Height of the fireplace from the floor. What should be the dimensions of the fireplace for normal operation? Hearth dimensions

Engineering, thermal calculation of fireplace pipes is quite complex. The initial conditions set such an air speed (0.25 m/sec) entering the portal (window) of the fireplace, the flow of which should ensure that the fireplace portal is blocked from those emanating from the hearth flue gases. Ultimately, the calculation comes down to determining the parameters of the pipe, its height and flow area, the aerodynamic parameters of which should ensure the performance of this particular fireplace.

Various factors are used in the calculations (the main factor is the difference in temperature of the external air and flue gases), such as: permissible (desirable) speed of gas passage in the pipe, smoothness (cleanliness) of the inner surface of the pipe, possible (permissible) deviations from the vertical of individual sections of the pipe ( kinks of the pipe axis) and other indicators that directly affect the draft resistance in the pipe. In addition, air pressure, the influence of air flows, etc. are also taken into account. A number of real indicators in the calculations can be taken into account empirically, through the introduction of correction factors; they are often subjective in nature, which can also affect the calculation results.

It should not be surprising that in various sources (tables, diagrams, nomograms, etc.) there are recommendations that may differ significantly from each other. Here are other factors that influence the accuracy of calculations and introduce an element of uncertainty into them:

• actual temperatures of outside air and flue gases usually differ from the average calculated ones,
• unaccounted for air leaks through possible leaks, for example, in a pipe, increases the amount of flue gases and lowers its temperature,
• The draft in the chimney is affected by the amount and humidity of actually burning fuel in the fireplace, which can differ significantly from the calculated one.

How are such things resolved? complex tasks on practice? There are several ways aimed at a simplified solution to the problem, we list them:

1. Formalization of engineering calculations in computer programs. The use of such programs greatly facilitates and speeds up the solution of practical problems. This is the most desirable approach, but the problem is that it may not be widely available. There are no standard programs, and their preparation can only be done by highly qualified specialists who are well versed in the theory and practice of thermal engineering, hydraulic and gas dynamic calculations, as discussed above. At the same time, good knowledge of computer practice by such specialists is no less important.
2. Most often for practical application It is customary to use tabular data that sets pre-calculated results for fireplaces. There are many such tables; for example, the Index contains about 20 of them, all of them borrowed from various foreign sources1. In them, the recommended sizes, as a rule, are linked to each other without indicating possible deviations. The tables also include sizes that are not classified as basic (the first category), which can mislead the performer. It is advisable for the contractor to know which dimensions in the table are “main” and which dimensions are “non-main” (if they are included in the table). He also needs to know: within what limits the recommended table dimensions can be changed without the risk of getting a negative result as a result of his work in the form of a smoking fireplace.
3. Use of various kinds of graphic materials in the form of nomograms and diagrams. In them, the calculation results are summarized in graphical indicators. This approach has its advantages: often well-designed diagrams present a clear graphical picture that can show general patterns in the calculations. It cannot be caught if you use other methods (including one-time thermotechnical and other calculations).

The advantage (and at the same time disadvantage) of this method is that auxiliary indicators can also be specified in the form of initial indicators. For example, enter a second category of sizes into the nomograms. However, often such nomograms become not only difficult for practical use, but also lose the main thing: the advantage of clarity. For this reason, not everything that has been created in this part for calculating fireplaces can be recommended for practical use.

In passing, we note that the graphical, simplified method is used by the most reputable companies producing fireplaces and chimneys. Such firms create their own nomograms, which allows them to unify the approach to calculations across all of their many divisions. This, in turn, allows them to avoid possible discrepancies in calculations when selecting pipes for their consumers. One of these nomograms is shown below (Fig. 3.2).

Rice. 3.2.
The nomogram (diagram with nomogram), developed by SCHIDEL, reflects the selection of round fireplace pipes for open fireplaces. The right part is intended to determine the cross-section of the channels for supplying air to the fireplace from the outside, necessary for its normal operation

The diagram compiled by Swedish researchers has been used in domestic practice and has been thoroughly tested; it is reproduced in Fig. 3.1. Let's explain it.

Rice. 3.1.
Diagram where: H - pipe height in m; f - cross-sectional area of ​​the pipe (flow area in cm 2 ); F - area of ​​the fireplace portal (dimensions AX B) in cm 2 ; (f/F) x 100 - percentage of area f of area F. The configuration of pipe sections is shown at the top

The presence of three curves in the diagram is explained by the following: the geometry of the flow section of the pipes is the determining indicator for chimneys, because with equal cross-sectional areas of pipes of different geometries (round, square and rectangular, as marked in the diagram), equal pipe draft is created at different heights. For example, with f/F = 10%, a pipe with a round cross-section will create sufficient draft at a pipe height of H = 7 m, a pipe with a square cross-section at a height of 9.2, and a pipe with a rectangular cross-section at a height of 10.8 m. Let us pay attention to quite the unexpected result that the diagram shows: the difference in the heights of the pipes is too significant (up to 3.8 meters, which practically corresponds to one and a half floors of the building!).

We emphasize that such a difference in pipe height is the cost of a possible error due to unskilled pipe selection.

The behavior of gases in a pipe is shown in Fig. 3.3. It can be seen that the flue gases swirl and pass through the pipe in a vortex, screw flow. The main flow of gases is located around the axis of the pipe. The figure shows a cross section of this vortex. Independent vortex flows are created in the corners of the pipe, which do not contribute to the main flow, but interfere with it. In round pipes there are no additional turbulence flows, and in rectangular pipes they are greater than in square ones.

Let's return to the diagram (Fig. 3.1), to the vertical drawn at f/F = 10% and the height points on it at 7m, 9.2m and 10.8m. It is said above that pipes with the same cross-sectional area, but different geometries (circle, square, rectangle) create equal thrust at the indicated heights.

Let's consider the option of installing the same fireplace (a fireplace with equal parameters) in houses of different heights and a scheme for selecting a pipe for this fireplace. For example.

1. 3-storey house (height 10.8 m),
2. Cottage (height 9.2 m),
3. House with an attic (height 7 m).

The choice of pipe for this fireplace can be completely different. A fireplace that requires a 10.8-meter rectangular pipe (option 1), in the second option (9.2-meter pipe) will need to at least install a square pipe, because The old pipe with a lower height will not ensure normal operation of the fireplace. In the third option, the operation of this fireplace can be ensured by a round pipe, because pipes of rectangular and square sections will not be able to ensure the operation of this fireplace. Let us repeat for clarity that in the example considered, with different geometries, the cross-sectional areas of the pipes are the same.

On the same diagram we will draw horizontal lines at heights of 5m, 7m and 10m. These heights are generalized, they are characteristic: the first is for the modest country house, the second for a house with an attic and the third for a cottage.

These heights will correspond to the following indicators:

1. For H = 5 m - 11.2% (round pipe), 12.4% (pipe square section) and 13.2% (rectangular pipe).
2. For H = 7 m - 10% (round pipe), 11% (square pipe), 11.7% (rectangular pipe).
3. For H = 10 m - 8.7% (round pipe), 9.7% (square pipe), 10.2% (rectangular pipe).

It is these indicators that form the basis for the selection of fireplace pipes; they are obtained using engineering calculations, then summarized in the given diagram and derived from it.

The accuracy of the given indicators may vary within tenths (0.2% for horizontal axis and 0.2 m for the vertical axis), which is quite acceptable for practical use and does not have a significant impact on the final results.

These indicators can be remembered: for a rectangular pipe 13.2-10.2%; for a square pipe 12.4-9.7%; for a round pipe 10.0-8.7%.

Moreover, the general pattern is important: larger values ​​are intended for pipes with a smaller height.

Experienced craftsmen rely on them (usually they remember the extreme values ​​of 13.2 and 8.7), you can always return to them by referring to the diagram. It is on them (including other heights) that the tabular recommendations, which are usually found in various sources, are based.

From the above, we can draw some conclusions for practical work: in the list of preferences when choosing, the round cross-section of the pipe is in the first place, in the second - square, in the last - rectangular. This reflects the position of the curves on the diagram. Here is the answer to the question: why are branded fireplace inserts equipped with a round pipe that determines the cross-section of the stainless pipe that fits onto it. Note that round pipes are more economical in terms of material consumption than square or rectangular pipes. Especially it concerns stainless pipes, since the cost stainless steels significantly exceeds the cost of ferrous metals.

When using pipes with square and rectangular sections, it is advisable to make rounded corners (note: despite the fact that the cross-sectional area of ​​the pipe f decreases), which helps to reduce harmful vortex flows to a minimum or get rid of them altogether. This is easily achievable when forming block pipes or using a pipe-in-pipe option, such as a round insert into a brick pipe.

And two more conclusions.

I. Due to the fact that the results of calculations of pipes with different cross-sectional geometries (round, square and rectangular) show a significant difference, three different (corresponding to cross-sections) Tables 1 can be recommended for practical use.

II. It is not advisable to include structural dimensions (the second group of dimensions) in these tables.

Therefore, we will once again return to the group of structural dimensions, we will show which recommendations for them are generally accepted (Fig. 2.1), this will be discussed in more detail in the chapter Structural solutions.

1. Firebox depth, size C.
2. Dimensions that determine the angular position of the side walls of the firebox.
3. Dimension G. Tooth position to the edge of the portal slab.
4. Size Nd. Smoke collector height
5. Dimension M. Determines the narrowing strip for the passage of flue gases into the smoke collector chamber.
6. Dimension L. Defines the beginning of the rear wall slope and leaves room for fuel placement.

To carry out calculations, we use the most typical pipe heights from the practice of building dachas and cottages: 5 m; 6 m; 7 m; 8 m; 9 m; 10 m and 11 m. Let's summarize the results shown in the diagram into a table. Please note that the f/F ratio in % ranges from 8.5 to 13.2%, with smaller values ​​for round pipes, and larger values ​​for rectangular pipes.

Table 1. Basic parameters of fireplaces and pipe cross-section geometry

Pipe height H, m	f/f ratio in %
	5	6	7	8	9	10	11
Pipe section	Round	11,2	10,5	10,0	9,5	9,1	8,7	8,5
	Square	12,4	11,6	11,0	10,5	10,1	9,7	9,4
	Rectangular	13,2	12,3	11,7	11,2	10,6	10,2	9,8

Calculation example 1.

Fireplace with portal dimensions: A = 77cm, B = 63cm; the height of the pipe from the floor to the top is 7 m, the pipe is brick. We need to pick up a brick pipe. Let us show how this problem is solved.

