How to cut a sandwich pipe. Switching to a sandwich chimney – preliminary work

Sandwich chimney installation: how to build and install with your own hands

You dream to build an economical, safe and warm house? Then you should turn to modern technology, which wisely combines centuries of experience, ingenuity and sometimes quite unexpected technical solutions. A good example of this is a two- and three-circuit chimney, inside which is insulated. Who would have thought even a couple of decades ago, that such a thing at all possible? And such a chimney really has many valuable advantages, it is only important to do everything according to the stove rules, not deviating from them not one iota.

Competent installation of a sandwich chimney begins with the design of the house. Only when making a drawing can absolutely all the requirements for fire regulations be correctly met, and then nothing will have to be redone or even rebuilt. If the house or bath is ready, then you will need to make all calculations as accurate as possible. We advise you, if you set out to make such a chimney yourself, to approach this issue with the utmost responsibility. for the same you do.

In this video I want to tell you about the options for installation of a tee and a support platform of a stainless sandwich chimney. Many craftsmen mount a tee above the landing, but I think it makes more sense to do it the other way around. See more details in the video!) I bought it here. Please subscribe to the channel. 6

I’m doing an experiment: How hot a sandwich chimney is, and whether it can cause a fire. (I apologize for the introduction, after the experiment the camera was overheated and out of focus.)

How to assemble a sandwich chimney

To assemble with their own hands chimney technically not difficult. Structurally the device consists of individual elements. metal pipes of smaller and larger diameter with an inner insulating layer.

Assemble the structure as follows:

  • The size of one element is standard. 100 cm in length. One piece of a smaller diameter is inserted into the other piece of a larger diameter. The connection is made from below from the heater, moving upwards.
  • An adapter or a reducer pipe of up to 50 cm in length is attached to the heater. If the flue pipe will be led through the wall, then in addition in a horizontal position set the outlet at an inclination of 3 degrees.
  • The first element of the flue pipe connect to the adapter or adapter to the stove. After that the tubes are inserted into each other.

Important! During installation, attention should be paid to the fact that one end of the element is narrowed to ensure convenient insertion into the next. All elements are assembled so that the condensate formed during the operation of the chimney drains into the lower part of the structure.

  • Perform the joining of two elements to ensure complete sealing of the device.
  • All joints are carefully sealed with couplings, parallel install clamps, which provide a reliable attachment of the finished system to the wall surface. To prevent possible shifts of the structure, set the supporting brackets for every 1.5 meters of the pipe.

There are two options for installing a chimney system for the bath: inside the building with a conclusion through the roof or outside with a fixation to the wall.

Fire safety requirements for chimneys

Fire safety rules apply to all types of pipes for smoke exhaust (ceramic, brick, asbestos cement or metal).

Incorrect connection can cause a fire. This is most dangerous in wood frame houses.

It is important to note that, depending on what device is used for heating, requirements for fixing the chimney are different. This is due to the different temperature of the raw material for combustion:

  • Natural gas condensing appliances have a working temperature of 80 degrees, and the limit is 120 degrees.
  • In the gas atmospheric working. 120 degrees, the limit. 200 degrees.
  • Bath stoves can reach temperatures of up to 700 degrees.
  • Burzhuyki, fireplace device. from 350 to 650 degrees.
  • In diesel units, the index is 250 degrees.
  • For solid fuel boilers on wood. 300 degrees. For coal. up to 700 degrees.

It is noted that the smoke temperature at the outlet of the gas boiler is low, due to the significant efficiency (efficiency factor). from 88 to 96%. But it produces condensate that needs to be drained.

The most flammable are considered pipelines in furnaces, boilers on the To learn more about the requirements and norms of the current SNiP regarding chimneys you can here:

In turbo, condensing devices must be made coaxial chimney. This implies double protection when the chimney in the chimney goes. Sectional sandwich structures may not be used.

Technical characteristics of pipes

These are important parameters when selecting elements for specific installation conditions. Safety, longevity of operation depend on correct determination of necessary details.


Most manufacturers of boilers and other heating devices in the manual of operation prescribe the optimum diameter of the chimney. This parameter depends on both the height of the fixture and the strength of the draught.

