Is ceramic brick suitable for the oven. Furnace brick

This parameter determines the number of heating and cooling cycles after which the brick remains intact. Frost resistance is indicated by the letter F and a number from 15 to 100. A similar characteristic applies to bricks from which chimneys and pipes are laid. It is these structural elements that experience constant heating and cooling. Therefore, the brick must withstand large temperature differences. For cold regions, it is necessary to use material with frost resistance closer to F-75, and it is better to refrain from cheap samples with F-15 or F-25.

Thermal conductivity

This characteristic is closely related to the density of the brick. In our case, a material with a thermal conductivity in the range from 0.59 to 0.72 W / (m × ° C) is suitable.

full body

For laying the furnace, only solid bricks are used.

Characteristics

For the construction of the inside of the heating device, fireclay bricks are used, which can be of the following markings: SHAK, SHA, SHB, SHV, PB, PV and SHUS. It should soften at a temperature of 1300 degrees and above, be uniform in structure, have a high density and low porosity.

There are many requirements for fireclay bricks, since this material determines how long the furnace will last and how it will perform its functions. Therefore, the choice of brick for laying furnaces should be approached as seriously as possible.

Today, the market offers a wide range of products, but not everyone will be able to find a suitable option. Experts advise to stay on refractory fireclay semi-acid bricks. It has a reasonable price and good quality, while it has good thermal characteristics.

The main properties of various brands of fireclay bricks are shown in the table:

Characteristics	Normal performance
	SHAK	USA	SB	SHV	SUS	PB	PV
Fire resistance, °C	1730	1600	1650	1630	1580	1657	1580
Porosity, % not higher	23	24	24	24	30	24	25
Tensile strength, N / mm 2	23	20	—	20	12	20	13
Softening start temperature, °C	1320	1300

How to determine the quality of a brick

Whether the material meets the established requirements is indicated in state standards. Guided by them, you can check the compliance of each parameter with a normal value. So, GOST 5402.1-2000 allows you to establish the residual deformation of the brick after it is heated. Using the state standard 4069-69, the fire resistance of the material is checked. And according to GOST 151136-78, it will be possible to measure damage to the corners and edges of products.

However, at home it is not possible to carry out all the verification procedures provided for by the above standards. They cannot be performed without special instruments, which are available only in laboratories. Therefore, when buying a brick, you can ask for certificates of conformity, and it is also advisable to seek help from a specialist.

Furnace masters have sufficient experience to distinguish good products from poor quality. It is important to know that for the construction of the furnace, material grades from M150 to M250 should be used, and the certificate must necessarily indicate that this product is intended for furnace work.

However, even in the absence of the necessary experience, you can check the quality of the brick using the following simple techniques:

1. The product must be inspected for compliance with the established shapes and sizes. The permissible deviation of the actual parameters from those specified in the state standard is 2 mm.
2. On a large face of a brick, it is necessary to lightly hit with a hammer. If the material is of high quality, then the tool will bounce off the surface with a ringing sound.
3. After sawing or splitting a brick, you need to inspect the internal structure. In a quality product, the color should be uniform. If there are spots, this indicates internal stresses, which can later lead to the destruction of the brick when heated. In addition, there should be no chipping of the material on the cleavage surface.

Using such simple methods, you can choose a quality brick for construction work. It is important to consider that the use of materials that comply with current GOSTs will help build a stove that will become a reliable and durable heating device.

The following photos show several types of brick products.

Manufacturers

Brick "Borovichi" (Borovichi, Nizhny Novgorod region)

Red brick M250 has high frost resistance. Since 2011, it can be freely purchased on the construction markets. The material has three working surfaces. The edges of the product are rounded. Due to the optimal ratio of high quality and affordable price, the material is especially popular in the construction market.

Unfortunately, the manufacturer allows the production of not very high-quality copies. Some products differ significantly in size from the standard ones (deviations sometimes reach 1 cm). Therefore, it is recommended to order products with a margin so that you can select high-quality products that are enough for laying the furnace. We recommend that you take the help of an experienced master. Otherwise, due to non-standard sizes, it will be necessary to make too thick seams and file the building material, which will affect the appearance of the heating device.

Brick "Vitebsk Workshop 1"

The strength grade of red brick is M200. The material has a rather low frost resistance, therefore it is not suitable for laying exterior walls and use in places with high humidity. The brick has two working surfaces and sharp edges. There are no significant differences in size. It should be noted the very democratic price of Vitebsk bricks.

Today, such a product is very common in specialized outlets. This building material is excellent for laying furnace bodies, but it is not recommended to make fireboxes from it. In contact with an open flame, a brick will last only a year. Therefore, the use of this material is possible in conjunction with the fireclay type of product. Outer elements of the chimney cannot be laid from this product either.

Brick "Vitebsk Workshop 2"

This is a red brick with the brand M180-M200. In terms of frost resistance, it is on the same level with previous products. Since the material does not have an attractive appearance, it is only suitable for laying hidden furnace elements.

Chamotte brick (refractory)

Similar products are produced by many Russian factories. The quality is different for everyone: there are both good samples and extremely unsuccessful ones. At the same time, the price does not differ significantly. High-quality fireclay bricks should have a high density, uniform cream color, sharp edges. The standard product size is W8, but manufacturers offer various parameters and shapes.

The main purpose of fireclay bricks is the laying of furnace furnaces or internal elements of fireplaces. But you can not be limited only to the hot parts of the devices, because such material is often used to build the entire furnace.

Currently, oven "bread chambers" have gained some popularity - special departments in which bread can be baked. Unskilled specialists use fireclay products for their arrangement. Doing so is strongly discouraged. Refractory brick is a product of the chemical industry, and its contact with food is highly undesirable.

Brick LODE

This is a red solid brick, the strength grade of which is M500. Products are manufactured in Latvia. The material has high frost resistance, therefore it is excellent for outdoor work. Has three working surfaces, slightly rounded edges and edges. The manufacturer offers various shapes of bricks, such as semicircular. The appearance of this product is very attractive, because it is widely used for facing works.

