Stainless steel chimney dia. Chimney from sandwich pipes: calculation and installation
The term "sandwich" was coined in 1762. So called closed sandwiches in honor of Earl John Sandwich. Nowadays, this term is used in structural materials as a designation for multilayer composite structures. The advantages of a composite of several layers are well known, these are increased structural strength, the ability to use a soft or fragile material as a core, such as insulation, for example. The use of sandwich structures in construction is diverse. It is worth considering another application of a multilayer device - a sandwich pipe for chimneys. More details in our material.
A chimney is a necessary element of a heating system that works by burning fuel, it ensures the removal of fuel combustion waste: carbon monoxide and smoke. Working conditions can hardly be called easy. Due to the fact that the height of the chimney reaches large dimensions, the material must withstand high vertical loads, work when exposed to an open flame and high temperatures also makes its own demands. In addition, the material must withstand constant fluctuations in temperature outside the surface of the pipe and inside it.
The surface inside the pipe must be smooth and allow the chimney to be cleaned, since during combustion, in addition to gaseous products, soot and soot are formed, which settle on inner surface chimney, obstructing the chimney and threatening fire and subsequent fire.
All requirements for chimneys are met by sandwich pipes for a chimney. These pipes consist of an internal channel made of stainless, heat-resistant steel, covered with a layer of mineral insulation. A protective sheath is installed on top of the insulation, made of stainless or galvanized steel or sheet metal coated with a protective powder coating.
The connecting seam of the outer shell can be welded by means of automatic welding or sealed with a seam seam.
For the manufacture of the inner tube, stainless alloy steels of the following grades are used:
- AISI430, relatively inexpensive stainless steel, normally withstands temperature fluctuations. Fastening most often with a seam seam, since this metal is poorly welded;
- AISI439, steel alloyed with titanium, which made it possible to achieve increased heat resistance, has good anti-corrosion characteristics;
- AISI316, nickel-molybdenum alloy steel of increased heat resistance, recommended for oil-fired boilers and gas heaters;
- AISI304, a close inexpensive analogue of 416;
- AISI321, the most demanded heat-resistant alloy steel, has excellent anti-corrosion and heat-resistant characteristics;
- AISI106S, a relatively rare heat-resistant alloy, extremely high performance heat resistance, practically does not give in to corrosion. It is used for expensive products operating at high thermal loads.
It should be noted that both galvanized carbon steels and inexpensive alloyed steels are used for the outer shell, the second option is more resistant to external factors, but at the same time, the cost of products with its use is quite high.
As a heater for sandwich pipes, mineral, non-combustible heaters such as mineral wool or basalt are usually used.
To connect the pipe modules to each other, one end of the pipe or fitting has a bell, on the other side there is a corrugated narrowed area, which serves to wedging in the bell and creating a reliable connection impervious to gas and smoke.
Sandwich pipes for chimneys - a luxury or a panacea?
The traditional materials for the chimney were masonry, metal, ceramic and modern sandwich stove chimney. The disadvantages of such chimneys are known, but it is worth comparing the advantages and disadvantages of various chimney systems:
- Brick chimney. The reliability and functionality of such a design depends entirely on its weight. Therefore, a reinforced foundation for the furnace is needed. A brick chimney is heavy, which affects its foundation, and also requires large investments in construction and maintenance. The construction of a brick pipe is a laborious and complex process. Bricks crumble and deform from the effects of temperature changes; over time, brickwork requires repair. Maintenance of such a pipe is also complicated, due to irregularities on the inner surface of the chimney, soot and soot begin to accumulate there, which must be periodically cleaned;
- Steel pipe, as a furnace. Again, due to the high temperature loads on the wall, its sufficient thickness is required, and the thicker the wall, the heavier the product itself. In addition, steel, under the influence of temperature, can burn out, and condensate on its surface can lead to metal corrosion, and subsequent failure of the pipe. The installation of such a chimney is also complicated, requiring either the use of a one-piece product or the use of special connection methods such as welding. The advantage of such a chimney device is its price;
- Ceramic pipes, clay mixture products, subjected to heat treatment, has high heat-resistant characteristics, is quite well mounted. Durable. The disadvantage is high weight and, compared with metal, low strength characteristics.
- Chimney sandwich. Lightweight construction consisting of separate, easily connected modules. Installation does not require special equipment and experience. The design can be displayed in any direction, including in a horizontal or inclined position. It should be noted the simplicity of the device: fasteners and individual modules. The chimney sandwich consists of three layers: an inner channel made of heat-resistant steel, a layer of insulation and an outer, protective pipe. The chimney itself is quite light, so fixing it will not cause any special problems. The inner surface of the pipe is smooth, made of heat-resistant alloy steel, which greatly facilitates its cleaning. The insulation will protect the steel from condensation and corrosion. The outer, protective shell serves to protect the insulation from the effects of the external environment.
