ventilation channel.

At the moment, ceramic chimneys can be considered one of the most progressive solutions, which is explained by their many advantages:

• the customer receives a ready-made kit, in which all modules are ideally matched to each other, so that installation is easy and quick
• the parameters of the smoke channel are ideal: the cross-section is round, the wall is smooth and waterproof;
• there are no restrictions on smoke temperature;
• additional work on insulation is not required, since all modules are initially insulated;
• the service life guaranteed by the manufacturer is 30 years.

Of course, there are also disadvantages.

1. High price. This is the main reason why ceramic chimneys have not yet become widespread among private owners. It is useful to know that cheaper versions are produced with less heat resistance, intended for servicing heat generators with low-temperature exhaust - gas water heaters, condensing boilers, etc.
2. Significant weight, because of which it is necessary, as for a brick chimney, to build a foundation.
3. There is no way to get around obstacles - the ceramic chimney can only be strictly vertical.

Installation of a ceramic chimney

The chimney made of ceramic modules is erected on a horizontal foundation that is not connected with the foundation of the house. Combining the foundation with the foundation of the heat generator is allowed. The first module is installed on a cement mortar, all the rest are laid as follows:

1. A special solution resistant to acids (supplied by the manufacturer) is applied to the end of the concrete casing of the installed module using a template.
2. The casing of the next element is placed on the concrete casing.
3. Insulation is inserted into the casing.

4. They coat the end of the ceramic pipe with a special heat-resistant sealant and insert it into the insulation so that the processed end is in the socket of the previously installed ceramic pipe.

   

   The end of the pipe is coated with sealant and inserted into the socket of the previous element

5. With a damp cloth, remove the excess sealant that has protruded into the smoke channel. If this is not done, the joint will quickly become overgrown with soot.

6. If the newly installed ceramic element is a revision or a unit for connecting to a heat generator, then a hole is cut in the concrete casing and insulation, which opens access to the side pipe.

   

   If the element is equipped with an inspection hatch, then a corresponding hole must be cut for it in the concrete casing.

During installation, the verticality of the chimney should be controlled with a plumb line.

This can be done in several ways:

• place reinforcing bars with a diameter of 10 mm in special holes (holes are pre-filled with non-shrinking concrete or cement milk);
• fix a reinforcing frame made of corners and transverse tapes outside the pipe;
• perform concreting with reinforcement laying along the entire pipe from the very base (the most reliable method).

The gray concrete casing looks unpresentable, therefore, in order to increase its aesthetic appeal, the pipe above the roof is usually lined with decorative brick, stone or some kind of roofing material.

Video: installation instructions for a ceramic chimney

Stainless steel and galvanized steel pipes

Steel chimneys have become very popular by now. When compared with ceramic, there are a number of advantages:

• low weight, due to which installation is simplified and there is no need to build a foundation under the pipe;
• the ability to shift the axis of the chimney with the help of taps or even lay it horizontally (option for turbocharged heat generators);
• high heating rate, due to which condensate is formed in small quantities when the furnace is fired.

Due to the smoothness of the steel pipe, soot settles on it rather moderately.

Elements of a stainless steel chimney have sockets on one side, ensuring their tight connection with each other

Pipe sections are available in lengths of 0.5 and 1 m. In addition to pipes, manufacturers make any additional elements and parts that may be required for the chimney device, including brackets for attaching the pipe to the wall, clamps, deflectors, spark arresters, etc.

Pipe sections, tees, revisions and bends (these elements are called modules) have a bell on one side, due to which a tight fixation of one part in the other is ensured. The manufacturing accuracy is very high, so the installer does not have to spend time selecting suitable parts or adjusting them. In addition to the socket, flanged or bayonet connections are used in various models.

The modules are available in two versions:

• single-circuit, that is, without insulation;
• double-circuit: the element is wrapped in basalt wool, on top of which a protective steel casing is installed.

A two-circuit system is also called a sandwich chimney. The thickness of its thermal insulation can be from 20 to 60 mm, so you can choose the right model for any temperature conditions.