Collapse

If you decide to build a reliable brick oven for a country house, knowing the rules for choosing the main material for work - refractory bricks and average prices in your area will help you. Material from domestic and Belarusian manufacturers is most in demand, but it is important not to chase the advertising crane and not buy a defect.

Short description

Refractory bricks for the stove are able not to collapse and deform under the influence of high temperatures - the main difference from conventional building materials. It is made from several grades of clay with additives of substances that increase the heat resistance of products.

It is recommended to use several types of building materials when laying individual parts of the furnace. For lining the outer layer, red ceramic or white silicate is used, and the firebox is lined with fireclay bricks. It is important to maintain the overall color scheme of the heater from the outside and from the inside.

In order not to overpay, for a household oven you should not buy parts with a brand over M-300. The numerical value indicates the margin of safety of products. If the grade is below 100, such a material is of poor quality with improper geometry and density of the material. M-500 bricks are used when laying industrial or powerful units.

Classification and characteristics

This type of building materials is subdivided into ordinary furnace (chamotte) and facing.

fireclay

You see a photo of fireclay bricks for the furnace above. These full-bodied products must be made according to certain sizes, without chips and voids. Such products withstand heating temperatures up to 1500 0 and are not subjected to deformation and destruction from such temperatures.

It contains up to 70% refractory clay with the addition of fireclay chips. After molding, the parts are subjected to strong heating, aluminum oxide is formed on the surface, which gives the material additional strength.

According to the requirements of GOST, several types of fireclay bricks are produced:

• ША - ordinary blocks that can withstand heating temperatures from 1750 0;
• ShB - the most popular type for home construction, capable of withstanding heating temperatures up to 1600 0;
• the marking "PB" and "PV" belongs to semi-acidic blocks, in which the content of silicon oxide is increased. This building material can be manufactured with 30% voids - this significantly increases the time it takes to heat up and cool down. The best option for the construction of a chimney, barbecue or tandoor;
• "SHL" - lightweight brick with a high level of fire resistance.

In terms of size, much depends on the series and type of blocks. Rectangular have dimensions (W, D, H) - 114/230/64 mm or 172/230/76 mm. if the main dimensions are 114/345 mm, such blocks are made only 76 mm thick. blocks, type "Leshchadka" are made in 2 main sizes - 114/230/64 and 114/230/38 mm. The square blocks are available in 230/230 mm sizes, 64 mm and 76 mm thick.

Facing

Powder of coke, quartz, pressed graphite is additionally added to the composition of these blocks. These additives increase the level of resistance to high temperatures up to 1000 0 compared to conventional building blocks. Such material is used to line the outside of the oven and is not considered a fire-resistant material. But such material is able to withstand low temperatures, accumulate and gradually release heat into the room.

Several types of such blocks are produced with polished surfaces and chamfered for laying decorative bas-reliefs. The dimensions of refractory bricks for furnaces have one standard - 120/250/65 mm, but several types of such blocks are produced that are different in shape and appearance. For the construction of an arch or the formation of a corner, curly or radial products are produced.

By color, you can choose the right shade - from straw to traditional red. In terms of strength - the maximum allowable marking of blocks for laying the M-150 furnace.

All other characteristics should be selected according to your climate zone and stove power.

Which refractory brick is suitable for the furnace?

Heat-resistant brick for the furnace must be selected based on the power and size of the unit. For a home or sauna heater, it is better to use fireclay blocks marked ShB for the interior decoration of the furnace compartment and the cooking cavity, blocks with the “PB” index are suitable for the chimney.

Overlay the outer layer, depending on the overall color scheme of your room, you can use stove bricks marked M-150.

Building a firebox with fireclay bricks

Every detail can be made from the best material. For the manufacture of an external wall that will be plastered or a foundation, refractory bricks with deviations in geometry can be used. Such a low-grade brick is much cheaper, but will require more attention when laying.

For a sauna heater, you will need to buy non-chamotte and non-quartz material - this is work for ceramic waterproof brands of blocks. Clinker tiles are best suited for this - but such material is expensive.

Important! When choosing a material for construction, one should not chase after its cheapness. Be sure to check all documentation and quality of materials.

How to choose a quality brick?

When buying, be sure to selectively examine the entire batch of blocks, perform a visual inspection of the material. Experienced builders recommend paying special attention to several points in the table.

Color	It should be evenly painted over all surfaces and in places of chips or in a section. If you saw enlightened areas - such material could not withstand a certain place under the influence of high temperature during firing. Dark spots at the fracture points indicate a violation of the temperature regime, such a brick was subjected to high temperatures.
Inclusions.	If small inclusions of a different color are found at the fault points, there is an admixture in such blocks, which is not always useful. If mica-covered areas are found on the surfaces, it is not recommended to buy such material, this is a 100% marriage.
Block shape.	It must be geometrically correct, with right angles. There are significant chips or other defects on the edges - this is regrading or marriage.
Dimensions.	If during the measurement a deviation of 2 mm from the dimensions of the block is detected, such products are made in violation of the technology.
Sound.	If the brick “sings” with a clear sound upon impact and there is no significant dent on the surface, you can safely pay for such a product.

Manufacturers and prices

Block manufacturer and name	Material strength value	Frost-resistant responsiveness	Dimensions (W/D/H) in mm, weight	Average price per piece
"SHA-22" from the Borovitsky plant of refractory materials.			114/230/65 or 55,	From 63 rubles
Red oven brick from the Vitebsk brick factory.
Rectangular red refractory brick for stoves from Lode
"SHA-5" red fireclay brick. Novomoskovsk.	200	F25	114/230/65,	30 r.
Single kiln solid brick. Producer "Gzhel".

The cost of fireclay bricks for a furnace exceeds the price of furnace blocks by almost 2 times. The most popular among stove-makers are the blocks of the Borovitsky and Novomoskovsky brick factories. Among the ceramic finishes, bricks from the Lode company are distinguished. Vitebsk blocks M-200 is the standard for this series.