Portal area F = A x B = 77 x 63 = 4851 cm 2; calculated, effective height Nef = 7 - (0.63+0.3) = 6.1 m, where 0.63 is the height of the portal in meters and 0.3 m is the height of the base of the fireplace (expected). Neph = 6.1 m is closer to the table 6 m. The f/F ratio in accordance with the table: for a square pipe section - 11.6 and for a rectangular section - 12.3. The pipe cross-section f is determined from the equality (f 1 / F) x 100 = 11.6% and (f 2 / F) x 100 = 12.3%; f 1 = (11.6 X 4851): 100 = 562.7 cm 2; f 2 = (12.3 x 4851): 100 = 596.7 cm 2

We select pipe sections close to the calculated ones (see Table 2): square section (pipe No. 2) 6 bricks/row - 676 ​​cm 2; rectangular section (pipe No. 4) 7 bricks/row - 669 cm 2.

The performer remains to make the final choice from 2 options, because both options, judging from the calculation point of view, are practically equivalent. However, preference should be given to the first option: compare the costs (in terms of labor and brick consumption: in the first case 6 bricks/row, in the second 7 bricks/row).

Calculation example 2.

Pipe channel in the wall or separately standing pipe No. 1, the channel cross-section is formed by laying 5 bricks / row with a design cross-section f = 338 cm 2 (see table 2) . The pipe cross-section is rectangular. The height of the chimney is 8 m. The fireplace is attached to the chimney (to the wall) according to the Finnish type (rice. 2.3). It is necessary to determine the dimensions of the portal (window) of the future fireplace.

№	Bricks	Flow section in bricks
1	5	0.5 x 1.0	13 x 26 = 338
2	5	1.0 x 1.0	26 x 26 = 676
3	6	0.5 x 1.5	13 x 38 = 494
4	7	0.5 x 2.0	13 x 51.5 = 669
5	7	1.0 x 1.5	26 x 38 = 988
6	8	1.0 x 2.0	26 x 51.5 = 1339
7	8	1.5 x 1.5	38 x 38 = 1444
8	9	1.5 x 2.0	38 x 51.5 = 1957

The dimensions of the portal are determined from the equality (f/F) x 100 = 11.2%, where 11.2% (see table 1) corresponds to a pipe height of 8 m (conditional height, approximate calculation) and a rectangular pipe cross-section.

F = (f x 100): 11.2 = (338 x 100) : 11.2 = 3017cm 2 . We take the width of the portal (size A) to be 63 cm. Then the height of the portal (size B) will be equal to: B = F: A = 3017: 63 = 47.9 cm. Finally, we can take the height of the portal B = 49 cm (7 rows brickwork). Experienced master can assess the condition of the brick pipe, its quality indicators and, based on the results, decide to lower size B by a row, taking B = 42 cm.

In this case, you can double-check your solution:

1. F = 63 x 49 = 3087 cm 2, (f x 100): F = 338 x 100: 3087 = 10.9%, only 0.3% less than the table.
2. F = 63 x 42 = 2646 cm 2, 338 x 100: 2646 = 12.7%, which is 1.5% higher than the table. Preference should be given to the first option. But the option with a “margin” of 1.5% can be justified in the case of a low assessment of the pipe’s condition.

Let us add that the dimensions of the portals in both examples meet the requirements of the “standard series”, the concept of which is defined below.

A detailed analysis of the diagram and table 1, as well as their practical application, shows that Swedish experts have included a certain safety factor in their recommendations and that the use of this diagram in practical work guarantees good results.

Why is this safety factor needed? Let's try to figure it out using a specific example.

Let's take two fireplaces with equal characteristics for calculation. The fireplace portals (F = A x B) are the same, the pipes are the same height with the same cross-section. However, the designs of the fireplaces are different: the first fireplace is classic (a pipe above the firebox of the fireplace), the second has a pipe located behind the back wall of the fireplace (Finnish type of fireplace). The chimney of the second fireplace has deviations from the vertical, although the axle joints are in accordance with the recommendations and amount to no more than 30 o. Both pipes are brick, the first with smooth internal walls; in the second, unlike the first, the inner surface of the pipe is poorly smoothed.

Comparing the options, any specialist will give preference to the first fireplace. However, calculating both options will give the same result. This is explained by the introduction of a safety factor into the calculation methodology in order to ensure the performance of the worst case scenario.

The conclusion is simple: if you are dealing with an “ideal” option, or more precisely, with a fireplace in which the pipe is close to “ideal” (Chapter 4), then relaxations in the calculation are permissible. The f/F values ​​can be taken less than those indicated in the table by 1% (for example, instead of the recommended 10%, take 9% into account, i.e. underestimate the table recommendations by 1%). In the worst case scenario, it is better to take this value 1% more than the table one. Those. a difference in f/F values ​​of up to 2% is possible. The indicated range of 2% (+1.0%) can be considered a tolerance for the use of this calculation method.

We will carry out calculations for fireplaces of the standard range.

Let us first define the concept of a standard series. The concept of a "standard course" should not be confused with brickwork courses. Any window in brickwork must have dimensions that are multiples of the width and height of the brick. It is not surprising that the same imported devices, for example, Finnish ones, manufactured to national brick standards, cause inconvenience for our stove makers in their practical use. It is better to take the dimensions of the fireplace portal A and B as multiples of half the length of the brick (for size A) and the height of the brick 6.5 cm (for size B). In this case, it is necessary to take into account the requirements for the thickness of the seams - 0.5 cm, i.e. The height multiplicity will be 7 cm.

In this case, dimensions A will be as follows (including seams): 50.5-51 cm (2 bricks); 63 cm (2.5 bricks); 76.5-77 cm (3 bricks); 90 cm (3.5 bricks); 102 cm (4 bricks); 114-115 cm (4.5 bricks) and so on.

The height of the portal (size B) is a multiple of 7 cm, starting from 42 cm (6 rows); 49 cm (7 rows); 56 cm (8 rows), 63 cm (9 rows), etc.

Note that the standard row is adopted for the convenience of laying not only the portal, but also the entire fireplace body. In individual, justified cases, the rule of the standard series may be violated. In this case, the rows of brickwork that follow above the firebox ceiling, for example, to the fireplace table and the back wall of the fireplace body, will have non-standard (non-standard) masonry.

Let's decide on the masonry brick pipes standard row (Fig. 3.4), consider the laying of pipes Nos. 1-8, even and odd rows are given. The pipework of 4 bricks has been crossed out, unsuitable for fireplaces due to the small flow area.

Rice. 3.4.
Brick pipes for fireplaces (No. 1-8 satisfy the work of all fireplaces from small A = 51 cm, to the largest: A = 1.5-2 m

The proposed row of pipes is made up of a whole number of bricks (5, 6, 7, 8, 9). The use of brick halves is undesirable, because represents additional labor intensity in the preparation and laying of pipes, therefore the halves are excluded from the proposed series. Laying pipes from 6, 7 and 8 bricks is given in 2 options. By using only whole bricks, the range of pipes recommended for use is narrowed to the possible limit. Practice shows that this range of brick pipes can completely satisfy the proposed range of fireplaces with portals (windows) of the standard range. Let us summarize the parameters of these pipes in Table 2.

Table 2. Indicators of pipes No. 1-8

№	Bricks	Flow section in bricks	Calculation of cross-sectional area taking into account seams f, cm 2
1	5	0.5 x 1.0	13 x 26 = 338
2	5	1.0 x 1.0	26 x 26 = 676
3 *	6	0.5 x 1.5	13 x 38 = 494
4 *	7	0.5 x 2.0	13 x 51.5 = 669
5	7	1.0 x 1.5	26 x 38 = 988
6	8	1.0 x 2.0	26 x 51.5 = 1339
7	8	1.5 x 1.5	38 x 38 = 1444
8	9	1.5 x 2.0	38 x 51.5 = 1957

The brick pipes shown in Fig. 3.4, can, in turn, be sorted into 4 groups according to the geometry of the flow section (taking into account the aspect ratio):

1. Preferred group, square tubes (1:1 aspect ratio): No. 2 and No. 7. This group has its own curve on the diagram.
2. Rectangular pipes with an aspect ratio of 1.0:1.5 and 1.5:2.0 - No. 5 and No. 8, the third curve in the diagram belongs to this group.
3. Rectangular pipes with an aspect ratio of 0.5:1.0 - No. 1 and No. 6.
4. Rectangular pipes with an aspect ratio of 0.5:1.5 and 0.5:2.0 - No. 3 and No. 4.

The most unfavorable aspect ratio is in the fourth group (pipes nos. 3 and 4) and significantly better in the third group (nos. 1 and 6). Both of these groups stand out from the diagram and, strictly speaking, should take a place somewhat to the right of the third curve, which is not reflected in the diagram. The practice of using the diagram shows that when calculating pipes according to the 3rd group (pipes No. 1 and No. 6), it can be attributed to the third curve on the diagram and at the same time apply the tolerance (relaxation) mentioned above to the calculation.

When calculating pipes according to the 4th group (No. 3 and No. 4), they can also be classified as the third curve, but the relaxation in the calculations should not be applied to them. For this reason, in Table 2 these pipes are highlighted (marked with asterisks).

At this point we can summarize preliminary results regarding our readiness to carry out fireplace calculations.

1. Fireplaces of the standard range have been determined: the widths of the portals have been established (dimensions A), which, together with the heights of the portals (dimensions B), fully characterize fireplaces starting from A = 51 cm and B = 42 cm. Design solutions and recommendations for individual elements of fireplaces: portal, firebox, smoke collector , the body and other parts of the fireplace are given in the chapter “Design solutions”.
2. The ratios of the flow area of ​​the pipes to the area of ​​the fireplace portal are specified (Table 1), taking into account the recommendations of the diagram (Fig. 3.1).
3. There are 8 categories of standard brick fireplace chimneys: with square and rectangular sections (Fig. 3.4 and Table 2). Below, Table 3 shows a standard range of round pipes. Thus, taking into account the named tables (2 and 3), practically any possible option for fireplace pipes (brick, prefabricated, metal) becomes covered for calculation and application.
4. Two examples of fireplace calculations are given. Calculations come down to selecting the parameters of a pipe to a given fireplace portal, taking into account the required height (example 1) or, conversely, selecting a fireplace portal to a given (previously installed) pipe (example 2).