It is clear that chimneys and chimneys of a sandwich construction are slightly more expensive than ordinary steel ones, but during the service life (which is 25 years), all the costs of the composite will fully pay off, since, unlike steel, these chimneys do not burn through and do not rust.
Reviews of sandwich pipes for the chimney are also sustained in a positive way. Users appreciated the ease of installation of the structure, its durability and appearance.
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From this review you will learn: varieties, average prices and design features; rules, requirements for work and features of the installation of the chimney, recommendations of specialists.
Dimensions of sandwich pipe modules
A sandwich pipe for chimneys with a diameter of 115-120 mm is considered the main one for a small country house or cottages. The heating system in such houses rarely exceeds 3.5 kW. For systems of higher power (from 5 kW), pipes with diameters of 180 mm are used, for heating systems with a power of over 7 kW use pipes with a diameter of 220 mm or more. The range of sizes of the sandwich pipe for chimneys is wide and you can quickly and easily select the required diameter according to the norms of SNiP.
When calculating the diameter of a sandwich, one should not forget about other elements of the chimney: fasteners, clamps, start-sandwich, slide damper module, transitions through ceilings or walls.
But, not only the diameter of the sandwich pipe for the chimney matters, the height of the module is no less important. It is necessary to calculate the length of the chimney, taking into account the exit of the pipe above the ridge of the house to a height of up to 1.5 meters, the height of the exit of the pipe depends on a number of factors and it must be selected individually, but on average the length of the exit is 0.5-1 meter above the roof ridge. Sandwich pipe modules are supplied in several versions, common: 0.25, 0.5 and 1 meter high.
Calculator for calculating the minimum diameter of a sandwich chimney for solid fuel stoves
A sandwich chimney pipe removes combustion products in a fireplace, stove or boiler, creates draft and ensures fire safety. Its installation does not take too much time and is made taking into account the characteristics of the room.
Two pipes nested one inside the other and having a heat-insulating layer in the middle are called a sandwich pipe. A special place is occupied by pipes made of heat-resistant stainless steel, they are less prone to clogging, easier to maintain. The heat insulator inside prevents condensation. In the form of insulation, non-combustible materials are used: basalt fiber or mineral wool. They are obtained from molten rocks, the low thermal conductivity of the material is achieved due to the high content of air in the mineral fibers.
Chimney made of sandwich pipes
Advantages and disadvantages
Among the main advantages of sandwich pipes for the chimney are the following:
- light weight;
- installation speed;
- the presence of smooth inner walls (improves traction and reduces the formation of soot);
- bypass capability truss system.
The main disadvantage: after 15-20 years, the heat-insulating layer wears out, and the boiler loses its original performance. Moreover, the more often the equipment is turned off, the faster the chimney from the sandwich pipes fails.
A cap is installed on top of the pipe - protection from atmospheric precipitation
Loss of tightness is a serious reason to replace the pipe. To prevent this from happening, purchase a quality product and trust the installation to professionals.
Device
The chimney is part of a looped system. It is through it that smoke is removed, due to which a rarefaction occurs in the furnace or in the fireplace and a portion of air is sucked in. The cycle then repeats over and over again.
A brick chimney can only be built vertically, but sometimes there are situations when, due to the characteristics of the room, it is not possible to build a strictly perpendicular structure. In this case, it is the modular system that will become best solution: with the help of transitions, elbows, tees, you can bypass a place that is inconvenient for cutting.
The inner diameter of the sandwich pipe is made of stainless steel, and the outer diameter is either made of galvanized iron or stainless steel of acid-resistant grades. Therefore, the service life of the product is long.
Boiler chimney device
When arranging a sandwich chimney, consider the following.
- The temperature of the incoming gases depends on the type of fuel used and the type of boiler. The higher it is, the more intense the pipe heats up.
- You can lead the outlet pipe from the stove, fireplace or boiler through the walls of the room. This option is used when a chimney system is being erected in an already built building. For each heat generating device, it is better to build its own smoke channel.
- If necessary, it is allowed to mount no more than two deviations from the vertical plane with an inclination angle of not more than 30 °.
- The horizontal section has a limit of 1 m.
- The total height of the chimney to the top of the pipe should be 5 m. This creates the necessary draft and ensures vacuum.
