Exhaust ventilation duct in a private house. How to calculate natural ventilation

Chimneys are divided according to their design and location:

• on wall chimneys - installed inside solid brick walls
• main chimneys - laid out in the form of a free-standing brick riser
• mounted chimneys - installed directly on stoves

If the room has solid stone walls, then the device interior walls New chimneys are the most convenient and economical, since they do not require additional building materials and are laid out simultaneously with the walls.

Primary requirements

For each furnace, as a rule, a separate chimney or duct (hereinafter referred to as the pipe) should be provided. Since when two stoves are fired simultaneously, the stove on the lower floor, with a stronger draft, will interrupt the top one, preventing the free exit of smoke from it.

It is allowed to use a common chimney for two stoves installed on the same floor, provided that a cut is installed in the form of a transverse wall between the chimneys at a height of at least 75 cm. In this case, the minimum cross-sectional size of the common chimney channel must be at least 1x0.5 bricks.

In houses with stove heating not allowed:
a) device exhaust ventilation with artificial inducement, not compensated by influx with artificial inducement
b) removal of smoke into ventilation ducts and installation of ventilation grilles on smoke ducts

Chimneys should be located in the internal walls of the building. Laying them in external walls is less economical and creates difficulties during operation. Passing through chimneys in the outer wall, the gases give off some of the heat unheated room, and in the atmosphere due to low temperature atmospheric air the gases are cooled excessively, which impairs traction. At the same time, tarry substances are released from the gases, which penetrate through the masonry and are deposited on the external structure of the house.

If the chimney riser is forced to be located in an external wall, the chimney wall must be thickened. Thickening of the wall is done in the form of pilasters (square or rectangular projections on the wall).

Minimum thickness masonry between the chimney and the outer surface of the wall is taken depending on the design temperature of the outside air:

• at t=-20°C and above - 38 cm (1.5 bricks)
• from t=-20°С to t=-30°С – 51 cm (2 bricks)
• from t=-30°С and below - 65 cm (2.5 bricks)

For laying the foundations of stoves, hearths and chimneys, the same materials are used as for the foundations of a house; for the main masonry of stoves, hearths, chimneys and channels in the walls - ordinary clay brick (solid).

If the walls are made of sand-lime brick, cinder blocks, etc., areas with smoke channels should be laid out of ordinary (solid) clay red brick.

Smoke pipes (ducts) or chimneys for stoves

The height of chimneys placed at a distance equal to or greater than the height continuous construction protruding above the roof should be taken:

• not less than 500 mm - above flat roof
• not less than 500 mm - above the roof ridge or parapet when the pipe is located at a distance of up to 1.5 m from the ridge or parapet
• not lower than the ridge of the roof or parapet - when the chimney is located at a distance of 1.5 to 3 m from the ridge or parapet
• not lower than a line drawn from the ridge downwards at an angle of 10 to the horizontal - when the chimney is located from the ridge at a distance of more than 3 m

It is allowed to connect two stoves to one pipe, located in the same apartment on the same floor. Such placement may be allowed in exceptional cases, provided that the wall is insulated with outside by thickening the masonry or protecting it with heat-insulating, fireproof materials (the method of insulation must be provided for in the design).

Then the distance between the outer surface of the walls and the nearest inner surface of the channel is taken to be at least 640 mm (2.5 bricks). When connecting pipes, cuts should be made with a thickness of 0.12 m and a height of at least 1 m from the bottom of the pipe connection.

When the chimney is located in the middle of the room, the walls are laid out 1/2 brick thick, and when located near the cold outer wall buildings - a whole brick. The thickness of the walls of chimneys or smoke channels at their junction with metal or reinforced concrete beams should be taken as 130 mm.

The thickness of the walls of the channels in the internal stone walls, as well as the thickness of the partitions (cuts) between the smoke and ventilation ducts must be at least 120 mm. Stoves, as a rule, should be placed near internal walls and partitions made of non-combustible materials, providing for their use to accommodate smoke ducts.

Smoke ducts may be placed in external walls made of non-combustible materials, insulated, if necessary, on the outside to prevent moisture condensation from the exhaust gases.