Table 3. Round pipes

At this point, the issues of fireplace calculations could be closed, because the calculation principles are clear and all the initial data for the calculations are established. However, it must be taken into account that most of the performers (this number often includes experienced stove makers) prefer to use ready-made tables. To compile them, calculations were carried out for the entire standard range of fireplaces, taking into account the listed pipe sections. The calculation results are summarized in a single (summary) table.

Table 4. Results of fireplace calculations

Fireplaces		Pipes for fireplaces (three types)
Portal window		Round section		Rectangular section		Square section
Ah, cm	V, cm	Diameter, mm	Height H, m		Height H, m.	Flow section in bricks No. tr.	Height H, m.
51	42	180	4.6	№ 1 0.5 x 1.0	4.0	X	X
	49		6.5		4.7	X	X
	56		9.3		6.8	X	X
	63		13.5		9.5	X	X
	56	200	5.5	X	X	X	X
	63		7,3	X	X	X	X
	70		10.0	X	X	X	X
63	42		4.3	№ 1 0.5 x 1.0	5.5	X	X
	49		6.8		7.2	X	X
	56		9.4		12.0	X	X
	63		13.5	X	X	X	X
	56	220	5.5	№ 3 0.5 x 1.5	4.5	X	X
	63		8.0		5.7	X	X
	70		10.5		8.0	X	X
	77		14.0		10.0	X	X
77	49		7.0		5.3	X	X
	56		9.7		7.5	X	X
	63		14.0		10.0	X	X
	63	250	6.8	№ 4 0.5 x 2.0	4.6	X	X
	70		9.0		6.0	№ 2 1.0 x 1.0	5.0
	77		12.0		8.0		6.5
	84	X	X		10.0		8.2
90	70	300	5.0	X	X		7.7
	77		6.7	№ 5 1.0 x 1.5	4.5		10.0
	84		8.0		5.2		13.0
	91		11.0		6.5	X	X
	98		13.0		8.0	X	X
	105		X		9.5	X	X
102	77		9.5	X	X	X	X
	84		10.3	X	X	X	X
	91		16.0	X	X	X	X
	98	X	X	№ 6 1.0 x 2.0	5.0	X	X
	105	X	X		6.0	X	X
	112	X	X		7.0	№ 7 1.5 x 1.5	4.9
	119	X	X		8.3		6.0
	126	X	X		9.8		7.0
114	105	X	X		8.0		5.6
	112	X	X		9.6		6.8
	119	X	X		11.0		8.0
	126	X	X	X	X		9.3

Let us comment on the summary table (Table 4) and show how its indicators are best used in practice.

But first let us draw the reader’s attention to the main thing: The summary table lists fireplaces with portals and pipes to them (with different cross-sectional geometries). The contractor is given the opportunity (using a summary table) to select a fireplace and a pipe for it. How best to implement the selected indicators into a specific fireplace with a chimney is discussed in Chapter 4 (about pipes) and Chapter 5 (about fireplaces).

1. The table summarizes the calculation results, which are reflected in more detail in 3 tables located in the appendix.
2. All indicators in the table (including pipe dimensions) are the main dimensions of the fireplaces presented, i.e. belong to the first category. However, real fireplaces are characterized by two more groups of sizes: structural (second category) and other sizes (third category). Recommendations for the second category of sizes are given in “calculation of fireplaces”
3. Are the recommended pipe dimensions (section and height) unconditional? No. When preparing a project, you should make an independent assessment of the future pipe: assess how close it will be to the “ideal” pipe option or how far from it it will be, and on this basis you can make independent adjustments to the final result of the calculation. Typical for this part is example 6 in the “Non-standard solutions” section. In this particular case, the use of an “ideal” pipe made it possible to significantly deviate from the table one (the correction was 1.2%). However, this recommendation should be used with a certain degree of caution (calculation corrections of no more than 1% are acceptable); inexperienced performers should not use it at all.
4. For greater confidence, whenever preparing a project, it is better to double-check the f/F (%) calculation and compare the result with the indicators in Table 1 or with the diagram in Fig. 3.1. The tables in the appendix should be considered as auxiliary to summary table 4. These tables also provide reference information (it is marked with an asterisk, the following are indicated: the dimensions of the portal A and B, the flow section of the pipe, as well as its area f and % f/F), which can be used use to double-check the results. The calculation results of these tables correspond to summary table 4. Rechecking is carried out in the same way as shown in the calculation example (see example 2).
5. In Fig. 3.2 shows the nomogram of the SCHIDEL company. The nomogram is intended for calculating “ideal” pipes (Schidel chimneys belong to this category of pipes). In other non-standard cases, for example, when the axis of the SCHIDEL chimney is broken, it is necessary to carry out recalculations. In our conditions, in such cases it is better to refer to the Swedish diagram.

Analysis and comparison of the results confirms the above that the Swedish diagram (unlike the nomogram) was created with the expectation of use in a wider range and was supposed to cover unfavorable options that may occur in practical work. This explains the success of its use in domestic practice.

The nomogram (Fig. 3.2, second half) is also very useful. It reflects the cross-section of the channel necessary to take air from outside and supply it to the combustion zone (or to the room to replace the air flowing into the fireplace) for normal operation of the fireplace.

Example, a fireplace with A=63 cm, B=49 cm, a room with an area of ​​18 m2 and a height of 2.75 m. The portal area is 0.63 x 0.49 = 0.3 m2. Room volume 18 x 2.75 = 49.5 m3. The required channel cross-section (according to the nomogram) is 100 cm 2.

In practice, when building such a fireplace, for example, in a country house, you may not attach importance to this issue. In this case, the air consumption of the fireplace will be compensated by the flow of outside air through the cracks in window frames and through other leaks in the construction of doors, walls, ceilings, etc. the house itself. A completely different picture in cottages, where there are leaks, especially in modern window blocks, practically absent. This problem is solved by installing an air intake channel with a cross-section of 13x13 cm, which can be closed (adjusted) with a valve. It is possible to supply such channels directly to the combustion zone of the fireplace or next to the fireplace. The nomogram shows that for large fireplaces such a cross-section may be clearly insufficient. When designing fireplaces (especially large fireplaces) intended for operation in the specified conditions, the issue of air intake from the outside and its supply to the fireplace should be given special importance, because it will affect the operation of the fireplace. One should also expect interaction between the operation of the fireplace and the ventilation device of a given room, which is usually an integral part of the ventilation system of the entire house.

The calculation results (Table 4) are comparable with the data from other tables that are recommended for use and are widely used in practice. To do this, we will use the book of the famous author V.M. Kolevatov “Stoves and fireplaces”. The book contains four tables from different sources: one Swedish and English and two German tables.

1. Dimensions A of all four tables, like other recommended sizes, do not correspond to the concept of our “standard series,” which causes problems for the performer. For example, the task: how to fold a pipe with a flow section: 200 x 200 or 200 x 330 mm.
2. Each size A corresponds to only one size B, which unjustifiably limits the list of recommended fireplaces (there are no more than seven of them in all four tables). For comparison, the proposed summary table 4 shows almost the entire range of standard fireplaces used (with portal sizes from A = 51-114 cm and B = 42-126 cm) with three pipe sections and their heights.
3. Design dimensions are present in each table. The dangers of this approach were discussed above.
4. Through pipes:

a) the Swedish version makes reference to the diagram, but does not show how to use it;
b) in the English version, only rectangular and square pipe sections are specified, close to our brick pipes; nothing is said about round pipe sections. No indication of pipe heights is given;
c) in the first German version, pipes of rectangular, square and round sections are specified, but also without indicating the heights of the pipes. The sizes of pipes, especially brick ones, are inconvenient for our practice. All specified pipe sections are overestimated;
d) in the second German version (the only one of the four), the pipe heights are divided: up to 5 meters and 5-10 meters. However, the dimensions of pipe sections 200 x 200 and 300 x 300 are present, the inconvenience of their use has already been mentioned.

2.How to determine in advance the functionality of the fireplace.

The question of the functionality of the future fireplace should concern the contractor, because It is he who is responsible for the work as a whole and, most importantly, for its final results. Fireplace inspection should be part of preparatory stage along with the issue of linking the fireplace project to a specific place (we omit other issues of preparing for the start of work). Both questions: checking the functionality and tying the fireplace to a place are difficult to separate, because practically aimed at solving a single problem.

Solving the issue of tying a fireplace to a place, more often and, as a rule, comes down to finding a non-standard solution for the fireplace pipe; these issues are discussed in Chapters 4 and 9. Each responsible person, even in cases where he has to deal with the model (standard size) of the fireplace, has previously repeatedly tested in practice, you need to make it a rule to double-check the fireplace that is to be installed in a new place.

And this is explained by the fact that, in almost 8 cases out of 10, planning decisions require a non-standard approach and new solutions for the pipe, as has already been mentioned. New design pipes (whether it be: a new geometry of the internal section, the presence or absence of an insert in it, a new height of the pipe, additional breaks in the pipe axis, the presence of a smoke chamber, etc.) will significantly, in a new way, affect the operation of the fireplace. All this has been said above, and these factors cannot be ignored.

An option is possible when the customer insists on a specific choice of a finished project. In this case, checking the fireplace by the contractor is absolutely necessary. And it is possible that for the selected project you will have to make “your own,” a new pipe to replace the one specified in the project. Let us repeat: it is not the mythical author of the project, about whom nothing is known, who is responsible for the final result, but its performer. It is he who, in such cases, acts as an expert “with the right of a decisive vote” in assessing the project proposed to him for execution.

Let us demonstrate such a check using two typical examples. The check is very simple and requires minimal time.

The fireplace data given below is recommended for implementation and, at first glance, should not raise any doubts.

Open brick fireplace, fireplace portal: A = 69 cm, B = 65 cm. Fireplace pipe No. 1 (five, in stove terminology, with internal section dimensions: 26 x 13 cm), pipe height (H) is not specified.

And the second fireplace: A = 76 cm, B = 49 cm. Pipe No. 1, height is also not specified.

Checking the first fireplace:

F = 69 x 65 = 4485 cm 2 (portal area).
f = 26 x 13 = 338 cm 2 (pipe cross-sectional area). f/F = (338: 4485) x 100 = 7.5%

Checking the second fireplace:

F = 76 x 49 = 3724 cm2.
f = 26x 13 = 338 cm 2.
f/F = (338: 3724) x 100 = 9.0%

We reconcile the calculation results (7.5% and 9.0%) using the diagram (Fig. 3.1).

It turns out that the first fireplace is generally outside the operational zone; even a 20 m high pipe cannot save it. The remedy for its treatment is one of two things: replacing the pipe or reducing the fireplace portal.

