TOP 5 materials for chimneys, or Which chimney to choose

Contents

1. What to consider when choosing a material for the chimney?
2. №1.Brick chimney pipe
3. №2.
4. No. 3 steel chimney. Ceramic chimney pipe
5. №4.
6. No. 5 Asbestos-Cement Chimney. Vermiculite pipes for chimney
7. Other options

The primary function of the chimney is the removal of combustion products from the furnace to the outside, but one should not underestimate its role in the process of burning fuel and forming thrust. Experts say that with the right choice of material for the chimney pipe and proper installation of it, the heat transfer from the stove or boiler can be increased to 10-15%.However, for a gas or solid fuel boiler, fireplace and stove you need a chimney not only of different heights and diameters, but also of material. If earlier it was chosen only between a brick and a non-galvanized metal, then today the range of suitable options is much wider. We understand what materials for the chimney, more precisely chimney pipes, exist, for what conditions they are intended, and what chimney to choose depending on the type of fuel used.

What to consider when choosing a material for the chimney?

Chimney is a complex structure consisting of an vertical pipe, an umbrella to protect against precipitation, a viewing window for maintenance, a condensate collection tray and other elements. The vertical pipe is considered to be the main part of the chimney, and the safety and efficiency of the furnace or boiler operation depends on it.

In order to choose the right chimney material, it is necessary to clearly understand what kind of fuel will use: natural gas, diesel, coal, firewood, peat or sawdust. Each of them has a different temperature of combustion, temperature and composition of the exhaust gases. Therefore, when selecting the material for the chimney, the following parameters are taken into account: :

• flue gas temperature .Naturally, the material must withstand somewhat higher temperatures than those characteristic of the outgoing gases;
  

  Approximate flue gas temperature( * fuel with high sulfur content)

• corrosion resistance .During the combustion of certain types of fumes, sulfuric and hydrochloric acid vapors are formed, which not every material can withstand. The more sulfur in the fuel composition, the more resistant to the effects of sulfur compounds should be the material. According to this parameter, chimneys are divided into three classes: the first for exhaust gas combustion products, the second for firewood and liquid fuels with sulfur content up to 0.2%, the third for coal, peat, diesel fuel;
• condensate in the chimney;
• gas pressure in the chimney .There are designs designed to work under natural pressure, and there are those that are designed to work with boilers with supercharging;
• resistance to soot ignition .The temperature in the chimney at the ignition of soot, if it is present, can rise briefly to 10000С - not every material can withstand it.

From all this it follows that:

• for wood-burning stoves, solid fuel boilers, bath stoves and fireplaces you need to choose a material that can withstand an operating temperature of about 7000С and a short-term increase to 10000С.These are brick and less often ceramic chimneys;
• for gas boilers requires a chimney that can withstand temperatures of 2000 ° C with a short-term increase to 4000 ° C.Usually, metal pipes are used for this purpose;
• for oil-fired boilers and sawdust requires a material for the chimney pipe that would calmly withstand temperatures up to 2500 ° C with rising to 4000 ° C, and if we are talking about diesel fuel, then it is resistant to the aggressive environment of exhaust gases.

Now let's look at the properties of the most popular materials used for arranging the chimney pipe.

№1.Brick chimney pipe

Chimney brick used for a long time, and it has already become traditional material. Today it can not be called universal, which, however, does not reduce its popularity. The brick chimney is arranged inside the walls of the building; those areas that pass through unheated rooms or outside the building are carefully insulated so that the flue gases inside are not cooled. For the construction of such a chimney, a full-bodied red brick of grade not lower than M150 is suitable; for its masonry, lime or lime-cement mortar is used.