Where can I buy?

This question is important for many home craftsmen. Definitely - large specialized construction stores. It is better if the company is an official dealer of the manufacturer's plant.

Not the most important thing is where to buy stove blocks. It is much more important to check their quality and all the documentation from the sellers. Sometimes building markets wind up a high price for products of well-known brands. Use the data given in this article and carefully check the quality and measure the dimensions of heat-resistant bricks. At the slightest deviation, think - maybe go to another store and look for quality material?

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Valuable for its beneficial effect on health: in a house with stove heating in the cold season, optimal humidity and a generally favorable microclimate are maintained. Provided: brick for furnaces is selected, rejected and used correctly. Otherwise, the effect may be opposite.

The correct assortment of bricks for the furnace significantly affects its efficiency. A good share of the heat of the furnace, built of completely good-quality bricks randomly, without linking their properties with the place of the brick in the structure of the furnace, will fly out into the chimney; especially when kindling. That's why when building a furnace, use bricks of the same type from the same batch and even from one pallet you need to parse. A good stove maker always starts with a thorough revision of the prepared brick.

Note: efficiency for brick ovens is especially important, because. their efficiency with the same design is highly dependent on the materials and method of construction. The parameters declared by the developers were removed during prototype testing. In order to achieve the same from your stove according to the finished project, brick and masonry mortar must be selected strictly according to the specifications of the authors.

Nowadays, more than a source of comfort and a symbol of prestige. However, it does not need to be put, if only it would fit under the finish. Firstly, if you choose quite a bit of a special type of brick for the furnace part (see below), you can turn a simple English fireplace into a full-fledged heating device and thereby save a lot on heating. Who is stopping you from using, say, the branches left from pruning the garden for firewood? And the brownie CO sensors, sensing warming, will reduce the gas supply to the boiler.

Finally, by using figured bricks for a fireplace, it is quite possible to give it a solid and / or elegant appearance without expensive finishing, see fig. Overpayment for shaped bricks at current prices will be much less than the cost of finishing work. And a real fireplace will give respect to the owner much more than a ready-made bio-furnace with glass. The latter, whatever you say, is more economical, but it is painfully man-made. And the positive psychological effect from it is weaker, experts are unanimous in this too.

Based on all this, and let's go through the bricks from the stove. That is, let's define:

• What type and grade of brick is suitable for which part of the furnace structure.
• Where to get the right brick for stoves and fireplaces.
• How to sort and discard.
• What kind of brick is suitable for finishing the stove / fireplace.

Worker or furnace?

The easiest way, of course, is to buy a special oven brick. But, firstly, not everything is so simple. Furnace brick is, in general, the same ceramic from selected raw materials, except for heat-resistant for the furnace part, see below. Many manufacturers, being in demand, draw out the brand of brick with additives, but they “forget” that the furnace must breathe, fortunately, there are no standard methods for determining the frequency and depth of its breathing.

Secondly, which directly follows from the first - the price. Special oven bricks are most often sold by the piece, depending on the brand and manufacturer - 16-60 rubles / piece. Sometimes - pallets of 320-360 pieces, from 12,000 rubles. for a pallet Or by weight, somewhere from 14,000 rubles / t; There are also about 300 bricks in a ton. Used from a disassembled stove can be found at 8-12 rubles / piece. A for a more or less decent oven, you need from 1500 ordinary and 200-400 refractory bricks, which are 1.3-3 times more expensive.

Therefore, we will proceed from the fact that the most common ceramic brick will go to the furnace: a worker for the main building and a front one for facing. The methods of its rejection are the same as for the furnace; In most cases, the quality can be preliminarily determined without visiting the warehouse, from the photographs of the samples. Of course, you need to spread your hard-earned money only after examining the game.

As for the mismatch of the module (base size) of ceramic and refractory bricks, this is in the past. Today's refractories are manufactured in different modules, and it is easier to determine their quality by external inspection than a working brick.

What kind of bricks are in the kiln?

The structure of the furnace is laid out mainly from red ceramic bricks for working (ordinary) and front, with even smooth pokes and spoons. A poke, a spoon and a bed are the traditional names for the sides of a brick, see fig. According to them, laying methods are also named, depending on which side goes out. Spoon - spoon laying or laying with spoons; poke - acc. poke or poke masonry. Bed laying is not provided for by building codes. fragile, but in some cases it is used at your own peril and risk for decorative purposes, for example. for facing round furnaces.

Furnaces are laid from solid bricks, without internal voids and single, i.e. single height resp. module (basic dimensions) of this type of brick. For different types of bricks (see below), the modules may be different. It is highly undesirable to use bricks of different modules for the same furnace, because then it is impossible to make the correct dressing of the seams and the structure of the furnace will be fragile. In extreme cases, a firebox is placed from a brick of another module, because. due to thermal deformations, it already has to be made in the form of a block built into the body of the furnace, untied with it by thermal compensation seams.

What kind of brick is not allowed in the oven?

Completely unsuitable for building a kiln is unbaked raw brick, silicate and cast by slip casting. The first is hygroscopic and will become sour from the breath of the furnace even in a dry room. The second is not heat resistant and conducts heat too well. In the third, the binder does not sinter, but shrinks, and when the furnace is fired from regular thermal shocks, the slip brick crumbles. Hollow bricks are suitable only in one case described below. Due to the same thermal shocks, unacceptable stresses are concentrated in them around the internal voids.

Red clay

For red ceramic bricks, the construction of the furnace means the method of its manufacture most of all. There are 2 of them: plastic molding and semi-dry pressing. According to the first method, the molding mass is passed through a profiled die before firing, obtaining a layer of the desired configuration in the section, and cut it into slices in size according to the module.

According to the second, the molding mass with a minimum amount of water is laid out in a mold, pressed, squeezing out water, and fired, as in the first case, for 8-15 hours at a temperature of 900-1150 degrees, depending on the properties of the feedstock. Semi-dry molding allows you to more accurately maintain the dimensions of the brick and get all its surfaces smooth.