The second fireplace is saved by an “atypical” pipe of 12.5 m in height. The best option is to switch to a pipe with a larger cross-section. This fireplace belongs to the category of medium fireplaces (A = 77 cm), it has a low portal height (49 cm is small for an average fireplace, but keep in mind that this is a matter of taste). This example confirms what was said in the appendix (see appendix 15, group of medium fireplaces): middle group fireplaces requires switching to brick pipe No. 2. And under these conditions, lowering the height of the portal becomes pointless.

However, and we emphasize this, both fireplaces are recommended as tested, and we will not question the very fact of the tests carried out by the authors. Mystery? No. Quite often you can see similar fireplaces with deviations from the norm shown in the diagram. Both examples are from this series; they, unfortunately, are typical of our practice. The very fact of checking the operation of such fireplaces after the completion of its construction cannot serve as a real argument for the correct conclusions.

It is fireplaces with such deviations (sometimes even smaller ones) that operate unstably and, as they say, smoke at the first opportunity. For example, poor draft associated with weather conditions, or soot deposits, which will soon reduce the pipe cross-section, etc. (the reasons may be different, and the main reason is an incorrectly selected fireplace pipe).

This category also has implicit, barely perceptible signs. For example, the first light, almost imperceptible signs of burning may appear in the air during the operation of the fireplace, which cannot be eliminated even with the damper fully open. This sign is often controversial, because at the initial stage, it is better felt only by people with a well-developed sense of smell. The “problem” can be easily resolved when there is a margin in the valve position.

It is clear that such “fine tuning” when operating fireplaces classified as “lame” is usually out of the question.

And finally, the third problem. If the conditions for connecting a fireplace require non-standard decisions to be made on the pipe, then we must not forget that overcoming the additional resistance that will appear in the “non-standard pipe” will also require additional draft costs in the pipe. As a result, they will be detrimental to the operation of the fireplace itself.

You need to understand that physically there is no clear limit-norm in the form of the specified %, when you can assure that crossing this limit immediately ensures smoking and complete inoperability of the fireplace. This border is blurred, so the transition from a favorable zone to a dangerous zone is almost imperceptible. We can say that fireplaces in this understanding have a wide range of conditional performance. This is provided that the signs mentioned above are considered insignificant and allow, for example, a slight amount of smoke from the portal overlap. Note that sometimes some fans even like this picture with a lightly smoked portal.

Only getting into a zone close to favorable for the operation of the fireplace can give positive results. Therefore, resolving the issue of acceptable tolerance for recommendations and methods for increasing the efficiency of fireplace pipes, guaranteeing high-quality operation of fireplaces, is of utmost importance. The boundary in question has been established (it cannot be otherwise), it is indicated by curves on the diagram and specific numbers in the summary table (as well as in auxiliary tables) and it is better not to cross the designated boundary. It’s “dangerous” there - that’s the conclusion a novice specialist (and not just beginners!) should draw.

Only an experienced specialist who understands the essence of the issue can find the possibility of crossing this boundary consciously, and not “at random” (as well as when selecting a pipe). This is one of the components of the master’s professionalism.

It is compliance with the standards laid down by Swedish researchers that is the best guarantee fireplace performance. Let us add that the described methodology and the quality of work of fireplaces made according to the specified standards have been tested many times in domestic practice.

Regarding the fireplace project, which was considered first, other comments can be made: neither size A nor size B fit into the norms of the standard series, which in advance, already at the design stage, promises future inconveniences in the work for the performer of this project. And in this regard, we note that it would be logical to compare the obtained results of testing the given example with the data tables 4, but the fireplaces of the standard range were used there, so I had to refer to the diagram. Let's imagine a situation: the customer insists on these two projects. What should a performer do? This has already been said above, the performer needs to offer “his” pipe, this is pipe No. 2, if necessary, you need to find a non-standard solution for connecting it. And secondly, it is possible to make small changes to fireplace designs, which should not significantly affect their appearance. Keeping in mind that the customer, as a rule, makes his choice of fireplace based on its appearance. And one last thing. There are practically no projects or really unfavorable fireplaces, the functionality of which could not be restored; the task lies more in choosing the optimal, most economical solution, suitable for specific conditions. This is what is discussed in Chap. 10, which is based on practical examples.

This is the source of heat that we expect, even if the fireplace was built for purely aesthetic purposes. And before building a fireplace, the first thing we do is calculate all the necessary parameters of the fireplace: its size, depth, chimney height, cross-section of the smoke duct opening, firebox power, etc.

It is a mistake to think that if a fireplace is decorative, then you can use any one. The fireplace burns oxygen, and, for example, taking a powerful fireplace for small room, you can get problems in the operation of the fireplace and constantly open windows. The size of the hole for the chimney, its height and the material of the firebox and fireplace lining, the location of the fireplace and other factors play a role.

What parameters are important to consider before choosing and building a fireplace?

• Fireplace power . Directly depends on the size of the room. More precisely, its volume, since the volume is heated, not the area of ​​the room. Good insulation of the house allows you to reduce power indicators. The standard calculation is 1 kW of fireplace power per 20 cubic meters. room area for poorly insulated houses in cold climates. With good insulation, 1 kW will heat 35 cubic meters. premises.
• Firebox size . The rated power of the fireplace depends on it. The area of ​​the opening for the firebox correlates with the area of ​​the room as 1 to 50. Let's assume the area of ​​the room is 30 square meters. m. 1\50th part of 30 sq.m. is 0.6 sq.m., or 6000 sq.cm.
• Width And height The fireboxes are related as 2 to 3. Solving a simple proportion, we get 2x + 3x = 0.6, x = 0.12. We take the width of the firebox equal to 0.24 m, height - 0.36 m.
• Combustion hole depth . It determines how much heat will get inside the room, and how much will go into the wall or adjacent room. The depth of the opening for the firebox is 2/3 of the height. In our example - 36 cm*2\3 = 24 cm.
• For those who are not fans of calculations, we present table of finished sizes for some standard room areas, in cm

Fireplace elements per sq.m. premises
Portal width
Portal height
Firebox depth
Height of the rear wall of the firebox
Firebox rear wall width
Smoke collector height
Section of a chimney with rough walls
Section of a chimney with smooth walls

• Calculation chimney parameters - a difficult concept for an amateur. If possible, it is better to leave it to professionals. An incorrect calculation leads to a lack of draft or even reverse draft: when the products of fuel combustion go into the room instead of the chimney and poison its inhabitants. Excessive draft will lead to excessive consumption of firewood and a decrease in the efficiency of the fireplace and the oxygen content in the room. Basic rules - the chimney pipe should not be less than 5 meters, and should be 50 cm higher than the highest point (ridge) of the roof. The chimney opening is 10-15 times smaller than the combustion opening.
• Firebox material . It is worth considering that cast iron is warmer than steel and heats the space 70% faster. Clay retains heat well and releases it for a long time: therefore, ceramic stoves are the warmest. Among the intermediate options are granite, marble, shell rock and other facing materials. They take a long time to warm up, but they also give off heat for quite a long time.
• Additional functions : Adjusting the draft allows the fuel to burn (hence release heat) longer. The double afterburning function uses fuel combustion products for additional heating.
• Fireplace location . It is not taken into account in last place. If the fireplace and chimney are adjacent to street wall, then all the cats in the area will be grateful to you: lion's share the heat will go outside. Wall fireplace can heat an adjacent room, and a corner one can heat 2 at once, if its power is sufficient and the area of ​​the rooms does not exceed 20 sq.m. The island fireplace only operates at its destination.

Assortment of wood-burning fireboxes from Saga. Fireplaces"

Inexpensive fireboxes

Wood burning firebox Cheminees Diffusion A 1 - French firebox with a power of 14 kW, weight 82 kg, dimensions (WxHxD) - 690x696x351 mm.

The Cheminees Diffusion A 2.2 Etanche firebox is a cast iron firebox with a power of 12 kW, the same dimensions as the previous model, without raising the glass.

Wood burning firebox Cheminees Philippe B 1-2 with damper - cast iron assembly body, rotary damper to increase fuel burning time, power 12 kW, weight 112 kg, WxHxD - 695x770x415 mm.

Wood-burning firebox Cheminees Diffusion C 6 - firebox with a nominal power of 15 kW, WxHxD - 770x880x504 mm, weight 143 kg, with the function of adjusting the combustion air supply and a flame cutter-deflector to increase the efficiency of the fireplace.

Cheminees Diffusion B 5-2 firebox with turbine - cast iron firebox with a nominal power of 10 kW, equipped with a retractable ash box, side-opening glass with a self-cleaning function, 2 two-speed fans and 2 nozzles for forced convection. Supports long burning mode.

Nowadays, people’s desire for a comfortable life is understandable and explainable. Owners of houses outside the city, cottages, and summer cottages strive to make their home cozy, full of a warm atmosphere, so that visiting it is a pleasure at any time. And nothing can compare with a modern fireplace, which in the winter cold will give you the opportunity to warm up and enjoy the process of smoldering logs in the hearth.

However, before installing it, you initially need to decide on a number of issues that relate to the choice of fireplace insert and its installation. The quality of its heating, as well as heating costs, depend on which device will be installed in the room.

Why is choosing a fireplace insert important?

This is great if you are wondering which fireplace insert to choose. You are on the path to making the right choice. The choice is important because the combustion chamber can perform a variety of functions. Because of this they are used:

• or as the main source of home heat;
• or as additional heating for housing;
• or as a decorative element.

If you choose a combustion chamber, you should initially proceed from its main purpose.

Let's say, if you need the device as an interior decoration, and not as a heating device, then it would be illogical to buy a high-power fireplace for a huge amount. And vice versa, if the fireplace is supposed to be assigned an important heating function, then it is first of all necessary to study its technical characteristics that will help it perform its tasks well.

What types of fireplace inserts are there?

Before considering the combustion chambers, it is necessary to remember what the fireplace generally consists of. This is the chimney pipe, the outer cladding part and the combustion chamber itself.

Highlight:

• fireplace with open hearth;
• fireplace with closed firebox.

The first type of design is the most comfortable and romantic. It’s always a pleasure to spend time in front of an open fire on a cool evening and admire the burning of wood in the hearth. However, it is worth remembering that this option has several disadvantages:

1. Firstly, it is an increased danger. Such a fireplace should not be left unattended.
2. Secondly, low efficiency. About 15% of the heat energy remains in the room, and the rest, unfortunately, is removed through the smoke exhaust ducts.