- The distance between a wooden (or other combustible surface) and the stove must be at least 50 cm.
- Incorrect assembly may cause a fire.
Modular Sandwich Pipe Size Chart
If the pipe passes through wooden floor, from the inner pipe of the "sandwich" to the wooden element, a distance of 38 cm must be maintained. The entire space between them must be filled with fireproof material - galvanized sheet. The chimney pipe must pass through the ceiling in its entirety, without joints. The chimney itself is mounted through a passage pipe - a metal box.
Variants of placement and connection of chimneys are different. It depends on the conditions of the room in which you want to install. You can install a smoke exhaust system during the construction of the house and after completion construction works. They choose a place for the chimney so that when it is installed, the integrity of the house structure (logs, truss system) is not violated.
System installation rules
The device is assembled according to the principle of the designer. The pipe must be inserted into the pipe for a length equal to at least half of its diameter. The size of the sandwich pipe for the chimney determines its throughput.
Video: installing a chimney
Connection types
There are 2 ways to connect pipes: "by smoke" and by "condensate".
- "Through the Smoke"
The pipe of the lower leg enters the inside of the upper leg of the "sandwich". In this case, the smoke moves freely upwards.
- "By Condensation"
The inner top tube is inserted into the bottom tube. And for the outer pipe, on the contrary: the lower one is placed in the upper one. The condensate moves freely downwards. This option is usually used in modern boilers running on gas. In metal, cast iron, the smoke temperature is about 300 °. Steam begins to condense at temperatures below 100°C. During the kindling, the steam turns into drops of water, which rolls down into the condensate trap.
The second method of assembly "by condensate" is more acceptable. The passage through the roof is done in the same way as the passage through the ceiling. The gap between the rafters and the pipe must be maintained at least 150 mm.
Roof cutting makes the pipe outlet airtight
Fire safety
Subject to the norms of SNiP, you can be sure of the safety of the structure under construction.
- If the chimney is installed in wooden house, use cuttings - enclosing elements made of non-combustible materials. The dimensions of the cuts are as follows: 38 cm - to the parts protected from fire, and 50 cm - to the non-protected ones.
- The building is protected with a layer of plaster of 25 mm on a metal sheet or mesh with fireproof materials (silica mats, basalt wool).
- Between wooden beams and chimneys located with them in the same wall must maintain an interval of 50 cm (if the beam is not insulated) and 38 cm (if the beam is protected by thermal insulation).
- The chimney should protrude 50 cm or more above the top of the roof.
- The scheme of the chimney from the sandwich pipes is drawn up at the design stage of the house.
Backdraft and fire are the consequences of a rash choice of a smoke exhaust system. But a modern chimney is not only durable and safe. It must withstand condensate containing acids and withstand high temperatures. flue gases. Only in this case the design will last a long time.
Any heating appliance, be it a fireplace, a boiler or a stove in a bath, requires the installation of a chimney. A lot depends on how well this element is made. This is both safety and good reliable traction in any weather and practicality with a beautiful appearance. To date, the most optimal and advanced solution for the removal of combustion products will be a sandwich pipe for a chimney. But what the sandwich pipe is made of and how the installation of chimneys of this type is carried out, we will consider below ...
Sandwich pipe device, their dimensions and diameters
Installation of a chimney from a sandwich pipe
From the name itself it is clear that "fashionable" chimneys consist of several layers, like a sandwich pie. There is an inner diameter of the pipe and an outer one. Between them is a mineral fiber. As a rule, this is basalt wool or other non-combustible mineral insulation.
External and internal sleeves of pipes are made of stainless or galvanized steel. The thickness of the metal in this case can be 0.5 or 1 mm. This, of course, affects the price of the pipe and its durability. Stainless steel in all its characteristics is much superior to galvanization, so draw your own conclusions.
AT recent times enameled sandwich chimneys became popular. Special enamel not only gives a certain aesthetic appearance, but also perfectly protects the metal from high temperatures, condensation and soot.
Modern design solutions can be quite exclusive. Today we are moving away from those stereotypes that have been around for centuries. Now you can position and remove the chimney almost anywhere: vertically, horizontally, on a slope.
One of the options for mounting a sandwich pipe
For ease of installation of such systems, the following components may be included in the package for sandwich pipes: head umbrellas, support consoles, wall mounts, various clamps, rings and ties, corners and turns, gates (latches) and tees, ceiling and roofing cuttings, starting adapters and plugs. You can list for a long time, in a word - this is a "constructor for adults" ...