When the room has to make the transition from masonry to sandwich modules, the calculation of the diameter is as follows:

  • In a fireplace for 1 kW of power goes 8 kv. cross-sectional areas.
  • In wood burning stoves with power up to 3.5 kW 0.02 Kv. m of section equals 160 mm of diameter.
  • If the capacity of the furnace is higher than 5.2 kW, the diameter is increased to 190 mm.
  • If the output is up to 7 kW per 0.038 sq. m goes 220 mm diameter.

It is forbidden for the chimney diameter to be less than the diameter of the stove spigot.

wall thickness

In gas appliances is determined by the diameter of the product:

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In solid fuel boilers, the main factor influencing the choice of wall thickness is the temperature of combustion of raw materials.

It is important to note that in such boilers there must be the uninsulated part of the pipeline to be connected to the outlet pipe. It is made from a piece of heat-resistant stainless steel. Thickness of the walls. 0,8-1 mm.

Outside casing chimney with a diameter of 450 mm is taken with a wall thickness of 0.5 mm, with more than 500 mm. 0.6 mm.


The height of the chimney relative to the ridge is determined on the basis of three parameters:

  • The height of the sandwich pipe must be at least 5 m.
  • If the roof deck is made of flammable material, the pipe is made higher than the ridge at 1-1,5 m.
  • On the roof made of non-flammable material (corrugated sheet metal) you can install it on the height of 0.5 m from the ridge. The same applies to flat roofs.
  • On pitched roofs, when the chimney is located at a distance of 1.5 m from the ridge, the height is 0.5 m or more.

If the chimney is at a distance of 3 m from ridge level, the height is determined by running the trimmer line at an angle of 10 degrees with respect to the horizon.

The material

To assemble a reliable chimney, use 3 main types of raw materials.


The classic option is red refractory. Perfectly withstands high temperatures up to 1000 degrees. Has a good heat output. The masonry technology is complicated, so without experience to create such a design by yourself will not work. The process is time consuming. Requires the pouring of the foundation, which should be planned even at the design stage. It is recommended to put a sleeve of stainless steel sheet inside, otherwise the brick will be absorbed by condensation and over time the inside of the walls will begin to flake, and the outside will form stains. Construction will be expensive.


Chimneys are durable, resistant to changes, high temperatures.

Manufacturers can supply ceramics with these assembly options:

  • Ceramo Stainless. The casing is made of stainless steel 0.8 mm thick, so outwardly the tube is indistinguishable from a metal one.
  • Ceramic-ceramic. The trim of the product is made of expanded clay blocks. Reminds of brickwork.
  • Clay and stainless steel. Combination of the two previous types.

Ceramic surface is smooth, so soot and ash are deposited on the walls to a minimum.

Stainless steel

Modular type. Optimal variant of steel alloy. AISI 430 BA. Features heat resistance, chemical and environmental resistance.

Single-walled can be mounted inside the house.

Sandwich pipe. the best in the street, because it has a layer of insulation, minimizes the accumulation of condensation inside the pipe, prolonging the life of the metal parts.

How to properly install a chimney with their own hands: all the nuances when installing a chimney

In your private home or bath in the presence of a heating boiler, fireplace or stove is very important to correctly select the method of disposal of combustion products. And the main one is smoke. If you approach the issue inattentively, you can not only reduce the efficiency of functional operation, but also put your life at risk. Carbon monoxide, if it spreads inside the room, even in small quantities, can cause serious poisoning. Proper installation and chimney flue installation with their own hands. it is a task today available not only to professionals, but also to amateurs who have studied in detail the technical side of the issue.

Rules of arrangement

Carbon monoxide is almost impossible to identify, it has no taste and smell, it is invisible visually. And it is heavier than air, so it settles and remains in the room. In this regard, it is necessary to follow the basic rules for the installation of the heat generator and chimney:

  • When installing a stove or fireplace with a large mass, prepare in advance under them the foundation: a small platform, which will not move out of place if the base of the structure sags.
  • Wall and ceiling ceilings, if they are made of combustible materials should be located at a considerable distance from the source of fire (about 40 cm). When passing the wall and ceiling ceilings: 500 mm. to combustible, 380 mm. to non-combustible.
  • Observe the minimum number of bends in the chimney. Do not allow right angles in the system, it is better to divide such a bend into two sections or use elements with a smaller and larger angle.