In the absence of walls in which smoke ducts can be placed, mounted or root chimneys should be used to remove smoke. Chimneys should be made vertical without ledges from clay bricks with walls no less than 120 mm thick or from heat-resistant concrete no less than 60 mm thick, with pockets 250 mm deep at their bases with cleaning holes closed by doors.

The internal surfaces of chimneys should be smoother without mortar leaks in the seams and carelessly laid bricks. The chimney must be free of slopes and turns.
It is allowed to accept deviations of round chimneys at an angle of up to 30° to the vertical, with a deviation of no more than 1 m. Sloping areas must be smooth, of constant cross-section, with an area not less than the cross-sectional area of ​​the vertical sections.

Experience shows that the cross-section of the chimney is from 1/10 to 1/12, and in more favorable cases up to 1/15 of the clear size of the combustion opening. In all cases, the cross-section of the chimney (if two stoves are connected to one pipe) must be at least 14x27 cm.

Brick chimneys

The cross-sectional area of ​​rectangular chimneys (smoke ducts) depending on the thermal power of the furnace according to SNiP 2.01.01-82 should be taken as no less than:

• 140x140 mm - with a furnace thermal power of up to 3.5 kW
• 140x200 mm - with a thermal power of the furnace from 3.5 kW to 5.2 kW
• 140x270 mm - with a thermal power of the furnace from 5.2 kW to 7 kW

The cross-sectional areas of channels in brick chimneys must be multiples of the width of the brick. The mouths of brick chimneys to a height of 0.2 m should be protected from precipitation. Installation of umbrellas, deflectors and other nozzles on smoke brick pipes not allowed.

Round asbestos-cement, ceramic or metal chimneys

The cross-sectional area of ​​round smoke ducts must be no less than the area of ​​the indicated rectangular ducts. Metal chimneys must be removed from combustible roof structures by 700 mm. In this case, within the attic, the pipes are insulated with a layer of asbestos at least 3 mm thick and plastered over a mesh cement mortar, and in places of passage through a combustible roof they are additionally equipped with special devices in the form of sandboxes.

Smoke outlets round pipes and the ventilation ducts located next to them in the walls are made with a slope of at least 60° to the horizon and a laying (attitude) of no more than 1 m. To connect stoves to chimneys, it is allowed to provide branch pipes with a length of no more than 0.4 m, provided:
a) the distance from the top of the pipe to the ceiling made of flammable materials must be at least 0.5 m if the ceiling is not protected from fire and at least 0.4 m if there is protection;
b) the distance from the bottom of the pipe to the floor made of flammable or slow-burning materials must be at least 0.14 m.

The pipes should be made of non-combustible materials, providing a fire resistance limit of 0.75 hours. and more. Smoke in the stove often occurs when the mouth of the pipe is blown out by a strong wind. To prevent this phenomenon, it is necessary to check the condition of the windproof device (deflector) above the head of the chimney, and if there is no device, install it.

For deflector options, see Fig.

Chimneys on buildings with roofs made of combustible materials should be equipped with spark arresters. For reasons fire safety A spark arrester is installed on the head in the form of a cap with a blank lid and wire mesh on the sides with a mesh size of no more than 3 mm.

You should know that weather vanes and deflectors can be installed on round pipes for solid fuel stoves. When burning gas, they CANNOT be installed, as water vapor condenses on them. This may cause ice dams to form.

For gasified furnaces, umbrellas of a simplified design are installed on the heads of round pipes. If the walls of the pipe are subsequently plastered or insulated with asbestos-cement slabs, then it is permissible to lay out the head 1/2 brick thick.

Smoke pipes (channels) for fireplaces

The main difference between a fireplace and a stove is the much larger cross-section for air access to the firebox, which is why large masses of air are sucked into the fireplace, which causes a decrease in the temperature in the flue (compared to stoves). Therefore, the traction force in a fireplace per 1 linear meter of flue height is less than in a stove.

To create normal draft, the height of the fireplace chimney must be correspondingly greater than that of the stove. To ensure sufficient draft during operation, it is IMPORTANT that the flue gases are cooled minimally as they move through the chimney.