For the furnace, ceramic bricks of exclusively plastic molding are needed. The fact is that water does not just give plasticity to the molding mass. When fired, it participates in chemical reactions in it. Simply put, the clay in pressed bricks sinters dry, which causes too many pores. Such a brick, firstly, does not hold alternating thermal loads well. Secondly, he breathes, figuratively speaking, like a driven horse.

About bricks with pimples

The Obolsk plant in Belarus has recently been actively offering kiln bricks with "pimples", see fig. The idea seems to be not bad: to increase the adhesion of bricks to the mortar and thereby the strength of the entire furnace. After all, furnaces are placed on clay mortars (see below), which are weaker than cement ones.

Everything would be fine, but you can’t make such a brick with plastic molding, obviously they are pressed. Accordingly, there are many complaints from users: when the stove is kindled after a long break (and which stove is heated all year round?), the bricks burst in the middle across. Exactly according to the main law of strength of materials: where it is thin, it breaks there. In general, they wanted, it seems, really the best, but it turned out as always.

About solutions

The main mortar for laying bricks in the oven is clay; about him . Cement-based mortars are used in two completely different cases - for lining the furnace and, in some cases, for the furnace part as the basis of heat-resistant concrete. It is used both then and then aluminous cement GTs-40 or GTs-50; it is unsuitable for outdoor work, tk. hygroscopic. The filler for laying the firebox is given either fireclay sand, or special fireclay aggregates ZShA and ZShB. The difference between them in the heating and cooking oven is imperceptible.

Refractory bricks

Refractory bricks are produced by pressing and firing at high temperatures. In the furnace business, bricks made of fireclay mass and, less often, quartz are used more often. The latter has a relatively small coefficient of thermal expansion (TKR), since it is made on the basis of quartz sand, therefore, masonry from it is carried out at the junction points in load-bearing metal embedded parts - beams, pallets, etc. But, since it is generally contraindicated to use loaded metal in the body of the furnace, and quartz brick is expensive and is afraid of contact with substances that have an acidic or alkaline reaction (lime, for example), it is also undesirable to use it in the furnace; except for one case, which will be discussed below.

Chamotte brick is the optimal furnace refractory. The method of its pairing with ceramic bricks has long been known: a seam widened up to 5-6 mm. With a properly prepared solution and conscientious work, it is absolutely reliable. Chamotte bricks come in different colors, depending on the grade of refractory clay - its base, see fig. higher. The best fireclay bricks are straw yellow. The methods for culling them will be discussed later.

Note: quartz brick can be very similar to fireclay, see fig. on right. However, to a fairly experienced eye, the difference is immediately visible - in quartz bricks, small dark inclusions are completely or almost absent.

About the size and shape of bricks

The dimensions of the working solid red brick are 250x120x65 mm (building module). If you build a stove from it, then you need to take the appropriate fireclay for the firebox. Fireclay bricks Sh-8 are produced in the building module.

However, the furnace is usually designed from the furnace, especially since a wide range of shaped fireclay products is now being produced specifically for furnace furnaces, see fig. Their dimensions are tied to the old-fashioned oven module 230x125x65 mm; this is the default oven brick size for most projects.

Brick Sh-8 is also available in a furnace module, so if you take it, do not forget to check the dimensions. In addition, fireclay bricks are produced narrowed, 230x114x65 mm and narrowed with a reduced thickness - 230x114x40 mm. Narrowed bricks allow you to design a firebox into a furnace made of working bricks: you have to break your head, but in the end the firebox still falls into place.

Shaped and facial

Of the shaped bricks, wedge-shaped or wedge-shaped bricks deserve special attention. They are ribbed, see Fig., And end. The former have the shape of an isosceles trapezoid in section; the second - in the plan. The dimensions of the bases of the trapezoid in the designation of the type of brick are given through a fraction, for example. 230x114x65/55 mm. The most common sizes of ribbed wedge bricks are 230x125x65/55, 230x125x65/45 and 230x114x65/55 mm.

End wedges usually go to the locks and heels of semicircular arches, pos. 1 in fig. below. For fireplaces they are produced shaped decorative, on the left in fig. at first. Since the arches of furnace furnaces are most often shallow sector ones, they are usually made from ordinary bricks with a variable joint width, pos. 2 in fig. The thrust bearings under the wings of the arch are then simply cut off on the horizontal masonry.

Another thing is box arches, three-center or semi-elliptical. They look great, but their heels must be made of ribbed wedge-shaped bricks, pos. 3, otherwise the arch simply will not withstand the load. In this case, you need rib wedges 230x125x65/45 with undercut, they are solid, and 230x125x65/55.

Facing bricks for furnaces, firstly, not necessarily, and not even always desirable, should be first-class. Most often, the cladding is the 2nd grade. Do not be surprised, the sorting of kiln bricks is carried out not by external gloss, but by other signs, indicating their thermomechanical properties.

Secondly, the front oven brick, like the worker, must certainly be plastic molded. Its sign is striking: these are cut marks on spoons, on the left in fig. Bricks, smooth and appetizing, like chocolates, on the right in the figure, are either pressed or slip, and besides, they are probably stuffed with non-heat-resistant polymer additives. They themselves will not withstand regular "thermal kicks", and they will not properly grasp the solution.

Clinker brick is prepared from a special mass based on clay - clinker - and fired at a temperature elevated to 1300-1500 degrees. In fact, clinker brick is a specially burnt ordinary one. It is dark in color, heavy, frozen colors of tarnish are often visible on its spoons, see fig.

The heat resistance of clinker bricks is up to 1200 degrees, it is very durable, its thermal conductivity is high. Due to the almost complete absence of pores, clinker bricks are very frost-resistant. It is not afraid of contact with most chemically aggressive substances, according to TKR it is in good agreement with red ceramic. It is rarely used in the construction of furnaces, because. expensive, and in terms of heat resistance it is inferior to fireclay, it holds up to 1500 degrees and above.

What should be the brand of brick?