There are standards for installation work, depending on the type of fuel used. This SNIP 41-01-2003, NPB 252-98 and VDPO. Ignoring them can cause many irregularities that affect the quality of the heat generator. Improper selection of the device can lead to overheating of the slabs, insufficient draft leads to soot deposits, and leaky assembly leads to smoke in the room.

The main technical characteristics of the chimney

As a rule, the manufacturers of heat generating devices in the instructions prescribe the recommended diameter of the chimney. This parameter is directly dependent on the strength of the draught. And it is already determined by the height, the dependence is directly proportional. The main requirement: the diameter can not be narrower than the diameter of the tube of the furnace, it is forbidden.

Calculation of the height of the chimney relative to the ridge is based on the requirements of SNiP 41-01-2003 and SP (Building Regulations) 7.13130.2009, as well as the recommendations of the manufacturer of the heating device.

If the roof is flat, the height above the roof is at least 50 cm. On pitched roofs, in the case of the location of the chimney at a distance from the ridge to 1.5 m, its height must be at least 50 cm relative to the last or fencing parapet. If it is located within 1.5-3 meters. the height can not be below the ridge or parapet. When the structure is further than 3 meters from the ridge line, its minimum height is determined by drawing a line at an angle of 10 degrees relative to the horizon.

Today, the consumer has many options when choosing a smoke extraction system:

  • The classic option of pipes laid out of brick,
  • Ceramic analogues,
  • Modular stainless steel chimneys, which have become popular relatively recently, but have already established themselves as a simple and yet reliable device.

How to properly install the chimney. choose the type of output

There are two options for the passage of the chimney:

  • Through the wall. The advantages of this solution is to improve fire safety, minimize smoke, the possibility of simply increasing the draft depending on the height of the pipe, as well as installation in the finished building. But there are also disadvantages: more complicated and expensive installation.
  • Through the roof. The advantages of this solution. high stability of the structure, no supercooling of flue gases. But at the same time the probability of “missed” the appearance of fire is higher, since the smoke occurs in the ceiling, which is in the attic and the roof, and they are not visible up to the appearance of fire.
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Be sure to follow the requirements of SPiP 41-01-2003 “Heating, Ventilation and Air Conditioning:

  • The cross-sectional area of the flue pipe must be at least the cross-sectional area of the boiler spigot. Chimney ducts must be vertical, without ledges.
  • There must be a vacuum at the inlet of at least 5 Pa. The recommended height of the duct is at least 5 m from the air intake of the boiler.
  • It is obligatory to use UPE at the intersection of the roof or wall.
  • No horizontal cleaning channels in the attic space.
  • Joints of the parts cannot be mounted in the interfloor and attic ceilings.
  • The flue pipe must not touch any utilities.
  • The heating of the nearest building elements should not exceed 50 degrees.
  • It is not recommended to use a sandwich chimney as the first element installed directly on the outlet pipe of a heat generating unit. The first item must be the adapter.
  • Installation is from the bottom up, each successive element goes into the previous one.

How to assemble a sandwich: by smoke or condensate

An important point. it is the choice of how to assemble the chimney. This is especially true when it comes to installation of industrial chimneys.

So, there are two basic types. assembly by condensate or smoke. We unequivocally recommend the assembly by condensation: each successive pipe is inserted into the previous one. Do not forget that the installation of the chimney runs from the bottom of the heat generator upwards.

When building on the condensate moisture flows down the inner wall, not deposited on the pipe, soot accumulating and corroding the walls. Also an important point when assembling on the condensate is that the moisture does not get into the insulating layer of the sandwich chimney, thus not destroying it. The service life of stainless steel pipes is thus increased.

Rules of installation of flue ducts

When installing a sandwich-type chimney, you must follow the general rules of fire safety, which apply to any type of chimney. ceramic, asbestos, brick. Improper piping is fraught with the risk of fire, especially in wooden cottages. frame, log, timber.

Recall the design of the modular sandwich. Straight sections and shaped pieces made of stainless steel pipe 0.A condensation of 5 1 mm thick wrapped with a layer of non-flammable insulation (kaolin or basalt wool 25 100 mm thick). Zinc-coated or stainless steel protective sleeve on the outside 0.5 mm.