We can conclude that a fireplace with an open combustion chamber is purely a decorative luxury that allows you to create a warm and cozy atmosphere in a residential area. Plus, it will not be possible to adjust the fuel combustion power in such a device.

Adjustment can only be made with a view, which allows you to open or close the chimney damper and control the draft. This fireplace will not be effective as a heating system.

In contrast, a fireplace with a closed combustion chamber will be highly effective in heating homes outside the city in winter and in the off-season. It will be entrusted not only with the function of decoration, but also with heating the room.

The high efficiency and good performance of these models is caused by a completely different operating principle compared to the device open type. Thermal energy accumulates inside the combustion chamber and is not removed with decay products to the outside. This ensures high thermal efficiency. If the fireplace is installed according to the rules, the efficiency of the device can reach 92%.

Another advantage of a fireplace with a closed firebox is that it is equipped with a long-burning system, due to which heat energy can be stored for 12 to 15 hours on a single load of fuel. This is both effective and quite economical. You can adjust the oxygen supply, which affects the combustion force, using the knob.

Such a system does not require constant control by the owner; the fireplace will independently and slowly emit heat, and in the morning the optimal temperature and atmosphere will remain.

The following points are also considered to be the distinctive parameters of closed fireplace inserts:

1. Good savings in fuel consumption due to high coefficient useful action.
2. Stable work.
3. Insensitivity to drafts and sudden wind gusts.
4. Larger product range compared to open-type fireboxes.
5. Possibility to repair the structure without dismantling the fireplace.
6. Long service life.
7. The combustion of the heated area is almost zero, since the fire does not enter directly into the room.
8. Safe use. You can leave the fireplace and go to bed without worrying about the possibility of a fire.
9. Combustion control option by regulating the air supply to the fireplace.
10. If desired, you can find a fireplace with minimal weight on the market.
11. The ash accumulates in a specially designated niche, so it does not stain the heated area.
12. Compared to an open firebox, a closed one does not require certain parameters for smoke exhaust ducts, which is due to the design itself.

As for the disadvantages, we can highlight the narrow glass in inexpensive models, which does not allow you to enjoy the view of the flame.

If desired, it is possible to convert an open fireplace insert into a closed one. To work, you will need to insert a closed cast iron firebox into general design fireplace.

The combustion chamber itself is a fireplace insert (cassette), which is closed with a glass door. This liner is installed to the chimney pipe, from where combustion products are later removed.

Pros and cons of cast iron fireboxes

Having decided on the type of fireplace combustion structure, it is necessary to select the chamber material. The firebox can be cast iron or steel, or can be lined fireclay bricks. Compared to steel construction, cast iron combustion chambers are much cheaper and are also more practical. Which is better is not even worth thinking about.

Cast iron fireplace inserts are characterized by:

• fire resistance;
• resistance to deformation;
• ease of installation;
• low cost;
• high efficiency;
• excellent thermal conductivity;
• chamber tightness;
• ability to heat a room up to 300 m²;
• ability to retain heat for a long time.

The special design of the closed-type cast-iron combustion chamber allows you to retain heat energy for a long time and transfers up to 70% of the heat into the room.

The outside of the combustion chamber is coated with a special protective paint that can withstand temperatures up to 700 °C. The front side has a glass door, which allows you to observe the intensity of combustion and also load firewood.

The lower part has an ash chamber. Combustion products are sent here, namely tar, ash and ash. An ash pan is also necessary for another process. It is well known that combustion cannot occur without oxygen. Air circulates through the ash niche into the cast iron firebox.

The disadvantages of fireplace inserts for cast iron fireplaces with glass include:

1. Poor visibility of observation windows.
2. Rapid contamination of windows with soot.
3. All designs are available only in black, and this does not allow you to choose the design of this fireplace.

However, the last point can be easily corrected by installing a decorative grille on the fireplace in the form of, for example, a bronze openwork mesh.

Choosing a fireplace insert

Once you have decided on the design features and material of the combustion chamber, all that remains is to choose a model. The main parameters based on which you need to choose a cast iron firebox are:

1. Power.
2. Door material.
3. Combustion chamber shape.
4. Glass door shape.
5. Price.

The dimensions of the fireplace insert may vary. It all depends on the manufacturing company and many other parameters.

Power

This parameter becomes decisive in the rationality of purchasing the equipment itself. For the right choice fireplace according to this parameter, it is necessary to calculate the volume of the heated room, plus - to decide whether the fireplace will serve as the main source of heat in the home, or will simply be a backup heater.

The power characteristics of the combustion chamber are indicated depending on its weight, dimensions, and material.

The required power of the equipment is calculated based on the footage of the room. Premises with an area of ​​50 to 100 m² require a combustion chamber with a power of 7 to 11 kW. For larger areas, you need to use the formula of 1 kW of power per 10 m² of heated room.

If you cannot choose one of several models based on this characteristic, then take the firebox with the lowest rating. In practice, the heating capacity of the device is higher than prescribed, so in the model with the lowest power, fuel will be used more efficiently.

Door material

The door is the most important part of the combustion chamber. In order for it to withstand elevated temperatures of 750-8000 °C, it is made of quartz refractory glass or ceramic crystal.

Fireplaces with transparent glass doors are made from refractory ceramics. While options with cloudy glass with a yellowish tint are made from quartz fireproof glass.

Currently, market offers are replete with inexpensive models with compact glass doors, but if you wish, you can also buy more expensive fireboxes, with double-leaf and convex glass doors. Of course, the difference is only in the decorative functions, because it is much more pleasant to enjoy smoldering firewood when the fireplace is equipped with a combustion chamber with a glass door big size. Modern fireboxes have doors with an automatic glass cleaning function. Due to the circulation of warm air, it is easy to wipe the glass from dust, soot and soot.

Combustion chamber shape

The shape of the combustion chambers is:

1. Corner fireplace inserts.
2. Standard / frontal.

Here the choice, of course, depends on the location of the device. The frontal version is also divided into “trapezoid” and “rectangle”.

Dignity standard design also lies in its budget cost and high efficiency.

This is due to the fact that the chimney is located directly with the firebox, without any bends; the draft in this fireplace is better. A corner fireplace insert, in turn, does not have similar performance due to the remote location of the smoke exhaust pipes.

Glass door shape

According to the shape of the glass door:

1. Rounded.
2. Flat.
3. Segmental.

It is logical that the firebox with a flat door is considered the cheapest. However, if you want to make the design of the room more unusual, you can purchase interesting options round type.

On the market you can find universal type doors, in which one part is made of steel, decorated decorative elements forging, and the view behind the flame is provided by a part made of glass.

Such a style solution for the window will make it possible to add a special cozy and vintage touch to the design.

Price

How much a wood-burning fireplace insert will cost directly depends on the quality of the glass. It is necessary to take the process of selecting this product responsibly. It can have one layer or many.

It is also worth remembering such characteristics as service life and heat resistance. The technical data sheet of the device always states a guarantee of use (by the hour). The heat resistance of a window directly depends on its strength - this indicator is written down in the data sheet (in millimeters).

In terms of price/quality ratio, it is rational to purchase glass with a thickness of 4 mm.

How to increase the efficiency of a fireplace with an open hearth?

As mentioned above, a fireplace with an open firebox allows you to create a comfortable and romantic atmosphere for socializing and spending time indoors. This design feature facilitates air exchange in the room and makes it possible to observe the fire. And if you follow all the rules, the fireplace will be quite safe in terms of safety.

At the same time, it is irrational to operate it as a heating device. The maximum thermal efficiency of an open combustion chamber is 15-20%. In addition, the inability to heat using convection means that the fireplace only heats nearby objects and interior parts (ceiling, walls, floor). You can feel comfortable only very close to the fireplace. And if after a certain time there is a need to use an open firebox as a heating device, then you need to carry out specific works for its installation.

To fully understand the need to convert an existing fireplace into a highly efficient device, it is necessary to understand what that open firebox is and what processes take place inside it when burning logs.

Now pay attention.

It is impossible to achieve highly efficient combustion of wood in an open firebox.

Since cool air circulating into the combustion chamber from the room greatly reduces the combustion temperature. It turns out that during the pyrolysis process the wood does not completely disintegrate, and in addition to the ash, coals also remain.

Due to the low temperature at the top of the combustion chamber, high-quality oxidation of volatile hydrocarbons does not occur.

Incomplete oxidation produces harmful carbon monoxide and low-temperature water vapor. The smoke gases that enter the chimney contain unburned wood particles - soot, ash and are characterized by a low temperature of 100 ° C. Due to the low temperature of the smoke gases, condensation appears.

And if there is no appropriate thermal insulation at the top of the chimney, the pipe slowly collapses. The efficiency of open-type fireboxes is maximum 15-20% of the theoretically possible volume of heat energy contained in wood.

To convert a real open firebox into a highly efficient heating device, you need:

1. Make the temperature in the combustion chamber higher by dosing warm air into the firebox: 25% air into the lower part of the structure for the pyrolysis process and 75% air into the upper part of the structure for the oxidation of hydrocarbon bonds.
2. Provide convection in the room, which will transfer warm air from the firebox and direct cool air from the room into the firebox.

Due to the fact that the combustion chamber is of an open type during combustion, it needs large volume air, to eliminate drafts in the room, it is necessary to supply air into the firebox from outside.

This issue can be rationally resolved only by purchasing a convection cassette for the existing firebox.

To prevent the movement of air from the room directly into the chimney, the distance between the cassette and the open firebox must be insulated. When burning in a closed cassette, the temperature in the upper part of the structure will reach 700-750 °C. Secondary air masses that pass between the walls of the combustion chamber will move up the structure and effectively oxidize the hydrocarbon bonds released during pyrolysis. With the help of built-in cassettes, the air in the room is heated with sufficient efficiency through convection currents.

When burning wood in a closed cassette, the temperature of the smoke gases circulating into the chimney is 250-300 °C, this in turn prevents the formation of water vapor.

Purchasing a closed cassette with convection channels for installation in an open combustion chamber makes it possible to increase the heat transfer of the fireplace by up to 60-70% and turns it into a relatively efficient heating device.

Currently, the range of these products on the Russian market is quite large. And it’s not difficult to choose exactly the model that will meet all the user’s requirements. All that remains is to decide on the material for making the firebox, be aware of each type of equipment, its features, advantages and disadvantages, plus do not forget about specifications and shape. All this was discussed above. Good luck with your choice!

teplofan.ru

Traction

Air enters the firebox through the fireplace portal (window). It is believed that to ensure proper operation heating device, the speed of air movement through the portal must be at least 0.25 m/sec.