With brands of bricks, there is a situation similar to the trade in computers. "Slows down" - you need a new "stone" (processor); under it, of course, the "mother" (system board) is also new. And the “wheelbarrow” to “fly”, most likely, just does not have enough “brains” (RAM), which would be many times cheaper. Well, the sellers will then offer to buy it when it turns out that it slows down anyway.

The numbers in the brand of brick indicate the compressive force, in kg / sq. cm, which he can carry indefinitely for a long time. Firstly, the brand of brick for laying an ordinary stove, as they say, is higher than the roof with a head, M150 is sufficient. For a two-story - M200-M250.

Secondly, the highest brand of brick that can be obtained from natural raw materials is M300. Then where do the M350-M500 come from? Most often - from synthetic additives. In housing construction, they fully justify themselves, but not in the oven. And the difference in prices - see the prices of merchants.

Note: however, the M75 and M100 brands are not suitable even for a summer stove. The raw materials for them are so bad that a brick from it is unsuitable for a furnace in terms of heat engineering.

Designations of brands of fireclay bricks are not closely related to their parameters. Most often, the cheapest Sh5, Sh8, ShA5 and ShA8 are taken for furnace fireboxes; the last 2 are lightweight (lightweight). In the furnace, the difference in the properties of these brands does not affect. Sh22-Sh45 is allowed on the furnace vaults; the first digit indicates the type of wedge (edge, end).

Brick in the kiln

The culling of bricks unsuitable for work and the selection of suitable ones will be dealt with in the next. section. So far, we believe that we know the result: 1, 2 and 3 grades. I must say that the division into varieties is conditional, it would be better to call them categories. Every vegetable has its time, and every brick has its place. A good brick for a stove is one that lies in its place in it and does its job. And there will be work for all "dischargers".

Now let's look at the oven in terms of bricks. We will see, see fig. on right:

1. foundation;
2. firebox;
3. smoke circulation;
4. facing;
5. chimney.

The foundation bears the weight of the stove and must be strong. But this is not enough, the foundation should not allow the furnace to dampen from below, therefore it should be, if possible, moisture and vapor-tight. Part of the foundation under the floor can cool below 0, so the foundation must also be frost-resistant. Therefore, a first-class brick is needed for the foundation (it will go to any part of the furnace), either the 3rd grade, or clinker. Which one? In this order:

• The cheapest, of course, is the second option (grade 3).
• If the stove is high and heavy (two-story Dutch, for example), then it is better to take the 1st grade, because. all varieties are obtained by sorting the same pallets, see in conclusion.
• In places with prolonged severe frosts, clinker bricks are preferable, they can withstand any weight.

The temperature in the furnace can reach 1100 degrees, which is the limit for ceramic bricks, at 1150 it begins to melt. The mechanical loads on the furnace are low, they are taken over by the body of the furnace. But the furnace must quickly take a lot of heat from the flame and transfer it to the accumulative (accumulating) part of the furnace - the smoke circulation and lining. Therefore, the firebox is made of fireclay bricks, its thermal conductivity is quite large compared to the heat capacity.

Note: in a heating furnace with a not very intense thermal regime (Russian,) it is permissible to lay a firebox from heat-resistant ceramic bricks. For more information, see brick for a Russian stove.

brick tooth

In this case, we mean not a brick denture, but the most important part of a classic English fireplace - a smoke tooth, highlighted in color in Fig. The tooth, firstly, must be strong, because. the ways of its masonry, providing full connectivity with the body of the fireplace, are unknown. But the main thing is that the tooth should reflect thermal (IR) rays well; the fireplace heats mainly by radiation, and the inclined surface of the tooth is a thermal mirror.

Based on this, the chimney tooth is the only place for which quartz brick can be unequivocally recommended. Once the builders of fireplaces avoided it, quartz brick is badly pricked. But now, when the master has a grinder with a diamond wheel at his disposal, this is no longer a problem or even a question.

The smoke circulation part does not directly contact the flame, but the flue gases in it are heated to 800-400 degrees. It is in the smoke circulation that they burn out, therefore they are still chemically active. In addition, a large proportion of heat from the heating is also accumulated in the smoke circulation part, and it must be given in moderation so that it is enough for the next furnace. So here the only option is a brick of the 1st grade.

Note: the thermal conductivity and heat capacity of a brick directly depend on its density. The first grade is therefore the first, because their ratio is optimal in it.

The role of lining in the heat transfer of the furnace is also significant, but most of all it participates in its respiration. Further, the finish should hold well on the cladding, which is not so easy to achieve: under the decorative layer once or twice a day it can be + 120-140, and outside - room + 18-25. Based on these requirements, it is best to overlay the stove with a brick of the 2nd grade: its heat capacity in this place is still sufficient, the porosity will ensure deep even breathing of the stove, and in combination with a rough surface - excellent adhesion to any mortar.

The chimney is considered to be the part of the chimney above the view. The temperature here can vary from +400 to -40 and below, humidity - from 10-20 to 100%. Precipitation cannot be ruled out. Mechanical loads are predominantly wind, i.e. any kind and direction. At the same time, the pipe in any climate must warm up quickly, otherwise the furnace will slowly increase traction, which will lead to excessive fuel consumption and increased soot deposition. The conclusions are as follows:

1. Under normal operating conditions - brick of the 1st grade.
2. If there is an old oven brick soaked in soot - a mezhigorka or a small brick - excellent, this is ideal. But you can put a mezhigorka only inside, otherwise dark spots will seep through any finish over time.
3. In places with a harsh climate - masonry of 2 layers: inside clinker brick (3rd grade is not suitable for replacement, it is not frost-resistant enough), and outside - hollow 1st grade. This is the very only case when a hollow brick in the oven is in place.

And what about a bathhouse?

Features of the work are sufficiently covered in other sources. Figuratively speaking, her breathing should be short and sharp, but not too deep. Therefore, a brick for a bath stove is chosen as follows:

• Fireclay and quartz are unsuitable: according to technical specifications, their use and storage at a relative air humidity above 60% are unacceptable.
• The firebox must be made of ceramic refractory bricks, see below.
• The rest of the stove in a family or public bath, where they wash in several shifts, must be laid entirely of first-class brick.
• It is better to build a small stove in a small bathhouse from clinker bricks: according to heat engineering, it will turn out to be almost equivalent to cast iron, which is optimal in this case.