Requirements for the chimney device slightly differ depending on the type of heating equipment. The reason. different temperature of combustion products at the output of heat generators:

  • Atmospheric gas boiler. a maximum of 200 ° C, the working. about 120 degrees;
  • natural gas condensing heaters. 120 and 80 °C respectively;
  • solid fuel boilers on firewood, pellets. up to 300 degrees, on coal. 500 700 ° C (maximum);
  • fireplaces and stoves. 350650 °C;
  • sauna stoves. up to 700 °C;
  • Liquid fuel (diesel) units. 250 °C.

Smoke temperature at the outlet of diesel and gas heat generators is low due to high efficiency of 88 96%. But it produces a lot of condensate, which must be drained. Pipes of wood boilers and furnaces are more fire-hazardous, because they are heated more strongly clogged with soot.

Note. Drainage of gases from condensing and turbine units is organized through the coaxial chimney. a double duct “pipe-in-pipe”. Modular sandwich is not applicable.

Chimney flues of gas and diesel boilers

Installation of sandwich chimney for gas-fired heating units should be carried out according to these rules:

  • The minimum height of the tube. 5 m, the optimum. 6 m. Count up from the working surface of the burner.
  • The flue header must not get into the zone of wind support, which is formed near the ridge of a gable roof or a tall building standing nearby. To make the natural draught work well, mount the chimney according to the diagram given.
  • The diameter of the inner passage of the sandwich is chosen according to the size of the outlet pipe of the boiler. It is unacceptable to install a flue pipe with a smaller cross-section.
  • The maximum length of the horizontal section connecting the heat generator with a vertical trunk of a sandwich flue. 3 m;
  • Allowed number of 90° bends of the pipeline. 3.
  • The vertical duct may bend around the load-bearing structures of the roof. rafters, beams, when installed outside. roof overhangs. The maximum deviation. 1 m to the side, the angle of rotation of the sandwich. 30 or 45 °.
  • At the bottom of the vertical section provides a for condensate collection and drainage.

Important! Chimney pipes of gas heaters may not be covered by all sorts of umbrellas, deflectors and other nozzles.

A separate issue. the passage through a wall or floor made of combustible materials. Fire protection requirements are as follows: the distance from the inner wall of the sandwich pipe to the nearest wooden structure must be at least 38 cm. Access openings must be made with due consideration of the specified clearance.

Requirements for chimney pipes

Chimneys of furnaces, fireplaces and solid fuel boilers are heated to a higher temperature. Soot is deposited inside, and condensation occurs when stoking with damp wood. The latter mixes with sediment and forms a sticky, hard plaque that is difficult to scrape off.

Synopsis. The sandwich briefly withstands overheating up to 1000 °C. Since the operating temperature of basalt insulation is 600 750 degrees, frequent accidents cause destruction of mineral wool. Stainless steel inner sleeve deforms too, sometimes bursting at the seam.

Rules for sandwiching from a wood stove, TT boiler:

  • The above requirements for chimney stack height, chimney diameter and number of turns remain valid.
  • The horizontal connecting part is done as short as possible, it is desirable to settle in 40 cm. It is there where a lot of soot accumulates, so it is important to have a cleaning option.
  • Condensate depth of 250 mm is needed for solid fuel boilers and metal heating furnaces. It also serves as a revision hatch. Exception: heaters with high gas temperatures in saunas and fireplaces connected directly to the vertical chimney.
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Important point. Gaps in the chimney-pieces must be filled with noncombustible insulating material, such as basalt cardboard, rock or kaolin wool. Pipeline connection at the intersection of the floor must not be done.

Some manufacturers (the same Schiedel) write in the installation instructions that the distance from the outer wall of the sandwich pipe to the combustible structure of the ceiling or wall must be 20 cm. The indication does not follow generally accepted rules, but in your own home, you are the only one responsible for the consequences. Incorrect installation, poor-quality sandwich, soot deposits. all these factors can lead to a fire.

If it is necessary to arrange a transition from a brick chimney to a sandwich chimney inside the house, its diameter is selected as follows:

  • fireplace. 8 cm² section for each kilowatt of heat output;
  • Wood-fired stove with a heat output of up to 3.5 kW. 0.02 m² = Ø160 mm;
  • Same, up to 5.2 kW. 0.028 m² = Ø190 mm;
  • 5 watt-hour stove.27 kW. 0.038 m² = Ø220 mm.