In practice, it is difficult to measure the speed value. Before lighting the fireplace, you can only determine whether there is draft or not by the deflection of the flame of the lit paper. How good or bad the draft (air flow speed) is, the user of the fireplace is convinced in practice by the smell of burning (smoke in the room) and the rate of combustion of the wood.

The draft is influenced by many parameters, including the temperature inside and outside the room, the degree of heating of the flue gases, the condition of the chimney (the presence or absence of cracks in it through which additional air is sucked into the pipe), the type, quantity and humidity of the fuel.

But the most important condition for the proper operation of the fireplace, ensuring its functioning within a wide range of variable parameters, is compliance with the basic dimensions and their ratios in the design of the heating device.

The main dimensions of the fireplace structure include the height (B), width (A) of the fireplace window and its area (F), height (Htr), dimensions of the passage section, cross-sectional area of ​​the chimney (f). Of course, all these sizes can be different, but a certain ratio must be maintained between them, otherwise the fireplace will not be able to work.

It does not determine the performance of the fireplace, but the depth of the firebox © and the dimensions that determine the position of its side walls significantly affect the efficiency of its operation. No less than the parameters of the firebox, the efficiency of the fireplace is influenced by the size and position of the fireplace tooth (protrusion), the height of the beginning of the protrusion from the fireplace hearth (L), the excess of the tooth level above the upper border of the fireplace window (G), the width of the pipe opening not blocked by the fireplace projection (M).

The remaining dimensions of the fireplace do not affect its performance and efficiency. The shape of the fireplace, the dimensions of the body, and the position of the fireplace table (mantel) should be chosen based on how harmoniously the fireplace fits into the overall interior of the room.

In the article “Fireplace Design” it was already mentioned that the window area of ​​the fireplace portal is chosen depending on the volume of the room in which it is installed, namely, the number square meters The window area should be 20 times less than the number of cubic meters of room volume. Based on the selected dimensions of the fireplace window, calculate the cross-sectional area of ​​the pipe to be at least 1/16 of the portal area. If the fireplace is attached to an already finished chimney, then, based on the required ratios, the calculation is carried out on the basis of the dimensions of the finished chimney, from which the permissible parameters of the fireplace window are calculated.

The above reasoning and relationships are basically correct, but they do not take into account important parameters - the height of the chimney and the shape of its cross-section.

The cross-section of the chimney can be round, square or rectangular. Smoke (fireplace gases) does not rise vertically through the chimney, but in ascending spiral-shaped flows. In a round pipe, the shape of the flow corresponds to the shape of the pipe; its entire space is occupied by a single upward flow of gases.

In pipes with a square cross-section, vortices are formed at the corners, directed against the main flow of gases; as a result, the upward movement of smoke does not occur over the entire cross-sectional area of ​​the pipe, but only in its center, which practically leads to a decrease in the effective cross-section of the pipe. The vortices formed in rectangular pipes interfere even more with the upward movement.

Due to the reduction in the effective cross-section of the pipe depending on the shape, round, square and rectangular pipes, having the same proportions in relation to the portal area, remove smoke from the fireplace with different efficiency.

Accurate engineering calculation of the parameters of a chimney is a task more likely for a theorist than for a practitioner, requiring not only the consideration of many variable parameters, but also the possession of certain special knowledge in heating engineering.

In practice, they usually use average tables and diagrams calculated by specialists. Various specialized companies offer calculations of chimneys in relation to their own products, so the exact values ​​of “branded” parameters may vary.

The figure shows a diagram developed by the German company Shiedel, connecting the diameter of a round chimney of its own production with the height of the chimney and the area of ​​the open fireplace portal.

The following diagram makes it easier to select the height of a pipe with different opening geometries, depending on the ratio of the portal area and the cross-section of the chimney opening.

As can be seen from the graph, the difference in the pipe height required to provide traction at the same values ​​of the ratio of the portal area and cross-section is quite significant. In practice, the ratio is chosen depending on the diameter of the pipe available, and when building brick pipes, they are guided by the dimensions of the opening lined with whole full-size bricks.

Another factor influencing the final height of the chimney is the placement of the chimney outlet above the roof. When the pipe is located near the ridge of the roof (up to 1.5 m), the upper cut of the chimney should be located at least 50 cm above the ridge. At a distance of 1.5-3 m, it should not fall below the ridge. At a distance of more than 3 m, the angle between the horizontal line passing through the ridge and the line connecting it with the upper cut of the pipe cannot exceed 10°. If you neglect the recommendations, the draft will be significantly reduced by the air flow formed by the atmospheric wind blowing from the opposite roof slope.

The values ​​of the pipe height and the relationship between the pipe cross-section and the portal area given in the tables and diagrams are not absolute. The difference in numbers obtained from different sources is due to the fact that there are no clear boundaries between a fireplace that works correctly or with some minor flaws. In addition, as already noted, the efficiency of the fireplace is influenced by other factors, not just geometric dimensions. Therefore, it is practically impossible to determine (especially before the start of operation) how ideally the heating device will work.

If there are doubts about the appropriateness of a particular figure, the best adviser is personal experience. Unfortunately, the home master usually does not have it, so it is impossible to do without consulting a professional.

We thank the RETRO company for their assistance in preparing the material. The RETRO company carries out a full range of stove work, manufacturing, repairing, and restoring stoves and fireplaces.

www.diy.ru

Interior decoration

Nowadays, fireplaces have become very popular; they are installed not only in private homes. Modern biofireplaces have made it possible to use this unit in ordinary apartments. But such designs are intended primarily for decorative purposes; today we want to talk about real ones that work for wood fuel, the installation of which requires the construction of a foundation.

It warms and dries

Regardless of what kind of fireplace is installed in the house, many perceive it as an attribute of room decoration and do not think about why this unit has been preserved almost unchanged from ancient times to the present day. But it is an excellent home ventilation device.

With its help, you can ventilate and dry the room, and this operation is performed in a very short time, during which more than one heating device will not be able to cope with this task. This unit is very good to use in rooms where there is no central, constant heating.

For example, by lighting a fireplace in a private house used for occasional residence, you will very quickly dry out and warm up the cottage. (See Stove-fireplace for a summer residence)

Size matters

But you need to understand that all these advantages are effective only if the sizes of fireplaces for your home are chosen correctly. It’s no secret that when arranging it, many care primarily about the appearance and location in the room. And only lastly do they pay attention to such an important fact as the size of the fireplace.

Today we’ll talk about how to correctly calculate a fireplace for your home and make a design drawing based on the existing tasks to ensure maximum efficiency.

Important aspects: what to consider?

When you start designing a fireplace for your home, you need to make a drawing (See Drawings of corner fireplaces) and perform calculations based on the size of the room. Firewood can be burned either in a special metal basket or on a grate, or perhaps simply on the bottom of the firebox.

Our regular readers know that for normal combustion, in addition to fuel, a sufficient supply of air is necessary.

• in the case when the fuel burns on a flat hearth and the dimensions of the fireplace inserts are the same, combustion on a grate will be much more efficient;
• in both cases the dimensions will be identical.

The fact is that the use of a grate provides additional air flow; in this case, you can reduce the size of the firebox without losing efficiency.

Double effect - warmth plus ventilation

Since we are talking about air supply and the possibility of its intake different ways, it should be added that in some cases, air can be taken not only from the room in which the fireplace is located, but also from the next room or even from the basement.

This device allows you to achieve several positive aspects at the same time:

1. By taking air from the basement, you will significantly increase its ventilation, which in itself is a good result.
2. If air is taken from another room of the house, a vacuum is not created in the room where the fireplace is located, and its absence does not allow cold air from outside to enter the heated room. The effect is obvious - the room warms up very quickly with minimal fuel consumption.
3. If you need to ventilate a heated room, simply shut off the external air intake. In this case, the air for combustion begins to come from the room where it is located, and the room is ventilated.

We carry out calculations

But we didn't answer main question— how to calculate the size of the fireplace and make a drawing?

First of all, the combustion hole

First of all, you need to determine the size of the fireplace insert. To accurately calculate the size of the firebox, you need to measure the room in which the fireplace will be installed. Let's start by determining the size of the firebox opening. The ratio of the combustion opening to the area of ​​the room is 1:50 .

To make it more clear, let’s take a room of a certain size and calculate correct sizes fireplaces that can be installed in it.

1. The area of ​​the room is 20 m².
2. We carry out the calculation – 20/50=0.4 m², or 4000 cm², we have decided on the size of the firebox opening, this data can be entered into our drawing.

Defining width and height

• In our case it turns out 51X77 cm or 510X770 mm.
• It's quite easy to double-check this data. 51Х77 =3927 cm2, almost 4000 cm2, as we see, our calculations coincide with the requirements.

The important part is depth

1. Depth is 2/3 of height.
2. We already know the height, it is equal to 510 mm.
3. Let's do the calculation – (510/3)*2=340 mm – we have determined the depth.

This depth is ideal for a fireplace of this size.

• if you increase the depth, the heat will simply begin to fly out into the chimney;
• Reducing this size will lead to smoke in the room.

For those who, for some reason, do not want to carry out all the measurements and calculations themselves, below we provide a table of the main parameters that will help make the drawing. Using them, knowing the area of ​​the room, you can determine the standard dimensions of the fireplace that you require.

Chimney - special attention

When designing, it is important to correctly calculate the size of the chimney for the fireplace. It is calculated based on the area of ​​the portal and should be in 10-15 times less than it.

Advice: knowing the dimensions of fireplace inserts, you can, of course, calculate the size of the chimney, but you should know that this is a very important undertaking. If you do not have much experience in this area, it is better to entrust it to a professional, because no one has canceled such a concept as reverse thrust. Carbon monoxide poisoning is deadly! Remember this!

You can obtain more detailed information about chimneys by reading the relevant articles on our portal. Various chimneys, including fireplace chimneys, are described in detail there.

Dimensions and material - direct relationship

When setting up a fireplace, the dimensions of the chimney and firebox are not the only ones you need to know. For example, someone is more interested in the question - how many bricks do you need for a fireplace? The question is not idle and quite understandable.

But before we answer it, we want to add a little to all of the above. In our article, when considering methods for calculating and determining the dimensions of a particular part, we did not mention materials. Why are we talking about this only now? Because this is directly related to the question of the number of bricks.