The main advantages of brick pipes for a chimney are their durability and excellent heat resistance( ceramic bricks withstand temperatures up to 8000С), and they look great on the outside, and they have almost no equal in fire safety. A brick chimney fits for stoves and fireplaces with wood , and when working with boilers for liquid fuel, gas, pellet and solid fuel pyrolysis boilers quickly destroyed. The thing is that these boilers are designed in such a way that the exhaust gases have a low temperature. They quickly condense and settle on the walls of the pipe, due to which the latter are constantly moistened. Considering the fact that aggressive chemicals are contained in the waste gas, including sulfuric acid, the brick quickly collapses. The results of such exposure appear wet spots on the outer surface of the pipe.

True, there is always a way out. To connect a modern gas-fired or gas-fired boiler to a brick chimney pipe, an steel or ceramic pipe is installed in the , which has slightly different performance characteristics.

Since the surface of the brick is rough, soot settles well on it, which gradually leads to a decrease in thrust. Brick pipe cleaning and repair is not an easy task. In addition, a large weight of the structure will necessarily require a foundation. On the other hand, it is difficult to find a worthy counterpart for arranging a chimney stove or fireplace.

№2.

steel pipe chimney For gas and solid fuel boilers , steel pipes are best suited, but it should be stainless, heat-resistant and acid-resistant , since sulfur particles that are present in virtually every type of fuel in one or another quantitywhen combined with moisture and coal particles form an aggressive environment. Stainless steel is capable of to withstand temperatures up to 5000С , pipes with a wall thickness of 0.6 mm are used for arranging chimneys, but for solid fuel boilers it is better to use steel with a thickness of 1 mm. Steel pipes are a whole system of straight sections and various shaped elements, incl.adapters, elbows, tees, etc. Such a system can be mounted independently or be built into an existing brick channel.

The main advantages of steel pipes:

• simplicity and high speed of installation, because the weight of the structure is small, there is no need for a foundation, and of the finished elements, not even the biggest professional will assemble the entire system without problems;
• repair work is easy;
• soot particles do not accumulate on smooth walls, their surface is easy to clean, so we can speak about consistently high aerodynamic characteristics for the passage of exhaust gases;
• high corrosion resistance;
• the ability to create complex structures;
• high tightness, due to which you can create a forced exhaust.

Among the minuses of is called high cost, especially when compared with brick or ceramic counterpart, but if simplicity and speed of arrangement, low weight and resistance to aggressive media are important, then the choice is better to stop on a steel chimney. The disadvantages are sometimes low heat resistance, but for modern boilers with a slow burning system, they are more heat-resistant and unnecessary.

Depending on the characteristics of the room, boiler and climate, use one of the following types of steel chimneys:

• single wall steel pipe consisting of one layer of stainless steel. This is the easiest and cheapest option, they lay such a chimney in a specially laid out vertical channel. Often, such chimneys are arranged in a bath, and the waste heat from a steel pipe is used to heat water;
• single-walled steel pipes for the reconstruction of the brick chimney can be oval-shaped. Such a restoration process and the adaptation of an existing chimney for working with a gas boiler are called “liners”;
• double-skinned sandwich panels , consisting of two steel pipes, in the space between which is placed a layer of insulation( basalt wool).The use of the latter makes it possible to prevent the formation of condensate inside the pipe, while its external surface is almost not heated. Simplicity of assembly and excellent operational qualities allow using such systems both indoors and outside on the wall;
• coaxial flues from steel also consist of two pipes placed one in another, only there is no insulation between them, and the resulting space is intended to supply air to the boiler to sustain combustion. Combustion products are discharged through the internal pipe. Such chimneys do not behave very well in the harsh domestic winters. Cold external air passing through the external pipe can sometimes cool the internal pipe and the gases passing through it. This leads to a sharp condensate and freezing it on the surface of the pipe. The chimney is gradually clogged, and the automation, in response to this, turns off the boiler, so in this case it is better to equip the chimneys with two separate pipes.

It is worth noting that sometimes for the arrangement of the chimney use thick pipes of low-alloy steel - this option is usually found in sauna stoves. Also craftsmen sometimes use cast-iron sewer pipes for the same purpose.