The cornice formed in the narrow section of the chimney (the so-called smoke tooth) plays important role and has a dual purpose. During the combustion process, it retains the cooled gases descending along the rear (colder) wall, preventing them from passing into the combustion space, because this may cause the rod to tip over.

Cold gases retained by the eaves are picked up by a stream of hotter gas flowing from the narrow section of the chimney that forms the front wall of the fireplace and the edge of the “tooth”, and are carried into the overlying chimney.

The second purpose of the cornice is to collect falling soot deposits. In the immediate vicinity of the ledge with inside install a cleaning door through which the chimney is periodically cleaned. A damper is installed in the neck at the level of the chimney cornice to regulate the draft and disconnect the fireplace from the chimney. To reduce heat loss, the walls of the fireplace chimney must be of sufficient thickness.

The most harmful effect on draft is caused by atmospheric air leaks into the chimney through leaks in the masonry, as well as non-working stoves connected to a common chimney, i.e. The chimney for the fireplace must be separate from all other ducts. All leaks must be identified and eliminated.

The next condition maintaining normal draft (without describing the hydraulic properties of draft) is to install a chimney with a cross-section round shape, then comes square and finally rectangular. This is explained by the fact that in right angles the movement of gases is difficult and, moreover, soot is often deposited in them.

Therefore, it is best to use asbestos-cement or ceramic pipes for installing chimneys. Due to the difficulty of fitting to the fireplace chimney, chimneys are most often laid out square.

Ventilation ducts

The thickness of the walls of the channels in the external walls of buildings is taken taking into account the design temperature of the outside air. The height of the exhaust ventilation ducts located next to chimneys, should be taken equal to the height of these pipes.

Dimensions of indentations (cuts) for stoves and smoke ducts.

Recess (cut) is the air space between the outer surface of the furnace, chimney or smoke channel, on the one hand, and a combustible wall, partition or other building structure, on the other hand. Leave an air gap (recess) along the entire height of the stove or chimney.

When installing grooves in floors, independent settlement of furnaces and pipes should be ensured. Supporting the cuttings on structural elements overlaps are not allowed. The cutting height should be greater than the thickness of the ceiling by the amount of possible settlement of the building and 70 mm above the layer of combustible backfill.

Horizontal cuts in the plane of the ceiling should be carried out simultaneously with the main masonry.

The gaps between the ceiling and the groove must be filled with clay mortar mixed with asbestos.

For walls or partitions made of flammable and slow-burning materials, the deviation should be taken in accordance with Table 1 (see below), and for factory-made stoves it should be taken according to the manufacturer’s documentation.

The dimensions of the indentations (cuts) of furnaces and channels, taking into account the thickness of the furnace wall, should be taken equal to:

a) 500 mm - to building structures made of combustible materials;
b) 380 mm - to a wall or partition made of non-combustible materials, adjacent at an angle to the front of the stove and protected from fire from the floor to a level 250 mm above the top of the combustion door:

• plaster on metal mesh— thickness 25 mm
• or metal sheet By asbestos cardboard- 8 mm thick.

The dimensions of the cuts should be taken in accordance with mandatory requirements to the “derogations” given in Table 1:

Table 1. Dimensions of grooves according to SNiP 2.01.01-82

The cutting should be 70 mm greater than the thickness of the ceiling (ceiling). The furnace section should not be supported or rigidly connected to the building structure. In the walls covering the setback, openings should be provided above the floor and at the top with gratings with a clear cross-sectional area of ​​at least 150 cm2 each.

The floor in a closed setback should be made of non-combustible materials and located 70 mm above the floor of the room.

The distance between the top of the furnace floor, made of three rows of bricks, should be taken:

with a ceiling made of flammable or low-combustible materials, protected with plaster on a steel mesh or steel sheet on asbestos cardboard 10 mm thick:

• 250 mm - for ovens with intermittent firing
• 700 mm - for stoves long burning

and with an unprotected ceiling:

• 350 mm - for ovens with intermittent firing
• 1000 mm - for long-burning furnaces

For kilns with an overlap of two rows of bricks, the indicated distances should be increased by 1.5 times. Distance between top metal furnace and the overlap should be taken:

• with thermally insulated ceiling and protected ceiling - 800 mm
• with non-thermally insulated ceiling and unprotected ceiling - 1200 mm

Vertical cutting of furnaces and pipes installed in the openings of combustible partitions is carried out to the entire height of the furnace or pipe.