Selection of location and dimensions

Previously, we calculated the firebox dimensions; the fireplace and its dimensions directly depend on the material from which it will be made. Knowing the material, you can quite accurately calculate the dimensions and determine the location for the future fireplace.

On our pages we have already described how to choose a place, so we will not repeat ourselves. The only thing you need to add: knowing the placement rules and correctly calculating the dimensions, you can install this unit in the best possible way.

Foundation

After determining the dimensions of the firebox and chimney, you should calculate what the foundation should be.

The foundation is built based on the weight of the future structure. If the weight of the fireplace is less than 700 kg, then there is no need to make a foundation, however, often the weight of the structure is significantly higher, so a foundation is necessary.

When building a medium-sized fireplace, as a rule, a foundation is made with a depth of 0.75 to 1 meter. These figures are valid if you plan to live in the house permanently and the soil underneath will not freeze. When building a fireplace on summer cottage, the foundation must be buried to the depth of soil freezing.

Please note: it is extremely important that the foundation of the fireplace and the foundation of the house are free of bandages, as these structures may have different settlements, which will lead to the formation of cracks.

Basic mistakes

Unfortunately, this does not always happen. In some cases, one or several rules are violated:

1. The right size fireplace for a specific room.
2. Proper placement in compliance with its dimensions for a specific room.

Knowledge is power

This knowledge is not necessary if you do construction with your own hands; it will also be useful to you when you hire outside workers for construction.

Nowadays, there are “specialists” who are able to build something that at first glance looks and works well, but upon closer examination turns out to be just another flaw. Knowledge will help you perform proper supervision of construction work in your home.

Number of bricks - counting orders

As for the quantity of bricks, we will not give detailed calculations for one simple reason - they will not be useful to you at all. Indeed, for each specific case a completely different calculation is required.

Nevertheless, we will try to explain in a nutshell how you can approximately determine the amount of brick. Knowing the dimensions of the fireplace, the dimensions of the brick and the thickness of the seam, you can quite accurately calculate its quantity.

1. In any case, when arranging fireplaces, its dimensions are transferred to orders of magnitude.
2. Having the orders in hand, use them to count the number of bricks.
3. Don't forget about the seams. The thickness of the seam in this case plays an important role.

We have already described how to properly arrange seams in articles about masonry on our resource, so we will not repeat ourselves. Adding up the number of bricks in all orders, you get total. If the base is made of brick, do not forget about it.

Our advice: add more bricks to the received amount 10% .

Put it together

Having made a drawing of a fireplace, you are probably convinced that compliance with the basic parameters is extremely important when constructing it, and appearance plays a secondary role in this case.

sdelaikamin.ru

Conditions for normal traction

Everyone has heard of the term cravings. Even without knowing the definition, you can intuitively imagine what it is. There are opinions that this is a pressure difference or temperature difference between the upper and lower points of the chimney.

However, this idea is not entirely correct, because with a small pressure difference, thrust can be increased due to other factors. Therefore, draft should be understood as the speed of movement of air masses through the cross section of the chimney. It may be increased, decreased or normal. The average speed should be 0.25 m/s.

It is impossible to measure the speed of movement of combustion products at home. Before lighting the fireplace, it is recommended to make sure that there is draft. To do this, you should observe the behavior of the flame of a burning piece of paper, and the magnitude of this draft can already be assessed by the behavior of the fireplace itself after kindling.

Brick laying scheme

In order not to rely on chance, all factors influencing the amount of thrust are carefully studied. Among them are dynamic (atmospheric pressure, precipitation, wind, damage to the chimney) and statistical, depending on what dimensions of the fireplace were chosen during construction, what its width and height are.

Basic fixed dimensions

Standardization of sizes does not mean that all fireplaces should be cloned from one. The fact is that among all the dimensions, those that affect its functionality are determined. These are the dimensions that must be observed. Among them stand out linear dimensions fireboxes, area of ​​the smoke channel, distance from the floor to the bottom edge of the fireplace window, position of the smoke tooth relative to the fireplace hearth, width of the channel in the area where the tooth overlaps.

The remaining sizes do not affect the work and play a decisive role in distinguishing models from each other. For example, the dimensions of the portal are selected depending on the size of the firebox opening and the space allocated for the fireplace.

Fixing dimensions does not mean setting their absolute value. The listed dimensions depend on the volume of the room that will have to be heated. But a mathematical relationship has been established between them, which cannot be violated. When creating a project, you can use one of the many ready-made tables, which indicate all the values ​​necessary for these conditions. This table is an everyday tool for any craftsman.

Dimensions of fireplace elements

Despite the fact that such tables can be found in any source, every master, even a beginner, should have an idea of ​​how to generate this data.

Calculation of parameters

The starting point for calculating the structure can be the volume of the room or its area. To determine the area of ​​the fireplace window, which is the front part of the firebox, you need to divide the area of ​​the room by 50. It is possible to carry out all the necessary measurements for the house without special instruments. Knowing the area of ​​the combustion hole, you will have to solve a small math problem. The ratio of the width and height of the window is expressed as a fraction 2/3. Based on these conditions, the first specific dimensions are determined.

Theoretically, the speed of gas flow should not depend on the depth of the firebox. But practice shows absolutely opposite results.

• Excessive depth leads to increased speed. This outcome is considered unfavorable, since the heat will not have time to be transferred into the room and, along with warm air will leave the room through the chimney.
• The shallow depth of the firebox is the direct cause of poor draft. The room will gradually begin to fill with combustion products.

The standard depth is tied to the height of the window. It is 2/3 of the latter value. The selected proportions have been tested over the years and are the truth, to which there is no need to select a theory.

Ready cast iron option

A complete calculation of the fireplace involves calculating the parameters for the chimney. But here the main indicators depend on the shape of the smoke channel. In cross section, the channel can be a circle, square or rectangle.

Convection currents rise up the chimney along a complex trajectory that looks like a spiral. As a result, in a circular channel, air masses practically do not encounter obstacles. In the other two types of channels, microflows are formed in the corners, which, with their turbulence, prevent the movement of smoke. In such chimneys, it is advisable to talk about an effective channel, with an area much smaller than the area of ​​the smoke opening.

This theory is proof of the fact that with the same height of the chimney, the amount of draft depends on the cross-sectional shape of the channel. Average chimney parameters can be set and adhered to during construction. The length of the pipe will be affected by where it exits through the roof. What is important here is not compliance with proportions, but the distance from the pipe to the ridge. If it varies within 1.5 m, then the pipe is erected 0.5 m higher than the top point of the roof.

Table based on chimney dimensions

The next range of distances, limited to three meters, corresponds to the equality of the levels of the pipe and the ridge. When the distance from the pipe to the ridge exceeds 3 m, it is necessary to apply geometric constructions. Mentally draw a horizontal line through the highest point of the roof. From it, count an angle of 10° degrees and draw a beam. Our pipe should end at the intersection of the beam and the axis of the smoke channel.

We should not forget about the area of ​​the canal. It should be 10 times smaller than the area of ​​the fireplace window. If you make a channel with a larger area, this will not lead to an increase in traction, as it might seem at first glance. Too large an area contributes to the breakthrough of cold air flows from the atmosphere into the room. This phenomenon is called backdraft.

What hasn't been taken into account yet

All the dimensions that were listed above are in a certain dependence on each other. We proposed taking the area of ​​the room as the starting point for the calculation, which is a completely reasonable decision. However, in some cases the problem has to be solved from the end. For example, if the house has a chimney, which in its functions meets the requirements for fireplaces. Then all calculations will have to start from the channel area.

There are certain indicators that are not related by a mathematical relationship, but are decisive for the normal operation of the fireplace.

• The height of the fireplace window from the floor can be about 0.3-0.4 m (depending on the presence of a niche for storing firewood).
• The podium for the portal protrudes from its borders in front by 0.5 m, and on the sides by 0.3 m.
• The angle of the smoke tooth is 20° degrees.
• The side walls of the firebox taper towards the chimney, forming an angle with the normal from 45° to 60° degrees.

Now you know everything about shaping the geometric dimensions of the fireplace. Is it more convenient to use this knowledge or ready-made tables to understand what the width of the fireplace and its height should be? Each master gives a personal answer to this question.

Most owners of private houses dream of installing a stylish, romantic and cozy piece of furniture - a fireplace, the size of which largely depends on what function it will perform - heating or decorative.

A living fire is fraught not only with beauty, but also with a high probability of a fire, so laying a fireplace must be preceded by careful calculation.

How to calculate the dimensions of a fireplace?

A fireplace often serves as a full-fledged source of heat (even if it’s an auxiliary one and not the main one). The dimensions of this heating structure for a room with an area of ​​20 m2 are as follows:

• the firebox area should vary within 0.4 m2;
• combustion hole height - 52 cm, width - 78 cm;
• the depth of the hearth should be 34-35 cm.

The cross-sectional area and height of the chimney are equally important values ​​that require separate and especially careful calculations. A fireplace whose dimensions are calculated incorrectly can cause a real threat to human health and life, which lies in the possibility of combustion products and carbon monoxide. Optimal ratio The cross-sectional area of ​​the chimney and fuel hole is considered to be 1/10, however, the standard size of the fireplace is not an axiom, since each individual case requires an individual accurate calculation.

Sizing Wood Fireplaces

Wood-burning fireplaces are structures in which all family members often and with pleasure gather during cold autumn and winter evenings. The sound of crackling firewood and the sight of dancing flames inevitably create a unique atmosphere of calm and comfort. Real brick fireplaces are not a cheap pleasure, so many home craftsmen want to do this work themselves. Of course, this activity cannot be called simple, but if everything is done in accordance with the rules, the result will definitely be positive.

The fireplace includes the following required components:

• firebox;
• smoke chamber;
• chimney.

The size of each element must have the required ratio with the dimensions of the heated room.

So, for example, the area of ​​the combustion hole in relation to the total area of ​​the room should be 1:50. In this case, the height and width have a ratio of 2:3, and the depth and height of the firebox varies from 1:2 to 2:3.

The size of the smoke hole is most influenced by the combustion area. The required level of draft can be ensured as follows: the firebox area should be 8-15 times larger than the cross-sectional area of ​​the chimney pipe. Moreover, if installation is planned round pipe, then you can choose a smaller cross-section than if the chimney were square or rectangular.

Material selection

Wood-burning fireplaces are best built from red solid wood

The quality of this material can be checked by the following indicators:

• the color should be uniform and thick;
• the blow of a hammer on a brick should “return” with a ringing and clear sound.