The sandwich chimney is a three-layer structure, in which the role of the middle layer is played by insulation

Single-circuit chimneys are used only indoors or only in warm seasons. In the cold, the smoke in such a pipe will quickly cool down, which will lead to a significant decrease in draft and abundant condensation of steam, which, due to reactions with various oxides, will immediately turn into an acidic cocktail. Single-circuit steel pipes are also used for casing brick chimneys.

For coal-fired boilers and stoves, modules should be chosen from the most expensive and resistant steel (AISI 309, 310, etc.) with a maximum wall thickness; for gas installations, simpler and cheaper brands (AISI 304, 321, etc.) are suitable.

Installation features

The very first module connected directly to the flue gas outlet of the heating installation must have a single-circuit design. The flue gases in this area have a high temperature, so if a steel pipe is overlaid with thermal insulation, thereby eliminating heat removal, it will quickly burn out.

The first chimney element to be connected directly to the boiler must be single-walled

The module is fixed on the flue pipe with a clamp and special heat-resistant sealant.

Next, a sandwich pipe is connected to the single-circuit module, the heat insulator of which should be closed from the end with the plug provided in the kit.

The technology for attaching one module to another looks like this.

1. If possible, the inner element is slightly pushed out of the thermal insulation - this will make the installation more convenient.
2. Having lubricated the extended end with a sealant, it is inserted into the bell of the previously installed module.
3. The thermal insulation and the casing of the new module are pushed back against the previously installed one, after which the edge of the casing is put on the head of the already mounted section.
4. Tighten the overlap place with a clamp.

The assembly of a steel chimney can be done in two ways.

1. Install the modules with the flare down (towards the boiler) so that the next part is put on the previous one. This method favors the outflow of smoke, which is why it is called “smoke connection”.
2. Install the modules with the socket up (away from the boiler) so that the next part is inserted into the previous one. Such a connection ensures unhindered drainage of condensate and excludes the latter from getting through the seam into the insulation, therefore it is called "condensate connection".

Horizontal sections should be mounted "by smoke", vertical sections - "by condensation".

Vertical sections of the sandwich chimney must be installed only "by condensate"

If the nozzle of the furnace or boiler is facing up, the chimney can be supported directly on it. But more often the branch pipe looks to the side, so you have to start the chimney with a horizontal section. In this case, the vertical part is allowed along the wall, to which brackets are screwed every 2 m to fix the pipe. At the very bottom, a bracket with a support platform is installed, which will support the weight of the entire structure.

With a significant height of the chimney, an unloading bracket with a special sleeve is installed closer to the roof - it holds the weight of the upper section of the pipe

The horizontal section should be laid with a slope away from the boiler, which will ensure that the condensate drains into the condensate receiver. If necessary, to shift the vertical axis to bypass an obstacle - a rafter leg or a floor beam - use 45-degree bends.

If the height of the chimney above the roof exceeds 1.2 m, its upper part is fixed with braces, for fixing which a special clamp with three lugs is put on the chimney.

Video: installation of a sandwich chimney

Vermiculite pipe

This is how steel pipes are commonly called, which have a vermiculite coating inside. Vermiculite is a mineral with refractory properties. With the help of high-temperature exposure, it is subjected to delamination and the so-called swelling, as a result of which the material becomes porous. Thus, expanded vermiculite is an effective refractory heat insulator.

Vermiculite belongs to the group of hydromicas with a layered structure, and after exposure to high temperatures, it becomes porous

The thickness of the vermiculite layer in the pipe is 50 mm. From the inside, it is treated with a special mastic that penetrates 10-15 mm deep, which imparts moisture resistance to the porous material.

In comparison with a sandwich pipe, vermiculite is advantageous in that it has only one steel circuit, and the cheapest steel can be used - galvanized steel. True, due to the high cost of vermiculite itself, the difference in price with a sandwich chimney is not so big: a meter-long AISI316 stainless steel sandwich pipe with a diameter of 150 mm and a thermal insulation thickness of 50 mm costs 4700 rubles, and vermiculite with the same parameters - 4200 rub.

Vermiculite-coated stainless steel pipe, according to the manufacturer, can last at least 25 years.