Brick for Russian stove

The choice of brick for has its own characteristics:

• All orders of Russian stoves are designed for the original stove module 230x125x65.
• The entire furnace is laid entirely of ceramic bricks of the 1st grade.
• Under the furnace, it is laid out of refractory ceramic bricks: hearth or its analogues.

The name "hearth brick" has a double meaning. Firstly, as already mentioned, the hearths of Russian and Dutch ovens are laid out from it. Secondly, pallets with blanks of hearth bricks are placed on the bottom of the kiln or on the lower shelf of the rack with others. Thanks to this, the hearth brick heats up and cools down more evenly during firing, and its quality is excellent.

The hearth brick is sold separately. Of its analogues, the Gzhel refractory brick has proven itself well. Once upon a time, Borovichsky was also famous, but now it is full of complaints: it has lost its frost resistance.

Rejection and selection

Bricks obviously unsuitable for the furnace are discarded on the trail. features, see fig.:

1. With sizes that do not match the module.
2. Apparently fissured, with severe scuffs and burrs from cutting, with foreign inclusions - left pos.
3. Strongly burnt, very dark, swollen, warped, with spots appearing on the edges - middle pos.
4. Having traces of outgassing during firing in the form of rounded shells (caverns) with a smooth inner surface, right pos.

Note: for fireclay bricks, up to 4 shells per brick are allowed, but not more than 1 per face, see fig.

Types of bricks

Sorting of ceramic bricks is carried out as follows, see next. rice:

The first grade (on the left in the figure) is a moderately annealed brick with sufficient density, quantity and size of pores. The surfaces are smooth, the color is bright saturated from pure red to slightly yellowish. The sound when tapping 50 g with a hammer is metallic sonorous. Cut marks - no scratches; the edges are not crumbling. On the edges, often (this is the surest sign), iridescent spots or a continuous film are noticeable.

The second grade (in the center) is slightly underburned. Frost resistance is weak, porosity is increased, heat capacity is less than that of the 1st grade. Signs: more per ton (up to 420 pieces versus 320-340 for the 1st), unsaturated color (pale brick). The sound when tapping is clear and short, but deaf. Shallow cut marks and some chipping of the ribs are acceptable. There is never an iridescent film; if it is, then from polymeric plasticizers; such a brick is rejected.

The third grade (on the right in the figure) is moderately burnt. Dense (240-290 pieces per ton), but little porous and conducts heat too well. Weakly frost-resistant, but suitable for the foundation. It is very strong in compression, but it does not hold other loads well. Signs: color dark deep to brown. It rings when tapped, but the cut is torn and the ribs are often crumbled.

Note: burnt brick is often sold under the general name "iron ore". But, as we see, in the furnace iron ore is different.

About rejection of fireclay

The surest way to reject fireclay bricks is to drop them from a height of about 1 m onto a stone floor. At the same time, a good one breaks up into large fragments; bad - crumbles into a bunch of small ones. In production, chamotte is sometimes checked in this way, selectively, several pieces from a batch. That merchant will not allow anyone who is interested to beat his goods. In this case, the following algorithm should be followed:

• If you crawl your fingers across the ribs, the brick does not crumble and does not dust from this - it is suitable for further verification.
• The sound when tapping is ringing is quite long - 1st grade, suitable for any fireboxes, incl. furnaces with intense thermal conditions: bell-type, Kuznetsov furnaces.
• The sound is clear, short, jerky - 2nd grade, suitable for other fireboxes.
• The sound is deaf - marriage.

What is the best way to trim?

If the stove has an independent meaning as part of the interior design, then it is best to use plastic molded face brick for finishing it. He is almost always 2nd grade; this is just what you need for the shell of the stove. When building a new furnace, the facing bricks are simply laid outside. Then the finish turns out by itself, and 3 birds with one stone are killed at once: the oven breathes deeply, it takes on a look, if only the seams were neatly cut, and it comes out strong, because. All seams are tied properly.

If an old stove is veneered, then you can not think about dressing the seams of the masonry with the cladding, if only because the old ones have dried up. And the “thermal kicks” will once do their job and the lining will peel off. Previously, in such cases, the stove was first lined with unglazed tiles on lime mortar, and on top of it with bricks on the same mortar. The tile played the role of a kind of damper. Now you can do it easier and cheaper: knead the masonry mortar of the cladding on the same aluminous cements.

It also happens that the stove or fireplace, according to the designer's intention, should organically fit into the interior, at least as in fig. Then 3 options are possible: a narrow decorative brick, pos. 1 on the right in the figure, Yekaterinoslav hand-molded brick, pos. 2, and clinker facing tiles, item 3. The latter is expensive, but the best in quality: clinker tiles are well matched with bricks in terms of TKR, are durable, tenaciously sit on any mortar, are produced in various colors and textures and allow the furnace to breathe - in clinker a little porosity -there is, but the thickness of the tile is small.

A narrow brick is suitable for fireplaces: the stove lined with it will not be able to breathe. You need to purchase it with analysis: manufacturers often use polymer additives. The heat resistance of a narrow brick for facing fireplaces, according to the certificate for it, must be at least 140 degrees.

As for the heavily advertised Yekaterinoslav (or eagle) brick, there were no complaints about its quality. But the price is clearly too high compared to the capabilities of the material. Apparently, the marketing service is guided by the principle: "Mercedes" - for an asterisk, and we - for a double-headed eagle. Maybe they charge a fee for fear: Yekaterinoslav is the present Dnepropetrovsk, the specific fiefdom of the notorious pan (or rabbi?) Kolomoisky.