In the walls of the closed space above the stove, two openings with gratings should be provided at different levels, each having a clear cross-sectional area of ​​at least 150 cm2. The retreat is left open or sealed on both sides with bricks or other fireproof materials.

Side walls closed chamber It is not allowed to tie the offsets with the main masonry of the stove. The floor in the air gap is lined with bricks one row above the floor level of the room. The width of the setback and the method of insulating walls and partitions in the setbacks are taken in accordance with the data given in Table 3:

Table 3. Types and sizes of indentations

The distances from the upper planes of the stove floors to the combustible (or fire-protected) ceilings of the premises must be no less than those indicated in Table 4:

Table 4. Distances from the top of furnace floors to combustible ceilings, mm

The gap between the top of the thick-walled stove and the ceiling can be closed on all sides brick walls. In this case, the thickness of the upper ceiling of the furnace must be at least 4 rows brickwork, and the combustible ceiling must be protected from fire.

Chimneys and roof structures

Chimneys should be installed higher than the roof tall buildings, attached to a building with stove heating. The wall thickness of the chimney head above the roof must be at least the thickness of one brick.

The distance from the outer surfaces of chimneys to rafters, sheathing and other roofing parts made of flammable and slow-burning materials should be kept clear:

• from brick or concrete chimneys - at least 130 mm
• from ceramic pipes without insulation - 250 mm
• and for thermal insulation with heat transfer resistance - 0.3 m2 x t°C/W with non-flammable or low-combustible materials - 130 mm

The space between chimneys and roof structures made of non-combustible and low-combustible materials should be covered with non-combustible roofing materials. Gaps between ceilings, walls, partitions and divisions should be filled with non-combustible materials.

The space between the ceiling (in front of the roof) of a heat-intensive stove and the ceiling made of flammable and slow-burning materials may be covered on all sides with brick walls. In this case, the thickness of the furnace ceiling should be increased to four rows of brickwork.

Comments:

• Performance Standards and Channels natural ventilation
• Channel parameters and ventilation calculations
• Ventilation calculation example

is a system in which there is no forced driving force: a fan or other unit, and the flow of air occurs under the influence of pressure differences. The main components of the system are vertical channels starting in the ventilated room and ending at least 1 m above the roof level. The calculation of their number, as well as the determination of their location, is carried out at the design stage of the structure.

The temperature difference at the lower and upper points of the duct causes the air (it is warmer in the house than outside) to rise upward. The main indicators that affect the traction force are: the height and cross-section of the channel. In addition to them, the efficiency of the natural ventilation system is affected by the thermal insulation of the shaft, turns, obstacles, narrowing in the passages, as well as wind, and it can either contribute to the draft or reduce it.

Such a system has a fairly simple arrangement and does not require significant costs both during installation and during operation. It does not include mechanisms with electric drives, it operates silently. But natural ventilation also has disadvantages:

• operating efficiency directly depends on atmospheric conditions, so it is not used optimally most of the year;
• performance cannot be adjusted, the only thing that needs to be adjusted is air exchange, and then only downward;
• in the cold season it causes significant heat loss;
• does not work in hot weather (there is no temperature difference) and air exchange is possible only through open vents;
• If work is ineffective, dampness and drafts may occur in the room.

Performance standards and natural ventilation channels

The optimal location for the channels is a niche in the wall of the building. When laying, remember that the best traction will be with a flat and smooth surface of the air ducts. To service the system, that is, cleaning, you need to design a built-in hatch with a door. To prevent debris and various sediments from ending up inside the mines, a deflector is installed above them.

According to building regulations the minimum performance of the system should be based on the following calculation: in those rooms where people are constantly present, the air should be completely renewed every hour. As for other premises, the following should be removed:

• from the kitchen - at least 60 m³/hour when using an electric stove and at least 90 m³/hour when using a gas stove;
• baths, toilets - at least 25 m³/hour, if the bathroom is combined, then at least 50 m³/hour.