In addition, the vermiculite pipe has an important drawback: to date, the technology has not yet been developed that allows the application of vermiculite in a uniform layer in thickness. Because of this, the surface inside often has irregularities up to several centimeters high, and there may be sharp protrusions at the joints of the modules. It is clear that such a relief will quickly overgrow with soot.

Vermiculite pipes began to be used relatively recently, so there is no practical data on their durability yet. Manufacturers promise that they will serve for at least 25 years.

Installation of a vermiculite chimney

The structure is assembled and installed in the same way as a steel chimney: pipes, tees and other modules are connected by means of flanges or clamps, brackets are used for wall mounting, etc.

Asbestos-cement pipe

Asbestos pipes attract literally a penny cost, but they can be used as a chimney only with great restrictions. This is due to the low heat resistance of the material: it can withstand temperatures of no more than 300 ^o C. When overheated, the pipe can not only burst, but also explode. But even if only a crack appears in it, this can lead to the most serious consequences: carbon monoxide entering the room will cause poisoning of the residents.

Hence the second limitation follows: solid fuel heat generators cannot be connected to the asbestos chimney, in the flue gases of which, as you know, there is a lot of soot. This is not just a recommendation, but an official prohibition prescribed in the relevant SNiPs.

Thus, an asbestos chimney can only be used for servicing gas heat generators. Moreover, either the installation should be low-power, for example, a gas water heater with an exhaust temperature of about 200 ^o С, or the asbestos pipe should be installed only in areas remote from the heat generator, where the smoke already has an admissible temperature.

In most cases, asbestos pipes can only be installed in distant sections of chimneys, where the temperature of the combustion products is already quite low

At the same time, other disadvantages of asbestos pipes must be taken into account.

1. The porous wall absorbs condensation, which, if frozen, can destroy it.
2. Due to the fragility of the material, it is not possible to cut an inspection hatch in the pipe.
3. It is impossible to make bends from asbestos cement, so the chimney can only be strictly vertical.
4. If the asbestos chimney consists of several sections, then they have to be joined using rubber couplings, which are not very reliable in terms of tightness.

In view of all of the above disadvantages, asbestos pipes are used today mainly for building up to the required height of the smoke channels laid inside the walls.

Installation of an asbestos chimney

The asbestos-cement pipe is simply inserted into the in-wall channel, installed on a specially made protrusion and lined with mortar.

Video: asbestos-cement pipe in the furnace business

Aluminum and steel corrugated pipes

Corrugated metal pipes have a thin wall and therefore do not differ in durability, but they are indispensable in cases where individual sections of the chimney due to inconvenient location cannot be connected using straight sections and standard bends. In addition, corrugated pipes are used for casing brick chimneys.

As mentioned above, brick pipes do not tolerate contact with acid condensate well. In the exhaust of modern economical boilers, characterized by a low temperature of the outgoing flue gases, it is formed in large quantities. Installing an inexpensive and easily replaceable metal sleeve is a great way to extend the life of your brickwork in these conditions.

Corrugated pipes are made of two materials.

1. Aluminum. It can only be used with low power units.

   

   Aluminum pipes cannot be used with high power installations

2. Stainless steel. Pipes made of this material are used without any restrictions.

   

   With the help of a corrugated pipe, you can repair a brick chimney of any shape

Corrugated pipe installation

Corrugated pipes are connected to the chimney sections and to the flue pipe of the heat generator by means of clamps, sometimes a flange connection is used. If the corrugation is inserted into the in-wall smoke channel, then a decorative rosette is attached to the wall around it.

Sagging of the corrugated pipe must be avoided in long sections. If so, screw the support bracket to the wall.

Video: chimney and ventilation in the garage

Plastic pipe

Pipes made of heat-resistant plastic are used exclusively for casing brick chimneys to which gas water heaters or other installations with an exhaust temperature of no more than 200 ^o C. are connected. Such a liner is much cheaper than steel or aluminum, in addition, it is absolutely not subject to corrosion.

Installation of a plastic chimney is very simple: the pipe is inserted into the flue channel, after which the supply section is connected to it using a clamp or flange connection.