In addition, you will need:

• sand, the grain size of which should not exceed 1.5 mm;
• Cambrian clay, and you can also use brown or dark red;
• crushed stone - 3-6 mm;
• Portland cement grade 300.

You also need to purchase:

• smoke damper;
• fireplace screen;
• grate.

Foundation

Before you start building home, you need to take care of a separate foundation. The depth of the pit should be 60 cm, and the width should be 10 cm greater than the dimensions of the future foundation.

The bottom should be covered with crushed stone and compacted thoroughly to maintain horizontality.

The installed formwork must be backfilled broken brick, stones or crushed stone, and then fill with thoroughly mixed cement mortar. The top of the foundation should be leveled and checked for levelness. After 7 days, you can begin building the fireplace.

Features of fireplace masonry

Before starting the construction of such a useful invention as a fireplace, the dimensions of which were determined by us earlier, waterproofing should be provided. To do this, you will need roofing felt laid in 2 layers. Laying should start from the corners. In this case, you need to constantly monitor the level. To give the design original look, you can lay the bottom row on the edge, and all subsequent ones - flat. External continuous rows require the use of a trowel or trowel. The smoke collector or firebox should be done manually, as this helps to detect small pebbles in the solution.

It is important to remember that when constructing a smoke collector and firebox, a fireplace stove requires removing excess mortar with a damp cloth. We must not forget that the inner wall is not plastered. The seam must be thin, otherwise it can quickly crack. Modern fireplaces need ligation of seams half a brick in each row.

The lining of the firebox and the outer wall should not be connected, otherwise, due to frequent temperature changes, damage to the masonry may occur.

About modern fireplaces

Every person enjoys hearing the sound of crackling wood and feeling the warmth of a flame. Similar feelings can be enjoyed not only in nature, but also in own home. Brick fireplaces can make dreams come true. The main tasks of this equipment include not only creating comfort and coziness in the home, but also heating it.

Modern fireplaces can consume as fuel:

• coal;
• natural wood;
• electrical energy.

There are many ready-made fireplaces on the market. The difference is made between open and closed types of fireboxes. In addition, the fireplace stove can have a closed combined heating system or an open one, where the type of firebox directly depends on the wishes of the buyer.

A modern fireplace is a versatile and practical design that can be installed in any convenient place.

Fireplace as a design element

The fireplace is wonderful design solution, capable of emphasizing general style rooms. For its design, modern, country or any other style pleasing to the owner can be used.

Heating with a fireplace requires accessories such as a poker, tongs, ash scoop and grate. True, modern society pays much more attention to the emotional and psychological role of this structure. That is why it is not recommended to install a fireplace in a small room, near a door or in a passage. The ideal option is comfortable chairs located in a spacious room, a special stand for equipment and a neat bench for your feet.

or rustic: unpretentiousness against the backdrop of modest charm

The etymology of the word “rustic” speaks of the most characteristic features of this style - deliberate “rudeness”, “roughness”, stylization for a rustic interior (this style is also called country). The desire of our ancestors to introduce an element of aesthetics into the arrangement of their primitive home gave rise to this architectural trend, which subsequently began to develop so widely and comprehensively.

Country style is characterized by natural details, components and materials, emphatically “rough” processing and an open shape of the hearth. The most suitable materials are: shell rock, sandstone, tuff stone, etc.

About the refined excesses of a baroque fireplace

Originating in Europe in the Middle Ages, it is a reflection of taste in the architecture of the Renaissance. This direction is also appropriate in such a matter as fireplace styles. It is distinguished by: dynamic image, excessive pomp and luxury, a certain illusion of forms and lines, pomp and decorativeness.

Art Nouveau style

Lovers of the Art Nouveau style will easily abandon most decorative elements in favor of an unusual color experiment. This direction is characterized by: elongation, pencil-shaped design, a constructive combination of stone and metal parts, as well as the presence of ceramics or glass in the cladding. Style adherents are unusual geometric shapes, restraint, conciseness, as well as non-traditional Constructive decisions. Worthy accompaniments to an Art Nouveau fireplace include a large abstract or landscape painting, minimally decorated furniture, walls covered in asymmetrical lines and a muted color scheme.

Not every person knows that all types of fireplaces, represented by a huge number of models, according to some technical parameters have well-defined, established standard indicators. These parameters include the dimensions of the main node elements. When constructing a fireplace, you should adhere to these values, since deviations can lead to disruption of the functions of the device. Any fireplace must cope with the same tasks:

• remove heat resulting from fuel combustion;
• ensure removal of combustion products;
• provide oxygen supply to the furnace.

Drawing of a wall fireplace

The history of fireplace construction is rich in experimental discoveries that accumulated in the form of experience that was passed on from the master to his student. Today, many professional stove makers do not even think about why the chosen standard project has fixed dimensions. His knowledge comes down to memorizing indicators for different types of stoves. Meanwhile, there are quite good reasons for standardization. Let's study in more detail the dimensions of the fireplace, its main characteristics, which are an indicator of its proper operation.

Conditions for normal traction

Everyone has heard of the term cravings. Even without knowing the definition, you can intuitively imagine what it is. There are opinions that this is a pressure difference or temperature difference between the upper and lower points of the chimney.

However, this idea is not entirely correct, because with a small pressure difference, thrust can be increased due to other factors. Therefore, draft should be understood as the speed of movement of air masses through the cross section of the chimney. It may be increased, decreased or normal. The average speed should be 0.25 m/s.

It is impossible to measure the speed of movement of combustion products at home. Before lighting the fireplace, it is recommended to make sure that there is draft. To do this, you should observe the behavior of the flame of a burning piece of paper, and you can already estimate the magnitude of this thrust by the behavior.

Brick laying scheme

In order not to rely on chance, all factors influencing the amount of thrust are carefully studied. Among them are dynamic (atmospheric pressure, precipitation, wind, damage to the chimney) and statistical, depending on what dimensions of the fireplace were chosen during construction, what its width and height are.

Basic fixed dimensions

Standardization of sizes does not mean that all fireplaces should be cloned from one. The fact is that among all the dimensions, those that affect its functionality are determined. These are the dimensions that must be observed. Among them are the linear dimensions of the firebox, the area of ​​the smoke channel, the distance from the floor to the bottom edge of the fireplace window, the position of the smoke tooth relative to the fireplace hearth, and the width of the channel in the area where the tooth overlaps.

The remaining sizes do not affect the work and play a decisive role in distinguishing models from each other. For example, the dimensions of the portal are selected depending on the size of the firebox opening and the space allocated for the fireplace.

Fixing dimensions does not mean setting their absolute value. The listed dimensions depend on the volume of the room that will have to be heated. But a mathematical relationship has been established between them, which cannot be violated. When creating a project, you can use one of the many ready-made tables, which indicate all the values ​​necessary for these conditions. This table is an everyday tool for any craftsman.

Dimensions of fireplace elements

Despite the fact that such tables can be found in any source, every master, even a beginner, should have an idea of ​​how to generate this data.

Calculation of parameters

The starting point for calculating the structure can be the volume of the room or its area. To determine the area of ​​the fireplace window, which is the front part of the firebox, you need to divide the area of ​​the room by 50. It is possible to carry out all the necessary measurements for the house without special instruments. Knowing the area of ​​the combustion hole, you will have to solve a small math problem. The ratio of the width and height of the window is expressed as a fraction 2/3. Based on these conditions, the first specific dimensions are determined.

Theoretically, the speed of gas flow should not depend on the depth of the firebox. But practice shows absolutely opposite results.

• Excessive depth leads to increased speed. This outcome is considered unfavorable, since the heat will not have time to be transferred into the room and, together with the warm air, will leave the room through the chimney.
• The shallow depth of the firebox is the direct cause of poor draft. The room will gradually begin to fill with combustion products.

The standard depth is tied to the height of the window. It is 2/3 of the latter value. The selected proportions have been tested over the years and are the truth, to which there is no need to select a theory.

Ready cast iron option

A complete calculation of the fireplace involves calculating the parameters for the chimney. But here the main indicators depend on the shape of the smoke channel. In cross section, the channel can be a circle, square or rectangle.

Convection currents rise up the chimney along a complex trajectory that looks like a spiral. As a result, in a circular channel, air masses practically do not encounter obstacles. In the other two types of channels, microflows are formed in the corners, which, with their turbulence, prevent the movement of smoke. In such chimneys, it is advisable to talk about an effective channel, with an area much smaller than the area of ​​the smoke opening.

This theory is proof of the fact that with the same height of the chimney, the amount of draft depends on the cross-sectional shape of the channel. Average chimney parameters can be set and adhered to during construction. The length of the pipe will be affected by where it exits through the roof. What is important here is not compliance with proportions, but the distance from the pipe to the ridge. If it varies within 1.5 m, then the pipe is erected 0.5 m higher than the top point of the roof.

Table based on chimney dimensions

The next range of distances, limited to three meters, corresponds to the equality of the levels of the pipe and the ridge. When the distance from the pipe to the ridge exceeds 3 m, it is necessary to apply geometric constructions. Mentally draw a horizontal line through the highest point of the roof. From it, count an angle of 10° degrees and draw a beam. Our pipe should end at the intersection of the beam and the axis of the smoke channel.

We should not forget about the area of ​​the canal. It should be 10 times smaller than the area of ​​the fireplace window. If you make a channel with a larger area, this will not lead to an increase in traction, as it might seem at first glance. Too large an area contributes to the breakthrough of cold air flows from the atmosphere into the room. This phenomenon is called.

What hasn't been taken into account yet

All the dimensions that were listed above are in a certain dependence on each other. We proposed taking the area of ​​the room as the starting point for the calculation, which is a completely reasonable decision. However, in some cases the problem has to be solved from the end. For example, if the house has a chimney, which in its functions meets the requirements for fireplaces. Then all calculations will have to start from the channel area.

There are certain indicators that are not related by a mathematical relationship, but are decisive for the normal operation of the fireplace.

• The height of the fireplace window from the floor can be about 0.3-0.4 m (depending on the presence of a niche for storing firewood).
• The podium for the portal protrudes from its borders in front by 0.5 m, and on the sides by 0.3 m.
• The angle of the smoke tooth is 20° degrees.
• The side walls of the firebox taper towards the chimney, forming an angle with the normal from 45° to 60° degrees.

Now you know everything about shaping the geometric dimensions of the fireplace. Is it more convenient to use this knowledge or ready-made tables to understand what the width of the fireplace and its height should be? Each master gives a personal answer to this question.