When designing a ventilation system for cottages, the most optimal model is one that involves laying a common exhaust pipe through all rooms. But if this is not possible, then the ventilation ducts are laid from:

Table 1. Ventilation air exchange rate.

• bathroom;
• kitchens;
• storage room - provided that its door opens in living room. If it leads to the hall or kitchen, then only a supply duct can be installed;
• boiler room;
• from rooms that are separated from rooms with ventilation by more than two doors;
• if the house has several floors, then starting from the second, if there is entrance doors From the stairs, channels are also laid from the corridor, and if there are none, from each room.

When calculating the number of channels, it is necessary to take into account how the floor on the first floor is equipped. If it is wooden and mounted on joists, then a separate passage is provided for air ventilation in the voids under such a floor.

In addition to determining the number of air ducts, the calculation of the ventilation system includes determining the optimal cross-section of the ducts.

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Channel parameters and ventilation calculations

When laying air ducts, both rectangular blocks and pipes can be used. In the first case, the minimum side size is 10 cm. In the second smallest area air duct cross-section is 0.016 m², which corresponds to a pipe diameter of 150 mm. A channel with such parameters can pass a volume of air equal to 30 m³/hour, provided that the pipe height is more than 3 m (with a lower value, natural ventilation is not provided).

Table 2. Ventilation channel performance.

If it is necessary to increase the performance of the air duct, then either the cross-sectional area of ​​the pipe expands or the length of the channel increases. The length, as a rule, is determined by local conditions - the number and height of floors, the presence of an attic. In order for the traction force in each of the air ducts to be equal, the length of the channels on the floor must be the same.

To determine what size ventilation ducts need to be laid, it is necessary to calculate the amount of air that needs to be removed. It is assumed that outside air enters the premises, then it is distributed into rooms with exhaust shafts and is exhausted through them.

The calculation is made floor by floor:

1. The smallest amount of air that should come from outside is determined - Q p, m³/hour, the value is found according to the table from SP 54.13330.2011 “Residential multi-apartment buildings” (Table 1);
2. According to the standards, the smallest amount of air that needs to be removed from the house is determined - Q in, m³/hour. The parameters are specified in the section “Performance standards and natural ventilation channels”;
3. The obtained indicators are compared. The minimum productivity - Q р, m³/hour - is taken to be the largest of them;
4. For each floor, the height of the channel is determined. This parameter is set based on the dimensions of the entire building;
5. According to the table (Table 2), the number of standard channels is found, and their total performance should not be less than the minimum calculated;
6. The resulting number of channels is distributed between rooms where air ducts must be present.

Ventilation is important for any home, which will prevent mustiness, unpleasant odors and dampness from entering it. One option to get rid of this is to provide ventilation ducts in the brick walls. With a hidden “hood” there will be a good microclimate in the house.

Indispensable rules of the device

Exhaust ventilation channels are installed when laying the walls of the house, inside them. If the wall is 38 cm thick - in 1 row, if 64 cm - in 2 rows. Traditional section - 140x140 mm. The same solution is used as for masonry at home. It is allowed to use a solution of clay and sand.

Before you do ventilation duct V brick wall, you need to have a full-bodied ceramic brick. You will need a template that you can make yourself. This is a board (length, width, thickness - 2.5 m x 140 mm x 25 mm), in which cutouts are made corresponding to the size of the ventilation ducts and their location on the wall. We need inventory buoys - hollow boxes made of boards. Their cross section is like that of a channel, the height should be 8-10 bricks. Cleaning of the masonry will be done by mopping, checking for “cleanliness” - with a test ball on a cord with a diameter of 100 mm.

The masonry is done vertically. It must be moved away from the door opening as well as from the wall joints by no less than 380 mm. The adjacent channel and chimney are insulated with each other using heat-resistant materials and the walls of the channel are enlarged.

Practical experience

The installation of a ventilation duct is made taking into account the following important points:

And if without masonry

A homemade ventilation duct in brick walls is made using pipes. But even in this case, it is necessary that each room has its own air duct. One of the exits should be located at a height of two meters above the foundation (higher is possible) inside the outer wall (it draws in air from the street). The second is on the roof (removes air from the house). All channels are connected to it. The pipe should rise one meter above the roof. The inlets for the grilles are located under the ceiling, no lower than 10 cm. They are closed with dampers that regulate the air flow.