# 3.Ceramic chimney pipe

Ceramic chimney pipes are considered the most versatile, and among them main advantages:

• durability;
• resistance to aggressive environments and corrosion;
• on the inner smooth surface does not linger soot, making it easier to care for the pipe;
• high heat absorbing characteristics;
• resistance to high temperatures. For solid fuel boilers use ceramic pipes that can withstand up to 6500C and are resistant to a sharp increase in temperature when soot ignites. For gas boilers, you can use pipes that can withstand up to 4500С, designed to work in the wet state and have condensate traps.

For the installation of a ceramic chimney requires the installation of a separate channel. The shell is equipped with special concrete blocks with voids. A layer of mineral wool insulation is placed around the pipe in order to protect adjacent structures from excessive heat and reduce the formation of condensate. Both the pipe and the heat insulation are capable of absorbing water, so they need to ensure normal ventilation. It is created due to the presence of vertical air channels between the insulation and concrete blocks. By the way, in concrete blocks there are also channels for placing reinforcement in them. Be sure to reinforce should the part of the chimney that goes out.

In order to expand the scope of use of ceramic chimneys, they are produced in the steel case , and also in the form of rectangular section elements .The first ones do not require the arrangement of the foundation and the creation of special channels, the second can be used for the reconstruction of brick chimneys.

№4.Chimney from asbestos-cement pipes

A couple of decades ago, asbestos-cement pipes were everywhere used for arranging chimneys. Actually, initially they were not designed for such purposes, as is easily seen when studying their performance. From the advantages of the material, only its low price is , but has 's disadvantages more:

• material withstands temperatures up to 3000 ° C, and often this is not enough. Such a pipe can only be used at the maximum distance from the firebox, where the smoke passes by already cooled;
• on a rough surface quickly accumulates soot, which tends to ignite. But if a brick chimney with such a cope easily, the chimney from the asbestos-cement pipe can just explode;
• instability in front of condensate, which contains harsh chemicals. Moreover, the condensate is able to be absorbed into the pipe, destroying it and impairing the appearance;
• heavy weight and complex installation;
• leakage of joints.

It is possible to use an asbestos-cement pipe for a chimney only with the certainty that the installation will be carried out correctly, as well as under the condition of regular cleaning of the chimney, but it is better to pay attention in the direction of other options.

№5.Vermiculite chimney pipes

Not so long ago, vermiculite chimney pipes appeared on the market. These are stainless steel pipes, which are covered inside with a layer of vermiculite mineral 5 cm thick. This mineral has low thermal conductivity, therefore, in essence, it is a natural heat insulator. Moreover, vermiculite is absolutely inert to aggressive combustion products.

Among other advantages of the , the vermiculite pipes have high durability, relative ease of installation, and no need for chimney heat insulation. The main deficiency of is the ability to accumulate soot, so it will often have to be cleaned.

Other options

At the moment there are other ways to equip the chimney:

• glass pipes a few years ago would cause confusion, but today their advantages are indisputable. Glass does not accumulate soot and soot, is easy to clean, inert to aggressive media and withstands high temperatures. But the glass chimney is expensive, it is difficult to equip it, additional insulation is required, and the sealing of the joints is complicated, therefore, so far this extravagant method has not gained distribution;
• polymer pipes - another new product. Produce them from the composite, which, according to the stated qualities, has a long service life, but can only be used at a temperature of waste gases not more than 2500 ° C, i.e.its scope of application is limited to gas columns and boilers;
• concrete blocks and self-poured concrete chimneys in some sources are called an alternative to brick pipes. Professionals strongly criticize this option and recommend not playing with fire: concrete will not withstand severe temperature loads, and it is impossible to make a heat-resistant compound at home.

Finally, we note that before choosing the material for the chimney, you must choose a boiler or decide on the design of the furnace. In addition, it is necessary to take into account the design features of the building, and best of all, even before the construction of the house begins, consider all the nuances of its future heating. Calculations of the chimney channel for their safety is better to trust a specialist.