The inlet section is connected to the sleeve using flanges or a clamp

Chimney passage through the roof

In residential buildings, most often they resort to the internal location of the chimney, which allows:

• extend the life of the structure (it is not affected by external factors);
• keep a greater amount of heat generated by the boiler or furnace;
• to ensure the aesthetic appeal of the structure.

With this arrangement, it is necessary to correctly organize the node of the passage through the roof. They usually act in the following sequence.

1. An opening is made in the roofing cake. In the panels of steam and waterproofing, the opening is not cut out, but instead they are cut crosswise, after which the formed triangular valves are folded back and shot to the rafters and crate. The dimensions of the opening should be such that its boundaries are 5–7 cm from the pipe surface.

2. The opening is hemmed from below with a steel sheet, in which a hole is made for the passage of the pipe.

   

   The opening in the place where the chimney passes through the roof is sutured from below with a steel sheet

3. The next section of the chimney is installed, leading it out.
4. The gap between the pipe surface and the elements of the roofing cake is filled with a non-combustible heat-insulating material - mineral wool or basalt cardboard.

5. A so-called apron or penetration is installed - a conical piece that covers the gap around the chimney and adjoins the upper part to the pipe, and the lower part to the roofing.

   

   Conical penetration bridges the gap around the chimney

Roof chimney apron

Aprons for sealing the pipe passage are of the following types:

• for a rectangular pipe, this part can be made independently from several galvanized sheets, connected by a double standing seam;

  

  The apron for a rectangular pipe is made of galvanized metal

• for round pipes, self-adhesive tapes are available in aluminum or lead - soft metals that can be shaped into a roof covering.

In addition, aprons are made of elastic polymers that are resistant to the external environment. Such elements are called rats. The most popular for round chimneys is the Master Flash canopy.

The Master Flash universal pass-through is made of elastic rubber or heat-resistant silicone, so it can be used on any roof configuration

Branded manufacturers of metal and ceramic tiles, ondulin and corrugated board produce special aprons, the lower part of which ideally matches the relief of the roofing material. The use of this part greatly simplifies the sealing of the roof passage assembly.

Aprons are also offered by manufacturers of sandwich chimneys. Usually, such products are produced in three versions, oriented to different roof slopes, so this parameter must be specified when placing an order.

When installing the apron, the places of its abutment to the pipe and roofing must be treated with a sealant for outdoor use. On the pipe, the part is fixed with abutment strips (rectangular chimney) or with a clamp (round), and screwed to the roof with self-tapping screws.

The slate roof passage can be sealed with a cement-sand or mud bead

Video: how to make the passage of the chimney through the ceiling and walls fireproof

Chimney insulation and sealing

As you know, natural draft is due to the tendency of hot gases to move upwards, therefore, for the normal functioning of the chimney, it is extremely important to prevent them from cooling. In addition, less acid condensation is generated in hot smoke, which significantly extends the life of the chimney. Thus, the insulation of the chimney is the most important stage of its arrangement.

Only non-combustible materials may be used as a heat insulator. These include:

• mineral wool (has the lowest thermal conductivity);
• sawdust concrete and foam concrete slabs;
• plaster.

The last two varieties are used to insulate brick and concrete chimneys, all the rest are wrapped in mineral wool.

Having wrapped the pipe with a mineral wool mat, it is fixed with a knitting wire. Further, the thermal insulation must be sealed, since it absorbs moisture and becomes inoperative at the same time. In addition, mineral wool forms dust that is very harmful to the respiratory tract and eyes, so that in the open state it will pose a considerable danger to residents.

Mineral wool heat-insulating layer on top is sealed with galvanized sheet steel

The sealing of mineral wool insulation is carried out using a casing made of galvanized steel, the edges of which are connected with rivets or a seam seam. If the casing is assembled from several elements, they are mounted with an overlap, coating the junction with a sealant. From above, the end of the insulation must be closed with a plug.

Video: do-it-yourself chimney insulation

Different materials can be used for the chimney device, and it is impossible to speak unequivocally about the superiority of any of them over others: each of the materials in different situations may be better or worse. It is only necessary to carefully consider your choice, since if the material does not correspond to the working conditions (temperature and acid exposure), the chimney may depressurize with the subsequent flow of poisonous carbon monoxide into the room.