Although, who knows how n / r Kolomoisky is looking at this eagle. Already in something, but you can’t refuse him (p / r Kolomoisky, not an eagle) in resourcefulness. Here, it was decided once pp. national revolutionaries p / r Kolomoisky turn as a dangerous competitor. Like, it is impossible by law to be a governor with dual citizenship. So he immediately found: “But I don’t have a double, but a triple! Here, please, a Ukrainian passport, here is an Israeli one, and here is a Cypriot one! Where is it in the law n-π multiple citizenship is prohibited? So you, please, charge two-passport even into a cannon uncut - and on separatist terrorists. And don't touch me! I have a triple passport, I can! Not that - the battalion lads will immediately explain how the laws should be interpreted!

Scratched pp. revolutionaries are national where they wear a hat: and it's true, there is nothing in the law about n-π multiple citizenship. Not spelled out, not thought out, as well as about the only possible thing that would be more correct and simplest. They retreated, and so the colonel Kolomoisky remained to rule his patrimony.

In conclusion: what to choose from?

Dealers, of course, will not offer bricks of 2-3 grades. And manufacturers - to sort the output: for industrial and civil construction, all 3 grades of bricks are suitable. And they meet randomly on the same pallet.

Having planned to build a furnace, you must first calculate, according to its project, how many of which type of bricks will be required. Since more than one pallet will go to the oven, it is possible, after looking at the seller’s pictures and prices, to select suitable pallets in the warehouse directly by color; It is best to invite a good stove-maker with you for this. Then - a sample for tapping selectively. And in the process of laying a brick back and forth, frankly, it does not play a decisive role.

Laying a stove is a difficult task, but not so much that you do not master all the professional subtleties, especially if you want to make a home with your own hands. Today, stove makers charge dearly for their work, in order to save the family budget, you should try to fold the stove yourself.

How does a typical oven work?

The furnace is a single organism, consisting of different departments, each of which experiences its own physico-chemical, thermal, mechanical loads of a different plan. In addition, different units of the unit are in different humidity conditions, so their construction requires the use of different building materials, bricks and mortar.

The structure must have a foundation (1) located below the floor level (3), on which the waterproofing (2) is laid. The under-furnace (4) rises from below and is the support of the furnace body. Brick for this department of the unit must have special strength, be resistant to negative temperatures.

The crucible or firebox (5) must withstand extremely high temperatures, it needs fireclay bricks inside and refractory kiln outside.

The source of the chimney (6), as well as the rest of the interior of the unit, requires refractory stove bricks, durable, resistant to temperature extremes. The best brick for this is ceramic.

Of considerable importance is the aesthetics of the hearth, for this cladding is used. In order for the surface (7) to be attractive and also to radiate heat well, a solid type of building material is used.

The top of the chimney (11), where the damper is located, above its ceiling part (8), elements that are not exposed to the environment require durable material. For the outer pipe (9), located on the roof (10), a material of special strength is needed. Since this part is subjected to serious loads from humidity and temperature changes, bricks should be selected according to the following principle. From the inside, lay a heat-resistant ceramic brick, and from the outside - with minimal thermal conductivity characteristics, then condensation will not form, destroying the pipe.

What material is needed for the chimney?

The main function of the chimney is to remove combustion products and provide good draft to stimulate the combustion process. The brick is needed refractory, withstanding t100 °, high-quality with a minimum value of M200, made of clay and quartz sand. The material should be even with well-defined edges, high firing. Optimal dimensions bed25mm, lozhlk12mm, poke 6.5mm. Color red, brown.

Brick for kiln body

For laying the stove, fire-resistant or stove bricks are used. There are 4 varieties:

1. quartz, consisting of clay and quartz sand;
2. carbonaceous, consisting of a graphite-coke mixture;
3. the main one, consisting of a lime-magnesite mixture;
4. fireclay, consisting of fireclay clay and sand.

All types of material are produced under high pressure by firing.

The material used for the furnace body must have high thermal conductivity (solid) and withstand high temperatures of the order of 100 °, grades - M200, M250.

Brick for firebox

The crucible is laid out with fireclay bricks, the marking of which begins with the letter “Sh”, the next letter “A” means the ability to withstand t 1400 ° or the letter “B”, which indicates the ability to withstand t 1350 °. Further marking indicates the dimensions:

• 250x124x65mm;
• 230x114x65mm;
• 230x114x55mm.

Fireclay has a yellow color, is produced in accordance with GOST -390-96. If there are light shades, it means that the technology was violated during firing, you should not purchase such products. Red or brown inclusions are acceptable, indicating the presence of iron or other minerals.

Facing brick

Density is responsible for heating the unit and retaining heat in the room. The denser the material, the longer the stove will heat the room and the heat will last longer in it.

For the furnace as a permanent and main source of heat in the house, facing bricks of the M250 brand and above should be used. Optimal conditions are guaranteed.

The higher the brand of brick, the better its aesthetic performance. Quality products have a smooth surface, without flaws on the front side and rough, which improves adhesion to the mortar from the inside.

The modern market of finishing materials offers a wide range of colors and textures that allow you to create a beautiful appearance of the stove, making it a true interior decoration.

What you need to know about the main parameters of brick for the furnace

Strength characteristics, as already mentioned, are denoted by the letter "M". The indicator displays the ability to withstand mechanical stress. A simple stove can be lined with M150, for a massive high structure M 250 is required.

Important! Experts say that the M300 - M 500 grades contain special additives that, during the heating process, can poison the indoor air.

The letter "F" stands for frost resistance. The higher the digital indicator after it, the more resistant the material to frost, the better it is suitable for building a foundation and a pipe.

Be sure to pay attention to the indicators of thermal conductivity, which for laying the hearth must be at least 0.61 W / m × ° C.

Equally important are the indicators of hygroscopicity, which is expressed as a percentage of the mass. The lower the indicator, the better it is suitable for laying any section of the furnace.

Several tips in a row!