Depending on the power of the installed boiler or furnace, the sizes of the sandwich pipes are different. Here we can distinguish the following standard diameters of the inner and outer pipes, respectively: 310, 300/380. All dimensions are naturally in millimeters. The usual length of one pipe element is 1 meter.
Advantages and disadvantages of sandwich chimneys
Like any design, sandwich pipes have their advantages and disadvantages. Of course, there are much more pluses and this is due to the original and practical device. As they say, everything ingenious is simple. Here are some advantages of sandwich pipes:
- Due to its design feature, sandwich chimneys have high fire safety
- Lightweight and compact design of the entire chimney. This does not require the organization of an additional foundation and, as a result, unnecessary financial costs.
- Versatile mounting options: really make any bold design decisions. Turns, bends, rounding various obstacles, this is a common thing
- Ability to lead the chimney through the ceiling or through the wall
- Due to the double circuit and insulation, little condensate forms in the pipe. The absence of moisture inside the chimney contributes to insignificant deposits of soot on the inner walls of the pipe
- Due to the smooth surface of the metal, good traction is formed in the sandwich pipe
- Simple and easy installation of chimneys
- Sandwich chimneys are virtually maintenance free. They are not subject to corrosion, have good smoke impermeability and excellent resistance to high temperatures, aggressive environments, etc.
Now about the shortcomings that still exist:
- Relatively high cost. A chimney of this type, especially with various "bells and whistles", will fly into a tidy sum
- Relatively long service life: 10-15 years. When compared with brickwork, then the sandwich pipe serves much less
- Over time, thermal expansion and contraction can cause slight depressurization of the flue duct.
Installation of sandwich pipes: highlights
All work on the installation of sandwich chimneys begins with marking and sawing 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 a must!
Installation of the "designer-chimney" begins to be carried out from the bottom up. First of all, a single-circuit pipe is installed on the furnace. Due to the absence of insulation, heat transfer is significantly increased. For example, a single-circuit sandwich pipe for a bath can be equipped with a hanging water tank. 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 segment of the chimney also enhances the heat transfer coefficient.
On the installed “single-circuit sleeve”, the so-called starter adapter is mounted. It is needed in order to reliably and beautifully connect a single-walled pipe with a sandwich. Then a gate is mounted to adjust the draft level or a double-circuit chimney immediately goes.
Such a nuance should be clarified: the assembly of sandwich pipes can be carried out in two ways (“by smoke” and “by condensate”). “Smoke” is when the top tube is inserted into the bottom one. The smoke does not encounter any obstacles. "According to condensate" - the opposite is true: the upper segment is mounted on the lower one. For an optimal result, we put on the outer sleeves of the pipes “by smoke”, and the inner ones - “by condensate”. For a better sealing effect, it is advisable to use a special heat-resistant sealant and crimp clamps.
Calculate the height of the chimney to the ceiling in such a way as to exclude the junction of the segments in the overlap area. This will increase the degree of fire safety. And now the most important moment. Many 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 deplorable. Passage ceiling box must be used. He will protect wooden structures from heat and fire. It can be covered with expanded clay, foam glass, but not with sand. It is possible to use mineral wool as a heat insulator.
When conducting a chimney through the roof, it is wise to use an element such as a flash master. This is a special sealant for roof passages, which is commonly called a "flash drive". The element is necessary and practical, you can’t do without it. A metal roof cutting element is also used here, which ensures a reliable and stable position of the chimney.
Depending on the design of the chimney, a "revision" is sometimes installed in the lower part. This sandwich pipe element is usually installed on an attached chimney that has a horizontal section. There is a small door for cleaning the smoke channel. Very convenient and right moment.
On the upper part of the chimney, spark arresters, deflectors-umbrellas are installed. Purpose: to extinguish sparks and protect the pipe from precipitation and debris.
When installing a sandwich pipe for a chimney, it is necessary to exclude their contact with various communications (electrical wiring, gas pipeline, plumbing and sewer pipes, ventilation ducts). Following the manufacturer's instructions for assembling such a "constructor", you can easily install a chimney from sandwich pipes with your own hands. This will not be difficult, although you still have to “wiggle your brains” and work with your hands.
Chimney from sandwich pipes
Very often, an improperly arranged stove chimney creates a fire hazard in a residential building. The products of fuel combustion are not completely removed from the premises and cause carbon monoxide poisoning of the body. Sometimes, due to neglect of the technological features of the work, smoke occurs and reverse thrust is obtained.
Steel chimneys and their properties
There are many varieties of materials for building a chimney in private homes. Pipes are divided depending on the purpose and functionality.