The distance from the top of the connecting sandwich to the wooden ceiling. at least 50 cm, protected by a sheet of metal basalt cardboard. 40 cm. In brick houses with concrete ceilings indents and partitions are not necessary.

Installing the chimney with your own hands: how to do it right?

Metal chimneys are of two kinds: more modern sandwich pipes and standard single-wall.

  • The diameter is the same up to 5 2 kW. 0;. The diameter is the same up to 5 2 kW. 0;
  • A layer of non-combustible insulation, usually basalt wool;
  • external cladding, which protects the insulation from getting wet.

This design greatly reduces the amount of condensation because the exhaust gases have no contact with the cold outer contour of the tube. In addition, because of the thermal insulation, the risk of burns from accidentally touching the chimney is small. Because of the same, the minimum allowable distance between the inner wall of the chimney and the combustible materials lining or building envelope is much lower than that of single-wall chimneys.

Single-walled chimneys are simple pipes of thin steel. Their only significant advantage over sandwich pipes. price. It is because of the low cost such chimneys still hold a leading position. Therefore, in our instructions for installing the chimney with their own hands, we will describe the installation of two types of pipes at once.

Installation of the chimney from the sandwich pipes with their own hands: step by step instructions

Proper installation of the chimney always begins from the furnace, boiler or other heating device. Thus it is necessary to work with pipes in dense gloves from a cotton cloth. Without them you can cut your hands with the thin walls of the pipe.

Before you put a chimney, you need to draw a diagram of it to correctly calculate the number of elements required and their types. This is especially important if the chimney channel must follow a complex path or will not pass through the roof, but through the wall.

The first to install the adapter to the chimney outlet of the heating device. This can be a firm transitional element or just a single chimney pipe with a fixed adapter. Since the first element of the chimney is mounted in close proximity to the furnace, starting with a sandwich pipe is categorically impossible. This can lead to the melting even heat-resistant insulation, which at least worsens the draft. The worst result of such installation. the fire.

All joints between each element of the chimney should be thoroughly covered with heat-resistant sealant. It is desirable that its operating temperature was equal or higher than 1000 °C. This will keep the tube from air leakage, because there are almost always gaps invisible to the eye, even if the segments are tightly fitted to each other.

The second is placed the slide, which can be used to close the chimney if necessary. Behind the chimney shutter installed starter sandwich pipe, which differs from the usual segments of the closed lower part.

Next, you need to properly assemble the chimney: “by condensation”, tightly inserting the sections into each other, if necessary. using clamps. Every two meters of the chimney using clamps attached to the wall or other enclosing structures.

For passages through walls and ceilings on the way to the chimney mounted ducts. This is a section with an external loop of steel and thermal insulating jacket, which is made of asbestos or mineralite. Place basalt wool inside the casing, which is separated from the chimney with basalt cardboard.

When passing through the roof is important to trace that between the pipe and the rafters, as well as other combustible elements was not less than 250 mm at any point of the circumference. To protect the insulation from the vapor using either special foil materials, or just a steel apron with the mandatory sealing of the contour.

Features of installation of a single-wall chimney compared to the installation of sandwich pipes

Although the principles of installation of sandwich pipes and single-walled chimney are similar, there are several significant differences:

  • Many manufacturers recommend that during the passage of the pipe through the walls, floors and roofs to leave at least 600 mm to combustible materials. This is even more than the regulations.
  • Pipes that run inside residential and common areas need at least insulation, and better. in the lining. Otherwise, accidental contact with the chimney during the operation of the heater will inevitably lead to a serious burn. the walls of the furnace pipe can be heated to 400 ° C and more.
  • Part of the chimney outside the heated space, you also need to insulate, since the rapid cooling of exhaust gases in the tube leads to increased formation of condensation. This is especially critical for the roof, as a large amount of condensation can lead to depressurization of the pipe passage through the roof covering.

One more nuance: single-walled chimneys are quickly covered with soot from the inside. Therefore, in difficult areas is better to install the segment-revision, with which you can assess the status of the chimney and, if necessary, to clean it.

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