• You should not use a hyper-pressed brick, its main drawback is the lack of plasticity, cracks will certainly appear, it releases carbon dioxide when heated, and has a large mass.
• The best choice for laying a hearth is ceramic brick, all of its varieties are hollow, solid. The latter is preferable.
• Atmospheric dry clay bricks must not be used! It will turn to dust very soon.
• Clinker, which is characterized by high strength and excellent frost resistance, has a high mass, and is also expensive. It is used to lay the underside and the inside of the chimney; it is not suitable for the body of the furnace, despite its excellent performance. He's not breathing!

The beauty of a fireplace primarily depends on the quality of the bricks, and only secondarily, on the quality of the masonry. Although, of course, both are very important. The term "cladding", if the fireplace is made of facing bricks, is not entirely correct. After all, they are not veneered, but a fireplace is built from it. But, due to the fact that it is not refractory, but is laid on top of it, this term has taken root. Refractory is placed in the firebox of the furnace, and in the fireplace as a vault over the hearth.

The facing brick is laid on top of the refractory brick and must be bright, very smooth and, of course, must retain heat for a long time. The construction of a fireplace, although different from the construction of stoves, is not very dramatic. Ordinary stoves are built from special stove bricks, and the finish is usually made with tiles. This is at best, usually the improvement of the outer surface of the furnaces occurs by plastering and subsequent whitewashing. The processes (plastering and tiling stoves) are very different from brick cladding. Here you need a specialist of a narrow profile.

The fireplace, in a modern dwelling, unfortunately, does not fulfill its main role - heating, as stoves used to do. It is rather an aesthetic component of the interior, and is only occasionally used for its intended purpose. Yes, it is impossible to cook food in it, as in a Russian oven, but it is not intended for this. But from this the value of the quality of the cladding only increases. The brick that is used for these purposes, in principle, can be not only purely facing, but also any other (antique, figured, solid or hollow, hand-molded, semi-dry or plastic pressing).

It all depends on the desire of the owner. It is only necessary to remember that some brands do not withstand high temperatures and may crack. For this reason, a highly qualified specialist should produce the cladding. He knows exactly which brand of brick can be used and which can not. As a rule, special facing bricks are used for these purposes, which are used for lining furnaces, the so-called “furnace” ones. Here are some of his brands:

• Pobeda LSR (chimney brick)
• furnace brick Vitebsk
• Latvian fireplace Lode
• furnace full-bodied TERCA (Grater) manufactured by the Wienerberger concern
• Belgian TERCA hand molded.

Modern technologies make it possible to produce bricks of almost any color and any shape. How this is done, we will consider below.

Manufacture of facing bricks for a fireplace and its marking

The technology for the production of facing bricks for fireplaces and stoves has significant differences from the manufacture of conventional building bricks. Qualitatively executed surfaces of spoon and bonder faces are its distinguishing feature. They are not only smooth, but also textured or even specially aged. Many types have chamfers on the edges, thanks to which accurate jointing is possible. Facing never has cracks, calcareous inclusions, spalls.

Its color is even over the entire surface. The dimensions are more accurate than those of a conventional, building or used for the construction of furnaces. According to GOST, the deviation from the standard size should not exceed 4 mm in length and 3 mm in width. The difference in thickness is plus 3 and minus 2 mm. As for straightness, the deviation is not more than 2 mm. The color scheme, as mentioned earlier, can have a variety of shades: from natural light yellow to dark blue and even black.

The production of facing bricks (both for stoves and for fireplaces), like any other production, improves over time. So, in recent years, this production began to take on other forms. Instead of forming a tape from clay, and cutting into bricks, and then firing, dry production became popular, and even from construction waste. With the old method, a moistened mass of sand and clay is fired in a kiln. But the time of ovens is irrevocably passing. So, for the dry method, only a press is needed. All the necessary components are crushed in a crusher, mixed and pressed. This method is called supercompression. Moreover, in order to form bricks, there is no need to press each of them or even a batch. Everything happens in a continuous cycle by feeding the raw products into the hopper connected to the screw press. The press creates the necessary pressure and temperature that are needed to sinter the components. When the mass of their press comes out, the mass (if it can be called mass) is cut into pieces of the desired size. And then, already finished bricks cool in the air and acquire the declared depravity.

In the production of such a facing material, metal production waste, slag from the furnace and much more can be used, what was previously considered garbage and was thrown into a landfill. At the same time, this does not affect the quality of the facing brick in any way. The consumer is usually not at all interested in what material it is all made of. Especially if the brick is painted and the surface is embossed. Of course, such a product cannot have a natural color and synthetic dyes are used for dyeing. But the price of this is much lower than ceramic. The price of a brick for the construction of a furnace (furnace) is about three times lower than a refractory (fireclay). Facing, produced according to the old technology (with firing in a kiln), is about twice as expensive. And according to the new technology (without firing in the furnace) it is sold at the price of fireclay. In order for the market to have a choice. And the choice is up to the consumer.

Types of facing bricks

Classification:
By form:	like a brick like tiles.
By the presence of voids:	hollow with more than 13% voids full-bodied with voids less than 13% with parallel voids relative to the bed with perpendicular voids.
By size (dimensions in mm):	single 250*120*65 one and a half 250*120*88 american 250*60*65 thin 250*20*65.
By color:	natural colored.
By type of front surface:	smooth raised chipped.
Product shape:	rectangular shaped.

Marking

The facing brick is marked, for example: DIN 105 - VHLz B 28 - 2.0 - 2 DF. What does it mean: multi-hollow with void class B, with density class 2, compressive strength class 28, in 2 DF format, which means the size is 240*113*14mm.

But only foreign-made bricks are marked this way. Domestic is marked as follows. Facing brick marking 1 – NF F50 M25. Where 1-NF means size F50 means frost resistance on a scale of 35 to 100. M25- means mechanical strength. The higher the number, the stronger the brick.

Conclusion

What material for the construction of fireplaces can only be decided by the buyer. Suggesting or imposing your opinion is not in our competence. Just one piece of advice, if you will. Do not make a decision spontaneously, consult with experts. And preferably not with one, but with several. Then your choice will definitely be right. Good luck with your construction.

The variety of tiles for the fireplace: which one to choose and how to veneer?