You can combine hoods from the sauna-kitchen, bathroom-toilet. All four can be combined in the attic. It is important that there are reliable seals at the joints. Information “in a bouquet” can only be done if the services are located on one side of the house. IN one-story house they can be mounted in the ceiling (they go out to the roof through the attic). Pipes in the attic should be insulated.

For natural ventilation risers, the diameter of the pipes is 125 x 150 mm, for forced ventilation - 100 x 125 mm. The choice of materials depends on what the owner likes and the price. They can be made of polymers, galvanized, asbestos cement, concrete. When installing, pipes are lowered into the space between the walls and cemented. The tightness at the point where the ventilation pipe exits onto the roof is important. To do this, use a passage element made of rubber or silicone. The air duct and the exhaust outlet are connected by a corrugated pipe.

How to make pipes yourself

You can make a ventilation duct in a brick wall yourself, even if it is thin. With a partition half a brick thick, an asbestos-cement pipe with a diameter of 120 mm (internal - 100) will “fit in”. The opening in this case should be 130 mm wide. Having lowered the pipe into it, it is strengthened with cement mortar.

In the absence of a pipe, it is made like this: two large half-waves of slate the right size fastened with wire. It is attached to a brick cabinet, which is laid out flush with the partition. But there is another way: on the sides of the partition in its upper part, lay a couple of bricks on the edge and install the structure. Under ventilation grille a hole is cut out at the bottom where it is attached. At the end - plastering. The part that ends up in the attic should be insulated with asbestos (foil will also do). On the roof it should be no closer than a meter from its highest point.

There are even thinner openings - a quarter of a brick. In this case, the cabinet will be replaced with a structure that can be made from strips flat slate(width 20 cm). They are inserted into the canal, spread out and tied with wire, and plastered.

Hood connection

In the kitchen, only the ventilation installed in the wall may be “missing”, especially if you cook often and the kitchen is small. A hood helps out by removing unpleasant air from the kitchen. It is important to connect it correctly to the ventilation duct. It is desirable that the distance to the ventilation shaft be minimal. Otherwise, the effect of the hood will be reduced. And long air ducts look ugly.

For connection, special air ducts and adapters are required. The elements are connected hermetically. For safety and efficient work a number of rules are important. When connecting an exhaust pipe, it should not block the entire ventilation duct: when it is not working, the main ventilation operates from air draft. To do this, you need to remember to place a grill over the entrance of the exhaust pipe.

To ensure that the hood does not fail, the air must not be obstructed. This is why it is important to keep the duct length shorter. And it’s better to forget about turns altogether. The smoothness of the pipe will also contribute to high-quality traction. Therefore, corrugated pipelines, which are preferred due to their flexibility, still hinder the air flow. If you can't do it, you need to smooth out the turns. Danger: if a gas heater is used in the kitchen, the hood must not be vented into its smoke duct

The most common mistakes

1. The ventilation duct is not installed in the kitchen, bathroom, bathrooms, and closets without windows.
2. Instead of a channel, there is a hole in the wall, closed by a grille. This does not provide traction, and therefore is not effective.
3. The windows and doors are hermetically sealed and there are no ventilators. In such conditions, ventilation does not work, which will be reported unpleasant odors, condensation, mold.
4. “Overkill” with ventilation. Forced ventilation, if there is a special hood, for example, a fireplace, is not allowed.
5. There is no hood at all in the room with the fireplace. A properly functioning fireplace chimney is safe. But when the fireplace is lit, smoke can enter the room; it is better to have a separate ventilation duct in it.
6. There is no hood in the room, which is separated from the rest by two doors. “Overcoming” them with air flow is sometimes completely impossible, as is effective ventilation.
7. Uninsulated channel. If the channels are in external walls, they must be insulated, otherwise the traction force is lost.
8. Gas pipes must not be installed in the wall. Do this only in fines with screens that have holes for ventilation.
9. Deviation of the vertical channel may interfere with ventilation. Maximum 30°. If the job is done, there is only one way out - install an additional fan. Just not in a room where there is a fireplace!