Chimney Sandwich
Insulated double-layer pipes allow the interior to heat up as quickly as possible and contribute to the effective removal of smoke from the combustion source. They are arranged 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.
Positive characteristics of a sandwich for a stove chimney
How to choose a chimney sandwich
When purchasing smoke extraction elements, it is required 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 smoke extraction with their own hands, there should be detailed instructions.
Pay attention to the stainless steel from 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 boilers solid fuel purchase products with laser welded seams and stainless steel inner tube. For boilers using gas fuel, it is allowed to connect the elements using the rolling method and the cavity inside each of the galvanization.
External elements can be made of galvanized steel, polyester, brass, stainless steel.
Sizes of stainless steel sandwiches
When buying pipes, it is required 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. Sandwich pipe should be put on the output.
Features of installing chimneys
Double-walled sandwiches solve the problem of condensation on the walls of the chimney in cold weather due to the insulation included in the design. Such isolation prevents soot formation on the inner surface and increase the service life.
To facilitate the installation of the prefabricated structure, fittings are produced for connection, channel rotation and other functions.
Varieties of elements for assembly
- The main length of the chimney is carried out in lengths of 1 and 0.5 m.
- Horizontal sections (beds) are connected using revision tees to eliminate clogging of the pipe.
- A tee for collecting condensate and cleaning the internal cavity is installed at the beginning vertical section channel. Often this happens immediately after the chimney exits to the outside of the building. One of the outlets of the tee is made opening on the thread to remove condensation moisture.
- The corners for the device for turning the chimney by 90º are made of pipe materials and are insulated with an insulator layer.
- Compensator for a smooth change 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.
- The structure of the junction with the roof is designed as a single unit and serves to form the exit of the chimney channel to the roof.
- Knot for eliminating leakage in the outlet of the roof. Installation is carried out around the chimney.
- Tip to protect the channel openings from debris, snow and dust.
How to properly assemble a chimney
outdoor assembly. The first step is a horizontal pipe section from the boiler. A steel sandwich is attached to the chimney pipe using prefabricated elements that are fastened to each other with clamps and crimped. In the middle of the distance of the horizontal section, a tee is inserted for revision.
The connection of the subsequent pipe is carried out by putting it on the previous one. You can't change the order otherwise smoke will enter the room.
The horizontal part of the pipe is lowered from the boiler by 3-5 cm so that condensate does not enter the boiler.
In the passage of the sandwich through the wall, insulation is made of non-combustible materials. If the pipe passes through a wooden wall, then it is additionally wrapped with a layer of asbestos. In brick, concrete and clay walls, it is enough to isolate the gap with mounting foam for outdoor use.
It is impossible to connect sandwich pipes at the exit point through the wall. If you accidentally hit this place, it is done pipe cutting to the passage, then a whole section of the sandwich is embedded in the wall.
After the chimney exits the wall to the street, they immediately put a tee to collect condensate, then they arrange the pipe to turn up. The sandwich is fastened to the wall by attaching it to a supporting truss, which is mounted dowels or anchors.
The chimney is assembled to a height above the roof of at least 0.5 m. The pipe is fixed every couple of meters, but sometimes the chimney is fastened more often to prevent bending and sagging of the chimney.
The elevation of the pipe above the roof directly depends on the proximity of the ridge to the chimney outlet to the surface. If the pipe rises more than 2 m, then additional mount it to the roof with a metal cable to give strength to the structure.
The device of the internal smoke channel
All connections are made in the same way as the external assembly, only special attention must be paid to the passage of the chimney through the roof.
Sometimes, for the arrangement of the place of passage, a change in the design of the roof lathing is required. Interfering bars are cut out and transferred to another place. If we talk about interfering beams and rafters, then it is not recommended to break them. In this case, the exit point of the pipe is shifted. This applies to the option when the chimney is already made in the finished building. In new buildings, such problems should not arise.
From below, a pipe is substituted for the prepared passageway, and a pipe is put on top of it. special spigot element, which is attached to roofing using self-tapping screws. The junction with the roof is treated with mastic.
The element, in turn, serves as a support for putting on the outer pipe. Along the perimeter, this entire structure is crowned with a special stainless steel skirt. The assembly is uploaded installing a chimney cap. After that, a traction test is carried out.
When installing a chimney from a sandwich pipe, it is necessary to take into account all the little things, so as not to endure trouble from smoke or carbon monoxide later. special attention should be paid for careful sealing of joints and matching pipes in diameter.
When all installation rules are followed, the chimney will serve faithfully for a long time.
